JP5895691B2 - Solar cell evaluation apparatus and method - Google Patents

Description

  The present invention relates to a solar cell evaluation apparatus and a solar cell evaluation method for evaluating a solar cell, and in particular, a solar cell that can appropriately evaluate a solar cell that requires time until a stable state is reached after the start of monochromatic light irradiation. The present invention relates to an evaluation apparatus and a solar cell evaluation method.

  A solar cell is an element that directly converts light energy into electric power by utilizing the photovoltaic effect, and various solar cells have been researched and developed, and have begun to spread widely in recent years. This solar cell (hereinafter abbreviated as “PV” as appropriate) includes silicon PV using silicon (Si), compound PV using a compound semiconductor such as InGaAs, and organic PV using an organic semiconductor. There are various types of organic PV, PN junction type PV that uses two types of organic semiconductors to form a PN junction and obtains photoelectromotive force by photoexcitation of electrons in the PN junction, and photoexcitation of electrons in organic dyes. And a dye-sensitized solar cell that obtains a photovoltaic power.

  Among such various solar cells, there is a solar cell that outputs an output current having a stable current value (substantially constant current value) immediately after irradiation with light, for example, represented by silicon PV. For example, as shown in FIGS. 7 and 8, represented by organic PV, the output current gradually increases with the passage of light irradiation time (transient state), and eventually becomes saturated and stable. There is a (steady state) solar cell.

  In order to properly evaluate such a solar cell that does not enter a steady state immediately after light irradiation, it is necessary to evaluate the solar cell in the steady state, and light irradiation called light soaking is evaluated. It is performed on the solar cell before (for example, see Non-Patent Document 1 and Non-Patent Document 2).

  The light soaking effect is not lost immediately after the light soaking light irradiation is stopped, but gradually lost as shown in FIG. For this reason, when light irradiation is performed to evaluate the solar cell after the light soaking light irradiation is stopped, the output current output from the solar cell gradually increases with time as shown in FIG. To drop.

  FIG. 7 is a diagram for explaining the effect of light soaking on the irradiation of white light, the horizontal axis is elapsed time, and the vertical axis is PV output current. FIG. 8 is a diagram showing actual measurement results for showing the effect of light soaking. The solid line shows the output current (mA), and the broken line shows the voltage (mV). The horizontal axis in FIG. 8 is the elapsed time, the vertical axis on the right side of the paper is the voltage, and the vertical axis on the left side of the paper is the current.

  The spectral sensitivity of a solar cell, which is one of the evaluation indexes for evaluating the performance of a solar cell, is the photoelectric conversion efficiency at each wavelength of incident light, and is usually expressed in units of A / W (ampere / watt). The Spectral sensitivity can be measured by irradiating the target solar cell with monochromatic light of the wavelength to be measured and dividing the output current of the solar cell by the energy of the monochromatic light irradiated. A phenomenon similar to that of light soaking is observed even when the monochromatic light irradiated to the solar cell is used to measure the spectral sensitivity. Therefore, the spectral sensitivity of the solar cell needs to be measured after it has stabilized after the start of monochromatic light irradiation.

"Dye-sensitized solar cell performance evaluation method", published by Japan Optical Industry Promotion Association, established in March 2009 Refer to 10.19.3 Procedure in “Thin-Film Thin Film Solar Cell (PV) Module-Requirements for Design Qualification Test and Type Certification”, JIS C 8991, 2011

  By the way, when evaluating a solar cell, determination of whether the solar cell is in the steady state is conventionally performed empirically. For example, the determination is performed by performing an evaluation process a plurality of times after starting a monochromatic light irradiation for spectral sensitivity measurement, and an operator determining whether or not the evaluation results are substantially equal. It has been broken. As a result, when each evaluation result is not substantially equal, various countermeasures such as a countermeasure for increasing the predetermined time after starting the monochromatic light irradiation are taken empirically.

  Thus, evaluation of the solar cell which will be in a steady state through a transient state is performed empirically, and it is difficult to guarantee the reliability of the evaluation result. Moreover, in order to obtain an evaluation result, it is necessary to perform the process a plurality of times, and it takes time to evaluate the solar cell.

  The present invention has been made in view of the above circumstances, and its object is to evaluate solar cells that require time until the output current is stabilized after the start of monochromatic light irradiation with higher reliability and less effort. It is providing the solar cell evaluation apparatus and solar cell evaluation method which can be performed.

  As a result of various studies, the present inventor has found that the above object is achieved by the present invention described below. That is, the solar cell evaluation device according to one aspect of the present invention includes an evaluation light irradiation unit that irradiates a solar cell to be evaluated that needs to be irradiated with monochromatic light for a predetermined time before evaluation, with the monochromatic light having a predetermined wavelength, A detection unit that detects the output of the solar cell when receiving monochromatic light, and an output detected by the detection unit from the start of the irradiation of the monochromatic light by the evaluation light irradiation unit, and monitors the output at a predetermined time. A slope obtained by dividing an output change amount of the solar cell by the predetermined time, or an output detected by the detection unit when a time derivative in the output of the solar cell is within a predetermined range, and the monochrome And a spectral sensitivity calculating unit that calculates the spectral sensitivity of the predetermined wavelength based on the irradiation energy of light.

  When the solar cell evaluation apparatus having such a configuration obtains the spectral sensitivity, which is an evaluation of a solar cell that needs to be irradiated with monochromatic light for a predetermined time before the evaluation, the output change amount of the solar cell during the predetermined time is calculated as the predetermined amount. When the slope divided by time or the time derivative in the output of the solar cell is within a predetermined range, that is, when the output is in a steady state, the output of the solar cell is detected, and based on the output Obtain spectral sensitivity. Therefore, it is possible to evaluate a solar cell that needs to be irradiated with monochromatic light for a predetermined time before evaluation with higher reliability, and to perform evaluation with less effort.

  In another aspect, in the above-described solar cell evaluation apparatus, the evaluation light irradiation unit can irradiate a plurality of single-color lights having different wavelengths, and the plurality of single colors by the evaluation light irradiation unit. Each time from the start of irradiation of each light to the slope obtained by dividing the output change amount of the solar cell at a predetermined time by the predetermined time, or the time derivative at the output of the solar cell is within a predetermined range. A storage unit that stores time in association with the wavelengths of the plurality of monochromatic lights, and the spectral sensitivity calculation unit is configured to start the irradiation of the monochromatic light by the evaluation light irradiating unit. Spectral sensitivity is calculated using the output detected by the detection unit after the elapse of the time stored in association with the wavelength.

  Since the solar cell evaluation apparatus having such a configuration stores, for each wavelength, the time until the output of the solar cell detected by the detection unit is in a steady state, irradiation with monochromatic light for a predetermined time before the evaluation is performed. When obtaining the spectral sensitivity, which is the evaluation of the required solar cell, after irradiating the monochromatic light of a predetermined wavelength for the time stored according to the wavelength, the output of the solar cell is detected, and the spectral sensitivity based on the output You can ask for. Therefore, by setting the irradiation time so that the spectral sensitivity with the accuracy desired by the user can be determined, it is possible to more reliably obtain the spectral sensitivity by monochromatic light for each wavelength in a state where the solar cell is in a steady state. Therefore, it is possible to evaluate a solar cell that needs to be irradiated with monochromatic light for a predetermined time before evaluation with higher reliability, and to perform evaluation with less effort.

  According to another aspect, in the above solar cell evaluation device, the spectral sensitivity calculation unit is configured to emit the monochromatic light having a wavelength different from that of the plurality of monochromatic lights by the evaluation light irradiation unit. Based on the wavelength associated with the wavelength of the emitted monochromatic light and the time associated with the wavelength among the wavelengths of the monochromatic light stored in the storage unit, the wavelength of the emitted monochromatic light is changed. And calculating the spectral sensitivity using the output detected by the detection unit after the calculated time has elapsed from the start of the irradiation of the monochromatic light by the evaluation light irradiation unit.

  In another aspect, in the above-described solar cell evaluation device, the spectral sensitivity calculation unit is irradiated by the evaluation light irradiation unit among the wavelengths of the plurality of monochromatic lights stored in the storage unit. Based on the wavelength before and after the wavelength of the monochromatic light and the time associated with the wavelength, the time corresponding to the wavelength of the monochromatic light to be irradiated is calculated by interpolation.

  In another aspect, in the above-described solar cell evaluation device, the spectral sensitivity calculation unit is irradiated by the evaluation light irradiation unit among the wavelengths of the plurality of monochromatic lights stored in the storage unit. Based on the wavelength belonging to the wavelength range including the wavelength of the monochromatic light and the time associated with the wavelength, a relational expression between the wavelength and the time is obtained, and according to the wavelength of the monochromatic light irradiated by the relational expression. Time is calculated.

  Even if the solar cell evaluation apparatus having such a configuration does not measure the time until the output of the solar cell detected by the detection unit is in a steady state, the solar cell evaluation device has a steady state based on the measured wavelength and time. The time to become can be obtained. Therefore, it is possible to obtain spectral sensitivity at a finer pitch than the wavelength pitch at which the time until the steady state is measured, and to perform evaluation with higher reliability with less effort.

  According to another aspect, in the above-described solar cell evaluation device, the evaluation light irradiating unit can irradiate a plurality of monochromatic lights having different wavelengths, and the spectral sensitivity calculation unit is configured to output the evaluation light. Spectral sensitivity is calculated using the output detected by the detection unit after the elapse of a specific time from the start of irradiation of the monochromatic light by the irradiation unit, and the specific time is a plurality of single colors irradiated by the evaluation light irradiation unit Among the lights, the inclination obtained by dividing the output change amount of the solar cell at a predetermined time by the predetermined time from the start of irradiation of the representative monochromatic light, or the time derivative at the output of the solar cell is within a predetermined range. The representative monochromatic light is a monochromatic light having the longest wavelength among a plurality of monochromatic lights irradiated by the evaluation light irradiation unit.

  The solar cell evaluation device having such a configuration stores the time if the monochromatic light having a wavelength shorter than the wavelength storing the time until the output of the solar cell detected by the detection unit reaches a steady state. Since the spectral sensitivity due to the short-wavelength monochromatic light can be accurately obtained, the evaluation can be performed with higher reliability with less effort.

  The solar cell evaluation apparatus and solar cell evaluation method according to the present invention can evaluate solar cells that require time until the output is stabilized after the start of monochromatic light irradiation with higher reliability and less effort.

It is a figure for demonstrating transition of the output current at the time of irradiating a monochromatic light to a solar cell. It is a figure which shows the evaluation time of the solar cell at the time of changing the waiting time after monochromatic light irradiation start for every monochromatic light to irradiate. It is a figure which shows the structure of the solar cell evaluation apparatus of the solar cell in embodiment. It is a flowchart which shows the spectral sensitivity measurement process of the solar cell of a solar cell evaluation apparatus. It is a flowchart which shows the modification 1 of the spectral sensitivity measurement process of a solar cell evaluation apparatus. It is a flowchart which shows the modification 2 of the spectral sensitivity measurement process of a solar cell evaluation apparatus. It is a figure for demonstrating the effect of the light soaking with respect to irradiation of white light. It is a figure which shows the actual measurement result for showing the effect of light soaking.

Hereinafter, an embodiment according to the present invention will be described with reference to the drawings.
<Embodiment>
The solar cell evaluation apparatus for a solar cell in the embodiment measures spectral sensitivity as an evaluation index for evaluating the performance of the solar cell, and shortens the time required for measuring the spectral sensitivity of the solar cell.

  FIG. 1 is a diagram for explaining the transition of the output current when the solar cell PV is irradiated with monochromatic light, the horizontal axis is the elapsed time, and the vertical axis is the output current of the solar cell PV. is there.

  The graph α1 is a graph showing the transition of the output current when the solar cell PV is irradiated with monochromatic light having a wavelength of 450 nm (nanometers), and the graph α2 is a monochromatic light having a wavelength of 700 nm. It is a graph which shows transition of an output current when it irradiates to. In FIG. 1, time t10 indicates the time when monochromatic light irradiation is started, and time t11 indicates the time when the output current is in a steady state when monochromatic light having a wavelength of 450 nm is irradiated. The time t12 indicates the time when the output current is in a steady state when monochromatic light with a wavelength of 700 nm is irradiated.

  As shown in FIG. 1, the output current of the solar cell PV gradually increases with the lapse of the monochromatic light irradiation time, and eventually becomes saturated and becomes a stable current value (steady state). Depending on the time, the time until the steady state is reached differs. Hereinafter, the time from when the monochromatic light irradiation is started until the output current reaches a steady state is referred to as “waiting time after starting monochromatic light irradiation”. That is, the waiting time after the start of monochromatic light irradiation differs for each wavelength of light irradiated to the solar cell.

  Therefore, in the solar cell evaluation apparatus of the embodiment, by changing the timing for measuring the output current of the solar cell PV according to the monochromatic light, the spectral sensitivity is obtained with high reliability, and the measurement time of the spectral sensitivity is shortened. Is.

  FIG. 2 is a diagram for explaining the measurement time (evaluation time) when measuring the spectral sensitivity of the solar cell by changing the timing for measuring the output current of the solar cell PV according to the monochromatic light. The axis is the elapsed time, and the vertical axis is the output current of the solar cell PV. Graphs α3, α4, and α5 are monochromatic lights having different wavelengths, and are graphs showing changes in output current when monochromatic lights having wavelengths λ3, λ4, and λ5 are irradiated to the solar cell PV, respectively.

  Time t20 indicates the time when the irradiation of monochromatic light with wavelength λ3 is started, and time t21 indicates the time when the output current of the solar cell is in a steady state. Time t22 indicates the time when the irradiation of the monochromatic light of wavelength λ4 is started immediately after time t21 and the output current of the solar cell is in a steady state. Time t23 indicates the time when the irradiation of the monochromatic light with the wavelength λ5 is started immediately after time t22 and the output current of the solar cell is in a steady state.

  Thus, at each of the times t21, t22, and t23 at the timing (immediately after) when the steady state is reached, the output current is measured to obtain the spectral sensitivity. The obtained spectral sensitivities are respectively the spectral sensitivities of monochromatic lights having wavelengths λ3, λ4, and λ5.

  That is, since the spectral sensitivity is obtained immediately after the steady state is reached, it is possible to obtain the accurate spectral sensitivity of each monochromatic light in the minimum necessary time.

<Configuration>
Drawing 3 is a figure showing the composition of the solar cell evaluation device of the solar cell in an embodiment. The solar cell evaluation apparatus S for solar cells in the embodiment is an apparatus that evaluates a solar cell PV to be evaluated, which requires a waiting time after the start of monochromatic light irradiation, using a predetermined evaluation item. For example, as shown in FIG. Furthermore, the evaluation light irradiation unit 1, the optical system 2, the detection unit 3, the calculation control unit 4, the input unit 5, the output unit 6, the interface (IF) unit 7, and the storage unit 8 are provided.

  The evaluation light irradiating unit 1 is an apparatus that irradiates evaluation light for performing evaluation on the predetermined evaluation item according to the control of the arithmetic control unit 4. In the present embodiment, since the predetermined evaluation item is the spectral sensitivity of the solar cell, the evaluation light is monochromatic light whose irradiation light energy is known, and the wavelength of the monochromatic light needs to be variable. The variable wavelength band of the monochromatic light includes a wavelength range in which the solar cell PV to be evaluated has sensitivity. For this reason, the evaluation light irradiating unit 1 selects (varies) the wavelength of the monochromatic light, adjusts the emitted light intensity of the monochromatic light, and turns on the monochromatic light according to the control of the arithmetic control unit 4. It is a device having various functions such as a function to turn off. The evaluation light irradiation unit 1 for evaluating with such spectral sensitivity includes, for example, an evaluation light source drive control unit 11, an evaluation light source unit 12, an optical system 13, and a monochromator 14 as shown in FIG. And an optical system 15, a branching optical coupler unit 16, an irradiance detection unit 17, and an amplification unit 18.

  The evaluation light source unit 12 is a light source device that emits light in a predetermined wavelength band including the wavelength of monochromatic light emitted from the monochromator 14, and is, for example, a xenon lamp. Xenon lamps are suitable for measuring spectral sensitivity because they have high brightness and color temperature and emit light in a continuous spectrum over a wide band from ultraviolet to visible to infrared. The evaluation light source drive control unit 11 performs evaluation light such as drive control of emission (lighting) and stop (lighting off) of the evaluation light and adjustment control of the intensity of emitted light of the evaluation light according to the control of the arithmetic control unit 4. It is a device that drives and controls the light source unit 12.

  The optical system 13, the optical system 15, and the optical system 2 are optical elements such as lenses for concentrating or collimating (collimating) light according to the application. The light emitted from the evaluation light source unit 12 according to the control of the evaluation light source drive control unit 11 enters the monochromator 14 via the optical system 13.

  The monochromator 14 converts the light incident from the evaluation light source 12 through the optical system 13 into monochromatic light at a predetermined wavelength according to the instruction (selection) of the arithmetic control unit 4 according to the control of the arithmetic control unit 4. It is a device that injects. The monochromator 14 is, for example, a spectroscope that spatially disperses the light in the predetermined wavelength band and extracts only a narrow range of wavelengths with a slit or the like. Such a monochromator 14 includes, for example, an entrance slit, a first reflecting mirror, a diffraction grating, a second reflecting mirror, and an exit slit, and an incident light beam incident through the entrance slit is transferred to the diffraction grating by the first reflecting mirror. This is a device that reflects the diffracted light of the incident light beam reflected and diffracted by the diffraction grating to the exit slit by the second reflecting mirror. With such a configuration, the monochromator 14 can select the wavelength of light that reaches the slit position by rotating the diffraction grating or the like, and can extract only a wavelength in a desired range (single-color light conversion). The monochromator 14 is controlled by the arithmetic control unit 4 so as to extract the wavelength in the desired range. The monochromatic light emitted from the monochromator 14 is incident on the branch optical coupler unit 16 through the optical system 15.

  The branching optical coupler unit 16 is an optical component that divides incident light into two lights and emits them. The monochromatic light incident on the branching optical coupler unit 16 is distributed by the branching optical coupler unit 16, one of which is incident on the irradiance detection unit 17, and the other is the sun to be evaluated via the optical system 2. The battery PV is irradiated.

  The irradiance detector 17 is a device (reference detector) that measures the irradiance (not the spectral irradiance) of monochromatic light (monochromatic light emitted from the monochromator 14) distributed by the branching optical coupler unit 16. The measurement result is output to the amplifying unit 18. The amplifying unit 18 amplifies the irradiance measured by the irradiance detecting unit 17 with a predetermined amplification factor and outputs the amplified irradiance to the arithmetic control unit 4. When the irradiance of monochromatic light is known by measuring in advance, the irradiance detection unit 17, the amplification unit 18 and the branching optical coupler unit 16 may be omitted.

  The detection part 3 is an apparatus which detects the output of the said solar cell PV according to an evaluation item. In this embodiment, since the predetermined evaluation item is the spectral sensitivity of the solar cell, the detection unit 3 is a device that can understand the voltage and current of the solar cell PV. More specifically, the detection unit 3 can measure the output current of the solar cell PV by applying a voltage having a predetermined voltage value to the solar cell PV according to the control of the arithmetic control unit 4. This is a so-called source meter capable of changing the predetermined voltage value. The detection unit 3 outputs the output of the solar cell detected at a predetermined sampling interval to the calculation control unit 4.

  The input unit 5 is a device for inputting commands (commands), data, and the like from the outside to the solar cell evaluation apparatus S, and is, for example, a keyboard, a mouse, a touch panel, or the like.

  The output unit 6 is a device for outputting commands and data input from the input unit 5 and the calculation result of the calculation control unit 4. For example, the output unit 6 is a display device such as an LCD (liquid crystal display) or an organic EL display, A printing apparatus such as a printer.

  The IF unit 7 is a communication interface for exchanging data between the solar cell evaluation device S and other external devices. For example, the IF unit 7 conforms to a USB (Universal Serial Bus) standard or an RS232C standard. It is a corresponding device.

  The storage unit 8 is an external storage device such as a hard disk device, for example, and stores, for example, detection results of the detection unit 3, programs and data necessary for operation of the calculation control unit 4, calculation results of the calculation control unit 4, and the like. It is.

  In the embodiment, the storage unit 8 stores the entire wavelength range to be measured, the wavelength pitch to be measured, and the irradiation area A of the solar cell PV as data necessary for the spectral sensitivity measurement process. For example, 300 to 1200 nm is stored as the entire wavelength range to be measured, and 5 nm is stored as the pitch. In this case, the number of monochromatic lights to be measured is 181. Further, the measured spectral sensitivity is stored in the storage unit 8.

  The total wavelength range to be measured, the pitch of the wavelength to be measured, and the irradiation area A of the solar cell PV are stored before the evaluation process of the solar cell PV is started. When the irradiance of each monochromatic light is measured and stored in advance, the measured irradiance is also stored before the spectral sensitivity measurement process is started.

  The arithmetic and control unit 4 is an apparatus that controls the entire operation of the solar cell evaluation device S by controlling each unit according to the function, and calculates the evaluation of the solar cell PV. The arithmetic control unit 4 includes, for example, a microprocessor including a CPU (Central Processing Unit), a storage element such as a ROM (Read Only Memory) and a RAM (Random Access Memory), and peripheral circuits thereof. Etc.

  The arithmetic control unit 4 is functionally configured with a spectral sensitivity calculation unit 41 and a change detection unit 42 by executing a program.

  The spectral sensitivity calculation unit 41 is a solar cell stored in the storage unit 8 and the irradiance dE per unit area calculated from the current value dI output from the detection unit 3 and the irradiance output from the amplification unit 18. Spectral sensitivity S (I, λ) = dI (λ) × A / dE (λ) is calculated from the irradiation area A of the monochromatic light irradiated to PV.

  The change detection unit 42 has a function of starting monitoring the output of the detection unit 3 according to an instruction from the calculation control unit 4 and notifying the calculation control unit 4 when the output becomes a steady state.

  Whether or not it is in a steady state depends on whether or not the slope (derivative coefficient) of the tangent line in the curve representing the output current with respect to the elapsed time is within a predetermined range, or the absolute value of the slope (derivative coefficient) of the tangent line is Judgment is made based on whether the value is smaller than a predetermined threshold.

  As the predetermined range, an appropriate range such as a range indicating substantially zero, for example, −0.1 or more and less than 0.1 is set, and the predetermined threshold is a predetermined value close to zero, for example, 0.1 or 0. Appropriate values such as .05 and 0.01 are set. When the differential coefficient is within a predetermined range or when the absolute value is smaller than the predetermined threshold value, it is determined as a steady state, and the tangent slope is not within the predetermined range, or the absolute value is a predetermined threshold value. If it is above, it is determined to be in a transient state.

Further, whether or not it is in a steady state may be determined based on whether or not the gradient obtained by dividing the output change amount of the solar cell PV in a predetermined time by the predetermined time is substantially zero. For example, the output current I of the solar cell PV obtained by the detection unit 3 by the previous sampling (detection) of j−1 from the output current I _j of the solar cell PV obtained by the detection unit 3 by the sampling (detection) of j this time. _j-1 is subtracted, the subtraction result is divided by the sampling interval ΔTs, and the slope of the division result (= (I _j −I _j−1 ) / ΔTs) is within a predetermined range, Alternatively, the determination is made based on whether or not the absolute value of the inclination is smaller than a predetermined threshold. If the slope is within the predetermined range or the absolute value is smaller than the predetermined threshold, it is determined that the state is steady, and if the tangent slope is not within the predetermined range, or the absolute value is greater than or equal to the predetermined threshold. If it is, it is determined that it is in a transient state.

In the embodiment, when the absolute value of the tangent slope (derivative coefficient) is smaller than a predetermined threshold value, it is determined that the solar cell PV is in a steady state (stable), and in other cases, the solar cell PV. Is assumed to be in a transient state (not stable). Further, for example, according to JIS C 8991, in a temperature range of 40 to 60 ° C., an integrated irradiation dose of 43 kWh · m ⁻² or more is regarded as one interval, and measured values in two consecutive intervals are (Pmax−Pmin). ) / Paverag <2% is considered stable. The integrated irradiation amount is obtained based on the irradiance of the monochromatic light emitted from the evaluation light source unit 12, the irradiation area area of the monochromatic light in the solar cell PV, and the number of sampling times (the irradiation time of the monochromatic light in one section). Thus, the output power P of the solar cell PV is obtained based on the applied voltage Vb of the detection unit 3 and the output current I of the solar cell PV obtained by the detection unit 3.

  Note that this determination is made only when the above-described condition for determining that the solar cell PV is in a steady state (stable) is satisfied a plurality of times (for example, three times or five times). It may be determined that the battery PV is in a steady state (stable).

  The numerical value of the determination criterion may be changed according to the accuracy desired by the user, or may be input by the user via the input unit 5. Moreover, the solar cell evaluation apparatus S may be automatically determined from the measurement accuracy defined by the specification. The measurement accuracy in this case varies depending on the current range of the detection unit 3 and the impedance of the measurement circuit system.

  The arithmetic control unit 4 controls the evaluation light source drive control unit 11 and the monochromator 14 to sequentially irradiate the monochromatic light for each pitch stored in the storage unit 8, and when the irradiation is started, the change detection unit 42. When requesting detection of a change in output current and notification from the change detection unit 42 that a steady state has been reached, the spectral sensitivity calculation unit 41 is caused to calculate the spectral sensitivity, and the calculated spectral sensitivity is stored in the storage unit 8. To do.

<Operation>
Next, operation | movement of the solar cell evaluation apparatus S of embodiment is demonstrated. FIG. 4 is a flowchart of processing performed when an evaluation of a certain type of solar cell PV is performed.

  When the operator (user) places the solar cell PV to be evaluated at a predetermined position (step S10) and receives an instruction to start measurement of the first solar cell PV from the input unit 5, the arithmetic control unit 4 To start operation. Thereafter, the arithmetic control unit 4 reads out the entire wavelength range to be measured and the pitch of the wavelength to be measured from the storage unit 8, and the evaluation light source drive control unit 11 so that the evaluation light source unit 12 emits monochromatic light of the first wavelength. The monochromator 14 is controlled (step S11), and the start of monochromatic light irradiation is instructed (step S12). The first monochromatic light to be irradiated is assumed to irradiate monochromatic light having the shortest wavelength in the entire wavelength range to be measured, and sequentially irradiate monochromatic light having a wavelength shifted by the pitch in the long wavelength direction. . In addition, it is good also as irradiating sequentially the monochromatic light of the wavelength shifted | deviated by the pitch from the long wavelength to the short wavelength, and you may determine the order of the monochromatic light to irradiate at random.

  The calculation control unit 4 that has instructed the start of monochromatic light irradiation requests the change detection unit 42 to monitor the change in the output of the detection unit 3. Upon receiving the request, the change detection unit 42 acquires the output current of the solar cell PV detected by the detection unit 3 at a predetermined sampling interval, and whether or not the acquired output current is in a steady state, that is, the tangential slope. It is determined whether or not the absolute value is smaller than a threshold value (step S14).

  If the absolute value of the slope is equal to or greater than the threshold value (step S14: No), the arithmetic control unit 4 determines that it is still in a transient state, and further obtains the output current from the detection unit 3 and makes a determination. When the absolute value of the slope is smaller than the threshold value (step S14: Yes), the calculation control unit 4 determines that it is in a steady state and notifies the calculation control unit 4 to that effect.

  Receiving the notification that it is in a steady state, the arithmetic control unit 4 requests the spectral sensitivity calculation unit 41 to calculate the spectral sensitivity.

  Upon receiving the request, the spectral sensitivity calculation unit 41 obtains the irradiance from the amplification unit 18 to calculate the irradiance dE per unit area, reads the irradiation area A of the solar cell PV from the storage unit 8, and from the detection unit 3. The current value dI is acquired, the spectral sensitivity S (I, λ) = dI (λ) × A / dE (λ) is calculated, and passed to the arithmetic control unit 4 (step S15).

  Receiving the spectral sensitivity from the spectral sensitivity calculation unit 41, the arithmetic control unit 4 stores the spectral sensitivity in the storage unit 8 in association with the irradiating monochromatic light (step S16).

  The arithmetic control unit 4 having the spectral sensitivity stored in the storage unit 8 determines whether or not the spectral sensitivity has been measured for all the monochromatic lights for all the wavelengths to be measured (step S17). If it is determined that measurement has not been performed for all monochromatic lights (step S17: No), the arithmetic control unit 4 performs the processing from step S11 to step S17 for all monochromatic lights.

  When it is determined that the spectral sensitivities have been measured for all the monochromatic lights for all the wavelengths to be measured (step S17: Yes), the arithmetic control unit 4 reads out and reads the spectral sensitivities of all the monochromatic lights from the storage unit 8. That the spectral sensitivity and the measurement of the spectral sensitivity are completed are displayed on the output unit 6 (step S18), and the process is terminated.

In the solar cell evaluation apparatus S as described above, it is possible to save time and effort for determining the waiting time until the output current of the solar cell PV reaches a steady state by trial and error, and it is optimal for each monochromatic light. Since the spectral sensitivity can be measured in a state, it is possible to perform a quick measurement while reducing a wasteful waiting time as much as possible in the measurement of the spectral sensitivity.
<Modification 1>
In the embodiment, the output current of the solar cell PV is monitored after starting the irradiation of each monochromatic light, and the absolute value of the slope of the tangent line (differential coefficient) in the curve representing the output current with respect to the elapsed time is smaller than a predetermined threshold value. At this time, the spectral sensitivity is calculated by determining that it is in a steady state.

  In Modification 1, when performing the spectral sensitivity measurement process in the embodiment, the time from the start of monochromatic light irradiation until it is determined to be in a steady state is measured and stored as the irradiation time for each monochromatic light. . And it uses for the spectral sensitivity measurement process of the solar cell PV of the same kind as the solar cell PV which measured time.

  In the spectral sensitivity measurement process of the solar cell PV of the same type, without determining whether or not the absolute value of the tangent slope (derivative coefficient) in the curve representing the output current with respect to the elapsed time is smaller than a predetermined threshold value, Since it is only necessary to measure the irradiation time, the spectral sensitivity can be measured more easily.

  The configuration of the solar cell evaluation device S of the present modification 1 is the same as the configuration shown in FIG. 3, but the arithmetic control unit 4 further includes a so-called timer, has a function of measuring elapsed time, and is monochromatic. The elapsed time from the start of light irradiation is measured.

  Moreover, the solar cell evaluation apparatus S of the modification 1 performs the following process in addition to the spectral sensitivity measurement process described using the flowchart of FIG.

  From the start of monochromatic light irradiation in step S12, the arithmetic control unit 4 starts measuring elapsed time. Receiving the notification that the steady state is received from the change detection unit 42 in step S14, the calculation control unit 4 uses the measured elapsed time as the irradiation time between the processing in step S14 and the processing in step S15. The data is stored in the storage unit 8 in association with the wavelength of the monochromatic light.

  By performing such processing, the solar cell evaluation apparatus S measures and memorizes the irradiation time until it reaches a steady state for each monochromatic light while measuring the spectral sensitivity of the solar cell PV.

  Next, using FIG. 5, the spectral sensitivity measurement processing of the solar cell PV of the same type as the solar cell PV whose irradiation time was measured (hereinafter referred to as “first solar cell PV”), that is, the irradiation time The spectral sensitivity measurement process used will be described.

  When the operator (user) places the solar cell PV to be evaluated at a predetermined position (step S20) and receives an instruction to start measurement of the solar cell PV using the irradiation time from the input unit 5, the arithmetic control unit 4 Instruct each functional unit to start operation. Thereafter, the calculation control unit 4 reads out the entire wavelength range to be measured, the pitch of the wavelength to be measured, and the irradiation time stored in association with each monochromatic light from the storage unit 8, and outputs the monochromatic light of the first wavelength. The evaluation light source drive control unit 11 and the monochromator 14 are controlled so that the evaluation light source unit 12 irradiates (step S21), and the start of monochromatic light irradiation is instructed (step S22). It is desirable that the order of monochromatic light to be irradiated is the same as that in the measurement of the first solar cell PV. Specifically, in the measurement process of the first solar cell PV, when the monochromatic light of the wavelength shifted by the pitch in the direction of the long wavelength from the shortest wavelength among all the wavelength ranges to be measured is sequentially irradiated, from the short wavelength The monochromatic light is irradiated in order by shifting the pitch. This is because the monochromatic light previously irradiated causes a hysteresis effect and the stabilization waiting time has wavelength dependency.

  The calculation control unit 4 that has instructed the start of monochromatic light irradiation reads the irradiation time stored in the storage unit 8 in association with the emitted monochromatic light, starts counting the time (step S23: No), and the irradiation time. (Step S23: Yes), the spectral sensitivity calculation unit 41 is requested to calculate the spectral sensitivity. For example, in FIG. 3, when the irradiation of the monochromatic light with the wavelength λ3 is started at time t20, the spectral sensitivity calculation unit 41 is requested to calculate the spectral sensitivity at time t21. Similarly, when the irradiation of the monochromatic light of wavelength λ4 is started at time t21, the spectral sensitivity calculation unit 41 is requested to calculate the spectral sensitivity at time t22.

  Upon receiving the request, the spectral sensitivity calculation unit 41 obtains the irradiance from the amplification unit 18 to calculate the irradiance dE per unit area, reads the irradiation area A of the solar cell PV from the storage unit 8, and from the detection unit 3. The current value dI is acquired (step S24), the spectral sensitivity S (I, λ) = dI (λ) × A / dE (λ) is calculated and passed to the arithmetic control unit 4 (step S25).

  Receiving the spectral sensitivity from the spectral sensitivity calculation unit 41, the calculation control unit 4 stores the spectral sensitivity of the solar cell PV currently being measured in the storage unit 8 in association with the irradiating monochromatic light (step S26).

  The arithmetic control unit 4 having the spectral sensitivity stored in the storage unit 8 determines whether or not the spectral sensitivity has been measured for all the monochromatic lights for all the wavelengths to be measured (step S27). If it is determined that measurement has not been performed for all monochromatic lights (step S27: No), the arithmetic control unit 4 performs the processing from step S21 to step S27 for all monochromatic lights.

  When it is determined that the spectral sensitivities have been measured for all the monochromatic lights for all wavelengths to be measured (step S27: Yes), the arithmetic control unit 4 reads out and reads the spectral sensitivities of all the monochromatic lights from the storage unit 8. The spectral sensitivity and the fact that the measurement of spectral sensitivity has been completed are displayed on the output unit 6 (step S28), and the process is terminated.

  By the above process, the spectral sensitivity of the same type of solar cell PV as the first solar cell PV can be obtained in a short time.

  In the solar cell evaluation apparatus S of Modification 1, the irradiation time of all monochromatic light for each pitch is measured, but the irradiation time is measured and stored for some monochromatic light, and the measured wavelength is measured. And the irradiation time of monochromatic light that is not measured may be calculated based on the irradiation time. For example, by measuring the irradiation time of monochromatic light having a wavelength at every other pitch, the irradiation time of monochromatic light having a skipped wavelength is interpolated from the irradiation time of monochromatic light having wavelengths before and after the monochromatic light (for example, It may be calculated by linear interpolation). When the pitch is equal, the irradiation time of monochromatic light of the front and rear wavelengths is added and divided by two. If the pitches are not equal, the weighted average is determined by the wavelength interval. Moreover, it is good also as calculating | requiring the relational expression of the measured wavelength and irradiation time, and calculating | requiring the irradiation time of the monochromatic light of the skipped wavelength from a relational expression. For example, the relational expression is obtained from the wavelength measured within the wavelength range including the skipped wavelength and the irradiation time. In addition, the wavelength range including the skipped wavelength includes only wavelengths shorter than the skipped wavelength, includes only wavelengths longer than the skipped wavelength, and includes wavelengths shorter and longer than the skipped wavelengths. The wavelength of the wavelength may be included.

  In the solar cell evaluation apparatus S, when the spectral sensitivity of the solar cell PV is measured using the irradiation time, the irradiation time of the same or similar solar cell PV is used, or the irradiation time of the same or similar solar cell PV. The time estimated from the above may be used.

<Modification 2>
In Modification 1, the irradiation time was measured for all monochromatic light for each pitch in the entire wavelength range to be measured, and the spectral sensitivity of the solar cell PV was measured by changing the irradiation time for each monochromatic light.

  In Modification 2, a case will be described in which all wavelengths are divided into a plurality of blocks so as to include a plurality of monochromatic lights to be measured, and one irradiation time is used for each block. Blocking is performed by making monochromatic light into a single block whose waiting time after the start of monochromatic light irradiation falls within a predetermined time range. For example, when the predetermined time range is 3 to 6 seconds, the wavelength of the monochromatic light whose waiting time after starting the monochromatic light irradiation is longer than 3 seconds and shorter than 6 seconds belongs to one block. Become.

  FIG. 6 is a flowchart of processing for obtaining the irradiation time of the solar cell PV and measuring the spectral sensitivity. The solar cell PV of the same type as this solar cell PV (the first solar cell PV) calculates the spectral sensitivity by performing irradiation for each monochromatic light in the same manner as the processing described with reference to FIG. . However, the difference from FIG. 5 is that the irradiation time differs for each block, not for each monochromatic light.

  Hereinafter, the spectral sensitivity measurement process will be described with reference to the flowchart of FIG.

  When the operator (user) places the solar cell PV to be evaluated at a predetermined position (step S30) and receives an instruction to start measurement of the first solar cell PV from the input unit 5, the arithmetic control unit 4 To start operation. Thereafter, the calculation control unit 4 reads out the entire wavelength range to be measured and the pitch of the wavelength to be measured from the storage unit 8, and divides the entire wavelength range into a plurality of blocks (step S31). In the embodiment, it is assumed that the monochromatic light belonging to the block has a continuous wavelength. The user may perform block division via the input unit 5 and the output unit 6.

  The calculation control unit 4 divided into blocks controls the evaluation light source drive control unit 11 and the monochromator 14 so that the evaluation light source unit 12 emits representative single color light among a plurality of single color lights constituting the first block. Then, the start of monochromatic light irradiation is instructed (step S32). In the embodiment, the representative monochromatic light is the monochromatic light having the longest wavelength among the monochromatic lights constituting the block. This is because, in general, it takes longer for the output current of the solar cell PV to reach a steady state when the long wavelength monochromatic light is irradiated than when the short wavelength monochromatic light is irradiated.

  The calculation control unit 4 that has instructed the start of monochromatic light irradiation requests the change detection unit 42 to monitor the change in the output of the detection unit 3 and starts counting elapsed time.

  Upon receiving the request, the change detection unit 42 acquires the output current of the solar cell PV detected by the detection unit 3 at a predetermined sampling interval, and whether or not the acquired output current is in a steady state, that is, the tangential slope. It is determined whether or not the absolute value is smaller than a threshold value (step S34).

  If the absolute value of the slope is equal to or greater than the threshold value (step S34: No), the change detection unit 42 determines that it is still in a transient state, and further obtains the output current from the detection unit 3 and makes a determination. When the absolute value of the slope is smaller than the threshold value (step S34: Yes), the change detecting unit 42 determines that the steady state is present, and notifies the calculation control unit 4 to that effect.

  Receiving the notification that the steady state is received from the change detection unit 42, the calculation control unit 4 uses the elapsed time counted as the irradiation time and associates it with the block to which the currently emitted monochromatic light belongs in the storage unit 8. Store (step S35).

  The calculation control unit 4 having the irradiation time stored in the storage unit 8 requests the spectral sensitivity calculation unit 41 to calculate the spectral sensitivity.

  Upon receiving the request, the spectral sensitivity calculation unit 41 obtains the irradiance from the amplification unit 18 to calculate the irradiance dE per unit area, reads the irradiation area A of the solar cell PV from the storage unit 8, and from the detection unit 3. The current value dI is acquired, and the spectral sensitivity S (I, λ) = dI (λ) × A / dE (λ) is calculated and passed to the arithmetic control unit 4 (step S36).

  The calculation control unit 4 that has received the spectral sensitivity from the spectral sensitivity calculation unit 41 stores it in the storage unit 8 in association with the irradiating monochromatic light (step S37).

  Next, the arithmetic control unit 4 controls the evaluation light source drive control unit 11 and the monochromator 14 so that the evaluation light source unit 12 irradiates the monochromatic light that has not yet been measured in the block (step S38), and the monochromatic light. Is started (step S39).

  The calculation control unit 4 that has instructed the start of monochromatic light irradiation associates with the block to which the monochromatic light being illuminated belongs and is stored in the storage unit 8, that is, the irradiation stored in the storage unit 8 in step S35. Time counting is started (step S40: No), and when the irradiation time has elapsed (step S40: Yes), the spectral sensitivity calculation unit 41 is requested to calculate the spectral sensitivity.

  Upon receiving the request, the spectral sensitivity calculation unit 41 obtains the irradiance from the amplification unit 18 to calculate the irradiance dE per unit area, reads the irradiation area A of the solar cell PV from the storage unit 8, and from the detection unit 3. The current value dI is acquired (step S41), the spectral sensitivity S (I, λ) = dI (λ) × A / dE (λ) is calculated and passed to the arithmetic control unit 4 (step S42).

  Receiving the spectral sensitivity from the spectral sensitivity calculation unit 41, the arithmetic control unit 4 stores the spectral sensitivity of the solar cell PV currently being measured in the storage unit 8 in association with the irradiating monochromatic light (step S43).

  The arithmetic control unit 4 having the spectral sensitivity stored in the storage unit 8 determines whether or not the spectral sensitivity has been measured for the monochromatic light belonging to the block (step S44). If it is determined that measurement has not been performed for all monochromatic lights (step S44: No), the arithmetic control unit 4 performs the processing from step S38 to step S44 for all monochromatic lights belonging to the block.

  When it is determined that the spectral sensitivity has been measured for all the monochromatic lights in the block (step S44: Yes), the arithmetic control unit 4 measures the spectral sensitivity for all the wavelengths to be measured, that is, for the monochromatic light of all the blocks. It is determined whether or not the process is over (step S45). If it is determined that measurement has not been performed for all blocks (step S45: No), the arithmetic control unit 4 performs the processing from step S32 to step S45 for all blocks.

  When it is determined that the spectral sensitivities have been measured for all the monochromatic lights for all the blocks (step S45: Yes), the arithmetic control unit 4 reads the spectral sensitivities of all the monochromatic lights from the storage unit 8, and reads the spectral sensitivities. The fact that the measurement of the spectral sensitivity is completed is displayed on the output unit 6 (step S46), and the process is terminated.

  In the solar cell evaluation apparatus S of the modified example 2, since the monochromatic light with a short wavelength has little difference in the irradiation time until the steady state is reached, it is efficient by collectively blocking a plurality of monochromatic lights. It becomes possible to measure spectral sensitivity.

  In Modification 1, the irradiation time is determined for each monochromatic light, and in Modification 2, the irradiation time is determined for each block. Using the longest irradiation time among all the monochromatic lights, measurement of all monochromatic light is performed. Also good. Although the irradiation time of each monochromatic light is not the shortest, the time required for determining the irradiation time by trial and error becomes unnecessary.

  In order to express the present invention, the present invention has been properly and fully described through the embodiments with reference to the drawings. However, those skilled in the art can easily change and / or improve the above-described embodiments. It should be recognized that this is possible. Therefore, unless the modifications or improvements implemented by those skilled in the art are at a level that departs from the scope of the claims recited in the claims, the modifications or improvements are not covered by the claims. To be construed as inclusive.

S solar cell evaluation apparatus PV solar cell 1 evaluation light irradiation unit 3 detection unit 4 calculation control unit 8 storage unit 12 evaluation light source unit 17 irradiance detection unit 41 spectral sensitivity calculation unit 42 change detection unit

Claims (5)

An evaluation light irradiator that sequentially irradiates a plurality of monochromatic lights of different wavelengths to a solar cell to be evaluated that needs to be irradiated with monochromatic light for a predetermined time before the evaluation,
A detection unit for detecting an output of the solar cell when the plurality of monochromatic lights are sequentially irradiated ;
Monitoring the output detected by the detection unit from the start of each of the irradiation of the that by the evaluation light irradiation portion of the plurality of monochromatic light, the output variation of the solar cell at a given time divided by the predetermined time tilt Kiga, a storage unit for each of the time stored in advance in association with the plurality of monochromatic light each having a wavelength up to when it becomes within the predetermined range,
With respect to each of the plurality of monochromatic lights sequentially irradiated from the evaluation light irradiation unit, the passage of the time stored in advance in the storage unit in association with the wavelength of the monochromatic light from the start of the monochromatic light irradiation A solar cell evaluation apparatus comprising: a spectral sensitivity calculation unit that calculates the spectral sensitivity of each of the plurality of monochromatic lights using an output that is detected later by the detection unit . The storage unit does not previously store the time for monochromatic light having a wavelength different from that of the plurality of monochromatic lights,
The evaluation light irradiation unit can irradiate the monochromatic light of the different wavelengths,
The spectral sensitivity calculating unit, when the monochromatic light before Kikoto consisting wavelength is irradiated by the evaluation light irradiation unit, of wavelengths of the monochromatic light stored in the storage unit, is irradiated based on the time associated with the wavelength and the wavelength associated with the wavelength of the monochromatic light, calculates a time corresponding to the wavelength of the monochromatic light to be irradiated, the irradiation of the monochromatic light by the evaluation light irradiation unit starting from the solar cell evaluation device according to claim 1, characterized in that calculating the spectral sensitivity using a detected by the detecting unit after the lapse of the calculated time output. The spectral sensitivity calculation unit is associated with a wavelength before and after the wavelength of the monochromatic light irradiated by the evaluation light irradiation unit among the wavelengths of the plurality of monochromatic lights stored in the storage unit and the wavelength. The solar cell evaluation device according to claim 2 , wherein the time corresponding to the wavelength of the monochromatic light to be irradiated is calculated by interpolation based on the time that is present. The spectral sensitivity calculation unit corresponds to a wavelength belonging to a wavelength range including the wavelength of the monochromatic light irradiated by the evaluation light irradiation unit among the wavelengths of the plurality of monochromatic lights stored in the storage unit, and the wavelength based on the time that given obtains the relational expression between the wavelength and time, by the equation, according to claim 2, characterized in that to calculate the time corresponding to the wavelength of the monochromatic light irradiated Solar cell evaluation device. An evaluation light irradiation step of sequentially irradiating a plurality of single-color lights of different wavelengths to a solar cell to be evaluated that needs to be irradiated with monochromatic light for a predetermined time before the evaluation,
A detection step of detecting an output of the solar cell when the plurality of monochromatic lights are sequentially irradiated ;
Monitoring the output detected by said detecting step from the start of each of the irradiation of the that by the evaluation light irradiation step wherein the plurality of monochromatic light, the output variation of the solar cell at a given time divided by the predetermined time tilt Kiga, a storage step for each time, stored in advance in association with the wavelength of each of the plurality of monochromatic light up when it becomes within the predetermined range,
With respect to each of the plurality of monochromatic lights sequentially irradiated in the evaluation light irradiation step, the passage of time stored in advance in the storage step in association with the wavelength of the monochromatic light from the start of the monochromatic light irradiation A solar cell evaluation method comprising: a spectral sensitivity calculation step of calculating a spectral sensitivity of each of the plurality of monochromatic lights using an output detected in the detection step later .

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