JP2007165531A - Solar cell and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel battery cell or a fuel cell system capable of supplying fuel at the same concentration to each fuel battery cell at equal temperature and obtaining a uniform power generation situation. <P>SOLUTION: A solar cell comprises a transparent substrate 2, a solar cell element 3 that is provided with width that is narrower than the transparent substrate 2 on the transparent substrate 2, a water-repellent section 4 that is provided on the transparent substrate 2 and has a water-repellent effect, and a protective material 5 for covering the solar cell element 3 and the water-repellent section 4. The water-repellent section 4 is provided at least at one portion between the edge of the solar cell element 3 and that of the protective material 5. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a solar cell, and more particularly to a solar cell using silicon as a power generation layer.

  A solar cell is known in which a solar cell element containing silicon as a main component is formed on a transparent member, and the solar cell element is covered with a protective material such as EVA (ethylene-vinyl acetate copolymer).

  Such a solar cell is usually required to be usable outdoors for a long period of time. In order to be possible outdoors for a long period of time, durability under severe conditions such as ultraviolet rays, wind and snow, salt damage, acid rain, freezing, accumulation of dirt, generation of microorganisms, etc. is required. In particular, water intrusion is the most serious problem that affects the life of solar cells. If water enters the solar cell and comes into contact with the solar cell element or the wiring, there is a concern about the corrosion of the solar cell element or the wiring. It is desired to provide a solar cell that is unlikely to corrode due to water penetration.

  In relation to the above, Patent Document 1 discloses a solar cell module structure comprising a single or a plurality of solar cells, a wiring member for electrically connecting the solar cells or solar cells, and a structure for installing the solar cells. Discloses a solar cell module structure in which a hydrophilic member is disposed at least on the peripheral edge of the solar cell and / or the peripheral edge of the wiring member on the installation surface of the structure.

Patent Document 2 discloses a solar cell module in which a solar cell in which a plurality of solar cell elements are connected in series or in parallel is sealed with an adhesive resin sealing material between a front surface protection member and a back surface protection member. The outer periphery of the adhesive resin encapsulant at the periphery of the solar cell module has a weatherproof protective layer made of an organic polymer or a mixture of an organic polymer and the adhesive resin encapsulant, and Disclosed is a solar cell module characterized in that the outer peripheral portion of the weatherproof protective layer, the outer peripheral portion of the surface protective member, and the outer peripheral portion of the back surface protective member are formed in substantially the same plane in the side surface portion of the solar cell module Yes.
JP 2004-281600 A JP 2003-209273 A

  However, even when the technique for suppressing the intrusion into the solar cell module as described above is used, the solar cell element may be corroded when the solar cell is installed outdoors for a long period of time. The present inventors have discovered that such corrosion of solar cell elements is promoted by the following mechanism.

  1A and 1B are diagrams for explaining a mechanism for promoting corrosion of a solar cell element. In the example shown in FIG. 1A, two solar cell panels are connected in series. Each solar cell panel is fixed outdoors by a frame-shaped aluminum frame and installed outdoors. The cable taken out from each solar cell panel is connected to the inverter. The inverter is grounded.

  When such a solar cell panel is installed outdoors for a long time, corrosion of the solar cell element is likely to occur in the vicinity of the end of the solar cell panel and in a place where a negative voltage is generated with respect to the ground during power generation. I understood. From this, it is considered that the corrosion of the solar cell element is due to the following reason.

  FIG. 1B is a diagram showing a cross-section of the frame portion of each solar cell panel shown in FIG. 1A. In the solar cell panel, a solar cell element containing silicon, a protective material such as an EVA sheet, and a back sheet are formed in this order on one surface of the transparent member. Such a solar cell module is fixed by fitting an end portion into a fitting portion of an aluminum frame.

  Here, the protective material is disposed for the purpose of preventing water from entering, but the moisture permeability is not zero. Therefore, when left in a humid environment for a long time, water may permeate into the solar cell module. Water that has permeated into the solar cell module may condense at the interface between the protective material and the transparent substrate. In particular, when the drain hole provided for draining water is blocked by accumulated dirt, the solar cell module is exposed to a high humidity environment, and water enters the solar cell module. It becomes easy.

  On the other hand, even in the fitting portion of the frame, water may accumulate between the end portion of the solar cell module when exposed to the outdoors for a long time. The end portion of the solar cell module is submerged when water accumulates in the fitting portion of the frame.

  Since the amount of water condensed on the interface between the protective material and the transparent substrate is very small, even if it comes into contact with the solar cell element, this alone does not cause a major cause of corrosion of the solar cell. However, when the water condensed on the interface is continuous between the solar cell element and the end of the solar cell module and the end of the solar cell module is submerged as described above, A closed electric circuit of “water in the frame fitting part—condensed water—solar cell element—inverter—ground” is formed. In this state, when light enters the solar cell element and power generation is performed, a voltage difference is generated between the solar cell element and the ground. When the voltage difference is generated in the state where the closed electric circuit is formed, a ground fault current flowing from the solar cell element to the ground through water and the frame is generated. The generation of the ground fault current is due to the chemical (oxidation) reaction of the solar cell element accompanied by charge transfer. Since the water in contact with the solar cell element is alkaline, generation of a ground fault current is further promoted and the solar cell element is corroded.

  In addition, since a material containing aluminum may be used for the frame or the backsheet, water that enters the solar cell module may be alkaline water in which aluminum is present as ions. Alkaline water oxidizes solar cell elements containing silicon, which also accelerates corrosion of the solar cell elements.

  Moreover, since the adhesiveness with a protective material falls in the part which the solar cell element corroded, a protective material peels and the penetration | invasion of water is further accelerated | stimulated.

  That is, an object of the present invention is to provide a solar cell and a solar cell manufacturing method in which corrosion of the solar cell element due to water intrusion is suppressed.

  Moreover, in this invention, it aims at providing the solar cell and solar cell manufacturing method which suppress corrosion of a solar cell element by suppressing generation | occurrence | production of a ground fault electric current.

  Means for solving the problem is expressed as follows. Technical matters appearing in the expression are appended with numbers, symbols, etc. in parentheses. The numbers, symbols, and the like are technical matters constituting at least one embodiment or a plurality of embodiments of the present invention or a plurality of embodiments, in particular, the embodiments or examples. This corresponds to the reference numbers, reference symbols, and the like attached to the technical matters expressed in the drawings corresponding to. Such reference numbers and reference symbols clarify the correspondence and bridging between the technical matters described in the claims and the technical matters of the embodiments or examples. Such correspondence or bridging does not mean that the technical matters described in the claims are interpreted as being limited to the technical matters of the embodiments or examples.

  A solar cell (1) according to the present invention includes a transparent substrate (2), a solar cell element (3) provided on the transparent substrate (2) with a smaller width than the transparent substrate (2), and a transparent substrate. (2) A water repellent part provided on the water repellent part (4) having a water repellent effect and a protective material (5) covering the solar cell element (3) and the water repellent part (4). (4) is provided in at least a part between the end of the solar cell element (3) and the end of the protective material (5).

  According to the present invention, by providing the water repellent portion (4) between the end portion of the solar cell element (3) and the end portion of the protective material (5), the protective material (5) Even if water enters the inside and dew condensation occurs, the water is repellent and intermittent at the water repellent part (4). Since the water is intermittent, a closed electric circuit of "ground-frame-frame fitting water-condensed water-solar cell element-inverter-ground" is not formed, and a ground fault current is generated. Is prevented. Since the occurrence of a ground fault current is prevented, the promotion of corrosion of the solar cell element is suppressed.

  In the solar cell (1) according to the present invention, the transparent substrate (2) has a rectangular shape, the solar cell element (3) is provided in a rectangular shape, and the water repellent portion (4) is formed by the solar cell element (3). It is provided between the corner (31) and the end of the protective material (5).

  In the corner | angular part (31) of a solar cell element (3), it is a part where the sealing performance of the protective material (5) which coat | covers becomes weak, and the protective material (5) floats from a transparent substrate, and water is easy to infiltrate It is. By providing the water repellent part (4) between the corner part (31) and the end part of the protective material (5), water film formation between the solar cell element (3) and the outside is more effectively prevented. be able to.

In the solar cell (1) according to the present invention, the solar cell element (3) has a rectangular shape by arranging a plurality of strip-shaped solar cells (6) in parallel with the long sides being adjacent to each other, The plurality of solar cells (6) are connected in series, and the solar cell element (3) is provided in the vicinity of the side formed by the short side of each solar cell (6) and in parallel with the short side. A partial insulating groove (7),
The end insulating groove (7) insulates between the main power generation cell (61) which is the inner part of the solar battery cell (6) and the insulating cell (62) which is the outer part.

  In the solar cell (1) according to the present invention, the water repellent portion (4) is provided so as to cover the outer end portion (621) of the insulating cell (62A) in the outermost solar cell (6A).

  The outer end portion (621) of the insulating cell (62A) is a portion that is easily connected to the end portion of the protective material (5) by water. Therefore, by providing the water repellent portion (4) between the outer end portion (621) and the protective material (5) end portion, the water film formation between the solar cell element (3) and the outside is more effective. Can be prevented.

  In the solar cell (1) according to the present invention, the water repellent portion (4) is further provided so as to fill a portion where the outermost solar cell (6A) is divided by the end insulating groove (7). Yes.

  A high voltage is generated in the outermost solar cell (6A) when power is generated by light. Therefore, when a continuous water film is formed between the end (611) of the outer solar cell (6A) and the outside, a large amount of ground fault current may flow. According to the present invention, by providing the water repellent part (4) so as to cover the end part (611), generation of a ground fault current is more effectively prevented. Further, since the end insulating groove (7) is a gap, water easily enters and it is easy to form a continuous water film. By providing the water repellent part (4) in the end insulating groove (7), it is possible to prevent a continuous water film from being formed along the end insulating groove (7).

  In the solar cell (1) according to the present invention, the water repellent part (4) is further provided between the end of the solar cell element (3) and the end of the protective material (5). It is provided continuously so as to surround the outer periphery.

  In the solar cell (1) according to the present invention, the water repellent portion (4) is provided over the entire transparent substrate (2) exposed by removing the solar cell element (3) in the end insulating groove (7). ing.

  By providing the water repellent portion (4) over the entire end insulating groove (7), it is possible to prevent a continuous water film from being formed along the end insulating groove (7).

  In the solar cell (1) according to the present invention, the water repellent portion (4) is provided in contact with the end of the solar cell element (3).

  In the solar cell (1) according to the present invention, the water repellent part (4) is provided over 5 μm or more between the end of the solar cell element (3) and the end of the (5) protective material.

  When the width of the water repellent part (4) is 5 μm or less, the intermittent water film formed between the solar cell element (3) and the outside tends to be insufficient. On the other hand, since the water repellent part (4) is provided over 5 μm or more, the water film is more reliably interrupted.

  In the solar cell (1) according to the present invention, the water repellent part (4) has a contact angle with water of 90 degrees or more. When the contact angle of the water repellent part (4) is smaller than 90 degrees, the intermittent water film tends to be insufficient. On the other hand, when the contact angle with water is 90 degrees or more, the water film is surely intermittent.

The solar cell manufacturing method according to the present invention includes a solar cell element forming step (step S10) for forming a solar cell element (3) on the transparent substrate (2) in a narrower area than the transparent substrate (2),
After the solar cell element forming step (S0), a water repellent part forming step (step S20) for applying a water repellent agent on the transparent substrate (2) to form the water repellent part (4); and the solar cell element (3 And a step (Step S30) of providing a protective material (5) for covering the water repellent part (4), and in the water repellent part forming step (S10), the water repellent is the solar cell element (3). It is applied to at least a portion between the end portion and the planned position where the end portion of the protective material (5) is disposed.

The solar cell manufacturing method according to the present invention includes:
In the solar cell element forming step (S10), the solar cell element (3) is formed in a rectangular shape, and in the water repellent portion forming step (S20), the water repellent is the corner (31) of the solar cell element (3). And the protective material (5) are applied between the end positions where the end portions are arranged.

In the solar cell manufacturing method according to the present invention, the solar cell element forming step (S10) includes:
A step (Step S11) of forming a plurality of strip-shaped solar cells (6) on the entire surface of the transparent substrate (2) so that the long sides are adjacent to each other, and a short of each solar cell (6) A step (step S12) of forming an end insulating groove (7) provided in parallel with the short side and insulating the inside and the outside of each solar cell (6) in the vicinity of the side formed by the side (step S12); And removing the solar cell element (3) formed on the peripheral edge of the transparent substrate (2) (step S13).

  In the solar cell manufacturing method according to the present invention, in the water repellent portion forming step (S0), the water repellent is an insulating cell that is an outer cell of the end insulating groove (7) in the outermost solar cell (6A). It coat | covers so that the outer side edge part (621) of a cell (62A) may be covered.

  In the solar cell manufacturing method according to the present invention, in the water repellent portion forming step (S20), the water repellent material fills a portion where the outermost solar cell (6A) is divided by the end insulating groove (7). It is applied as follows.

  In the solar cell manufacturing method according to the present invention, in the water repellent portion forming step (S20), the water repellent agent is a transparent substrate (2) exposed by removing the solar cell element (6) in the end insulating groove (7). ) It is applied all over.

  In the solar cell manufacturing method according to the present invention, in the water repellent portion forming step (S20), the end portion of the solar cell element (3) and the end portion of the protective material (5) are scheduled to be disposed as the water repellent. It coat | covers so that it may surround and surround the outer peripheral part of a solar cell element (3) between positions.

  The solar cell manufacturing method according to the present invention includes a solar cell element forming step (step S40) for forming the solar cell element (6) on the entire surface of the transparent substrate (2), and a solar cell element forming step (S40). A step of applying a water repellent agent on the transparent substrate (2) to form a water repellent portion (4) (step S50), a water repellent portion (4) at the peripheral portion of the transparent substrate (2), and a solar cell element ( 6) (step S60) and a step (step S70) of providing a protective material (5) covering the solar cell element (3) and the water repellent part (4).

  After forming the water repellent part (4), the solar cell element (6) and the water repellent part (4) at the peripheral part of the transparent substrate (2) are removed, so that the transparent substrate at the peripheral part of the transparent substrate (2). (2) is bare. Since the transparent substrate (2) has good adhesion to the protective material (5), the protective material (5) can be formed with better adhesion.

In the solar cell manufacturing method according to the present invention, the solar cell element forming step (S40) includes:
A step (step S41) of forming a plurality of strip-shaped solar cells (6) on the transparent substrate (2) so that the long sides are adjacent to each other, and the short sides of each solar cell (6) Forming an end insulating groove (7) that is provided in parallel with the short side and insulates the inner side and the outer side of each solar cell (6) in the vicinity of the side formed by (Step S42); Have

  ADVANTAGE OF THE INVENTION According to this invention, the solar cell and the solar cell manufacturing method by which corrosion of the solar cell element by permeation of water were suppressed are provided.

  Furthermore, according to this invention, the solar cell and the solar cell manufacturing method which suppress corrosion of a solar cell element by suppressing generation | occurrence | production of a ground fault electric current are provided.

(First embodiment)
The solar cell 1 according to the present embodiment includes a transparent substrate 2, a solar cell element 3, a water repellent part 4, a protective material 5, a back sheet 8, and a current collecting copper foil. FIG. 2 is a diagram for explaining the arrangement of the solar cell element 3 and the water repellent portion 4 provided on the transparent substrate 2. Although the solar cell element 3 and the water repellent part 4 are actually covered with the protective material 5 and the back sheet 8, they are not visible, but are shown through for explanation. In addition, in this Embodiment, each structure in the case of using an amorphous silicon type solar cell for the solar cell element 3 is explained in full detail below.

  The transparent substrate 2 has a rectangular shape. Examples of the transparent substrate 2 include a soda float glass substrate (1.4 m × 1.1 m × plate thickness; 4 mm). The end face of the transparent substrate 2 is preferably subjected to corner chamfering or R chamfering to prevent breakage.

  The solar cell element 3 is formed on the transparent substrate 2. The solar cell element 3 has a rectangular shape that is narrower than the transparent substrate 2. That is, the solar cell element 3 does not exist at the peripheral edge of the transparent substrate 2.

  The solar cell element 3 includes a transparent electrode film 13 formed on the transparent substrate 2, a photoelectric conversion layer 14 formed on the transparent electrode film 13, a back electrode layer 15 formed on the photoelectric conversion layer 14, have. In the photoelectric conversion layer 14, an amorphous silicon p layer, an amorphous silicon i layer, and an amorphous silicon n layer film are laminated on the transparent electrode film 13 in this order. Further, a buffer layer may be provided between the amorphous silicon p layer and the amorphous silicon i layer film in order to improve interface characteristics. Examples of the back electrode layer 15 include an Ag film / Ti film. A GZO (Ga-doped ZnO film) may be provided between the amorphous n-layer film and the back electrode layer 15 for the purpose of reducing contact resistance and improving light reflection.

  The solar cell element 3 has a rectangular shape as a whole, but is divided into a plurality of strips that are long in the X direction in FIG. Adjacent solar cells 6 are electrically connected in series. That is, the solar cell element 3 has a rectangular shape in which a plurality of strip-shaped solar cells 6 are arranged in parallel with long sides adjacent to each other. The solar cell element 3 has an end insulating groove 7 provided in parallel with the short side in the vicinity of the side formed by the short sides of the plurality of solar cells 6 (the side parallel to the Y direction in FIG. 2). is doing. In the end insulating groove 7, the solar cell element 3 is removed. Hereinafter, for convenience of explanation, the solar battery cell 6 outside the end insulating groove 7 is referred to as an insulation cell 62, and the solar battery element inside is referred to as a main power generation cell 61. In each solar cell 6, the insulating cell 62 and the main power generation cell 61 are insulated from each other by the end insulating groove 7.

  The water repellent part 4 is provided on the transparent substrate 2. In FIG. 2, the water repellent portion 4 is continuously provided so as to surround the outer periphery of the solar cell element 3. Although not shown in FIG. 2, it is also provided to fill the end insulating groove 7.

  The water repellent part 4 has a water repellent effect. Due to the water repellent effect of the water repellent part 4, it is possible to prevent the formation of a continuous film of water at the interface between the transparent substrate 2 and the protective material 5. Since the adhesion between the water repellent part 4 and the protective material 5 is generally not high, it is desirable to keep the width of the water repellent part 4 to the minimum necessary. Since water is water repellent and intermittent on the water repellent portion 4, it is possible to prevent a ground fault current from flowing from the solar cell element 3 through the water.

  The width of the water repellent part 4 is preferably 5 μm or more. If the width of the water repellent part 4 is 5 μm or less, a sufficient water repellent effect may not be obtained in order to intermittently form the water film.

As the material of the water repellent part 4, “Novec EGC; trade name, manufactured by Sumitomo 3M”, silicone wax, silicone polymer, organic silane coupling agent exemplified by CH ₃ Si (OCH ₃ ) ₃ , CH An organic titanium coupling agent exemplified by ₁₇ H ₃₅ COO) ₃ Ti (OC ₃ H ₇ ) and the like can be mentioned.

  The water repellent part 4 preferably has a contact angle with water of 30 ° or more, more preferably 90 ° or more. If the contact angle of the water repellent part 4 is small, water may not be sufficiently repelled.

The water repellent part 4 preferably has a volume resistivity of 100 × 10 ⁶ (Ωm) or more. When the volume resistivity is smaller than 100 × 10 ⁶ (Ωm), there is a concern that a ground fault current flows through the water repellent part 4 itself.

  When the protective material 5 covering the water repellent part 4 is formed, since the adhesion treatment may be performed at a temperature of about 150 ° C., the water repellent part 4 is formed of a material that does not thermally decompose at 150 ° C. or less. Preferably it is.

  The thickness of the water repellent portion 4 is not particularly limited, but is preferably thicker than the solar cell element 3. If it is thicker than the solar cell element 3, the water film formed at the end of the solar cell element 3 can be more intermittently interrupted. However, since the water electrically connecting the solar cell element 3 and the outside is a water film formed mainly at the interface between the transparent substrate 2 and the protective material 5, the water repellent portion 4 is in direct contact with the transparent substrate 2. Need to be provided.

  In the present embodiment, the water repellent part 4 is provided in a continuous part so as to surround the outer periphery of the solar cell element 3 and an end insulating groove 7 part. However, the water repellent part 4 is not necessarily provided in all of these parts. Although the protective material 5 is provided on the water repellent part 4, the adhesiveness between the water repellent part 4 and the protective material 5 may not always be good. In such a case, when the water repellent part 4 is provided in a large area, the protective material 5 covering the water repellent part 4 may be peeled off. For example, if the water-repellent part 4 is provided on the entire peripheral edge where the solar cell element 3 is not provided, the occurrence of a ground fault current can be reliably suppressed, but the adhesiveness with the protective material 5 may not be sufficiently obtained. is there. Therefore, it is desirable that the position of the water repellent part 4 is considered so that the adhesiveness with the protective material 5 can be secured and the occurrence of a ground fault current can be effectively suppressed. In addition, when the water repellent part 4 is provided in the position described below, generation of a ground fault current can be effectively suppressed.

  The water repellent part 4 is particularly preferably provided outside the corner part 31 of the solar cell element 3. FIG. 3A is an enlarged plan view of a corner portion of the solar cell. The solar cell element 3 has a rectangular shape as a whole, and a water repellent portion 41 is provided outside the corner portion 31 of the solar cell element 3. In the corner portion 31, the sealing property of the protective material 5 is easily affected by heat shrinkage and tends to be weakened. Therefore, in the vicinity of the corner portion 31, a gap is easily generated at the interface between the protective material 5 and the transparent substrate 2 as compared with other positions. In this gap, a film in which water that has entered from the end of the protective material 5 or water that has condensed is formed may be formed, and the corner 31 of the solar cell element 3 may be electrically connected to the outside. By providing the water repellent portion 4 outside the corner portion 31 of the solar cell element 3, it is possible to prevent continuation of water in the corner portion 31 having a weak sealing property. When the solar cell element 3 has a plurality of strip-shaped solar cells and is divided by the end insulating grooves 7 as in the present embodiment, the corner portion 31 is the outermost solar cell. This is the outer end 621 of the insulating cell 62A of the cell 61A. That is, as shown in FIG. 3A, the water repellent part 41 is provided outside the outer end 621.

  It is preferable that the water repellent part 4 is further provided so as to fill the position where the end insulating groove 7 divides the outermost solar cell 6A. In this Embodiment, as FIG. 3A shows, the water-repellent part 42 is provided in the part into which the edge part insulating groove 7 divides | segments the photovoltaic cell 6A. Since the end insulating groove 7 is a groove, it is a portion where water is likely to condense and a water film continuous to the outside is easily formed. By providing the water repellent part 42, even if water accumulates in the end insulating groove 7, it is possible to prevent the solar cell element 3 from being electrically connected to the outside. The outermost solar battery cell 6A is a cell that becomes a high voltage during power generation. Therefore, when the main power generation cell 61A of the solar battery cell 6A is electrically connected to the outside through the water film, a large amount of ground fault current may flow. By providing the water repellent portion 42, a short circuit between the main power generation cell 61A of the solar battery cell 6A and the outside is prevented.

  It is more preferable that the water repellent part 4 is provided so as to surround the outer peripheral part of the solar cell element 3. Referring to FIG. 3A, a water repellent portion 43 is provided so as to surround the outer periphery of the solar cell element 3 (partly overlaps the water repellent portions 41 and 42).

  The water repellent part 4 is preferably provided so as to fill the entire end insulating groove 7. Since the solar cell element 3 is removed in the end insulating groove 7, a step with the surrounding solar cell element 3 is generated. Therefore, water tends to accumulate in the end insulating groove 7, and the solar cell element 3 and the outside are likely to cause electrical connection. By providing the water repellent portion 44 so as to fill the entire end insulating groove 7, the water film formed in the end insulating groove 7 can be intermittent.

  3B is a cross-sectional view taken along AA 'in FIG. 3A. The water repellent part 4 is preferably provided so as to be in contact with the end of the solar cell element 3. Since the water repellent portion 4 is in contact with the end portion of the solar cell element 3, the water film can be prevented from being intermittently interrupted.

  The protective material 5 is rectangular. The protective material 5 is provided so as to cover the solar cell element 3 and the water repellent part 4. As shown in FIG. 2, the end portion of the protective material 5 is disposed on the surface of the transparent substrate 2 on which the solar cell element 3 is formed. Examples of the protective material 5 include insulating resins such as ethylene-vinyl acetate copolymer (EVA). In addition to preventing water from entering the solar cell, the protective material 5 is formed for the purpose of adhering the back sheet 8 and the solar cell element 3 and preventing damage to the solar cell due to physical damage.

  Refer to FIG. 3B. The back sheet 8 is formed on the protective material 5. The back sheet 8 is provided in order to further improve waterproofness and moisture resistance. Examples of the back sheet 8 include those having a three-layer structure of PET sheet / AL foil / PET sheet.

  FIG. 4 is a cross-sectional view showing a state where the solar cell according to the present embodiment is fixed and installed on a frame. The solar cell module having the configuration as described above is fitted and fixed to the frame 13 having a fitting portion corresponding to the shape of the transparent substrate 2. Moreover, the copper foil 9 for current collecting plates is electrically connected to solar cell 6A, 6B located in both ends among the some photovoltaic cell 6. FIG. The current collecting copper foil 9 is covered with an insulating sheet (not shown) for insulation from each member. A water repellent portion 4 is provided between the end portion of the solar cell element 3 and the end portion of the protective material 5. The other end of the current collecting copper foil 9 is taken out through the openings provided in the protective material 5 and the back sheet 8. The collecting copper foil 9 taken out to the outside is electrically connected to an output cable 10 provided in the terminal box 11. The output cable 10 is connected to the inverter 12, and the electric power generated by the solar cell element 6 is converted by the inverter 12 and used. That is, the water repellent part 4 is added to the conventional example shown in FIG. 1B. Therefore, the water that has entered the protective material 5 is condensed at the interface between the protective material 5 and the transparent substrate 2, and the water is collected in the fitting portion of the frame and the end of the solar cell module is submerged. However, due to the water repellent effect of the water repellent portion 4, a closed circuit of “ground-frame-frame fitting portion water-condensed water-solar cell element-inverter-ground” is not formed. Therefore, a ground fault current from the solar cell element 3 to the ground does not occur, and corrosion of the solar cell element 3 is suppressed.

(Production method)
Then, the manufacturing method of the solar cell 1 which concerns on this Embodiment is demonstrated. FIG. 5 shows a flowchart of the solar cell manufacturing method according to the present embodiment. The method for manufacturing solar cell 1 according to the present embodiment includes the step of forming a solar cell element (step S10), the step of forming a water repellent portion (step S20), and the step of forming a protective material (step S30). I have. Details of each step will be described in detail below.

Step S10: Formation of Solar Cell Element First, in step 10, the solar cell element 3 is formed on the transparent substrate 2. The step (S10) of forming the solar cell element includes a step of forming a plurality of strip-shaped solar cells (step S11), a step of forming end insulating grooves (step S12), and the solar cell element 3 in the outer peripheral portion. Is removed (step S13). The operation at each step will be described below. 7 and 8 are schematic views for explaining an embodiment of a method for manufacturing a solar cell panel.

Step S11: Form a plurality of strip-shaped solar cells (1) FIG. 7 (a)
A soda float glass substrate (1.4 m × 1.1 m × plate thickness: 4 mm) is used as the transparent substrate 2. It is desirable that the end face of the substrate is corner chamfered or rounded to prevent breakage.
(2) FIG. 7 (b)
On one surface of the transparent substrate 2, a transparent electrode film having a tin oxide film (SnO ₂ ) as a main component as a transparent conductive layer 13 is formed at a temperature of about 500 to 800 nm in a thermal CVD apparatus at about 500 ° C. At this time, a texture with appropriate irregularities is formed on the surface of the transparent electrode film. As the transparent conductive layer 13, in addition to the transparent electrode film, an alkali barrier film (not shown) may be formed between the transparent substrate 2 and the transparent electrode film. As the alkali barrier film, a silicon oxide film (SiO ₂ ) is formed at a temperature of about 500 ° C. in a thermal CVD apparatus with a thickness of 50 to 150 nm.
(3) FIG. 7 (c)
Thereafter, the transparent substrate 2 is placed on an XY table, and the first harmonic (1064 nm) of the laser diode-pumped YAG laser is incident from the film surface side of the transparent electrode film as indicated by the arrow in the figure. Pulse oscillation: The laser power is adjusted so that the processing speed is appropriate at 5 to 20 kHz, and the groove 16 is formed in the direction perpendicular to the series connection direction of the solar cells (X direction in the figure). Laser etching is performed in a strip shape having a width of about 6 to 10 nm so as to extend.
(4) FIG. 7 (d)
Using a plasma CVD apparatus, a p-layer film / i-layer film / n-layer film made of an amorphous silicon thin film as the photoelectric conversion layer 14 is sequentially formed at a reduced pressure atmosphere of 30 to 150 Pa and about 200 ° C. The photoelectric conversion layer 14 is formed on the transparent copper electrode layer 13 using SiH ₄ gas and H ₂ gas as main raw materials. The p-layer, i-layer, and n-layer are stacked in this order from the sunlight incident side. In this embodiment, the photoelectric conversion layer 14 is a p-layer: B-doped amorphous SiC and a film thickness of 10 to 30 nm, an i-layer: amorphous Si and a film thickness of 250-350 nm, and an n-layer: p-doped microcrystal. Si is the main film thickness. A buffer layer may be provided between the p layer film and the i layer film in order to improve the interface characteristics.
(5) FIG. 7 (e)
The transparent substrate 2 is placed on the XY table, and the second harmonic (532 nm) of the laser diode pumped YAG laser is incident from the film surface side of the photoelectric conversion layer 14 as indicated by the arrow in the figure. Pulse oscillation: Laser power is adjusted so that the processing speed is appropriate at 10 to 20 kHz, and a laser is formed so that a groove 17 from which the photoelectric conversion layer 14 is removed is formed on the lateral side of the groove 16 about 100 to 150 μm. Etch.
(6) FIG. 8 (a)
As the back electrode layer 15, an Ag film / Ti film is sequentially formed by a sputtering apparatus at a reduced pressure atmosphere at about 150 ° C. In this embodiment, the back electrode layer 15 is formed by stacking an Ag film: 200 to 500 nm and a Ti film having a high anticorrosion effect: 10 to 20 nm in this order as a protective film. For the purpose of reducing contact resistance between the n-layer and the back electrode layer 4 and improving light reflection, a GZO (Ga-doped ZnO film) film thickness between the photoelectric conversion layer 14 and the back electrode layer 15 is 50 to 100 nm, a sputtering apparatus. May be provided by forming a film.
(7) FIG. 8 (b)
The transparent substrate 2 is placed on an XY table, and the second harmonic (532 nm) of the laser diode-pumped YAG laser is incident from the transparent substrate 2 side as indicated by the arrow in the figure, so that the laser light is photoelectrically generated. The back electrode layer 15 is exploded and removed using the high gas vapor pressure that is absorbed by the conversion layer 14 and generated at this time. Pulse oscillation is set to 1 to 10 kHz, laser power is adjusted so that the processing speed is appropriate, and laser etching is performed so that the lateral side of the groove 17 about 250 μm to 400 μm extends in the X direction. Thereby, the separation groove 18 extending in the X direction and having the photoelectric conversion layer 14 and the back electrode layer 15 removed is formed.

  Through the above steps, a solar cell element 3 is formed in which a plurality of strip-shaped solar cells 6 having long sides in the X direction are connected in series in the Y direction.

Step S12: Forming End Insulating Groove 7 FIG. 9 is a view of the transparent substrate 2 as seen from the film surface side. In the film edge part around the edge of the transparent substrate 2, the influence that the serial connection part by laser etching tends to be short-circuited is removed. The transparent substrate 2 is placed on an XY table, and the second harmonic (532 nm) of the laser diode-pumped YAG laser is incident from the transparent substrate 2 side, so that the laser light is transmitted to the transparent conductive layer 2 and the photoelectric conversion layer 14. The back electrode layer 15 is exploded and removed using the high gas vapor pressure generated at this time. That is, the end insulating groove 7 from which the transparent conductive layer 2, the photoelectric conversion layer 14, and the back electrode layer 15 are removed is formed. Pulse oscillation: 1-10 kHz The laser power is adjusted so as to be suitable for the processing speed, and the end insulating groove 7 parallel to the X direction is placed at a position 5 to 10 mm from the X direction end of the transparent substrate 2. Laser etching to form. At this time, no insulating groove is provided in the Y direction. The end insulating groove 17 terminates the etching at a position of 5 to 10 mm from the end of the transparent substrate 2. The etching may be terminated by stopping the laser beam, but can be dealt with simply by installing a metal masking plate in the non-laser etching region of the transparent substrate 2. By terminating the etching at a position of 5 to 10 mm from the end of the transparent substrate 2, an effective effect is exhibited in suppressing the intrusion of external moisture from the end of the transparent substrate 2 to the inside.

Step S13: Removal of the outer peripheral solar cell element 3 In order to secure a healthy adhesion surface with the back sheet through EVA or the like in the post-process, the outer peripheral portion of the transparent substrate 2 (peripheral region 19 in FIG. 9) The solar cell element 3 is removed because it has a step and is easy to peel off. The back electrode layer 15 / photoelectric conversion layer 14 / transparent conductive layer 13 is polished and removed 5 to 15 mm from the end of the transparent substrate 2 and closer to the end of the transparent substrate 2 than the end insulating groove 17 described above. In addition, polishing waste and abrasive grains are removed by cleaning the transparent substrate 2.

  The process of the step (S10) for forming the solar cell element is completed by the processes of steps S11 to S13.

Step S20: Formation of the water repellent portion Subsequently, a water repellent material is applied to a predetermined position on the transparent substrate 2 on which the solar cell element 3 is formed. The position where the water repellent material is applied is the position where the water repellent portion 4 described above is provided. As the water repellent material, “Novec EGC; trade name, manufactured by Sumitomo 3M”, silicone wax, silicone polymer, organic silane coupling agent exemplified by CH ₃ Si (OCH ₃ ) ₃ , CH ₁₇ H ₃₅ An organic titanium coupling agent exemplified by COO) ₃ Ti (OC ₃ H ₇ ) can be used. The water repellent part 4 is formed by applying the water repellent material and then drying it. As a method of applying the water repellent material to a predetermined position (selective position) on the transparent substrate 2, there is a method of injecting the application material to a predetermined position from a thin tube such as an injection needle held by a robot. . The applied water repellent material permeates the desired power generation film edge by capillary action to form a film.

Step S30: Forming the protective material Subsequently, in the portion where the terminal box is attached, an opening through window is provided in the back sheet and the current collector plate is taken out. A plurality of layers of insulating materials are installed in the opening through window portion to suppress intrusion of moisture and the like from the outside. It collects using the copper foil from the photovoltaic cell 6 of the one end and the photovoltaic cell 6 of the other end part arranged in series, and processes so that electric power can be taken out from the back side of a photovoltaic panel. The copper foil is covered with an insulating sheet wider than the width of the copper foil in order to prevent a short circuit with each part. After the current collecting copper foil or the like is disposed at a predetermined position, an EVA protective material sheet is disposed so as to cover the solar cell element 3 and the water repellent portion 4 and not to protrude from the transparent substrate 2. A back sheet having a high waterproofing effect is disposed on the EVA. In the present embodiment, the back sheet has a three-layer structure of PET sheet / AL foil / PET sheet having a high waterproof and moisture proof effect. The EVA sheet is crosslinked and brought into close contact with the one arranged at a predetermined position up to the back sheet while being pressed at about 150 to 160 ° C. in a state where the inside is deaerated in a reduced pressure atmosphere by a laminator. Thereby, the solar cell module 24 in which the protective material 5 and the back sheet are formed is created.

  Please refer to FIG. As shown in FIG. 10A, the terminal box is attached to the non-light-receiving surface side (upper side in the drawing) of the solar cell module 24 with an adhesive. 10B, the copper foil and the output cable of the terminal box are connected by solder or the like, and the inside of the terminal box is filled with a sealing material (potting agent) and sealed. Further, the frame is attached and the solar cell panel 50 is completed. The output cable is connected to an inverter (not shown).

As shown in FIG. 10C, light is irradiated from the light receiving surface side of the solar cell panel 50, and a power generation inspection and a predetermined performance test are performed. The power generation inspection is performed using a solar simulator of AM1.5 and solar radiation standard sunlight (1000 W / m ² ).

  As shown in FIG. 10D, a predetermined performance test is performed before and after the power generation inspection.

  When the solar cell panel 50 manufactured by the solar cell manufacturing method described above was subjected to an insulation test, a withstand voltage test, and a high-temperature and high-humidity test, the performance changed even when compared with a solar cell without the water-repellent part 4. It was confirmed that there was no. Each test method is described below.

(1) Insulation inspection:
A DC: 1000V load is applied between the output terminal of the laminated solar cell panel and a conductive portion such as a substrate end face or a back sheet, and it is confirmed that the resistance value ≧ 100 MΩ.
(2) Withstand voltage inspection:
DC: 3800 V (or 2200 V) is applied for 1 minute between the output terminal of the laminated solar cell panel and the conductive portion such as the end face of the substrate or the back sheet to confirm that there is no dielectric breakdown.
(3) High temperature and high humidity test:
The final confirmation that the structure and manufacturing conditions are appropriate due to the change in the manufacturing method was performed after simulating outdoor harsh conditions and stabilizing the performance in advance by light exposure for 20 hours in accordance with JISC8938. , High temperature and high humidity conditions: temperature 85 ° C., humidity: 85%, it is confirmed that the performance does not change in the evaluation time 1000 hours. (Verify that there is no change in appearance and that 95% or more of the initial performance value is secured and that there is no change in performance.)

(Action / Effect)
According to the present embodiment, by providing the water repellent part 4, even when the water that has entered the EVA sheet is condensed at the interface between the EVA sheet and the transparent substrate 2, the water repellent part 4 is water repellent. Therefore, the film is not continuous with the outside but is intermittent. Therefore, a closed circuit of “ground-inverter-solar cell element 3-water condensed at the interface-external (water accumulated in the frame fitting portion) -frame-ground” is not formed. Therefore, even if a voltage difference is generated between the ground and the solar cell element 3 due to solar power generation, no ground fault current flows from the solar cell element 3 to the outside (ground). Is suppressed.

(Second Embodiment)
A second embodiment of the present invention will be described. The solar cell according to the present embodiment is devised with respect to the solar cell according to the first embodiment in terms of the position of the water repellent part 4 and the solar cell manufacturing method. A description of the same configuration and manufacturing method as in the first embodiment will be omitted.

(Constitution)
FIG. 11 is a view of solar cell 1 according to the present embodiment as viewed from the non-light-receiving surface side. As in the first embodiment, the solar cell element is formed by connecting a plurality of strip-shaped solar cells 6 in series in the Y direction on the transparent substrate 2. Further, an end insulating groove 7 extending in the Y direction is formed in the vicinity of the X direction end of the solar cell element 6. Further, the protective material 5 is disposed on the transparent substrate 2 so as to cover the solar cell element 6. The water repellent part 4 is provided so as to fill the entire end insulating groove 7.

(Production method)
FIG. 6 is a flowchart showing a method for manufacturing a solar cell according to the present embodiment. The solar cell manufacturing method according to the present embodiment includes a step of forming a solar cell element on the entire surface (step S40), a water repellent portion forming step (step S50), and a step of removing the peripheral solar cell element (step S60). And a step of forming a protective material (step S70). The processing of each step will be described in detail below.

Step S40: Forming a solar cell element on the entire surface First, the solar cell element 3 is formed on the entire surface of one side (non-light receiving surface) of the transparent substrate 2. A solar cell element is formed. The formation of the solar cell element includes a step of forming a plurality of strip-shaped solar cells (step S41) and a step of forming the end insulating groove 7 (step S42).

Step S41: Formation of Solar Cell As in step S11 in the first embodiment, the solar cell element 3 is formed on the entire surface of the transparent substrate 2. In the solar cell element 3, a plurality of strip-shaped solar cells 6 having long sides in the X direction are connected in series in the Y direction.

Step S42: Formation of End Insulating Groove Similar to step S12 in the first embodiment, the end insulating groove 7 parallel to the short side direction of the strip-shaped solar battery cell is formed.

Step S50: Formation of Water Repellent Portion Subsequently, a water repellent material is applied to the entire surface of the substrate and dried. The applied water repellent material mainly enters the end insulating groove 7, and the water repellent part 4 is formed so as to fill the entire end insulating groove 7.

Step S60: Removal of peripheral edge Subsequently, the peripheral edge of the transparent substrate 2 is removed. The method for removing the peripheral edge is the same as step S13 in the first embodiment.

Step S70: Formation of Protective Material Subsequently, the solar cell module 24 in which the protective material 5 and the back sheet are disposed is formed by the same method as in step S30 and subsequent steps in the first embodiment. Furthermore, a terminal box, a frame, etc. are attached, and the solar cell panel 50 is created.

  When the solar cell panel 50 manufactured by the solar cell manufacturing method described above was subjected to an insulation test, a withstand voltage test, and a high-temperature and high-humidity test, the performance changed even when compared with a solar cell without the water-repellent part 4. It was confirmed that there was no. Each test method is the same method as in the first embodiment.

(Action / Effect)
According to the present embodiment, in the step of applying the water repellent material, it may be applied to the entire surface of the substrate, and there is no need to select the position. Therefore, the step of selecting the application position of the water repellent material is omitted. Furthermore, the water condensed in the end insulating groove 7 is prevented from forming a continuous film. Therefore, it is possible to prevent the solar cell element 6 from being electrically connected to the outside, and to suppress the occurrence of a ground fault current.

  In the first and second embodiments, the case where an amorphous silicon type solar cell is used as the solar cell element 3 has been described. However, in order to achieve a high voltage structure during power generation as in the case of an amorphous silicon type solar cell. Thin-film solar cells such as microcrystalline silicon solar cells in which a ground fault current is easily generated, and multi-junction solar cells using a plurality of laminated amorphous silicon semiconductor layers and microcrystalline silicon semiconductor layers as solar cell elements 3 This is particularly useful when applied to batteries. Also, when applied to a crystalline solar cell in which the solar cell element 3 is formed using a single crystal silicon substrate or a polycrystalline silicon substrate, it is useful, if not as thin film solar cells. It will be obvious to the contractor.

It is a figure explaining the generation | occurrence | production mechanism of a ground fault electric current. It is a figure explaining the generation | occurrence | production mechanism of a ground fault electric current. It is a top view of the solar cell module which concerns on 1st Embodiment. It is an enlarged view of the corner | angular part in FIG. It is sectional drawing by the AA 'cross section of FIG. 3A. It is the schematic which shows the state in which the solar cell which concerns on 1st Embodiment was installed. It is a flowchart of the solar cell manufacturing method which concerns on 1st Embodiment. It is a flowchart of the solar cell manufacturing method which concerns on 2nd Embodiment. It is a figure for demonstrating the manufacturing method of a solar cell element. It is a figure for demonstrating the manufacturing method of a solar cell element. It is a figure for demonstrating the peripheral area | region 19. FIG. It is a figure for demonstrating the manufacturing method of a solar cell panel. It is a top view of the solar cell module which concerns on 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Solar cell 2 Transparent substrate 3 Solar cell element 31 Corner | angular part of solar cell element 4 Water repellent part 5 Protective material 6 Solar cell 61 Main power generation cell 611 Main power generation cell edge 62 Insulation cell 621 Outer end 622 Insulation cell inner end Part 7 End insulating groove 8 Back sheet 9 Current collecting copper foil 10 Output cable 11 Terminal box 12 Inverter 13 Transparent electrode film 14 Photoelectric conversion layer 15 Back electrode layer 16 Groove 17 Groove 18 Separation groove 19 Peripheral area 24 Solar cell module 50 Solar panel

Claims (19)

A transparent substrate;
On the transparent substrate, a solar cell element provided in a narrower area than the transparent substrate,
A water repellent portion provided on the transparent substrate and having a water repellent effect;
A protective material covering the solar cell element and the water repellent part;
Comprising
The water repellent portion is a solar cell provided at least at a part between an end portion of the solar cell element and an end portion of the protective material. A solar cell according to claim 1,
The transparent substrate has a rectangular shape,
The solar cell element is provided in a rectangular shape,
The water repellent portion is a solar cell provided between a corner portion of the solar cell element and an end portion of the protective material. A solar cell according to claim 2,
The solar cell element is formed in a rectangular shape as a whole by arranging a plurality of strip-shaped solar cells adjacent to each other in parallel,
The plurality of solar cells are connected in series,
The solar cell element has an end insulating groove provided in parallel with the short side in the vicinity of the side formed by the short side of each solar cell,
The end insulating groove is a solar cell that insulates between a main power generation cell that is an inner portion of each solar cell and an insulating cell that is an outer portion. A solar cell according to claim 3,
The water repellent part is a solar battery provided so as to cover an outer end part of the insulating cell in the outermost solar battery cell. A solar cell according to claim 3 or 4, wherein
The water-repellent part is a solar battery provided such that the outermost solar battery cell fills a portion divided by the end insulating groove. A solar cell according to any one of claims 3 to 5,
The water repellent portion is a solar cell that is continuously provided so as to surround the outer peripheral portion of the solar cell element between the end portion of the solar cell element and the end portion of the protective material. A solar cell according to any one of claims 3 to 6,
The water repellent portion is a solar cell provided over the entire transparent substrate exposed by removing the solar cell element in the end insulating groove. A solar cell according to any one of claims 1 to 7,
The water repellent portion is a solar cell provided in contact with an end portion of the solar cell element. A solar cell according to any one of claims 1 to 8,
The water repellent portion is a solar cell provided over 5 μm or more between an end portion of the solar cell element and an end portion of the protective material. A solar cell according to any one of claims 1 to 9,
The water repellent part is a solar cell having a contact angle with water of 90 degrees or more. A solar cell element forming step for forming a solar cell element on a transparent substrate in a narrower area than the transparent substrate;
A water-repellent part forming step of forming a water-repellent part by applying a water-repellent agent on the transparent substrate after the solar cell element forming step;
Providing a protective material covering the solar cell element and the water repellent part;
Comprising
The said water-repellent part formation step WHEREIN: The said water-repellent agent is a solar cell manufacturing method apply | coated to at least one part between the edge part of the said solar cell element, and the plan position where the edge part of the said protective material is arrange | positioned. It is a solar cell manufacturing method described in Claim 11,
In the solar cell element forming step, the solar cell element is formed in a rectangular shape,
In the water repellent portion forming step, the water repellent is applied between a corner portion of the solar cell element and a planned position where an end portion of the protective material is disposed. A method for manufacturing a solar cell according to claim 11 or 12,
The solar cell element forming step includes:
Forming a plurality of strip-shaped solar cells on the entire surface of the transparent substrate so that the long sides are adjacent to each other in parallel with each other;
Forming an end insulating groove that is provided in parallel with the short side and insulates the inner side and the outer side of each solar cell in the vicinity of the side formed by the short side of each solar cell;
Removing the solar cell element formed on the peripheral edge of the transparent substrate;
A method of manufacturing a solar cell. A method for manufacturing a solar cell according to claim 13,
In the water repellent portion forming step, the water repellent agent is applied so as to cover an outer end portion of an insulating cell which is a cell outside the end portion insulating groove in the outermost solar cell element. . The solar cell manufacturing method according to claim 13 or 14,
In the water repellent portion forming step, the water repellent is applied so that the outermost solar cell fills a portion divided by the end insulating groove. A method for manufacturing a solar cell according to any one of claims 13 to 15,
In the water repellent portion forming step, the water repellent is applied over the entire transparent substrate exposed by removing the solar cell element in the end insulating groove. A solar cell manufacturing method according to any one of claims 11 to 16, wherein
In the water repellent portion forming step, the water repellent agent surrounds the outer peripheral portion of the solar cell element between the end portion of the solar cell element and the position where the end portion of the protective material is to be disposed. A solar cell manufacturing method applied continuously. A solar cell element forming step for forming the solar cell element on the entire surface of the transparent substrate;
After the solar cell element forming step, forming a water repellent part by applying a water repellent on the transparent substrate;
Removing the water repellent part and the solar cell element at the peripheral edge of the transparent substrate;
Providing a protective material covering the solar cell element and the water repellent part;
A solar cell manufacturing method comprising: A solar cell manufacturing method according to claim 18,
The solar cell element forming step includes:
On the transparent substrate, a plurality of strip-shaped solar cells are formed in parallel so that the long sides are adjacent to each other;
Forming an end insulating groove that is provided in parallel with the short side and insulates the inner side and the outer side of each solar cell in the vicinity of the side formed by the short side of each solar cell;
A method of manufacturing a solar cell.

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