JP2006294695A - Withstand voltage testing method of solar cell module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of carrying out a withstand voltage test of a solar cell module rapidly and safely without misjudgment. <P>SOLUTION: The solar cell module includes a solar cell panel which is sealed by a protection film having a multilayered structure including a conductive metal layer and has a power output terminal, a metal frame for pinching the solar cell panel, and/or a metal plate to place the solar cell panel on. In testing the withstand voltage of the solar cell module, electrical continuity is established between the conductive metal layer and the metal frame and/or the metal plate and then voltage is applied between the power output terminal and the metal frame and/or the metal plate. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a withstand voltage test method which is a kind of inspection method for solar cell modules.

  In order to confirm or inspect the safety of the solar cell module, a withstand voltage test is often used. This method is described in JIS C8918, JIS C8939, and the like. According to these, the withstand voltage test method of the solar cell module is as follows: “The output terminal of the module is short-circuited, and a withstand voltage tester between the terminal and the frame or the ground terminal is used, and a DC voltage that is twice the maximum system voltage + 1000V is Apply for minutes. "

  On the other hand, the shape of the solar cell module has been diversified from the viewpoints of progress in construction technology and improvement in design. Generally, a frame such as an aluminum frame is attached around the solar cell panel, but there is also a so-called roof material integrated type attached to a metal plate or the like with a metal fitting, a double-sided tape, or an adhesive. In particular, in the latter case, there is a solar cell panel that does not have a special treatment such as a waterproof seal at the end.

  When it is going to implement the said withstand voltage test to these solar cell modules, it is common to select a metal plate as the said frame which applies a voltage in an withstand voltage test. However, a spark may occur between this metal plate and the metal fitting for assembling it on the solar cell panel, or between this metal plate and the metal contained in the protective film of the solar cell panel. There are problems such as ensuring safety against damage and damage to the solar cell module itself.

  In addition to the problem of the occurrence of such sparks, there is a problem that the withstand voltage performance cannot be correctly evaluated due to a transient current flowing at the start of the withstand voltage test. If a phenomenon of sparks or a transient current occurs during a withstand voltage test, it is often not easy to distinguish between these phenomena and the breakdown of the solar cell module, and an inspection is necessary to conduct a re-inspection. There are also problems that the process becomes complicated, and that the non-defective product is erroneously determined as a defective product and the yield of the product is lowered.

Devices relating to such a withstand voltage test are described in Japanese Patent Laid-Open Nos. 7-235658 and 2004-47838. By using these devices, it is possible to suppress the generation of sparks based on the electric power generated by the solar cell module itself irradiated with light during connection for withstand voltage testing, Although the output characteristics can be measured together with the withstand voltage test, the above-mentioned problems are solved for the withstand voltage test itself, and further, the essential insulation performance of the solar cell module itself is not misjudged. There is no description of a technique according to the present invention that enables safe measurement.
JP-A-7-235658 JP 2004-47838 A JIS C8918 Crystalline solar cell module JIS C8939 amorphous solar cell module

  In view of the above-mentioned problems, the problem to be solved by the present invention is to provide a method for performing a withstand voltage test of a solar cell module quickly, reliably and safely.

  The withstand voltage test method for a solar cell module of the present invention is a solar cell panel sealed with a protective film having a multilayer structure including a conductive metal layer and having a power output terminal, and sandwiches the solar cell panel A withstand voltage test method for a solar cell module including a metal frame and / or a metal plate on which the solar cell panel is placed, wherein the conductive metal layer is interposed between the metal frame and / or the metal plate. Is a withstand voltage test method for a solar cell module, in which a voltage is applied between the power output terminal and the metal frame and / or the metal plate while being electrically connected. By adopting this method, when a voltage is applied in a withstand voltage test, there is electrical continuity between a conductive metal layer constituting a protective film used as a sealing material for a solar cell panel and a metal frame or a metal plate. Since the charge transfer between the members is possible, the occurrence of a spark or the like can be suppressed. In addition, the potential of the metal frame and / or the metal plate, the conductive metal layer, and the solar cell panel when the voltage is applied to each other can be maintained in a constant state suitable for the withstand voltage test. Variations between solar cell modules can be suppressed.

  In the solar cell module provided for the withstand voltage test method of the present invention, at least after the test, the conductive metal layer and the metal frame and / or the metal plate are electrically insulated. It is preferable from the point which improves the insulation of a solar cell module.

  Further, as a method for conducting the electrical connection, a conductive material having a volume resistivity of 10,000 Ωcm or less is interposed between the conductive metal layer and the metal frame and / or the metal plate. It is preferable. By using a conductive material having a volume resistivity of 10,000 Ωcm or less, a transient current during a withstand voltage test can be reduced, and occurrence of erroneous determination can be suppressed.

  Furthermore, the conductive material is preferably composed mainly of water, and since it is a liquid, it is excellent in shape followability, easy to ensure safety, and also prevents adverse effects on the solar cell panel. it can.

  Such a withstand voltage test method for a solar cell module according to the present invention includes a step of boosting at least a voltage to a predetermined value at a constant boosting time in the voltage application, the power output terminal, the metal frame, and / or the voltage application. It is particularly effective in a withstand voltage test method for a solar cell module including at least a step of measuring a test current value flowing between the metal plate and a step of comparing the test current value with a preset determination current value. . Conventionally, the test current value was judged to be defective when it instantaneously exceeded the judgment current value, so even if it was a non-defective product, it was judged as a defective product regardless of the essential insulation performance of the solar cell module itself. However, by using the withstand voltage test method of the present invention, the transient current characteristics are measured in advance for the same type of solar cell modules, and the withstand voltage test conditions are set appropriately based on the results. By doing so, the accuracy of the good / bad determination can be improved.

  Further, a maximum transient current value in the boosting step is measured in advance for a solar cell module equivalent to a solar cell module to be tested in a withstand voltage test so that the maximum transient current value does not exceed the determination current value. The withstand voltage test condition can be set by setting the boost time.

  On the other hand, as another method for setting the withstand voltage test condition, a method of not performing the comparison during the boosting time is also effective, thereby avoiding erroneous determination due to transient current during boosting, which is a problem. At the same time, the test can be performed quickly without adjusting the boosting time.

  According to the withstand voltage test method for a solar cell module of the present invention, it is possible to suppress the occurrence of sparks occurring at a portion that is essentially unrelated to the withstand voltage performance of the solar cell module, It is possible to maintain the potential of the plate, conductive metal layer, and solar cell panel when they are applied with voltage in a certain state suitable for the withstand voltage test. Can be suppressed. As a result, it is possible to efficiently detect a defect such as a defective withstand voltage and to omit a complicated process such as a re-inspection. In addition, since there is no occurrence of sparks, inspection work can be carried out safely and excessive current can be prevented from flowing through the withstand voltage tester.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In each drawing of the present application, dimensional relationships such as thickness and length are appropriately changed for clarity and simplification of the drawings, and do not necessarily represent actual dimensional relationships.

  As a typical example of a solar cell panel, FIG. 1 shows a cross section of a thin-film silicon solar cell panel. The solar cell panel of FIG. 1 is obtained by using a glass substrate 11, a photoelectric conversion element 12, a filler 13, and a protective film 14 as basic constituent members and bonding them together by, for example, a vacuum laminating method. FIG. 1 shows an example of a cross section of a thin-film silicon solar cell panel. In a crystalline silicon solar cell and a solar cell composed of other photoelectric conversion elements, the thin film silicon solar cell panel is bonded with a filler or a protective film. The effect of the present invention is the same if the structure is similar.

  Here, the glass substrate 11 is mainly made of float glass. As the photoelectric conversion layer of the photoelectric conversion element 12, thin film silicon, thin film polycrystalline silicon, or the like can be used.

  In general, the protective film has a multilayer structure in which a resin layer and an Al foil that is a conductive metal layer are laminated, and the photoelectric conversion element 12 is electrically insulated from the outside, and moisture and moisture from the outside Sealed to prevent moisture from entering. As the conductive metal layer, aluminum or steel plate is often used, and its function is to suppress moisture and moisture from the outside. Therefore, the conductive metal layer is inserted over the entire protective film. The withstand voltage test method for a solar cell module of the present invention particularly relates to a withstand voltage test method for a solar cell module including a solar cell panel sealed with a protective film including the conductive metal layer. Moreover, as a resin layer, a fluorine-type film, a polyester-type film, etc. are mainly used.

  Next, FIG. 2 shows a cross-sectional structure of the solar cell module and a wiring structure in the withstand voltage test of the present invention. The details of the solar cell panel 21 are simplified from those shown in FIG. A metal plate 22 is attached to the solar cell panel 21 on the side opposite to the light receiving surface. Electricity generated in the solar cell panel is taken out from the solar cell panel by wiring, penetrates through the opening of the metal frame 22, and is joined to the terminal box 23 having an output terminal and an output cable. Although there is no restriction | limiting in particular about the internal wiring of a solar cell panel, and the material of a cable, The thing which uses copper foil or a copper wire as a main material from the surface of an electrical resistance or a price is used suitably.

  In a solar cell module, aluminum is often used as a material for a metal frame that sandwiches a solar cell panel. This metal frame is used to increase the mechanical strength of the solar cell panel and to attach the solar cell module to a frame or the like.

  Moreover, in a solar cell module, aluminum, a steel plate, etc. are used as a material of the metal plate in which a solar cell panel is mounted. This metal plate is used to increase the mechanical strength of the solar cell panel and to attach the solar cell module to a mount, etc. In addition, the metal plate itself acts as a roofing material with improved waterproofness and fire resistance. .

These metal frames and / or metal plates are assembled to the solar cell panel using gaskets, double-sided tapes, adhesives, auxiliary metal fittings, screws or the like (hereinafter referred to as assembly members). In addition, if the metal part of the assembly member and the solar cell panel are in physical contact, the solar cell module may be damaged due to physical impact during assembly, transportation, and installation. When a part and a solar cell panel contact, the local temperature difference will generate | occur | produce in the glass of a solar cell panel, and glass may be damaged. For this reason, the metal part of these assembly members and the conductive metal layer are generally electrically insulated. With regard to the withstand voltage test method for the solar cell module, 21, 22, and 23 are integrated. The solar cell module is immersed in the container 25 containing the conductive material 24, and the positive side of the cable 27 coming out of the withstand voltage tester 26 is connected to both the positive and negative poles of the output cable in the terminal box 23. The negative side of 27 is connected to the metal plate 22 of the solar cell module. Note that the plus / minus selection of the withstand voltage tester may be reversed in the present invention, but if the insulation of the container 25 containing the conductive material 24 is not sufficient, the container 25 can be connected to the outside of the test system. Since there is a possibility of electric leakage, the side connected to the metal plate 22 is preferably selected from the side connected to the ground of the withstand voltage tester. In consideration of safety and test accuracy, it is preferable to select a highly insulating material for the container 25.

  The withstand voltage measuring method of the solar cell module of the present invention applies a voltage between the power output terminal and the metal frame and / or the metal plate, measures the test current value flowing between them, and obtains the test current value obtained. And a withstand voltage test method for comparing a preset judgment current value. Specifically, in the withstand voltage test, both the positive and negative terminals, which are the power output terminals of the solar cell module, are short-circuited between these terminals, and the short-circuited power output terminal is connected to the positive electrode of the withstand voltage tester, The test is performed by applying a voltage to the negative electrode of the test machine in contact with any of the metal frame, metal plate, or conductive material of the solar cell module.

  In the method of the present invention, a voltage is applied while electrically conducting between the conductive metal layer and the metal frame and / or the metal plate. At this time, for the purpose of this electrical conduction, a conductive material having a volume resistivity of 10,000 Ωcm or less is preferably interposed between the conductive metal layer and the metal frame and / or the metal plate, in particular, 3500 Ωcm. The following is more preferable.

  In addition, when a material containing water as a main component is used as the conductive material, an electrolyte or the like is generally added as a means for setting the volume resistivity to a desired value. Is preferred. If an acid, an alkali, or the like is added more than necessary as the electrolyte, it is not preferable because the protective film of the solar cell panel, the metal frame, or the metal plate may be dissolved or altered. In addition, if the volume resistivity is in a desired region, it can be used as it is.

  When conducting a withstand voltage test, a conductive material may be interposed between the conductive metal layer of the protective film of the solar cell module and the metal frame and / or metal plate. A method in which a part of the solar cell module is immersed in a predetermined container and immersed in the container is appropriate. In this case, it is sufficient that a part of the protective film of the solar cell module and a part of the metal frame and / or the metal plate are in contact with the conductive material, and it is necessary to immerse the entire solar cell module in the conductive material. Absent.

  In addition, the withstand voltage tester used in the present invention may be a commercially available one, and may have a function capable of applying a predetermined voltage for a certain period of time. In general, in a withstand voltage test of a solar cell module, the determination current value may be set as small as several μA from the viewpoint of strictly examining the safety of the solar cell. In many cases, a voltage of 2000 to 3000 V is applied as a test voltage in the withstand voltage test. A transient current during a withstand voltage test in a solar cell module is often generated at the time of boosting, and generally shows several μA to several tens of μA. If this transient current exceeds the determination current, an erroneous determination is caused. For this reason, a tester in which the boosting time can be set so as not to exceed the determination current by increasing the boosting time is preferable. Regarding the boosting time, although it depends on the type of the solar cell and the magnitude of the judgment current, it is not preferable from the viewpoint of workability to boost the pressure for a long time of 1 minute or longer.

  In addition, as a precondition for determining the pass / fail time quickly and accurately by setting the boosting time appropriately, the maximum transient current value is measured in advance for the solar cell module equivalent to the solar cell module of the withstand voltage test under the condition including the boosting step. It is preferable to keep it.

  On the other hand, as another method of setting the withstand voltage test conditions, when using a method of not performing the comparison during the boosting time, the test voltage of the withstand voltage tester is set as a specific method. There is a method of performing a withstand voltage test using a testing machine provided with a control circuit so that the current value during the boosting time is not determined when boosting to a value.

  As a specification of the withstand voltage tester in the present invention, in addition to the determination current value at the time of the test, the determination current at the time of boosting can be set separately or the circuit is set so as not to be determined. Moreover, it is preferable that the determination current at the time of boosting can be set separately from the viewpoint of safety when a defective solar cell module to be determined in this test is tested.

  As specific examples of the above-described embodiment, several examples will be described below together with comparative examples.

  The withstand voltage test method of the present invention will be described with reference to FIG. A solar cell panel 21 and a metal plate 22 that is substantially the same type as the solar cell panel are bonded together with a double-sided tape, and an output cable 23 including a power output terminal taken out from the solar cell panel on the back side of the metal plate is a basic configuration. . A part of this solar cell module is immersed in a container 25 containing a conductive material 24. At this time, the end portion of the protective film in the solar cell panel 21 and the metal plate 22 are each in contact with the conductive material 24. Using the cable 27, both terminals of the solar cell module and the metal plate 22 are connected to the withstand voltage tester 26, respectively.

  Each Example and each comparative example were implemented using the solar cell module described below.

  First, as a solar cell panel, an integrated amorphous / microcrystalline silicon tandem solar cell is provided on a surface opposite to the light receiving surface on a float glass plate having a length of 450 mm, a width of 910 mm, and a thickness of 4 mm. I used what is. Here, in order to take out the electricity generated by the solar cell panel, the positive and negative electrodes are taken out from both ends of the integrated amorphous / microcrystalline silicon tandem solar cell by solder plating body foil (width 2 mm and 6 mm). Yes.

  Next, an ethylene-vinyl acetate copolymer (thickness 0.4 mm) is used as a filler on the element surface of the glass with a photoelectric conversion element, and a protective film including a conductive metal layer thereon is used as terephthalate. An acid-ethylene glycol polycondensate (PET, thickness 50 μm), an aluminum foil (thickness 50 μm), and a polyvinylidene fluoride (thickness 38 μm) three layers are placed, and these are vacuum laminators, etc. Was used for thermocompression bonding. At this time, the conductive metal layer of the protective film of the solar cell was not electrically contacted with the above-described solder-plated copper foil as the positive and negative take-out electrodes. Such a solder-plated copper foil for electrical extraction of the solar cell panel is connected to the back surface of the solar cell module, that is, the terminal box attached on the protective film, and connected to an output cable having positive and negative connectors. .

  As the metal plate on which the solar cell panel is placed, a galvalume steel plate having a thickness of 0.5 mm, a length of 470 mm, and a width of 910 mm was used. The solar cell panel and the steel sheet are bonded with an acrylic double-sided tape having a thickness of 1 mm and a width of 10 mm and a moisture-curing silicone adhesive. The shortest distance in the space between the conductive metal layer contained in the protective film of the solar cell panel and the galvanium steel sheet is about 1 mm. Hereinafter, the solar cell module having this structure is referred to as a metal plate type solar cell module.

  As the metal frame for sandwiching the solar cell panel, an extruded product of an aluminum frame was used. A resin gasket (ethylene-propylene thermoplastic resin) is sandwiched between the solar cell panel and the aluminum frame, and the four aluminum frames are fastened with stainless steel screws. The size of the solar cell module is 920 mm long, 465 mm wide, and 40 mm thick. The shortest distance in the space between the conductive metal layer contained in the protective film of the solar cell panel and the aluminum frame is about 3 mm. Hereinafter, the solar cell having this structure is referred to as a metal frame solar cell module.

Example 1
Water having a volume resistivity of 2000 Ωcm was placed in a water tank to a depth of about 5 cm. One side of the short side of the metal plate solar cell module was immersed in this water tank. The test voltage of the withstand voltage tester is 2.0 kV, the boosting time for boosting to this voltage is 20 seconds, the voltage application time after boosting is 1 minute, the judgment current after boosting is 40 μA, and the method shown in FIG. A withstand voltage test was performed. The test proceeded without problems and was judged as normal. The maximum transient current value during boosting, which is the maximum transient current value, was 30 μA, and the current value during the test was 3 to 7 μA.

(Comparative Example 1)
A withstand voltage test was performed under the same conditions as in Example 1 except that the solar cell module having the same structure as that used in Example 1 was used and the module was not immersed in water. As a result, a minute spark was observed between the solar cell panel and the metal plate during the pressurization, and the test was interrupted (when this solar cell module was retested according to the method of Example 1, no spark was observed. Determined to be normal).

(Comparative Example 2)
A withstand voltage test was performed under the same conditions as in Example 1 except that the solar cell module having the same structure as that used in Example 1 was used and the volume resistivity of water in the water tank was set to 14700 Ωcm. As a result, the determination current exceeded 40 μA during the boosting and was determined to be unacceptable. (When this solar cell module was retested according to the method of Example 1, the maximum value of the transient current was 30 μA and was determined to be a normal product. Was).

(Comparative Example 3)
A withstand voltage test was performed under the same conditions as in Example 1, except that a solar cell module having the same structure as that used in Example 1 was used and the voltage boost time of the withstand voltage tester was set to 10 seconds. As a result, the maximum value of the transient current at the time of boosting exceeded 40 μA and was determined to be unacceptable. (When this solar cell module was retested according to the method of Example 1, the maximum value of the transient current was 30 μA, which is normal. It was judged as an article).

(Example 2)
Withstand voltage test under the same conditions as in Example 1 except that a solar cell module having the same structure as that used in Example 1 was used, the withstand voltage tester was set to 40 seconds and the judgment current after boosting was 20 μA. Carried out. As a result, the test proceeded without any problem and was determined to be normal. The maximum value of the transient current during boosting was 16 μA, and the current value during the test was 3 to 7 μA.

(Example 3)
Using a solar cell module having the same structure as that used in Example 1, the test voltage of the withstand voltage tester is 2.0 kV, the boosting time is 20 seconds, the judgment current at the time of boosting is 200 μA, and the voltage application time after boosting is The withstand voltage test was performed by the method shown in FIG. The test proceeded without problems and was judged as normal.

  As in Example 1, it is possible to suppress the occurrence of transient currents and sparks by conducting a withstand voltage test while electrically conducting between the conductive metal layer of the solar cell panel and the metal plate. As a result, the withstand voltage test could be carried out reliably.

  On the other hand, when the metal layer and the metal plate are not electrically connected as in Comparative Example 1 or when the volume resistivity of the conductive material exceeds 10,000 Ω as in Comparative Example 2, the transient current or The occurrence of a spark sometimes caused a false determination regardless of the withstand voltage performance of the solar cell panel.

  Further, as can be seen by comparing Comparative Example 3, Example 2, and Example 3, the accuracy of good / bad judgment can be improved by changing the boost time and judgment current, and the withstand voltage test can be performed. It can be implemented reliably.

Sectional view of a solar cell panel as a representative example of the present invention Solar cell module as representative example of the present invention, and method of withstanding voltage test

Explanation of symbols

11 Transparent substrate 12 Photoelectric conversion element 13 Filler 14 Protective film (lamination of metal and resin)
21 Solar Panel 22 Metal Plate 23 Terminal Box and Output Cable 24 Conductive Material 25 Container 26 Withstand Voltage Tester Body 27 Cable

Claims (6)

A solar cell panel sealed with a protective film having a multilayer structure including a conductive metal layer and provided with a power output terminal, a metal frame sandwiching the solar cell panel, and / or the solar cell panel is placed A withstand voltage test method for a solar cell module including a metal plate,
Applying a voltage between the power output terminal and the metal frame and / or the metal plate while electrically conducting the conductive metal layer and the metal frame and / or the metal plate. A withstand voltage test method for a solar cell module.   It is a withstand voltage test method of the solar cell module of Claim 1, Comprising: Between the said electroconductive metal layer and the said metal frame and / or the said metal plate, the electroconductive material whose volume resistivity is 10000 ohm-cm or less is provided. A withstand voltage test method for a solar cell module, wherein the electrical connection is made by interposing.   The withstand voltage test method for a solar cell module according to claim 2, wherein the conductive material contains water as a main component. A withstand voltage test method for a solar cell module according to any one of claims 1 to 3,
Boosting at least a voltage to a predetermined value in a constant boosting time in the voltage application;
Measuring a test current value flowing between the power output terminal and the metal frame and / or the metal plate when the voltage is applied;
A step of comparing the test current value with a preset determination current value;
A withstand voltage test method for a solar cell module including at least   It is the withstand voltage test method of the solar cell module of Claim 4, Comprising: The maximum transient current value in the said pressure | voltage rise process is previously measured about the solar cell module equivalent to the said solar cell module, and this maximum transient current value is The withstand voltage test method for a solar cell module, wherein the boost time is set so as not to exceed the determination current value.   5. The withstand voltage test method for a solar cell module according to claim 4, wherein no comparison is made during the boosting time.

Images