JP4765052B2 - Integrated thin film solar cell evaluation apparatus and evaluation method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an evaluation apparatus and an evaluation method for an integrated thin film solar cell, and in particular, an evaluation of an integrated thin film solar cell capable of measuring local characteristics of a light receiving surface of a solar cell and detecting a local defect. The present invention relates to an apparatus and an evaluation method.
[0002]
[Prior art]
FIG. 8A is a perspective view of an integrated thin film solar cell, and FIG. 8B is a cross-sectional view of the AA line. In FIG. 8, 101 is a substrate, 102 is a first electrode, 103 is a semiconductor layer made of a-Si, 104 is a second electrode, and 105 and 106 are a pair of output terminals. There are two types of integrated thin-film solar cells: front light irradiation type and back surface (substrate side) light irradiation type. In the former case, a transparent conductive film (TCO) is used for the second electrode, and in the latter case A transparent conductive film is used for the first electrode, and a transparent substrate such as glass is used for the substrate.
[0003]
As shown in FIG. 8, each cell of the integrated thin film solar cell has a first electrode 102, a semiconductor layer 103, and a second electrode 104, and is formed in a strip shape. Each cell is connected in series via the first electrode 102 and the second electrode 104, and the entire output is taken out via output terminals 105 and 106 provided at both ends of the series connection body.
The test and measurement of the solar cell thus formed has been performed by irradiating the entire surface with light and measuring the voltage-current characteristics using the output terminals 105 and 106. Based on the result, the maximum output (Pmax) is obtained, and the curve factor calculated from Pmax / Isc · Voc (Isc is the short-circuit current, Voc is the open-circuit voltage): FF value, etc. (for example, Patent Document 1) reference).
[0004]
[Patent Document 1]
JP 2002-270877 A (page 3-7, FIG. 6-8)
[0005]
[Problems to be solved by the invention]
Actually produced integrated thin-film solar cells vary in characteristics due to various factors in the process. In recent years, thin-film integrated solar cells have been increased in the area of the m ² size class, but due to the increase in area, uniform film formation and maintenance thereof are difficult, non-uniform portions of film thickness and composition, pinholes, etc. Tends to cause performance degradation and instability over time. Conventionally, the entire surface of the solar cell light-receiving surface was irradiated with light and the overall characteristics were measured, so it was difficult to determine where the characteristic variation and defect factors existed on the substrate. And even if there is a large variation in characteristics in the plane, the variation will be averaged, so the variation will not be obvious. Despite being presumed to be fast, it has been treated as a good product. It has also been difficult to pursue which of the semiconductor layers has a cause of variation or a defect. For this reason, it is difficult to identify the location of the film on the substrate, regardless of whether the product has variations or defects, and it takes a long time to deal with defects and is effective in reducing variations. It was difficult to find a proper means.
An object of the present invention is to solve the above-mentioned problems of the prior art, and its purpose is to be able to detect internal variations and local defects and to identify positions with large variations and defect occurrence positions. As a result, products with large internal variations and products with local defects will not be shipped, and it will be possible to take quick and accurate countermeasures to manufacture products with little variation. It is something to try.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, a mounting table for mounting an integrated thin film solar cell module in which strip-shaped cells are connected in series, and irradiation on the integrated thin film solar cell module , and long line-shaped light sources in the direction of the series connection of cells, one or both of the light source or the mounting table, and means before moving stepwise in a direction perpendicular to the longitudinal direction of the light source, the integrated There is provided an integrated thin film solar cell module evaluation apparatus including a measuring device that automatically measures current-voltage characteristics during light irradiation of the thin film solar cell module in conjunction with the step-like movement.
Preferably, either one or both of the light source and the mounting table can be moved stepwise in a direction perpendicular to the length direction of the light source, whereby the entire solar cell light-receiving surface can be moved. It is configured so that the area can be measured.
[0007]
In order to achieve the above object, according to the present invention, the integrated thin-film solar cell module in which strip-shaped cells are connected in series is irradiated with long line-shaped light in the series connection direction of the cells, moving the line-shaped light receiving portion stepwise current during light irradiation of the integrated thin-film solar cell module - wherein the intends automatically line measurement of the voltage characteristics in conjunction with the movement of the step-like An evaluation method for an integrated thin film solar cell module is provided.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a perspective view showing a first embodiment of the present invention, and FIG. 2 is a block diagram of its control unit. As shown in FIG. 1, a stage 2 on which an integrated thin film solar cell 5 is placed is installed in a dark box 1 that is a light-shielded container, and the integrated thin film solar cell is placed on the stage 2. A line structure light source 4 capable of irradiating the surface 5 in a line is movably installed. The line structure light source 4 is configured to be moved in a step shape by the step driving unit 3, so that the entire light receiving surface of the integrated thin film solar cell 5 can be irradiated.
[0009]
The longitudinal direction of the line structure light source 4 is the series connection direction of the cells of the integrated thin film solar cell (the left-right direction in FIG. 8). The light source of the line structure light source 4 is a lamp or LED. A halogen lamp or a xenon lamp can be used as the lamp. A rod-shaped lamp can be used as the lamp, and a plurality of lamps may be mounted in the line structure light source 4. Particularly preferred as the lamp is a halogen lamp.
When an LED is used as a light source, a plurality of monochromatic or white LEDs within a wavelength range of 0.3 to 1.5 μm are linearly arranged. A plurality of LEDs having different emission colors may be prepared, and the LEDs having different colors may be switched to emit light. In this case, the LEDs may be arranged in different columns for different emission colors, and the LED columns of different colors may be made to emit light by switching. In integrated thin film solar cells, semiconductor layers having different bandwidths are often stacked. In this case, by irradiating illumination light of different emission colors and performing characteristic measurement, it becomes easy to specify which semiconductor layer has the cause of the defect.
[0010]
The length of the line light is set between the output terminals of the light receiving surface of the solar cell, and the width of the line light is set to a width of 3 to 50 mm. The width of the line light is determined in relation to the step width sent by the line structure light source 4.
The line structure light source 4 is equipped with a light diffusing plate for making the light intensity uniform. Moreover, a filter is mounted as needed. For example, when a white LED is used as a light source, the light emission color of the white LED is higher in light intensity on the blue side than normal white light, so it is desirable to correct the emission spectrum of the white LED by using a filter.
The line structure light source 4 can emit light continuously throughout the measurement of the entire surface of the thin-film solar cell, but may emit light only during characteristic measurement.
[0011]
The line structure light source 4 is sent in steps from the end of the light receiving surface of the solar cell by the step driving unit 3. The desired step width is 3 to 50 mm. A desirable number of steps for one solar cell is 10 to 100. If the number of steps is large, the accuracy is improved, but the measurement time is prolonged. Therefore, the number of steps is determined in consideration of the balance between accuracy and productivity. When the measurement is completed for one solar cell, the line structure light source 4 is returned to the initial position by the step driving unit 3.
A series of operations such as loading / unloading of the integrated thin-film solar cell, step feeding of the line structure light source, and measurement of characteristics are controlled by the control unit 6. The atmosphere in the dark box 1, that is, the temperature and / or humidity is controlled by the air conditioning unit 7. By providing the air conditioning unit 7, it becomes possible to measure characteristics according to temperature changes or humidity changes.
[0012]
As shown in FIG. 2, the control unit 6 includes a central processing unit 61 as a center, a substrate carry-in / out unit 62, a light source control unit 63, a measurement unit 64, a calculation unit 65, a determination / selection unit 66, and a recording unit. 67 is provided. The substrate carry-in / carry-out unit 62 receives instructions from the central processing unit 61 and controls the carry-in / carry-out and positioning of the solar cell to be measured. The light source control unit 63 includes a light source position control unit 631 and an illumination control unit 632. When a trigger signal is issued from the central processing unit 61, the light source position control unit 631 sends the line structure light source by one step. The illumination control unit 632 controls on / off of the light source according to an instruction from the central processing unit 61. The light source position control unit 631 also controls the return of the initial position of the light source when the measurement is completed for the solar cell to be measured. When the measurement unit 64 receives a signal from the central processing unit 61 that the introduction of the solar cell to be measured has been completed or the one-step movement of the line structure light source has been completed, the IV characteristic for one line of the solar cell to be measured. Measure. When the central processing unit 61 receives a signal indicating that the measurement of the IV characteristic for one line is completed from the measurement unit 64, the central processing unit 61 transmits a trigger signal to the light source control unit 63. The calculation unit 65 receives the measurement data of the measurement unit 64 and calculates the maximum output Pmax and the FF value based on the measurement data. The measurement data of the measurement unit 64 and the calculation result of the calculation unit 65 are transmitted to the determination / selection unit 66 and the recording unit 67. When the determination / selection unit 66 acquires data of the entire surface of the solar cell to be measured, the determination / selection unit 66 determines whether the solar cell to be measured is good or bad, and issues a warning when a defective product is generated. Classifies according to its opto-electrical characteristics. When a warning is issued, feedback is given to the production line.
[0013]
FIG. 3 is a flowchart showing an example of the flow of processing using the integrated thin-film solar cell measuring apparatus according to the present embodiment shown in FIGS. In this example, it is assumed that the line structure light source is always turned on, and the number of step feeds of the line structure light source is N (N + 1 line areas to be measured). In the solar cell processing unit A, in step S11, the solar cell to be measured is sent onto the stage and positioned. In step S12, n = 0 is set. In step S13, the opto-electric characteristic is measured. That is, the current-voltage characteristic of the line-shaped part irradiated with light is measured. In step S14, it is checked whether n is N or not. When it is N, it reaches step S15 and the solar cell to be measured is removed from the stage and carried out of the apparatus. In step S16, the line structure light source is returned to the initial position. If it is determined in step S14 that n = N is not satisfied, the process reaches step S17 to generate a trigger signal, and in step S18, the line structure light source is moved by one step. In step S19, after n = n + 1, the process proceeds to step S13.
[0014]
In the data processing unit B, when the solar cell to be measured is carried in at step S11 of the solar cell processing unit A, m = 0 is set at step S21, and step S13 of the solar cell processing unit A is set at step S22. The measurement data obtained in is taken in. In step S23, the maximum output Pmax is obtained based on the acquired measurement data, and the FF value is calculated. Next, in step S24, it is checked whether m is N. When m is N, the process proceeds to step S25, where the measurement result and calculation result of the solar cell to be measured that has been measured are acquired, and the solar cell is determined and selected. That is, defective products are excluded and non-defective products are classified according to characteristics. If a defective product is generated, feedback is provided to the production line (step S26). If it is determined in step S24 that m is not N, a trigger signal standby state is set. In step S27, when the trigger signal transmitted in step S17 is received, the process proceeds to step S28, and after m = m + 1, the process proceeds to step S22.
[0015]
FIG. 4 is a schematic sectional view showing a second embodiment of the present invention. In this Embodiment, it is comprised so that the stage in which the to-be-measured solar cell is mounted can move. That is, the integrated thin film solar cell 15 is placed and positioned on the movable stage 12 that is stepped. The movable stage 12 is installed on the floor surface of the dark box 11 so as to be movable in steps, and a line structure light source 14 is fixed to the ceiling of the dark box 11. The longitudinal direction of the line structure light source 14 is a direction perpendicular to the paper surface, and the series connection direction of the cells of the integrated thin film solar cell 15 is also this direction.
Also in this embodiment, the same effect as that of the previous embodiment can be obtained by step-moving the movable stage 12 and measuring the electrical characteristics for each step feed.
[0016]
FIG. 5 (a) is a schematic perspective view showing a third embodiment of the present invention, and FIG. 5 (b) is a perspective view of an essential part thereof. In the present embodiment, a line light source array 24A equipped with a plurality of line structure light sources 24 is used. The light irradiation range of the light source array 24A is determined by the length and the number of the line structure light sources 24 so that the entire light receiving area of the integrated thin film solar cell 25 can be covered. That is, the length of the line structure light source 24 is set between the output terminals of the light receiving surface of the solar cell, the width is 3 to 50 mm, and the number is 10 to 100. The light source array 24 </ b> A is moved up and down by the drive unit 23, and is brought into contact with the surface when the integrated thin film solar cell 25 is measured. Each line structure light source 24 of the light source array 24A is supplied with power from a lighting power supply sequential supply circuit 26 and is sequentially turned on.
[0017]
Next, the operation of the apparatus according to the present embodiment will be described. The integrated thin film solar cell 25 that is a wafer to be measured is carried into the dark box 21 by a transfer means (not shown) and positioned at a predetermined position on the stage 22. Next, the line light source array 24 </ b> A is lowered by the drive unit 23, and the surface thereof is brought into contact with the light receiving surface of the integrated thin film solar cell 25. Subsequently, for example, the line structure light source 24 at the right end in FIG. 5B is turned on by the lighting power supply sequential supply circuit 26. Then, measurement is performed on the light irradiation region, that is, the line-shaped region at the left end of the integrated thin-film solar cell 25 shown in FIG. When the measurement for the line-shaped region is completed, the lighting power supply sequential supply circuit 26 turns on the second line structure light source 24 from the right shown in FIG. 5B, and the integrated type shown in FIG. Measurement is performed on the second linear region from the left of the thin-film solar cell 25. Hereinafter, similarly, each line structure light source of the line light source array 24A is sequentially turned on, and the measurement of the line-shaped measurement region of the integrated thin-film solar cell 25 is sequentially performed in conjunction therewith. When the measurement for the entire light receiving region of the integrated thin film solar cell 25 is completed, the line light source array 24A is raised by the drive unit 23, and the integrated thin film solar cell 25 is carried out of the dark box 21 by the transport means (not shown). Is done.
[0018]
【Example】
An integrated thin film solar cell was fabricated in which molybdenum (Mo) was used as a lower electrode on a glass substrate, and a p-type CIGS (CuInGaSe) film, an n-type CdS film, a ZnO film, and an Al-doped ZnO film were sequentially laminated. The light receiving area of this module is 171 mm (cell longitudinal direction) x 308 mm (cell serial connection direction), and the number of cell stages is 42. On one of the modules (a module A), using a line structured light source the size of the opening is a light emitting source rod-shaped halogen lamp 308X3mm ^2, and 57 lines irradiated with 3mm step, the characteristic line by line It was measured. The results obtained for module A are shown in FIG. The same measurement was performed for other modules (referred to as module B). Based on the measurement results for each line, the maximum output Pmax and the fill factor FF were obtained for each line.
FIG. 7 is a graph showing the short circuit current Isc, the open circuit voltage Voc, the maximum output Pmax, and the fill factor FF for each line of the module A and the module B. In FIG. 7, the vertical axis represents the variation width of each characteristic value. When the allowable value of the variation of each characteristic value is set to 10%, the module B becomes an acceptable product, but the module A fails because the variation exceeds 10% at Pmax.
[0019]
When the module A and the module B are measured and evaluated by the conventional method, that is, when the entire surface of the light receiving surface is irradiated with light and the entire characteristics are measured, the in-plane variation is averaged. Similar measurement results are obtained and both are determined to be non-defective. However, if a region with poor characteristics exists locally in the plane, the deterioration proceeds from that region. Therefore, in order to improve stability over time and ensure long-term reliability, local in-plane It is desirable to reject products that have poor parts at the shipping stage. In addition, when products with locally inferior parts are being manufactured, improvement in the manufacturing process is desired, but the conventional method cannot detect the occurrence of defective products, and requests a process improvement method from the manufacturing site. It was impossible. The present invention provides an effective means for finding defective products and providing feedback to production lines.
[0020]
Although preferred embodiments and examples have been described above, the present invention is not limited to these embodiments, and appropriate modifications can be made without departing from the gist of the present invention. For example, in the above-described embodiment, the step movement is either a line structure light source or a stage, but both may be configured to be step-movable.
[0021]
【The invention's effect】
As described above, according to the present invention, an integrated thin film solar cell is irradiated with a line structure light source to measure the opto-electrical characteristics of the line-shaped portion and evaluate its performance. The local characteristics of the battery can be evaluated. Therefore, according to the present invention, it becomes possible to recognize characteristic variations and local defects inside the integrated thin film solar cell, and it has high internal uniformity and does not include local defect elements, that is, deterioration over time occurs. It is possible to supply products with guaranteed quality. At the same time, it becomes possible to provide information feedback to the manufacturing process of variations in characteristics and local defects within the solar cell, and it is possible to provide useful information for process management.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view showing a first embodiment of the present invention.
FIG. 2 is a block diagram showing a configuration of a control unit of the apparatus shown in FIG.
3 is a flowchart showing a processing flow of the apparatus shown in FIG. 1;
FIG. 4 is a schematic cross-sectional view showing a second embodiment of the present invention.
FIG. 5 is a schematic perspective view showing a third embodiment of the present invention.
FIG. 6 is a graph showing measurement results of an example of the present invention.
FIG. 7 is a characteristic curve diagram obtained from the measurement result of FIG.
FIG. 8 is a perspective view and a cross-sectional view of an integrated thin film solar cell.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1, 11, 21 Dark box 2, 22 Stage 3 Step drive part 4, 14, 24 Line structure light source 5, 15, 25 Integrated thin film solar cell 6 Control part 7 Air conditioning part 12 Movable stage 23 Drive part 24A Line light source array 26 Power supply sequential supply circuit for lighting

Claims (13)

A mounting table for mounting the integrated thin film solar cell module in which strip-shaped cells are connected in series, a line-shaped light source that illuminates the integrated thin film solar cell module , and is long in the serial connection direction of the cells, one or both of the light source or the mounting table, and means before moving stepwise in a direction perpendicular to the longitudinal direction of the light source, when the light irradiation of the integrated thin-film solar cell module current - voltage characteristics An integrated thin-film solar cell module evaluation apparatus including a measuring device that automatically performs measurement in conjunction with the step-like movement. 2. The integrated thin film solar cell module evaluation apparatus according to claim 1, wherein the step-like movement is started by a trigger signal. 2. The integrated thin film solar cell according to claim 1, wherein a plurality of line-shaped light sources are provided so as to cover all light receiving regions of the integrated thin film solar cell module , and lighting of each light source is sequentially switched. Module evaluation device. 4. The integrated thin-film solar cell module evaluation apparatus according to claim 1, wherein the light source includes a linear LED or a white LED or a lamp arranged linearly. 5. The light source according to claim 1, wherein the light source includes a plurality of LEDs each having a different emission color, and is configured to be able to switch the color of the LED that emits light. The evaluation apparatus of the integrated thin film solar cell module described. The light source includes a plurality of linearly arranged LED rows, the light emission colors of the LEDs in each row are different from each other, and the color of the light emitting LEDs can be switched. 6. The integrated thin film solar cell module evaluation apparatus according to claim 4, wherein the evaluation apparatus is an integrated type thin film solar cell module . 7. The integrated thin-film solar cell module evaluation apparatus according to claim 1, wherein the light source is provided with a light diffusing plate that makes light intensity uniform. 8. The integrated thin-film solar cell module evaluation apparatus according to claim 1, wherein the light source includes a filter that adjusts a spectrum of irradiation light. The integrated thin-film solar cell module strip cells are connected in series, and irradiates a long line-shaped light in the serial connecting direction of the cell, moving the line-shaped light receiving portion stepwise, the integrated thin-film solar current during light irradiation of the battery module - evaluation method of an integrated thin-film solar cell module, wherein the measurement of the voltage characteristics it intends automatically line in conjunction with the movement of the step-like. Based on the integrated thin-film solar cell module light receiving plane overall measurement result of the evaluation method of an integrated thin-film solar cell module according to claim 9, wherein evaluating the characteristic variation in the plane. 11. The integrated thin film solar cell module evaluation method according to claim 9 or 10, wherein classification or selection is performed according to a measurement result of current-voltage characteristics during light irradiation . The method for evaluating an integrated thin-film solar cell module according to any one of claims 9 to 11, wherein the color of the irradiation light is changed and the current-voltage characteristics at the time of light irradiation for each color are measured. The integration according to any one of claims 9 to 12, wherein a temperature of an environment in which the integrated thin film solar cell module is arranged is changed, and current-voltage characteristics at the time of light irradiation at different temperatures are measured. Evaluation method of a type thin film solar cell module .

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