Abnormality determination system and method for solar cell module

Abstract

An abnormality determination system of a solar cell module according to the present application is for determining whether an abnormality exists in each of a plurality of solar cell units that constitute a solar cell module and are connected in series. The abnormality determination system controls an irradiation state of incident light on a solar cell unit to be determined to be at least a first irradiation state and a second irradiation state in which a short-circuit current of the solar cell unit to be determined is larger than in the first irradiation state, irradiates the solar cell unit to be determined with modulation light different from the incident light, detects a slight change in an output current of the solar cell module that occurs with the modulation light irradiating the solar cell unit to be determined, and outputs the detection result as a phase detection unit. A ratio between the phase detection unit output in the first irradiation state and the phase detection unit output in the second irradiation state is calculated, and the ratio calculated by a ratio calculation unit is compared with a threshold value set in advance.

Description

Technical Field

[0001] This invention relates to an anomaly detection system and a method for solar cell modules. This application claims priority to Japanese Patent Application No. 2020-216691, filed on December 25, 2020, the entire contents of which are incorporated herein by reference. Background Technology

[0002] To date, an anomaly detection system and method for solar cell modules are known, which can accurately determine which of a series-connected solar cell unit is in an abnormal state (see Patent Document 1). Furthermore, conventionally, when one of the multiple solar cell units constituting a solar cell module is partially shaded, modulated light is irradiated onto that solar cell unit, while simultaneously detecting minute changes in the output current of the solar cell module. A known solar cell operating voltage estimation system is used to detect minute changes in the output current of a solar cell module, and, while that solar cell unit is partially shaded, modulated light is irradiated onto the other solar cell units respectively (see Patent Document 2). Existing technical documents Patent documents

[0003] Patent Document 1: Patent No. 6712816 Patent Document 2: International Publication No. 2020 / 122105 Summary of the Invention The problem that the invention aims to solve

[0004] The inventors believe that, as a condition for effectively utilizing the technology described in Patent Document 2, it is important that the solar cell units constituting the solar cell module have the same degree of parallel resistance. Therefore, before measuring the voltage of the multi-technology-based solar cell unit described in Patent Document 2, it is necessary to evaluate the parallel resistance of each solar cell unit. Therefore, the purpose of this invention is to provide an anomaly determination system and a method for anomaly determination of a solar cell module. This system can determine whether the parallel resistance component of the series-connected solar cell units within a solar cell module is abnormal. Problem-solving methods

[0005] One aspect of the present invention is an anomaly determination system for a solar cell module, used to determine whether each of a plurality of solar cell units constituting a solar cell module and connected in series is abnormal, comprising: an irradiation state control unit, which controls the irradiation state of the incident light on the solar cell unit to be determined to at least a first irradiation state and a second irradiation state, wherein the second irradiation state is a state in which the short-circuit current of the solar cell unit to be determined is greater than that of the first irradiation state; a modulated light irradiation unit, which irradiates the solar cell unit to be determined with modulated light different from the incident light; a phase detection unit, which detects minute changes in the output current of the solar cell module caused by the modulated light irradiating the solar cell unit to be determined, and outputs the detection result as a phase detection unit output; a ratio calculation unit, which calculates the ratio between the output of the phase detection unit in the first irradiation state and the output of the phase detection unit in the second irradiation state; and a comparison unit, which compares the ratio calculated by the ratio calculation unit with a preset threshold.

[0006] In an anomaly detection system for a solar cell module according to one aspect of the present invention, the first irradiation state is a state in which the incident light irradiating the solar cell cell to be determined is controlled to decrease, and the second irradiation state is a state in which the incident light irradiating the solar cell cell to be determined is controlled to increase.

[0007] In an anomaly detection system for a solar cell module according to one aspect of the present invention, the first irradiation state is a state in which neither control for reducing the incident light irradiating the solar cell cell to be determined is performed, nor control for increasing the incident light irradiating the solar cell cell to be determined is performed; the second irradiation state is a state in which control is performed to increase the incident light irradiating the solar cell cell to be determined.

[0008] In an anomaly detection system for a solar cell module according to one aspect of the present invention, the first irradiation state is a state in which control is performed to reduce the incident light irradiating the solar cell cell to be determined; the second irradiation state is either a state in which control is not performed to reduce the incident light irradiating the solar cell cell to be determined, or a state in which control is performed to increase the incident light irradiating the solar cell cell to be determined.

[0009] One aspect of the present invention is a method for determining anomalies in a solar cell module, used to determine whether each of a plurality of solar cell units constituting a solar cell module and connected in series is abnormal. The method includes: an illumination state control step, controlling the illumination state of incident light on a solar cell unit to be determined to at least a first illumination state and a second illumination state, wherein the second illumination state is a state in which the short-circuit current of the solar cell unit to be determined is greater than that of the first illumination state; a modulated light illumination step, illuminating the solar cell unit to be determined with modulated light different from the incident light; a phase detection step, detecting minute changes in the output current of the solar cell module caused by the modulation light illuminating the solar cell unit to be determined, and outputting the detection result as a phase detection unit output; a ratio calculation step, calculating the ratio between the output of the phase detection unit in the first illumination state and the output of the phase detection unit in the second illumination state; and a comparison step, comparing the ratio calculated by the ratio calculation unit with a preset threshold.

[0010] In a method for determining anomalies in a solar cell module according to one aspect of the present invention, the modulation illumination step includes: a first illumination state modulation illumination step, wherein when controlled to be the first illumination state, the modulation light is irradiated onto the solar cell unit to be determined; a second illumination state modulation illumination step, wherein when controlled to be the second illumination state, the modulation light is irradiated onto the solar cell unit to be determined; and a phase detection step includes: a first illumination state phase detection step, wherein when controlled to be the first illumination state, the detection result of a minute change in the output current of the solar cell module caused by the modulation light irradiating the solar cell unit to be determined is output as a phase detection unit output for the first illumination state; and a second illumination state phase detection step, wherein when controlled to be the second illumination state, the detection result of a minute change in the output current of the solar cell module caused by the modulation light irradiating the solar cell unit to be determined is output as a phase detection unit output for the second illumination state. The effects of the invention

[0011] According to the present invention, an anomaly determination system and a method for anomaly determination of a solar cell module are provided, which can determine whether the parallel resistance component of the solar cell units connected in series in the solar cell module is abnormal. Attached Figure Description

[0012] [ Figure 1 [Figure 10 in Patent Document 1] is the figure corresponding to Figure 10 in Patent Document 1. [ Figure 2 [] indicates that it is used for explanation Figure 1 An example diagram of the IV curves illustrating the qualitative principle of the operation of a solar cell unit. [ Figure 3 [Illustration 1] is a diagram representing the equivalent circuit of a solar cell module consisting of m solar cell units. [ Figure 4 [R] is a constant in the equivalent circuit of a real solar cell unit, which makes the parallel resistance component R of "Unit 1" equal to... sh1 When the change occurs, the ratio of "Unit 1" (△I) phi / Σ△I phi The figure shows the numerical simulation results of the voltage dependence of ). [ Figure 5 [This is a diagram illustrating the operating voltage of a normal solar cell obtained by applying mask dimming and light enhancement to a normal solar cell with high parallel resistance in a solar cell module.] [ Figure 6 [This is a diagram illustrating the operating voltage of a defective solar cell obtained by applying mask dimming and light enhancement to a defective (abnormal) solar cell with low parallel resistance in a solar cell module.] [ Figure 7 [ ] is an example diagram of the structure of the anomaly detection system for a solar cell module according to the first embodiment. [ Figure 8 [ ] is a flowchart illustrating an example of the processing performed in the anomaly detection system of the solar cell module according to the first embodiment. [ Figure 9 [Illustration 1] is a diagram showing the structure of the experimental apparatus in the embodiment. Specific Implementation

[0013] Before describing embodiments of the anomaly determination system and method for solar cell modules of the present invention, the operating principle of the anomaly determination system for solar cell modules of the present invention will be explained.

[0014] Figure 1 It is the figure corresponding to Figure 10 in Patent Document 1. exist Figure 1 In the system shown, a weakly modulated light ML is applied to only one solar cell C3 within the generating solar cell module M, ensuring that the operating voltage of solar cell C3 remains constant. The synchronization signal of the modulated light ML is minimally mixed into the output current of the solar cell module M, depending on the operating voltage of solar cell C3. Therefore, by using a non-electrically contactable AC current clamp sensor and a lock-in amplifier in the wiring connected to the solar cell module M, the minimal synchronization signal mixed into the output current of the solar cell module M can be extracted.

[0015] Figure 2 It indicates that it is used for explanation. Figure 1This is an example diagram of the IV curves illustrating the qualitative principle of the operation of a solar cell unit. In detail, Figure 2 This is related to Kobayashi, Kanesu, "Proposal on a Non-Contact Unit Voltage Detection Line Utilizing Unit Voltage within a Modulated Optical Module," IEEE Transactions on Electrical Engineering, Vol. 140, No. 1, pp. 14-24 (2020). Figure 1 The corresponding diagram. In Figure 2 In the middle, the horizontal axis represents solar cell unit C3 (see...). Figure 1 The vertical axis represents the operating voltage of the solar cell module M (see [reference]). Figure 1 The output current of ). like Figure 2 As shown, as the operating voltage of solar cell unit C3 decreases, the absolute value of the negative voltage increases ( Figure 2 (Left side), the smaller the slope of the IV curve. When the modulated light ML illuminating the solar cell unit C3 generates a current with a constant amplitude ( Figure 2 China and Israel "△I ph When (indicated by ""), the voltage change within solar cell unit C3 is proportional to the reciprocal of the slope of the IV curve ( Figure 2 The Chinese use "Large△v" i "and "Small△v i (This indicates that) the amplitude of the synchronization signal for modulated light increases. As the voltage change within solar cell unit C3 increases, the small change ΔI in the output current of solar cell module M also increases, and the operating voltage of solar cell unit C3 can be estimated based on the amplitude of the synchronization signal extracted by the lock-in amplifier.

[0016] Figure 2 The slope of the IV curve shown corresponds to the differential resistance of solar cell unit C3, and the lock-in amplifier output ΔI ph The magnitude of ΔI is proportional to the differential resistance of solar cell unit C3. Therefore, in the technology described in Patent Document 2, in order to quantitatively estimate the module voltage (operating voltage of solar cell units C1 to C5) within the solar cell module M, when modulated light is irradiated onto each of all solar cell units C1 to C5, the lock-in amplifier outputs ΔI. ph The lock-in amplifier output ΔI when a solar cell cell i (any one of solar cell cells C1 to C5) is illuminated with modulated light, whose unit voltage (operating voltage) is to be estimated. phi The lock-in amplifier output ΔI when modulated light is irradiated onto all solar cell units C1 to C5 respectively ph The sum (Σ△I phi ) ratio (△I phi / Σ△I phi ). Compared to (△I) phi / Σ△I phi If the value of ) is small, it is inferred that the unit voltage (operating voltage) of solar cell unit i is relatively large. This ratio (△I) phi / Σ△I phi Alternatively, the differential resistors of each solar cell unit C1 to C5 can be used to replace the lock-in amplifier output ΔI. ph To represent. If the constants of the equivalent circuit of each solar cell unit C1 to C5 are determined beforehand, then the ratio (ΔI) of the voltages of any cell unit (the operating voltage of any one of the solar cell units C1 to C5) is... phi / Σ△I phi The value of ) can be obtained through numerical simulation. Therefore, in the present inventors Kobayashi and Kinsu, "Proposal on a Non-Contact Unit Voltage Detection Line Utilizing Unit Voltage in a Modulated Optical Module", Electrical Engineering Society Papers B, Vol. 140, No. 1, pp. 14-24 (2020), based on the parallel resistance component contained in the equivalent circuit of a solar cell unit ( Figure 3 The Chinese use "R" sh1 “R” sh2 "Indicates) comparison (△I phi / Σ△I phi The impact of ) has been verified.

[0017] Figure 3 This is a diagram showing the equivalent circuit of a solar cell module composed of m solar cell units. In detail, Figure 3 This is equivalent to Kobayashi and Kanesu's "Proposal on a Non-Contact Unit Voltage Detection Line Utilizing Unit Voltage within a Modulated Optical Module," IEEE Transactions on Electrical Engineering, Vol. 140, No. 1, pp. 14-24 (2020). Figure 3 (a). In Figure 3 In the diagram, the solar cell unit on the left is referred to as "Unit 1", and the remaining solar cell units ((m-1) solar cell units) are combined into "Unit 2", which is represented by a single solar cell unit. This assumption is clearly not without generality. Figure 4 In the constants of the equivalent circuit of a real solar cell unit, the parallel resistance component R of "Unit 1" is... sh1 When the change occurs, the ratio of "Unit 1" (△I) phi / Σ△I phi The figure shows the numerical simulation results of the voltage dependence of the voltage. In detail, Figure 4 This is from Kobayashi and Kanesu's "Proposal on a Non-Contact Unit Voltage Detection Line Utilizing Unit Voltage within a Modulated Optical Module," published in the Journal of the Electrical Engineering Society, Vol. 140, No. 1, pp. 14-24 (2020). Figure 7.exist Figure 4 In the middle, the vertical axis is the ratio (△I) phi / Σ△I phi The horizontal axis represents the unit voltage. exist Figure 4 In the numerical simulation shown, the parallel resistance component R sh1 =R sh2 =2.3kΩ is the standard. The result is as follows: Figure 4 As shown, in the parallel resistance component R sh1 Less than the standard parallel resistance component R sh2 In the case of (=2.3kΩ), even if the voltage v1 of "Unit 1" is the same, it is possible to reduce the voltage by (△I) to 2.3kΩ. phi / Σ△I phi The value of ) is less than the parallel resistance component R. sh1 Equal to the standard parallel resistance component R sh2 The value of the ratio when (=2.3kΩ). Conversely, in the parallel resistance component R sh1 The component R greater than the standard parallel resistance sh2 With (=2.3kΩ), the voltage v1 of "Unit 1" is near 0V, compared to (△I phi / Σ△I phi The value of ) saturates to 1. That is, the parallel resistance component of the solar cell unit to be determined has an influence ratio (ΔI) phi / Σ△I phi The tendency of the value of ). Therefore, as described above, as a condition for effectively utilizing the technology described in Patent Document 2, the inventors believe that it is important that the solar cell units constituting the solar cell module have the same degree of parallel resistance. Before measuring the voltage of the multi-technology-based solar cell unit described in Patent Document 2, it is necessary to evaluate the parallel resistance of each solar cell unit.

[0018] A review of aging phenomena in actual solar cell modules reveals that they originate from Potential Induced Degradation (PID) in the high-voltage battery module and current leakage defects in the solar cell units caused by manufacturing defects, leading to a decrease in the parallel resistance of the solar cell units. PID, as a cause of aging under normal long-term use of solar cell modules, has attracted attention. Electro-Luminescence (EL) testing, which involves separating the testing module from the wiring and injecting current into a dark box to observe the luminescence distribution, has been put into practical use as a method for detecting aging caused by PID. However, using the EL method requires stopping the solar cell module's power generation, which places a significant burden on the inspection process. Therefore, alternative methods are desired to improve this situation.

[0019] Therefore, the inventors estimate the parallel resistance components of each solar cell unit C1 to C5 within the solar cell module M by utilizing the measurement signal (output signal) ΔI of the phase detection unit (lock-in amplifier) ​​used in the technology described in Patent Document 1 and the technology described in Patent Document 2.

[0020] [principle] In the abnormality determination system and method of the solar cell module of the present invention, the technology described in Patent Document 1 and Patent Document 2 are the same. While the solar cell unit of the test object (specifically, the test object for whether the parallel resistance component is abnormal) in the solar cell module M is irradiated with modulated light, the phase detection unit (lock-in amplifier) ​​extracts the signal from the solar cell unit of the test object that is synchronized with the modulated light from the output signal of the solar cell module M. The novel method performed in the anomaly determination system and method for solar cell modules of the present invention is to partially block the incident light on the solar cell cell to be measured (e.g., by attaching a mask to the solar cell cell to be measured to reduce the incident light irradiating the solar cell cell to be measured (mask light reduction) etc.) and to partially enhance the incident light on the solar cell cell to be measured (e.g., by irradiating the solar cell cell to be measured with stable light such as a lamp to increase the incident light irradiating the solar cell cell to be measured (light enhancement) etc.) to change the operating voltage of the solar cell cell to be measured. When mask subtraction is applied to the solar cell unit of the test object, the short-circuit current I of the solar cell unit of the test object is higher than that before mask subtraction is applied. sc As the IV curve decreases, it appears in the negative direction of the vertical axis. Figure 5 and Figure 6 The downward movement is parallel to the upward movement. Conversely, if the light enhancement is applied to the solar cell unit being measured, the short-circuit current I of the solar cell unit being measured is lower than before the light enhancement was applied. sc As the IV curve increases, it moves in the positive direction of the vertical axis ( Figure 5 and Figure 6 (Upward) moves parallel to the top.

[0021] Figure 5 This diagram illustrates the operating voltage of a normal solar cell obtained by applying masking and photo-enhancing techniques to a normal solar cell with high parallel resistance in a solar cell module. Figure 5In the diagram, within a solar cell module M composed of m solar cell units, "Unit 1" represents the solar cell unit (a normal solar cell unit) that is the subject of the measurement. Figure 5 In the diagram, the horizontal axis represents the operating voltage v1 of "Unit 1", and the vertical axis represents the output current I of the solar cell module M. Since the solar cell module M connects all the solar cell units in series, every solar cell unit, including Unit 1, flows with the same output current I. The operating voltage V of solar cell module M m The operating voltage v1 of "Unit 1" at that time can be determined according to... Figure 5 The operating method shown is roughly estimated as follows: For simplicity, the open voltage of each solar cell unit (the open voltage of "Unit 1" in the normal state (without mask dimming or light enhancement)) is set to v. oc .

[0022] When mask dimming is applied to a normal solar cell unit (“cell 1”) with high parallel resistance, the IV curve becomes... Figure 5 The image shows "reduced I by masking". sc The curve for "(short-circuit current)" in Unit 1. The operating voltage v1 of "Unit 1" is determined by... Figure 5 The "reduction of I through mask" shown sc The intersection of the curve of Unit 1 and the composite curve of m-1 units in the module is represented. That is, the working voltage v1 of Unit 1 is represented by the following equation (1). In addition, as Figure 5 As shown, at this intersection point, "I is reduced by the mask". sc The slope of the curve for "Unit 1" is nearly horizontal (i.e., the slope is approximately zero). The differential resistance of "Unit 1" is equivalent to the reciprocal of its slope, which is very large. The value of the vertical axis at the intersection point represents the reduction in I due to the mask. sc ".

[0023] [Formula 1]

[0024] When photo-enhancing is applied to a normal solar cell unit (“Unit 1”) with a high parallel resistance component, the IV curve becomes... Figure 5 The image shows "increased I through light" sc The curve for "(short-circuit current)" in Unit 1. The operating voltage v1 of "Unit 1" is determined by... Figure 5 The image shows "increased I through light" sc The curve of unit 1 (short-circuit current) and the intersection of the curve of the composite of m-1 units in the module are represented. That is, the operating voltage v1 of "unit 1" is represented by the following equation (2). In addition, as Figure 5As shown, at the intersection, "the light transmission increased I". sc The slope of the curve for "Unit 1" is very large. The differential resistance of "Unit 1" is equivalent to the reciprocal of its slope, which is very small. The vertical axis value at the intersection of the composite curve of "m-1 units in the module" and the vertical axis (where the operating voltage v1 of "Unit 1" is zero) represents the "maskless I". sc "I was increased by light." sc The vertical axis value of the horizontal portion of the curve for unit 1 (short-circuit current) represents the increase in I through light. sc ".

[0025] [Formula 2]

[0026] like Figure 5 As shown, the ratio r of the differential resistance (very large) of "cell 1" when the mask light is reduced to the differential resistance (very small) of "cell 1" when the light is increased is very large. Due to the operating voltage V of solar cell module M m The operating voltage v1 of "cell 1" can be easily estimated by applying mask dimming and light enhancement to "cell 1" as described above.

[0027] Figure 6 This is a diagram illustrating the operating voltage of a defective solar cell obtained by applying mask dimming and light enhancement to a defective (abnormal) solar cell cell with low parallel resistance in a solar cell module. exist Figure 6 In the diagram, within a solar cell module M composed of m solar cell units, "Unit 1" represents the solar cell unit (a defective solar cell unit) being measured. Figure 6 In the diagram, the horizontal axis represents the operating voltage v1 of "Unit 1", and the vertical axis represents the output current I of the solar cell module M. Since the solar cell module M connects all the solar cell units in series, every solar cell unit, including Unit 1, flows with the same output current I. When the operating voltage V of solar cell module M m At that time, the operating voltage v1 of "Unit 1" can be determined according to Figure 6 The operation method shown is roughly estimated as follows.

[0028] When mask dimming is applied to a defective solar cell unit (“cell 1”) with low parallel resistance, the IV curve becomes... Figure 6 The image shows "reduced I by masking". sc The curve for "(short-circuit current)" in Unit 1. The operating voltage v1 of "Unit 1" is determined by... Figure 6 The image shows "reduced I by masking". sc The intersection of the curve of Unit 1 and the composite curve of m-1 units in the module is represented. That is, the working voltage v1 of Unit 1 is represented by the following equation (3). In addition, as Figure 6 As shown, at their intersection, "I is reduced by the mask". sc The slope of the curve for "Unit 1" is greater than zero. The differential resistance of "Unit 1" is very small, equivalent to the reciprocal of its slope. The value of the vertical axis at the intersection of the "synthetic curve of m-1 units in the module" and the vertical axis (where the working voltage v1 of "unit 1" is zero) represents the "maskless I". sc "Because the mask reduces I..." sc The value of the vertical axis at the intersection of the "(short-circuit current) Unit 1 curve" and the vertical axis (where the operating voltage v1 of "Unit 1" is zero) represents "the reduction of I through the mask". sc ".

[0029] [Formula 3] v1>v m -(m 1)v oc (3)

[0030] When photo-enhancing is applied to a poor solar cell unit (“Unit 1”) with low parallel resistance, the IV curve becomes... Figure 6 The image shows "increased I through light" sc The curve for "(short-circuit current)" in Unit 1. The operating voltage v1 of "Unit 1" is determined by... Figure 6 The image shows "increased I through light" sc The intersection of the curve of Unit 1 and the composite curve of m-1 units in the module is represented. That is, the working voltage v1 of Unit 1 is represented by the following equation (4). In addition, as Figure 6 As shown, at this intersection, "the amount of light passing through increases by I". sc The slope of the curve of unit 1 is greater than zero, which is consistent with the above-mentioned "through mask I". sc The intersection of the curve of reduced unit 1 and the composite curve of m-1 units within the module, "through mask I" sc The slope of the curve for "reduced unit 1" is the same. The differential resistance of "unit 1" is very small, equivalent to the reciprocal of its slope. That is, when optical enhancement is applied to a defective "cell 1" with low parallel resistance, the differential resistance of "cell 1" is the same as that of "cell 1" when mask subtraction is applied to "cell 1". "I was increased by light" sc The vertical axis value at the intersection of the curve of Unit 1 and the vertical axis (where the operating voltage v1 of Unit 1 is zero) represents the increase in I through light.sc ".

[0031] [Formula 4] v1 < v oc (4)

[0032] like Figure 6 As shown, the ratio r of the differential resistance (small) of "cell 1" when the mask light is reduced to the differential resistance (small) of "cell 1" when the light is increased is approximately "1". Even in poor solar cell units with low parallel resistance, the operating voltage of solar cell units using mask dimming and light enhancement will change, but the range of operating voltage variation is smaller compared to normal solar cell units with high parallel resistance.

[0033] Therefore, in order to estimate whether the parallel resistance component of each of the multiple series-connected solar cell units in the solar cell module M is normal or lower than normal and therefore defective (abnormal), the inventors have discovered that it is sufficient to determine whether the ratio r of the differential resistance of the solar cell unit when mask dimming is used to the differential resistance of the solar cell unit when light enhancement is applied is above a predetermined threshold. In addition, in order to confirm whether the value of the ratio r of the differential resistance of a solar cell when mask dimming is applied to the differential resistance of a solar cell when light enhancement is applied is above a predetermined threshold, the inventors use the ratio of the output of a phase detection unit (e.g., the output of a lock-in amplifier) ​​when mask dimming is applied to a solar cell with an anomaly to be determined to be above a certain threshold to the output of a phase detection unit (e.g., the output of a lock-in amplifier) ​​when light enhancement is applied to a solar cell with an anomaly to be determined to be above a certain threshold. In other words, by comparing the value of the phase detection unit output (e.g., the output of a lock-in amplifier) ​​when, for example, mask dimming is applied to a solar cell cell where the presence or absence of anomalies is to be determined, with the value of the phase detection unit output (e.g., the output of a lock-in amplifier) ​​when, for example, light dimming is applied to a solar cell cell where the presence or absence of anomalies is to be determined, with a preset threshold, we found that it is possible to estimate whether the parallel resistance component of each of the multiple solar cell cells connected in series in the solar cell module M is normal or below normal (abnormal).

[0034] [First Embodiment] In the following, embodiments of the anomaly determination system and method for solar cell modules according to the present invention will be described. Figure 7This is an example diagram of the structure of the anomaly detection system 1 for the solar cell module M according to the first embodiment. exist Figure 7 In the example shown, the anomaly detection system 1 of the solar cell module M in the first embodiment is applied to the solar cell module M. The solar cell module M consists of multiple solar cell units C1, C2, C3, C4, and C5 connected in series. The solar cell module M is connected to the load resistor RL. exist Figure 7 In the example shown, the solar cell module M consists of 5 solar cell units C1, C2, C3, C4, and C5. In another example, the solar cell module M can consist of any number (M units, where M is an integer greater than 2) of solar cell units other than the 5 units connected in series.

[0035] exist Figure 7 In the example shown, the anomaly detection system 1 of the solar cell module M can determine whether the parallel resistance component of each of the solar cell units C1, C2, C3, C4, and C5 is abnormal. The anomaly detection system 1 of the solar cell module M includes an illumination state control unit 1A, a modulated light illumination unit 11, a phase detection unit 12, an AC clamp sensor 13, and a determination unit 1B. The irradiation status control unit 1A determines whether the incident light affects the parallel resistance of the solar cell unit (in...). Figure 7 In the example shown, the irradiation state of the solar cell unit C3 is controlled to at least a first irradiation state and a second irradiation state in which the short-circuit current of the solar cell unit C3 is greater than that of the first irradiation state. In detail, the illumination state control unit 1A sets the illumination state of the solar cell C3 by configuring (e.g., attaching) a mask on a portion of the light-receiving surface of the solar cell C3 (i.e., by applying a mask to block light) the incident light onto the solar cell C3. That is, the first illumination state is a state in which the incident light irradiating the solar cell C3 (where the presence or absence of abnormalities in the parallel resistance component is to be determined) is reduced. Furthermore, the illumination state control unit 1A sets the illumination state of the solar cell unit C3 to a second illumination state by irradiating the light-receiving surface of the solar cell unit C3 with light other than sunlight (e.g., the illumination light of an LED lamp) (i.e., by applying light enhancement). That is, the second illumination state is a state in which the incident light irradiating the solar cell unit C3, whose parallel resistance component needs to be determined, is increased.

[0036] In another example, the illumination state control unit 1A can also set the illumination state of the solar cell C3 to the first illumination state by attaching a mesh (not shown) to a portion of the light-receiving surface of the solar cell C3, where the presence or absence of abnormalities in the parallel resistance component is to be determined. Furthermore, in other examples, the illumination state control unit 1A can also set the illumination state of the solar cell unit C3 to the first illumination state by configuring a light-shielding object (not shown) that blocks sunlight from illuminating the light-receiving surface of the solar cell unit C3, where the abnormality of the parallel resistance component needs to be determined.

[0037] In other examples, the illumination state control unit 1A may also set the illumination state of the solar cell unit C3 to a second illumination state by irradiating the solar cell unit C3 with illumination light from a light source other than an LED lamp (e.g., a laser).

[0038] exist Figure 7 In the example shown, the modulation light irradiation unit 11 irradiates the light-receiving surface of the solar cell C3, whose parallel resistance composition is to be determined, with a modulation light ML that is different from the incident light (i.e., sunlight and the irradiation light from LED lamps, etc.). The modulation light irradiation unit 11 includes a laser irradiation unit 111, an optical chopper 112, an ultra-high-speed control unit 113, a reflector 114, and a filter 115. The laser irradiation unit 111 irradiates a laser, such as a He-Ne laser. exist Figure 7 In the example shown, as described above, the modulated light illumination unit 11 includes a laser illumination unit 111. However, in other examples, the modulated light illumination unit 11 may also include an illumination unit for illuminating light other than a laser.

[0039] exist Figure 7 In the example shown, optical chopper 112 modulates the laser emitted from laser irradiation unit 111 into modulated light ML with a specified phase (frequency). Ultrasonic control unit 113 controls optical chopper 112. Additionally, ultrasonic control unit 113 outputs a reference signal RS representing the phase (frequency) of the modulated light ML modulated by optical chopper 112. Filter 115 attenuates the modulated light ML modulated by optical chopper 112. Filter 115 is, for example, a Neutral Density (ND) filter. Reflector 114 reflects the modulated light ML attenuated by filter 115. The modulated light ML reflected by reflector 114 irradiates solar cell C3, where the presence or absence of abnormalities in the parallel resistance component needs to be determined. exist Figure 7In the example shown, the modulated light ML reflected by reflector 114 illuminates solar cell cell C3. In other examples, the modulated light ML reflected by reflector 114 may also illuminate any one of the solar cell cells C1, C2, C4, and C5 other than solar cell cell C3 (where the presence or absence of abnormalities in the parallel resistance component of the solar cell cell is to be determined). exist Figure 7 In the example shown, the optical chopper 112, filter 115, and reflector 114 are arranged in the order of optical chopper 112, filter 115, and reflector 114 between the laser irradiation unit 111 and the solar cell module M. In another example, alternatively, the order of optical chopper 112, filter 115, and reflector 114 may be different.

[0040] exist Figure 7 In the example shown, the phase detection unit 12 detects minute changes in the output current of the solar cell module M as the modulated light ML illuminates the solar cell cell C3, thereby determining whether the parallel resistance component of the solar cell cell C3 is abnormal. Furthermore, the phase detection unit 12 outputs its detection result. The phase detection unit 12 includes a lock-in amplifier 12a. Lock-in amplifier 12a is connected to AC clamp sensor 13, which is not in contact with the wiring connected to solar cell module M. That is, phase detection unit 12 detects minute changes in the output current of solar cell module M via AC clamp sensor 13 and lock-in amplifier 12a. The reference signal RS output from the ultrasonic control unit 113 is input to the lock-in amplifier 12a. That is, the reference signal RS input to the lock-in amplifier 12a represents the phase (frequency) of the modulated light ML irradiated from the modulated light irradiation unit 11 onto the solar cell unit C3, whose parallel resistance component is to be determined as to be abnormal. The output of the lock-in amplifier 12a (phase detection unit output) represents the detection result of a small change in the output current of the solar cell module M, which is determined to be a solar cell cell C3 with an abnormality in the parallel resistance component irradiated by the modulated light ML.

[0041] The determination unit 1B determines whether the parallel resistance component of the solar cell unit C3 to be determined is abnormal. The determination unit 1B includes a phase detection output acquisition unit 1B1, a ratio calculation unit 1B2, and a comparison unit 1B3. The phase detection output acquisition unit 1B1 acquires the phase detection unit output (output of the lock-in amplifier 12a). Specifically, when the irradiation state control unit 1A controls the irradiation state of the solar cell C3, for which the abnormality of the incident light on the parallel resistance component needs to be determined, to a first irradiation state, the phase detection output acquisition unit 1B1 acquires the phase detection unit output (output of the lock-in amplifier 12a) of the first irradiation state. Furthermore, when the irradiation state control unit 1A controls the irradiation state of the solar cell C3, for which the abnormality of the incident light on the parallel resistance component needs to be determined, to a second irradiation state, the phase detection output acquisition unit 1B1 acquires the phase detection unit output (output of the lock-in amplifier 12a) of the second irradiation state. The ratio calculation unit 1B2 calculates the ratio between the phase detection unit output (output of lock-in amplifier 12a) of the first irradiation state and the phase detection unit output (output of lock-in amplifier 12a) of the second irradiation state, which is obtained by the phase detection output acquisition unit 1B1. The comparison unit 1B3 compares the ratio of the phase detection unit output (output of the lock-in amplifier 12a) in the first irradiation state calculated by the ratio calculation unit 1B2 with the phase detection unit output (output of the lock-in amplifier 12a) in the second irradiation state and a preset threshold.

[0042] When the ratio of the output of the phase detection unit (output of lock-in amplifier 12a) in the first irradiation state to the output of the phase detection unit (output of lock-in amplifier 12a) in the second irradiation state is equal to or greater than a preset threshold, the determination unit 1B determines that the solar cell C3 to be determined does not have an abnormality of parallel resistance component (i.e., it determines that the parallel resistance component of the solar cell C3 to be determined is normal). On the other hand, when the ratio between the output of the phase detection unit (output of lock-in amplifier 12a) in the first irradiation state and the output of the phase detection unit (output of lock-in amplifier 12a) in the second irradiation state is less than a preset threshold, the determination unit 1B determines that the solar cell C3 to be determined has an abnormality of parallel resistance component (specifically, it determines that the parallel resistance component of the solar cell C3 to be determined is abnormally low).

[0043] In order for the phase detection output acquisition unit 1B1 to properly acquire the phase detection unit output (output of lock-in amplifier 12a) under the first irradiation state, for a normal solar cell unit, Figure 5 The image shows "reduced I by masking". sc The intersection of the curve of unit 1 and the composite curve of m-1 units in the module must be located in the part of the composite curve of m-1 units in the module with a large slope. That is, a mask with a sufficiently large area is required for mask subtraction (mask shading).

[0044] Furthermore, in order for the phase detection output acquisition unit 1B1 to properly acquire the phase detection unit output (output of the lock-in amplifier 12a) under the second illumination state, in Figure 5 and Figure 6 The image shows "increased I through light" sc In the curve of unit 1, the portion with a slope of zero relative to the composite curve of m-1 units in the module, and most of the portions with small slopes or approximately zero slopes, need to be located on the positive side of the vertical axis. Figure 5 and Figure 6 (The upper side). That is, Figure 5 and Figure 6 The "I increased by light" shown sc "Must be greater than "unmasked I" sc ". The irradiation status control unit 1A can first determine whether there are any abnormalities in the parallel resistance components of the incident light on the solar cell unit (in Figure 7 In the example shown, the irradiation state of the solar cell unit C3 is controlled as either the first irradiation state or the second irradiation state, where the irradiation state of the solar cell unit is controlled to determine whether there is any abnormality in the parallel resistance component of the incident light.

[0045] The solar cell module, which sets the threshold for comparison by the comparison unit 1B3, is composed of multiple solar cell units with normal parallel resistance components, as confirmed by another method (e.g., the EL method described above). This threshold is preset using a solar cell module containing abnormal solar cell units with low parallel resistance components.

[0046] In order to make the irradiation state of the solar cell unit C3, which is to be determined whether there are any abnormalities in the parallel resistance components of the incident light, become the second irradiation state, the light other than sunlight (such as the irradiation light of an LED lamp) used by the irradiation state control unit 1A must have a wavelength that can be absorbed by the solar cell unit C3 and output as a power generation current.

[0047] In one example of the anomaly detection system 1 for the solar cell module M in the first embodiment, the light irradiated by the irradiation state control unit 1A is the stable light of the LED lamp in order to make the irradiation state of the solar cell unit C3 by the incident light a second irradiation state. In other examples of the anomaly detection system 1 for the solar cell module M in the first embodiment, the light irradiated by the irradiation state control unit 1A is not stable light, but can be modulated light, in order to make the irradiation state of the solar cell unit C3 by the incident light a second irradiation state. However, the phase (frequency) of the modulated light is set to a value different from the phase (frequency) of the modulated light ML irradiated by the modulated light irradiation unit 11.

[0048] To make the illumination state of the incident light on the solar cell unit C3 a second illumination state, the illumination area and the illumination intensity per unit area of ​​the light irradiated by the illumination state control unit 1A are set as follows: Figure 5 and Figure 6 The "increased I through light" shown sc "Compared to "maskless I" sc "big.

[0049] In the example of the anomaly detection system 1 for the solar cell module M according to the first embodiment, the light irradiated by the illumination state control unit 1A is used to change the state of incident light irradiating the solar cell cell C3 to a second illumination state. The directionality of the light irradiated by the illumination state control unit 1A is set to not irradiate cells C1, C2, C4, and C5. Specifically, a laser is used as the light irradiated by the illumination state control unit 1A.

[0050] In another example of the anomaly detection system 1 of the solar cell module M in the first embodiment, in order to make the irradiation state of the solar cell cell C3 by the incident light a second irradiation state, the light irradiated by the irradiation state control unit 1A can also irradiate any one of the other solar cell cells C1, C2, C4, and C5. Even if the light irradiated by the irradiation state control unit 1A irradiates any one of the other solar cell cells C1, C2, C4, and C5 (i.e., leakage irradiation to any one of the other solar cell cells C1, C2, C4, and C5), the short-circuit current I of the solar cell cell C3 generated by the irradiation of the light from the irradiation state control unit 1A... sc The increase is greater than the increase in the short-circuit current I of each of the solar cell units C1, C2, C4, and C5 generated by the irradiation of the irradiation control unit 1A. sc The increase is large. According to the anomaly determination system 1 of the solar cell module M in the first embodiment, it can determine whether the parallel resistance component of the solar cell unit C3 is abnormal.

[0051] Figure 8 This is a flowchart illustrating an example of the processing performed in the anomaly detection system 1 of the solar cell module M according to the first embodiment. exist Figure 8 In the example shown, in step S1A1, the illumination state control unit 1A controls the illumination state of the incident light on the solar cell cell (e.g., solar cell cell C3) to be determined to have an abnormality in the parallel resistance component to be set to a first illumination state. For example, the illumination state control unit 1A sets the illumination state of the incident light on the solar cell cell C3 to the first illumination state by configuring a mask on a portion of the light-receiving surface of the solar cell cell C3. Next, in step S11A, when the irradiation state of the incident light on the solar cell unit C3, which is to be determined whether there is any abnormality in the parallel resistance component, is controlled by the irradiation state control unit 1A to be in the first irradiation state (for example, when the mask is disposed on part of the light-receiving surface of the solar cell unit C3), the modulation light irradiation unit 11 irradiates the light-receiving surface of the solar cell unit C3 with modulation light ML. Next, in step S12A, the phase detection unit 12 detects the minute changes in the output current of the solar cell module M as the modulated light ML irradiates the solar cell unit C3 in the first irradiation state. Then, the phase detection unit 12 outputs its detection result as the phase detection unit output for the first irradiation state. Next, in step S1B11, the phase detection output acquisition unit 1B1 acquires the phase detection unit output (output of lock-in amplifier 12a) of the first illumination state output by the phase detection unit 12 in step S12A.

[0052] Furthermore, in step S1A2, the illumination state control unit 1A controls the illumination state of the solar cell unit C3, whose condition regarding whether the incident light affects the parallel resistance component needs to be determined, to a second illumination state, i.e., a state where the short-circuit current of the solar cell unit C3 is greater than that of the first illumination state. For example, the illumination state control unit 1A illuminates the light-receiving surface of the solar cell unit C3 with modulated light ML and light different from sunlight (e.g., the illumination light from an LED lamp), thus making the incident light illumination state of the solar cell unit C3 the second illumination state. Next, in step S11B, when the irradiation state of the incident light on the solar cell unit C3, which is to be determined whether there is any abnormality in the parallel resistance component, is controlled by the irradiation state control unit 1A to be in the second irradiation state (for example, when the irradiation light of the LED lamp is irradiated onto the light-receiving surface of the solar cell unit C3), the modulation light irradiation unit 11 irradiates the light-receiving surface of the solar cell unit C3 with modulation light ML. Next, in step S12B, the phase detection unit 12 detects the minute changes in the output current of the solar cell module M as the modulated light ML illuminates the solar cell unit C3 under the second illumination state. Then, the phase detection unit 12 outputs its detection result as the phase detection unit output for the second illumination state. Next, in step S1B12, the phase detection output acquisition unit 1B1 acquires the phase detection unit output (output of lock-in amplifier 12a) of the second illumination state output by the phase detection unit 12 in step S12B.

[0053] Next, in step S1B2, the ratio calculation unit 1B2 calculates the ratio of the phase detection unit output (output of lock-in amplifier 12a) of the first irradiation state obtained in step S1B11 to the phase detection unit output (output of lock-in amplifier 12a) of the second irradiation state obtained in step S1B12. Next, in step S1B3, the comparison unit 1B3 compares the ratio of the phase detection unit output (output of lock-in amplifier 12a) in the first irradiation state to the phase detection unit output (output of lock-in amplifier 12a) in the second irradiation state calculated in step S1B2 with a preset threshold. If the ratio of the output of the phase detection unit in the first irradiation state (output of the lock-in amplifier 12a) to the output of the phase detection unit in the second irradiation state (output of the lock-in amplifier 12a) is above a preset threshold, the determination unit 1B determines that the solar cell C3 to be determined is abnormal because it does not have a parallel resistance component. If the ratio of the output of the phase detection unit in the first irradiation state (output of the lock-in amplifier 12a) to the output of the phase detection unit in the second irradiation state (output of the lock-in amplifier 12a) is less than a preset threshold, the solar cell C3 to be determined is determined to be abnormal because it has a parallel resistance component.

[0054] As described above, according to the anomaly judgment system 1 of the solar cell module M in the first embodiment, it is possible to determine whether the parallel resistance components of the series-connected solar cell units C1, C2, C3, C4, and C5 in the solar cell module M are abnormal.

[0055] [Second Embodiment] The following describes a second embodiment of the anomaly determination system and anomaly determination method for a solar cell module according to the present invention. The anomaly detection system 1 of the solar cell module M in the second embodiment is configured in the same way as the anomaly detection system 1 of the solar cell module M in the first embodiment, except for the points described later. Therefore, the anomaly detection system 1 of the solar cell module M according to the second embodiment can achieve the same effect as the anomaly detection system 1 of the solar cell module M in the first embodiment, except for the points described later.

[0056] As described above, in the anomaly determination system 1 of the solar cell module M in the first embodiment, the irradiation state control unit 1A, for example, makes the irradiation state of the solar cell cell C3 by placing a mask on a portion of the light-receiving surface of the solar cell cell (e.g., solar cell cell C3) whose parallel resistance component is to be determined (i.e., by applying a mask to block light) a first irradiation state. That is, in the anomaly determination system 1 of the solar cell module M in the first embodiment, the first irradiation state is a control state that reduces the incident light irradiating the solar cell cell C3 whose parallel resistance component is to be determined. Furthermore, in the anomaly determination system 1 of the solar cell module M according to the first embodiment, the illumination state control unit 1A changes the illumination state of the solar cell cell C3 to a second illumination state by irradiating the light-receiving surface of the solar cell cell C3 with light other than sunlight (e.g., the illumination light of an LED lamp) (i.e., by applying light enhancement). In other words, in the anomaly determination system 1 of the solar cell module M according to the first embodiment, the second illumination state is a state in which the incident light irradiating the solar cell cell C3, whose parallel resistance component is to be determined to be abnormal, is increased.

[0057] On the other hand, in the anomaly determination system 1 of the solar cell module M according to the second embodiment, the first irradiation state reduces the incident light irradiating the solar cell unit (e.g., solar cell unit C3) to which the abnormality of the parallel resistance component is to be determined. In this state, no control is performed, nor is control performed to increase the incident light irradiating the solar cell unit C3 used to determine whether the parallel resistance component is abnormal. Furthermore, in the anomaly determination system 1 of the solar cell module M in the second embodiment, the second irradiation state is the same as that of the anomaly determination system 1 of the solar cell module M in the first embodiment. The second irradiation state is a control state that increases the incident light irradiating the solar cell unit C3, which is to be determined whether there is an anomaly in the parallel resistance component.

[0058] [Third Embodiment] The following describes a third embodiment of the anomaly determination system and anomaly determination method for a solar cell module according to the present invention. The anomaly detection system 1 of the solar cell module M in the third embodiment is configured in the same way as the anomaly detection system 1 of the solar cell module M in the first embodiment, except for the points described later. Therefore, the anomaly detection system 1 of the solar cell module M according to the third embodiment can achieve the same effect as the anomaly detection system 1 of the solar cell module M in the first embodiment, except for the points described later.

[0059] In the anomaly determination system 1 of the solar cell module M according to the third embodiment, similar to the anomaly determination system 1 of the solar cell module M according to the first embodiment, the first irradiation state is a control state that reduces the incident light irradiating the solar cell unit (e.g., solar cell unit C3) whose parallel resistance component is to be determined to be abnormal. For example, the irradiation state control unit 1A sets the irradiation state of the solar cell unit C3 to the first irradiation state by configuring a mask on a portion of the light-receiving surface of the solar cell unit C3 whose parallel resistance component is to be determined to be abnormal (i.e., by applying a mask to block light). As described above, in the anomaly determination system 1 of the solar cell module M in the first embodiment, the illumination state control unit 1A illuminates the solar cell cell C3 with light other than sunlight (e.g., the illumination light of an LED lamp) (i.e., by applying light enhancement) to change the illumination state of the solar cell cell C3 to a second illumination state. That is, in the anomaly determination system 1 of the solar cell module M in the first embodiment, the second illumination state is a control state that increases the incident light illuminating the solar cell cell C3, whose parallel resistance component needs to be determined to be abnormal. On the other hand, in the anomaly detection system 1 of the solar cell module M according to the third embodiment, the second irradiation state is controlled to reduce the incident light irradiating the solar cell unit (e.g., solar cell unit C3) to which the parallel resistance component is to be determined to be abnormal. That is, neither of the states that increases the incident light irradiating the solar cell unit C3 to which the parallel resistance component is determined to be abnormal is performed. Example

[0060] Although the invention will be described in more detail by way of the following embodiments, the invention is not limited thereto and may be implemented with appropriate modifications without departing from the spirit of the invention.

[0061] Figure 9 This is a diagram showing the structure of the experimental apparatus in the embodiment. Experimental use in the examples Figure 9 The experimental setup shown is used. Details are as follows.

[0062] • Solar simulator: LED lights driven by 50Hz AC power (Sunway manufactures SW-GL100ED56W×2, SW-GL050ED48W×2, SW-GL030ED35W×4) • Solar cell module: Five equivalent polycrystalline silicon units (made in China, module size 16mm×63mm, short-circuit current 250mA under standard conditions, open voltage 0.6V, FF approximately 0.65) are connected in series. • The load resistance R of the solar cell module is ≒0Ω • When cell 2 or 3 in the solar cell module is simulated as a defective cell, a parallel connection resistor R is used. sh ≥40Ω. Prior experiments confirmed that the resistance R... sh The connection can simulate the defective units caused by moderate PID phenomenon. The solar cell module and the load resistor R are connected in series with a 32-turn coil. • Current clamp sensor: Manufactured by HIOKI Electric, model 9675, output voltage 0.1V / A • 2. Lock-in amplifier: NF circuit design block LI-575. Sensitivity is 1mV, time constant τ = 1.25s. • Light source for modulation: He-Ne laser (NOVETTE manufactured by JDSU, oscillation wavelength 633nm, random polarization 0.5mW). Modulation was performed using a 330Hz optical chopper (NF circuit design block, model 5584a) with a 50% duty cycle, and the intensity of the modulated light was adjusted using an absorption-type ND filter (optical density 1.0). • To simultaneously record the lock-in amplifier output and the actual unit voltage, a data logger (the same analog measurement unit NR-HA08 as the Keen NR-600) was used. Experimental results were analyzed by averaging the time values ​​recorded over a 5s measurement period within a 0.1ms sampling period.

[0063] [Example 1] For cell 2, which has a low voltage (-0.596V) in a normal cell without parallel resistors within a module without mask subtraction and optical enhancement, the actual cell voltage and lock-in amplifier output when mask subtraction and optical enhancement are implemented are shown in Table 1. Table 1 shows the effect of mask subtraction and optical enhancement on the low-voltage normal cell within the module. The voltage of normal cell 2 without parallel resistors decreases to -1.863V due to mask subtraction and increases to 0.373V due to optical enhancement. This is equivalent to... Figure 5 The content described in the text. For the lock-in amplifier output of normal unit 2 without parallel resistors, the ratio of mask subtraction to optical enhancement output values ​​is as high as 4.44.

[0064] [Table 1]

[0065] Next, for the normal unit 2 in Table 1, a parallel resistor of 40Ω was added as a defective simulation unit. The actual unit voltage and lock-in amplifier output when mask subtraction and optical enhancement were applied to the defective simulation unit 2 are shown in Table 2. Table 2 shows the effect of mask subtraction and optical enhancement on the low-voltage defective simulation units within the module. The voltage of the defective simulation unit 2 with the 40Ω parallel resistor decreased to -0.938V due to mask subtraction and increased to 0.116V due to optical enhancement, but the change was small compared to Table 1. This is equivalent to... Figure 6 The content described in the document states that for the locked amplifier output of a faulty analog unit 2 with a parallel resistor of 40Ω, the ratio of mask attenuation to optical enhancement output values ​​is as low as 1.73.

[0066] [Table 2]

[0067] Therefore, regarding the ratio of the modulated light to the lock-in amplifier output value under mask subtraction and light enhancement of the irradiated object unit, if the parallel resistance component of the irradiated object unit is high, the ratio is high. Conversely, if the parallel resistance component is low, it means that the quality of the parallel resistance component of the irradiated object unit can be estimated by using a ratio value close to 1.

[0068] [Example 2] Additionally, a 40Ω parallel resistor was added to unit 3 adjacent to unit 2, treating unit 3 as a faulty simulation unit. Unit 2, without the parallel resistor, remained normal. However, even with the adjacent unit 3 being faulty, the quality of the parallel resistance component of the normal unit 2 was investigated and summarized in Table 3. Table 3 shows the effects of mask reduction and light enhancement on the low-voltage normal unit when the adjacent unit is faulty. The voltage of the normal unit 2 decreased to -1.802V due to mask reduction and increased to 0.369V due to light enhancement. For the lock-in amplifier output of the normal unit 2, the ratio of the output value of mask reduction to light enhancement was as high as 6.18. That is, it means that even with the adjacent unit being faulty, the quality of the parallel resistance component of the target unit illuminated by the modulated light can be inferred.

[0069] [Table 3]

[0070] [Example 3] For cell 3, which has a high voltage (0.349V) in a normal cell without parallel resistors in a module without mask subtraction and optical enhancement, the actual cell voltage and lock-in amplifier output when mask subtraction and optical enhancement are implemented are shown in Table 4. Table 4 shows the effect of mask subtraction and optical enhancement on the high-voltage normal cell in the module. The voltage of normal cell 3 without parallel resistors decreases to -1.864V due to mask subtraction and increases to 0.390V due to optical enhancement. This is equivalent to... Figure 5 The content described in the text. For a normal 3-unit lock-in amplifier output without parallel resistors, the ratio of output values ​​under mask downlighting and optical uplighting is as high as 7.93.

[0071] [Table 4]

[0072] Next, for the normal unit 3 in Table 4, a parallel resistor of 40Ω was added as a faulty simulation unit. The actual unit voltage and lock-in amplifier output when mask subtraction and optical enhancement were applied to the faulty simulation unit 3 are shown in Table 5. Table 5 shows the effect of mask subtraction and optical enhancement on the high-voltage faulty simulation unit within the module. The voltage of the faulty simulation unit 3 with the 40Ω parallel resistor decreased to -0.884V due to mask subtraction and increased to 0.231V due to optical enhancement, but the change was small compared to Table 4. This is equivalent to... Figure 6 The content described in the document states that for the locked amplifier output of a faulty analog unit 3 with a parallel resistor of 40Ω, the ratio of mask attenuation to optical enhancement output values ​​is as low as 1.47.

[0073] [Table 5]

[0074] If this result is combined with Example 1, then regardless of the normal unit voltage, the ratio of the modulated light to the lock-in amplifier output value under mask subtraction and light enhancement relative to the irradiated target unit is high as long as the parallel resistance component of the irradiated target unit is high. Conversely, if the parallel resistance component is low, it means that the quality of the parallel resistance component of the irradiated target unit can be estimated by using a ratio value close to 1.

[0075] [Example 4] Additionally, a 40Ω parallel resistor was added to unit 2 adjacent to unit 3, treating unit 2 as a faulty analog unit. Unit 3, without the parallel resistor, remained normal. However, even with the adjacent unit 2 being faulty, the study investigated whether the quality of the parallel resistor component of the normal unit 3 could be inferred, and the results are summarized in Table 6. Table 6 shows the effects of mask subtraction and optical enhancement on the high-voltage normal unit when the adjacent unit is faulty. The voltage of the normal unit 2 decreased to -1.799V due to mask subtraction and increased to 0.380V due to optical enhancement. For the lock-in amplifier output of the normal unit 3, the ratio of the output value of mask subtraction to optical enhancement was as high as 5.70.

[0076] [Table 6]

[0077] Combining this result with Example 2 means that regardless of the normal cell voltage, even if adjacent cells are faulty, the quality of the parallel resistance component of the cell irradiated by the modulated light can be inferred.

[0078] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the specific structure is not limited to this embodiment, and appropriate changes can be made without departing from the spirit of the present invention. The structures described in the above embodiments and examples can also be combined.

[0079] In addition, all or part of the anomaly detection system 1 of the solar cell module M in the above embodiments can be implemented by dedicated hardware, or by memory and microprocessor. In addition, the anomaly detection system 1 of the solar cell module M consists entirely or partially of a memory and a CPU (central processing unit), and its functions can also be implemented by loading the program for implementing the functions of each part of the system into the memory and executing it. Alternatively, the program used to implement all or part of the functions of the anomaly detection system 1 for the solar cell module M can be recorded in a computer-readable storage medium, allowing the computer system to read and execute the program recorded in the storage medium, thereby processing each unit. The "computer system" referred to here includes hardware such as the operating system and peripheral devices. Furthermore, assuming the "computer system" utilizes a WWW system, it also includes a homepage providing environment (or display environment). Furthermore, "computer-readable storage medium" refers to removable media such as floppy disks, magneto-optical disks, ROMs, and CD-ROMs, as well as storage devices such as hard disks built into computer systems. In addition, "computer-readable storage medium" refers to a medium that dynamically maintains a program for a short period of time, similar to a communication line used to transmit a program via a network such as the Internet or a communication line such as a telephone line. It also includes memory that maintains a program for a certain period of time, such as volatile memory inside a computer system acting as a server or client. Furthermore, the aforementioned program can be a program used to implement the above functions, or it can achieve the above functions through combination with programs already recorded in the computer system. Explanation of symbols

[0080] 1: Anomaly detection system; 11: Modulated light irradiation unit; 111: Laser irradiation unit; 112: Optical chopper; 113: Ultrasonic control unit; 114: Reflector; 115: Filter; 12: Phase detection unit; 12a: Lock-in amplifier; 13: AC clamp sensor; 1A: Irradiation state control unit; 1B: Detection unit; 1B1: Phase detection output acquisition unit; 1B2: Ratio calculation unit; 1B3: Comparison unit; M: Solar cell module; C1, C2, C3, C4, C5: Solar cell units; RL: Load resistor.

Claims

1. An anomaly determination system for a solar cell module, used to determine whether each of a plurality of solar cell units constituting a solar cell module and connected in series is abnormal, the anomaly determination system for the solar cell module comprising; The irradiation state control unit controls the irradiation state of the solar cell cell to be determined to be at least a first irradiation state and a second irradiation state, wherein the second irradiation state is a state in which the short-circuit current of the solar cell cell to be determined is greater than that of the first irradiation state. A modulated light irradiation unit irradiates the solar cell unit to be determined with modulated light that is different from the incident light; The phase detection unit detects minute changes in the output current of the solar cell module caused by the modulation light irradiating the solar cell unit to be determined, and outputs the detection result as the phase detection unit output. The ratio calculation unit calculates the ratio between the output of the phase detection unit in the first irradiation state and the output of the phase detection unit in the second irradiation state. The comparison unit compares the ratio calculated by the ratio calculation unit with a preset threshold.

2. The anomaly detection system for a solar cell module according to claim 1, The first irradiation state is a state in which the incident light irradiating the solar cell unit to be determined is controlled to reduce the amount of incident light irradiating the solar cell unit to be determined. The second irradiation state is a state in which the incident light irradiating the solar cell unit to be determined is controlled to increase.

3. The anomaly detection system for a solar cell module according to claim 1, The first irradiation state is either a state in which neither control is performed to reduce the incident light irradiating the solar cell unit to be determined, nor control is performed to increase the incident light irradiating the solar cell unit to be determined. The second irradiation state is a state in which the incident light irradiating the solar cell unit to be determined is controlled to increase.

4. The anomaly detection system for a solar cell module according to claim 1, The first irradiation state is a state in which the incident light irradiating the solar cell unit to be determined is controlled to reduce the amount of incident light irradiating the solar cell unit to be determined. The second irradiation state is either a state in which neither control is performed to reduce the incident light irradiating the solar cell cell to be determined, nor control is performed to increase the incident light irradiating the solar cell cell to be determined.

5. A method for determining anomalies in a solar cell module, used to determine whether each of a plurality of solar cell units constituting a solar cell module and connected in series is abnormal, including: The irradiation state control step controls the irradiation state of the incident light to be determined solar cell unit to be at least a first irradiation state and a second irradiation state, wherein the second irradiation state is a state in which the short-circuit current of the solar cell unit to be determined is greater than that of the first irradiation state. The modulated light irradiation step involves irradiating the solar cell unit to be determined with modulated light that is different from the incident light. The phase detection step detects minute changes in the output current of the solar cell module caused by the modulation light illuminating the solar cell unit to be determined, and outputs the detection result as the phase detection unit output. The ratio calculation step calculates the ratio between the output of the phase detection unit in the first irradiation state and the output of the phase detection unit in the second irradiation state. The comparison step compares the ratio calculated by the ratio calculation unit with a preset threshold.

6. The anomaly determination method for a solar cell module according to claim 5, The modulated light irradiation step includes: In the first illumination state modulation light illumination step, when controlled to be in the first illumination state, the modulation light is irradiated onto the solar cell unit to be determined. The second irradiation state modulated light irradiation step involves irradiating the solar cell unit to be determined with the modulated light when it is controlled to be in the second irradiation state. The phase detection step includes: In the first irradiation state phase detection step, when controlled to the first irradiation state, the detection result of the minute change in the output current of the solar cell module caused by the modulation light irradiating the solar cell unit to be determined is used as the output of the phase detection unit of the first irradiation state. In the second irradiation state phase detection step, when controlled to the second irradiation state, the detection result of the minute change in the output current of the solar cell module caused by the modulation light irradiating the solar cell unit to be determined is output as the phase detection unit of the second irradiation state.

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