JP2014022702A - Junction box for solar cell module and manufacturing method of solar cell module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a junction box for a solar cell module which prevents a contact defect that occurs between a terminal of the junction box and a module lead of the solar cell module.SOLUTION: A junction box 100 for a solar cell module comprises: a casing 101 including a module mounting surface 103 to be mounted to the solar cell module; and a terminal 102 protruding from the module mounting surface 103. The casing 101 is mounted to the solar cell module by matching and fixing the module mounting surface 103 to a box mounting surface of the solar cell module including an opening where a module lead is exposed. A bottom face of the terminal 102 is opposed to a top face of the module lead, an electrode for resistance welding is pressed against an electrode abutting surface on a top face of the terminal 102, and the bottom face of the terminal 102 and the top face of the module lead are resistance-welded by making current flow from the electrode.

Description

  The present invention relates to a junction box (terminal box) for a solar cell module.

  Conventionally, in a solar cell module, a ribbon-shaped electric wire (module lead) is used as a lead wire for converting light energy directly into electric power and taking out the electric power as an output. Further, in order to supply the extracted output to an external device or the like, a junction box is used for connection between a cable connected to the external device or the like and a solar cell module. The junction box is provided with a terminal (or a terminal plate) for connection with the module lead of the solar cell module. Conventionally, the module lead is connected to the terminal by soldering.

  However, in the connection by soldering, mechanical strength such as tensile strength may be insufficient. Further, in the soldering process, the manufacturing process of the solar cell may require a soldering process and increase the manufacturing cost. Therefore, in the prior art, a method of manufacturing a solar cell module by connecting a module lead and a terminal by using spot welding (resistance welding) (for example, JP 2010-263071 A (Patent Document 1)), a spring A method of manufacturing a solar module by bringing a terminal having elasticity such as that above into contact with a module lead and connecting it by a pressing force of a spring (for example, Japanese Patent Laid-Open No. 2005-340821 (Patent Document 2)) It is used.

  More specifically, in Japanese Patent Application Laid-Open No. 2010-263071 (Patent Document 1), when a terminal box having a terminal plate is bonded to a terminal box connection surface of a solar cell module, the terminal box comes out of the terminal box connection surface. The lead wire (ribbon-shaped electric wire, module lead) is placed on the terminal plate of the terminal box, and the lower surface of the lead wire is welded to the upper surface of the terminal plate by spot welding. On the other hand, in Japanese Patent Application Laid-Open No. 2005-340821 (Patent Document 2), when a housing provided with a spring contact is attached to a solar element provided with a contact surface for taking out a voltage generated by a solar cell, the spring contact is used as the contact. The connection is maintained by the pressing force of the spring in contact with the upper surface of the surface.

JP 2010-263071 A Japanese Patent Laying-Open No. 2005-340821

  When spot welding is used to connect a terminal plate of a terminal box and a lead wire coming out from a terminal box connection surface of a solar cell module as in JP 2010-263071 A (Patent Document 1), spot welding is used. A pair of electrodes are brought into contact with the upper surface of the lead wire, a current is passed while the lead wire and the terminal plate are crimped, and the respective metals of the lead wire and the terminal plate are melted and joined by the resistance heat. However, since the lead wire with which the pair of electrodes for spot welding are in contact is a ribbon-shaped electric wire that is thinner than the thickness of the terminal plate, before the metal on the surface of the terminal plate located under the lead wire melts In addition, the metal on the surface of the lead wire is melted first, which may cause a problem of poor contact in which the lead wire and the terminal plate cannot be joined well. Moreover, the problem that the lead wire melt | dissolved by spot welding will adhere to the electrode for spot welding, without joining with a terminal board may also arise. Furthermore, in the manufacturing method of the solar cell module as described above, a step for positioning the lead wires on the upper surface of the terminal plate is necessary for spot welding, and the manufacturing cost is high.

  Further, as in JP-A-2005-340821 (Patent Document 2), it is insufficient to maintain the connection between the contact surface of the solar element and the spring contact only by the pressing force of the spring. May cause poor contact, such as an increase in Furthermore, due to deterioration over time, the spring pressing force is weakened, causing contact failure, and it may not be possible to receive sufficient power from the solar cell.

  In order to solve such a problem, a solar cell junction box having a terminal whose lower surface is firmly joined by resistance welding on the upper surface of the module lead of the solar cell module, and manufacture of the solar cell module to which the junction box is attached Provide a method.

  In one embodiment of the present invention, a junction box for a solar cell module includes a housing having a module mounting surface for mounting on the solar cell module, and a terminal protruding from the module mounting surface. Is attached to the solar cell module by fixing the module mounting surface to the box mounting surface of the solar cell module having an opening in which the module lead is exposed, and the lower surface of the terminal is the upper surface of the module lead. The resistance welding electrode is pressed against the electrode contact surface on the upper surface of the terminal, and current is passed from the electrode, whereby the lower surface of the terminal and the upper surface of the module lead are resistance-welded. Configured as follows.

  As a preferred embodiment of the present invention, after the bottom surface of the terminal and the top surface of the module lead are resistance welded, when the electrode is separated from the terminal, the terminal returns to its original position by elastic force, and the terminal The welded module lead is in a state of floating away from the base of the solar cell module.

  As a preferred embodiment of the present invention, the terminal has a protruding portion formed by raising the surface of the portion on the lower surface portion of the upper surface of the terminal opposite to the electrode contact surface.

  As a preferred embodiment of the present invention, the electrode is composed of a plurality of electrodes, and the terminal is between a plurality of electrode contact surfaces against which each electrode is pressed, and has a slit at the center of the terminal. .

  As a preferred embodiment of the present invention, the electrode is composed of a plurality of electrodes, and the terminal is between a plurality of electrode contact surfaces against which each electrode is pressed, and a pair of slits at both ends of the terminal Have

  Moreover, in one embodiment of the present invention for a method for manufacturing a solar cell module, a junction box including a housing having a module mounting surface for mounting on the solar cell module and a terminal protruding from the module mounting surface is provided. The method for manufacturing a solar cell module includes a box mounting surface of the solar cell module having an opening in which the module lead is exposed so that an upper surface of the module lead of the solar cell module and a lower surface of the terminal face each other. And attaching the housing to the solar cell module by aligning and fixing the module mounting surface, and pressing an electrode for resistance welding against the electrode contact surface on the upper surface of the terminal. A step of resistance welding the lower surface of the terminal and the upper surface of the module lead by flowing. .

  The junction box for the solar cell module according to the present invention is not the module lead of the solar cell module, but the electrode for resistance welding is generally pressed against the terminal of the junction box thicker than the thickness of the module lead. Compared with the prior art, conditions (for example, energization time, energization current) at the time of resistance welding can be easily adjusted, the terminals and the module leads can be sufficiently welded, and poor contact can be prevented.

  The junction box for a solar cell module according to the present invention does not require a step of arranging the module lead of the solar cell module on the upper surface of the terminal of the junction box, and can reduce the manufacturing cost.

  Furthermore, it is possible to prevent the welding object (terminal, module lead, etc.) from sticking to the electrode for resistance welding.

FIG. 1 is a diagram showing a junction box for a solar cell module. FIG. 2 is a diagram showing the solar cell module before the junction box is attached. FIG. 3 is a cross-sectional view showing a state before the junction box is attached to the solar cell module and the terminal of the junction box and the module lead of the solar cell module are welded. FIG. 4 is an enlarged cross-sectional view of opposing terminals and module leads in the state of FIG. FIG. 5 is a cross-sectional view showing a state during welding of the terminal of the junction box and the module lead of the solar cell module. FIG. 6 is an enlarged cross-sectional view of a portion during welding in the state of FIG. FIG. 7 is an enlarged cross-sectional view of a portion where the electrode and the module lead are welded away from the terminal in the state of FIG. FIG. 8 is a view showing an embodiment in which a protruding portion and a slit are provided on the terminal of the junction box.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiment, and the repetitive description thereof will be omitted.

  (A) and (b) of Drawing 1 is a figure showing junction box 100 for solar cell modules concerning one embodiment of the present invention. A junction box 100 for a solar cell module according to this embodiment includes a housing 101, terminals 102, a module mounting surface 103, and a lid body 104. The housing 101 accommodates the terminal 102 inside, and the tip of the terminal 102 projects outward from the housing 101. More specifically, the lower surface at the tip of the terminal 102 (that is, the welding surface with the module lead 202 of the solar cell module) protrudes from the housing 101 to the outside of the module mounting surface 103.

  The terminal 102 is a metal having an elastic force. For example, nickel plating is applied to the surface of a terminal base material (copper alloy) having a thickness of about 0.3 mm with a thickness of about 1 μm, and tin plating is further applied thereon with a thickness of about 1 to 2 μm. It is a thing. The junction box according to this embodiment includes two terminals 102a and 102b. However, the number of terminals 102 is not limited to this embodiment, and the junction box has a number of terminals other than two. It can also be provided.

  The module attachment surface 103 is attached to the box attachment surface 206 of the solar cell module by bonding with an adhesive or the like. The lid body 104 is detachable, for example, removed when maintaining the junction box 100 attached to the solar cell module 200. In addition, when the terminal 102 of the junction box 100 is resistance-welded to the module lead 202 of the solar cell module 200, the terminal 102 is removed in order to put an electrode for resistance welding in the junction box 100.

  FIG. 2 is a diagram showing the solar cell module 200 before the junction box 100 is attached according to an embodiment of the present invention. The solar cell module 200 according to the present embodiment basically includes a panel 201, module leads 202, an opening 205, and a base 207 (not shown in FIG. 2). The panel 201 is a glass substrate such as tempered glass. The module lead 202 is exposed from the opening 205 on the surface of the panel 201. Although the solar cell module 200 according to the present embodiment includes two module leads 202a and 202b, the number of the module leads 202 is not limited to the present embodiment, and the solar cell module 200 includes two module leads 202. Other number of module leads may be provided.

  As shown in the cross-sectional view of FIG. 3, the module lead 202 is an electric wire that is located between the panel 201 and the base body 207 and flows current generated by the solar cell. That is, the module lead 202 is positioned below the box mounting surface 206 by the thickness of the panel 201. Further, the module lead 202 includes a lead electrode 203 as a conductor and a film 204 as an insulator. For example, the lead electrode 203 is coated with solder plating (tin silver copper) with a thickness of about 20 μm on both sides of a core material (pure copper) having a thickness of about 50 μm, and is further applied to the adhesive surface with the film 204. A 10 μm adhesive paste is applied to adhere to the film 204. The film 204 is a PET film having a thickness of about 50 μm, for example.

  The opening 205 can receive the terminal 102 such that the lower surface of the terminal 102 overlaps the upper surface of the module lead 202 in order to weld the terminal 102 to the module lead 202 exposed therefrom. The surface around the opening 205 is a box mounting surface 206 for fixing the module mounting surface 103 of the junction box 100 with an adhesive or the like.

  FIG. 3 is a cross-sectional view showing a state before the junction box 100 according to the embodiment of the present invention is attached to the solar cell module 200 and the terminals 102 and the module leads 202 are welded. The module attachment surface 103 of the junction box 100 and the box attachment surface 206 of the solar cell module 200 are fixed with an adhesive or the like, and the junction box 100 is attached to the solar cell module 200. At the time of attachment, the terminals 102a and 102b protruding from the inside of the housing 101 to the outside of the module attachment surface 103 are inserted into the opening 205, and are arranged directly above the module leads 202a and 202b, respectively. The position of the housing 101 is adjusted.

  FIG. 4 shows an enlarged cross-sectional view (IV portion in FIG. 3) of the opposing terminal 102a and module lead 202a. As can be seen from the cross-sectional view, in one embodiment according to the present invention, when the junction box 100 is attached to the solar cell module 200, a gap (between the terminals 102a and 102b and the module leads 202a and 202b, respectively) Space). That is, although the terminal 102 protrudes outside the module mounting surface 103, the protruding amount is configured to be within the thickness range of the panel 201. In another embodiment according to the present invention, the terminal 102 and the module 202 may slightly contact each other with the junction box 100 attached to the solar cell module 200.

  Further, referring to FIG. 4, the terminal 102a is arranged so as to face the module lead 202a, but more precisely, the lower surface of the terminal 102a, that is, the welding surface with the module lead 202a is the module lead 202a. Is arranged so as to be directly above the upper surface of the lead electrode 203a. The same applies to the other terminals 102b and module leads 202b.

  The cross-sectional view of FIG. 5 shows a state in which the terminal 102 of the junction box 100 and the module lead 202 of the solar cell module 200 are being welded. The lid 104 at the top of the casing 101 of the junction box 100 is removed, and the resistance welding electrode 300 is inserted from the top of the casing 101. In one embodiment of the present invention, the electrode 300 is composed of two electrodes 300a and 300b, but may be a number of electrodes other than two. In FIG. 5, the electrodes 300a and 300b are pressed against the electrode contact surface 105 on the upper surface of the terminal 102a, respectively, so that the terminal 102a having elastic properties is connected to the upper surface of the module lead 202a (more precisely, the lead electrode). Crimped to the upper surface of 203a. Then, by passing a current through the electrode 300a and the electrode 300b, the terminal 102a and the module lead 202a are welded by resistance heat. The same applies to the resistance welding between the other terminals 102b and the module lead 202b.

  FIG. 6 is an enlarged cross-sectional view (VI portion in FIG. 5) of the terminal 102a and the module lead 202a during resistance welding shown in FIG. The terminal 102a is pressed against the upper surface of the lead electrode 203a of the module lead 202a by pressing the electrode contact surface 105 on the upper surface of the terminal 102a with the electrodes 300a and 300b. For example, if the electrode 300a is an anode and the electrode 300b is a cathode, the current from the electrode 300a flows through the lead electrode 203a through the terminal 102a and then flows again through the terminal 102a into the electrode 300b. At that time, due to resistance heat between the terminal 102a and the lead electrode 203a, a metal on the surface of the terminal 102a (for example, tin plating) and a metal on the surface of the lead electrode 203 (for example, solder plating (tin silver copper)). Melt and join.

  Resistance welding by the electrode 300 according to an embodiment of the present invention is adjusted based on various conditions in order to pass current as described above. For example, for the electrode 300 through which current flows, the shape, the applied pressure, the type of welding power source, the energizing time, the energizing current, the time for increasing the current from zero to a constant value (up slope), and the constant value falling to zero The time (down slope) to be taken into consideration is considered as a condition. Further, regarding the terminal 102, the position (that is, the height of the module lead 202 from the lead electrode 203), the shape, and the like are considered as conditions, and the material, the plate thickness, and the type of plating are common to the terminal 102 and the module lead 202. In addition, the plating thickness and the like are considered as conditions.

  If resistance welding is not performed under appropriate conditions, for example, in the previous example of FIG. 6, the current from the electrode 300a that is the anode does not flow through the lead electrode 203a through the terminal 102a, but mainly the terminal 102a. , It flows into the electrode 300b, which is a cathode, and sufficient resistance heat cannot be obtained and welding may not be performed.

  Therefore, in resistance welding in an embodiment according to the present invention, for example, the energizing current and energizing time in the electrode 300 are set as variable conditions, and the other conditions as described above are fixed and the conditions are adjusted. By adjusting the energization current and the energization time, appropriate conditions are found for sufficient resistance welding between the terminal 102 and the module lead 202. If it is difficult to find appropriate conditions for the energization current and energization time, conditions to adjust as variable conditions from other fixed conditions (for example, electrode shape, electrode pressure, etc.) Can be selected. Then, the adjustment is performed again using a new variable condition.

  In addition, if the thickness of the object that contacts the electrode 300 (in the embodiment of the present invention, the terminal 102) is thin, it is difficult to adjust the various conditions of resistance welding as described above. If the object to contact 300 is thick, a relatively large current can be passed for a long time, so that it is easy to adjust the resistance welding conditions.

  7 shows a state in which the terminal 102a and the module lead 202a after the resistance welding is completed and the electrode 300 is removed from the state where the terminal 102a and the module lead 202a are crimped by the electrode 300 for resistance welding shown in FIG. It is an enlarged view which shows the state of. The terminal 102a and the lead electrode 203a are joined by resistance welding, the terminal 102a returns to its original position by elastic force, and the module lead 202a welded to the terminal 102a is in a state of floating away from the base 207. As described above, the module lead 202a floats away from the base body 207, so that the solar cell module 200 after the junction box 100 is attached is subjected to impacts during transportation and transportation, vibration due to rain and wind, and the like. Even so, the impact and vibration can be absorbed, and the occurrence of problems such as peeling of the welded portion can be avoided.

  As described above, according to the present invention, by arranging the terminal 102 on the module lead 202 and bringing the electrode 300 into contact with the terminal 102 thicker than the module lead 202, a relatively large current can flow for a long time. Therefore, it becomes easier to adjust various conditions when performing resistance welding compared to the prior art, and contact failure between the terminal 102 and the module lead 202 can be reduced by sufficient resistance welding.

  In general, depending on the resistance welding conditions, the contact resistance of the electrode contact surface 105 between the terminal 102 and the electrode 300 is lower than the contact surface between the module lead 202 and the terminal 102, and is lower than between the module lead 202 and the terminal 102. When current flows between the electrode 300 and the terminal 102, the electrode 300 and the terminal 102 are in a welded state, and the terminal 202 may stick to the electrode 300 in some cases. In the present invention, since the resistance welding conditions can be easily adjusted as described above, occurrence of such sticking can be reduced.

  FIG. 8 shows another embodiment of the present invention. 8 (a1) and 8 (a2), a concave electrode contact surface 106 is provided on the upper surface of the terminal 102 against which the electrode 300 for resistance welding is pressed, and a convex protrusion 107 is provided on the lower surface of the terminal 102. Terminal 102 is shown. The electrode contact surface 106 and the protruding portion 107 of the terminal 102 are formed by processing such as embossing. Further, only one of the electrode contact surface 106 and the protruding portion 107 may be formed on the terminal 102. In the embodiment shown in FIG. 8, the number of the electrode contact surfaces 106 and the protrusions 107 is two, but the electrode contact surfaces 106 and the protrusions 107 can be formed by a number other than two. is there.

  The shape of the electrode contact surface 106 may be, for example, a circular shape with a recessed (concave) center, but may be changed based on the shape of the electrode 300 and various conditions set when resistance welding is performed. Is also possible. Further, the shape of the protruding portion 107 can be, for example, a circular shape with a raised center (convex shape), but is changed based on the shape of the electrode 300 and various conditions set when resistance welding is performed. It is also possible.

  In another embodiment of the present invention shown in FIGS. 8A1 and 8A2, the electrode 300 is pressed against the electrode contact surface 106 of the terminal 102, and the protruding portion 107 is formed by the elastic property of the terminal 102. The lead 202 contacts the upper surface of the lead electrode 203. When performing resistance welding, the current from one electrode 300 flows through the lead electrode 203 through the protruding portion 107 in contact with the lead electrode 203 from the electrode contact surface 106 of the terminal 102. The current flowing through the lead electrode 203 then flows to the other electrode 300 through another protruding portion 107 that is in contact with the lead electrode 203.

  Since the protruding portion 107 is provided on the terminal 102, the protruding portion 107 and the lead electrode 203 can be sufficiently crimped. Therefore, the contact resistance between the lead electrode 203 and the protruding portion 107 (that is, between the module lead 202 and the terminal 102). The contact resistance of the contact surface can be kept low. Thereby, the contact resistance of the electrode contact surface 106 between the terminal 102 and the electrode 300 becomes larger than the contact resistance of the contact surface between the module lead 202 and the terminal 102 without adjusting other conditions of resistance welding. , Sticking of the terminal 202 to the electrode 300 can be prevented.

  Further, in one embodiment of the present invention, the resistance welding between the terminal 102 and the module lead 202 melts the solder plating on the surface of the lead electrode 203 by the resistance heat generated by the current while applying a weight to crimp them. ing. Therefore, when the energization time is long, solder plating may be scattered and dust may be generated. However, as shown in FIG. 8, by providing the protruding portion 107 on the terminal 102, more current can flow to the module lead 202 through the protruding portion 107 in a short time. Resistance welding can be completed before dusting due to scattering occurs.

  FIGS. 8B1 and 8B2 show still another embodiment in which a rectangular slit 108 is provided at the center between two electrode contact surfaces 106 on the upper surface of the terminal 102. FIG. The number of slits 108 is not limited to one, and a plurality of slits can be provided as necessary. The slit 108 between the electrode contact surfaces 106 bypasses an energization path through which current flows from one electrode 300 through the terminal 102 to the other electrode 300 during resistance welding, and energizes the module lead 202 side. It has the effect of facilitating.

  Further, FIG. 8C shows a modification of the slit in which a pair of rectangular slits 109 are provided at both ends between the two electrode contact surfaces 106 on the upper surface of the terminal 102. The number of the slits 109 is not limited to a pair, and a plurality of pairs of slits can be provided as necessary. Similar to the slit 108, the slit 109 has an effect of facilitating the current flow during resistance welding to the module lead 202 side.

  The junction box according to the present invention is attached to a solar cell module and can be used to obtain electricity generated by the solar cell.

DESCRIPTION OF SYMBOLS 100 Junction box 101 Housing | casing 102,102a, 102b Terminal 103 Module attachment surface 104 Cover body 105 Electrode contact surface 106 Electrode contact surface 107 Protruding part 108,109 Slit 200 Solar cell module 201 Panel 202, 202a, 202b Module lead 203 , 203a, 203b Lead electrode 204, 204a, 204b Film 205 Opening 206 Box mounting surface 207 Base 300, 300a, 300b Electrode

Claims (7)

A housing having a module mounting surface for mounting on a solar cell module;
And a terminal protruding from the module mounting surface,
The housing is attached to the solar cell module by fixing the module mounting surface to the box mounting surface of the solar cell module having an opening in which the module lead is exposed,
The lower surface of the terminal is opposed to the upper surface of the module lead, the electrode for resistance welding is pressed against the electrode contact surface of the upper surface of the terminal, and a current flows from the electrode,
A junction box for a solar cell module, wherein the lower surface of the terminal and the upper surface of the module lead are resistance-welded. After the bottom surface of the terminal and the top surface of the module lead are resistance-welded, when the electrode is separated from the terminal, the terminal returns to its original position due to elastic force,
The solar cell module junction box according to claim 1, wherein the terminal-welded module lead floats away from the solar cell module substrate. 3. The solar cell according to claim 1, wherein the terminal has a protruding portion formed by raising a surface of the portion on a lower surface portion of the upper surface of the terminal opposite to the electrode contact surface. Junction box for modules. The electrode is composed of a plurality of electrodes,
4. The solar cell according to claim 1, wherein the terminal is between a plurality of electrode contact surfaces against which the respective electrodes are pressed, and has a slit at the center of the terminal. 5. Junction box for modules. The electrode is composed of a plurality of electrodes,
4. The terminal according to claim 1, wherein the terminal has a pair of slits at both ends of the terminal between a plurality of electrode contact surfaces against which the respective electrodes are pressed. 5. Junction box for solar cell module. The solar cell module according to any one of claims 1 to 5, wherein the housing of the junction box for a solar cell module is attached to the box attachment surface, and the terminal is resistance-welded to the module lead. module. In a method for manufacturing a solar cell module comprising a casing having a module mounting surface for mounting on a solar cell module and a junction box including a terminal protruding from the module mounting surface,
The module mounting surface is fixed to the box mounting surface of the solar cell module having an opening in which the module lead is exposed so that the upper surface of the module lead of the solar cell module faces the lower surface of the terminal. By attaching the housing to the solar cell module,
Pressing a resistance welding electrode against an electrode contact surface on the upper surface of the terminal and causing a current to flow from the electrode, thereby resistance welding the lower surface of the terminal and the upper surface of the module lead. A method for manufacturing a solar cell module.

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