JP2012042440A - Flaw detection inspection method of flexible solar battery, and inspection equipment for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new inspection method and inspection equipment by which a degree of a damage by a mechanical load to affect electric performance of a flexible solar battery is understood in flexibilization and configuration optimization of the flexible solar battery.SOLUTION: An acoustic emission (AE) sensor is arranged at the center part of the lengthwise direction of a flexible solar battery cell, the flexible solar battery cell is installed in a tensile testing machine to be pulled in the lengthwise direction, an acoustic emission (AE) generated resulting from the damage generated in pulling is detected by the AE sensor to be converted into the acoustic emission (AE) signal. Then, a change of electric characteristics based on the AE signal is recognized to inspect the change of electric characteristics resulting from the damage of the flexible solar battery.

Description

  The present invention relates to a damage inspection method for a flexible solar cell and an inspection apparatus therefor.

  Currently, with the background of environmental problems, development of flexible solar cells using film-like substrates such as organic thin films and metal foils that have advantages such as light weight, flexibility, and resource saving is underway. Applications for folding portable power supplies, emergency tent power supplies, satellite power supplies, etc. are expanding.

In order to evaluate the flexibility of the flexible solar cell, it is important to identify the mode and generation process of the damage that causes the performance deterioration. In Non-Patent Document 1, a flexible solar cell having a small area of about 1 cm ² is manufactured and a bending strain is applied to the test piece, whereby the bending strain with respect to the electrical performance of the flexible solar cell is reduced. We are investigating the impact. However, in this method, the generation process and identification of damage modes that cause performance degradation are not sufficiently performed.

  On the other hand, in order to make flexible solar cells flexible and to optimize their structures, it is essential to understand the damage process caused by mechanical loads and the effect of these damages on the electrical performance.

R. Jones, T. Jhonson, W. Jordan, S. Wagner, J. Yang and S. Guha, Proc. 29th IEEE photovoltaic Specialists Conference, pp. 1214-1217 (2002)

  The present invention provides a novel inspection method and inspection apparatus capable of understanding the degree of damage due to a mechanical load that affects the electrical performance in flexible and structural optimization of a flexible solar cell. With the goal.

In order to achieve the above object, the present invention is a method for inspecting a flexible solar cell for damage,
Preparing the flexible solar cell or cells of the flexible solar cell;
Disposing an acoustic emission (AE) sensor at a central portion in a length direction of the flexible solar cell or the cell of the flexible solar cell;
The flexible solar cell or the cell of the flexible solar cell is installed in a tensile tester and pulled in the length direction, and acoustic emission (AE) generated due to damage caused at that time is detected by the AE sensor. Converting to an acoustic emission (AE) signal;
It is related with the damage inspection method of a flexible solar cell characterized by comprising.

Further, the present invention is an apparatus for inspecting damage to a flexible solar cell,
A tensile tester for pulling the flexible solar cell or the cell of the flexible solar cell in a length direction to cause damage to the test piece;
The flexible solar cell or the flexible solar cell for detecting acoustic emission (AE) generated due to the damage of the flexible solar cell or the cell of the flexible solar cell and converting it into an acoustic emission (AE) signal An acoustic emission (AE) sensor arranged in the center of the solar cell in the length direction;
It is related with the damage inspection apparatus of a flexible solar cell characterized by comprising.

  According to the present invention, the flexible solar cell or the cell of the flexible solar cell is attached to the tensile testing machine. Accordingly, the tensile tester can apply a large tensile strain to the flexible solar cell or the flexible solar cell, thereby damaging the flexible solar cell or the flexible solar cell. become able to. On the other hand, an elastic wave, that is, acoustic emission (AE) is generated from the damage generated as described above.

  On the other hand, since an acoustic emission (AE) sensor is disposed at the center of the flexible solar cell or the flexible solar cell, the above AE is detected by the AE sensor, and an acoustic emission (AE) signal is obtained. Is converted to Therefore, by examining this AE signal, it is possible to roughly know the magnitude and degree of damage that has occurred in the test piece.

  Further, at the same time as examining the damage of the test piece as described above, the change in the electrical characteristics of the test piece is examined by, for example, irradiating the test piece with lamp light, for example, Xe lamp light. Then, as described above, since the test piece is damaged, the electrical characteristics change as the damage occurs. Therefore, it becomes possible to know a change in electrical characteristics based on damage to the test piece.

  In an example of the present invention, a pair of additional AE sensors can be arranged at both end positions of the test piece corresponding to the fixing member of the tensile tester. Such an additional AE sensor functions so as to detect AE generated due to damage caused in the test piece, similarly to the AE sensor arranged in the center of the test piece described above. It is also possible to detect the position where the AE generated due to the damage is generated by increasing the number of channels. The generation position is detected by measuring the arrival time difference of the generated AE to each AE sensor and multiplying this by the speed of sound to identify the distance from each AE sensor to the AE generation position. It can be done by using it.

  However, it functions as a so-called guard sensor, detects AE based on friction generated between the flexible solar cell or the cell of the flexible solar cell and the fixing member of the tensile tester, and removes the AE signal based on the AE signal as a noise signal. It can also be made to function. In addition, the detection of AE generated in the fixing member can be performed based on the above-described detection method of the generation position of AE.

  Specifically, when friction occurs between the flexible solar cell or the cell of the flexible solar cell and the fixing member of the tensile tester, the AE associated therewith is immediately detected by the AE sensor provided at the location. The AE sensor arranged at the center of the piece is detected with a delay. Therefore, AE generated with the friction can be easily identified and easily removed by signal processing. As a result, only the AE based on the damage generated on the test piece can be accurately detected. For this reason, it becomes possible to accurately know the change in electrical characteristics based on the damage of the test piece.

  Japanese Patent Application Laid-Open No. 2002-3431992 discloses a method for inspecting internal cracks in a solar cell using the AE method. However, in this method, a solar cell in which an internal defect already exists is curved to reveal the internal defect, AE generated at that time is detected, and whether or not there is an internal crack in the solar cell. It is only an inspection. Moreover, in the said gazette, it is aimed at the photovoltaic cell and is not intended for the flexible solar cell as in the present invention.

  On the other hand, as described above, the present invention intentionally damages the flexible solar cell or the cells of the flexible solar cell, and inspects how much the electrical characteristics of the flexible solar cell change due to the damage. In other words, it examines the mechanical load and the degree of damage that accompany it in the flexible and structural optimization of the flexible solar cell, and obtains guidelines for designing the flexible solar cell.

  Therefore, the present invention and the technique described in the above publication are completely different from each other in configuration and operation effect.

  In the present invention, the flexible solar cell is of a kind that cannot be divided into cells, and when the flexible solar cell does not exceed the size of the range allowed by the tensile tester, the flexible solar cell itself is When the flexible solar cell can be divided into cells and the flexible solar cell exceeds the size allowed by the tensile tester, the flexible solar cell can be used. The cell is cut into cells, and the obtained flexible solar battery cell is subjected to a test.

  The flexible solar cell in the present invention may be any type of flexible solar cell such as a dye-sensitized organic solar cell in addition to a solar cell using general-purpose amorphous silicon.

  As described above, according to the present invention, in the flexible and structural optimization of a flexible solar cell, a novel inspection capable of understanding the degree of damage due to a mechanical load affecting the electrical performance. A method and inspection apparatus can be provided.

It is a top view which shows an example of the flexible photovoltaic cell used by this invention. It is a schematic block diagram which shows the unit structure of the flexible photovoltaic cell shown in FIG. It is a figure for demonstrating the schematic structure of an example in the test | inspection apparatus of this invention, and the test | inspection method using the same. It is a graph which shows the relationship between the open circuit voltage (Voc) in an Example, and an acoustic emission signal (AE signal).

  Hereinafter, details of the present invention and other features and advantages will be described based on embodiments.

  FIG. 1 is a plan view showing an example of a flexible solar cell used in the present invention, and FIG. 2 is a schematic configuration diagram showing a unit structure of the flexible solar cell shown in FIG.

  The flexible solar cell 10 shown in FIG. 1 has, for example, a length of about 112 mm and a width of about 11 mm. As shown in FIG. Back electrode layer 12 having a thickness of about 0.2 μm, amorphous Si light absorption layer 13 having a pin junction having a thickness of about 1 μm, transparent electrode layer 14 having a thickness of about 0.1 μm, and a strip shape having a thickness of about 15 μm and a width of 0.5 mm The grid electrode 15 is formed. Further, protective films 16 and 17 made of a PET film having a thickness of 125 μm, for example, are provided on the substrate 11 side, the transparent electrode 14 and the grid electrode 15 side.

  After preparing the flexible solar battery cell 10 as described above, the inspection method of the present invention is performed by using the cell 10.

  In addition, in this embodiment, although the flexible solar cell 10 is used, it is a kind which a flexible solar cell cannot divide | segment into a cell, and the flexible solar cell exceeds the magnitude | size of the range which a tensile tester accept | permits. If this is not the case, the flexible solar cell itself is directly attached to the tensile tester for testing.

  FIG. 3 is a diagram for explaining a schematic configuration of an inspection apparatus of the present invention and an inspection method using the same.

  The inspection apparatus 30 shown in FIG. 3 has a tensile tester 31, and the ends of the flexible solar cells 10 are sandwiched between a pair of chucks 32 that are fixing members provided at both ends of the tensile tester 31. The flexible solar battery cell 10 is installed and fixed to the tensile testing machine 31 in the length direction. The tensile testing machine 31 is configured such that an external load acts on the lower chuck 32 to pull the test piece 20 downward, and the upper chuck 32 is fixed and the load cell 33 is connected. Configured.

  In addition, an acoustic emission (AE) sensor 35 is attached to the center of the flexible solar cell 10, and an additional pair of AE sensors 36 are attached to both ends sandwiched by the chuck 32 of the flexible solar cell 10. It has been. These AE sensors 35 and 36 are equipped with amplifiers 41 to 43, respectively, which amplify and analyze acoustic emission (AE) signals converted from acoustic emission (AE) detected by the AE sensors 35 and 36. The data is transmitted to a device 45 and a personal computer (PC) 46 for analysis as shown below.

  Furthermore, an Xe lamp 48 is disposed at a position about 100 mm away from the center of the flexible solar cell 10, and light is irradiated from the Xe lamp 48 at the same time as the tensile tester 31 pulls the test piece 20 downward. It is comprised so that the electrical property as a solar cell of the test piece 20 can be investigated.

  In the inspection apparatus 30 shown in FIG. 3, the AE sensor 35 attached to the central portion of the flexible solar battery cell 10 and the AE sensors 36 attached to both ends make a multichannel and cracks due to strain generated in the flexible solar battery cell 10. However, the AE sensor 36 functions as a so-called guard sensor, and the friction generated between the flexible solar cell 10 and the chuck 32 of the tensile tester 31 can be detected. It is also possible to function to detect the AE based on it and remove the AE signal based on it as a noise signal.

  In the latter case, only the AE (signal) due to the inherent damage occurring in the flexible solar battery cell 10 can be detected, so the reliability of the correlation between the damage and the AE (signal) is increased. To do.

  In order to make the AE sensor 36 function as a noise removal sensor, it is performed as follows. When carrying out the inspection method of the present invention, the flexible solar battery cell 10 is pulled downward by the tensile tester 31 to cause damage such as cracking due to strain on the flexible solar battery cell 10. At this time, friction is generated between the flexible solar battery cell 10 and the chuck 32 of the tensile testing machine 31, and AE is generated accordingly. Although this AE is immediately detected by the AE sensor 36 located in the vicinity, the AE is detected with a delay by the AE sensor 35 disposed in the central portion of the flexible solar battery cell 10.

  Therefore, the AE generated with the friction can be easily identified, and can be easily removed by signal processing in the analyzer 45 and the PC 46. As a result, only the AE based on the damage generated in the flexible solar battery cell 10 can be accurately detected.

  The same applies to the case where the AE sensor is multi-channeled and the occurrence position of the AE generated due to the damage is detected, and the arrival time difference of the generated AE to the AE sensors 35 and 36 is measured. Since the distance from the AE sensors 35 and 36 to the generation position of the AE can be identified by multiplying the sound speed by the AE, the generation position of the AE can be identified by using this.

  When attaching the AE sensor, in order to suppress damage such as cracks due to strain caused by tension by the tensile testing machine 31 and the influence on AE measurement due to this, further testing of the AE sensor due to tensile deformation. In order to suppress deviation from the piece, it is preferable to use an elastic adhesive.

Next, actual inspection results based on the above-described inspection method and inspection apparatus will be shown.
The flexible solar cell 10 shown in FIG. 1 was installed and fixed on the tensile tester 31 shown in FIG. Thereafter, the tensile tester 31 is pulled downward at a speed of 0.1 mm / min, and AE caused by damage such as cracks generated during this time is detected by the AE sensor 35 and converted into an AE signal, and the analyzer 45 and PC 46. Further, the AE caused by the friction generated between the flexible solar cell 10 and the chuck 32 is detected by the AE sensor 36 and converted into the AE signal, and the AE signal is transmitted to the analyzer 45 and the PC 46 as the AE signal. A high-accuracy AE signal was obtained.

As the AE sensors 35 and 36, broadband AE sensors (manufactured by NF, AE-900M) were used. The flexible solar cell 10 was irradiated with light having a radiation intensity of 1000 ± 50 (W / m ² ), and the open circuit voltage (Voc) was examined.

  FIG. 4 is a graph showing the relationship between the open circuit voltage (Voc) and the AE signal. The horizontal axis represents time.

  As can be seen from FIG. 4, at the beginning of the test, the open circuit voltage (Voc) slightly increases with time, but rapidly deteriorates with the appearance of the AE signal. In other words, it can be seen that damage such as cracking due to strain appears in the flexible solar battery cell 10 and the open circuit voltage (Voc) rapidly decreases. Therefore, from FIG. 4, the correlation between the damage caused in the flexible solar cell 10 and the open circuit voltage (Voc) is confirmed, and the damage of the flexible solar cell 10 has a great influence on the change in the change in its electrical characteristics. It was confirmed that

  In addition, from the above-mentioned result, it is naturally expected that other electrical characteristics other than the open circuit voltage (Voc) are also greatly influenced by the AE signal from the flexible solar battery cell 10, that is, damage. is there. Furthermore, since the AE signal is detected before the open circuit voltage is lowered, it can be seen that the AE measurement can capture damage with higher sensitivity than the open circuit voltage measurement.

  While the present invention has been described in detail based on the above specific examples, the present invention is not limited to the above specific examples, and various modifications and changes can be made without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 10 Flexible solar cell 11 Board | substrate 12 Back surface electrode layer 13 Amorphous Si light absorption layer 14 Transparent electrode layer 15 Grid electrode 16, 17 Protective film 30 Inspection apparatus 31 Tensile tester 32 Chuck 33 Load cell 35, 36 Acoustic emission (AE) sensor 41 , 42, 43 Amplifier 45 Analyzer 46 Personal computer 48 Xe lamp

Claims (6)

A method for inspecting flexible solar cells for damage,
Preparing the flexible solar cell or cells of the flexible solar cell;
Disposing an acoustic emission (AE) sensor at a central portion in a length direction of the flexible solar cell or the cell of the flexible solar cell;
The flexible solar cell or the cell of the flexible solar cell is installed in a tensile tester and pulled in the length direction, and acoustic emission (AE) generated due to damage caused at that time is detected by the AE sensor. Converting to an acoustic emission (AE) signal;
A method for inspecting damage to a flexible solar cell, comprising:   The damage inspection of the flexible solar cell according to claim 1, further comprising a step of arranging a pair of additional AE sensors at both end positions of the test piece corresponding to fixing members of the tensile tester. Method.   A step of detecting an additional AE based on friction generated between the test piece and the fixing member by the pair of additional AE sensors, and removing the additional AE as a noise signal; The method for inspecting damage to a flexible solar cell according to claim 2. An apparatus for inspecting damage to a flexible solar cell,
A tensile tester for pulling the flexible solar cell or the cell of the flexible solar cell in a length direction to cause damage to the test piece;
The flexible solar cell or the flexible solar cell for detecting acoustic emission (AE) caused by the damage of the flexible solar cell or the cell of the flexible solar cell and converting it into an acoustic emission (AE) signal An acoustic emission (AE) sensor arranged in the center of the solar cell in the length direction;
A flexible solar cell damage inspection apparatus comprising:   5. The flexible solar cell damage inspection apparatus according to claim 4, further comprising a pair of additional AE sensors at both end positions of the test piece corresponding to a fixing member of the tensile tester.   The pair of additional AE sensors are configured to detect an additional AE based on friction generated between the test piece and the fixing member and remove the additional AE as a noise signal. The damage inspection apparatus for a flexible solar cell according to claim 5.

Images