Electronic apparatus, control method of electronic apparatus, and program

Abstract

To provide an electronic apparatus which contributes to evaluation of a solar cell module, a control device of the electronic apparatus, and a program.SOLUTION: An electronic apparatus generates fourth information regarding the remaining period supposed that a solar cell moule can output predetermined power in its use environment on the basis of first information representing acetic acid concentration at a predetermined point of time in an encapsulant of the solar cell mole, second information representing the acetic acid concentration in the encapsulant at an expiration point of time of a period in which the solar cell moule can output predetermined power, and third information related to calculation of time variation of the acetic acid concentration in the encapsulant in the use environment of the solar cell module.SELECTED DRAWING: Figure 4

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to Japanese Patent Application No. 2023-124710, filed on July 31, 2023, the entire disclosure of which is incorporated herein by reference. [Technical field]

[0002] The present disclosure relates to an electronic device, a control method for an electronic device, and a program. [Background technology]

[0003] In recent years, research into the deterioration of solar cell modules (hereinafter sometimes referred to as "PV modules" or simply "modules"; also sometimes generally referred to as "solar cell panels" or "PV panels") has been progressing. For example, Non-Patent Document 1 discloses the deterioration of polymer materials in PV modules that operate in high temperature environments. Furthermore, for example, Patent Document 1 discloses an evaluation method for PV modules that measures water infiltration at a stage before deterioration of the PV module occurs. Furthermore, for example, Patent Document 2 discloses a management device that predicts a decrease in output of a PV module.

[0004] Furthermore, Non-Patent Documents 2 and 3 teach that acetic acid in the sealing material of a PV module causes corrosion degradation of electrodes, and that this acetic acid is ultimately involved in the degradation of the PV module. Patent Document 3 proposes a method for evaluating the lifespan of a PV module by detecting the degree of degradation of the sealing material of the PV module through glass. Patent Document 4 proposes a method for predicting the lifespan of a PV module based on the degree of degradation of the sealing material of the PV module and the degree of occurrence of the PID phenomenon (potential induced degradation) of the PV cell. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] Sarah Kurtz, et al., “Evaluation of High-Temperature Exposure of Rack-Mounted Photovoltaic Modules”, Conference Paper NREL / CP-520-45986, June2009 [Non-Patent Document 2] Jiang Zhu, et al., “Changes of solar cell parameters during damp-heat exposure”, Prog. Photovolt: Res. Appl. 2016, 24,1346-1358 [Non-Patent Document 3] Atsushi Masuda, et al., “Degradation by acetic acid for crystalline Si photovoltaic modules”, Jpn. J. Appl. Phys. 54, 04DR04, 2015 [Patent documents]

[0006] [Patent Document 1] JP 2007-165438 A [Patent Document 2] JP 2014-82309 A [Patent Document 3] JP 2017-55657 A [Patent Document 4] JP 2019-146338 A Summary of the Invention

[0007] The electronic device according to an embodiment includes: First information representing an acetic acid concentration in an encapsulant of the solar cell module at a predetermined time; Second information representing an acetic acid concentration in the sealing material at the end of a period during which the solar cell module can output a predetermined amount of power; and Based on third information related to calculation of a change over time in the concentration of acetic acid in the encapsulant in the usage environment of the solar cell module, Fourth information is generated that relates to a remaining period during which the solar cell module is expected to be able to output the specified power in the usage environment.

[0008] A method for controlling an electronic device according to an embodiment includes: Obtaining first information representing an acetic acid concentration at a predetermined time in an encapsulant of a solar cell module; acquiring second information representing an acetic acid concentration in the sealing material at the end of a period during which the solar cell module is capable of outputting a predetermined amount of power; acquiring third information related to calculation of a change over time in the concentration of acetic acid in the encapsulant in the usage environment of the solar cell module; generating fourth information regarding a remaining period during which the solar cell module is expected to be able to output the predetermined power in the usage environment based on the first information, the second information, and the third information; Includes.

[0009] A program according to an embodiment of the present invention includes: Obtaining first information representing an acetic acid concentration at a predetermined time in an encapsulant of a solar cell module; acquiring second information representing an acetic acid concentration in the sealing material at the end of a period during which the solar cell module is capable of outputting a predetermined amount of power; acquiring third information related to calculation of a change over time in the concentration of acetic acid in the encapsulant in the usage environment of the solar cell module; generating fourth information regarding a remaining period during which the solar cell module is expected to be able to output the predetermined power in the usage environment based on the first information, the second information, and the third information; Execute the command. [Brief description of the drawings]

[0010] [Figure 1]1 is a block diagram showing a schematic configuration example of an electronic device according to an embodiment; [Diagram 2] FIG. 1 is a diagram illustrating degradation of a PV module. [Diagram 3] FIG. 1 is a diagram illustrating the structure of a typical PV module. [Figure 4] FIG. 1 illustrates a logic flow for life expectancy prediction according to one embodiment. [Diagram 5] FIG. 13 is a diagram showing an example of the correspondence relationship between pH and acetic acid concentration in a sealing material of a PV module. [Figure 6] FIG. 13 is a diagram showing an example of the correspondence relationship between the Raman signal intensity ratio and the acetic acid concentration in the sealing material of a PV module. [Figure 7] 1 is a graph showing an example of Raman spectroscopy measurement performed by laser Raman analysis. [Figure 8] FIG. 13 is a graph showing the time course of acetic acid concentration in EVA when a PV module was subjected to a high temperature and high humidity test. [Figure 9] FIG. 1 is a diagram illustrating a hydrolysis reaction catalyzed by an acid. [Figure 10] FIG. 1 is a diagram showing an example of the time course of acetic acid concentration in a wet heat test at different temperatures. [Figure 11] FIG. 13 is a diagram showing the results of calculations performed by an electronic device according to an embodiment together with experimental results. [Figure 12] FIG. 13 is a diagram showing predicted values ​​of acetic acid concentration obtained by an electronic device according to an embodiment and measured values ​​of acetic acid concentration of a PV module installed in the field. [Figure 13] FIG. 13 is a diagram showing an example of the correlation between acetic acid concentration and FF characteristics. [Figure 14] FIG. 13 is a diagram showing the life span obtained by an electronic device according to an embodiment, together with the actual life span of a PV module installed in the field. [Figure 15] 1 is a graph showing an example of the correspondence relationship between the Raman signal intensity ratio and the acetic acid concentration when a UV test is performed. [Figure 16]1 is a graph showing an example of the waveform of a Raman spectrum when deterioration occurs due to UV light stress of an ultraviolet absorber UVA. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Predicting the lifespan of a PV module based on its degradation contributes to the evaluation of the PV module. The present disclosure relates to an electronic device, a control method for an electronic device, and a program that contribute to the evaluation of a PV module. According to one embodiment, it is possible to provide an electronic device, a control method for an electronic device, and a program that contribute to the evaluation of a PV module.

[0012] <Electronic equipment> Hereinafter, an electronic device according to an embodiment will be described with reference to the drawings.

[0013] In the present disclosure, an "electronic device" may be an electric device driven by electricity. In addition, in the present disclosure, a "user" may be a person (typically a human) who uses an electronic device according to an embodiment and / or a system including the electronic device. An assumed user of the electronic device according to an embodiment may be, for example, a person who wants to know the predicted lifespan of a PV module constituting a photovoltaic power generation system. A person who wants to know the predicted lifespan of a PV module may be, for example, a person who is considering introducing or selling a photovoltaic power generation system in a general household or a company. A person who wants to know the predicted lifespan of a PV module may be, for example, a person who inspects or evaluates a PV module in an inspection agency. A person who wants to know the predicted lifespan of a PV module may be, for example, a person who evaluates the asset value of a PV module in an insurance company or a financial institution. A person who wants to know the predicted lifespan of a PV module may be, for example, a person who inspects / replaces / takes safety measures / removes a PV module in a housing manufacturer or a housing owner. A assumed user of the electronic device according to an embodiment may be any person who wants to know the predicted lifespan of a PV module. Hereinafter, a person who operates an electronic device according to an embodiment (e.g., a consumer, a business, an engineer, or an inspection technician) will be simply referred to as a "user." If the lifespan of a PV module based on its degradation can be reasonably predicted, this will contribute to the evaluation of the PV module. The evaluation of a PV module here may refer to, for example, the evaluation of the remaining lifespan / remaining asset value of a (used) PV module.

[0014] The electronic device according to an embodiment typically outputs information about the life of the PV module in response to an input by a user's operation. For example, the user can input various information about the PV module whose life is to be measured to the electronic device according to an embodiment. The electronic device according to an embodiment outputs information about the prediction of the life of the PV module in response to various information about the PV module input by the user. The information about the prediction of the life of the PV module output by the electronic device according to an embodiment may be, for example, information about a period, such as the number of years until the life of the PV module. The information about the period until the life of the PV module may be, for example, a period during which the characteristics of the PV module (Pm characteristics or FF characteristics described later) can generate electricity without significantly decreasing, that is, a period during which the characteristics of the PV module decrease to a predetermined rate based on an initial value. The information about the prediction of the life of the PV module output in this manner can typically be displayed on a display device or the like. Thus, the user can know the predicted life of the PV module.

[0015] Furthermore, the electronic device according to an embodiment may generate information related to the lifetime of the PV module based on predetermined information. Here, the predetermined information may be information acquired by the electronic device according to an embodiment, or information provided to the electronic device according to an embodiment from another electronic device. For example, the electronic device according to an embodiment may acquire various information related to the PV module whose lifetime is to be measured. In this case, the electronic device according to an embodiment generates information related to prediction of the lifetime of the PV module based on the acquired various information.

[0016] FIG. 1 is a functional block diagram illustrating a schematic configuration of an electronic device according to an embodiment.

[0017] The electronic device according to an embodiment can be configured as, for example, a dedicated terminal. Meanwhile, the electronic device according to an embodiment may be configured as various devices such as, for example, a notebook PC (Personal Computer), a desktop PC, a tablet terminal, a smartphone, or a mobile phone. Furthermore, the function of the electronic device according to an embodiment may be realized as a part of the function of another electronic device. The function of the electronic device according to an embodiment can also be realized by executing an application program that performs the processing of the electronic device according to an embodiment in an arbitrary electronic device equipped with a computer. Furthermore, the electronic device according to an embodiment may be an arbitrary information processing device, or may include an arbitrary information processing device. Furthermore, the electronic device according to an embodiment may constitute at least a part of an arbitrary information processing device.

[0018] 1, the electronic device 1 according to an embodiment includes a control unit 10, an input unit 20, an output unit 30, a communication unit 40, and a storage unit 50. The electronic device 1 according to an embodiment may not include some of the functional units shown in FIG. 1, or may include functional units other than the functional units shown in FIG.

[0019] The control unit 10 controls and manages the entire electronic device 1, including each functional unit constituting the electronic device 1. The control unit 10 can be configured to include, for example, a CPU (Central Processing Unit) or a DSP (Digital Signal Processor). In one embodiment, the control unit 10 may be configured, for example, as a CPU (hardware) and a program (software) executed by the CPU. The control unit 10 may include a storage unit (memory) necessary for the operation of the control unit 10 as appropriate. In the electronic device 1 according to one embodiment, the control unit 10 may calculate and / or process various information related to prediction of the lifespan of the PV module.

[0020] The electronic device 1 may include at least one processor as a controller 10 to provide control and processing power for performing various functions. According to various embodiments, the at least one processor may be implemented as a single integrated circuit (IC) or as multiple communicatively connected integrated circuits and / or discrete circuits. The at least one processor may be implemented according to various known techniques.

[0021] In one embodiment, a processor includes one or more circuits or units configured to perform one or more data computation procedures or processes. For example, a processor may include one or more processors, controllers, microprocessors, microcontrollers, application specific integrated circuits (ASICs), digital signal processors, programmable logic devices, field programmable gate arrays, or any combination of these devices or configurations, or other known devices or configurations, to perform the functions described below.

[0022] The input unit 20 may be any input device used by a user to perform operations, such as keys (physical keys) like a keyboard and / or a pointing device like a mouse or a trackball. In one embodiment, the input unit 20 may be any known input device, and therefore a detailed description will be omitted. In one embodiment, the electronic device 1 may obtain various information required for predicting the life of the PV module from the input unit 20.

[0023] The output unit 30 outputs the processing results of the electronic device 1, etc. In one embodiment, the output unit 30 displays, for example, information related to prediction of the life span of a PV module as, for example, a display. In one embodiment, the output unit 30 may display characters or symbols, various objects, and / or various images constituting a screen that prompts the user to input predetermined information in order to output, for example, the above-mentioned information. Data necessary for display on the output unit 30 is supplied from the control unit 10.

[0024] The output unit 30 may be any display device such as a liquid crystal display, an organic electro-luminescence panel, or an inorganic electro-luminescence panel. The output unit 30 may display various information such as characters, figures, symbols, or graphs. The output unit 30 may display various objects constituting GUIs such as a pointer and buttons, as well as icon images, in order to prompt a user who operates the electronic device 1 to perform an operation. The output unit 30 may also be configured to include a backlight, as appropriate.

[0025] Furthermore, the output unit 30 is not necessarily limited to a device that provides a visual effect to the user. The output unit 30 may adopt any configuration as long as it can convey information related to the prediction of the lifespan of the PV module to the user. For example, the output unit 30 may be replaced by a speaker that conveys the information related to the prediction of the lifespan of the PV module by voice or the like. Furthermore, such a speaker may be provided in addition to the output unit 30, such as a display.

[0026] In one embodiment, the output unit 30 may be configured as, for example, a touch screen display together with the input unit 20. In this case, the touch screen display may include, as the output unit 30, a display device such as a liquid crystal display or an organic EL display. In addition, in this case, the touch screen display may include, as the input unit 20, a touch sensor or a touch panel that detects the presence or absence of a touch by a user and the position of the touch. In such a configuration, for example, keys such as a numeric keypad or icons can be displayed as objects on the output unit 30, and the operation of the operator touching the object can be detected by the input unit 20. The input unit 20 can employ various types of touch panels such as a resistive film type, a capacitive type, or an optical type.

[0027] The communication unit 40 can realize various functions including wireless communication. The communication unit 40 may realize communication by various communication methods such as LTE (Long Term Evolution). The communication unit 40 may include a modem whose communication method is standardized by ITU-T (International Telecommunication Union Telecommunication Standardization Sector). The communication unit 40 may wirelessly communicate with an external device such as an external server or a cloud server via a network, for example, via an antenna. In one embodiment, the communication unit 40 may receive various information from an external database such as an external server or a cloud server. In addition, the various information received by the communication unit 40 in this manner may be stored in the storage unit 50. In one embodiment, the electronic device 1 may receive or acquire various information required for predicting the life of the PV module via the communication unit 40.

[0028] The communication unit 40 is not limited to a functional unit that performs wireless communication. For example, the communication unit 40 may be configured as an interface for connecting to an external device via a cable or the like.

[0029] The storage unit 50 stores information acquired from the control unit 10 and the communication unit 40. The storage unit 50 also stores programs executed by the control unit 10. In addition, the storage unit 50 also stores various data such as the results of calculations performed by the control unit 10. The storage unit 50 will be described below as including a work memory for the control unit 10. The storage unit 50 can be configured with, for example, a semiconductor memory or a magnetic disk, but is not limited to these and can be any storage device. For example, the storage unit 50 may be an optical storage device such as an optical disk, or a magneto-optical disk. For example, the storage unit 50 may be a storage medium such as a memory card inserted into the electronic device 1 according to this embodiment. The storage unit 50 may be an internal memory of the CPU used as the control unit 10. In one embodiment, the electronic device 1 may store various information required for predicting the life of the PV module in the storage unit 50.

[0030] In FIG. 1, an input unit 20, an output unit 30, a communication unit 40, and a storage unit 50 may each be built into the electronic device 1 or provided outside the electronic device 1.

[0031] In the following description, various calculations and / or processes performed by the electronic device 1 according to an embodiment may be performed by the control unit 10. In the electronic device 1 according to an embodiment, information required for the various calculations and / or processes performed by the control unit 10 may be stored in the storage unit 50, may be acquired from the input unit 20, or may be received from the communication unit 40. In addition, in the electronic device 1 according to an embodiment, the results of the various calculations and / or processes performed by the control unit 10 may be stored in the storage unit 50, may be output from the output unit 30, or may be transmitted to the outside from the communication unit 40.

[0032] For example, in the storage unit 50, the activation energy Ea of the acetic acid generation reaction and the coefficient B0 of the acetic acid generation reaction obtained by calculation may be stored in a database together with the manufacturer, model number, manufacturing date, and other information related to the PV module. Also, in the storage unit 50, the effective stress time Heff per day and the annual effective temperature Teff of the PV module for each installation form obtained by calculation may be stored in a database together with the region name. Here, the effective stress time Heff is the effective stress time per day that becomes a constant value throughout the year, as described later. Also, the annual effective temperature Teff is the temperature of the PV module that becomes a constant value throughout the year, as described later. The actual effective stress time per day varies from day to day. Also, the actual temperature of the PV module varies from day to day. However, by using Heff and / or Teff, the calculation of the annual change in acetic acid concentration described later can be facilitated at each stage.

[0033] Next, the operations and / or processes performed by the electronic device 1 according to an embodiment will be described.

[0034] <Deterioration and Lifetime of PV Module> The electronic device 1 according to an embodiment predicts the lifetime of the PV module based on predetermined information regarding the PV module. More specifically, the electronic device 1 according to an embodiment generates information indicating the predicted lifetime of the PV module based on predetermined information regarding the PV module. The lifetime of the PV module is caused by the deterioration of the PV module. Therefore, the deterioration of the PV module will be described below.

[0035] Deterioration of a PV module is assumed to occur from several perspectives. In addition, several factors are assumed to be involved in the deterioration from each perspective. In this disclosure, "deterioration of a PV module" refers to a phenomenon in which the output of power generated by photovoltaic power generation in a PV module gradually decreases over time and then suddenly decreases. The applicant has found that ultraviolet rays (hereinafter also referred to as "UV") and / or moist heat stress are involved as factors in such deterioration of a PV module. Therefore, an electronic device 1 according to an embodiment predicts the lifespan of a PV module based on deterioration caused by UV and / or moist heat.

[0036] FIG. 2 is a diagram for explaining the deterioration of a PV module. In FIG. 2, the horizontal axis indicates time [years], and the vertical axis indicates the output by photovoltaic power generation of the PV module. That is, FIG. 2 shows an example of how the output of a general PV module changes over time. FIG. 2 shows how the output of a general PV module gradually decreases over time, and then suddenly decreases. As shown in FIG. 2, in a general PV module, initial deterioration of Di% per year occurs for M years from the start of photovoltaic power generation. After that, as shown in FIG. 2, in a general PV module, gradual aging deterioration of Da% per year occurs. After that, as shown in FIG. 2, at a certain point (the point of reaching the end of life), the general PV module undergoes rapid deterioration as described above. The "sudden decrease" in the output (generated power) by photovoltaic power generation of the PV module as described above corresponds to the "sudden deterioration" shown in FIG. 2. It is known that this sudden deterioration occurs due to acid generated in the encapsulant of the PV module due to UV and / or moist heat stress.

[0037] In a PV module, the modes of degradation that gradually (slowly) deteriorate over time and the mode that deteriorates rapidly at a certain point are not necessarily the same mode of degradation. In the degradation due to acids generated by UV and damp heat stress dealt with here, there is hardly any degradation that becomes the main component of (slow) aging degradation. Therefore, (slow) aging degradation is assumed to be degradation that occurs mainly due to other degradation modes different from the degradation due to acids caused by UV and damp heat stress. The rapid degradation due to acids generated in the above-mentioned encapsulant is a degradation mode in which the output rapidly decreases at a certain point. This rapid degradation is a degradation that suddenly appears at a certain point, overtaking the (slow) aging degradation due to other degradation modes up to that point.

[0038] Hereinafter, in order to explain the factors of degradation of the PV module as described above, the structure and degradation sites of the PV module will be explained.

[0039] <Structure of PV Module> Figure 3 is a diagram for explaining the structure of a PV module. Figure 3 is a diagram showing a cross-section of the PV module. Figure 3 schematically shows a cross-section of a typical PV module as an example. The PV module shown in Figure 3 has a thickness in the direction of the Z-axis shown in Figure 3. In the PV module shown in Figure 3, the positive direction side of the Z-axis is also referred to as the "front side", and the negative direction side of the Z-axis is also referred to as the "back side". In Figure 3, the illustration of parts that are not related or weakly related to the degradation of the PV module as described above is appropriately omitted.

[0040] As shown in Figure 3, the PV module 100 includes a front glass 110, a backsheet 120, and a solar cell 130. The front glass 110 constitutes the incident surface of light such as sunlight. The front glass 110 also has the function of a surface protection material. The backsheet 120 has the function of a back protection material. The solar cell 130 is composed of a semiconductor such as silicon (Si). The solar cell 130 absorbs light energy and converts it into electricity.

[0041] The solar cell 130 is sealed between the front glass 110 and the back sheet 120 by a front sealant 140 and a back sealant 150. In many PV modules, the sealant 140 and the sealant 150 are made of a copolymer of ethylene-vinyl acetate (EVA). For the front glass 110, a material with high light transmittance, such as white plate glass, tempered glass, or heat reflective glass, having a thickness of about 2 mm to 5 mm, is used. For the back sheet 120, for example, one or more resins selected from polypropylene and polyolefin are used, and an aluminum (Al) sheet may be further provided between the resins. The back sheet 120 may also be made of glass.

[0042] As shown in FIG. 3, the solar cell 130 includes electrodes 170 on the front and back sides of a semiconductor substrate made of silicon or the like. The electrodes 170 are formed using a metal such as silver (Ag) or aluminum (Al). Any number of the electrodes 170 may be formed on at least one of the front and back sides of the semiconductor substrate. As shown in FIG. 3, the electrodes 170 are formed on the semiconductor substrate via contact parts 180. In many PV modules, the contact parts 180 are formed by a thin glass layer. The electrodes 170 and the contact parts 180 are generally formed by printing a conductive paste such as silver containing glass frit on the semiconductor substrate and firing it. The electrodes 170 and the contact parts 180 may be formed using a film formation technique such as sputtering or a plating method, and the contact parts 180 may be formed by the same material as the electrodes 170. When the contact parts 180 are formed by Al, the contact parts 180 are configured without including a glass layer. In this case, in the contact portion 180, instead of a glass layer, an Al-doped Si layer and an Al-Si alloy layer in which an Al phase and a Si phase are mixed are formed.

[0043] Examples of typical solar cells 130 include BSF (Back Surface Field) cells or PERC (Passivated Emitter and Rear Cell) cells. The BSF cell may be configured to include at least any one of, for example, a front Ag electrode, an AR film, an N-type diffusion layer, a P-type Si substrate, a P+-type BSF layer, a back Al electrode, and a back Ag electrode. The PERC cell may be configured to include at least any one of, for example, a front Ag electrode, an AR film, an N-type diffusion layer, a P-type Si substrate, a passivation film, a back Al electrode, and a back Ag electrode. Here, the passivation film may be an AlOx film or a film formed by laminating an AlOx film and a SiN film.

[0044] <Deterioration sites of PV module> As described above, UV and / or damp heat stress is involved in the deterioration of the PV module 100 shown in FIG. 3. The deterioration in the PV module 100 involving UV and / or damp heat stress is caused by the corrosion of the contact portion (glass layer) 180 formed between the electrode 170 and the semiconductor substrate by the acid generated in the EVA due to the UV and / or damp heat stress. A thin glass layer with a thickness of about 10 to 100 nm is formed in the contact portion 180 between the electrode 170 and the semiconductor substrate. This glass layer has both the functions of electrical and mechanical bonding between the Ag electrode 170 and the Si semiconductor substrate. Also, since the thickness of this glass layer is thin, the electrical connection between the electrode 170 and the semiconductor substrate is not inhibited. Corrosion by acid can occur in either the front or back electrode 170 of the solar cell 130. However, since almost no UV light enters the back side of the solar cell 130, mainly damp heat stress is involved in the back electrode 170 of the solar cell 130. Corrosion by acid as described above can occur in the contact portion 180. Also, such corrosion by acid may occur in the electrode 170.

[0045] The EVA constituting the sealing materials 140 and 150 generates acid (mainly acetic acid) under stress of UV and / or moist heat. If the glass layer constituting the contact portion 180 is corroded by this acid, the mechanical bonding function of the glass layer is lost. Even if a certain level of mechanical bonding function is maintained, the corrosion of the glass layer increases electrical resistance and deteriorates the electrical bonding function. When a certain amount of the mechanical and / or electrical bonding function of the contact portion 180 is lost, the photogenerated carriers generated in the Si corresponding to the certain amount cannot be extracted from the Ag electrode. In this way, the solar cell characteristics of the PV module 100 deteriorate. The above-mentioned corrosion of the glass layer may occur in the contact portion 180. The corrosion of the glass layer may occur in the contact portion 180 and / or the electrode 170.

[0046] Corrosion of the contact portion 180 can be directly confirmed, for example, by performing cross-sectional SEM observation or EPMA analysis of the contact portion 180. That is, corrosion of the contact portion 180 can be recognized by disappearance of the glass layer of the contact portion 180 (voids between Ag and Si) corresponding to the degree of corrosion and / or compositional alteration of the glass layer. More simply, the presence or absence and / or the degree of corrosion of the glass layer can be determined by observing an EL image of the PV module. That is, corrosion of the contact portion 180 can be recognized by the occurrence of characteristic EL dark areas corresponding to the degree of corrosion and / or the expansion of the dark areas.

[0047] The output characteristics of the power generated by the photovoltaic power generation of the PV module 100 rapidly decrease when the stress of UV and / or moist heat reaches a certain level. This is a phenomenon that occurs as a result of the contact portion 180 being rapidly corroded by the increase in the above-mentioned acid. The indicator for the occurrence of such a phenomenon is when the acetic acid concentration (concentration of acetic acid molecules) in the EVA reaches 10 19 pieces / cm 3It can be set as the time point before and after. Here, the concentration of acetic acid molecules means, for example, the number of acetic acid molecules in the unit volume of EVA at 25 °C (298.15 K) and 1 atmosphere. The state where the output characteristics of the power generated by the PV module 100 by solar power generation have rapidly decreased may be regarded as the state where the PV module 100 has already reached the end of its life.

[0048] <Prediction of the Life of the PV Module> Next, the principle of predicting the life based on the deterioration of the PV module due to UV and / or damp heat by the electronic device 1 according to an embodiment will be described. Hereinafter, the prediction of the life based on the deterioration of the PV module due to UV and / or damp heat performed by the electronic device 1 according to an embodiment is also simply referred to as "life prediction" or "life expectancy prediction".

[0049] First, a basic principle for predicting a lifespan will be described. The "lifespan" predicted by the electronic device 1 according to an embodiment may be, for example, the time (period) from when the PV module starts generating power until the UV and / or moist heat stress reaches a predetermined amount and the power output characteristics begin to decrease rapidly. The "lifespan" predicted by the electronic device 1 according to an embodiment may be, for example, the time (period) from when the PV module starts generating power until the UV and / or moist heat stress reaches a predetermined amount and the power output characteristics begin to decrease rapidly. The "lifespan" predicted by the electronic device 1 according to an embodiment may be, for example, the time (period) from when the PV module starts generating power until the power output characteristics begin to decrease rapidly as described above and the power output reaches a predetermined degradation rate from the initial value. In these cases, the installation location and / or installation mode of the PV module may not be changed and the power generation period may continue. The "lifespan" predicted by the electronic device 1 according to an embodiment may be, for example, the time (period) from when the installation location and / or installation mode of the PV module is changed until the UV and / or moist heat stress reaches a predetermined amount and the power output characteristics begin to decrease rapidly. The "lifespan" predicted by the electronic device 1 according to an embodiment may be, for example, the time (period) from when the installation location and / or installation mode of the PV module is changed until the UV and / or moist heat stress reaches a predetermined amount and the power output characteristics begin to decrease rapidly. Hereinafter, the "lifespan" predicted by the electronic device 1 according to an embodiment is approximately the time until the fill factor (hereinafter also referred to as "FF characteristics") or the generated power (hereinafter also referred to as "Pm characteristics") decreases by 10% compared to the initial value. Here, the initial value may refer to a value measured immediately after the PV module is completed, or a value of the nominal maximum output (rated output) described in a catalog or label. However, the principle of predicting the lifespan of the electronic device 1 according to the embodiment may be adopted even when no sudden decrease in the power output characteristics is confirmed at the time when the FF characteristics or Pm characteristics decrease by 10% compared to the initial value. In this case, the principle of predicting the lifespan of the electronic device 1 according to the embodiment still holds true even if the time when the FF characteristics or Pm characteristics decrease by 10%, 20%, or 30% compared to the initial value is used as the guideline for the lifespan.Here, the output characteristics of the PV module are measured in accordance with the IEC 60891 standard (or JIS C8914).

[0050] As described above, the "lifespan" predicted by the electronic device 1 according to an embodiment is not necessarily limited to the time (period) assumed when a new PV module generates power immediately after completion. For example, it is assumed that a PV module, such as a used PV module, has already generated power for a certain period of time in the field (market). In such a case, the "lifespan" predicted by the electronic device 1 according to an embodiment may be the time (period) from the point after the certain period of time as the origin (zero year) until the end of the lifespan by continuing power generation thereafter. The "lifespan" predicted by the electronic device 1 according to an embodiment may be the time (period) from the point of time when the acetic acid concentration of a certain PV module is evaluated until the power output characteristic is suddenly reduced. In addition, the "lifespan" predicted by the electronic device 1 according to an embodiment may be the time (period) from the point of time when the acetic acid concentration of a certain PV module is evaluated until the power output reaches a predetermined degradation rate from the initial value.

[0051] The applicant has found a method for predicting the lifespan of a PV module due to deterioration caused by moist heat with reasonable and good accuracy from information on the concentration of acetic acid in EVA, which is a sealing material for the PV module. Hereinafter, such a method will be described. According to an electronic device 1 according to an embodiment, the lifespan of a PV module due to deterioration caused by moist heat can be predicted with reasonable and good accuracy based on information on the concentration of acetic acid in EVA, which is a sealing material for the PV module.

[0052] The above-mentioned Patent Document 4 refers to a method of predicting the degradation of a PV module from measurement information obtained using a Raman spectrometer. According to this method, it is necessary to perform measurements using Raman spectroscopy before and after a predetermined time has passed, that is, at multiple different times (multiple times). Therefore, according to this method, it takes a considerable amount of time (for example, years) to obtain information that predicts the remaining life of a PV module. For this reason, such a method has an aspect that makes it difficult to say that it is highly practical.

[0053] Furthermore, even if the above-mentioned method is used to perform Raman spectroscopy measurements before and after a certain amount of time has passed, there may be cases where the installation location and / or installation manner of the PV module is changed thereafter. In such cases, the above-mentioned method requires Raman spectroscopy measurements before and after a certain amount of time has passed since the installation location and / or installation manner of the PV module was changed. For example, it is necessary to perform Raman spectroscopy measurements at the time when the installation location and / or installation manner of the PV module is changed and at a time when a certain amount of time (e.g., years) has passed since the time of such change (i.e., at multiple different time points). For this reason, such a method still has an aspect that makes it difficult to say that it is highly practical.

[0054] In contrast, the electronic device 1 according to an embodiment can predict the lifespan (for example, remaining lifespan years) of a PV module based on deterioration due to wet heat, for example, by performing a measurement using Raman spectroscopy at a single time.

[0055] <Lifespan prediction logic flow> Fig. 4 is a diagram showing a logic flow of life prediction according to an embodiment. Fig. 4 shows a schematic diagram of a logic flow when the electronic device 1 according to an embodiment performs a life prediction. As shown in Fig. 4, the electronic device 1 according to an embodiment may perform a life prediction based on the following logic flow.

[0056] As shown in step S1 of FIG. 4, the control unit 10 of the electronic device 1 acquires information A0 of the acetic acid concentration at a predetermined time point in the sealing material (EVA) of the PV module whose life is to be predicted. Here, the predetermined time point may be, for example, the current time point, or the time point at which the life of the PV module is to be predicted. Specifically, the predetermined time point may be a time point immediately after the PV module is manufactured, or a time point several years after the PV module is installed in the field. Thus, in one embodiment, the time point at which the acetic acid concentration information A0 is acquired may be set to time zero (i.e., A0 may be set to an initial value) regardless of whether the PV module is immediately after its manufacture or has been installed in the field for several years. In this case, the electronic device 1 according to one embodiment can predict the remaining time (period such as years) from the time point at which the acetic acid concentration is A0 until the end of the life of the PV module.

[0057] In step S1, three methods for acquiring information A0 on the acetic acid concentration in the sealing material (EVA) of the PV module are described as examples. The control unit 10 of the electronic device 1 according to an embodiment may execute at least one of the three methods (method A, method B, and method C) described below to acquire information A0 on the acetic acid concentration in the sealing material (EVA) of the PV module. Although three methods are described below as examples, the method is not limited to these three methods, and any method may be used as long as information on the acetic acid concentration can be acquired directly or indirectly.

[0058] (Method A: Analysis by ion chromatography) In the analysis by ion chromatography, information on the concentration of acetic acid in EVA can be obtained by analyzing EVA recovered from the PV module using a specified method and / or conditions. This method is a destructive analysis because it requires the recovery of EVA from the PV module.

[0059] In ion chromatography, the concentration of acetic acid (more precisely, acetate ion CH 3 COO -The concentration of acetic acid is given in μg / g. To convert the μg / g unit of acetic acid concentration to the unit of / cm3, the following formula (1) can be used. In the following formula (1), the molecular weight of acetic acid is 60 g / mol, and the Avogadro constant is 6.022 × 10 23 Let us assume that. [ / cm 3 ]=[μg / g]×10 -6 x6.022x10 23 ÷60 ≒ [μg / g] × 10 16 (1) In the above formula (1), if a more accurate value is required, acetate ion (CH 3 COO - Considering that the molecular weight of 59 g / mol, 60 in the above formula (1) may be replaced with 59.

[0060] Here, the acetate ion CH obtained by ion chromatography is 3 COO - The concentration is CH 3 Molecules that exist as COOH and those that ionize to CH 3 COO - When measuring by ion chromatography, the CH 3 COOH is completely ionized to CH 3 COO - In other words, acetate ion CH obtained by ion chromatography is 3 COO - The concentration can be considered to indicate the total acetic acid concentration present in the EVA (the concentration of acetic acid initially present and the concentration of acetic acid produced by hydrolysis).

[0061] Next, a specific example of the analysis by ion chromatography will be further described. The analysis by the above-mentioned ion chromatography can be carried out, for example, according to the following specific procedure. [A-1] Dismantle the PV module and extract the EVA (for example, the EVA is about 2.5 cm x 6 cm in size, and may be extracted between the tabs near the center of the cell). [A-2] Place the EVA sample in a PP (polypropylene) bag together with ultrapure water and boil (for example, boil at 90°C for 2 hours). [A-3] Quantitatively analyze the acetate ions in the boiled solution using an ion chromatograph.

[0062] In the above-mentioned step [A-1], the tab (also called an interconnector) is a connection member that connects adjacent cells in series. In a type of solar cell having electrodes on both sides, the tab connected to the electrode on the front side of the solar cell is connected to the electrode on the back side of the adjacent solar cell. Two to twelve tabs are connected to an electrode (bus bar electrode) on one side. The EVA may be collected near the center of the solar cell. However, the EVA on the front side may be collected between the adjacent tabs, not on the tab.

[0063] In the above-mentioned step [A-2], the PP bag is not particularly limited to PP. As an example, the sample may be placed in a predetermined container, for example, a polypropylene bag.

[0064] In the above-mentioned step [A-3], the ion chromatograph may be, for example, an ICS-2100 manufactured by DIONEX.

[0065] (Method B: pH analysis) In pH analysis, information on the acetic acid concentration can be obtained by analyzing the encapsulant recovered from the PV module using a specified method and / or conditions. As with ion chromatography analysis, this method is destructive analysis because it requires the recovery of EVA from the PV module.

[0066] The pH information can be converted into acetic acid concentration information, for example, as follows. That is, the pH of a plurality of sealing material samples having different acetic acid concentrations is measured in advance, and a correspondence (correlation) between the acetic acid concentration (by, for example, ion chromatography) and the pH is obtained. FIG. 5 is a graph showing an example of the correspondence between pH and acetic acid concentration. A plurality of sealing material samples having different acetic acid concentrations can be obtained, for example, by subjecting PV modules to a high-temperature, high-humidity test and preparing a plurality of PV modules having different test times.

[0067] Next, a specific example of the pH analysis will be further described. The above-mentioned pH analysis can be carried out, for example, according to the following specific procedure. [B-1] Dismantle the PV module and extract the EVA (for example, the EVA is about 2.5 cm x 2.5 cm in size and may be extracted between the tabs near the center of the cell). [B-2] Cut the EVA sample into 2 mm squares and weigh it in a vial. [B-3] Add about 10 times the weight of the EVA sample to the vial with pure water and store in a refrigerator (for example, for 4 days). [B-4] Measure the pH of the solution in the vial using a pH meter

[0068] In the above-mentioned step [B-1], the tabs are connection members that connect adjacent cells in series. In a type of solar cell having electrodes on both sides, the tabs connected to the electrodes on the front side of the solar cell are connected to the electrodes on the back side of the adjacent solar cell. Two to twelve tabs are connected to an electrode (bus bar electrode) on one side. The EVA may be collected near the center of the solar cell. However, the EVA on the front side may be collected between the adjacent tabs, not on the tabs.

[0069] In the above-mentioned step [B-4], the stored vial may be taken out of the refrigerator, and the pH measurement may be performed after the solution has reached room temperature. The pH measuring device may be, for example, LAQUA twin AS-pH-22 (manufactured by Horiba, Ltd.). In the above-mentioned step [B-4], the acetic acid concentration may be obtained from a graph showing the correlation between pH and acetic acid concentration, such as that shown in FIG. 5.

[0070] In the above-mentioned (Method A: analysis by ion chromatography) and (Method B: pH analysis), the following points should be noted. First, since the values ​​obtained by measurement differ between EVA samples at the cell edge and EVA samples at the center, it is desirable to collect EVA samples at the same position in order to make comparisons. In addition, once a PV module is disassembled, components escape from the disassembled parts in a relatively short time, so it is desirable not to reuse EVA samples. Furthermore, if there are cracks in the backsheet when a PV module installed in the field is retrieved, attention should be paid to the effect of component desorption.

[0071] (Method C: Measurement by Raman spectroscopy) In Raman spectroscopy (Raman measurement), the encapsulant of the PV module is irradiated with probe light in a specific manner and / or under specific conditions, and information on the concentration of acetic acid can be obtained from the information on the signal intensity of the generated fluorescence (Raman signal intensity). This method is a non-destructive analysis because it does not require the recovery of the encapsulant from the PV module.

[0072] The information on the Raman signal intensity can be converted into information on the acetic acid concentration, for example, as follows. That is, Raman measurements can be performed in advance on a plurality of encapsulant samples with different acetic acid concentrations to obtain a correspondence relationship between the acetic acid concentration (for example, by ion chromatography) and the Raman signal intensity. FIG. 6 is a graph showing an example of the correspondence relationship (correlation) between the Raman signal intensity ratio and the acetic acid concentration. A plurality of encapsulant samples with different acetic acid concentrations can be obtained, for example, by subjecting PV modules to a high-temperature, high-humidity test and preparing a plurality of PV modules with different test times.

[0073] For Raman measurements, a handheld (mobile) Raman measuring instrument that can be used outdoors can be used. By using such an instrument, it is not necessary to retrieve the PV modules from their installation site, and measurements can be performed at the site where the PV modules are installed. For this reason, Raman measurements can be said to be an extremely convenient and economical method.

[0074] In the Raman measurement, measurements may be obtained at multiple locations on the surface of the PV module. In this case, if there is no significant difference in the distribution of the Raman signal intensity values, the average value can be used. On the other hand, if there is a significant difference in the distribution of the Raman signal intensity, the value with the largest signal intensity can be used. In this case, the time (e.g., years) until the end of the PV module's life predicted by the method described below will be the smallest value. This is a desirable method when one wishes to predict the life of the PV module with emphasis on safety (when one wishes to avoid overestimating the life even if it is possible to predict the life short). In addition, the average value and distribution width (2σ or 3σ) can also be obtained from the distribution of the signal intensity. In this case, the predicted value of the time (e.g., years) until the end of the PV module's life predicted by the method described below can also be treated as information having a distribution. In other words, the predicted value of the PV module's life obtained by using [average value-distribution width] can be used as a guide for the lower limit of the life. In addition, the predicted value of the PV module's life obtained by using [average value] can be used as a guide for the average value of the life. In addition, the predicted value of the lifespan of a PV module obtained by using [average value + distribution width] can be used as a guideline for the upper limit of the lifespan.

[0075] Next, a specific example of Raman measurement will be further described by taking measurement by laser Raman analysis as an example. Figure 7 is a graph showing an example of measurement by Raman spectroscopy performed by laser Raman analysis. Figure 7 will be described in detail below.

[0076] In FIG. 7, the samples subjected to the laser Raman analysis were samples subjected to a moist heat test under conditions of 125°C and 95% humidity. FIG. 7 shows the Raman spectrum of samples prepared for different moist heat test times (amount of moist heat stress) and subjected to laser Raman analysis. The horizontal axis of the graph shown in FIG. 7 shows the Raman shift, and the vertical axis shows the Raman signal intensity. Here, nine samples were analyzed, and nine Raman spectra are shown. In the graph shown in FIG. 7, the moist heat test time corresponding to each Raman spectrum is shown. From FIG. 7, it can be seen that the Raman signal intensity increases with the increase in moist heat test time. The bonding state of the encapsulant at the molecular level changes due to moist heat stress. The change in the Raman spectrum (change in signal intensity) is thought to correspond to such a change in the bonding state. The reaction involved in the change in the molecular level bonding state of the encapsulant due to moist heat stress includes the hydrolysis reaction described later. When the encapsulant is EVA, acetic acid is generated by the hydrolysis reaction as described later. Due to this background, it is believed that a correlation such as that shown in FIG. 6 exists between the Raman signal intensity and the acetic acid concentration in the sealing material.

[0077] When the above-mentioned measurement by Raman spectroscopy is carried out by laser Raman analysis, it can be carried out, for example, according to the specific procedure shown below. [C-1] Laser light is transmitted through the glass surface of the PV module, and the Raman signal intensity of the EVA on the front side is measured (for example, the focus of the laser light may be the interface between the glass and the EVA). [C-2] Prepare a correlation graph of the signal intensity ratio (fluorescence intensity ratio) in Raman measurement and the acetic acid concentration by ion chromatography analysis in advance (here, the signal intensity ratio in Raman measurement is, for example, the Raman shift 1800 to 2500 cm -1 The Raman signal intensity excluding the peak in the range of Raman shift 2800 cm -1The Raman signal intensity ratio may be divided by the Raman signal intensity (maximum intensity) caused by nearby CH. In other words, the target Raman signal intensity may be normalized by the reference Raman signal intensity. Using the signal intensity ratio obtained in this way, a correlation graph between the Raman signal intensity ratio (fluorescence intensity ratio) and the acetic acid concentration can be prepared. [C-3] Estimating acetic acid concentration using correlation graph

[0078] In the above-mentioned step [C-1], the excitation laser may have a wavelength in the range of about 500 to 560 nm. Specifically, the wavelength of the excitation laser may be, for example, 532 nm or 515 nm. The laser Raman spectrometer may be, for example, HR-800 (manufactured by Horiba, Ltd.).

[0079] In the above-mentioned step [C-2], the correlation graph prepared in advance may be, for example, as shown in FIG. -1 The CH maximum intensity in the vicinity of 1800 to 2500 cm may be taken as the peak intensity of the methylene group. -1 The Raman signal intensity other than the peak may be selected at any Raman shift within this range (within this range, the signal intensity is approximately the same at any Raman shift). -1 In the range, the Raman signal intensity other than the peak may be the average value of the signal intensity excluding the peak signal intensity in this range. In this case, the Raman signal intensity ratio (fluorescence intensity ratio) is [1800 to 2500 cm -1 signal intensity] / [Raman shift 2800cm -1 The signal strength in the vicinity may be given as

[0080] The correlation graph used in the above-mentioned step [C-3] may be, for example, as shown in FIG. 6. The Raman signal intensity ratio increases as the acetic acid concentration increases. Also, the acetic acid concentration increases as the amount of moist heat stress increases. In FIG. 6, the longer the time of the high temperature and high humidity test, the higher the acetic acid concentration and the larger the Raman signal intensity ratio.

[0081] In the above-mentioned (Method C: Measurement by Raman spectroscopy), the following points should be noted. First, by fixing the laser focus at the same position (for example, the interface between the glass and EVA), stable measurement results can be obtained. For this reason, it is recommended to adjust the measurement conditions according to the thickness of the surface glass. Furthermore, the Raman signal intensity (fluorescence intensity) actually increases due to the influence of not only moist heat but also UV light (described later). Furthermore, the normalization method is not limited to the above-mentioned method as long as it can be correlated with the acetic acid concentration.

[0082] <Preparation for predicting time changes (time transitions) in acetic acid concentration> Next, as shown in steps S2 to S5 of FIG. 4, the control unit 10 of the electronic device 1 prepares various physical quantities (calculates various physical quantities) in order to predict the time change (time transition) of the acetic acid concentration in the sealing material in the usage environment of the PV module to be predicted for life. Specifically, in step S2, the control unit 10 may calculate the coefficient B0 of the acetic acid production reaction. Also, in step S3, the control unit 10 may calculate the activation energy Ea of the acetic acid production reaction. Also, in step S4, the control unit 10 may calculate the annual effective temperature Teff of the PV module. Also, in step S5, the control unit 10 may calculate the effective stress time Heff per day. Specifically, the activation energy Ea of the acetic acid production reaction and the coefficient B0 of the acetic acid production reaction can be calculated based on the result of the time transition of the acetic acid concentration by a wet heat test at different temperatures, for example. The annual effective temperature Teff and the effective stress time Heff of the PV module can be calculated based on the temperature of the PV module measured throughout the year in the usage environment.

[0083] Here, the method of the damp heat test can be exemplified as follows. That is, the PV module is exposed to a predetermined atmosphere by placing it in a constant temperature and humidity tester set to predetermined temperature and humidity conditions. The temperature condition is in the range of 80 to 135°C. The humidity condition is in the range of 85 to 95% relative humidity. In this manner, the temperature condition and humidity condition may be set appropriately. For example, the damp heat test may be performed under conditions of a temperature of 85°C and a humidity of 85%. When the acetic acid concentration is measured by (Method A: analysis by ion chromatography) and (Method B: pH analysis), multiple PV modules of the same specifications are prepared and the multiple PV modules are placed in a tester. Then, at least one PV module is taken out at different predetermined times, and the acetic acid concentration in the sealing material in the PV module is measured, thereby obtaining the time transition of the acetic acid concentration. When the acetic acid concentration is measured by (Method C: measurement by Raman spectroscopy), the PV module is taken out of the tester at predetermined times, and the acetic acid concentration of the PV module is measured. The PV module is then placed in the test chamber again and exposed to the specified atmosphere. By repeating this process, the time transition of the acetic acid concentration can be obtained.

[0084] When performing the operations of steps S2 to S5, the control unit 10 may acquire installation information of a PV module that is the subject of life prediction and that has been installed in the field or is scheduled to be installed in the field. Specifically, the control unit 10 may acquire information such as the installation area (installation location), installation form (installation mode), and installation years of the PV module that is the subject of life prediction. The control unit 10 may prompt the user to input the above information via the input unit 20, or may acquire the above information from outside via the communication unit 40.

[0085] In steps S2 to S5, the control unit 10 may prompt the user to input installation information of the PV module to be subjected to life prediction. The installation information of the PV module may be, for example, information on the installation area (location of the field where the PV module is installed), information on the installation form (how the PV module is installed in the field), and information on the installation period (how long the PV module has been installed in the field (e.g., number of years)).

[0086] The information on the installation area (location of the field where the PV module is installed) may be, for example, information on the address or location (latitude, longitude and / or place name) where the PV module is installed. The control unit 10 may obtain, based on the information on the installation area, temperature information published by the Japan Meteorological Agency or the like in the installation area or around the installation area via the communication unit 40.

[0087] Furthermore, the information on the installation form (how it is installed in the field) may be information such as whether the PV module to be the subject of life prediction is installed in the ground, on a folded-plate roof, or on a residential roof. The temperature of a PV module tends to increase in the following order: ground installation, installation on a folded-plate roof, and installation on a residential roof. This is because the ease of heat dissipation from the back side of the PV module differs depending on the installation form of the PV module. Since the back side of a ground-mounted PV module is an open space, wind can easily pass through and heat can be easily dissipated. For this reason, the temperature of a ground-mounted PV module is relatively low. For a PV module on a residential roof, the space on the back side of the module is relatively narrow, making it difficult to dissipate heat. For this reason, the temperature of a PV module on a residential roof is relatively high.

[0088] In addition, information on the installation period (the period during which the PV module was installed in the field (e.g., the number of years)) may be information on the period during which the PV module to be the subject of life prediction was installed in the field (e.g., the number of years (Y0 [years])).

[0089] In steps S2 to S5, the control unit 10 may obtain the installation information of the PV module from an external device via the communication unit 40 or the like, instead of prompting the user to input the installation information of the PV module.

[0090] The following describes a calculation formula for predicting the aging trend of acetic acid concentration in the encapsulant of a PV module. First, a prediction formula for the time trend of acetic acid concentration based on the hydrolysis reaction of the encapsulant (EVA) of the PV module catalyzed by an acid is derived, and then a method for dealing with the time trend of acetic acid concentration in the environment of a field where the temperature of the PV module fluctuates is described.

[0091] <Prediction formula for the time trend of acetic acid concentration based on the hydrolysis reaction of EVA catalyzed by an acid> Acetic acid is known to be produced by the hydrolysis reaction of EVA. Figure 8 is a graph showing the time trend of acetic acid concentration [ / cm 3 in EVA when the PV module is put into a high-temperature and high-humidity test. Here, the acetic acid concentration [ / cm 3 is based on the acetic acid concentration [μg / g] obtained by ion chromatography. As shown in Figure 8, the acetic acid concentration increases exponentially with the passage of time. This exponential increase suggests that the hydrolysis reaction is a hydrolysis reaction catalyzed by an acid. That is, the H + (H 3 O + ) released by the acetic acid itself generated by the reaction shown in Figure 9 acts as a catalyst, indicating that the hydrolysis reaction of EVA is accelerated.

[0092] Here, the hydrolysis reaction catalyzed by an acid is described by the reaction formula shown in the following formula (2). EV-A + H 2 O + n·H 3 O + → EV-OH + AH + n·H 3 O + (2)

[0093] In the above formula (2), A represents an acetic acid group, AH represents acetic acid, and EV-A represents EVA (Ethylene Vinyl Acetate). OH represents an OH group. EV-OH represents a state in which an OH group is bonded in place of the acetate group A in EVA-A. In this case, the differential equation describing the time transition of the acetic acid concentration [AH] can be expressed as the following formula (3) (hereinafter, the unit of concentration is [ / cm 3 ]). d[AH] / dt=C·[EV-A]·[H 2 O]·{1+α·[H 3 O + ] n} (3)

[0094] In this case, 1≪α·[H 3 O + ] n Therefore, it can be considered that the following equation (4) holds true. d[AH] / dt=C·[EV-A]·[H 2 O]·α·[H 3 O + ] n (4)

[0095] In the above formula (4), the coefficient C is a parameter related to the rate of hydrolysis reaction in the absence of acid catalysis. In addition, the coefficient α is a parameter that represents the degree of influence when acid catalysis is present. Both of these parameters may be values ​​determined by experiment. In other words, C·α, the product of coefficient C and coefficient α, is a parameter determined by experiment.

[0096] The ionization reaction of acetic acid (instantaneous equilibrium) is described by the following equation (5). AH + H 2 O ⇔ A - + H 3 O + (5)

[0097] Here, using the equilibrium constant Keq, the following equilibrium equation (6) holds: Keq = {[A - ]·[H3 O + ]} / {[AH]·[H 2 O]} (6)

[0098] Here, in the case where the presence of molecules that are acid or alkaline components other than acetic acid in the EVA system under consideration can be sufficiently ignored, [A - ]≒[H 3 O + Therefore, the following equation (7) holds: [H 3 O + ] 2 =Keq·[AH]·[H 2 O] (7)

[0099] From the above formula (4) and formula (7), the following formula (8) can be derived. d[AH] / dt=C·[EV-A]·[H 2 O]·α·{Keq·[AH]·[H 2 O]} (n / 2) (8)

[0100] Here, B is defined as follows: B=C·[EV-A]·[H 2 O]·α·{Keq·[H 2 O]} (n / 2) (9)

[0101] From the above formula (8) and formula (9), the following formula (10) can be derived. d[AH] / dt=B·[AH] (n / 2) (10)

[0102] The solutions to the above equation (10) are given by the following equations (11) and (12). When n=1: [AH]=(B / 2) 2 t 2 (11) When n = 2: [AH] = A0 exp(B t) (12)

[0103] Here, the experimental fact (exponential increase in acetic acid concentration) can be explained by the latter case of n = 2 (Equation (12)). Also, A0 is the acetic acid concentration at t = 0, i.e., the initial value. A0 can be obtained by analyzing the EVA of the PV module before it is put into the high temperature and high humidity test (for example, it can be analyzed by ion chromatography, etc.).

[0104] Hereinafter, equation (12) will be expressed as the following equation (13). A(t)=A0·exp(B·t) (13)

[0105] Here, equation (10) for n=2 is written as equation (14) below. d[AH] / dt=B·[AH] (14) In this case, B is expressed as the following equation (15). B=C·[EV-A]·[H 2 O] 2 ·α·Keq (15)

[0106] As can be seen from the above, B has the same water concentration in EVA [H 2 O] is included. In other words, it is thought that the acetic acid production reaction accelerates as the moisture concentration in EVA increases. This is related to the humidity correction in the remaining life prediction, which will be explained later. However, it should be noted that the absolute humidity of the air is not the only factor that determines the moisture concentration in EVA.

[0107] In other words, resin sealing materials have inherent moisture adsorption properties (they have the ability to retain moisture). Therefore, even if the absolute humidity in the air were to drop by half (drop rate = 50%), the drop in moisture concentration in the EVA would be significantly less than half (drop rate < 50%).

[0108] FIG. 10 is a graph showing an example of the time transition of acetic acid concentration in a moist heat test at different temperatures. In FIG. 10, the analytical values ​​of acetic acid concentration at each time are indicated by black circles (●) and white circles (◯). As shown in FIG. 10, it can be seen that the higher the temperature, the faster the rate of acetic acid production. This temperature dependency is thought to be described by the Arrhenius equation. In other words, it is thought that B in the above formula (15) can be rewritten as the following formula (16). B = B0 exp(-qEa / kT) (16)

[0109] In the above formula (16), q represents the elementary charge, k represents the Boltzmann constant, T represents the absolute temperature [K], B0 represents a coefficient, and Ea represents the activation energy of the reaction [eV]. Additionally, qEa means q×Ea, and kT means k×T. B0 and Ea are physical quantities determined by experiment. In addition, by comparing the above formula (16) with the above formula (15), it is possible to determine the moisture concentration in EVA [H 2 It can be seen that the information included is [O].

[0110] From the above equations (13) and (16), the following equation (17) can be obtained. A(t)=A0·exp(B0·exp(-qEa / kT)·t) (17)

[0111] Here, B0 and Ea can be uniquely determined so that formula (17) explains the experimental results (i.e., so that formula (17) fits the experimental results). The experimental results used may be information on the hygrothermal test product, including the temperature conditions and test results (acetic acid concentration and test time) of the hygrothermal test. The experimental results used may also be information on the field installation product, including the installation period, temperature (e.g., annual effective temperature), and acetic acid concentration of the PV module installed in the field. Furthermore, the experimental results used may be a combination of information on the hygrothermal test product and information on the field installation product. That is, the experimental results used may be information based on at least two levels of temperature conditions. For example, the two levels may be two levels for the experimental temperature, two levels for the annual effective temperature of the panel in the field (described later), or a combination of one level for the experimental temperature and one level for the field temperature. Specifically, B0 and Ea can obtain the following values. In this case, the unit of time t is [h]. B0 ≒ 1.6 × 10 7 Ea ≒ 0.72 eV The above may correspond to the processes performed in steps S2 and S3 shown in FIG.

[0112] In the damp heat test shown in Fig. 10, the PV module used as the test sample was one that had not yet been installed in the field after manufacture (immediately after manufacture). The acetic acid concentration (initial value A0) of this PV module, when the time when the damp heat test was started was set to zero, was A0 ≈ 2 × 10 17 [ / cm 3 The acetic acid concentration immediately after manufacture (initial value A0) may vary to some extent depending on the type and / or specifications of the PV module (differences in the specifications of the EVA used and / or process conditions for manufacturing the PV module). If a more accurate value is required for the acetic acid concentration immediately after manufacture (initial value A0), the value can be obtained by a method using the Raman measurement described above for the PV module before the moist heat test, depending on the type and / or specifications of the PV module. If the accurate initial value is unknown, the above-mentioned acetic acid concentration of 2 × 1017 [ / cm 3 ] Values ​​around this value can be used as a guideline for A0.

[0113] FIG. 11 is a graph showing the results of calculations performed according to equation (17) using the above values ​​of A0, B0, and Ea, together with the experimental results. In FIG. 11, the calculation results are shown by solid and dotted lines. As shown in FIG. 11, it can be confirmed that the above calculation results reproduce the experimental results with good accuracy. This indicates the validity of the values ​​of B0 and Ea obtained as described above. However, the above value of B0 (approximately 1.6×10 7 ) is a value obtained under high humidity conditions (relative humidity of about 85 to 95%). Under humidity conditions in an actual field environment (outdoor environment) (relative humidity ≦ about 85%), appropriate corrections may be made as described below.

[0114] The above-mentioned B0 and Ea can basically be regarded as values ​​specific to EVA. Therefore, if the PV module uses EVA as the encapsulant, the above-mentioned values ​​can be used as guide values ​​for B0 and Ea. However, these values ​​of B0 and Ea may vary slightly depending on the additive added to EVA and / or the heat treatment conditions of EVA (conditions in the lamination process and / or crosslinking process). Therefore, if it is desired to obtain B0 and Ea more accurately, the results of two levels of moist heat tests may be obtained for the temperature shown in FIG. 10 according to the type and / or specifications of the PV module (differences in the specifications of the EVA used and / or the process conditions for manufacturing the PV module). In this case, it is sufficient to obtain B0 and Ea that give the calculation formula (17) that can best reproduce the test results shown in FIG. 11. Here, the initial value A0 of the acetic acid concentration can be obtained by a method using the above-mentioned Raman measurement or the like for the PV module before the moist heat test.

[0115] For example, if the target PV module has already been installed in the field for a certain period of time, the above values ​​(B0 ≒ 1.6 × 10 7It is possible to use (Ea ≒ 0.72 eV). Further, when more accurate values of B0 and Ea are desired, the necessary number of PV modules installed in the field may be collected, and the results of a two-level damp heat test may be obtained for the temperatures as shown in Fig. 10. In this case, B0 and Ea may be determined that give the calculation formula (17) that best reproduces the test results as shown in Fig. 11. The acetic acid concentration at the time when the PV module has been installed in the field for a certain period (this is defined as the initial value A0) can be determined by a method using Raman measurement or the like described above for the PV module before the damp heat test is performed. In particular, when using a handy type (mobile type) Raman measurement device, the acetic acid concentration (initial value A0) of the PV module can be determined while it is installed in the field. The acetic acid concentration (initial value A0) of the PV module at the time when it has been installed in the field for a certain period generally increases in response to the environmental stress received in the field with respect to the acetic acid concentration at the time immediately after the PV module is manufactured. Also, the acetic acid concentration (initial value A0) of the PV module at the time when it has been installed in the field for a certain period may vary in the amount of increase with respect to the concentration at the time immediately after manufacture depending on the number of years of field installation and / or the installation form, etc.

[0116] <Method for Handling Temporal Change in Acetic Acid Concentration in Environment of Field Where Temperature of PV Module Fluctuates> Next, a method for predicting the temporal change in acetic acid concentration under the installation conditions of a field where the temperature of the PV module fluctuates will be described. This may be considered to correspond to the processes performed in steps S4 and S5 shown in Fig. 4. Here, a method using the concepts of the annual effective temperature of the PV module (hereinafter, also simply referred to as the "annual effective temperature") and the effective stress time per day (hereinafter, also simply referred to as the "effective stress time") will be described.

[0117] <When Temperature Information of PV Module is Available> First, the case where the temperature of the PV module is measured throughout the year and is known will be described. In this case, the following formula (18) is constructed. Σ{exp(-qEa / kT)·Δt}=exp(-qEa / kTeff)·365·Heff (18) Here, qEa means q×Ea, and kTeff means k×Teff.

[0118] The above equation (18) generally allows the time-integrated sum of reaction rates (left side) to be expressed using Teff and Heff (right side) in a reaction that proceeds at a rate proportional to exp(-qEa / kT). Here, exp(-qEa / kT) can also be interpreted as an index of the amount of heat stress per unit time for a reaction whose activation energy is Ea. The above equation (18) can also be interpreted as allowing the time-integrated sum of heat stress (left side) to be expressed using Teff and Heff (right side). By using Teff and Heff, it is much easier to calculate the annual change in acetic acid concentration, as described below.

[0119] In the above formula (18), Σ represents the cumulative sum (total) for each time Δt throughout the year, Δt represents the time of the cumulative step, Teff represents the effective annual temperature of the PV module, and Heff represents the effective stress time per day that can be used throughout the year. The units of T and Teff are absolute temperature [K]. exp(-qEa / kT) and exp(-qEa / kTeff) represent amounts proportional to the amount of thermal stress per unit time. Δt and Heff can be in the same time unit, for example, minutes [min] or hours [h]. In an example where the time unit is [h], Δt = 1 [h] and Heff = 4.0 [h] ± 0.4 [h] can be used.

[0120] By solving the above equation (18) for Teff, the following equation (19) can be obtained: This may be considered to correspond to the process performed in step S4 shown in FIG. Teff=(-qEa / k) / ln[Σ{exp(-qEa / kT)·Δt} / (Heff·365)] (19)

[0121] That is, when the PV module temperature T at each time interval Δt throughout the year is known, the annual effective temperature Teff can be calculated using the above formula (19). Then, by using the annual effective temperature Teff shown in the above formula (19), the annual change in the acetic acid concentration in the EVA of the PV module can be predicted as follows in formula (20). A(Y)=A0·exp(B0·exp(-qEa / kTeff)·Heff·365·Y) (20)

[0122] In the above formula (20), A0 represents the initial acetic acid concentration, Y represents the number of years (unit: [Y]), and A(Y) represents the acetic acid concentration Y years after the time point when the acetic acid concentration is A0 (zero-year time point).

[0123] <When there is no temperature information of the PV module> Next, the case where there is no measurement information on the temperature of the PV module will be described. When there is no measurement information on the temperature of the PV module, an estimated value of the temperature of the PV module is obtained using the air temperature information and the reference value ΔT information for each installation form of the PV module. Here, the reference value ΔT is the temperature difference between the temperature of the PV module during power generation and the air temperature, and is given as follows for each installation form of the PV module. Stand-alone installation: ΔT = 25°C ± 5°C Installation on a corrugated roof: ΔT = 30°C ± 5°C Installation on a residential roof: ΔT = 35°C ± 5°C

[0124] The applicant has confirmed from previous research that the relational expression of the following formula (21) can be constructed. Σ{exp(-qEa / kTmp)·Heff}=exp(-qEa / kTeff)·365·Heff (21)

[0125] In the above formula (21), Σ is the integrated sum (total sum) for 365 days per day throughout the year. Also, Tmp represents the maximum temperature of the PV module per day throughout the year in units of [K], and can be obtained from the following formula (22). Tmp=Tmax+ΔT (22)

[0126] In the above formula (22), Tmax is the maximum temperature for each day throughout the year expressed in [K]. If there is temperature information about the location where the PV module is installed among the temperature information published by the Japan Meteorological Agency or other organizations, this information can be used for Tmax. Also, if there is no temperature information about the location where the PV module is installed, the temperature information of a location close to the location where the PV module is installed can be used.

[0127] By solving the above equation (21) for Teff, the following equation (23) can be obtained. Teff=(-qEa / k) / ln[Σ{exp(-qEa / kTmp)·Heff} / (Heff·365)] =(-qEa / k) / ln[Σ{exp(-qEa / kTmp)} / 365] (23)

[0128] Using the annual effective temperature Teff shown in the above equation (23), the annual change in the acetic acid concentration in the EVA of the PV module can be predicted as shown in the following equation (24). A(Y)=A0·exp(B0·exp(-qEa / kTeff)·Heff·365·Y) (24)

[0129] <When using the monthly average maximum temperature instead of the daily maximum temperature> In the above formula (22), a similar prediction formula can be obtained by using the monthly average maximum temperature Tmax' instead of the daily maximum temperature Tmax. According to this method, prediction processing can be performed more easily without significantly decreasing prediction accuracy compared to the case where the daily maximum temperature Tmax is used. In this case, a relational formula such as the following formula (25) can be first constructed. Σ{exp(-qEa / kTmp')·Heff·Day}=exp(-qEa / kTeff)·365·Heff (25)

[0130] In the above formula (25), Σ represents the cumulative sum (total) of each of the 12 months throughout the year. Also, Day is set to 31 days for January, March, May, July, August, October, and December, 30 days for April, June, September, and November, and 28 days for February.

[0131] Furthermore, in the above equation (25), Tmp' is the average maximum temperature of the PV module for each month throughout the year expressed in units of [K], and is obtained from the following equation (26). Tmp' = Tmax' + ΔT (26)

[0132] In the above formula (26), Tmax' is the average maximum temperature for each month throughout the year expressed in [K]. If there is temperature information about the location where the PV module is installed among the temperature information published by the Japan Meteorological Agency or other organizations, this information can be used for Tmax'. Also, if there is no temperature information about the location where the PV module is installed, the temperature information of a location close to the location where the PV module is installed can be used.

[0133] By solving the above equation (25) for Teff, the following equation (27) can be obtained. Teff=(-qEa / k) / ln[Σ{exp(-qEa / kTmp')·Heff·Day} / (Heff·365)] =(-qEa / k) / ln[Σ{exp(-qEa / kTmp')·Day} / 365] (27)

[0134] Using the annual effective temperature Teff shown in the above equation (27), the annual change in the acetic acid concentration in the EVA of the PV module can be predicted as shown in the following equation (28). A(Y)=A0·exp(B0·exp(-qEa / kTeff)·Heff·365·Y) (28)

[0135] <When using the annual average daily maximum temperature> Furthermore, the applicant has confirmed from previous research that the annual effective temperature Teff satisfies the relationship of the following equation (29). Teff≒Tmax annual average +ΔT (29)

[0136] In the above formula (29), the annual average Tmax is the annual average value of the maximum temperature Tmax for each day. The annual average value of Tmax may be the average value of the maximum temperature in the field on a daily basis for one year, or may be the average value of the monthly average of the maximum temperature in the field on a daily basis for one year. Using the annual effective temperature Teff shown in the above formula (29), the annual change in the acetic acid concentration in the EVA of the PV module can be predicted as shown in the following formula (30). A(Y)=A0·exp(B0·exp(-qEa / kTeff)·Heff·365·Y) (30)

[0137] <About effective stress time> Next, the calculation of the effective stress time Heff per day will be described. This may be considered to correspond to the process performed in step S5 shown in FIG. 4. Here, the effective stress time Heff per day indicates the effective stress time per day that is a constant value throughout the year. On the other hand, it is possible to consider an effective stress time per day that is different every day throughout the year, and this will be represented by heff. Below, an explanation of heff will be given first, followed by an explanation of Heff.

[0138] <About effective stress time per day heff> First, the effective stress time heff per day will be explained. The heat stress per day can be expressed as the following equation (31). Σexp(-qEa / kT)=exp(-qEa / kTmp)·heff (31) Here, qEa means q×Ea, and kTmp means k×Tmp.

[0139] In the above formula (31), the summation interval on the left side is 24 hours for every hour. In this way, the effective stress time heff per day may be the value obtained by dividing Σexp(-qEa / kT) by exp(-qEa / kTmp). Here, Σexp(-qEa / kT) is the summation in units of a given time of an amount proportional to the stress due to moist heat per day in the PV module installed in the field. Also, exp(-qEa / kTmp) is an amount proportional to the stress due to moist heat per unit time at the maximum temperature of the PV module installed in the field. Also, Tmp and heff are values ​​that may differ from day to day.

[0140] <About the effective stress time Heff per day, which is a constant value throughout the year> Next, we will explain a method of using the effective stress time Heff per day, which is a constant value (generalized value) per year, instead of the effective stress time Heff per day, which differs for each day in a year. Heff and Heff are related as shown in the following equation (32). Σ{exp(-qEa / kTmp)·heff}=exp(-qEa / kTeff)·Heff·365 (32) In the above formula (32), Σ is the cumulative sum (total) of each day for 365 days throughout the year.

[0141] From previous research, the applicant has confirmed that Heff = 4.0 [h] ± 0.4 [h] can be used as a guideline for the effective stress time Heff per day per year that can withstand general-purpose use. More preferably, when the annual average temperature of the maximum temperature Tmax in one day is written as "annual average Tmax", Heff [h] = 0.108 × annual average Tmax [℃] + 1.7. Even more preferably, Heff [h] = -0.00248 × (annual average Tmax [℃]) 2 +0.245×Tmax annual average [℃]. Also, when the module temperature in the field is available, the annual median of the effective stress time heff per day, which varies from day to day throughout the year, can be used as Heff.

[0142] FIG. 12 shows the predicted acetic acid concentration (indicated by the dashed line) obtained as described above and the measured acetic acid concentration of the PV module installed in the field (indicated by the black circles (●)). That is, FIG. 12 is a diagram showing the relationship between the number of years the PV module has been installed in the field and the acetic acid concentration in the encapsulant of the PV module. As shown in FIG. 12, it can be seen that the two show a relatively good degree of agreement.

[0143] <Acetic acid concentration at the time when the PV module reaches the end of its life> Next, as shown in step S6 of FIG. 4, the control unit 10 of the electronic device 1 obtains information A on the acetic acid concentration at the time when the PV module to be predicted for its life reaches the end of its life T (hereinafter also referred to as "acetic acid concentration A at the end of life" T " or "end-of-life acetic acid concentration A" T ").

[0144] When the corrosion of the electrode 170 and / or the contact portion 180 of the PV module due to acetic acid progresses, the electrical conductivity between the electrode and the semiconductor silicon deteriorates, and the contact resistance between the electrode and the semiconductor increases. When the contact resistance increases, the operation of extracting the carriers generated in the semiconductor silicon by the photovoltaic conversion effect to the electrode is inhibited, and the output of the PV module is reduced. It is known that the output of the PV module is determined by three pieces of information: the short-circuit current Isc, the open-circuit voltage Voc, and the fill factor FF. The increase in the contact resistance appears particularly as a decrease in the FF characteristics.

[0145] The applicant investigated the correlation between the acetic acid concentration and the FF characteristics and obtained a correlation as shown in FIG. 13. FIG. 13 is a graph showing the relationship between the acetic acid concentration and the FF change rate (deterioration rate) for the PV modules subjected to the damp heat test (damp heat test samples) and the PV modules recovered from the field (market recovered products).

[0146] As shown in Figure 13, it can be seen that the FF characteristics deteriorate rapidly when the acetic acid concentration exceeds a certain level. There are several deterioration modes that affect the lifespan of a PV module. Among these, the rapid deterioration of the FF characteristics due to electrode corrosion caused by acetic acid (lifespan deterioration due to moist heat stress) is an extremely important deterioration mode that determines the upper limit of the lifespan of a PV module. Here, an FF characteristic deterioration rate of 10% is taken as the guideline for the moist heat deterioration lifespan, and the acetic acid concentration at this time is referred to as the acetic acid concentration at lifespan A. T The acetic acid concentration at the end of life is A T It is considered appropriate to assume that the range of is approximately the range shown in the following equation (33). Lifetime Acetic Acid Concentration A T ≒ 3 × 10 18 ~ 3×10 19 [ / cm 3 ] (33)

[0147] In addition, the acetic acid concentration at the end of life A T The PV module is subjected to a damp heat test until the end of its life, and the acetic acid concentration information A at the end of its life is T may be given by measuring

[0148] Here, the lifetime acetic acid concentration A T can vary depending on the specifications of the PV module. In other words, the lifetime acetic acid concentration A varies depending on the specifications of the electrodes of the solar cell in the PV module (composition, electrode width, electrode thickness, firing conditions, etc.) and / or the specifications of the sealing material in the PV module (main material, additives, thickness, etc.). T may be set to an appropriate value. In this case, the lifetime acetic acid concentration A T is not limited to the range of the above formula (33), and upper and lower limit values ​​may be given according to the specifications of the PV module. Specifically, a damp heat test and / or a UV damp heat combined test (for example, a UV damp heat sequential combined test in which a damp heat test is performed after a UV test) may be performed for each specification of the PV module. Then, a graph such as that shown in FIG. 13 is created for each specification of the PV module, and an appropriate lifetime acetic acid concentration A T (a new range to replace the range shown in equation (33)) may be determined.

[0149] <Calculation of the service life of the PV module> Next, as shown in step S7 of FIG. 4, the control unit 10 of the electronic device 1 calculates the number of years (service life Y T ) until the service life based on the deterioration of the PV module to be predicted due to damp heat.

[0150] Based on the above, the number of years until the service life based on the deterioration of the PV module due to damp heat (hereinafter, simply referred to as service life Y T is also denoted) has the following relationship with the acetic acid concentration A at the above-mentioned service life T and the following formula (34). A T = A0·exp(B0·exp(-qEa / kTeff)·Heff·365·Y T ) (34)

[0151] Here, A0 represents the acetic acid concentration in the EVA of the PV module at a predetermined time point. Also, Y T is the number of years until the service life (unit: [Y (year)]) with the time point when the acetic acid concentration in the EVA of the PV module was A0 as the zero time point. Also, B0 can be 1.6×10 7 as in the case of the above formula (17).

[0152] Solving the above formula (34) for Y T yields the following formula (35). Y T = ln(A T / A0) / {B0·exp(-qEa / kTeff)·Heff·365} (35)

[0153] Here, considering that the acetic acid concentration A at the service life can have a distribution width of about 3×10 T ~ 3×10 18 ~ 3×10 19 [ / cm 3 , a distribution width can also be given to the service life Y T . Specifically, the value of the service life Y T obtained when the acetic acid concentration A at the service life is 3×10 18 is taken as the service life Y T ​T This can be used as a guideline for the lower limit of the acetic acid concentration A at the end of the lifespan. T 3×10 19 The life expectancy Y obtained when T The value of T This can be used as a guideline for the upper limit.

[0154] FIG. 14 shows the life span Y obtained by the above formula (35). T 14 is a graph showing the actual lifespan of a PV module installed in the field (market installed product) together with the lifespan Y T The upper limit of the predicted remaining life is indicated by a dashed line (predicted remaining life (upper limit)). In addition, in FIG. 14, the life span Y T The lower limit of the predicted remaining life is indicated by a dashed line (lower limit). In FIG. 14, the products installed in the market are indicated by black circles (●).

[0155] In Figure 14, the life span Y T is calculated with the time when the PV module was installed in the field as the zero point of time. T 3×10 18 [ / cm 3 ] as the life span Y T The calculation was performed assuming the lower limit of the acetic acid concentration A T 3×10 19 [ / cm 3 ] as the life span Y T As shown in FIG. 14, the actual lifespan of the PV module is between the lower and upper limits of the predicted lifespan, and the lifespan Y T The validity of the can be confirmed.

[0156] <Humidity and UV correction in life prediction> In this way, the life span Y T This life span Y Tcan be regarded as a guideline for the lifespan years before considering humidity correction (humidity dependence of the time to lifespan due to moist heat) and UV correction (UV light dependence of the time to lifespan due to moist heat). If the risk of deterioration until the approximate future lifespan of the target PV module is to be evaluated, the guideline lifespan years can be said to be sufficiently useful information, as shown in Figure 14. On the other hand, if it is desired to obtain a more accurate lifespan of the target PV module, the humidity correction and UV correction described below may be considered.

[0157] When performing humidity correction and UV correction, the control unit 10 of the electronic device 1 may calculate a humidity correction coefficient as shown in step S8 of Fig. 4, and may calculate a UV correction coefficient as shown in step S9. In this way, the control unit 10 calculates the life span Y T That is, the lifespan based on deterioration due to UV and moist heat in the installed field can be calculated.

[0158] Here, the humidity correction is a correction made to B0 in the above formulas (34) and (35). Also, the UV correction is a correction made to A0 in the above formulas (34) and (35). Specifically, if the humidity correction coefficient is represented as βH and the UV correction coefficient is represented as βU, the above formulas (34) and (35) can be expressed as the following formulas (36) and (37). A T =(A0·βU)·exp((B0·βH)·exp(-qEa / kTeff)·Heff·365·Y T ) (36) Y T =ln(A T / (A0·βU)) / {(B0·βH)·exp(-qEa / kTeff)·Heff·365} (37)

[0159] In the above formulas (36) and (37), the humidity correction coefficient βH can be given in the range of about 0.5 to 1, and the UV correction coefficient βU can be given in the range of 1 to about 20. Below, the humidity correction coefficient and the UV correction coefficient will each be described in further detail.

[0160] <About humidity correction coefficient> The humidity correction coefficient βH is a parameter for taking into account the humidity dependency of B0. This parameter is 1.6×10 7 By multiplying by the humidity correction coefficient βH, the moisture concentration in the EVA when installed in the actual field (under the humidity conditions in the field) [H 2 The humidity correction coefficient βH can be given in the range of about 0.5 to 1 as described above. The moisture concentration in the EVA [H 2 As mentioned above, the moisture concentration in EVA [H 2 O] may be information that should be determined experimentally. Therefore, the humidity correction coefficient βH may also be information that should be determined experimentally.

[0161] The applicant has confirmed through experiments conducted to date that the lifespan of a PV module based on deterioration due to moist heat depends on the relative humidity. The applicant has also confirmed that the relative humidity at the temperature of a PV module can be obtained by taking into consideration information on the relative humidity of the atmosphere in an actual field environment and information on the temperature of a PV module installed at that location. The applicant has also confirmed that the moist heat lifespan of a PV module in an actual field can be obtained by the following procedure.

[0162] That is, first, the Arrhenius equation is applied to the moist heat life of the PV module in the high temperature and high humidity test. This determines the moist heat life under high humidity conditions (same relative humidity conditions as the high temperature and high humidity test) at the actual field temperature. Next, a predetermined humidity correction coefficient (determined based on the relative humidity information at the temperature of the PV module in the actual field environment) is applied to this moist heat life under high humidity conditions. This allows the moist heat life of the PV module in the actual field environment to be obtained.

[0163] At this time, the applicant derived that a value of around 2 at most is appropriate as the humidity correction coefficient in life prediction from the results of the damp heat test with the relative humidity condition as a variable. The humidity correction coefficient in life prediction is in an inverse relationship with βH, which is the correction coefficient of the coefficient B0 of the acetic acid generation reaction. From the above, a value in the range of about 0.5 to 1 as described above was obtained as the humidity correction coefficient βH.

[0164] In the PV module installed in the actual field, the value to be specifically adopted within the above range as the humidity correction coefficient βH may be determined by comprehensively judging from the accumulation of predetermined information. Here, the predetermined information may be, for example, the analysis value of the moisture concentration in EVA by recovering the PV module installed in the field. Also, the predetermined information may be the remaining period (life time) until the life obtained by performing an additional damp heat test on the PV module installed in the field. If it is considered that there is insufficient information necessary or sufficient for comprehensive judgment, a value as close to 1 as possible may be adopted as the humidity correction coefficient βH. This corresponds to predicting the life years of the PV module relatively strictly, that is, estimating it to be short. By such a prediction, when the user makes a judgment based on the life years of the PV module, a safer choice can be prioritized over a choice including risks caused by predicting the life years of the PV module to be longer. How close the humidity correction coefficient βH is to 1 may be determined based on the risk policy of the entity judging the life years of the PV module. Also, for example, in the southern region of Japan in particular, and in regions with relatively high humidity throughout the year such as Southeast Asia, a value close to 1 can be adopted as the humidity correction coefficient βH.

[0165] <Regarding the UV correction coefficient> The UV correction coefficient βU is a parameter that takes into consideration the phenomenon in which additives in EVA are involved in the generation of acetic acid when UV light is present. A representative additive involved in the generation of acetic acid under the stress of UV light is UVA (UV absorber). The UV correction coefficient βU may be determined by considering the UV light transmission characteristics of the glass located on the light incident surface of the PV module, the presence or absence and the concentration of additives in the EVA, and the number of years the PV module has been installed. Here, the maximum value of the UV correction coefficient βU can be obtained as follows. That is, first, the acetic acid concentration at which the acetic acid concentration generated when a PV module after manufacture but before installation in the field is put into a UV irradiation test is approximately saturated (e.g., 2×10 18 / cm 3 In this case, the cumulative irradiation energy of UV light in the UV irradiation test is set at 300 kWh / m, assuming that the device has been installed in the field for about three years. 2 Next, the acetic acid concentration thus obtained may be adjusted to the acetic acid concentration before the UV irradiation test (for example, 1 to 2 × 10 17 / cm 3 The maximum value of the UV correction factor βU can be obtained by dividing the UV correction factor βU by the acetic acid concentration (e.g., 2×10 18 / cm 3 The acetic acid concentration before installation in the field (e.g., 1–2 × 10 17 / cm 3 From the above, the UV correction coefficient βU can be given in the range of 1 to about 20, as described above.

[0166] Below, the method of determining the UV correction coefficient βU will be explained for several cases.

[0167] First, when the glass located on the light incident surface of the PV module is glass that hardly transmits UV light (UV-cut glass), the UV correction coefficient βU may be given a value close to 1. This is because, in the case of UV-cut glass, even if additives such as the ultraviolet absorber UVA are blended into the EVA, almost no UV light reaches the EVA, so there is almost no acetic acid production caused by the additives involving UV light.

[0168] Next, in the case where the glass located on the light incident surface of the PV module is a glass that transmits UV light (UV through glass) and the installation period is about 3 years or more, the UV correction coefficient βU may be given a value close to 1 regardless of the presence or absence of additives such as UVA. This is because even if additives such as the ultraviolet absorber UVA are added, the reaction that generates acetic acid due to these and UV light hardly occurs when the PV module is installed for about 3 years. Specifically, this is because additives such as the ultraviolet absorber UVA are decomposed or bonded with other molecules due to UV light stress within about 3 years after installation, and their concentration rapidly decreases in inverse proportion to the generation of acetic acid.

[0169] Next, when the glass located on the light incident surface of the PV module is UV-through glass, an additive such as an ultraviolet absorber UVA is blended into the EVA, and the PV module has been installed for less than approximately three years, the UV correction coefficient βU may be in the range of 1 to a maximum of approximately 20. For example, the shorter the age of the PV module, the closer the UV correction coefficient βU to 20, and the closer the age of the PV module is to approximately three years, the closer the UV correction coefficient βU to 1.

[0170] More specifically, the UV correction coefficient βU may be given according to the amount of additive added. For example, when UVA is added, if the amount of UVA added is U1 and the concentration of acetic acid in EVA is A0, βU may be given by the following formula (38). βU=1~U1 / A0 (38)

[0171] In addition, when UVA is not added, if the concentration of acetic acid in EVA when it reaches near saturation in the UV irradiation test is U2, βU may be given by the following equation (39): βU=1~U2 / A0 (39)

[0172] <When predicting remaining life using Raman measurement information> Next, a case where the remaining life of a PV module is predicted using Raman measurement information (Raman signal intensity) will be described.

[0173] First, we will describe the case where the glass located on the light incident surface of the PV module is glass that barely transmits UV light (UV-cut glass). In this case, the relationship between the Raman signal intensity ratio and the acetic acid concentration is as shown in Figure 6, and the acetic acid concentration in the EVA can be obtained from the Raman signal intensity ratio. This is because, in the case of UV-cut glass, even if additives such as the ultraviolet absorber UVA are blended into the EVA, almost no UV light reaches the EVA, so there is almost no acetic acid generation caused by the additives.

[0174] Next, the case where the glass located on the light incident surface of the PV module is a glass that transmits UV light (UV through glass) will be described. In this case, the relationship between the Raman signal intensity ratio and the acetic acid concentration may be significantly different from the correlation shown in FIG. 6. That is, the correlation may have a different slope from the correlation shown in FIG. 6. Specifically, as the relationship between the Raman signal intensity ratio and the acetic acid concentration, for example, the correlation shown in FIG. 15 may be obtained. In such a case, a correction coefficient γ may be introduced so that the acetic acid concentration in the EVA can be correctly calculated from the Raman signal intensity ratio. That is, when the correlation shown in FIG. 6 is expressed by the following formula (40), the correlation when the slope is significantly different from the correlation in FIG. 6 (for example, the correlation shown in FIG. 15) can be given by the following formula (41) using γ. log(acetic acid concentration [μg / g]) = C1 × Raman signal intensity ratio + C2 (40) log(acetic acid concentration [μg / g]) = γ C1 × Raman signal intensity ratio + C2 (41) C1 in the above formula (40) represents the slope of the approximation equation that fits the experimental data in the graph of [log(acetic acid concentration)-Raman signal intensity ratio] shown in FIG. 6. C2 in the above formula (40) represents the intercept of the approximation equation that fits the experimental data in the graph of [log(acetic acid concentration)-Raman signal intensity ratio] also shown in FIG. 6. γ in the above formula (41) is a correction coefficient that corrects C1 (i.e., replaces the slope with γ·C1) that gives the slope of the approximation equation that fits the experimental data shown in FIG. 6. By introducing the correction coefficient γ, an approximation equation that fits the experimental data, for example, as shown in FIG. 15, can be obtained. The value of γ can be in the range of 0.2 to 1.0. For example, in the examples of FIG. 6 and FIG. 15, C1 can be about 3.12±0.03, C2 can be about 1.41±0.02, and γ can be about 0.23±0.04.

[0175] When the glass located on the light incident surface of the PV module is a glass that transmits UV light (UV-through glass), the absolute value of the Raman signal intensity may be very large, and the Raman signal intensity ratio may take a form such as that shown in Figure 16. This phenomenon is particularly noticeable when the ultraviolet absorber UVA is added. Here, the Raman signal intensity ratio is calculated by dividing a given Raman signal intensity by the Raman shift of 2800 cm -1 The Raman signal intensity ratio is normalized by the Raman signal intensity caused by nearby CH. Hereinafter, a method for calculating the remaining life years of a PV module when a Raman signal intensity ratio such as that shown in Fig. 16 is obtained will be described.

[0176] First, the case where the installation years (Y0 years) of the PV module are about 3 years or more (when about 3 years < Y0 years) will be described. When the installation years of the PV module are about 3 years or more, as described above, the concentration of additives such as the ultraviolet absorber UVA has already significantly decreased. Therefore, the generation of acetic acid caused by these additives can be almost ignored thereafter. Thus, in the PV module whose installation years are about 3 years or more, when the Raman spectrum waveform as shown in FIG. 16 is observed, it may be considered that the acetic acid concentration caused by these additives has reached saturation at about 3 years after installation. That is, when the time point about 3 years after the installation of the PV module is taken as the reference time (zero year), the acetic acid concentration A T and / or the years to the end of life (remaining life years) Y T can be obtained using Equations (36) and (37). In this case, 1 is used as the value of βU, and 1 to 2×10 18 is used as the reference value of A0 at the reference time. Alternatively, 1 can be used as the value of βU, and the above-mentioned U1 or U2 can be used as the reference value of A0 at the reference time. From the above, the years to the end of life (remaining life years) at the time of Y0 years is Y T +(3 - Y0).

[0177] Next, a case where the installation age (Y0) of the PV module is less than about 3 years at that time (Y0<about 3 years) will be described. When the installation age of the PV module is less than about 3 years at that time, the concentration of additives such as the ultraviolet absorber UVA has not yet decreased significantly. However, unless there is a particular reason to remove it, the PV module will generally continue to be installed in the same place thereafter, and the installation age will exceed about 3 years, and will continue to be installed for a long period of time. In this way, when it is expected that the installation age will exceed about 3 years in the future, the situation is the same as when the installation age is about 3 years or more. That is, when it is expected that a Raman spectrum waveform such as that shown in FIG. 16 will be obtained in the future for a PV module that has been installed for less than about 3 years (Y0), the remaining life of the PV module may be predicted as follows. That is, when the installation age of the PV module is about 3 years as the reference time (zero year), the acetic acid concentration A T and / or number of years until life expectancy Y T can be calculated using equations (36) and (37). In this case, 1 is used as the value of βU, and 1 to 2×10 is used as a guideline for the value of A0 at the reference time. 18 Alternatively, βU may be set to 1, and the above-mentioned U1 or U2 may be used as the reference value of A0 at the reference time. From the above, the number of years until the end of life (remaining life years) at the time of Y0 is Y T +(3-Y0).

[0178] <Relationship between predicted lifespan based on deterioration due to heat and humidity and actual lifespan> The lifespan (predicted remaining lifespan) of a PV module based on deterioration due to damp heat obtained by the above procedure has a magnitude relationship with the actual lifespan, as shown in the following equation (42). Actual life expectancy <= Life expectancy based on heat and humidity deterioration (42)

[0179] The reason why the relationship shown in the above formula (42) is obtained is because the actual remaining life years are not only caused by the environmental stresses of temperature, humidity, and UV light, but also by all environmental stresses such as temperature cycle stress and / or potential difference stress. Here, the potential difference stress is a stress caused by the potential difference between the PV module and the ground potential. Therefore, the life years based on the deterioration due to moist heat obtained by the electronic device 1 according to an embodiment may be interpreted as giving an upper limit of the actual life years. That is, the life years based on the deterioration due to moist heat of the PV module obtained by the electronic device 1 according to an embodiment is a value obtained with a certain range depending on how the acetic acid concentration at the time of the life, the humidity correction coefficient, and / or the UV correction coefficient are given. However, taking into consideration the magnitude relationship with the actual life years described above, the shorter life years among the life years obtained with a range may be weighted and regarded as a predicted value. With such a prediction, when a user makes a decision based on the life years of the PV module, a safer choice can be prioritized over a choice that includes a risk caused by predicting the life years of the PV module to be longer.

[0180] Furthermore, if the total lifespan of the panel is denoted as Ytotal, Ytotal can be expressed as follows: Ytotal = installation years + remaining life years = Y0 + Y T (43) However, the total lifespan Ytotal mentioned here is only meaningful when there is no change in the installation area / installation form before and after the measurement of the acetic acid concentration.

[0181] <Effects of the Electronic Device According to the Embodiment> According to the electronic device 1 of an embodiment, the life (remaining life) due to subsequent deterioration due to moist heat can be predicted based on information indicating the acetic acid concentration in the EVA in the PV module. According to the electronic device 1 of an embodiment, when the acetic acid concentration is obtained by Raman measurement, the life (remaining life years) of the target PV module due to deterioration due to moist heat can be predicted based only on Raman measurement information at a single time. According to the electronic device 1 of an embodiment, even if the installation form and / or installation location of the PV module is changed, the life (remaining life years) of the changed PV module due to deterioration due to moist heat can be predicted. In this case, if there is acetic acid concentration information at the time of change (if there is Raman measurement information at the time of change), the life (remaining life years) of the changed PV module due to deterioration due to moist heat can be predicted.

[0182] In recent years, a secondary market (buying and selling market) for PV power plants is emerging. A business scheme with a guarantee for used PV modules has also appeared there. In this situation, when trading used PV modules at a fair price, the issue of how to evaluate the asset value of the used PV module at the present time is extremely important, and the evaluation technology is very important. According to the electronic device 1 of an embodiment, the time remaining until the end of the life of the used PV module can be evaluated rationally. Therefore, the evaluation of the asset value of the used module by the electronic device 1 of an embodiment can be an essential technology in such a business scheme. According to the electronic device 1 of an embodiment, it is possible to provide information on the time remaining until the end of the life of the PV module as highly reliable information in the secondary market for PV power plants.

[0183] In addition, in recent years, the problem of final disposal (disposal) of existing residential PV modules has begun to be recognized. Specifically, the time until the disposal of the PV module (remaining life years), the inspection method during the period until disposal, and / or the final disposal method have begun to be recognized as issues. According to the electronic device 1 of an embodiment, the period until the end of the life of an existing residential PV module can be reasonably evaluated. Therefore, the evaluation of the remaining life years of an existing module by the electronic device 1 of an embodiment can be an essential technique for making an appropriate decision on such issues. According to the electronic device 1 of an embodiment, in an existing residential PV module, information regarding the period until the end of the life of the PV module (remaining life years) can be provided as highly reliable information.

[0184] According to the electronic device 1 of the embodiment, it is possible to reasonably predict the remaining life of a PV module that employs a general EVA as an encapsulant. On the other hand, for a PV module that uses an EVA to which an acid acceptor has been added, the remaining life may be predicted by taking into account parameters other than the various parameters described above.

[0185] Although the present disclosure has been described based on the drawings and examples, it should be noted that a person skilled in the art can easily make various modifications or corrections based on the present disclosure. Therefore, it should be noted that these modifications or corrections are included in the scope of the present disclosure. For example, the functions included in each functional unit can be rearranged so as not to be logically inconsistent. Multiple functional units, etc. may be combined into one or divided. Each embodiment of the present disclosure described above is not limited to being implemented faithfully to each of the embodiments described, and may be implemented by combining each feature as appropriate or omitting a part. In other words, the contents of the present disclosure can be modified and corrected in various ways by a person skilled in the art based on the present disclosure. Therefore, these modifications and corrections are included in the scope of the present disclosure. For example, in each embodiment, each functional unit, each means, each step, etc. can be added to other embodiments so as not to be logically inconsistent, or replaced with each functional unit, each means, each step, etc. of other embodiments. In addition, in each embodiment, multiple functional units, each means, each step, etc. can be combined into one or divided.

[0186] The above-described embodiment is not limited to being implemented only as an electronic device. For example, the above-described embodiment may be implemented as a control method for an apparatus such as an electronic device. Furthermore, for example, the above-described embodiment may be implemented as an apparatus such as an electronic device or a program executed by a computer, or as a storage medium or recording medium on which such a program is recorded. [Explanation of symbols]

[0187] 1 Electronic equipment 10 Control section 20 Input section 30 Output section 40 Communications Department 50 Storage section

Claims

1. First information representing an acetic acid concentration in an encapsulant of the solar cell module at a predetermined time; Second information representing an acetic acid concentration in the sealing material at the end of a period during which the solar cell module is capable of outputting a predetermined amount of power; and Based on third information related to calculation of a change over time in the concentration of acetic acid in the encapsulant in the usage environment of the solar cell module, The electronic device generates fourth information regarding a remaining period during which the solar cell module is expected to be able to output the specified power in the usage environment.

2. The electronic device according to claim 1 , wherein the first information is information obtained by destroying the solar cell module.

3. The electronic device according to claim 1 , wherein the first information is information obtained based on an analysis of an encapsulant of the solar cell module by an ion chromatography method.

4. The electronic device according to claim 1 , wherein the first information is information acquired based on a pH measurement performed on a sealing material of the solar cell module.

5. The electronic device according to claim 1 , wherein the third information is information representing a time transition of an acetic acid concentration in the sealing material.

6. The electronic device according to claim 1 , wherein the fourth information is information relating to a period before a sudden drop in power output by the solar cell module in the usage environment occurs.

7. The electronic device according to claim 1 , wherein the fourth information is generated based on the first information, the second information, and the third information, and also by taking into account a correction related to humidity to which the solar cell module is exposed.

8. The electronic device according to claim 1 , wherein the fourth information is generated based on the first information, the second information, and the third information, and also by adding a correction related to ultraviolet light to which the solar cell module is exposed.

9. Obtaining first information representing an acetic acid concentration in an encapsulant of a solar cell module at a predetermined time point; acquiring second information representing a concentration of acetic acid in the sealing material at the end of a period during which the solar cell module is capable of outputting a predetermined amount of power; acquiring third information related to calculation of a change over time in the concentration of acetic acid in the sealing material in a usage environment of the solar cell module; generating fourth information regarding a remaining period during which the solar cell module is expected to be able to output the predetermined power in the usage environment based on the first information, the second information, and the third information; A method for controlling an electronic device, comprising:

10. For electronic devices, Obtaining first information representing an acetic acid concentration in an encapsulant of a solar cell module at a predetermined time point; acquiring second information representing a concentration of acetic acid in the sealing material at the end of a period during which the solar cell module is capable of outputting a predetermined amount of power; acquiring third information related to calculation of a change over time in the concentration of acetic acid in the sealing material in a usage environment of the solar cell module; generating fourth information regarding a remaining period during which the solar cell module is expected to be able to output the predetermined power in the usage environment based on the first information, the second information, and the third information; A program to execute.

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