JP2013093356A - Inspection apparatus and inspection method of solar cell module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an inspection method and an inspection apparatus of a solar cell module capable of detecting deterioration of a sealant in a solar cell module appropriately and reliably, and evaluating the life thereof.SOLUTION: The inspection apparatus includes light projection means 21 for irradiating a plurality of measuring points in a solar cell module to be inspected with laser light in order to determine the degree of deterioration of sealants 13, 14 in a solar cell module (solar cell panel 10) having one or more solar cells 18, spectral means 24 for obtaining a spectrum by spectroscopy of Raman scattered light from the inspection object at the measuring points, and spectrum analysis means 25 for analyzing the state of the solar cell at the measuring points from the spectrum of Raman scattered light obtained by the spectral means. At least one of the measuring points is located on the periphery of the sealant in the solar cell module.

Description

  The present invention relates to a solar cell module that performs life evaluation of a solar cell module by detecting the degree of deterioration of a sealing material in the solar cell module in a solar cell module including at least one solar cell. The present invention relates to an apparatus and an inspection method thereof.

  Silicon type solar cells and thin film type solar cells are conventionally known as methods of utilizing solar energy. In performing performance evaluation, life evaluation, and the like of this type of solar cell, there is a demand for a method and apparatus for detecting defects due to manufacturing and detecting the degree of deterioration due to use.

  2. Description of the Related Art Conventionally, techniques and apparatuses for inspecting defects of solar cells of a solar cell module by an EL light emission method, a thermography method, or the like have been proposed. However, no technique or inspection device for evaluating the degree of deterioration of the sealing material in the solar cell module has been proposed.

  The degree of deterioration of the sealing material for the solar cell module can be analyzed by IR (infrared spectroscopy) for the sealing material alone, but to measure as a solar cell module, it is measured through the cover glass of the solar cell module. There is a need to. However, since IR (infrared spectroscopy) is absorbed by the cover glass, it cannot be measured through the cover glass.

Here, the necessity for evaluating the degree of deterioration of the sealing material is as follows.
That is, in the solar cell module, the conditions for laminating with the sealing material are determined based on the evaluation standard that the degree of gelation by the xylene method exceeds 70%, and if it is lower than this, it is not adopted.
On the other hand, there is a need on the production site that the cross-linking reaction is advanced at a high temperature quickly in order to shorten the tact time.

For example, if the solar cell module is heated to an extremely high temperature during laminating, the cover glass warps on the hot plate of the laminator, and only the central part comes into contact with the hot plate and the peripheral part is lifted, so the center is fast. Although the cross-linking reaction has started, the temperature rise is delayed in the peripheral portion of the cover glass, and there are cases where the cross-linking is insufficient.
In order to complete the reaction including the periphery of the cover glass, there is also a method of additional heating in a curing furnace, but the reaction proceeds in atmospheric pressure air and the central part receiving a stronger thermal history is deteriorated. Was concerned that it would progress.

However, since the analysis method using IR or the like cannot evaluate the deterioration of the sealing material through the measurement through the cover glass, the causal relationship between the lamination condition and the deterioration of the sealing material has not been known so far. In addition, the power generation performance cannot be judged because it does not change even with an abnormal heat history immediately after production. Furthermore, since the sealing material that has received the thermal history is accelerated over time, power generation performance is reduced due to discoloration of the sealing material.
And when the used used solar cell module is seen, discoloration is confirmed in the central part of the sealing material.

  Therefore, in this type of solar cell module, it is desired to take some measures for the detection device and the detection method for detecting the degree of deterioration of the sealing material through the glass from the outside of the solar cell module.

  The present invention has been made in view of such circumstances, and by appropriately and reliably detecting the degree of deterioration of the sealing material in the solar cell module through the glass, the lifetime evaluation of the solar cell module can be appropriately performed. An object of the present invention is to provide a solar cell module inspection apparatus and inspection method that can be reliably performed.

  An inspection device for a sealing material in a solar cell module according to a first invention for achieving the above object is an inspection for determining a degree of deterioration of a sealing material in a solar cell module having one or more solar cells. A light-projecting means for irradiating a plurality of measurement points in a solar cell module to be inspected with laser light, and a spectrum for obtaining a spectrum by spectroscopic analysis of Raman scattered light scattered from the inspection object at the measurement points And a spectrum analyzing means for analyzing the state of the solar cell at the measurement point from the spectrum of the Raman scattered light obtained by the spectroscopic means, and at least one of the measurement points is within the solar cell module. It is set so that it may be located in the peripheral part of a sealing material.

  According to the first invention, in determining the degree of deterioration of the sealing material, a plurality of measurement points such as a peripheral portion of the sealing material are appropriately detected by Raman spectroscopy by irradiating laser light from the outside of the solar cell module. It is possible to reliably detect and grasp the degree of deterioration by the spectrum analysis, and thereby it is possible to reliably evaluate the life of the solar cell module.

  The inspection apparatus for a sealing material according to a second aspect of the present invention is characterized in that, in the first aspect, the measurement point is specified by using a positioning means in three axial directions of x, y, and z.

  According to the second invention, since the measurement points are positioned and specified in the three axis directions of x, y, and z, each solar cell module can be detected with high accuracy, It is possible to reliably grasp the degree of deterioration of the sealing material and appropriately evaluate the lifetime of the module.

  According to a third aspect of the present invention, there is provided the inspection apparatus for a sealing material according to the first aspect or the second aspect, wherein the solar cell module electrically connects a plurality of solar cells and arranges the sealing material in a plane. A solar cell module having a laminate structure in which a transparent protective layer and a back sheet are sandwiched between the front and back.

  According to the third invention, in the solar cell module having a laminate structure, the degree of deterioration of the sealing material is detected through the cover glass, and the inspection device evaluates the degree of deterioration of the sealing material in the solar cell module. The function can be sufficiently effective.

  Moreover, the inspection method of the sealing material in the solar cell module according to the fourth aspect of the invention for achieving the above object determines the degree of deterioration of the sealing material in the solar cell module having one or more solar cells. A method of identifying a plurality of measurement points positioned in the three-axis directions of x, y, and z on a solar cell module to be inspected, and a laser focused on each measurement point A step of irradiating light, a step of obtaining a spectrum by dispersing Raman scattered light scattered from an inspection object at the measurement point, and a step of detecting the state of the sealing material in the solar cell module at each measurement point And a step of analyzing the degree of deterioration of the sealing material and evaluating the lifetime of the solar cell module.

  According to the fourth invention, the degree of deterioration of the sealing material in the solar cell module can be detected through the cover glass, and the same effect as in the first invention can be exhibited.

  According to the inspection apparatus and the inspection method for a solar cell module according to the present invention, the degree of deterioration of the sealing material in the solar cell module is appropriately and reliably detected and grasped from the outside of the solar cell module through the glass. As a result, it is possible to correctly detect and grasp the progress of the deterioration of the sealing material due to the deterioration of the sealing performance in the laminating process, and as a result, the life evaluation of the solar cell module is accurately performed by nondestructive inspection. be able to.

  In particular, according to the present invention, since the degree of deterioration of the internal sealing material can be detected with the solar cell module as it is, the existing solar cell module can be removed and non-destructively inspected. It is possible to grasp the degree of deterioration of the stopping material, perform its life evaluation appropriately and reliably, and exhibit various excellent effects from a practical aspect such as being able to confirm the service life.

It is the figure which showed typically the structure of the solar cell module as a test object, (a) is a top view, (b) is an exploded sectional view which shows a laminated structure. It is the top view which looked at one photovoltaic cell from the light-receiving surface. It is a figure which shows schematic structure of the inspection apparatus of the solar cell module which concerns on this invention. It is an enlarged view of the inspection apparatus by Raman spectroscopy characterizing the present invention. It is a characteristic view which shows the relationship between the spectrum intensity | strength when a flow Braman measurement is performed in order to obtain the Raman spectrum of a sealing material with the inspection apparatus by Raman spectroscopy which characterizes this invention. It is a figure for demonstrating the measurement point for evaluating the grade of deterioration of a sealing material with a simulation module with the test | inspection apparatus of this invention. It is a characteristic view at the time of performing degradation position evaluation by Raman spectroscopy at each measurement point of a simulation module by the device of the present invention. Explanatory drawing of the evaluation method of deterioration of a sealing material.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
<1> Configuration of Solar Cell Module (Measurement Object) First, the solar cell module 10 as an inspection target handled by the inspection apparatus of the present embodiment will be described. Here, FIG. 1 is a diagram showing the structure of a solar cell module 10 as an inspection object, where (a) shows a plan view and (b) shows a laminated structure.

  As shown in the plan view of FIG. 1A, a plurality of rectangular solar cells 18 are connected in series by lead wires 19 to form a string 15. And what connected the string 15 by the multi-row lead wire 19 and connected the electrodes 16 and 17 to both ends becomes the solar cell module 10 as a test object.

The solar cell panel 10 is molded as follows.
First, as shown in FIG. 1 (b), a sealing material 13 made of a sealing resin is placed on a cover glass 11 as a transparent protective layer disposed on the lower side, and a plurality of strings connected in series thereon. 15 is placed, a sealing material 14 is disposed thereon, and finally a back material 12 made of an opaque material is placed thereon. As the sealing materials 13 and 14, EVA resin (ethylene vinyl acetate) is used. Thereafter, the constituent members are laminated as described above, and pressure is applied under a vacuum heating condition by a laminating apparatus or the like to cause the EVA resin to undergo a cross-linking reaction to perform lamination.

  The solar cell to be inspected according to the present invention is not limited to the solar cell module 10 described above, but only one solar cell 18 or a string 15 in which a plurality of solar cells 18 are linearly connected. Also included. Moreover, it can be set as the inspection object in any state before and after the lamination process.

FIG. 2 is a plan view of one solar battery cell 18 as viewed from the light receiving surface.
In the solar battery cell 18, a bus bar 18 a which is an electrode for taking out electricity is printed on the surface of a thin plate-like silicon semiconductor. In addition, thin conductors called fingers 18b are printed on the surface of the silicon semiconductor in a direction perpendicular to the bus bar in order to efficiently collect current in the bus bar.

  In the Example of this invention, the photovoltaic cell 18 generally called the polycrystalline type of silicon shown in FIG. 2 is illustrated as a test object. Of course, the inspection apparatus and the inspection method according to the present invention are not limited to the polycrystalline type, but also include a thin film type solar cell in which a single crystal type or silicon amorphous type thin film power generation element is electrically connected as a solar cell. .

<2> Description of Inspection Device of the Present Invention Next, the entire configuration of the solar cell module inspection device according to the present invention will be described. Here, FIG. 3 is a figure which shows the schematic structure of the whole test | inspection apparatus of the solar cell module which concerns on this invention.
The solar cell inspection device 100 of the present invention shown in FIG. 3 includes an inspection device main body 20, a moving device 30, and an overall control unit 50.

  The inspection apparatus main body 20 is an inspection apparatus main body using Raman spectroscopy for detecting the degree of deterioration of the sealing material in the solar cell module that characterizes the present invention. The inspection apparatus main body 20 includes an objective lens 21 as a light projecting unit, an imaging lens 22, a slit 23, a spectroscopic unit 24, a spectral analysis unit 25, and the like.

  The spectrum analysis means 25 takes in the spectrum obtained by the spectroscopic means 24 by a program executed by the control section of the personal computer by a personal computer or the like in the overall control section 50 (not shown) and stores it in the memory. The personal computer has a reference data file, which stores standard spectrum diagrams for various substances such as silicon, cover glass, sealing materials, and bus bars. The substance is identified by comparing with the spectrum diagram.

  The control unit 50 is a part that controls the operation of the inspection apparatus body 20. This includes a personal computer as described above, the size of the solar cell module, the size of the power generation portion 70 of the solar cell module (the inner portion of the two-dot chain line in FIG. 1), the thickness size of the solar cell module, and the thickness of the cover glass 11. The dimension information and the position information (x, y coordinates) of the measurement point are input. In addition, an approximate z coordinate in the position information (x, y coordinates) of the measurement point to be measured is determined by a program installed in the overall control unit 50. Furthermore, the moving apparatus 30 is provided and the laser beam irradiation part in the test | inspection apparatus main body 20 is moved to each measurement point. And the correction value of the z coordinate of a measurement point is calculated | required from the measurement result of the test | inspection apparatus main body 20, and the focus position of the objective lens 21 is adjusted to the corrected height (z coordinate).

<3> Outline of Inspection by Raman Spectroscopy An inspection method by the inspection apparatus body 20 will be described with reference to FIG.
The objective lens 21 as a light projecting unit irradiates the solar cell module 10 as an inspection target with laser light having a visible light wavelength from a laser light source (not shown). The laser light passes through the cover glass 11 and the sealing material 13 as a transparent protective layer and focuses on the surface of the back surface material 12, and Raman scattered light is generated from the focal position. Raman scattered light is scattered light having a frequency different from that of the irradiated laser light and having a frequency unique to the substance.

  The Raman scattered light diverges not only from the focal position but also from the front and back of the focal point on the optical axis, but only the scattered light radiated from the focal point passes through the slit by the action of the imaging lens 22 and the slit 23. An image is formed on the spectroscopic means 24. The spectroscopic means 24 is provided with a diffraction grating and an image pickup device such as a CCD, and a spectrum of Raman scattered light can be obtained.

The spectrum obtained by the spectroscopic means 24 is inputted to the spectrum analyzing means 25 and compared with the spectra of various substances registered in advance here, the substance at the focal position can be identified. For example, the crystalline silicon is 520 cm ^-1 in the solar cell, also an amorphous silicon thin film has a peak at 470 cm ^-1. The spectrum of the sealing material applied in the present invention will be described later in <4>.

  The inspection apparatus main body 20 is movable in three axial directions of x, y, and z axes. The moving device 30 can move to any position of the solar cell module 10 by moving along the x and y axes. The z-axis moves toward and away from the solar cell module 10 by movement along the optical axis of the objective lens 21. The cover glass 11 and the sealing material 13 of the solar cell module 10 are transparent. Therefore, if the focal position of the objective lens 21 is between the upper surface of the cover glass 11 and the surface of the back material 12, the Raman scattered light at the focal position can be obtained regardless of where the focal position is.

The laser beam is focused on the surface of the sealing material 13 as follows, for example.
First, the inspection apparatus main body 20 is moved on the z-axis to a position considered to be the surface of the sealing material 13. When laser light is irradiated at that position, Raman reflected light from the focal point passes through the slit 23 and forms an image on the spectroscopic means 24. The spectrum of the spectroscopic means 24 is identified by comparing the spectrum of various substances with the spectrum analyzing means 25 in advance. As a result, if it becomes clear that the substance at the focal position is, for example, the cover glass 11 as a solar cell module, the inspection apparatus main body 20 is moved downward in the figure on the z-axis to do the same. Then, the movement in the z-axis direction is repeated until the sealing materials 13 and 14 are detected next. Except for the power generation portion 70 of the solar cell module, the sealing material 13 and the sealing material 14 are melted and solidified by lamination and integrated. In this way, adjustment can be made so that the focal point of the objective lens 21 comes to the surface of the sealing material. In the embodiment of the present invention, the objective lens 21 is adjusted so that the focal point of the objective lens 21 comes to the surface of the sealing material by moving the objective lens 21 downward in the drawing by submicron to several hundred microns.

<4> Inspection Method According to the Present Invention An evaluation method of the degree of deterioration of the sealing material in the solar cell module will be described using the inspection apparatus 100 according to the present invention. In this embodiment, the case where the solar cell module 10 having the configuration shown in FIG. 1 is used as an object to be measured will be described as an example.

  The inspection apparatus main body 20 described in FIG. 4 inspects a plurality of locations of the sealing materials 13 and 14 covering the solar cells 18 inside the solar cell module 10 as measurement points. Each of these measurement points is specified at the time of inspection using positioning means in the three-axis directions of x, y, and z.

  According to the present invention, each of the measurement points is irradiated with laser light from the objective lens 21 that is a light projecting unit of the inspection apparatus main body 20 by Raman spectroscopy, and the Raman scattered light scattered at the measurement point is spectroscopic unit. The state of the sealing materials 13 and 14 at each measurement point can be analyzed by the spectrum analyzing means 25 by performing the spectrum at 24 and obtaining the spectrum.

FIG. 5 shows an example of the analysis result of the sealing material by such Raman spectroscopy. By performing the probe Raman measurement to obtain the Raman spectrum of the sealing material (EVA), for example, a characteristic having a methylene group peak Thus, measurement through the glass of the inner sealing materials 13 and 14 from the outside of the solar cell panel 10 becomes possible. As shown in FIG. 5, the Raman spectrum of the sealing material has a peak at 2847 cm ⁻¹ . This peak is a peak of a methylene group.

A method for evaluating the degree of deterioration of the sealing material of the present invention will be described. As shown in FIG. 6, a solar cell module 10 </ b> A having a configuration of FIG. 1 having a configuration of FIG. 1 was used to simulate a single solar cell (hereinafter referred to as a “simulation module”). In order to promote the deterioration of the simulated solar cell module 10A, it was treated for 168 hours in an environment of a temperature of 130 ° C. and a humidity of 100% and 2 atmospheres. Thereafter, deterioration evaluation was performed on the measurement points (1) to (5) in FIG. The measurement points (1) to (5) are the same as the measurement points in Table 1 described later.
First, the deterioration behavior of the sealing material is generally ester decomposition and carbonyl modification. That is, deterioration occurs due to a decrease in ester groups inside the sealing material and an increase in ketone (carbonyl) groups.

  As a result of IR measurement of the pseudo module 10A, a decrease in ester and an increase in carbonyl were observed. However, in this method, it was necessary to perform analysis and evaluation by IR (infrared spectroscopy) spectrum by sampling the sealing material by destroying the module. In this case, measurement cannot be performed at the pinpoint of the module, and time and labor are consumed for sampling.

  On the other hand, the characteristics of the Raman spectrum were measured through the glass for the pseudo module 10A subjected to the deterioration promotion treatment. Measurement points (1) to (3) are measurement points of the sealing material 13 on the solar battery cell 18, and measurement points (4) to (5) are sealing materials between the cover glass 11 and the back surface material 12. 13 and 14 measurement points. That is, among these measurement points (1) to (5), particularly, the measurement points (3) to (5) are positions corresponding to the sealing materials 13 and 14 in the peripheral portion of the solar battery module 10. is there. In a general solar cell module as shown in FIG. 1, deterioration is a problem. Raman spectra were analyzed and compared at these measurement points (1) to (5).

  FIG. 7 shows the spectrum of Raman spectroscopy at each measurement point after the simulated solar cell module 10A shown in FIG. 6 is immersed in high-temperature water for a predetermined time as described above. The following can be seen by comparison with the spectra of measurement points 1 to 5.

  As the measurement points (1) to (5) move from the center of the pseudo module 10A toward the periphery, the spectrum has a rising baseline (portion indicated as the baseline in FIG. 8). This phenomenon is due to an increase in the component that emits fluorescence when irradiated with laser light, and is because the amount of ketone groups increases in the peripheral portion where deterioration is severe.

  Therefore, for example, when there is a defect in the seal at the periphery of the sealing material of the solar cell module 10, after placing the module for a predetermined time in a high-temperature and high-humidity atmosphere, measuring from the edge side of the module to the center, Deterioration can be confirmed. Moreover, when the sealing material of a solar cell module receives an extreme heat history by the laminating process by the laminating apparatus, the above-described deterioration can be confirmed also in the central portion.

The degree of deterioration after the sealing material in the solar cell module manufactured as described above is installed outdoors can be evaluated as follows. The evaluation method will be described with reference to FIG.
That is, using a Raman spectrometer, the spectral intensity of the methylene group (2847 cm ⁻¹ ) serving as a reference for the sealing materials 13 and 14 is assumed to be intensity A, and the baseline intensity is assumed to be intensity B (2200 cm ^{−1 in} FIG. 8). Then, the degradation degree D is defined as follows.
Deterioration degree D = B / A × 100
The degree of deterioration at the target location (measurement point) is determined and evaluated. The base line can be arbitrarily selected from the range of 1800 to 2700 cm ⁻¹ .

表１より、モジュールの周辺部から水の浸入により封止材が劣化していることが分かる。 Table 1 shows the result of determining the degree of deterioration D by performing Raman measurement on the position from the center to the peripheral part of the pseudo module 10A and using the distance from the center and the intensity at 2200 cm ⁻¹ as the baseline. .

From Table 1, it can be seen that the sealing material has deteriorated due to the ingress of water from the periphery of the module.

  According to such an inspection apparatus 100 and an inspection method of the present invention, at the time of sampling inspection of a solar cell module after manufacture, or when performing a life evaluation inspection of an existing solar cell module that is actually installed and used in the field. Thus, it is not necessary to destroy the solar cell panel as in the prior art, and it is possible to obtain an appropriate and reliable inspection result and perform life evaluation only by non-destructive inspection, and its usefulness is great.

  In addition, this invention is not limited to the structure demonstrated in the Example mentioned above, It cannot be overemphasized that the shape of each part which comprises the inspection apparatus by the Raman spectroscopy of a solar cell module, a structure, etc. can be deform | transformed and changed suitably. .

10 Solar cell module 10A Pseudo module 11 Cover glass (transparent protective layer)
DESCRIPTION OF SYMBOLS 12 Back material 13, 14 Sealing material 15 String 18 Solar cell 20 Inspection apparatus main body 21 Objective lens 22 Imaging lens 23 Slit 24 Spectroscopic means 25 Spectral analysis means 30 Moving device 50 Overall control part 70 Electric power generation part of solar cell module 100 Inspection apparatus of the present invention

Claims (4)

An inspection apparatus for determining the degree of deterioration of a sealing material in a solar cell module having one or more solar cells,
Projection means for irradiating a plurality of measurement points in the solar cell module to be inspected with laser light;
A spectroscopic means for obtaining a spectrum by dispersing Raman scattered light scattered from the inspection object at the measurement point;
From the spectrum of Raman scattered light obtained by the spectroscopic means, comprising spectral analysis means for analyzing the state of the solar cell at the measurement point,
At least one of the measurement points is set so as to be positioned in a peripheral portion of the sealing material in the solar cell module.   The said measuring point is specified using the positioning means in the triaxial direction of x, y, and z, The inspection apparatus of the said sealing material of Claim 1 characterized by the above-mentioned.   The solar cell module is a solar cell module having a laminate structure in which a plurality of solar cells are electrically connected and arranged in a plane, and the front and back are sandwiched between a transparent protective layer and a back sheet via a sealing material. The said sealing material inspection apparatus of Claim 1 or Claim 2 characterized by these. An inspection method for determining the degree of deterioration of a sealing material in a solar cell module having one or more solar cells,
Identifying a plurality of measurement points positioned in the three-axis directions of x, y, and z on the solar cell module to be inspected;
Irradiating a laser beam with each measuring point focused;
Spectroscopically obtaining Raman scattered light scattered from the inspection object at the measurement point;
Detecting the state of the sealing material in the solar cell module at each measurement point;
Analyzing the degree of deterioration of the sealing material, and performing a life evaluation of the solar cell module, and a method for inspecting the sealing material in the solar cell module.

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