JP2607314B2 - Interconnector for solar cell - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an interconnector for a solar cell for space development.

[0002]

2. Description of the Related Art Conventionally, there are a three-dimensional interconnector and a planar interconnector for interconnecting solar cells for space development mounted on an artificial satellite.

[0003] These interconnectors are provided with three-dimensional or planar stress reliefs, respectively, to absorb and reduce mechanical or thermal stress in outer space.

FIG. 6 is a plan view showing an example of a conventional flat interconnector. The flat type interconnector 3 includes a back electrode connecting portion 33, a stress relief portion 30, and a front electrode connecting portion. The stress relief portion 30 is a planar type, and notches 31 and 32 for stress relaxation are formed on the front electrode connection side and the adhesive connection side, respectively. The back electrode connection part 33 and the front electrode connection part 34 have a mesh structure. FIG. 7 is an enlarged view of a portion A in FIG. 6, and shows a mesh having a mesh structure. The arrow a in the figure is the length direction of the mesh hole, and coincides with the solar cell connection direction (arrow b in FIG. 6).

FIG. 4 is a sectional view of a general solar cell paddle. The back electrode connecting portion 33 of the flat interconnector 3 is connected to the lower side of the solar cell 71 and is adhered to the substrate 9 by the adhesive 8, and the front electrode connecting portion 34 is connected to the front electrode of the solar cell 72. I have. In this way, the solar cells are connected in series on the substrate.

FIG. 5 is a plan view of a series connection of solar cells. Two planar interconnectors 3 are used for each solar cell connection. The back electrode connection part 33 is connected to the lower side of the solar cell 71 by the adhesive 8, and the front electrode connection part 34 is connected to the solar cell 72. The adhesive 8 is applied so as not to overlap with the stress relief portion.

[0007] With the above configuration and connection method, the interconnector for a solar cell is used in the outer space, and the notch in the stress relief portion absorbs the stress generated by the temperature change between the solar cells in the space environment. And prevent damage to the interconnector.

[0008]

However, in the case of the above-mentioned connection method, the application of the adhesive cannot be controlled completely,
Often, the adhesive spills out into the stress relief area. This solar cell is used for space development and is mounted on an artificial satellite or the like. In space environments, low temperatures below -100 ° C. are often encountered, in which case the modulus of the adhesive increases from about 2 × 10 ² N / cm ² to 6 × 10 ⁵ N / cm ² . When the elastic modulus of the adhesive greatly increases, the protruding adhesive fixes the notch of the stress relief, and reduces the stress absorption function inherent in the stress relief. At such a low temperature, in the air environment, stress due to temperature cycling is repeatedly encountered, and the interconnector is electrically and mechanically opened due to the reduced stress absorption function of the stress relief, which requires the solar cell paddle. Power cannot be generated.

Further, even when the adhesive does not protrude into the stress relief portion, the end of the notch of the stress relief portion where stress concentrates may start to be damaged for a long time, and the open state of the interconnector may occur. It is required to extend the life of the interconnector.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a long-life interconnector for a photovoltaic cell by reducing a decrease in the stress absorbing function of a stress relief portion due to various causes.

[0011]

According to the present invention, there is provided a back electrode connecting portion connected to a back electrode of a solar cell, a front electrode connecting portion connected to a front electrode of another solar cell, and the back electrode. A plurality of solar cells are connected in series on a substrate by the back electrode connection part and the front electrode connection part, and are formed of a stress relief part between the connection part and the front electrode connection part. In a solar cell interconnector having an electrode connection portion and the front electrode connection portion having a mesh structure, and the stress relief portion having a plate structure in which two notches are formed on an adhesive connection side and a front electrode connection side, On the front electrode connection side of the stress relief portion, an auxiliary notch having a short length in the same direction as the notch on the adhesive connection side is formed, and the two notches and the two notches of the stress relief portion are formed. Portion excluding the periphery of the auxiliary notches, longitudinal direction, characterized in that the mesh structure composed of vertical openings in the longitudinal direction of the notch.

[0012]

In the interconnector for a solar cell according to the present invention, the length direction of the mesh opening is the same as the length of the notch except for the periphery of the notch of the stress relief portion which absorbs and relieves mechanical or thermal stress in outer space. Mesh structure perpendicular to the vertical direction.

The mesh absorbs the stress concentrated at the end of the notch, thereby reducing the load on the notch, making it difficult for the notch end to break, and delaying the occurrence of the open state of the interconnector. Furthermore, the auxiliary notch in the same direction as the notch on the adhesive connection side is provided on the front electrode connection side, so even if the notch on the adhesive connection side is fixed due to variation in adhesive application, the auxiliary notch functions and absorbs stress. It compensates for the reduced function of stress relief and prevents the occurrence of the open state of the interconnector.

[0014]

FIG. 1 is a plan view showing an interconnector for a solar cell according to an embodiment of the present invention. This interconnector has a planar stress relief portion.

The solar cell interconnector 1 includes a front electrode connecting portion 21, a back electrode connecting portion 22, and a stress relief portion 10. The front electrode connecting portion 21 and the back electrode connecting portion 22 have the same mesh structure as that of FIG. It has become. A notch 12 and an auxiliary notch 14 are formed on the front electrode connection side of the stress relief portion 10, and a notch 13 is formed on the adhesive connection side. An auxiliary bridge 16 having a width of about several μm is provided at an open portion of the notch 13. Notches 12, 13,
The peripheral portion 11 of the plate 14 has a plate shape, and the other portion 15 has a mesh structure. FIG. 2 is an enlarged view of the mesh structure of the stress relief portion, and the opening direction of the mesh is formed so that its length direction (arrow A) is perpendicular to the length direction of the notch (arrow B). Reference numeral 8 denotes an adhesive when the adhesive is adhered to the solar cell, and an area 8 'indicated by a two-dot chain line is an adhesive when the adhesive protrudes.

The apparent elastic modulus of the stress relief portion is reduced by the mesh structure of the portion 15 (FIG. 2) in FIG. 1 and a part of the stress to be absorbed by the stress relief portion is absorbed by the mesh, and the notch is formed. The stress concentration on the end portions 12 and 13 is reduced.

The auxiliary bridge 16 is for preventing the notch 13 from being opened. If the control of the adhesive application is good (adhesive 8) and a normal solar battery paddle assembly is completed, the space environment is not changed. The auxiliary bridge 16 breaks due to stress from the lower temperature cycle and the notch 13 performs its normal stress absorbing function. If the control of the application of the adhesive is poor (adhesive 8 ′), the adhesive overlaps the notch 13, and the elastic modulus of the adhesive becomes 1 due to a low temperature environment of −100 ° C.
Notch 13 is not opened and the stress absorbing function is greatly reduced. At this time, the auxiliary notch 14 performs a part of the stress absorbing function, and remarkably reduces the stress absorbing function.

FIG. 3 is a graph of experimental data showing the number of crack generation cycles at the ends of the notches 12 and 13 of the solar cell interconnector. The vertical axis represents the PP displacement corresponding to the magnitude of the stress absorbed by the notch 12 or 13, and the horizontal axis represents the crack (damage) at the end of the notch 12 or 13.
Represents the number of cycles corresponding to the number of stress loads (the fatigue life of the interconnector) until the occurrence of. It can be seen that as the PP displacement decreases, the fatigue life of the interconnector increases exponentially. That is, if the stress to be absorbed by the notch of the stress relief portion is reduced as much as possible, the fatigue life of the interconnector can be effectively extended.

[0019]

As described above, according to the present invention, except for the peripheral portion of the notch in the stress relief portion of the solar cell interconnector, the length of the mesh opening is perpendicular to the length of the notch. Due to the structure, the mesh can absorb the stress concentrated at the end of the notch, and the burden on the notch can be reduced. Therefore, the notch end is less likely to break, and the occurrence of the open state of the interconnector can be delayed. Furthermore, by providing an auxiliary notch in the same direction as the notch on the adhesive connection side on the front electrode connection side,
When the notch on the adhesive connection side is fixed due to the variation in the application of the adhesive, the auxiliary notch functions to absorb the stress and compensate for the reduced function of the stress relief.

Therefore, the fatigue life of the interconnector is prolonged, and the reliability of the solar cell paddle can be improved.

[Brief description of the drawings]

FIG. 1 is a plan view of a solar cell interconnector according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a mesh structure of a stress relief portion of the solar cell interconnector.

FIG. 3 is a notch 1 of the solar cell interconnector.
It is a graph of the experimental data showing the crack generation cycle number in the end part of 2 and 13.

FIG. 4 is a sectional view of a general solar battery paddle.

FIG. 5 is a plan view of a series connection of solar cells.

FIG. 6 is a plan view showing an example of a conventional flat interconnector.

FIG. 7 is an enlarged view of a portion A in FIG. 6;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Interconnector for solar cells 10 Stress relief part 12, 13 Notch 14 Auxiliary notch 21 Front electrode connection part 22 Back electrode connection part 8 Adhesive 9 Substrate

Claims (1)

(57) [Claims] 1. A back electrode connecting part connected to a back electrode of a solar cell, a front electrode connecting part connected to a front electrode of another solar cell, the back electrode connecting part and the front electrode connecting part. A plurality of solar cells are connected in series on a substrate by the back electrode connection part and the front electrode connection part, and the back electrode connection part and the front electrode connection are formed. The part is a mesh structure,
In the solar cell interconnector having a plate structure in which the stress relief portion has a plate structure in which two notches are formed on an adhesive connection side and a front electrode connection side, a notch on the adhesive connection side is provided on the front electrode connection side of the stress relief portion. An auxiliary notch having a short length in the same direction as that of the notch, and a portion of the stress relief portion excluding the two notches and the periphery of the auxiliary notch has an opening having a length direction perpendicular to the length direction of the notch. An interconnector for a solar cell, characterized by having a mesh structure composed of: