Solar cell module

Abstract

A solar cell module (1) has a solar cell panel (2), wiring (4), and a bypass diode device (5). The wiring (4) extends along a side surface (231a1) of the solar cell panel (2). The bypass diode device (5) has a housing (51) and a bypass diode (52) housed in the housing (51), and is positioned at a position overlapping the wiring (4) in a plan view seen from a direction perpendicular to the solar cell panel (2).

Description

solar cell module

[0001] SUMMARY OF THE INVENTION The disclosed embodiments relate to solar cell modules.

[0002] In recent years, solar power generation has become increasingly popular as a renewable energy source. Current solar cell modules usually have a junction box on the backside.

[0003] The junction box contains bypass diodes that protect the solar cells by bypassing the current when a problem occurs, such as when the solar cell module is shaded (see, for example, Patent Document 1).

[0004] JP 2015-185784 A

[0005] A solar cell module according to one aspect of the embodiment includes a solar cell panel, wiring, and a bypass diode device. The wiring extends along a side surface of the solar cell panel. The bypass diode device includes a housing and a bypass diode housed in the housing, and is positioned so as to overlap with the wiring in a plan view seen from a direction perpendicular to the solar cell panel.

[0006] FIG. 1 is a plan view showing an example of the configuration of a solar cell module according to an embodiment. FIG. 2 is a cross-sectional view taken along the line II-II in FIG. 1. FIG. 3 is a side view showing an example of the arrangement of bypass diode devices. FIG. 4 is a side view showing another example of the arrangement of bypass diode devices. FIG. 5 is a cross-sectional view showing an example of a connection portion between a bypass diode device and a second wiring. FIG. 6 is a cross-sectional view showing another example of a connection portion between a bypass diode device and a second wiring. FIG. 7 is a cross-sectional view showing another example of a connection portion between a bypass diode device and a second wiring.

[0007] Hereinafter, a mode for carrying out a solar cell module according to the present disclosure (hereinafter referred to as an "embodiment") will be described in detail with reference to the drawings. Note that the solar cell module according to the present disclosure is not limited to the embodiment.

[0008] Furthermore, in the following embodiments, expressions such as "constant," "orthogonal," "perpendicular," or "parallel" may be used, but these expressions do not necessarily mean "constant," "orthogonal," "perpendicular," or "parallel" in the strict sense. In other words, the above expressions allow for deviations due to, for example, manufacturing precision, installation precision, etc.

[0009] In addition, in the drawings referred to below, for ease of understanding, an orthogonal coordinate system may be shown in which the X-axis direction, Y-axis direction, and Z-axis direction, which are perpendicular to each other, are defined, and the positive Z-axis direction is the vertically upward direction.

[0010] First, the configuration of a solar cell module according to an embodiment will be described with reference to Figures 1 and 2. Figure 1 is a plan view showing an example of the configuration of a solar cell module according to an embodiment. Figure 2 is a cross-sectional view taken along the line II-II in Figure 1.

[0011] As shown in FIGS. 1 and 2 , the solar cell module 1 includes a solar cell panel 2 , a first wiring 3 , a second wiring 4 (an example of wiring), and a bypass diode device 5 .

[0012] The solar cell panel 2 has a configuration in which a first film 21, a first resin layer 22, a cell group 23, a second resin layer 24, and a second film 25 are laminated in this order. Note that the first film 21, the first resin layer 22, the second resin layer 24, and the second film 25 are not shown in Fig. 1.

[0013] The cell group 23 includes a plurality of series cell groups 231. Note that only one series cell group 231 is shown in FIG. 2. The series cell group 231 includes a plurality of cells 231a electrically connected in series. The series cell group 231 may include a portion of the cell group 23 in which the cells are connected in parallel. The cell group 23 is sometimes called a solar cell.

[0014] In the solar cell module 1 shown in Figure 2, the first film 21 side is the surface that receives sunlight. The second film 25 side is the side that faces the ground surface. The second film 25 side is also the side that is closer to the ground surface. The first film 21 and the second film 25 are made of, for example, EVA (ethylene vinyl acetate).

[0015] When the solar cell panel 2 is considered to be a laminate of the first film 21, the first resin layer 22, the cell group 23, the second resin layer 24, and the second film 25, the bypass diode device 5 may be arranged in the same layer as the cell group 23. In this case, the bypass diode device 5 may be arranged sandwiched between the first resin layer 22 and the second resin layer 24 together with the second wiring 4.

[0016] The bypass diode device 5 is preferably disposed around the cell group 23 within the solar cell module 1. By disposing the bypass diode device 5 around the cell group 23 within the solar cell module 1, the cell group 23 can be disposed in a concentrated manner within the plane, making it possible to obtain a highly efficient solar cell module 1.

[0017] The first wiring 3 is connected to the upper surface of each cell 231 a located at the end in the plane of the cell group 23 , and extends toward the second wiring 4 .

[0018] The second wiring 4 is positioned so as to extend along the side surface of the solar cell panel 2. The side surface of the solar cell panel 2 corresponds to the side surface 231a1 of each cell 231a located at the edge in the plane of the cell group 23, which is not adjacent to other cells 231a. The second wiring 4 is electrically connected to each first wiring 3 extending from each cell 231a located at the edge in the plane of the cell group 23. As a result, the second wiring 4 forms a common wiring that aggregates each first wiring 3. The second wiring 4 is also sometimes called a bus bar.

[0019] The second wiring 4 is separated into a first wiring portion 41 and a second wiring portion 42 located away from the first wiring portion 41 in the extension direction (here, the X-axis direction) of the second wiring 4. That is, a space 43 is formed in the middle of the second wiring 4, sandwiched between the first wiring portion 41 and the second wiring portion 42.

[0020] When the solar cell panel 2 is considered to be a laminate of the first film 21, the first resin layer 22, the cell group 23, the second resin layer 24, and the second film 25, the second wiring 4 may be arranged in the same layer as the cell group 23. In this case, the second wiring 4 may be arranged to be sandwiched between the first resin layer 22 and the second resin layer 24 together with the bypass diode device 5.

[0021] The bypass diode device 5 has a housing 51. The housing 51 houses a bypass diode 52. The bypass diode 52 is a junction of a P-type semiconductor and an N-type semiconductor.

[0022] The bypass diode device 5 is located at a position overlapping with the second wiring 4 in a plan view seen from a direction perpendicular to the solar cell panel 2 (here, the positive direction of the Z axis). Specifically, the bypass diode device 5 is located at a position overlapping with the space 43 of the second wiring 4.

[0023] If a junction box having bypass diodes were to be provided on the back surface (bottom surface) of the solar cell module 1, the junction box would protrude from the back surface (bottom surface) of the solar cell module 1, and the circuit having the bypass diodes and wiring would become larger.

[0024] In contrast, in the embodiment, the bypass diode device 5 is disposed on the line of the second wiring 4 that is disposed along the side surface of the solar cell panel 2. This allows the bypass diode device 5 to be disposed to the side of the solar cell panel 2, thereby reducing the amount of protrusion of the bypass diode device 5 from both the top and bottom surfaces of the solar cell module 1. As a result, with the solar cell module 1 according to the embodiment, the flatness of both the top and bottom surfaces of the solar cell module 1 can be maintained, and therefore the circuit having the bypass diodes 52 and the second wiring 4 can be made small and thin.

[0025] Furthermore, if the solar cell module 1 has a flat plate-type structure in which the bypass diode devices 5 are disposed to the side of the solar cell panel 2, it becomes possible to stack multiple solar cell modules 1 one on top of the other with no gaps in the stacking direction. Furthermore, if the solar cell module 1 has a flat plate-type structure, even when the solar cell modules 1 are stacked, the amount of protrusion at the position of the bypass diode devices 5 can be reduced, thereby reducing the occurrence of bending stress at the position of the bypass diode devices 5. This reduces the bulk (volume) when transporting multiple solar cell modules 1, thereby improving transportation efficiency.

[0026] 3 and 4, the arrangement of the bypass diode device 5 relative to the space 43 of the second wiring 4 will be described. FIG. 3 is a side view showing an example of the arrangement of the bypass diode device 5.

[0027] 3 , the bypass diode device 5 may be located above the space 43, spanning the first wiring portion 41 and the second wiring portion 42. The bottom surface of the bypass diode device 5 may be in contact with the upper surfaces of the first wiring portion 41 and the second wiring portion 42. The bypass diode device 5 may be bonded to the upper surfaces of the first wiring portion 41 and the second wiring portion 42, for example, by a conductive adhesive. That is, a conductive adhesive may be interposed between the bypass diode device 5 and the first wiring portion 41 and between the bypass diode device 5 and the second wiring portion 42.

[0028] In this way, the bypass diode device 5 is positioned above the space 43 across the first wiring portion 41 and the second wiring portion 42, thereby increasing the contact area between the electrode portion of the bypass diode device 5 and the first wiring portion 41 and the second wiring portion 42. This reduces the contact resistance between the bypass diode device 5 and the first wiring portion 41 and the second wiring portion 42.

[0029] FIG. 4 is a side view showing another example of the arrangement of the bypass diode device 5. In FIG.

[0030] 4 , the bypass diode device 5 may be sandwiched between the first wiring portion 41 and the second wiring portion 42 and positioned in the space 43. The side surface of the bypass diode device 5 may be in contact with an end surface of at least one of the first wiring portion 41 and the second wiring portion 42. The bypass diode device 5 may be bonded to an end surface of at least one of the first wiring portion 41 and the second wiring portion 42 by, for example, a conductive adhesive. That is, a conductive adhesive may be interposed between the bypass diode device 5 and at least one of the first wiring portion 41 and the second wiring portion 42.

[0031] In this way, by positioning the bypass diode device 5 in the space 43 sandwiched between the first wiring portion 41 and the second wiring portion 42, the height position of the back surface of the bypass diode device 5 can be made closer to the height position of the lower surface of the second wiring 4 along the thickness direction of the second wiring 4. This makes it possible to reduce the height from the lower surface of the second wiring 4 to the upper surface of the bypass diode device 5, thereby facilitating the reduction in height of the solar cell module 1.

[0032] 3 and 4 , when the length LN of the space 43 in the extension direction of the second wiring 4 (here, the X-axis direction) is defined as 1, the length LB of the bypass diode device 5 may be 0.7 or more and 1.3 or less. This improves the degree of freedom in arranging the bypass diode device 5 with respect to the space 43. For example, when the length LB of the bypass diode device 5 is greater than 1.0, i.e., longer than the length LN of the space 43, the arrangement shown in FIG. 3 can be used as the arrangement of the bypass diode device 5 with respect to the space 43. On the other hand, when the length LB of the bypass diode device 5 is smaller than 1.0, i.e., shorter than the length LN of the space 43, the arrangement shown in FIG. 4 can be used as the arrangement of the bypass diode device 5 with respect to the space 43.

[0033] 3 and 4 , when the thickness TP of the solar cell panel 2 (here, the thickness of the cell 231a) is taken as 1, the thickness TB of the bypass diode device 5 may be 0.2 or more and 1.1 or less. This makes it possible to reduce the amount of protrusion from both the top and bottom surfaces of the solar cell module 1 due to the thickness TB of the bypass diode device 5, even when the bypass diode device 5 is disposed to the side of the solar cell panel 2. As a result, it is possible to further reduce the height of the solar cell module 1.

[0034] Furthermore, when the width WL (see FIG. 1) of the second wiring 4 is 1 in plan view seen from a direction perpendicular to the solar cell panel 2 (here, the Z-axis direction), the width WB (see FIG. 1) of the bypass diode device 5 may be 0.7 or more and 1.3 or less. This makes it possible to reduce excess space on both sides of the second wiring 4 in the width direction even when the bypass diode device 5 is disposed at a position overlapping the second wiring 4 in plan view.

[0035] Next, the connection portion between the bypass diode device 5 and the second wiring 4 will be described with reference to Fig. 5 to Fig. 7. Fig. 5 is a cross-sectional view showing an example of the connection portion between the bypass diode device 5 and the second wiring 4.

[0036] 5, the first electrode member 13 is bonded to the upper surface of the bypass diode 52. Although not shown, the bypass diode 52 has a first terminal electrode on one surface thereof and a second terminal electrode on the other surface thereof.

[0037] As shown in FIG. 5, the bypass diode device 5 includes a conductor 53 in addition to a housing 51 and a bypass diode 52 .

[0038] The conductor 53 is an electrode for electrically connecting the bypass diode 52. The conductor 53 has an inner surface conductor portion 53a and an outer surface conductor portion 53b.

[0039] The inner conductor portion 53a is located on the inner surface of the bottom portion 51a of the housing 51. The inner conductor portion 53a has a portion (mounting portion) on which the bypass diode 52 is mounted. The inner conductor portion 53a is a member for fixing the bypass diode 52 to the housing 51.

[0040] The inner conductor portion 53a has a first electrode portion 53a1 and a second electrode portion 53a2. The first electrode portion 53a1 and the second electrode portion 53a2 are located spaced apart from each other on the inner surface of the bottom portion 51a of the housing 51. One of the first electrode portion 53a1 and the second electrode portion 53a2 serves as a mounting portion for the bypass diode 52. The other of the first electrode portion 53a1 and the second electrode portion 53a2, which is not the mounting portion for the bypass diode 52, serves as an electrode portion to which an external circuit for flowing current outside the housing 51 is electrically connected.

[0041] For example, when the second electrode portion 53a2 is a mounting portion for the bypass diode 52, the bypass diode 52 is disposed on the second electrode portion 53a2. The first terminal electrode of the bypass diode 52 is electrically connected to the second electrode portion 53a2, and the second terminal electrode of the bypass diode 52 is electrically connected to the first electrode portion 53a1 via the first electrode member 13 and the bonding wire 16.

[0042] The inner conductor portion 53a and the outer conductor portion 53b are connected by a through conductor portion 53c that penetrates the bottom portion 51a of the housing 51 in the thickness direction. The through conductor portion 53c has a plurality of through conductors 53c5. The plurality of through conductors 53c5 are electrically connected to the inner conductor portion 53a and also electrically connected to the outer conductor portion 53b.

[0043] Since the inner conductor portion 53a and the outer conductor portion 53b are connected by the through conductor portion 53c that penetrates the bottom 51a of the housing 51 in the thickness direction, the heat generated from the bypass diode 52 can be easily transferred to the opposite side of the mounting portion of the bypass diode 52 on the bottom 51a of the housing 51.

[0044] The outer surface conductor portion 53b is located on the outer surface of the bottom 51a of the housing 51. The outer surface conductor portion 53b has a third electrode portion 53b1 and a fourth electrode portion 53b2. The third electrode portion 53b1 and the fourth electrode portion 53b2 are located on the outer surface of the bottom 51a of the housing 51 at positions facing the first electrode portion 53a1 and the second electrode portion 53a2, respectively. That is, the third electrode portion 53b1 is located at a position facing the first electrode portion 53a1 across the bottom 51a of the housing 51. The fourth electrode portion 53b2 is located at a position facing the second electrode portion 53a2 across the bottom 51a of the housing 51.

[0045] The third electrode portion 53b1 and the fourth electrode portion 53b2 are formed in a film shape and are electrically connected to the first wiring portion 41 and the second wiring portion 42, respectively. The third electrode portion 53b1 and the fourth electrode portion 53b2 may be bonded to the upper surfaces of the first wiring portion 41 and the second wiring portion 42, for example, by a conductive adhesive.

[0046] The bypass diode device 5 is connected to the first wiring portion 41 and the second wiring portion 42 via the film-like third electrode portion 53b1 and the film-like fourth electrode portion 53b2, respectively, thereby reducing the thickness of the connection portion between the bypass diode device 5 and the second wiring 4. As a result, the height of the solar cell module 1 can be reduced.

[0047] The through conductor portion 53c may have a first through conductor portion 53c1 and a second through conductor portion 53c2. The first electrode portion 53a1 and the third electrode portion 53b1 may be electrically connected via the first through conductor portion 53c1. The second electrode portion 53a2 and the fourth electrode portion 53b2 may be electrically connected via the second through conductor portion 53c2. The first through conductor portion 53c1 and the second through conductor portion 53c2 may each be formed by a plurality of through conductors 53c5.

[0048] The inner conductor portion 53a and the outer conductor portion 53b are preferably connected by multiple through conductors 53c5, each having the same resistance value. A configuration in which multiple through conductors 53c5 with a diameter as shown in FIG. 6 are arranged in the bottom portion 51a between the inner conductor portion 53a and the outer conductor portion 53b is preferable. Instead of the above-described structure in which multiple through conductors 53c5 are closely spaced, multiple through conductors 53c5 may be integrated into a single large through conductor. A single through conductor makes it difficult to alleviate stress and strain between the bottom portion 51a and the through conductor due to differences in the thermal expansion coefficients and Young's moduli of the insulator (ceramic) and the conductor material (metal), increasing the likelihood of damage to the bottom portion 51a. In this case, as shown in FIG. 6, the through conductors 53c5 are preferably arranged not only directly below the bypass diode 52 but also outside the area directly below where the surrounding bypass diodes 52 are bonded.

[0049] The through conductor portion 53c has the first through conductor portion 53c1 and the second through conductor portion 53c2, each formed by a plurality of through conductors 53c5, and thus the surface area of ​​the through conductor portion 53c is increased, thereby improving the function of the through conductor portion 53c as a thermal conductor, thereby further improving heat dissipation from the through conductor portion 53c and the bottom 51a of the housing 51.

[0050] The area of ​​the third electrode portion 53b1 in a plan view is preferably larger than the area of ​​the region of the first penetrating conductor portion 53c1 in a plan view. The area of ​​the fourth electrode portion 53b2 in a plan view is preferably larger than the area of ​​the region of the second penetrating conductor portion 53c2 in a plan view. The area of ​​the third electrode portion 53b1 in a plan view may be larger than the area of ​​the first electrode portion 53a1 in a plan view. The area of ​​the fourth electrode portion 53b2 in a plan view may be larger than the area of ​​the second electrode portion 53a2 in a plan view. In this case, heat is likely to dissipate from the outer surface of the bottom 51a of the housing 51, opposite the portion where the bypass diode 52 is mounted.

[0051] A metal having high thermal conductivity and electrical conductivity is preferably used as the material of the conductor 53. The material of the conductor 53 may be, for example, at least one selected from the group consisting of tungsten, molybdenum, and copper.

[0052] The housing 51 may also have a flat bottom 51a on which the mounting portion of the bypass diode 52 and the inner conductor portion 53a are provided, and a bank portion 51b (wall member). The bank portion 51b is disposed on the peripheral edge of the bottom 51a of the housing 51 so as to circumferentially surround the mounting portion of the bypass diode 52 and the inner conductor portion 53a. A lid 56 is disposed on the upper surface of the bank portion 51b.

[0053] By forming the housing 51 into a cavity structure with the bank portion 51b and covering the bank portion 51b with the lid 56, it becomes unnecessary to resin-seal the bypass diodes 52 and bonding wires 16 arranged on the bottom portion 51a of the housing 51. This makes it more likely that the height of the solar cell module 1 can be reduced than when the bypass diodes 52 and bonding wires 16 are resin-sealed.

[0054] In this case, the area inside the bank portion 51b and the lid 56 where the bypass diode 52 is mounted may be filled with a gas such as air. Gas has lower thermal conductivity than the resin used for resin sealing. Therefore, heat generated from the bypass diode 52 is more likely to be transferred to the bottom portion 51a and the through conductor portion 53c. In the solar cell module 1, if the lid 56 is disposed in contact with the solar cell panel 2, heat from the bypass diode 52 is more likely to dissipate into the space on the back side of the solar cell panel 2.

[0055] It is preferable to use ceramics as the material for the housing 51. The ceramic used for the housing 51 may be, for example, a material containing, as a main component, one selected from the group consisting of alumina, aluminum nitride, mullite, zirconia, silica, forsterite, enstatite, silicon nitride, silicon carbide, and glass ceramics. This is because these materials can provide the housing 51 with high properties such as insulation, mechanical strength, moisture resistance, weather resistance, and chemical resistance. From the viewpoint of high thermal conductivity, it is particularly preferable to use ceramics containing aluminum nitride as a main component for the housing 51.

[0056] The material of the lid 56 may be a ceramic material of the same quality as the housing 51, as long as it is a dense material that can enhance airtightness, or a metal material. A metal material having a thermal expansion coefficient close to that of the housing 51 is preferable. An example of such a metal material is Kovar (Fe—Ni—Co). The thermal expansion coefficient of Kovar is 4.5 to 5×10 －６ / ℃.

[0057] FIG. 6 is a cross-sectional view showing another example of the connection portion between the bypass diode device 5 and the second wiring 4.

[0058] 6 , the bypass diode device 5 may further include a terminal 54 joined to the conductor 53 on the outside of the housing 51. The terminal 54 includes a first terminal portion 54 a and a second terminal portion 54 b. The first terminal portion 54 a and the second terminal portion 54 b are overlapped and joined to the third electrode portion 53 b 1 and the fourth electrode portion 53 b 2, respectively.

[0059] The first terminal 54a and the second terminal 54b are formed in a plate shape and are electrically connected to the first wiring portion 41 and the second wiring portion 42, respectively. The first terminal 54a and the second terminal 54b may be bonded to the upper surfaces of the first wiring portion 41 and the second wiring portion 42, for example, by a conductive adhesive.

[0060] The bypass diode device 5 is connected to the first wiring portion 41 and the second wiring portion 42 via the plate-shaped first terminal portion 54a and the plate-shaped second terminal portion 54b, respectively, thereby reducing the thickness of the connection portion between the bypass diode device 5 and the second wiring 4. Furthermore, the first terminal portion 54a and the second terminal portion 54b are located between the housing 51 of the bypass diode device 5 and the second wiring 4, thereby mitigating the stress that acts between the housing 51 and the second wiring 4 during thermal expansion. As a result, the height of the solar cell module 1 can be reduced and the possibility of damage to the bypass diode device 5 and the second wiring 4 can be reduced.

[0061] Furthermore, it is preferable that the thickness of each of the first terminal portion 54a and the second terminal portion 54b is thinner than the thickness of each of the first wiring portion 41 and the second wiring portion 42. This reduces the rigidity of the first terminal portion 54a and the second terminal portion 54b, thereby further alleviating the stress that acts between the housing 51 and the second wiring 4 during thermal expansion.

[0062] 6 , of the first terminal 54a and the second terminal 54b, the second terminal 54b connected to the fourth electrode 53b2, which is the external electrode on the bypass diode 52 side, is arranged so as not to overlap with the bypass diode 52 when the bypass diode device 5 is viewed from the side. Furthermore, the second terminal 54b is arranged so as not to overlap with any of the through conductors 53c5 when the bypass diode device 5 is viewed from the side. In other words, when the bypass diode device 5 is viewed from a perspective plan view, of the first terminal 54a and the second terminal 54b, the second terminal 54b connected to the fourth electrode 53b2, which is the external electrode on the bypass diode 52 side, is arranged so as not to overlap with the bypass diode 52. Similarly, when viewed from a perspective plan view, the second terminal 54b is arranged so as not to overlap with any of the through conductors 53c5. In this case, if the second terminal 54b is arranged so as not to overlap any of the through conductors 53c5, the distance from the bypass diode 52 to the second terminal 54b becomes longer, reducing the probability of defects occurring during mounting. In addition, since none of the through conductors 53c5 constituting the second through conductor 53c2 on the bypass diode 52 side overlaps with the second terminal 54b below, it becomes possible to improve heat dissipation from the housing 51.

[0063] On the other hand, the first terminal 54a located on the side of the first electrode 53a1 that is not the mounting portion for the bypass diode 52 may be arranged to overlap at least one of the plurality of through conductors 53c5 provided on the bottom 51a of the housing 51, when viewed from above. When the first terminal 54a is arranged to overlap at least one of the plurality of through conductors 53c5 on the side of the first electrode 53a1 that is not the mounting portion for the bypass diode 52, the distance between the through conductor 53c5 and the first electrode 53a1 is shortened, thereby making it possible to increase the conductivity therebetween. Note that when the area of ​​the housing 51 or the bottom 51a is small and the area occupied by the first through conductor 53c1 and the second through conductor 53c2 is high relative to the area of ​​the bottom 51a, the first terminal 54a and the second terminal 54b may be configured to overlap the through conductors 53c5 included in the first through conductor 53c1 and the second through conductor 53c2, respectively. In this case, the first terminal 54a and the second terminal 54b contribute greatly to heat dissipation at both terminals. In a structure in which the first terminal 54a and the second terminal 54b do not overlap with all of the through conductors 53c5 included in the first through conductor 53c1 and the second through conductor 53c2, the effects of stress and restraint force exerted by the first terminal 54a and the second terminal 54b on the bypass diode device 5 are reduced. In such a structure, the housing 51 and the bypass diode 52 are less likely to break, and the life of the bypass diode device 5 can be extended.

[0064] Furthermore, in the bonding between the first wiring portion 41 and the second wiring portion 42 to which the first terminal portion 54a and the second terminal portion 54b are bonded, the first wiring portion 41 does not have to be arranged so as to adhere to the entire lower surface of the first terminal portion 54a. The first wiring portion 41 may be arranged so as to adhere to a portion of the lower surface of the first terminal portion 54a, leaving a non-bonded portion on the lower surface. The second wiring portion 42 also does not have to be arranged so as to adhere to the entire lower surface of the second terminal portion 54b. The second wiring portion 42 may be arranged so as to adhere to a portion of the lower surface of the second terminal portion 54b, leaving a non-bonded portion on the lower surface. In this case, stress and restraint force can be reduced between the first terminal portion 54a and the second terminal portion 54b and the first wiring portion 41 and the second wiring portion 42, thereby reducing mechanical failures between the bypass diode device 5 and the first wiring portion 41 and the second wiring portion 42 and achieving a longer life. Such a configuration is advantageous when the bypass diode 52, the bottom portion 51a and the bank portion 51b forming the housing 51 are made smaller and thinner.

[0065] FIG. 7 is a cross-sectional view showing another example of the connection portion between the bypass diode device 5 and the second wiring 4.

[0066] 7 , the first terminal 54a and the second terminal 54b may protrude outward beyond the side surface of the housing 51. The first terminal 54a and the second terminal 54b may have portions 54a1 and 54b1 between their tips and the side surface of the housing 51 that do not overlap with the first wiring portion 41 and the second wiring portion 42. This allows flexibility to be imparted to the portions 54a1 of the first terminal 54a and the second terminal 54b that do not overlap with the first wiring portion 41 and the second wiring portion 42, thereby further reducing the stress that acts between the housing 51 and the second wiring portion 42 during thermal expansion.

[0067] As explained above, the disclosed bypass diode device 5 can be said to have the functionality of a junction box built into a low-profile package. In other words, the disclosed bypass diode device 5 is a wiring board that can incorporate the functionality of a junction box into a low-profile package. Here, low profile can also be rephrased as thin.

[0068] The disclosed bypass diode device 5 can also be enhanced by incorporating an IC function adjacent to the diode in a low-profile package. This function is to control the charging and discharging of a storage battery when the solar cell module 1 is equipped with an adjacent storage battery. This function is called a charge controller. A charge controller may not only have charging or discharging functions, but also a controller that combines these functions. In addition to the charging and discharging control and management functions, a charge controller should also have an overcharge prevention function (e.g., various voltage settings possible) including automatic output shutdown for battery protection (charging protection), and a discharge prevention function to prevent backflow of current to the solar cell panel 2. Another function is to convert the power (DC: direct current) generated and charged by solar power generation into power (AC: alternating current) suitable for home use. A DC / AC inverter is suitable for this purpose.

[0069] Furthermore, if the solar cell module 1 is equipped with an LCD monitor, it can display and record the amount of power supplied by the inverter, the amount of power generated by the solar panel, the battery voltage, etc. In this case, the charging and operating status of the solar cell panel can be confirmed and stored on a separately installed monitor.

[0070] The amount of power generated by a solar panel 2 is usually determined by voltage (V) x current (I), but by using a charge controller, it is possible to generate power only when the solar cell voltage and current are in a certain combination. In other words, the solar cell module 1 described above can be equipped with a function that controls the output voltage and current and selects the combination that always produces the maximum amount of power. This results in high conversion efficiency and stable power generation even on cloudy days when the amount of solar radiation varies.

[0071] Such a solar cell module 1 detects the balance between the power generation amount of the solar cell panel 2 and the capacity of the storage battery, and works to achieve the optimum performance (current value) at that time. As an additional function, it is desirable that the module can also control the self-power consumption of the semiconductor element itself.

[0072] Furthermore, according to the disclosed solar cell module 1, as described above, the bypass diode device 5 can be embedded together with the circuit board in the solar cell panel 2. The disclosed solar cell module 1 can be easily mounted on a mobility vehicle.

[0073] Examples of mobility vehicles include automobiles, motorcycles, bicycles, handcarts, tricycles (for small children), mobility vehicles for the elderly (maximum speed of approximately 5 km / h), wheelchairs for the disabled, wheelchairs for sports, carts (electric vehicles and engine vehicles) at amusement parks, wheelchairs at hospitals, airports, and train stations, trains, and airplanes. For example, the solar cell module 1 is suitable for objects with curved surfaces, such as the roof of an automobile. It is also suitable for motorcycles and bicycles, where it is difficult to install the solar cell panel 2 in a rectangular shape. It is also suitable for objects with curved shapes, such as the solar cell panel 2 itself. This is because the bypass diode device 5 is incorporated within the thickness of the solar cell panel 2, eliminating any unnecessary protrusions when the surface of the solar cell panel 2 is used as the reference plane. In other words, even with the bypass diode 52, both surfaces of the disclosed solar cell module 1 are parallel across the entire surface. In other words, both surfaces of the solar cell panel 2 are also parallel across the entire surface.

[0074] When a plurality of the above-described solar cell panels 2 or solar cell modules 1 are stacked, their surfaces overlap with no gaps between them. This reduces the likelihood of unnecessary space being created between the overlapping surfaces compared to solar cell panels 2 or solar cell modules 1 equipped with conventional junction boxes. This reduces the bulk (volume) of the solar cell panels 2 or solar cell modules 1 when transporting them. For example, this allows a greater number of solar cell panels 2 or solar cell modules 1 to be transported at one time on a means of transportation that is limited in its load capacity, such as a truck.

[0075] When a plurality of solar cell panels 2 or solar cell modules 1 are stacked, if the surfaces overlap each other without any gaps, there are no gaps, and therefore no buffer material is required to fill such gaps.

[0076] When multiple solar cell panels 2 or solar cell modules 1 are stacked, if their surfaces overlap without any gaps, the stacked solar cell panels 2 or solar cell modules 1 can be handled as a single unit. The integrated solar cell panels 2 or solar cell modules 1 form a structure that can mutually compensate for the mechanical strength of each other.

[0077] In this way, a solar cell panel 2 or solar cell module 1 in which multiple panels are stacked without gaps can be made highly durable against external loads such as impacts. The disclosed solar cell panel 2 or solar cell module 1 can improve the ease of transporting and installing the solar cell panel 2 or solar cell module 1, rather than the solar cell panel 2 or solar cell module 1 itself. This makes it possible to reduce incidental costs such as transportation and installation. This also leads to a reduction in the financial burden of initial installation of the solar cell module 1. For example, this is suitable for simple solar cell modules 1, such as adhesive-type modules.

[0078] As described above, if multiple solar cell panels 2 or solar cell modules 1 can be stacked without gaps, it is possible to reduce the workload and costs not only during installation but also when dismantling and transporting the solar cell modules 1 when they are no longer in use and are to be discarded. This also contributes to the reuse of the solar cell panels 2 or solar cell modules 1. This is because, in the case of solar cell panels 2 or solar cell modules 1, the series of tasks such as transportation, installation, and dismantling are almost the same regardless of whether the installation location is small or large, except for the time required, and therefore, in the case of small-scale solar cell modules 1 for home use, for example, it contributes more to the costs borne by individuals.

[0079] (Example) The correspondence between the prepared samples 1 and 2 and the drawings is as follows: Sample 1 corresponds to the solar cell module incorporating the bypass diode device shown in Fig. 5, and Sample 2 corresponds to the solar cell module incorporating the bypass diode device shown in Fig. 7.

[0080] First, a plurality of green sheets containing aluminum nitride powder were prepared.

[0081] Next, first and second pattern sheets for forming the housing were fabricated using these multiple green sheets. The first pattern sheet was fabricated using the following procedure. Specifically, through holes were formed in the first green sheet, and conductive paste was filled into these through holes to form raw through conductors (through conductor portions having multiple through conductors). Next, conductive paste was printed on both sides of the first green sheet on which the raw through conductors were formed to form conductive patterns. These conductive patterns become the internal conductor portion located on the internal surface of the bottom of the housing and having the mounting portion for the bypass diode, and the external conductor portion located on the back surface (external surface) of the bottom of the housing. The first green sheet on which the raw through conductors and conductive patterns were formed is referred to as the first pattern sheet.

[0082] On the other hand, rectangular through holes were formed in the second green sheet. The second green sheet with rectangular through holes formed therein is called a second pattern sheet. The second pattern sheet is a rectangular frame.

[0083] Next, a second pattern sheet having a rectangular frame was placed on the first pattern sheet to produce a green laminate having a cavity formed by a bottom and a bank. In the green laminate, the second pattern sheet having a rectangular frame was arranged to surround the conductor pattern on the first pattern sheet, which would become the inner conductor portion having the mounting portion for the bypass diode.

[0084] The green laminate obtained by the steps up to this point was produced in the form of a base laminate having many cavities formed therein, and therefore the green laminate was cut at a predetermined position to obtain individual laminate pieces each having one cavity.

[0085] The laminate of the individual pieces was fired to obtain a ceramic package that would serve as a housing. The firing conditions were the same as those normally used when using aluminum nitride powder (maximum temperature: 2000°C).

[0086] The bypass diodes used were rectangular parallelepiped type with terminal electrodes formed to cover almost the entire surface of both main surfaces. The bypass diode conductors (electrodes) were connected using a metal film and resin adhesive (solder was also acceptable). Kovar was used for the lid.

[0087] A bypass diode device (the bypass diode device shown in FIG. 5 ) was fabricated by mounting a bypass diode on a conductor (electrode portion) inside the housing. Another bypass diode device (the bypass diode device shown in FIG. 7 ) was fabricated in which the first terminal portion and the second terminal portion were joined to the external conductor portion (the third electrode portion and the fourth electrode portion) located on the rear surface (external surface) of the housing. Solder-plated copper was used as the material for the first terminal portion and the second terminal portion.

[0088] Next, each of these bypass diode devices was attached to a solar cell panel with the second wiring overlapping it, thereby fabricating solar cell modules of Samples 1 and 2.

[0089] The thickness TP of the solar cell panel of the fabricated solar cell module was 4 mm. The thickness TB (lid + housing) of the bypass diode device was 1 mm. The length LB of the bypass diode device was 7 mm. The width WB of the bypass diode device was 6 mm. The thickness TL of the second wiring was 0.4 mm. The width WL of the second wiring was 6 mm. The thicknesses of the first terminal portion and the second terminal portion were about half the thickness of the second wiring.

[0090] All of the solar cell modules fabricated were able to be made smaller and thinner than conventional structures using junction boxes.

[0091] Furthermore, for each solar cell module, a bypass diode device formed of a ceramic casing and lid was used, and the size was set as described above, so that a solar cell module equipped with a small bypass diode device could be obtained.

[0092] Furthermore, for all solar cell modules, the housing had a structure with multiple through conductors as conductors, which provided good heat dissipation, and no discoloration due to heat was observed in the part of the resin layer that was in contact with the bypass diode device.

[0093] In sample 2 (a solar cell module incorporating the bypass diode device shown in FIG. 7 ), when viewed from above, portions that do not overlap with the first wiring portion and the second wiring portion are provided between the tips of the first and second terminal portions and the side surface of the housing. Compared to sample 1 (a solar cell module incorporating the bypass diode device shown in FIG. 5 ), sample 2 showed a reduced degree of failure even after 1,000 temperature cycle tests (-20°C to 80°C) with a cycle period of 30 minutes. The degree of failure was determined by comparing the length of peeling between the lid and the resin layer of the bypass diode device.

[0094] As described above, the solar cell module (for example, solar cell module 1) according to the embodiment includes a solar cell panel (for example, solar cell panel 2), wiring (for example, second wiring 4), and a bypass diode device (for example, bypass diode device 5). The wiring extends along the side surface (for example, side surface 231a1) of the solar cell panel. The bypass diode device includes a housing (for example, housing 51) and a bypass diode (for example, bypass diode 52) housed in the housing, and is positioned so as to overlap with the wiring in a plan view seen from a direction perpendicular to the solar cell panel. This allows the circuit including the bypass diode and wiring to be made small and thin.

[0095] Further advantages and alternative embodiments may readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

[0096] REFERENCE SIGNS LIST 1 Solar cell module 2 Solar cell panel 3 First wiring 4 Second wiring 5 Bypass diode device 13 First electrode member 16 Bonding wire 21 First film 22 First resin layer 23 Cell group 24 Second resin layer 25 Second film 41 First wiring portion 42 Second wiring portion 43 Space 51 Housing 51a Bottom 51b Bank portion 52 Bypass diode 53 Conductor 53a Inner surface conductor portion 53a1 First electrode portion 53a2 Second electrode portion 53b Outer surface conductor portion 53b1 Third electrode portion 53b2 Fourth electrode portion 53c Through conductor portion 53c1 First through conductor portion 53c2 Second through conductor portion 53c5 Through conductor 54 Terminal 54a First terminal portion 54a1, 54b1 Portion 54b Second terminal portion 56 Lid 231 Series cell group 231a Cell 231a1 Side

Claims

1. A solar cell module comprising: a solar cell panel; wiring extending along a side surface of the solar cell panel; a bypass diode device having a housing and a bypass diode housed in the housing, the bypass diode device being positioned so as to overlap with the wiring in a plan view seen from a direction perpendicular to the solar cell panel.

2. The solar cell module according to claim 1, wherein the wiring has a first wiring section, a second wiring section located away from the first wiring section in the extension direction of the wiring, and a space sandwiched between the first wiring section and the second wiring section, and the bypass diode device is located in a position overlapping with the space in a plan view seen from a direction perpendicular to the solar cell panel.

3. The solar cell module according to claim 2, wherein the bypass diode device is positioned above the space, straddling the first wiring section and the second wiring section.

4. The solar cell module according to claim 2, wherein the bypass diode device is located in the space sandwiched between the first wiring portion and the second wiring portion.

5. The solar cell module according to claim 2, wherein the length of the bypass diode device is 0.7 to 1.3 when the length of the space in the extending direction of the wiring is 1.

6. The solar cell module according to claim 1, wherein the thickness of the bypass diode device is 0.7 to 1.1 when the thickness of the solar cell panel is 1.

7. The solar cell module according to claim 1, wherein when the width of the wiring is 1 in a plan view seen from a direction perpendicular to the solar cell panel, the width of the bypass diode device is 0.7 to 1.

3.

8. The solar cell module according to claim 2, wherein the bypass diode device has conductors that electrically connect the bypass diodes, the conductors having an inner conductor portion located on the inner surface of the bottom of the housing and on which the bypass diodes are mounted, and an outer conductor portion located on the outer surface of the bottom of the housing, the inner conductor portion having a first electrode portion and a second electrode portion that are located spaced apart from each other on the inner surface of the bottom of the housing, one of which serves as a mounting portion for the bypass diode, the outer conductor portion having a third electrode portion and a fourth electrode portion that are located on the outer surface of the bottom of the housing in positions facing the first electrode portion and the second electrode portion, respectively, the third electrode portion and the fourth electrode portion being formed in a film shape and electrically connected to the first wiring portion and the second wiring portion, respectively.

9. The solar cell module described in claim 8, wherein the bypass diode device has a terminal joined to the conductor, the terminal having a first terminal portion and a second terminal portion overlapping and joined to the third electrode portion and the fourth electrode portion, respectively, the first terminal portion and the second terminal portion being formed in a plate shape and electrically connected to the first wiring portion and the second wiring portion, respectively.

10. The solar cell module according to claim 9, wherein the thickness of each of the first terminal portion and the second terminal portion is thinner than the thickness of each of the first wiring portion and the second wiring portion.

11. A solar cell module as described in claim 9, wherein the first terminal portion and the second terminal portion protrude outward beyond the side surface of the housing and have a portion between their tip and the side surface of the housing that does not overlap with the first wiring portion and the second wiring portion.

12. The solar cell module according to claim 8, wherein the conductor has a through conductor portion that penetrates the bottom of the housing in the thickness direction and connects the inner conductor portion and the outer conductor portion.

13. The solar cell module described in claim 12, wherein the through conductor portion has a first through conductor portion and a second through conductor portion each formed by a plurality of through conductors, the first electrode portion and the third electrode portion are electrically connected via the first through conductor portion, and the second electrode portion and the fourth electrode portion are electrically connected via the second through conductor portion.

Images