JP4889377B2 - Terminal box for solar cell module using a plurality of semi-coated diodes connected in parallel and solar cell system using the same - Google Patents

Description

  The present invention relates to a terminal box and a solar cell system used for connecting solar cell modules constituting a solar power generation system to each other.

  A terminal box for a solar cell module usually includes a bypass diode for protecting the solar cell module from a reverse bias load.

  A conventional solar cell module terminal box includes a plurality of terminal plates connected to a plurality of output electrodes of a solar cell module, and a single resin-coated bypass diode disposed and connected between the plurality of terminal plates. have. (For example, refer to Patent Document 1).

  In addition, the inventors have conventionally arranged a terminal box for a solar cell module in which a diode with a lead terminal in which a plurality of diode chips are connected in parallel between a pair of lead terminals is arranged and connected between a pair of terminal plates as a bypass diode. Has proposed. (For example, refer to Patent Document 2).

Japanese Patent Laid-Open No. 11-26035 WO 2005/112133 (FIG. 8)

  The technology of solar cells is advancing day by day, and at present, a single solar cell module having a maximum output of 190 W and a nominal short-circuit current value of about 8 A is mainly used. The bypass diode for bypassing such a reverse bias load to the solar cell module is required to have a large electric capacity. When a current flows through the bypass diode, the heat generated by the bypass diode also becomes large.

  In order to use a conventional terminal box for a solar cell module including a single bypass diode for a solar cell module with a high output at present, it is necessary to newly increase the capacity of the diode and promote its heat dissipation.

  Moreover, the parallel connection diode with a lead terminal used for the conventional terminal box for solar cell modules was developed mainly for the purpose of being sandwiched in the solar cell module itself. For this reason, when the parallel connection diode with lead terminals is arranged in the terminal box, (1) heat dissipation is hindered at the joining portion of the lead terminals, and (2) a terminal plate having a large heat capacity in the same manner as the lead terminals of the parallel connection diode having a large heat capacity. As a result, the assembly process becomes difficult, for example, it is necessary to take care of the damage of the parallel-connected diode with lead terminals that does not have protective means such as resin coating, and (3) the plane size of the terminal box As a result, the internal volume of the terminal box increases, which leads to an increase in costs such as waterproofing measures. (4) Various problems arise, such as the need to specially manufacture parallel-connected diodes.

  Moreover, if the heat dissipation of the solar cell module terminal box is insufficient, the reliability of the solar cell system incorporating the same is lowered, and the lifetime of the entire solar cell system is shortened.

  Then, this invention makes it a subject to obtain the terminal box for solar cell modules which suppressed the heat_generation | fever of a bypass diode. Moreover, this invention makes it a subject to obtain the terminal box for solar cell modules which accelerates | stimulates heat dissipation of a bypass diode. Furthermore, this invention makes it a subject to obtain the terminal box for solar cells in which the internal volume of a terminal box does not increase unnecessarily. Moreover, this invention makes it a subject to obtain the terminal box for solar cell modules which an assembly process is easy. Another object of the present invention is to obtain a highly reliable terminal box for a solar cell module.

  Furthermore, an object of the present invention is to obtain a solar cell system with improved reliability and extended lifetime.

  Other problems of the present invention will become apparent from the description of the present invention.

A terminal box for a solar cell module according to an aspect of the present invention includes a plurality of terminal plates connected in a one-to-one correspondence to a plurality of output electrodes of the solar cell module, and at least a pair of the plurality of terminal plates. In the solar cell module terminal box that relays the solar cell module and the external connection cable, the rectifying device includes a lead frame and a diode chip. The diode chip is a flat plate formed by bonding a flat N-type semiconductor to a flat P-type semiconductor, the lead frame is a flat plate having conductivity, and the upper surface of the lead frame and the N of the diode chip. Type semi-coated die in which the electrodes of the type semiconductor are arranged in contact with each other, and the upper surface and the side surface of the diode chip are coated with resin Over de is disposed a plurality spaced apart from one another to, are those in which a plurality of the half-covering diodes electrically connected in parallel, wherein the lead frame the entire lower surface of the half-covering diodes, said terminal plate In contact.
Further, in the terminal box for the solar cell module, the pair of terminal plates are provided with a protruding portion and a cut portion at a position where the rectifying element is provided, and the protruding portion and the cut portion are arranged in mesh with each other. The half-covered diode has a P-side lead terminal extending from the P-type semiconductor electrode and an N-side lead terminal extending from the N-type semiconductor electrode through the lead frame. The P-side lead terminal and the N-side lead terminal protrude from the same side surface of the coating resin, and the P-side lead terminal and the N-side lead terminal are close to each other of the pair of terminal plates. The one terminal plate is connected to the protruding portion and the other terminal plate is connected to the protruding portion.

A terminal box for a solar cell module according to a preferred embodiment of the present invention has n (n is a positive integer of 3 or more) of the plurality of terminal plates, and an external connection cable is connected to the n terminal plates. Two external connection terminal plates and (n-2) intermediate terminal plates. The (n-2) intermediate terminal plates are provided with and connected to the plurality of half-covered diodes. The plurality of half-coated diodes are each composed of a single diode chip, and the plane area of the intermediate terminal plate is Qmm ² , and the plane area Rmm ² of the single diode chip constituting the half-coated diode is The relationship of Formula (1) may be satisfied.
Q ≧ 50R Formula (1)

In this preferred embodiment, the plane area of the intermediate terminal plate is set to a certain value or more. Unlike an external connection terminal plate that transmits heat through an external connection cable, the intermediate terminal plate needs to further promote heat dissipation to the environment. In this preferred embodiment, by setting the plane area to a certain value or more, the solar cell module terminal box is further promoted to dissipate heat from the intermediate terminal plate.
In the terminal box for a solar cell module according to a preferred embodiment of the present invention, the number of the plurality of half-coated diodes is two, and the two half-coated diodes have the same electrical design and shape design, and the half-coated diodes. The diodes may be arranged with an interval of 1 mm or more and 6 mm or less.
In this preferred embodiment, two similarly fabricated half-covered diodes are placed in close proximity. The value of the current flowing through the plurality of half-covered diodes connected in parallel varies depending on the environment where the individual half-covered diodes are placed, particularly the temperature environment. Since two similarly manufactured half-covered diodes are arranged close to each other, the temperature environment and the like are substantially equal. As a result, the current values flowing through the two half-covered diodes connected in parallel are substantially equal. A terminal box for a solar cell module in which heat generation of the diode is further suppressed.

  A solar cell system according to another aspect of the present invention includes a solar cell module and a terminal box for a solar cell module according to the present invention.

  The present invention described above, preferred embodiments of the present invention, and components included in these can be implemented in combination as much as possible.

The terminal box for the solar cell module according to the present invention has a pair of terminal plates arranged together with other components, so that the lead terminals of the half-covered diode can be shortened, and at the same time, the terminal box It becomes a solar cell module terminal box which can make a plane area small and can make the internal volume of a terminal box still smaller. At the same time, for example, a terminal box for a solar cell module that can further reduce the cost required for waterproofing the terminal box, such as filling with a silicone resin, is obtained. In addition, since the half-coated diode has a P-side lead terminal and an N-side lead terminal, and the two lead terminals are connected to the terminal plate, the mounting operation of the half-coated diode is facilitated.
In addition, since the terminal box for a solar cell module according to the present invention has a plurality of half-covered diodes arranged and connected to a single rectifying element placement position, the current flowing through each half-coated diode is reduced, This is a terminal box for a solar cell module in which heat generation of the diode is suppressed. In addition, since the present invention uses a semi-covered diode having a lead frame, heat dissipation is promoted by the lead frame, and at the same time, a terminal box for a solar cell module that does not unnecessarily increase the internal volume of the terminal box is obtained. . Furthermore, since the present invention uses a semi-coated diode, the connection structure in the diode is protected from mechanical deformation and impact by the coating, and the assembly process is easy and the reliability is improved for the solar cell module. It becomes a terminal box. At the same time, since the lead frame of the half-covered diode is in thermal contact with the terminal plate, the heat generated by the diode is conducted to the terminal plate through the lead frame and radiated.

  The solar cell system according to the present invention is a solar cell system in which the heat generation of the terminal box for the solar cell module is suppressed and the heat dissipation is promoted, so that the reliability is improved and the service life is extended.

  Hereinafter, a terminal box for a solar cell module and a solar cell system according to an embodiment of the present invention will be further described with reference to the drawings. The dimensions, materials, shapes, relative positions, etc. of the members and parts described in the embodiments of the present invention are not intended to limit the scope of the present invention only to those unless otherwise specified. It is just an illustrative example.

  FIG. 1 is an explanatory diagram of a solar cell system according to the present invention. The solar cell system 1 includes a solar cell module 6 and a terminal box 2, and includes an inverter (not shown), a distribution board (not shown), and the like as necessary.

  The solar cell module 6 normally includes a plurality of solar cells, and a certain number of these solar cells are connected in series to form a cell string, and power is taken out from output electrodes connected to both ends of the cell string. The terminal box 2 has an external connection cable 41 and an external connection cable 43, and connectors 42, 44 are provided at the tips of the external connection cables 41, 43, and are connected to the adjacent terminal boxes 2.

  In the illustrated solar cell module 6, the output electrode is taken out from the center of the back surface of the solar cell module 6, and the terminal box 2 is attached to the center of the back surface of the solar cell module 6 so as to cover the output electrode. . There is no restriction | limiting in the taking-out position of an output electrode, For example, you may take out an output electrode from the end surface of the solar cell module 6. FIG. Moreover, there is no restriction | limiting in arrangement | positioning of the terminal box 2, For example, the terminal box 2 may be arrange | positioned in the peripheral part of the solar cell module 6 back surface, and even if the terminal box 2 is arrange | positioned at the end surface of the solar cell module 6. Good.

  Next, the terminal box 2 will be described. 2 is a plan view of the terminal box 2, FIG. 3 is a plan view of the half-covered diode 11, FIG. 4 is a cross-sectional view of the half-covered diode 11 along the line AA 'in FIG. 3, and FIG. 3 is a cross-sectional explanatory view of the half-coated diode 11 taken along line BB ′ in FIG. In FIG. 5, for ease of explanation and understanding, the vertical and horizontal scales of the drawing are different, and the interval between components does not indicate the actual interval. FIG. 6 is an explanatory diagram of the shape and the like of the intermediate terminal plates 33a and 33b.

  In the terminal box 2, an N-side external connection terminal plate 32a, an intermediate terminal plate 33a, an intermediate terminal plate 33b, and a P-side external connection terminal plate 32b are arranged in the housing 10. Hereinafter, the N-side external connection terminal plate 32a, the intermediate terminal plate 33a, the intermediate terminal plate 33b, and the P-side external connection terminal plate 32b may be collectively referred to as a terminal plate. The output electrode 7 of the solar cell module is connected to the external connection terminal plates 32a and 32b and the intermediate terminal plates 33a and 33b. The output electrode 7 is usually a ribbon-shaped electric wire. The connecting process between the output electrode 7 and these terminal plates is performed by a known process such as soldering, spot welding, or pressure welding. The illustrated terminal box 2 is a terminal box that receives four output electrodes, and includes two external connection terminal plates and 2 (4 minus 2) intermediate terminal plates.

  An external connection cable 41 is connected to the other end of the external connection terminal plate 32a, and an external connection cable 43 is connected to the other end of the external connection terminal plate 32b. A through portion 36 is provided at a part of the bottom surface of the housing 10, and the output electrode 7 is guided to the inside of the housing 10 through the through portion 36.

  Two half-covered diodes 11a and 11b are connected in parallel to the external connection terminal plate 32a and the intermediate terminal plate 33a so as to be separated from each other. Two half-covered diodes 11c and 11d are connected to the intermediate terminal plate 33a and the intermediate terminal plate 33b in parallel, spaced apart from each other. Two half-covered diodes 11e and 11f are connected to the intermediate terminal plate 33b and the external connection terminal plate 32b in parallel, spaced apart from each other.

  The two half-covered diodes (a pair of 11a and 11b, a pair of 11c and 11d and a pair of 11e and 11f) have the same electrical design and the same shape design. That is, a plurality of products are produced so that each half-coated diode has the same performance and the same size. From the viewpoint of suppressing the overheating of a single diode by equalizing the currents flowing through the plurality of half-covered diodes, it is preferable to use a plurality of half-covered diodes similarly manufactured. However, in the present invention, there may be three or more half-covered diodes arranged and connected at a single rectifying element connection location. The plurality of half-coated diodes do not necessarily have the same electrical design and the same shape design. In the present embodiment, the three sets of six half-covered diodes are all half-covered diodes having the same electrical design and the same shape design.

  Next, the connection structure and the like of the half-covered diode will be described with reference to FIGS. 3, 4, and 5. The half-covered diode is denoted by reference numeral 11.

  The half-covered diode 11 has a diode chip 12 disposed on the upper surface of a lead frame 21. The lead frame 21 is a conductive flat plate, for example, a copper plate plated with tin and bismuth (Sn-Bi). The diode chip 12 has a flat plate shape, and is obtained by bonding a flat N-type semiconductor 17 to a flat P-type semiconductor 13. The P-type semiconductor 13 and the N-type semiconductor 17 are known semiconductors, and are made by mixing impurities such as boron, aluminum, phosphorus, and arsenic with silicon or germanium, for example.

There are no particular restrictions on the electrical standard value (and size) of the diode chip. However, from the viewpoint of making a terminal box for a high-output solar cell module, and further increasing the maximum usable electrical standard value, it is possible to suppress the heat generation of the diode chip in the case of a small energization amount. As for the standard value, the lower limit value of I ₀ is usually 5 A (ampere) or more, preferably 8 A or more, more preferably 10 A or more. The upper limit of I ₀ is not particularly limited, but is usually 50 A or less from the viewpoint of economy.

Since generally the generated voltage of the solar cell is low, as long as the diode chips satisfying I ₀ described above, satisfies the value of V _RM. If the value of _VRM of such a diode chip is illustrated, a lower limit will be 600V (volt) or more, and an upper limit will be 2000V or less.

  When the flat diode chip is formed with a thickness of about 0.10 mm to 0.40 mm, the diode chip (single) satisfying the above electric standard value is 2.5 mm or more on one side, preferably 2.7 mm or more on one side. 0.0 mm or less, more preferably 3.5 mm or more and 8.0 mm or less on a side, more preferably 3.5 mm or more and 6.0 mm or less on a side, and particularly preferably 4.0 mm or more and 6.0 mm or less on a side, Other planar shapes that are equal.

  The lower surface of the diode chip 12 is an N-type semiconductor electrode surface 18, and the upper surface of the diode chip 12 is a P-type semiconductor electrode surface 14. The upper surface of the lead frame is connected to the electrode surface 18 of the N-type semiconductor of the diode chip.

  The electrode surface 14 of the P-type semiconductor is connected to the P-side lead terminal 15 through a connector 16. A connector 20 is connected to the upper surface of the lead frame, and the other end of the connector 20 is connected to the N-side lead terminal 19. That is, the electrode surface 18 of the N-type semiconductor is connected to the N-side lead terminal via the lead frame 21 and the connector 20.

  Structures located on the side end surface of the lead frame and the top surface of the lead frame (diode chip 12, connectors 16, 20, part of the P-side lead terminal 15, part of the N-side lead terminal 19 and top surface of the lead frame) Covered with a covering 26. 3, 4, and 5, the covering 26 is indicated by a one-dot chain line. That is, the upper surface and side surfaces of the diode chip 12 are covered with resin. For example, an epoxy resin can be used as the coating resin. The lower surface 22 of the lead frame is not covered with the coating resin and is exposed. Therefore, the heat generated by the diode chip is mainly radiated to the outside from the lower surface of the lead frame. In addition, when a part of the lower surface of the lead frame, preferably the entire lower surface of the lead frame, is arranged so as to contact the terminal plate, heat is conducted from the lead frame to the terminal plate, which further promotes heat dissipation of the diode chip. The

  In the present invention, the semi-coated diode means a diode in which the upper surface and side surfaces of the diode chip 12 are coated with a resin. For example, the upper surface of the lead frame and the region where the diode chip is not mounted There may be no resin coating. Further, the extended surface of the lower surface of the lead frame and the end surface of the covering may be on the same surface.

  In the present invention, the lead frame is conductive, and the N-side lead terminal may be omitted and the lead frame may be directly connected to the terminal plate. However, from the viewpoint of heat dissipation of the diode chip, it is preferable to enlarge the lead frame and the terminal plate. In this way, the heat capacity of the lead frame and the terminal plate is increased, and the connection processing between the lead frame and the terminal plate (for example, soldering) Therefore, it is preferable to provide an N-side lead terminal separately from the lead frame to facilitate local heating, thereby facilitating the connection process between the half-covered diode and the terminal plate. . Even when the half-coated diode and the terminal plate are attached and connected by pressure contact, it is preferable that the half-covered diode has a lead terminal from the viewpoint of simplifying the pressure contact structure.

  The number of diode chips constituting the half-covered diode may be single or plural. That is, a plurality of diode chips may be arranged on a single lead frame. From the viewpoint of economy and the like, the number of the diode chips is preferably singular.

  The semi-covered diode 11 has a through hole 24 that penetrates the cover body 26 and the lead frame 21, and is fixed to the terminal board through a fixing screw 25 in the through hole 24.

  With reference to FIG. 2 and FIG. 6, the protrusion part 331 and the notch part 332 are alternately formed in the side edge of the terminal board. A pair of adjacent terminal plates (in FIG. 6, the intermediate terminal plate 33a and the intermediate terminal plate 33b) are arranged in a state where the protruding portion 331 and the cut portion 332 are engaged with each other. The protruding portion 331 has a through hole that receives the tip portion of the P-side lead terminal and the tip portion of the N-side lead terminal of the semi-coated diode 11.

  The protruding portion 331c of the intermediate terminal plate 33a and the protruding portion 331d of the intermediate terminal plate 33b are close to each other, and the tip portion of the P-side lead terminal and the tip portion of the N-side lead terminal of the single half-covered diode 11d are It is inserted into each through hole and connected by soldering. Similarly, the protruding portion 331a of the intermediate terminal plate 33a and the protruding portion 331b of the intermediate terminal plate 33b are close to each other, and the single half-covered diode 11c is similarly connected.

  Since the pair of adjacent terminal plates are arranged in a state where the protruding portion and the cut portion are engaged with each other, the plane area of the terminal box 2 can be saved. Furthermore, it becomes easy to arrange the entire lower surface of the lead frame in contact with the terminal board.

  The shape of the protruding portion and the cut portion is not limited to a square, and may be a triangle, a waveform, or the like.

  It is preferable that the plurality of half-covered diodes connected in parallel between the pair of terminal plates are arranged at regular intervals. The distance is preferably 1 mm or more from the standpoint that if the distance is too close, conduction may occur due to inadvertent movement or assembly processing becomes difficult. When the interval is increased, a considerable opening occurs in the environment such as the temperature of the plurality of half-covered diodes, and a considerable opening occurs in the current flowing through the plurality of half-covered diodes. From the viewpoint of suppressing overheating of the individual diodes, and from the viewpoint of avoiding the terminal plate from becoming larger, and hence the terminal box from becoming unnecessarily large, the interval is usually 6 mm or less, preferably 5 mm or less, More preferably, it is 4 mm or less.

  Furthermore, a plurality of half-covered diodes connected in parallel between a pair of terminal plates can be made to have the same temperature environment of the half-covered diodes, and the currents flowing through the plurality of half-covered diodes are made equal. From the viewpoint of suppressing overheating, two is preferable.

  2 and 6, the terminal plate has an output electrode receiving portion 336, a half-covered diode receiving portion 338, and a connecting portion 337 for connecting the output electrode receiving portion 338 and the half-covered diode receiving portion 336. Yes. The cross-sectional area of the connecting portion 337 is smaller than the cross-sectional area of the half-covered diode receiving portion 338.

  Considering the promotion of heat dissipation of the half-covered diode, it is preferable to increase the size of the terminal plate that plays the role of the heat dissipation plate, so that the heat capacity of the terminal plate inevitably increases. On the other hand, the terminal plate is used to connect the output electrodes, and when the connection processing is performed by thermal processing means (for example, soldering), the output electrode receiving portion needs to be locally heated.

For this reason, the cross-sectional area of the connecting portion 337 is reduced to facilitate local heating of the output electrode receiving portion 336. As a means for reducing the cross-sectional area, as shown in the figure, one through hole may be provided, a plurality of through holes may be provided, a cut portion may be provided from one side or both sides, and the wall thickness may be reduced. Also good. The cross-sectional area of the connecting portion is not particularly limited as long as it does not hinder electrical conduction and heat transfer is hindered. For example, the cross-sectional area may be 2 mm ² or more. Actually, the cross-sectional area may be determined in consideration of the strength of the connecting portion.

A plurality of half-covering diode, when each is intended to include a single diode chip, the planar area of the intermediate terminal board QMM ^2, if planar area Rmm ² single diode chip constituting the half-covering diodes, Q And R preferably satisfy the relationship of the formula (1).
Q ≧ 50R Formula (1)
More preferably, Q and R preferably satisfy the relationship of formula (2).
Q ≧ 60R Formula (2)

  Unlike the external connection terminal board that transmits heat by transmitting the external connection cable, the intermediate terminal board needs to further promote heat dissipation to the environment. This is to promote the heat dissipation of the diode. Further, the heat dissipation performance of the intermediate terminal board is mainly determined by the area.

  Here, when the intermediate terminal plate includes the connecting portion 337 described above, the area of the output electrode receiving portion and the connecting portion is excluded in calculating the planar area Q of the intermediate terminal plate. On the other hand, the area of the protrusion 331 is included in the plane area Q of the intermediate terminal plate.

  In this embodiment, the dimensions of the terminal board are as follows.

N side external connection terminal board 32a
Maximum length (including caulking part for connecting external connection cable): 76 mm,
Maximum length of the portion excluding the output electrode receiving portion and the connecting portion (including the caulking portion for connecting the external connection cable): 63 mm
Maximum width: 29mm
Output electrode receiving part width: 15 mm
Through hole in the connecting part: length 2mm, width 11mm
Thickness: 0.8mm
Copper plate

P side external connection terminal board 32b
Maximum length (including caulking part for connecting external connection cable): 76 mm,
Maximum length of the portion excluding the output electrode receiving portion and the connecting portion (including the caulking portion for connecting the external connection cable): 63 mm
Maximum width: 22mm
Output electrode receiving part width: 15 mm
Dimensions of the through hole in the connecting part: 2mm in length and 11mm in width
Thickness: 0.8mm
Copper plate

Intermediate terminal plate 33a, intermediate terminal plate 33b
Maximum length: 83mm,
Maximum length of half-covered diode receiving part: 70mm
Maximum width: 38mm
Output electrode receiving part width: 15 mm
Through hole in the connecting part: length 2mm, width 11mm
Thickness: 0.8mm
Copper plate In this example, the plane area of the intermediate terminal plate is 1810 mm ² .

  A method for attaching the terminal box 2 will be described. The terminal box 2 is temporarily fixed to the back surface of the solar cell module through the output electrode 7 through the through portion 36. Each of the plurality of output electrodes 7 is soldered to the output electrode receiving portion 336 of one terminal board. Thereafter, the cavity of the terminal box is filled with silicon resin as necessary, and a lid is attached to the terminal box. Silicone resin is used for the purpose of waterproofing the terminal box.

  Although the terminal box etc. concerning one embodiment were explained above, the terminal box etc. concerning the present invention are not limited to the embodiment concerned. For example, in the terminal box according to the present invention, the number of intermediate terminal boards may be zero, or three or more.

<Example 1>
Using a terminal box having three terminal plates simplified as shown in FIG. 7, two half-covered diodes were connected between the terminal plates, and Tj (junction temperature) of the diodes when current was applied was measured. A simulated output electrode 71 was connected to the terminal board by soldering. The dimensions of the simulated output electrode 71 were 100 mm in length, 6 mm in width, and 0.4 mm in thickness.

  The half-coated diodes are those shown in FIGS. 3, 4 and 5 (hereinafter, the type of the half-coated diodes is indicated as “SI”), and the main dimensions are as follows.

Lead frame Maximum thickness: 2mm
Area of the portion having a thickness of 2 mm: about 185 mm ²
Maximum coating thickness: 5mm
The size of the diode chip was 4 mm × 6 mm square.
The N-side external connection terminal plate 32a and the P-side external connection terminal plate 32b are the same as those described with reference to FIG. 2, and the intermediate terminal plate 33c is the same as the intermediate terminal plate 33a described with reference to FIG. Are the same. Note that Q = 72.4R.

The test method was as follows.
(1) Vf and Ir of each half-covered diode were measured in the state of being placed and connected to the terminal box.
(2) A thermocouple was soldered to the upper part of the N-side lead terminal (portion close to the cover) of each half-covered diode. In this example, the temperature of the N-side lead terminal was regarded as the junction temperature of the diode (the same applies to Examples 2 to 4 and Comparative Examples 1 to 4).
(3) The inner space of the terminal box was filled with silicon resin (KE200 manufactured by Shin-Etsu Chemical Co., Ltd.).
(4) The silicon resin was dried by leaving it at room temperature for 24 hours.

(5) The terminal box was covered. At this time, the end portion of the simulated output electrode protruding from the terminal box was left as it was.
(6) The terminal box was placed in a constant temperature bath at 75 ° C., and a current of 10 A (ampere) was applied for 1 hour from the DC power supply device through the external connection cable. During the energization time, the temperature was measured with a thermocouple, and the maximum temperature was taken as the measured value of Tj.
(7) The terminal box was taken out of the thermostat, allowed to cool to room temperature, and then Vf and Ir of each half-covered diode were measured in the state of being placed and connected to the terminal box. The measured values of Example 1 are shown in Table 1.

  In the above (1) and (7), the Vf measurement was a value measured at 10 A energization, and the Ir measurement was a value measured at 600 V (volt) application, both of which were measured at a pulse of 2 ms. As a result of comparing the measured values of (1) and (7), the function of each half-coated diode used in the test was not destroyed even after 10 A for 1 hour. In each of Examples 2 to 4 and Comparative Examples 1 to 4, the function of each diode was not destroyed even after 10 A for 1 hour.

<Comparative Example 1>
Using a terminal box having three terminal plates simplified as shown in FIG. 8, one half-covered diode was connected between the terminal plates, and the Tj of the diode when current was applied was measured.
The terminal box was the same as in Example 1. Further, the half-coated diode was the same (SI) as used in Example 1. The test method was also the same as in Example 1. The measured values of Comparative Example 1 are shown in Table 1.

<Example 2>
The same test as in Example 1 was performed except that the type of the semi-coated diode was changed.
The tested semi-coated diode (hereinafter, the type of the semi-coated diode is indicated as “PA”) has a lead frame whose plane size is larger than the plane size of the cover, and a part of the lead frame including the through hole is Both the upper and lower surfaces are exposed. The main dimensions were as follows.

Lead frame Maximum thickness: 1.2mm
Area of the portion having a thickness of 1.2 mm: about 150 mm ²
Area of uncovered portion on both upper and lower surfaces: 63.5 mm ²
Maximum coating thickness: 4.5mm
The size of the diode chip: 5 mm × 5 mm square. Note that Q = 72.4R.

  The measured values of Example 2 are shown in Table 1.

<Comparative example 2>
The same test as Comparative Example 1 was performed except that the half-coated diode PA was used. The measured values of Comparative Example 2 are shown in Table 1.

<Example 3>
Using a terminal box having four terminal plates simplified as shown in FIG. 9, two half-covered diodes were connected between the terminal plates, and Tj of the diodes when current was applied was measured.

  The N-side external connection terminal plate 32a, the P-side external connection terminal plate 32b, and the intermediate terminal plates 33a and 33b are the same as those described with reference to FIG. Other measurement conditions and methods were the same as in Example 1. The measured values of Example 3 are shown in Table 2.

<Comparative Example 3>
Using a terminal box including four terminal plates simplified as shown in FIG. 10, one half-covered diode was connected between the terminal plates, and Tj of the diode when current was applied was measured. The terminal box was the same as in Example 3. The half-covered diode was the same (SI) as used in Example 1. The test method was also the same as in Example 1. The measured values of Comparative Example 3 are shown in Table 3.

<Example 4>
The test was performed under the same conditions and in the same manner as in Example 3 except that the semi-coated diode (SI) was replaced with the semi-coated diode (PA). The measured values of Example 4 are shown in Table 2.

<Comparative example 4>
The test was performed under the same conditions and in the same manner as in Comparative Example 3 except that the semi-coated diode (SI) was replaced with the semi-coated diode (PA). The measured values of Comparative Example 4 are shown in Table 2.

  In Example 1-4, a lower Tj was measured for any half-coated diode compared to Comparative Example 1-4.

  The terminal box for solar cell modules according to the present invention can be used, for example, for extracting power from the solar cell module. The solar cell system according to the present invention can be used for photovoltaic power generation, for example.

It is explanatory drawing of a solar cell system. 3 is a plan view of a terminal box 2. FIG. 3 is an explanatory plan view of a half-covered diode 11. FIG. FIG. 4 is a cross-sectional explanatory view of the half-coated diode 11 taken along line A-A ′ in FIG. 3. FIG. 4 is a cross-sectional explanatory view of the half-coated diode 11 taken along line B-B ′ in FIG. 3.

It is explanatory drawing, such as the shape of intermediate terminal boards 33a and 33b It is a schematic explanatory drawing of the terminal box used in Example 1, and has shown arrangement | positioning of the half-clad diode E1-E4. It is a schematic explanatory drawing of the terminal box used by the comparative example 1, and has shown arrangement | positioning of half-clad diode R1-R2. It is a schematic explanatory drawing of the terminal box used in Example 3, and has shown arrangement | positioning of the half-clad diode E11-E16. It is a schematic explanatory drawing of the terminal box used by the comparative example 3, and has shown arrangement | positioning of the half-clad diode R11-R13.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Solar cell system 2 Terminal box 6 Solar cell module 7 Output electrode 10 Case 11 Half-covered diode 12 Diode chip 13 P-type semiconductor 15 P-side lead terminal 17 N-type semiconductor 19 N-side lead terminal 21 Lead frame 22 Lower surface of the lead frame 26 Covering body

32a, 32b External connection terminal plates 33a, 33b, 33c Intermediate terminal plates 41, 43 External connection cable 71 Simulated output electrode 331 Protruding portion 332 Cut portion 336 Output electrode receiving portion 337 Semi-covered diode receiving portion 338 Connecting portion

Claims (3)

A plurality of terminal plates connected in a one-to-one correspondence to a plurality of output electrodes of the solar cell module, and a rectifying element disposed and connected between at least a pair of terminal plates among the plurality of terminal plates; A solar cell module terminal box that relays the solar cell module and the external connection cable,
The rectifying element includes a lead frame and a diode chip. The diode chip has a flat plate shape in which a flat plate N type semiconductor is bonded to a flat plate P type semiconductor, and the lead frame has a flat plate shape having conductivity. A plurality of semi-covered diodes, wherein the upper surface of the lead frame and the N-type semiconductor electrode of the diode chip are arranged in contact with each other, and the upper surface and the side surface of the diode chip are coated with a resin. And a plurality of the half-coated diodes are electrically connected in parallel,
In the terminal box for the solar cell module , the entire surface of the lower surface of the lead frame of the half-coated diode is in contact with the terminal plate,
The pair of terminal boards are provided with a protruding portion and a cut portion at a location where the rectifying element is disposed, and the protruding portion and the cut portion are arranged in mesh with each other,
The half-covering diode has a P-side lead terminals extending from the P-type semiconductor electrode, the N-side lead terminal which extends through the lead frame from the N-type semiconductor electrode, the P The side lead terminal and the N side lead terminal protrude from the same side surface of the coating resin,
The P-side lead terminal and the N-side lead terminal are connected to the protruding portion of one terminal plate and the protruding portion of the other terminal plate, which are adjacent to each other, of the pair of terminal plates. Battery module terminal box. In the terminal box for solar cell modules described in claim 1,
There are n (n is a positive integer greater than or equal to 3) pieces of the plurality of terminal plates, the n number of terminal plates being two external connection terminal plates to which external connection cables are connected, and (n-2) pieces. Middle terminal board,
The (n-2) intermediate terminal plates are provided with and connected to the plurality of half-covered diodes,
Each of the plurality of half-coated diodes comprises a single diode chip;
The intermediate QMM 2 the planar area of the terminal ^plate, wherein the single diode chip planar area Rmm ² solar cell module terminal box that satisfies the relationship of formula (1) constituting the half-covering diode .
Q ≧ 50R Formula (1) In solar cell systems,
The solar cell system containing a solar cell module and the terminal box for solar cell modules in any one of Claims 1 thru | or 2.

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