JP2012215459A - Defect inspection device and defect inspection method for solar battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a defect inspection device for a solar battery, capable of detecting a position of a defect in a short time.SOLUTION: A defect inspecting device for a solar battery comprises: voltage application means 4 for applying a voltage having a direction opposite to a forward voltage, to solar battery cells adjacent to each other; magnetic field detection means 5 for, when applying the reverse voltage, detecting intensity of a magnetic field generated by a current flowing along the solar battery cell, in association with a position along a flowing direction of the current; and defect position specification means for specifying the presence or absence of an electrical defect generated in the solar battery cell and a position of the defect, based on output distribution of the magnetic field intensity in association with the position.

Description

  The present invention relates to a defect inspection apparatus and a defect inspection method for detecting defects generated in a manufacturing process of a solar cell, and in particular, a solar cell manufacturing apparatus incorporating the defect inspection apparatus and the defect inspection method in a solar cell manufacturing process. And a manufacturing method.

  Recently, solar cells have been attracting attention and developed as part of global warming prevention measures. Among such solar cells, a thin-film solar cell has a structure in which, for example, a surface electrode (transparent), amorphous silicon (thin film silicon), and a back electrode made of metal are sequentially laminated on a transparent substrate such as glass or plastic. ing. Amorphous silicon is formed in a p-type-i-type-n-type three-layer structure from the substrate side. When light is irradiated from the transparent substrate side, the light passing through the transparent substrate and the surface electrode hits the amorphous silicon. Electricity is generated in the amorphous silicon to generate power in the solar cell. This amorphous silicon is positive on the p-type side and negative on the n-type side, and has diode characteristics.

  By the way, in such a thin film solar cell, when amorphous silicon is formed on the surface electrode in the manufacturing process, defects such as pinholes may occur in the amorphous silicon. When this pinhole occurs, the electrode material may enter the pinhole in the subsequent step of forming the back electrode on the amorphous silicon, and the electrode portion that has entered the pinhole is between the front electrode and the back electrode. There is a risk of causing a short circuit. Due to this short circuit (short circuit), the conversion efficiency of the thin film solar cell (the efficiency of converting the amount of light applied to the solar cell into electricity) is lowered, and the performance of the thin film solar cell is remarkably deteriorated.

  Patent Document 1 discloses a technique in which a reverse voltage is applied to a plurality of cells constituting a solar cell, a predetermined current is passed through the defective portion, and the defective portion is altered and insulated by Joule heat.

  Patent Document 2 discloses a technique in which a plurality of probes are arranged along the longitudinal direction of a cell and the plurality of probes are brought into contact with the cell to burn out a defective portion as a solution to the drawbacks of Patent Document 1. Is disclosed. According to the technique disclosed in Patent Document 2, since a plurality of probes are in contact with a cell at a plurality of locations, a current value necessary for repairing a defective portion by burning by selecting an appropriate probe. In other words, the applied voltage value can be lowered.

  In Patent Document 3, the probe is shaped into a roller shape, and the position of the defect is accurately detected while rolling the roller in the longitudinal direction of the cell while applying a reverse voltage via the roller. A technique is disclosed in which a current can be passed in the reverse direction (or forward direction) to burn out the defective portion. According to Patent Document 3, the current value can be further reduced as compared with the method disclosed in Patent Document 2, and a defective portion can be burned out with a minimum current. Moreover, the number of probes (in this example, the number of rollers) may be only the number of cells, and as a result, it is possible to expect an effect of suppressing an increase in cost of the apparatus and improving durability.

  Patent Document 4 discloses a technique in which a large current is not exchanged between the probe and the cell surface, and an internal defect of the battery is examined in a non-contact manner. In other words, a defect inspection method is disclosed in which light is applied after a load is connected to a solar cell, or an external current source is connected to the solar cell to flow current. In this defect inspection method, if there is a current flowing through the cell, the magnetic field generated by the current can be observed. By capturing the magnetic field components with magnetic sensors arranged in three orthogonal directions, performing image processing in all three-dimensional directions, and displaying the results, various internal defects can be found.

JP 2008-091674 A JP-A-10-004202 JP 2010-232547 A JP 2010-171065 A

  The technological progress of thin-film solar cells is remarkable, and the types and characteristics of solar cells are diversifying. For example, in the thin film silicon solar cell and the compound solar cell, the types such as CIS solar cell, CIGS solar cell, and CdTe solar cell are increasing depending on the type of rare metal used. However, as thin-film solar cells diversify, the application time and voltage value of the reverse voltage applied to remove the short-circuit portion vary depending on the type and characteristics of the thin-film solar cells. Appropriate tuning must be performed on the thin-film solar cells flowing through.

  Thus, in a production line that actually manufactures a thin film type solar cell, in order to remove a short-circuited portion of the thin film type solar cell, the tact time is shortened and tuning according to the characteristics of the diversified thin film type solar cell is performed. Although there are three problems, the documents 1-4 listed above do not describe these problems.

  Further, in the technique disclosed in Patent Document 1 in which a current is passed through a defective portion to burn out the defective portion, the distance between the defective portion and the probe cannot be determined, and accordingly, an excessive voltage must be applied. However, an excessive current flows through the defective portion, which may damage the solar cell. From this point of view, it is desired that the short-circuit portion is specified and the short-circuit portion removal process is performed with a minimum repair current.

  Furthermore, according to the technique in which a plurality of probes disclosed in Patent Document 2 are arranged in contact with a cell to inspect the defect portion and the defect portion is burnt out, the defect portion is burned out while maintaining a low current flowing through the cell. And the initial purpose can be achieved. However, the number of probes is enormous, which not only increases the cost of the equipment, but also increases the durability of the probe and the use of noble metals such as rhodium to improve the contact resistance with the solar cell. There is a problem that the device becomes very expensive. In addition, since the probe has a structure of a combination of a rod and a pipe, mechanical wear cannot be avoided, the frequency of failure of the device increases, and periodic replacement of the probe is necessary. is there. In addition, it is necessary to ensure a sufficient contact pressure between the probe and the surface of the solar cell, and as the number of probes increases, the physical pressure that presses the solar cell also increases, and the design of the device increases accordingly. There is a problem that must be designed.

  Furthermore, in the technique of detecting a defective portion with a roller-type probe disclosed in Patent Document 3 and burning the defective portion, an optimal material that can supply current to the cell surface with a low resistance value via the roller There are still some issues for practical application, such as a small number of cases.

  In addition, according to the method of observing the magnetic field generated by the current disclosed in Patent Document 4, it is a technique that has not been used so far in that it focuses attention on magnetism. As a result, the magnetic sensor is moved over the entire surface of the solar cell. In addition to adopting a very time-consuming method of image processing, no solution is presented for the unique problem in the thin-film solar cell production line of short-circuit detection. .

  The object of the present invention is to provide a solar cell defect inspection apparatus and method that can detect the position of a defective portion in a short time.

  Another object of the present invention is to incorporate a solar cell defect inspection apparatus and method capable of detecting the position of a defective portion into a manufacturing process, and to improve work efficiency and maintain product quality. It is in providing the manufacturing apparatus and manufacturing method of a battery.

According to the invention of the embodiment according to claim 1,
A solar cell in which a large number of solar cells are arranged in parallel along a substantially first direction on an insulating substrate, and each solar cell is along a substantially second direction perpendicular to the first direction. In the extended solar cell defect inspection system,
First voltage applying means for applying a first voltage in a direction opposite to the forward voltage to the solar cells adjacent to each other;
A magnetic field that detects the strength of the magnetic field generated by the current flowing along the second direction of the solar cell in association with the application of the first voltage in the reverse direction in association with the position along the second direction. Detection means;
Based on the output distribution of the strength of the magnetic field associated with the position along the second direction, the presence or absence of an electrical defect occurring in the solar battery cell and the location of the defect in the defect A defect location specifying means for specifying a location;
A defect inspection apparatus for a solar cell is provided.

According to the invention of the embodiment according to claim 2,
When the generated magnetic field is decomposed into a first magnetic field component along a third direction substantially orthogonal to a plane including the first and second directions and a second magnetic field component along the first direction,
The solar cell defect inspection apparatus according to claim 1, wherein the magnetic field detection unit is arranged to detect at least one of the first and second magnetic field components.

According to the invention of the embodiment according to claim 3,
The magnetic field detection unit includes a magnetic sensor unit that detects the strength of the magnetic field, and a movement unit that includes a position detection unit that moves the magnetic sensor unit along the second direction and detects a movement position associated with the movement. A solar cell defect inspection apparatus according to claim 1 or claim 2 is provided.

According to invention of embodiment concerning Claim 4,
The said moving means is set to the speed selected from the several moving speed according to the command from the outside, and moves the said magnetic sensor along the said 2nd direction, It is characterized by the above-mentioned. A defect inspection apparatus for a solar cell is provided.

According to the invention of the embodiment according to claim 5,
The magnetic field detection unit includes a plurality of magnetic sensor units arranged at predetermined intervals along the second direction, and the defect position specifying unit is configured to output the defect from the outputs of the plurality of magnetic sensor units. The solar cell defect inspection apparatus according to claim 1 or 2 is provided.

According to the invention of the embodiment according to claim 6,
The voltage application means includes a power supply unit that applies a voltage obtained by superimposing an AC voltage having a certain AC frequency on a DC voltage corresponding to the first voltage in the reverse direction to the adjacent solar cells, 6. The solar cell defect inspection apparatus according to claim 1, wherein the magnetic field detection means includes extraction means for extracting the AC frequency component from the output signal.

According to the invention of the embodiment according to claim 7,
The solar cell defect inspection apparatus according to claim 6, wherein the extraction unit is any one of a resonance circuit unit, a bandpass filter unit, a synchronous detection circuit unit, a quadrature detection circuit unit, and a Fourier transform circuit. Provided.

According to the invention of the embodiment according to claim 8,
The magnetic field detection means includes any one of a Hall element sensor, an MI sensor, a sensor including a coil, a sensor including a resonance circuit including a coil and a capacitor, or a fluxgate sensor. A defect inspection apparatus for a solar cell according to any one of claims 1 to 6 is provided.

According to the invention of the embodiment according to claim 9,
9. The sun according to claim 1, further comprising a calibration unit that applies a predetermined current to the solar battery cell and executes a calibration process for correcting an error factor of the magnetic field detection unit. A battery defect inspection apparatus is provided.

According to the invention of the embodiment according to claim 10,
The voltage applying means includes
In addition to the first voltage applying means for applying the first voltage in the reverse direction to the one end region of the solar cell, the forward voltage is applied to the other end region of the solar cells adjacent to each other. A second voltage applying unit configured to apply a second voltage in the reverse direction, wherein the magnetic field detecting unit determines the strength of the magnetic field generated by the current flowing in the region between the one end region and the other end region; It detects in relation to the position along 2 directions, The defect inspection apparatus of the solar cell of Claims 1-9 is provided.

According to the invention of the embodiment according to claim 11,
The voltage application means includes a voltage application section that applies the first voltage and a conveyance means that conveys the voltage application section along the second direction, or a place specified by the defect position specification means or this place The voltage application unit is transported to a region including the voltage, and a reverse voltage boosting unit capable of boosting the voltage until the current no longer flows in the reverse direction by applying the voltage in the reverse direction while gradually increasing is provided. A solar cell defect inspection apparatus according to any one of claims 1 to 9 is provided.

According to invention of embodiment concerning Claim 12,
A solar cell manufacturing apparatus including the defect inspection apparatus according to claim 1 is provided.

According to the invention of the embodiment according to claim 13,
A solar cell in which a large number of solar cells are arranged in parallel along a substantially first direction on an insulating substrate, and each solar cell is along a substantially second direction perpendicular to the first direction. In the manufacturing method of the extended solar cell,
A first voltage application step of applying a first voltage in a direction opposite to the forward voltage to the solar cells adjacent to each other;
A magnetic field that detects the strength of the magnetic field generated by the current flowing along the second direction of the solar cell in association with the application of the first voltage in the reverse direction in association with the position along the second direction. A detection process;
Based on the output distribution of the strength of the magnetic field associated with the position along the second direction, the presence or absence of an electrical defect occurring in the solar battery cell and the location of the defect in the defect A defect location identifying step for identifying the location;
A defect inspection method for a solar cell is provided.

According to the invention of an embodiment according to claim 14,
The defect position detecting step includes a magnetic field distribution detecting step for associating a change in the magnetic field distribution with a position along the second direction, and the second direction in which the change in the magnetic field distribution is greater than or equal to a predetermined magnitude. The method for inspecting a defect of a solar cell according to claim 13, further comprising the step of identifying a spot or area as the defect position.

According to the invention of the embodiment according to claim 15,
15. The defect position detecting step includes a step of examining a strength of a magnetic field associated with a moving position while moving a magnetic field sensor along the second direction. Inspection method for solar cells.

According to the invention of an embodiment concerning claim 16,
In the defect position detection step, a region in which a defect is generated is determined by roughly examining the strength of the magnetic field while moving at a relatively high speed, and based on the result of this step, the region with a low suspicion of the defect is The above-mentioned method includes a step of examining the area having high suspicion of the defect at a high speed and a high accuracy while moving the magnetic sensor relatively slowly at a second speed slower than the first speed. A defect inspection method for a solar cell according to claim 15 is provided.

According to the invention of an embodiment according to claim 17,
The defect position detecting step includes a step of substantially simultaneously checking a magnetic field at a plurality of locations with a plurality of sensors along the second direction, and further including a step of identifying a region where a defect exists from these magnetic field data. A defect inspection method for a solar cell according to claim 13 or claim 14 is provided.

According to the invention of an embodiment according to claim 18,
The voltage applying step includes a step of applying a voltage on which an alternating voltage having an alternating frequency at a direct current voltage corresponding to the first voltage in the reverse direction is superimposed on the adjacent solar cells, and detecting the magnetic field The means further comprises the step of extracting the AC frequency component from the output signal, and the solar cell defect inspection method according to any one of claims 13 to 17 is provided.

According to the invention of an embodiment according to claim 19,
The voltage application step includes
What is the forward voltage in the other end region of the solar cells adjacent to each other in addition to the first voltage application step of applying the first voltage in the reverse direction to the one end region of the solar cell? A second voltage application step of applying a second voltage in the reverse direction, wherein the magnetic field detection step determines the strength of the magnetic field generated by the current flowing in the region between the one end region and the other end region. The solar cell defect inspection method according to any one of claims 13 to 18, wherein the detection is performed in association with a position along two directions.

According to the invention of an embodiment according to claim 20,
The voltage applying step includes a transporting step that is performed while transporting the voltage applying unit that applies the first voltage along the second direction, and the portion specified in the defect position specifying step or the region including this portion. The above-mentioned step further comprising the step of conveying the voltage application unit and applying the voltage in the reverse direction while gradually increasing the voltage until the current stops flowing in the reverse direction. A defect inspection method according to claims 13 to 19 is provided.

According to the invention of an embodiment according to claim 21,
The manufacturing method of the solar cell containing the defect inspection method of Claim 13-19 mentioned above is provided.

  According to this invention, the soundness of the electrical insulation state between the electrodes of the solar cell is inspected, the location where a defect such as a pinhole is generated is specified, and a repair current is directly applied to the defective location. It is possible to provide a defect inspection apparatus and method that can be repaired.

  Moreover, according to this invention, the manufacturing apparatus of the solar cell which can improve the working efficiency including this defect detection and repair, and can maintain the quality of a product can be provided.

  In addition to the short circuit described above, for example, when processing a cell section, the section processing is insufficient, the electrical resistance between two adjacent cells is low, and there is a problem that part of the current leaks. Therefore, in the following description, the short circuit and the current leakage are collectively referred to as “defect”, and the portion is referred to as “defect portion”. In addition, if this invention is applied in the thin film solar cell with an extremely large area, the effect will be acquired more clearly.

  According to various embodiments of the solar cell manufacturing apparatus and manufacturing method of the present invention, the following technical effects can be realized in more detail.

  (1) The position of the defective part can be detected in a short time.

  (2) The position of the defect can be identified very clearly even by unskilled field workers.

  (3) It is not necessary to apply a large pressing force to the surface of the solar cell as in the prior art, and therefore the risk of scratching the solar cell as an inspection object can be greatly eliminated.

  (4) Since the position of the defective portion can be identified with extremely high accuracy, the voltage value required for repair (hereinafter referred to as repair in this specification) can be suppressed to a low level. It is possible to prevent the battery from being damaged.

  (5) Since the individual processes are performed in parallel, it is possible to meet the demand for shortening the tact time.

  (6) According to the embodiment in which the presence / absence of the defective portion can be determined instantaneously without determining the presence / absence of current, the inspection can be performed while reducing the cost of the manufacturing apparatus.

  (7) According to the embodiment focusing on the phenomenon that if a probe for applying a reverse voltage is arranged at both ends of the cell and there is a current flowing through the defect, the magnetic direction reverses before and after the defect. In this case, it is possible to realize defect position detection with higher sensitivity.

  (8) Even when the sensor that detects the defective part fails and the sensor output is lost, the output of another detection sensor can detect the defect without reducing the probability of missing the defect detection. A possible inspection system can be provided.

  (9) According to the embodiment in which the reverse voltage applied to the solar cell is set to a voltage obtained by superimposing alternating current on direct current (direct current + alternating current), and only the applied alternating current frequency component is extracted and the noise frequency component is removed. For example, it is possible to provide a defect inspection apparatus for a solar cell that can perform a defect inspection that is resistant to noise.

  (10) From the viewpoint of durability, it is very advantageous compared to probes, and in recent years, small and inexpensive magnetic sensors have begun to be put on the market. Therefore, according to the embodiment in which these magnetic sensors are arranged in a matrix. In this case, the position of the defective part can be specified easily and in a short time.

It is a top view which shows typically the defect inspection apparatus of the solar cell which concerns on 1st Embodiment of this invention. FIG. 2 is a schematic cross-sectional view illustrating the cell structure of the solar battery 2 shown in FIG. 1. 3 is a current-voltage graph showing a constant current drooping characteristic of the control unit shown in FIG. 1. It is a graph which shows the relationship between the cell position calculated by simulation along the III-III cross section shown by FIG. 1, and the magnitude | size of a perpendicular magnetic field. It is a top view which shows typically the defect inspection apparatus of the solar cell which concerns on 2nd Embodiment of this invention. 5 is a horizontal magnetic field graph showing the relationship between the cell position calculated by simulation along the VV cross section and the magnitude of the magnetic field in the defect inspection apparatus shown in FIG. 4. In the defect inspection apparatus shown in FIG. 1, in the case where the defect portion D is continuously generated in the adjacent cells Cn and Cn + 1, the relationship between the cell position calculated by simulation along the III-III cross section and the magnitude of the magnetic field is shown. It is a graph of the horizontal magnetic field shown. In the defect inspection apparatus shown in FIG. 1, the distribution of the horizontal magnetic field detected with respect to the cell position along the III-III cross section when the defect portion D occurs in the cells Cn and Cn + 2 adjacent to both sides of a certain cell Cn + 1. It is a graph to show. In the defect inspection apparatus shown in FIG. 4, a graph showing the distribution of the horizontal magnetic field detected with respect to the cell position along the VV cross section when the defect portion D occurs in the adjacent cells Cn and Cn + 1 continuously. It is. In the defect inspection apparatus shown in FIG. 4, in the case where a defect portion D occurs in cells Cn and Cn + 2 adjacent to both sides of a certain cell Cn + 1, the distribution of the horizontal magnetic field detected for the cell position along the line VV. It is a graph which shows. It is a top view which shows typically the defect inspection apparatus of the solar cell which concerns on 3rd Embodiment of this invention. It is a defect inspection apparatus shown in FIG. 10, Comprising: It is a top view which shows typically the solar cell with which the several defect has arisen in the same cell. It is a top view which shows typically the defect inspection apparatus of the solar cell which concerns on 4th Embodiment of this invention. It is a wave form diagram which shows the reverse voltage waveform applied to the probe in the defect inspection apparatus of the solar cell shown to FIG. 12A. It is a block diagram of the circuit which processes the signal in the defect inspection apparatus of the solar cell shown to FIG. 12A. It is a top view which shows typically the defect inspection apparatus of the solar cell which concerns on 5th Embodiment of this invention. It is a top view which expands and shows typically a part of defect inspection apparatus of the solar cell shown by FIG. 13A. It is the schematic which shows roughly the arrangement | positioning of each part in the manufacturing apparatus provided with the defect inspection part to which 5th Embodiment is applied seeing in the vertical cross section. It is a top view which shows typically the defect inspection apparatus of the solar cell which concerns on 6th Embodiment of this invention. FIG. 15B is a plan view schematically showing an enlarged part of the defect inspection apparatus for a solar cell shown in FIG. 15A. It is the schematic which shows roughly arrangement | positioning of each part in the manufacturing apparatus provided with the defect inspection part to which 6th Embodiment is applied. It is a schematic diagram which shows an example of the calibration process in the manufacturing apparatus of the solar cell which concerns on embodiment of this invention. It is a schematic diagram which shows the other example of the calibration process in the manufacturing apparatus of the solar cell which concerns on embodiment of this invention. It is a schematic diagram which shows the further another example of the calibration process in the manufacturing apparatus of the solar cell which concerns on embodiment of this invention.

  Hereinafter, a solar cell manufacturing apparatus and a manufacturing method according to embodiments of the present invention will be described in detail.

  In the following embodiments, a sensor that can detect a DC magnetic field, such as a Hall element sensor or an MI (Magneto-Impedance) sensor, can be used as the magnetic sensor. These sensors are available in very small size and at reasonable prices.

[First Embodiment]
FIG. 1 schematically shows an inspection process unit for inspecting a solar cell in the solar cell 2 manufacturing apparatus according to the first embodiment of the present invention. FIG. 2A schematically shows the structure of the solar cell 2 illustrated in FIG. 1 in cross section.

  The solar cell 2 shown in FIG. 2A is referred to as a thin film solar cell, and is configured by a plurality of striped solar cells Cj arranged in parallel. As an example, each solar cell Cj has a transparent and relatively high-resistance surface electrode 14 such as ITO on a transparent substrate 12 such as glass or plastic, a surface electrode 14 made of amorphous silicon (thin film silicon) 16 and a metal. Compared to the above, the back electrode 18 made of a metal having a sufficiently low resistance is sequentially laminated.

  In recent years, a resin material is used as the transparent substrate 12 for the purpose of reducing the weight of a flexible transparent material or a solar cell. The amorphous silicon 16 is formed in a three-layer structure of p-type-i-type-n-type amorphous silicon 16-1, 16-2, 16-3 from the substrate 12 side. When the solar cell Cj is irradiated with light from the transparent substrate 12 side, the light passing through the transparent substrate 12 and the surface electrode 14 is irradiated to the amorphous silicon 16, and electricity is generated in the amorphous silicon 16 as the power generation unit. Power is generated in the solar cell. The amorphous silicon 16 has a diode characteristic that generates a forward voltage between the front electrode 14 and the back electrode 18 with the p-type side set to positive and the n-type side set to negative. The amorphous silicon 16 has a thickness T0 of about 1 μm, for example, and the back electrode 18 is formed to have a width L0 of about 1 cm, for example. In the striped solar cell Cj, the side end portion of the back electrode 18 is connected to the surface electrode 14 of the adjacent striped solar cell Cj, and a plurality of solar cells Cj are connected in series to each other. 2 is constituted. As described above, the solar cell 2 is manufactured in a finished product as a solar cell in which a large number of vertically and vertically striped cells Cj are juxtaposed in the horizontal direction and these cells are electrically connected in series. Each cell Cj is given a supplementary note j meaning the j-th (integer) cell to identify the cell. FIG. 1 shows a cell Cn and a cell Cn + 1 as a cell having the cell Cj.

  2A is shown to help understanding of the inspection apparatus for inspecting the solar cell of the present invention. The structure of the solar cell shown in FIG. 2A and the material of each part for understanding this structure are shown as an example. Illustrated. Therefore, it is clear that the present invention is not applied only to the solar battery cell having this structure and the material composing the structure. It is obvious that the present invention can be applied to various structures or various types as long as the solar battery 2 includes a plurality of solar cells Cj.

  In the thin film solar cell 2 as described above, when the amorphous silicon 16 is formed on the surface electrode 14 in the manufacturing process, a defect D such as a pinhole may occur in the amorphous silicon 16 as the power generation unit. is there. When this defect D such as a pinhole occurs, in the subsequent step of forming the back electrode 18 on the amorphous silicon 16, the electrode material of the back electrode 18 enters the pinhole, and the electrode portion that has entered the pinhole A short circuit is caused between the electrode 14 and the back electrode 18.

  In the manufacturing apparatus shown in FIG. 1, the solar cell 2 is in a state in which the light receiving surface of the solar cell 2 on which sunlight is incident (in this specification, this light receiving surface is simply referred to as the upper surface) is directed downward. It has been transferred to the inspection process. Therefore, in the inspection process, the back electrode 18 provided on the surface facing the light receiving surface of the solar cell (in this specification, simply referred to as the back surface) is directed upward.

  In the manufacturing apparatus shown in FIG. 1, in order to detect this defect D, a large number of probes Pj (in FIG. 1, symbols Pn and Pn + 1 are attached as typical probes) are striped solar cells C. Are arranged along the arrangement direction of the solar cells Cj so as to be in contact with the back surface electrode 18. In addition, a plurality of magnetic sensors Sj for detecting magnetism (in FIG. 1, symbols Sn and Sn + 1 are attached as typical magnetic sensors) are conveyed on the boundary between the striped solar cells Cj. It is placed on the gondola G as a part. The gondola G is moved along the longitudinal direction of the striped solar cell C, and the magnetic sensor Sj is moved along with the movement of the gondola G. The magnetic field HV is moved along the longitudinal direction of the solar cell Cj along with the movement. It is detected (detected). In the region indicated by the section CC in FIG. 1, the change in the detected magnetic field HV detected by the magnetic sensors Sn and Sn + 1 is shown as a characteristic graph on the left side of FIG. The CC cross section corresponds to the longitudinal direction of the solar cell Cn, and the detection magnetic field HV has a positive z direction in the coordinate system defined at the lower right in the drawing of FIG.

  As coordinate axes in this coordinate system, a coordinate axis in a space where the solar cell 2 is arranged with reference to a state where the solar cell is installed outdoors is defined. In FIG. 1, since the back side of the solar cell 2 is shown, the longitudinal axis x of the cell Cj is determined to be positive on the paper, and the left axis is positive, and the longitudinal y axis of the cell Cj is on the paper. The upper part is positive. In addition, the above-described z-axis is set downward facing the paper surface. In the embodiment described later, this coordinate axis is similarly set. Since this coordinate axis is defined to indicate the back side of the solar cell 2, there is a risk of misunderstanding of the orientation of the solar cell 2, etc. From the viewpoint of avoiding confusion based on the misunderstanding, the coordinate axis is determined for each embodiment. I am writing.

  The number of defect portions D generated in one solar cell varies depending on the manufacturing technique, and does not always occur at a constant number even in the same manufacturing process. In this specification, in order to help the understanding of the invention, a case where there is one defect is first described, and then a solar cell having a plurality of defects is described.

  As shown in FIG. 1, the inspection apparatus includes a detection circuit unit 5 including a power supply unit 4 and a control unit 6. It is assumed that a defect D occurs in the nth cell Cn of this solar cell. At the time of inspection, a reverse voltage is applied from the power supply control unit 5 to the end portion (the uppermost portion in the drawing) of each solar cell Cn from the probe Pn. Here, since the solar battery cell Cn has a diode characteristic, the power supply control unit 5 refers to the applied voltage from the probe Pn as a reverse voltage as described above, and is in a direction opposite to the direction in which the current flows during power generation. Defined as voltage.

  As shown in FIG. 1, the positive pole of the external power supply 4 is connected to the probe Pn that contacts the nth cell Cn, and the negative pole of the external power supply 4 is connected to the probe Pn + 1. A control unit 6 is preferably connected between the external power supply 4 and the probe Pn. Along with the connection of the external power supply 4, the current from the external power supply 4 flows toward the lower side of the figure along the y axis, as indicated by the arrow M <b> 1 of the back surface electrode 18 of the solar battery cell Cn. This current passes through the inside of the solar cell Cn (amorphous silicon layer) and reaches the surface electrode 14 in the defect portion D generated in the solar cell Cn, and is connected to the surface electrode 14 at the position of the defect portion D. It flows into the back electrode 18 of the adjacent cell Cn + 1. Then, the current flows upward in the figure along the y-axis direction of the back electrode 18 of the cell Cn + 1, reaches the probe Pn + 1, and is returned to the external power supply 4.

  Here, there is also a current that flows toward the portion other than the back surface electrode 18 through the front surface electrode 14 of the solar battery cell Cn + 1. However, the electrical resistance of the front surface electrode 14 is more extreme than the electrical resistance of the back surface electrode 18 as described above. Therefore, most of the current flows through the back electrode 18 and the current reaching the vicinity of the probe Pn + 1 through the front electrode 14 can be ignored.

  The control unit 6 connected between the solar cells Cn, Cn + 1, the probes Pn, Pn + 1 and the external power supply 4 has a constant current drooping characteristic as shown in FIG. 2B. The current flowing through the cells Cn and Cn + 1 and the applied voltage are limited to a predetermined voltage value Vmax and current value Imax or less due to the constant current drooping characteristics of the control unit 6, and an excessive current flows or an excessive voltage. Is prevented from being applied. The control unit 6 preferably has a current detection function for detecting current. By this current detection function, it is possible to immediately detect that there is a defective portion D in this solar cell Cn from the flow of current.

  However, it should be noted that it is impossible to detect where the defect D is in the solar cell Cn and “how many” in the longitudinal direction of the cell from only the current information accompanying the current detection. .

  The current loop that reciprocates the back electrode 18 of the cells Cn and Cn + 1 forms a magnetic field around the current path. In order to detect this magnetic field, a magnetic sensor Sj is arranged at the boundary between arbitrary adjacent cells Cj and Cj + 1. In the above-described example, the magnetic sensor Sn is disposed at the boundary between the adjacent cells Cn and Cn + 1. These magnetic sensors Sj are placed on a gondola G (indicated by a dotted line) driven by the drive unit 7, and the gondola G causes the magnetic sensor Sj to have a sensor upper limit position L1 and an arrow M1 and M2, respectively. It moves along the longitudinal direction of the photovoltaic cell Cn between the sensor lower limit positions L2. This movement of the magnetic sensor Sj is detected by a position information sensor such as an encoder 7A as a position detection unit provided in the motor of the drive unit 7 that moves the gondola G, and a processing unit as a position signal indicating the position of the magnetic sensor Sj. 9 is output. The direction of the magnetic sensor Sj shown in FIG. 1 is selected and arranged to be sensitive to the magnetic Hv in the direction perpendicular to the back electrode 18.

  The gondola G starts to move from the sensor upper limit position L1 closest to the probe Pn and is moved toward the sensor lower limit position L2 along the longitudinal direction of the solar battery cell Cn as shown by an arrow M1 in FIG. Along with this movement, the magnetic sensor Sn detects and outputs downward magnetism H (Sn) along the z-axis, as shown in the characteristic graph. The magnetic output H (Sn) is theoretically maintained substantially constant until the sensor Sn is detected from the sensor upper limit position L1 until the defect portion D is detected, and the magnetic output H (Sn) is passed through the defect portion D. ) Is drastically reduced. In addition, the magnetic output H (Sn) is maintained at substantially 0 between the position of the defective portion D and the sensor lower limit position L1. Therefore, the portion where the magnetic output H (Sn) changes abruptly corresponds to the defective portion D, and it can be determined that this portion is the defective portion D. At this time, the magnetic output H (Sn + 1) of the adjacent sensor Sn + 1 has a lower absolute value than the output H (Sn) of the sensor Sn and is output in the opposite phase, but similarly passes through the defective portion D. When this occurs, the output H (Sn + 1) is suddenly changed to zero. The magnetic output H (Sn) and the magnetic output H (Sn + 1) are converted into electrical signals of appropriate levels by a signal processing circuit (not shown) and supplied to a defect detection unit (not shown) to determine whether there is a defect. The position is identified.

  In this detection system, since the defect D can be detected by any of the outputs H (Sn) and H (Sn + 1) from the two sensors Sn and Sn + 1, the detection system has redundancy. Even if this sensor fails, there is an advantage that the probability of missing a defective portion can be reduced.

  Here, for the purpose of simplifying the drawing, one reverse voltage power source applied from the outside is illustrated in the detection circuit unit 5, but the reverse voltage is similarly applied to all adjacent cells Cj. Obviously, a power supply unit 4 and a control unit 6 are provided. As an example of providing such a large number of power supplies in a circuit, there is a circuit exemplified in Japanese Patent Application Laid-Open No. 2010-232547.

  FIG. 3 shows the magnitude of the magnetic field calculated by simulation along the section III-III shown in FIG. The graph of FIG. 3 is calculated by a simulation under the following premise. That is, the current density is uniform within the cell electrode cross section along the line III-III, and flows downward except in the vicinity of the defect portion in FIG. Further, in the defect portion D, the current direction has a horizontal component, but this horizontal component is ignored. In addition, the calculation is performed on the assumption that the magnetic field sensor Sj is located at a height h (h = 0.5L0) from the surface of the cell Cj. Here, L0 corresponds to the width of the cell Cj. The vertical axis in FIG. 3 displays the calculated magnetic field as non-dimensional (standardized). The value obtained by multiplying this value by the current density I0 per unit length in the width direction of the cell cross section and dividing by 2π is the original magnetic field strength (unit: A / m). Further, the horizontal axis of FIG. 3 corresponds to the cell arrangement of the solar cells Cj, and the areas of the cells (Cn−1, Cn, Cn + 1, Cn + 2) are also written below the horizontal axis.

  According to the simulation results, it can be seen that the vertical magnetic field shows the maximum value at the boundary between the cell Cn having the short-circuited portion and the adjacent cell Cn + 1, and the direction is the z-axis direction, that is, the vertical downward direction. In the first embodiment shown in FIG. 1, the reason why the magnetic sensor Sj is positioned at the cell boundary is that the vertical magnetic field shows the maximum value at the boundary. At the position separated from the boundary position by the cell width L0 on both sides, although the direction of magnetism is reversed, magnetism appears, and the magnetism can be observed by the sensor Sj provided on the adjacent boundary line. Since this detection redundancy is not actually one, but a large number of sensors have redundancy, the embodiment shown in FIG. 1 can produce a manufacturing apparatus that is very robust against sensor failure. it can.

  Next, a case where two defective portions D1 and D2 (not shown) are generated at two locations (x1, y1) and (x2, y2) separated by the same cell Cj will be described. When the defect D1 is short-circuited with almost no resistance value, the flowing current value is strong up to the first defect part D1, and basically does not flow from there to the next defect part D2. Therefore, the magnetic output H (Sj) from the sensor Sj drops sharply at the position of the first defective portion and is not output after that. For these types of defects, there is a risk of oversight in defect inspection. However, when the defects D1 and D2 are defects having a leakage level due to incomplete cell boundary section work, the sensor output suddenly drops at the first defect D1, and then the short-circuited position at the next defect D2 Then it drops again and drops to zero. Therefore, for these types of defects, if attention is paid to the place where the output suddenly drops in the magnetic output H (Sj), even if there are two defective portions in the same cell, it is possible to detect and specify the position. it can. Similarly, even when there are m defective parts of the latter type in the same cell, the magnetic output is suddenly dropped m times, so that the defective part (location) is the encoder of the drive unit 7 of the gondola G The position output from 7A can be easily specified. According to the first embodiment, when there are a plurality of defects in the same cell Cj, an oversight may occur depending on the type of the defect portion D, but even in that case, at least the defect portion closest to the probe or the most A defective portion having a low resistance value can be detected. This point will be described in detail later.

  In the first embodiment, since the control unit 6 has a current detection function, the cell Cj with the defective portion D can be found based on the result of the current detection. In the control unit 6, if any cell has a current of 0, there is no defective portion D, and the subsequent inspection can be omitted and the process can proceed to the next step. Further, when a current is detected from any one of the cells Cj, it is only necessary to specify the position based on the magnetic sensor Sj and the output of the encoder 7A while paying attention to only the cell Cj, and the work can be simplified. Since the defect positioning operation is performed by continuously moving the gondola G, it is not necessary to repeat the operations of driving, accelerating, decelerating, and stopping, and the operation time can be saved.

  Even if the controller 6 does not have a current detection function, the defect portion D can be inspected basically from the output of the magnetic sensor Sj. Also in the apparatus shown in FIG. 1, in most cases, the inspection work for the defective portion D can be proceeded without any problem. However, it is preferable that the presence or absence of the output from the magnetic sensor Sj of all the cells Cj is first checked, and then the position is searched, and the defective portion D can be detected reliably. However, when the defective portion is generated in the immediate vicinity of the probe, the defective portion D may be missed without this current detection function. In particular, since the gondola G has a mechanical size, it cannot be excluded that the defective portion D may be missed.

  There is no problem when the output of the magnetic sensor Sj is handled as a continuous quantity, but when it is handled as a discrete quantity, there are the following problems and countermeasures are required.

  At present, thin film solar cells including amorphous silicon have about 100 striped cells Cj. In many manufacturing apparatuses, the inspection process is electrically switched for each cell Cj. On the other hand, in the gondola G according to the embodiment as shown in FIG. 1, it is reasonable to drive the motor at a constant speed as much as possible from the viewpoint of shortening the manufacturing time. Then, the obtained sensor output is not a continuous quantity, but becomes discrete data obtained at every sampling period. Although it depends on the moving speed of the gondola G, if the tact time is shortened (in other words, if the production volume is increased), the moving speed is necessarily increased. The distance in space from one point to the next inspection point must be long. That is, even if the sensor output suddenly changes in the defective portion D, the location (place) is “somewhere” between the two measurement points that have become long, and cannot be accurately identified. Here, when repairing a solar battery cell having the defect portion D in the repair process following the inspection step, the higher the positional accuracy of the defect portion D, the higher the accuracy of the electrode that applies the applied voltage to the defect portion D. If it can move toward, the defective portion can be burned out at a lower voltage. Therefore, when the tact time becomes fast, it is necessary to control the speed of the gondola G as follows.

  In the speed control of the gondola G, the drive unit 7 sets the drive speed based on a command from the processing unit 9. More specifically, in the speed control of the gondola G, when the gondola G moves in the downward direction indicated by the symbol M1 in FIG. 1, the moving speed is set to a relatively fast defect search speed. After the approximate position of the defective portion D as the short-circuit portion is found in the defect search of the defective portion D at this defect search speed, the gondola G is returned to the original position (home position) as indicated by reference numeral M2. . In this returned movement, until the section in which the defect portion D is detected, the movement is returned at the first speed that is faster than the defect search speed in the forward direction, and in the section in which the defect portion D is detected, it is sufficiently higher than the defect search speed. Driven at a low second speed. Thus, by appropriately setting the moving speed of the gondola G, the position resolution of the defective portion D can be improved, and as a result, the tact time can be improved.

[Second Embodiment]
FIG. 4 shows a defect inspection apparatus according to the second embodiment. The same parts and the same parts shown in FIG. 1 are denoted by the same reference numerals, and the description thereof can be omitted.

  The defect inspection apparatus according to the second embodiment will be described mainly focusing on differences from the first embodiment. In the second embodiment, the magnetic sensor Sj is arranged so as to exhibit magnetic sensitivity in the horizontal direction (x direction). In the first embodiment, the magnetic sensor Sj is arranged at the boundary of the cell Cj. In the second embodiment, for each cell Cj, the magnetic sensor Sj is substantially at the center of the cell Cj. It arrange | positions so that a part may be opposed.

  FIG. 5 shows the distribution of the horizontal magnetic field in the cell cross section along the line VV in FIG. According to the result of the simulation shown in FIG. 5, the horizontal component of the magnetic vector has a maximum value at approximately the center of the cell Cj. In this sensor position arrangement, the sensor output sign is reversed in the adjacent sensor Sn + 1, and the absolute value of the sensor output is almost the same. This means that the redundancy of the sensor Sj can be remarkably improved in the sensor arrangement in the second embodiment as compared to the first embodiment. That is, even if a certain sensor Sn fails, the adjacent sensor Sn + 1 can sufficiently compensate for the failure of the sensor Sn, and the probability of failing to detect the defective portion D can be greatly improved. In addition to redundancy, as will be described later, when the defective part D is continuous and there are defective parts in two adjacent cells, the presence of continuous cells in the defective part D is more positively detected. can do.

  In the second embodiment, the control unit 6 connected to the external power supply 4 does not need to be provided with a current detection function for detecting a current. This is because the probe Pj is normally pressed against the object to be contacted at a right angle, so that a magnetic field can be detected by the probe Pj when a current is supplied through the probe Pj. . If a current flows through the probe Pj, the magnetic field generated by the current draws a concentric circle centered on the probe Pj in the xy plane, and in the initial state where the gondola G is returned to the home position, Magnetic concentric circles are conveniently detected by a magnetic sensor Sj that is sensitive in the horizontal direction. This fact means that the magnetic sensor according to the second embodiment has exactly the same function as the current detection function of the first embodiment.

  In the second embodiment, as in the first embodiment, the moving speed of the gondola G is changed by moving the arrows M1 and M2 of the gondola G with respect to the measurement system converted into discrete data. The tact time can be improved.

  In the solar cell unit, there may be a defect in two cells Cj at the same time. Even in such a case, the present invention can be applied.

  FIG. 6 shows the relationship between the horizontal magnetic field detected by the sensor Sj and the cell position along the VV line when the defect portion D occurs in the adjacent cells Cn and Cn + 1 in the defect inspection apparatus shown in FIG. The graph obtained by the simulation shown is shown. FIG. 7 shows the horizontal magnetic field and VV line detected by the sensor Sj when there are defects in the two cells Cn and Cn + 2 arranged on both sides of the normal cell Cn + 1 in the defect inspection apparatus shown in FIG. The graph obtained by the simulation which shows the relationship with the cell position along is shown. In both graphs shown in FIGS. 6 and 7, the magnetic distribution in the defect inspection apparatus according to the first embodiment and the measured values actually output by the magnetic sensor Sj are indicated by rhombuses as described in the graph. Shown as dots. In order to simplify the description, it is assumed that the defect type of the defect portion D is a short-circuit type defect in any cell.

  In FIG. 6, if there is a defect in the continuous cells Cn and Cn + 1, the output amounts of the magnetic sensors Sn-1, Sn, Sn + 1, and Sn + 2 are arranged very characteristicly as indicated by the diamonds. Data other than the data indicated by the diamonds are not detected because the sensor Sj is not provided. When such characteristic array data is acquired, the adjacent cells Cn and Cn + 1 are defective. Here, since the sensor output from the magnetic sensors Sn and Sn + 1 arranged at the cell boundary shows a large positive value, the cells Cn and Cn + 1 located on the left side (left side of the cell boundary) of these magnetic sensors Sn and Sn + 1 A defect has occurred. Even if it cannot be determined that there are a plurality of defects from the data indicated by the rhombuses, the defect portion D is placed in one of the two cells Cn and Cn + 1 because of the relationship between the position coordinates of the gondola G and the position where the detected magnetism suddenly drops. It turns out that there is. This is because the probability that two defect positions are at the same y-coordinate position is very low, and therefore the position where the magnetism disappears is generally different in the two cells.

  FIG. 7 shows the distribution of cell position magnetism along the VV line and the sensor output value when a defect D occurs in the cell Cn and the cell Cn + 2 on both sides of one normal cell Cn + 1. As shown in FIG. 7, two peaks (the sensor outputs from the magnetic sensors Sn and Sn + 2 and corresponding to the peak output) are clearly provided for such a defect arrangement in which the defect portion D occurs. Appearing data is obtained in accordance with the case where there is only one defective part D. This means that there is a defect in the cells Cn and Cn + 2 arranged on the left side of the magnetic sensors Sn and Sn + 2 arranged at the cell boundary that generates a large positive output (peak output). Therefore, even in such a case, the defect portion D can be detected without overlooking the defect portion D.

  Next, in the case where there is a defective portion D in the adjacent cells Cn and Cn + 1 that are also continuous, and in the case where the two cells Cn and Cn + 2 on both sides of the normal cell Cn + 1 are defective in the middle of the cell arrangement, the second implementation A simulation result in the defect inspection apparatus having the arrangement of the magnetic sensor Sj according to the embodiment will be described with reference to FIGS.

  FIG. 8 shows the distribution of the horizontal magnetic field detected with respect to the cell position along the line V-V when the defect portion D occurs in the adjacent cells Cn and Cn + 1 in the defect inspection apparatus shown in FIG. ing. Further, FIG. 9 shows the defect inspecting apparatus shown in FIG. 4 with respect to the cell position along the VV line in the case where the defective portion D is generated in the cells Cn and Cn + 2 adjacent to both sides of a normal cell Cn + 1. It shows the distribution of the horizontal magnetic field detected. 8 and 9, sensor outputs from the magnetic sensors Sn, Sn + 1, and Sn + 2 arranged on the center of the cell are shown as points indicated by rhombuses.

  If the continuous cells Cn and Cn + 1 are defective as shown in FIG. 8, the output amounts of the magnetic sensors Sn, Sn + 1 and Sn + 2 are arranged in a very characteristic linear manner as shown by the points indicated by diamonds. The Other than the data indicated by the rhombuses, the sensor S is not provided and therefore is not detected. When this linear array data is acquired, the adjacent cells Cn and Cn + 1 are defective. Here, since the sensor output from the magnetic sensor Sn arranged on the cell Cn shows a large positive value, the cell Cn where the magnetic sensor Sn is located has a defect. Further, since the sensor output from the magnetic sensor Sn + 2 arranged on the cell Cn + 2 shows a large negative value, a defect has occurred in the cell Cn + 1 located on the left side (left side of the cell boundary) of the magnetic sensor Sn + 2. It becomes. Even if it cannot be determined that there is a defect from the data indicated by the rhombus, the defective portion D is in one of the two cells Cn and Cn + 1 because of the relationship between the position coordinates of the gondola G and the position where the detected magnetism suddenly rises or falls. It turns out. This is because the probability that two defect positions are at the same y-coordinate position is very low, and therefore the position where the magnetism disappears is generally different in the two cells.

  As shown in FIG. 9, three maximum values having different polarities are alternately detected from the outputs from the sensors Sn, Sn + 1, and Sn + 2 arranged at the center of the three cells Cn, Cn + 1, and Cn + 2 adjacent to each other. Therefore, the output characteristics from the sensors Sn, Sn + 1 and Sn + 2 shown in FIG. 9 are clearly distinguished from the characteristics shown in FIG. 5 and can be determined as an output when a single cell Cn has a defect. Is prevented. As is apparent from the outputs from the magnetic sensors Sn, Sn + 1 and Sn + 2 shown in FIG. 9 (distribution of outputs indicated by diamonds), the sensor outputs from the magnetic sensors Sn and Sn + 2 arranged on the cells Cn and Cn + 2 are positive. Since the value is large, the cells Cn and Cn + 2 where the magnetic sensors Sn and Sn + 2 are located are defective. Further, since the sensor outputs from the magnetic sensors Sn + 1 and Sn + 3 arranged on the cells Cn + 1 and Cn + 3 show a large negative value, the cells Cn + 1 and Sn + 3 located on the left side (left side of the cell boundary) of the magnetic sensors Sn + 1 and Sn + 3 A defect is generated in Cn + 3.

  In the example of the solar cell shown in FIG. 9, a large value with the same polarity appears across a large value with a different polarity, so this case is also clearly distinguished from the examples of FIGS. Further, as described above, since the point at which the sensor output value changes suddenly varies from cell to cell, the probability of overlooking the defective portion D is reduced. In the example of a solar cell in which two or more cells Cj in which normal cells are arranged in the middle are defective, the detected magnetic distribution is the magnetic distribution when only one cell Cj has a defect. There is no risk of overlooking the defect because it approaches the shape and there are simply a plurality of magnetic distribution shapes.

[Third Embodiment]
FIG. 10 schematically shows a solar cell defect inspection apparatus according to the third embodiment. Whether the type of magnetic sensor used as described above is a type that detects a magnetic component in the vertical direction or a type that detects a magnetic component in the horizontal direction, the type is basically the same. is there. Therefore, in order to simplify the description, the defect inspection apparatus shown in FIG. 10 according to the third embodiment uses a sensor Pj of a type that can detect a magnetic component in the horizontal direction. In FIG. 10, the first row of probes R1Pj to which a reverse voltage is applied are provided in the upper part of FIG. 10 as in the first and second embodiments. In addition to the first row of probes, a second row of probes R2Pj of the same type is provided in the lower part of FIG. Here, it should be noted that the probes R1Pj and R2Pj in the first and second rows are distinguished from each other by adding symbols R1 and R2 indicating that the probes belong to the first and second rows. As described in the first and second embodiments, the series circuit of the external power source 4-R1 and the control unit 6-R1 is connected between the probes R1Pn and R1Pn + 1 in the first row of probes R1Pj. A reverse voltage is applied to these probes R1Pn and R1Pn + 1. Similarly, a series circuit of the external power source 4-R2 and the control unit 6-R2 is connected between the probes Pn and Pn + 1 in the second row probe R2Pj, and a reverse voltage is applied to the probes R1Pn and R1Pn + 1.

According to such a defect inspection apparatus, in the cell Cn, the currents ₁ I and ₂ I flow toward the defect D as shown in FIG. Currents ₁ I and ₂ I flow in the opposite directions from the defective portion D of the current. Since the currents ₁ I and ₂ I flow in opposite directions, the polarity of the magnetic field created by these currents is reversed on both sides of the defect portion D as shown on the left side of FIG. As apparent from this output graph, the amount of change in the output of the magnetic field is larger than that in the second embodiment shown in FIG. 4, and the polarity of the magnetic field is inverted in the longitudinal direction of the cell. ing. Here, the magnitudes of these two theoretical output values are different depending on whether the defective portion D is in any position in the y direction, but the absolute value of the output change amount as the difference is almost constant. Will be maintained. Therefore, in the third embodiment, even if a lower voltage is applied from the probe, not only is there an advantage that a defect can be found, but even if the size of the solar cell is increased, the upper and lower regions Since the reverse voltage is applied from these two points, there is an advantage that a sufficiently large current value, in other words, generation of a sufficiently large magnetic field can be expected while reducing the level of the reverse voltage. This can be said to be a more technically advantageous effect nowadays when solar cells are aimed at increasing size.

  According to the third embodiment, as shown in FIG. 11, when two short-circuit defects D1 and D2 are generated in the same cell Cj, the magnetic field characteristics as shown on the left side of FIG. Therefore, the sudden change locations of the characteristic values appear as defect positions D1 and D2, and the probability of finding the defect portions D1 and D2 can be improved. This third embodiment suggests that there is a strong correlation between the number of probe arrays R and the discovery of a plurality of defective portions D in the same cell. Since this correlation will be described in detail later, refer to the description.

  In the third embodiment, a sensor Sj having sensitivity to a horizontal magnetic field is used as in the second embodiment 2 shown in FIG. 4, but the sensor Sj is not limited to such a sensor Sj. As in the first embodiment, a sensor Sj having sensitivity in the vertical direction may be provided on the boundary line of the cell Cj.

[Fourth Embodiment]
FIG. 12A shows a defect inspection apparatus according to the fourth embodiment of the present invention. In this apparatus, a sensor Pj sensitive to a horizontal magnetic field is arranged opposite to the center of the cell Cj. In the fourth embodiment, as shown in FIG. 12B, a voltage V in which an alternating current component [Vp-p] is superimposed on a direct current component Vdc is applied between the cells Cj, and the alternating current component applied from the magnetic sensor signal [ Only the same frequency component as Vp−p] is extracted and the magnetic quantity is measured. The reverse voltage applied to the cell needs to not exceed the reverse withstand voltage of the cell Cj at the peak of alternating current. Further, it is desirable to prevent a forward voltage from being applied to the cell Cj at the reverse peak of the alternating current. When these relationships are expressed by equations,
DC voltage [Vdc] + AC voltage [Vp−p] ÷ 2 ≦ cell reverse withstand voltage DC voltage [Vdc] ≧ AC voltage [Vp−p] / 2
It becomes.

  As described with reference to FIG. 2B in the first embodiment by exemplifying the constant current drooping characteristic, the current flowing through the cell Cj and the voltage are set to a predetermined value or less, and an excessive current is applied to the cell. It is necessary to prevent an excessive voltage from flowing to Cj and being applied to the cell Cj, and this is the same in the fourth embodiment. However, in the fourth embodiment, if the voltage or current is limited, the AC waveform may be distorted and an accurate magnetic quantity may not be obtained. Therefore, it is necessary to avoid exceeding the voltage and current limits at the peak of alternating current.

  Assuming that such a constraint is satisfied, if a larger alternating current is applied, the signal becomes larger with respect to noise, and the S / N ratio can be improved and the defect position can be found more accurately. On the other hand, if priority is given to reducing the damage to the solar cell, it is desirable that the applied direct current and alternating current are smaller, so it is preferable to select an appropriate applied level in consideration of these.

  Next, the frequency of the AC component applied to the cell Cj will be described.

  If the frequency f0 of the alternating current component is too high, the alternating current value differs between a location near and far from the probe Pj due to the capacitance between the cells Cj and the resistance of the surface electrode of the cell Cj, which is not preferable. On the other hand, if the frequency f0 is too low, it takes much time for noise removal by averaging. As an example of satisfying these contradictory conditions, a high-frequency cutoff frequency: fc = 1 / (2πCR) is obtained from the capacitance C0 between the cells Cj and the resistance R between both ends of the cell. On the other hand, a sufficiently low frequency f0, for example, a frequency f0 which is about one tenth, can be used as a selection criterion. Actually, the capacity C0 between the cells Cj is not a lumped constant, but is generated in a distributed constant between the cells Cj, and the actual high frequency cutoff frequency fc is also different. However, here, since the purpose is to know the standard of the frequency f0, this difference is not a problem. For example, when the resistance R from end to end of the cell Cj is 1 kΩ and the capacitance C0 between the cells Cj is 1000 pF, the high-frequency cutoff frequency fc is about 159 kHz. Therefore, as an example, the frequency f0 can be selected with the tenth of about 15.9 kHz as a guide. The frequency f0 is preferably a frequency different from the noise component from the surroundings and its harmonic component so that the noise can be effectively removed.

  In the fourth embodiment, as shown by a block 32 in FIG. 12C, a voltage including an AC component and a DC component as shown in FIG. 12B is generated from the external power source 32 and applied to the cell Cj of the solar cell 2. The In the solar cell 2, as indicated by a block 34, an alternating magnetic field generated by a current flowing through the cell Cj is detected by the magnetic sensor Sj, and a magnetic signal H (Sj) including an AC component is output. From this magnetic sensor signal H (Sj), only the AC frequency component f0 supplied and applied to the AC signal processing unit 36 is extracted as a defect detection signal. From the magnetic signal H (Sj), noise components and the like from the surroundings can be removed to generate a defect detection signal, and the influence of the noise components and the like can be further reduced by time averaging. As a result, a more accurate magnetic quantity can be detected by the signal processing shown in FIG. 12C.

  In the AC signal processing unit 36, in order to extract only the AC frequency component applied from the magnetic sensor signal H (Sj), the size of the AC frequency component extracted using a bandpass filter or a resonance circuit is also included. Can be output. For example, the extracted alternating current may be rectified and smoothed and output as a direct current, or the extracted alternating current may be A / D converted and its size can be known by calculation. The magnetic sensor signal H (Sj) is given to a digital oscilloscope, and the averaging function or the voltage value output function can be used to detect the magnitude of the magnetic sensor signal H (Sj). If synchronous detection, quadrature detection, or Fourier transform (including FFT) is used, phase information can be obtained in addition to amplitude information, which can be used for more accurate defect position specification. In addition, a frequency characteristic analyzer (FRA), a lock-in amplifier, a box car integrator, and the like are commercially available as electronic measuring instruments that realize functions such as synchronous detection and Fourier transform, and averaging functions. In particular, since the lock-in amplifier can extract a minute signal buried in noise, a particularly preferable result can be obtained when the magnetic sensor output is small. For this reason, the applied voltage level can be lowered further, and the possibility of damaging the surface of the solar cell can be lowered. Therefore, the effect of improving the yield in the manufacturing process can also be expected.

  For example, when FRA is used as the AC signal processing unit 36, the output of the FRA oscillation unit combined with a DC bias is applied to the solar cell 2 as it is or through an amplifier, and the output of the magnetic sensor Sj is output to the FRA. To the analysis input section. In FRA, the frequency component of the oscillation part of the signal given to the analysis input part can be extracted by Fourier transform, and its magnitude and phase can be known. Furthermore, averaging can be performed as necessary.

  When a lock-in amplifier is used as the AC signal processing unit 36, an alternating current applied from an external power source is given to the reference signal of the lock-in amplifier, and an output of the magnetic sensor is given to the input unit of the lock-in amplifier. The lock-in amplifier can detect the phase and the phase of the frequency component of the reference signal by detecting the phase of the signal given to the input unit using the reference signal. Furthermore, averaging can be performed as necessary to improve the signal-noise ratio (S / N ratio).

  As described in the first, second, and third embodiments, when only DC is applied, a commercial frequency of 50 Hz may be mixed into the magnetic sensor signal H (Sj) as a noise component from the surroundings. is there. In such a case, in order to reduce this influence, it is necessary to average at least one period of 50 Hz = 20 ms or more. Furthermore, it takes 200 ms to average the 10 cycles to further reduce the influence of noise. On the other hand, when, for example, 15.9 kHz is used as described above, the frequency components other than this are removed, so the 50 Hz component is also removed. Therefore, an averaging time of at least 15.9 kHz and one period≈0.063 ms is sufficient, and even when averaging is performed for 10 periods, an averaging time of 0.63 ms is sufficient. Therefore, the measurement time can be greatly shortened compared with the case where only DC is applied. In addition, when averaging for the same time as when only DC is applied, the influence of noise can be reduced to a higher degree.

  Further, as described in the first, second and third embodiments, when only DC is used, it is necessary to use a magnetic sensor capable of detecting a DC magnetic field. Alternatively, an MI sensor is used.

  On the other hand, when a bias AC voltage (DC + AC) is used as in the fourth embodiment, it is only necessary to detect an AC magnetic field. Therefore, a fluxgate sensor or a simple coil may be used as a sensor. it can. Furthermore, if a capacitor is provided in parallel with the coil and the resonance frequency is adjusted to the frequency to be extracted, unnecessary frequency components can be removed even in the sensor Sj, so that the measurement circuit can be simplified and the measurement time can be shortened, and more accurate. Defect position detection becomes possible.

[Fifth Embodiment]
As is clear from the above description, even though a sensor group is mounted on a movable gondola to detect “continuously” magnetism, in reality it is based on “discrete data”. Has been detected. On the other hand, FIG. 13A shows a defect inspection apparatus according to the fifth embodiment in which necessary spatial resolution is given in advance on the assumption that discrete data is handled. A defect inspection apparatus according to the fifth embodiment will be described with reference to FIG. 13A.

  In the defect inspection apparatus according to the fifth embodiment, in particular, it is difficult to make repair work compatible with defect detection and defect position specification within a predetermined tact time when the production amount of solar cells increases. It is effective in the case. In the fifth embodiment, a large number of magnetic sensors Sj are not moved in the xy plane, but are fixedly arranged at regular intervals in the xy plane. Since the magnetic sensor Sj is fixed, the probe Pj for applying the reverse voltage does not need to be placed at the end of the solar cell panel, and can be placed at an optimum place for detecting a defect.

  FIG. 13A shows a plan view of the solar cell 2 as seen from the back side as already described. In the solar cell 2, a plurality of striped cells Cn extending in the y direction are provided, as in the above-described embodiment. Are arranged. The first probe row R1Pj and the second probe row R2Pj indicated by the white circle marks are arranged on the solar cell 2 with an interval as shown in FIG. 13A, and the remaining space has a horizontal direction indicated by a rectangle. Magnetic sensors Sj sensitive to magnetism are arranged in a matrix. More specifically, the magnetic sensor Sj has a cell pitch in which the cells Cj are arranged in the first direction (the arrangement direction of the cells Cj) and detects defects in the second direction (the extending direction of the cells Cj). The sensor pitches (predetermined intervals) having a correlation with the resolution are arranged in a matrix. A mark indicated by a solid triangle indicates the location of the probe Pj to which a reverse voltage is applied during repair in the next process. FIG. 13A should illustrate only the arrangement of the sensors Sj and the like necessary for inspecting defects in the defect inspection process, but a triangle is provided to facilitate understanding of the repair description in the next repair apparatus. The solid mark is attached to FIG. 13A.

  In FIG. 13A, the distance between the two probe rows R1Pj and R2Pj is divided into two equal parts to be one distance y0. Using the distance y0 as a unit, the longitudinal direction (y direction) of the cell Cj is equally divided into four sections. In the following description, the four regions D1, D2, D3, and D4 are referred to as first, second, third, and fourth divided regions along the longitudinal direction. In each of the divided areas D1, D2, D3, and D4, two magnetic sensors Sj are basically arranged as indicated by rectangular marks.

  However, an extra magnetic sensor Si is disposed between the second and third divided regions D2 and D3.

  The magnetic sensors Sj, Si and the probe rows R1Pj, R2Pj are naturally installed not on the solar cell 2 side but on the device side, and the solar cell panel 2 is conveyed to the device as shown in FIG. 13A. The magnetic sensors Sj and Si and the probe rows R1Pj and R2Pj are designed to be disposed in a relative positional relationship.

  It is assumed that one defect D is generated as shown in FIG. 13B in the solar cell panel 2 carried into the apparatus designed as described above. Also in FIG. 13B, the positions where the repair probes RP1 and RP2 are to be arranged are indicated by black triangle marks. This triangular mark indicates the position where the repair probes RP1 and RP2 should be arranged in the manufacturing apparatus for the next repair process. In the inspection process, the repair probes RP1 and RP2 are not actually arranged. Please note that.

  When a reverse voltage is applied from the probe Pj with the second probe array R2Pj, current flows toward the defective portion D, so that the sensor outputs H1 and H2 from the sensors Sj1 and Sj1 are output at substantially the same level. The sensor outputs H3 and H4 from the sensors Sj3 and Sj4 are output at zero level. Only with these levels of data, the position of the defect D is determined to be between the sensors Sj2 and Sj3 and between the sensors Sj1 and Sj4. According to these levels of data, it is determined that there may be two defects D even though only one defect D actually occurs.

  In the next repair process, current in the reverse direction is supplied from the burnout probes RP1 and RP2 arranged at the positions indicated by black triangle marks, and the defect D is repaired. In this repair process, of the two repair probes RP1 and RP2, the triangular mark probe RP1 with an underline has the same function as the inspection probe Pj indicated by a white circle, thereby reducing the cost of the apparatus. In terms of meaning, it corresponds to a completely useless probe. In the repair device, this is omitted, and while remaining in the defect inspection process, a reverse voltage is applied by the probe RP1 between the sensors Sj1 and Sj4. Even if it exists, it is preferable to complete the repair work. From this viewpoint of cost reduction, referring to FIG. 13A again, it can be seen that the repair probe RP closest to the two probe rows R1Pj and R2Pj is underlined with black triangle marks. These indicate that the probe can be omitted when designing the repair device. Here, the repair probes in the repair process are arranged in a matrix form from the beginning. It is not an absolute condition, but is composed of a small number of probe groups configured to be movable to the positions shown in the figure. Also note that it is good. Further, in the repair process, a reverse voltage is applied from the repair probes RP1 and RP2 to the defective portion D to be repaired while gradually increasing, and a current is supplied so that no current flows in the reverse direction. In order to realize the repair in such a repair process, it is preferable that the repair probes RP1 and RP2 include a reverse voltage booster circuit (not shown) in which the voltage is gradually boosted. It is obvious that this booster circuit may be configured similarly to the detection circuit unit 5 shown in FIG.

  In the case of the sensor arrangement shown in FIG. 13A, the resolution in specifying the defect position is calculated as follows. Since the length of the cell Cj in the y direction is 4 × y0 and the number of magnetic sensors Sj per cell is 9, the sensor intervals D1, D2, D3, and D4 are 4 × y0 ÷ 9. It turns out that it is. For example, in the solar cell 2 with 4 × y0 of 1400 mm, it is 156 mm. If the probe position in the repair process is set at the center of the sensor interval, the maximum value of the distance from the defect portion and the repair probe RP to the defect D is 156/2 = 78 mm. This distance corresponds to a sufficiently practical distance. If it is desired to further reduce the maximum distance at the time of repair from this distance, three test probe rows may be prepared and designed with the same design concept. In this case, since the number of magnetic sensors Sj is further increased by five, the number of sensors is 14, and the distance between the sensors is 1400 ÷ 14 = 100 mm, and the maximum distance between the probe and the defect in the repair device is , 100 ÷ 2 = 50 mm. The maximum distance is a number when it is maximized, and is actually lower than this, so it can be determined that the specification is sufficient. Needless to say, the repair to which the reverse voltage is applied in the repair process need not be all probes, but only probes in the section where the detected defect exists.

  FIG. 14 shows a manufacturing apparatus provided with a defect inspection section according to the embodiment of the present invention. FIG. 14 shows a schematic arrangement in a vertical inner cross section along the conveying direction of the solar cell panel 2. In FIG. 14, it is assumed that the longitudinal direction of the cell Cj is also directed in the left-right direction in FIG. When the solar battery panel 2 is carried into the manufacturing apparatus by the transport roller 44 and the solar battery panel 2 is stopped at the position indicated by the one-dot chain line by the positioning means (not shown), the lift pneumatic cylinder 46 The solar cell panel 2 is lifted to the height indicated by the solid line. This lift amount is such a height that the solar cell panel 2 that is in a positional relationship so that the inspection probe Pn does not contact the cell Cj is lifted and the probe Pn contacts the cell Cj with a normal contact pressure. Is set. At the same time, the height of the magnetic sensor is determined to be a predetermined height from the position of the lifted panel. In this state, the defect is inspected and the position thereof is identified. After this operation is completed, the lift pneumatic cylinder 46 is actuated again and lowered to the position indicated by the one-dot chain line. Sent to the repair device. With this configuration, the magnetic sensors Sj arranged in a matrix need not be changed in relative position, and can be designed at a fixed position with respect to the manufacturing apparatus.

  As an embodiment suitable for a manufacturing apparatus that targets a production amount at a level that is likely to be within a predetermined tact time including repair until the production amount of the solar cell is not extremely large, FIG. 15A to FIG. There is a manufacturing apparatus according to the fifth embodiment.

  15A and 15B, unlike the arrangement shown in FIGS. 13A and 13B, the magnetic sensor Sj is arranged on the lower side of the panel 2 as indicated by a dotted line. Probe rows R1Pj and R2Pj used for reverse voltage application and repair are mounted on movable gondola G1 and G2, and have a structure so that the gondola G1 and G2 can be driven up and down with respect to the paper surface of FIG. 15A by a motor. Yes. The probe rows R1Pj and R2Pj and the gondola G1 and G2 on which the probe rows R1Pj and R2Pj are placed may basically be one set, but here two sets are prepared in order to give versatility to the description. In this example, the gondola G1 uses the divided areas D1 and D2 as moving areas, and the gondola G2 uses the divided areas D3 and D4 as moving areas.

[Sixth Embodiment]
FIG. 16 shows the arrangement of each part when the manufacturing apparatus according to the sixth embodiment is viewed in the vertical cross section. Also in FIG. 16, the case where the longitudinal direction of the cell C and the conveyance direction of a panel correspond is illustrated. In FIG. 16, the magnetic sensor Sj is mounted on a lift plate (not shown) that lifts the panel 2 in contact with the output rod of the lift pneumatic cylinder 46. Here, when the panel 2 is lifted, it is lifted together without changing the distance between the lift plate and the panel 2. With this structure, the magnetic sensor Sj can occupy a place as close to the panel surface as possible, and the defect detection sensitivity can be maintained high.

  The sixth embodiment is different from the fifth embodiment in that the transparent substrate 12 made of a slightly thick glass plate or transparent resin is between the sensor Sj and the cell electrode. As the distance increases, the sensitivity decreases as the distance increases, but the sensitivity of the entire system is improved by the application of the present invention, and the voltage value of the applied reverse voltage is slightly reduced. It is possible to deal with it sufficiently. According to the sixth embodiment, since the probe Pj and the sensor groups R1Sj and R2Sj do not physically interfere with each other, the probe Pj can be moved, and immediately after the position of the defect is specified, The probe Pj can be moved to and the repair work can be started. That is, it is possible to obtain an economic effect that it is not necessary to separately provide a repair manufacturing apparatus. Therefore, the sixth embodiment is suitable when a predetermined tact time can be taken relatively long.

  In the first to fourth embodiments, an example is described in which defects are detected by arranging the sensors Sj by the number of cells and moving the sensors Sj in the longitudinal direction of the cells Cj. In the fifth and sixth embodiments with reference to FIGS. 13A to 16, a configuration is shown in which the sensors Sj are arranged in a matrix in the vertical and horizontal directions and the sensors Sj are not moved. As a contrast between these configurations, a defect inspection may be performed by moving a smaller number of sensors vertically and horizontally. Further, the defect inspection may be performed by arranging the sensors Cj in the cell longitudinal direction and laterally moving each cell.

[Seventh Embodiment]
When the sensor Sj is moved in the longitudinal direction of the cell and a defect is detected as in the first to fourth embodiments, the cell Cj and the sensor Sj are caused by the deflection of the cell Cj or the distortion of the rail of the gondola G. May change, and the output of the sensor Sj may also change. For this reason, a change in sensor output may lead to erroneous detection of defect detection.

  As shown in FIGS. 13A and 15A, when the sensors Sj are arranged in a matrix in the vertical and horizontal directions, a defect may be erroneously detected in the same manner due to a sensitivity error between the sensors Sj or variations in the output offset voltage.

  In order to solve such a problem, as shown in FIGS. 17A to 17C, a constant current Ipre1, Ipre2, Ipre3 is supplied in the longitudinal direction of the cell from the power sources Vpre, Vpre2, Vpre3 to move the sensor Sj or It is preferable to calibrate the variation between the sensors Sj in advance. With this calibration, at the time of actual defect inspection, accurate measurement can be performed by reversely correcting the sensitivity and the like of the magnetic sensor Sj based on the calibration result. In this calibration, based on a calibration command from the processing unit 9, the detection circuit unit 5 including the power sources Vpre, Vpre2, and Vpre3 supplies constant currents Ipre1, Ipre2, and Ipre3 to the cell Cj through the probe, and the magnetic sensor This can be realized by measuring magnetism with Sj.

  As described above in detail, according to the present invention, the number of probes in contact with the solar cell can be significantly reduced, and the external power supply voltage applied via the probes can be set low. Therefore, the probability of damaging the solar cell can be reduced. In particular, according to the third and fourth embodiments, this applied voltage can be further reduced.

  First, if there is no cell through which a current flows when a reverse voltage is applied to the cell, it is possible to skip the subsequent work and move to the next process, and build an efficient production line. You can also.

  According to the present invention, if there is a short-circuit defect, the output of at least two magnetic sensors can be used, and even if a failure occurs in the detection sensor, the defect is not detected. It is possible to prevent a situation in which a product flows into the next process, and to realize a manufacturing apparatus with excellent quality control.

  Further, even when there is only one cell Cj through which a current flows or only a few cells, the location of the short-circuit defect can be accurately identified, so that the repair probe can be placed near the short-circuit location, and therefore at the time of repair. A sufficient current that can be repaired can be passed even if the voltage of the current is lowered. That is, there is an advantage that repair is easy and repair can be completed early. Here, although the repair itself was not touched, a method of causing an excessive current to flow in the reverse direction and burning the defective part to convert it into an electrical insulator as in the prior art can be used. In order to flow the reverse current, for example, the probe array shown in FIG. 1 is integrally configured so as to be movable in the y direction, and is driven by a motor or the like so that the probe pj comes to the target location, so that the current flows. What is necessary is just to comprise. Apart from the probes illustrated in the first and second embodiments, a repair-specific probe row may be fixed to the gondola so that it can be moved to the short-circuit position, or the cell is transported to another manufacturing apparatus. Repair work may be performed.

  Furthermore, although the magnetic sensor illustrated here has sensitivity in the vertical direction or the horizontal direction, it is not necessary to be limited to this. In the magnetic sensor, the sum of the vertical magnetic vector and the horizontal magnetic vector are vectorized to obtain the original magnetic vector direction and magnitude. You may change so that it may have sensitivity. In this case, it is desirable to set the magnetic vector to be the largest at a specific position in the cell width direction (x direction), and to install a sensor near the maximum position.

  Furthermore, according to the embodiment of the present invention, a voltage in which an alternating current is superimposed on a direct current is applied between the cells, and only the frequency component of the applied alternating current can be extracted and used from the magnetic sensor. With such a configuration, a high-speed and noise-resistant measurement system can be constructed. In this embodiment, the inspection device can be realized even with a lower applied voltage, and the generation of scratches in the manufacturing process of the solar cell as a product can be suppressed low.

  Moreover, according to this embodiment, since a simple coil can be used as a magnetic sensor, an increase in cost can be suppressed even when a plurality of magnetic sensors are used. Furthermore, by forming a resonance circuit by connecting a capacitor in parallel to this coil, it is possible to extract only the applied AC frequency component, and therefore the measurement circuit and the like can be simplified.

  2. . . Solar cell, 4, 4-R1, 4-R2. . . External power supply, 5, 5-R1, 5-R2. . . Detection circuit section, 6, 6-R1, 6-R2. . . Control unit, Cj, Cn, Cn + 1. . . Solar cell, 12. . . Transparent substrate, 14. . . Surface electrode, 16. . . Amorphous silicon (thin film silicon), 18. . . Back electrode, D.D. . . Defect or defective part, Pj, Pn, Pn + 1. . . Probe, Sj, Sn, Sn + 1. . . Magnetic sensors, G.M. . . Gondola, 36. . . AC signal processor

Claims (21)

A solar cell in which a large number of solar cells are arranged in parallel along a substantially first direction on an insulating substrate, and each solar cell is along a substantially second direction perpendicular to the first direction. In the extended solar cell defect inspection system,
First voltage applying means for applying a first voltage in a direction opposite to the forward voltage to the solar cells adjacent to each other;
A magnetic field that detects the strength of the magnetic field generated by the current flowing along the second direction of the solar cell in association with the application of the first voltage in the reverse direction in association with the position along the second direction. Detection means;
Based on the output distribution of the strength of the magnetic field associated with the position along the second direction, the presence or absence of an electrical defect occurring in the solar battery cell and the location of the defect in the defect A defect location specifying means for specifying a location;
A defect inspection apparatus for a solar cell, comprising: When the generated magnetic field is decomposed into a first magnetic field component along a third direction substantially orthogonal to a plane including the first and second directions and a second magnetic field component along the first direction,
The solar cell defect inspection apparatus according to claim 1, wherein the magnetic field detection unit is arranged to detect at least one of the first and second magnetic field components.     The magnetic field detection unit includes a magnetic sensor unit that detects the strength of the magnetic field, and a movement unit that includes a position detection unit that moves the magnetic sensor unit along the second direction and detects a movement position associated with the movement. The defect inspection apparatus of the solar cell of Claim 1 or Claim 2 characterized by comprising.     The said moving means is set to the speed selected from the several moving speed according to the command from the outside, and moves the said magnetic sensor along the said 2nd direction, It is characterized by the above-mentioned. Solar cell defect inspection equipment.     The magnetic field detection unit includes a plurality of magnetic sensor units arranged at predetermined intervals along the second direction, and the defect position specifying unit is configured to output the defect from the outputs of the plurality of magnetic sensor units. The solar cell defect inspection apparatus according to claim 1, wherein the position of the solar cell is specified.     The voltage application means includes a power supply unit that applies a voltage obtained by superimposing an AC voltage having a certain AC frequency on a DC voltage corresponding to the first voltage in the reverse direction to the adjacent solar cells, 6. The solar cell defect inspection apparatus according to claim 1, wherein the magnetic field detection means includes extraction means for extracting the AC frequency component from the output signal.     The solar cell defect inspection apparatus according to claim 6, wherein the extraction unit is any one of a resonance circuit unit, a bandpass filter unit, a synchronous detection circuit unit, a quadrature detection circuit unit, and a Fourier transform circuit.     The magnetic field detection means includes any one of a Hall element sensor, an MI sensor, a sensor including a coil, a sensor including a resonance circuit including a coil and a capacitor, or a fluxgate sensor. The defect inspection apparatus of the solar cell of Claims 1-6.     9. The sun according to claim 1, further comprising a calibration unit that applies a predetermined current to the solar battery cell and executes a calibration process for correcting an error factor of the magnetic field detection unit. Battery defect inspection device. The voltage applying means includes
In addition to the first voltage applying means for applying the first voltage in the reverse direction to the one end region of the solar cell, the forward voltage is applied to the other end region of the solar cells adjacent to each other. A second voltage applying unit configured to apply a second voltage in the reverse direction, wherein the magnetic field detecting unit determines the strength of the magnetic field generated by the current flowing in the region between the one end region and the other end region; The solar cell defect inspection apparatus according to claim 1, wherein detection is performed in association with positions along two directions.     The voltage application means includes a voltage application section that applies the first voltage and a conveyance means that conveys the voltage application section along the second direction, or a place specified by the defect position specification means or this place The voltage application unit is transported to a region including the voltage, and a reverse voltage boosting unit capable of boosting the voltage until the current no longer flows in the reverse direction by applying the voltage in the reverse direction while gradually increasing is provided. The solar cell defect inspection apparatus according to claim 1.   The manufacturing apparatus of a solar cell provided with the defect inspection apparatus of Claims 1-11. A solar cell in which a large number of solar cells are arranged in parallel along a substantially first direction on an insulating substrate, and each solar cell is along a substantially second direction perpendicular to the first direction. In the extended solar cell defect inspection method,
A first voltage application step of applying a first voltage in a direction opposite to the forward voltage to the solar cells adjacent to each other;
A magnetic field that detects the strength of the magnetic field generated by the current flowing along the second direction of the solar cell in association with the application of the first voltage in the reverse direction in association with the position along the second direction. A detection process;
Based on the output distribution of the strength of the magnetic field associated with the position along the second direction, the presence or absence of an electrical defect occurring in the solar battery cell and the location of the defect in the defect A defect location identifying step for identifying the location;
A defect inspection method for a solar cell, comprising:     The defect position detecting step includes a magnetic field distribution detecting step for associating a change in the magnetic field distribution with a position along the second direction, and the second direction in which the change in the magnetic field distribution is greater than or equal to a predetermined magnitude. The method for inspecting a defect of a solar cell according to claim 13, further comprising the step of specifying a spot or area as the defect position.     15. The defect position detecting step includes a step of examining a strength of a magnetic field associated with a moving position while moving a magnetic field sensor along the second direction. Inspection method for solar cells.     In the defect position detection step, a region in which a defect is generated is determined by roughly examining the strength of the magnetic field while moving at a relatively high speed, and based on the result of this step, the region with a low suspicion of the defect is The step of passing the magnetic sensor at a high speed at a first speed and checking the high-accuracy region while moving the magnetic sensor relatively slowly at a second speed slower than the first speed. Item 15. A method for inspecting defects of a solar cell according to Item 15.     The defect position detecting step includes a step of substantially simultaneously checking a magnetic field at a plurality of locations with a plurality of sensors along the second direction, and further including a step of identifying a region where a defect exists from these magnetic field data. 15. The method for inspecting defects of a solar cell according to claim 13 or 14, characterized by comprising:     The voltage applying step includes a step of applying a voltage on which an alternating voltage having an alternating frequency at a direct current voltage corresponding to the first voltage in the reverse direction is superimposed on the adjacent solar cells, and detecting the magnetic field 18. The solar cell defect inspection method according to claim 13, wherein the means further includes a step of extracting the AC frequency component from the output signal. The voltage application step includes
What is the forward voltage in the other end region of the solar cells adjacent to each other in addition to the first voltage application step of applying the first voltage in the reverse direction to the one end region of the solar cell? A second voltage application step of applying a second voltage in the reverse direction, wherein the magnetic field detection step determines the strength of the magnetic field generated by the current flowing in the region between the one end region and the other end region. The solar cell defect inspection method according to claim 13, wherein the detection is performed in association with a position along two directions.     The voltage applying step includes a transporting step that is performed while transporting the voltage applying unit that applies the first voltage along the second direction, and the portion specified in the defect position specifying step or the region including this portion. The method further includes the step of conveying the voltage application unit and applying the voltage in the reverse direction while gradually increasing the voltage until the current stops flowing in the reverse direction. The defect inspection method according to claim 13.     The manufacturing method of the solar cell containing the defect inspection method of Claims 13-19.

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