JP2013089666A - Photoelectric conversion module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly reliable photoelectric conversion module in which infiltration of moisture into a photoelectric conversion part is reduced.SOLUTION: A photoelectric conversion module 100 includes: a substrate 1; a photoelectric converter L provided on the substrate 1; a wiring conductor 9 which is positioned at a portion separated from the photoelectric converter L on the substrate 1 and is for extracting electric output generated by the photoelectric converter L to the outside; a sealing material 13 for sealing the photoelectric converter L; and a low moisture-permeable member W which is interposed between the photoelectric converter L and the wiring conductor 9 and has moisture permeability lower than that of the sealing material 13.

Description

  The present invention relates to a photoelectric conversion module.

  In recent years, photovoltaic power generation that converts light energy into electric energy has attracted attention as energy problems and environmental problems become more serious.

  In the photoelectric conversion module used for this photovoltaic power generation, electricity obtained from the photoelectric conversion unit provided in the photoelectric conversion module is taken out by a wiring conductor such as a lead wire. This wiring conductor is led out inside a terminal box disposed on the non-light-receiving surface of the photoelectric conversion module (see, for example, Patent Document 1). In such a photoelectric conversion module, the electrical output generated by the photoelectric conversion module is led to an external circuit or the like via the terminal box.

JP 2006-216608 A

  When the photoelectric conversion module is installed outdoors for a long period of time, moisture may enter the inside of the photoelectric conversion module from the outside, altering the members such as the photoelectric conversion unit, and the output of the photoelectric conversion module may be reduced. .

  The present invention has been made in view of such problems, and an object of the present invention is to provide a highly reliable photoelectric conversion module that reduces moisture permeation into the photoelectric conversion unit.

  A photoelectric conversion module according to an embodiment of the present invention occurs in the photoelectric conversion body that is located on a substrate, a photoelectric conversion body provided on the substrate, and a part of the substrate that is away from the photoelectric conversion body. A wiring conductor for taking out the electrical output, a sealing material for sealing the photoelectric conversion body, and a moisture permeability lower than the sealing material interposed between the photoelectric conversion body and the wiring conductor. A low moisture-permeable member.

  According to the photoelectric conversion module according to the embodiment of the present invention, the reliability of the photoelectric conversion module is improved.

It is a principal part expansion perspective view which shows an example of embodiment of a photoelectric conversion module. It is sectional drawing of the photoelectric conversion module of FIG. It is a perspective view which shows the whole photoelectric conversion module of FIG. It is a perspective view which shows the back surface of the photoelectric conversion module of FIG. It is a principal part expanded sectional view which shows the other example of embodiment of a photoelectric conversion module.

  Hereinafter, a photoelectric conversion module according to an embodiment of the present invention will be described in detail with reference to the drawings.

<Configuration of photoelectric conversion module>
FIG. 1 is an essential part enlarged perspective view showing an example of a photoelectric conversion module according to one embodiment of the present invention, and FIG. 2 is an XZ sectional view thereof. 3 is a perspective view showing the entire photoelectric conversion module of FIG. 1, and FIG. 4 is a perspective view seen from the back side. 1, 3, and 4, the sealing material and the cover member are omitted so that the state of the photoelectric conversion unit can be seen well. The photoelectric conversion module 100 includes a photoelectric conversion unit 11 and a pair of lead-out wiring units 12 on a substrate 1.

  The photoelectric conversion unit 11 includes a plurality of photoelectric conversion cells 10 arranged along the X-axis direction. The photoelectric conversion cell 10 includes a lower electrode layer 2, a first semiconductor layer 3 having a first conductivity type, a second semiconductor layer 4 having a second conductivity type different from the first conductivity type, The upper electrode layer 5 is laminated in order. For example, if the first conductivity type is p-type, the second conductivity type is n-type, and vice versa. In FIG. 2, the first semiconductor layer 3a and the second semiconductor layer 4a are provided from the lower electrode layer 2a to the lower electrode layer 2b. Similarly, the first semiconductor layer 3b and the second semiconductor layer 4b are provided from the lower electrode layer 2b to the lower electrode layer 2c, and the first semiconductor layer 3c and the second semiconductor layer 4c are It is provided from the lower electrode layer 2c to the lower electrode layer 2d. The first semiconductor layers 3a to 3c and the second semiconductor layers 4a to 4c laminated on the first semiconductor layers 3a to 3c constitute the photoelectric converters La to Lc, and the photoelectric converters La to Lc are irradiated with light. As a result, carriers are generated and carrier separation is performed well. Carriers of the first conductivity type generated by the photoelectric conversion move from the first semiconductor layer 3 to the lower electrode layer 2. On the other hand, carriers of the second conductivity type generated by photoelectric conversion move from the second semiconductor layer 3 to the upper electrode layer 4 and move to the adjacent lower electrode layer 2 via the connection conductor 7. With such a configuration, adjacent photoelectric conversion cells 10 are connected in series.

  The lead-out wiring part 12 is for taking out the carrier generated in the photoelectric conversion part 11 to the outside of the photoelectric conversion module 100. That is, the electrical output generated by the photoelectric conversion unit 11 is drawn out to the outside by the lead-out wiring unit 12. The lead wiring portion 12 has one end of the wiring conductor 9 connected to the portion away from the photoelectric conversion body L via the connecting member 8 on the portion where the lower electrode layer 2 of the photoelectric conversion portion 11 is extended. ing. Further, as shown in FIG. 3, the other end of the wiring conductor 9 is led out to the back surface through a hole 30 penetrating the substrate 1 in the vertical direction. As shown in FIG. It is connected to the inside of the terminal box 31 arranged on the back surface (non-light receiving surface). Then, the electrical output generated by the photoelectric conversion module 100 is led to an external circuit through the terminal box 31.

  As shown in FIG. 2, the photoelectric conversion unit 11 and the lead-out wiring unit 12 are sealed with a sealing material 13 and further covered with a cover member 14. In the photoelectric conversion module 100, a low moisture permeability member W having a moisture permeability lower than that of the sealing material 13 is interposed between the photoelectric conversion body L and the wiring conductor 9. With such a configuration, even if moisture enters the photoelectric conversion module 100 through the wiring conductor 9 from the outside, the entry of moisture into the photoelectric conversion unit 11 can be effectively reduced by the low moisture permeable member W. . As a result, the photoelectric conversion characteristics of the photoelectric conversion module 100 are maintained well and the reliability is high.

  About the moisture permeability of the sealing material 13 and the low moisture-permeable member W, it is JIS Z 0208 "moisture-proof packaging material moisture permeability test method (cup method)" with respect to the material used for the sealing material 13 and the low moisture-permeable member W It can be evaluated by the moisture permeability measured by a method based on the above.

Although the low moisture permeable member W may be in contact with the photoelectric converter L, from the viewpoint of enhancing the sealing property of the photoelectric converter L, the low moisture permeable member W is a photoelectric converter as shown in FIGS. The photoelectric conversion body L may be covered with the sealing material 13. Moreover, although the low moisture-permeable member W may be in contact with the wiring conductor 9 or may cover the wiring conductor 9, from the viewpoint of improving the sealing performance of the wiring conductor 9, as shown in FIGS. The low moisture permeable member W may be separated from the wiring conductor 9, and the wiring conductor 9 may be covered with the sealing material 13.

<Constituent members of photoelectric conversion module>
Next, each component of the photoelectric conversion module 100 described above will be described in detail.

  The substrate 1 is for supporting the photoelectric conversion unit 11. Examples of the material used for the substrate 1 include glass, ceramics, resin, and metal. As the substrate 1, for example, blue plate glass (soda lime glass) having a thickness of about 1 to 3 mm may be used.

  The lower electrode layer 2 (lower electrode layers 2a to 2d) is a conductor such as Mo, Al, Ti, or Au provided on the substrate 1. The lower electrode layer 2 is formed to a thickness of about 0.2 μm to 1 μm using a known thin film forming method such as sputtering or vapor deposition.

  The first semiconductor layer 3 (first semiconductor layers 3a to 3c) is a semiconductor layer having the first conductivity type. The first semiconductor layer 3 has a thickness of about 1 μm to 3 μm, for example. Although it does not specifically limit as a material of the 1st semiconductor layer 3, From a viewpoint that it has comparatively high photoelectric conversion efficiency, for example, I-III-VI group compound, I-II-IV-VI group compound, and II-VI Group compounds and the like may be used.

An I-III-VI group compound is a group consisting of a group IB element (also referred to as a group 11 element), a group III-B element (also referred to as a group 13 element), and a group VI-B element (also referred to as a group 16 element). A compound. Examples of the I-III-VI group compound include CuInSe ₂ (also referred to as copper indium selenide, CIS), Cu (In, Ga) Se ₂ (also referred to as copper indium selenide / gallium, CIGS), Cu ( In, Ga) (Se, S) ₂ (also referred to as diselene, copper indium sulphide, gallium, or CIGSS). Alternatively, the first semiconductor layer 3 may be composed of a multi-component compound semiconductor thin film such as copper indium selenide / gallium having a thin film of selenite / copper indium sulfide / gallium layer as a surface layer. The I-III-VI group compound has a relatively high light absorption coefficient, and good photoelectric conversion efficiency can be obtained even if the first semiconductor layer 3 is thin.

The I-II-IV-VI group compound includes an IB group element, an II-B group element (also referred to as a group 12 element), an IV-B group element (also referred to as a group 14 element), and a VI-B group element. It is a compound semiconductor. Examples of the I-II-IV-VI group compound include Cu ₂ ZnSnS ₄ (also referred to as CZTS) and Cu ₂ ZnSnS _4-x Se _x (also referred to as CZTSSe. Note that x is a number greater than 0 and smaller than 4. And Cu ₂ ZnSnSe ₄ (also referred to as CZTSe).

  The II-VI group compound is a compound semiconductor of a II-B group element and a VI-B group element. CdTe etc. are mentioned as a II-VI group compound.

  The second semiconductor layer 4 (second semiconductor layers 4 a to 4 c) is a semiconductor layer having a second conductivity type different from that of the first semiconductor layer 3. The second semiconductor layer 4 may be formed by stacking a material different from that of the first semiconductor layer 3 on the first semiconductor layer 3, or the surface portion of the first semiconductor layer 3 may be other than the first semiconductor layer 3. It may be modified by elemental doping. Further, a high resistance buffer layer or the like may be interposed between the first semiconductor layer 3 and the second semiconductor layer 4.

The second semiconductor layer 4 includes CdS, ZnS, ZnO, In ₂ S ₃ , In ₂ Se ₃ , In (OH, S), (Zn, In) (Se, OH), and (Zn, Mg) O. Etc. In this case, the second semiconductor layer 4 is formed with a thickness of 10 to 200 nm by, for example, a chemical bath deposition (CBD) method. In (OH, S) refers to a compound mainly containing In, OH, and S. (Zn, In) (Se, OH) refers to a compound mainly containing Zn, In, Se, and OH. (Zn, Mg) O refers to a compound mainly containing Zn, Mg and O.

  As shown in FIGS. 1 and 2, an upper electrode layer 5 may be further provided on the second semiconductor layer 4. The upper electrode layer 5 is a layer having a lower resistivity than the second semiconductor layer 4, and carriers generated in the first semiconductor layer 3 and the second semiconductor layer 4 are extracted well. From the viewpoint of further increasing the photoelectric conversion efficiency, the resistivity of the upper electrode layer 5 may be less than 1 Ω · cm and the sheet resistance may be 50 Ω / □ or less.

  The upper electrode layer 5 is a 0.05 to 3 μm transparent conductive film such as ITO or ZnO. In order to improve translucency and conductivity, the upper electrode layer 5 may be composed of a semiconductor having the same conductivity type as the second semiconductor layer 4. The upper electrode layer 5 can be formed by sputtering, vapor deposition, chemical vapor deposition (CVD), or the like.

  Further, as shown in FIGS. 1 and 2, a collecting electrode 6 may be further formed on the upper electrode layer 5. The collecting electrode 6 is for taking out the carriers generated in the first semiconductor layer 3 and the second semiconductor layer 4 more satisfactorily. For example, as shown in FIG. 1, the collector electrode 6 is formed in a linear shape from one end of the photoelectric conversion cell 10 to the connection conductor 7. As a result, the current generated in the first semiconductor layer 3 and the fourth semiconductor layer 4 is collected to the current collecting electrode 6 via the upper electrode layer 5, and to the adjacent photoelectric conversion cell 10 via the connection conductor 7. Good conductivity.

  The collector electrode 6 may have a width of 50 to 400 μm from the viewpoint of increasing the light transmittance to the first semiconductor layer 3 and having good conductivity. The current collecting electrode 6 may have a plurality of branched portions.

  The current collecting electrode 6 is formed, for example, by printing a metal paste in which a metal powder such as Ag is dispersed in a resin binder or the like in a pattern and curing it.

  1 and 2, the connection conductor 7 is a conductor provided in a groove that penetrates the first semiconductor layer 3, the second semiconductor layer 4, and the second electrode layer 5. The connection conductor 7 can be made of metal, conductive paste, or the like. In FIG. 1 and FIG. 2, the collector electrode 6 is extended to form the connection conductor 7, but the present invention is not limited to this. For example, the upper electrode layer 5 may be stretched.

  The connection member 8 is for connecting the wiring conductor 9 to the lower electrode layer 2 satisfactorily. The connecting member 8 is formed, for example, by printing a metal paste in which a metal powder such as Ag is dispersed in a resin binder or the like in a pattern and curing it.

  Examples of the wiring conductor 9 include a metal foil such as copper (Cu) having a thickness of about 0.1 to 0.5 mm and a width of about 1 to 7 mm. Also. The surface of the metal foil may be coated with tin, nickel, solder, or the like by plating or the like in order to improve electrical connection with the lower electrode layer 2 or the connection member 8.

  The sealing material 13 is for protecting the photoelectric conversion unit 11, and examples thereof include a resin mainly composed of copolymerized ethylene vinyl acetate (EVA) and a resin mainly composed of polyvinyl butyral.

As the low moisture permeable member W, a member having lower moisture permeability than the sealing material 13 is used. As the low moisture-permeable member W, a resin such as polyethylene, an elastic body made of rubber such as butyl rubber or ethylene propylene rubber, or a mixture of the above-described resin and rubber may be used. Further, as the low moisture permeable member W, a material in which an adsorbent is dispersed in a polymer material may be used. As such an adsorbent, those having the property of chemically adsorbing moisture may be used, or those having the property of physically adsorbing moisture may be used. The adsorbent that chemically adsorbs moisture has a property of chemically adsorbing with moisture and chemical reaction. For example, calcium oxide (CaO), sodium oxide (Na ₂ O), magnesium oxide (MgO), chloride calcium (CaCl _2), anhydrous sodium sulfate _(Na 2 _SO 4), and the like copper sulfate anhydrous salt (CuSO ₄₎ or calcium sulfate (CaSO _4). An adsorbent that physically adsorbs moisture adsorbs moisture by van der Waals force generated between the surface of the adsorbent and moisture. For example, molecular sieves such as zeolite, silica gel (SiO ₂ .nH ₂ O), inorganic materials having a porous surface such as alumina, allophane or activated carbon.

  From the viewpoint of enhancing the durability of the photoelectric conversion module 100 by increasing the adhesive force of the sealing material 13 and further reducing the penetration of moisture into the photoelectric conversion unit 11, the sealing material 13 is a thermosetting resin. The low moisture permeable member may be a thermoplastic resin. Examples of such thermosetting resins include thermosetting EVA. Moreover, butyl rubber etc. are mentioned as such a thermoplastic resin.

<Other examples of photoelectric conversion module>
Next, another example of the photoelectric conversion module will be described. FIG. 5 is a cross-sectional view showing another example of the photoelectric conversion module. In the photoelectric conversion module 200 shown in FIG. 5, parts having the same configuration as the photoelectric conversion module 100 shown in FIGS. The photoelectric conversion module 200 further includes a second low moisture permeable member W2 having a moisture permeability lower than that of the sealing material 13 on the opposite side of the wiring conductor 9 from the photoelectric converter L. This is different from the photoelectric conversion module 100. With such a configuration, moisture intrusion can be further reduced.

  The second low moisture permeable member W2 may be a member having lower moisture permeability than the sealing material 13, and the members exemplified in the low moisture permeable member W may be used.

  The second low moisture permeable member W2 may be in contact with the wiring conductor 9, but from the viewpoint of improving the sealing performance of the wiring conductor 9, the second low moisture permeable member W2 is as shown in FIG. It may be separated from the wiring conductor 9.

  In the photoelectric conversion module 200, the low moisture permeable member W includes a first adsorbent that chemically adsorbs moisture, and the second low moisture permeable member W2 includes a second adsorbent that physically adsorbs moisture. Also good. With such a configuration, the intrusion of moisture into the photoelectric conversion unit 11 can be reduced over a longer period. That is, moisture entering from the outside is first physically adsorbed by the second adsorbent contained in the second low moisture permeability member W2. In physical adsorption, moisture is adsorbed by van der Waals force generated between the surface of the adsorbent and moisture, so that the adsorption force is weaker than chemical adsorption. Therefore, the second adsorbent has a function of desorbing moisture depending on conditions such as temperature and humidity, and is desorbed from the second adsorbent when a predetermined condition is reached. Therefore, the second adsorbent can reversibly adsorb and desorb moisture, and can maintain the effect of reducing moisture ingress over a long period of time. On the other hand, the desorbed moisture may be directed not only to the outside of the photoelectric conversion module 200 but also to the inside (photoelectric conversion unit 11 side). Such moisture toward the photoelectric conversion unit 11 side is chemically adsorbed by the first adsorbent of the low moisture permeability member W. Since chemical adsorption adsorbs moisture with chemical reaction with moisture, moisture is more strongly adsorbed. Therefore, the infiltration of moisture into the photoelectric conversion unit 11 is further reduced.

  Note that the present invention is not limited to the above-described embodiment, and various modifications may be made without departing from the scope of the present invention. In the photoelectric conversion modules 100 and 200, an example in which the photoelectric conversion cells 10 in the photoelectric conversion unit 11 are three rows is shown, but the present invention is not limited thereto, and may be one row, two rows, or four rows or more.

1: substrate 2, 2a, 2b, 2c, 2d: lower electrode layer 3, 3a, 3b, 3c: first semiconductor layer 4, 4a, 4b, 4c: second semiconductor layer 5: upper electrode layer 6: collection Electrode 7: Connection conductor 8: Connection member 9: Wiring conductor 10: Photoelectric conversion cell 11: Photoelectric conversion part 12: Lead-out wiring part 13: Sealing material 14: Cover member L: Photoelectric conversion body W, W2: Low moisture permeability Member 100, 200: Photoelectric conversion module

Claims (6)

A substrate,
A photoelectric conversion body provided on the substrate;
A wiring conductor for taking out an electrical output generated by the photoelectric converter, which is located on the substrate away from the photoelectric converter,
A sealing material for sealing the photoelectric converter;
A photoelectric conversion module comprising: a low moisture permeability member having a moisture permeability lower than that of the sealing material, which is interposed between the photoelectric conversion body and the wiring conductor.   The photoelectric conversion module according to claim 1, wherein the low moisture-permeable member is separated from the photoelectric conversion body.   The photoelectric conversion module according to claim 1, wherein the low moisture-permeable member is separated from the wiring conductor.   The photoelectric conversion module according to claim 1, wherein the sealing material is a thermosetting resin, and the low moisture permeable member is a thermoplastic resin.   5. The device according to claim 1, further comprising a second low moisture-permeable member that is located on the opposite side of the wiring conductor from the photoelectric conversion body and has a moisture permeability lower than that of the sealing material. The photoelectric conversion module as described.   6. The low moisture-permeable member includes a first adsorbent that chemically adsorbs moisture, and the second low moisture-permeable member includes a second adsorbent that physically adsorbs moisture. Photoelectric conversion module.

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