Current-voltage measurement and mathematical modeling of perovskite solar modules

Abstract

The present invention relates to a method for measuring the current-voltage (IV) characteristics of a perovskite solar module and mathematically modeling the same, which enables accurate and rapid measurement of the current-voltage (IV) characteristics of the perovskite solar module without constant temperature control and without errors caused by artifacts. The method comprises the steps of: measuring the current-voltage curve by scanning the current-voltage in the forward and reverse directions within 100ms while irradiating the perovskite solar module with a light source; defining the section where the current-voltage curve matches and the section where hysteresis occurs; measuring the current value by turning the light source ON or OFF in each region through voltage scanning for 30 to 70ms in the section where hysteresis occurs, and obtaining basic point data of the current-voltage curve within a maximum of 200ms; averaging the current values ​​measured in the section where hysteresis occurs to generate a graph of current versus voltage; calculating the current-voltage curve as a mathematical model through the generated graph; and writing a result report through the calculated current-voltage curve.

Description

Technology Field

[0001] The present invention relates to a current-voltage measuring device for a perovskite photovoltaic module, and in particular to a method for measuring the current-voltage (IV) of a perovskite photovoltaic module and mathematically modeling the same, which enables accurate and rapid measurement of the current-voltage (IV) characteristics of the perovskite photovoltaic module without constant temperature control and without errors caused by artifacts. Background Technology

[0002] Recently, due to environmental issues such as regulations on carbon dioxide emissions and global warming, interest in renewable energy to replace conventional fossil fuels is increasing. Among these, solar energy is attracting attention as an infinite and clean energy resource. A solar cell is a device that converts solar energy into electrical energy.

[0003] Generally, solar cells are manufactured to be opaque to increase the efficiency of converting solar energy into electrical energy. However, due to this opaque characteristic, the use of such solar cells has been limited.

[0004] To solve this problem, the recent development of thin-film solar cells, such as dye-sensitized solar cells, organic solar cells, and perovskite solar cells, has made it possible to fabricate solar cells that are semi-transparent.

[0005] Active research is underway to apply these translucent solar cells to glass windows for use in buildings, automobiles, and the like. However, due to the inherent low light transmittance of translucent solar cells, the amount of light absorbed is relatively small, resulting in a disadvantage of lower light conversion efficiency compared to conventional silicon solar cells.

[0006] Recently, organometallic halogen perovskite solar cells have been showing results comparable to the efficiency of conventional silicon solar cells. These perovskite solar cells have a photoactive layer thickness of several hundred nanometers, and possess high photoelectric conversion efficiency while allowing light to pass through.

[0007] In other words, perovskite solar cells have the advantage of possessing excellent light absorption capabilities and high efficiency potential, while also being able to be manufactured on a large scale at low cost based on low-temperature solution processes. In particular, perovskite compounds allow for the free design of band gaps through composition and structure control, and this enables various applications such as single junctions, tandem structures with silicon, transparent solar cells, and building-integrated photovoltaics (BIPV).

[0008] Thanks to these characteristics and material diversity, perovskite solar cells complement the limitations of conventional silicon solar cells and are a material that must be developed as a high-efficiency, low-cost next-generation solar power generation technology required for the carbon-neutral era.

[0009] However, despite their high potential, perovskite solar cells have various artifacts and errors during the current-voltage (IV) curve measurement process due to their inherent capacitance characteristics. This leads to problems such as distorted evaluation of the device's actual performance or overestimation or underestimation of efficiency values, making reliable measurement difficult.

[0010] To overcome artifact phenomena in relatively small solar cells, a measurement method is used in which the scan time of the IV curve is slowed down while a light source is continuously irradiated within a narrow, temperature-controlled space.

[0011] However, solar modules, which are larger than solar cells, face limitations in accurate IV curve measurements because they cannot irradiate the module with a light source for extended periods while controlling the ambient temperature due to the size and cost of the device required to control the module temperature. The problem to be solved

[0012] The present invention aims to solve the above-mentioned problem by providing a method for measuring the current-voltage (IV) characteristics of a perovskite photovoltaic module and mathematically modeling the same, which enables accurate and rapid measurement of the IV characteristics of the perovskite photovoltaic module without constant temperature control and without errors caused by artifacts. means of solving the problem

[0013] The current-voltage measurement and mathematical modeling method of a perovskite solar module according to the present invention for achieving the above-mentioned purpose comprises: a step of measuring a current-voltage curve by scanning the current-voltage in the forward and reverse directions within 100ms while irradiating a light source onto a perovskite solar module; a step of defining a section where the current-voltage curve matches and a section where hysteresis occurs; a step of measuring current values ​​by turning the light source ON or OFF in each region through voltage scanning for 30 to 70ms in the section where hysteresis occurs, and acquiring basic point data of the current-voltage curve within a maximum of 200ms; a step of generating a graph of current versus voltage by averaging the current values ​​measured in the section where hysteresis occurs; a step of calculating the current-voltage curve as a mathematical model through the generated graph; and a step of writing a result report through the calculated current-voltage curve. Effects of the invention

[0014] The current-voltage measurement and mathematical modeling method of a perovskite photovoltaic module according to an embodiment of the present invention has the following effects.

[0015] In other words, the current-voltage (IV) characteristics of a perovskite photovoltaic module can be measured accurately and quickly without constant temperature control and without errors caused by artifacts. Brief explanation of the drawing

[0016] Figure 1 is a graph showing the hysteresis phenomenon of the current-voltage (IV) curve of a typical perovskite solar cell. FIG. 2 is a flowchart for explaining the current-voltage measurement and mathematical modeling method of a perovskite photovoltaic module according to the present invention. Figure 3 is a graph for explaining how to set the voltage scan region for the hysteresis section of the current-voltage (IV) curve of a solar cell. FIG. 4 is a diagram illustrating a method for setting the light source ON-OFF time during a voltage scan in the present invention. 5 is a graph showing the current value averaged from the measured voltage scan as current versus voltage. Figure 6 is a graph showing the degree of curvature of the curve according to each mathematical equation in the current-voltage (IV) curve. FIG. 7 is a graph showing the current-voltage (IV) curve retrieved using values ​​obtained from Equations 1 to 5 in the present invention. Specific details for implementing the invention

[0017] Hereinafter, with reference to the attached drawings, a method for measuring current-voltage of a perovskite photovoltaic module and mathematically modeling the same according to an embodiment of the present invention will be described in detail. Prior to this, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, and based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention, they should be interpreted in a meaning and concept consistent with the technical spirit of the present invention.

[0018] Additionally, identical or corresponding components are assigned the same reference number regardless of the drawing symbol, and redundant descriptions thereof are omitted; furthermore, for the convenience of explanation, the size and shape of each illustrated component may be exaggerated or reduced.

[0019] Figure 1 is a graph showing the hysteresis phenomenon of the current-voltage (IV) curve of a typical perovskite solar cell.

[0020] Generally, hysteresis in the IV curve of perovskite solar cells occurs due to the complex interplay of internal ion movement, accumulation and emission delays caused by interfacial charge traps, capacitance effects, and dielectric polarization phenomena.

[0021] Due to this internal degradation delay phenomenon, the current response varies depending on the voltage scan direction and speed, causing a problem where the evaluation of the device's actual performance is distorted.

[0022] When the current-voltage (IV) curve of an actual solar cell is measured in the forward direction (Voc → Isc) and the reverse direction (Isc → Voc), the current (I) curve and the voltage (V) curve do not coincide and show a difference, as shown in Fig. 1. A measurement method is used to complete the measurement of the current-voltage (IV) curve within a few milliseconds by applying the average value of the current curve and the voltage curve to obtain an average curve.

[0023] This rarely appears in general silicon solar cells, but is observed very distinctly in perovskite solar cells. In the case of photovoltaic modules with high capacitance, when measuring the IV curve, the measurement time is set to 30 seconds or more under continuous accumulation of light sources to measure the IV curve.

[0024] The current-voltage measurement and mathematical modeling method of a perovskite photovoltaic module according to the present invention is as follows.

[0025] FIG. 2 is a flowchart for explaining the current-voltage measurement and mathematical modeling method of a perovskite photovoltaic module according to the present invention, and FIG. 3 is a graph for explaining the method of setting a voltage scan area for the hysteresis section of the current-voltage (IV) curve of a solar cell.

[0026] In addition, FIG. 4 is a diagram illustrating a method for setting the ON-OFF time of a light source during a voltage scan in the present invention, and FIG. 5 is a graph showing the current value according to the measured voltage scan as an average of the current values ​​and the current versus voltage.

[0027] In addition, FIG. 6 is a graph showing the degree of curvature of the curve according to each mathematical formula in the current-voltage (IV) curve, and FIG. 7 is a graph showing the current-voltage (IV) curve searched using values ​​obtained from mathematical formulas 1 to 5 in the present invention.

[0028] The method for measuring current-voltage of a perovskite photovoltaic module and mathematically modeling the same according to the present invention performs a current-voltage (IV) scan in the forward and reverse directions within 100 ms to obtain a current-voltage (IV) curve while preventing the temperature of the photovoltaic module from rising due to irradiation of a light source on the photovoltaic module as shown in FIG. 2. Then, the section where the two curves coincide and the section where hysteresis occurs are divided and distinguished.

[0029] Then, for the hysteresis section, the voltage range to be scanned over time in Zone 2 is set as shown in Fig. 3. Here, about 5 to 6 voltage scan ranges are set for the Pmax section. If more than 6 voltage scan ranges are set, the accumulated time of light source irradiation increases, causing the module temperature to rise. Additionally, a voltage range where hysteresis begins is additionally set and scanned.

[0030] Next, the current value is measured while performing a voltage scan within 30 to 70 ms for a set voltage in Zone 2.

[0031] As shown in Fig. 4, when a voltage scan of one section is finished, the light source is turned OFF, and the waiting time until the next voltage scan is one hour after the previous voltage scan, and then the next voltage scan is performed.

[0032] If you proceed with this measurement method, you will obtain basic point data of the IV curve within a maximum of 200 ms.

[0033] Next, the current values ​​according to the above-mentioned measured voltage scan are averaged to plot a graph of current versus voltage.

[0034] Next, a mathematical formula is used to describe the current-voltage (IV) curve using only the information obtained from Fig. 5. This mathematical formula can represent the current-voltage curve obtained under different conditions, such as when the photovoltaic module has a diode characteristic curve, as Equation 1 below.

[0035]

[0036] Here, Iph, Id, Rs, Rsh, and Vt represent the photocurrent, dark current, series resistance, shunt resistance, and thermionic voltage, respectively.

[0037] And to solve the above mathematical formula 1, the following mathematical formulas 2 through 5 are required.

[0038] First, the expression for the short-circuit current (Isc) can be represented by the following mathematical equation 2.

[0039]

[0040] In addition, the equation expressing the open-circuit voltage (O) can be represented by the following mathematical equation 3.

[0041]

[0042] In addition, the expression for the maximum current (Imax) can be represented by the following mathematical equation 4.

[0043]

[0044] The equation for calculating the diode ideality factor (n) can be expressed by the following mathematical equation 5.

[0045]

[0046] Meanwhile, in the mathematical formula for representing the current-voltage (IV) curve, the diode ideality factor is a measure of the degree of bending of the curve (Fig. 6).

[0047] The current-voltage (IV) curve obtained using the values ​​from mathematical formulas 1 to 5 is shown as in Fig. 7.

[0048] Here, the diode ideality factor, n, is determined by varying values ​​between 1 ≤ n ≤ 2, selecting the value that minimizes the Root Mean Square (RMS) deviation. This can be expressed by Equation 6 as follows.

[0049]

[0050] Finally, the current-voltage (IV) measurement results are produced in the form of a report.

[0052] Meanwhile, although the present invention has been described above with specific details such as specific components, limited embodiments, and drawings, this is provided merely to aid in a more comprehensive understanding of the invention, and the invention is not limited to the above embodiments. A person skilled in the art to which the invention pertains can make various modifications and variations from this description.

[0053] Accordingly, the scope of the present invention should not be limited to the described embodiments, and all things equivalent to or having equivalent variations to the claims set forth below, as well as the claims set forth below, shall be considered to fall within the scope of the concept of the present invention.

Claims

Claim 1 A step of measuring a current-voltage curve by scanning the current-voltage in the forward and reverse directions within 100ms while illuminating a perovskite solar module with a light source; a step of defining the section where the current curve and the voltage curve coincide and the section where hysteresis occurs; a step of measuring current values ​​by turning the light source ON or OFF by region through voltage scanning for 30 to 70ms in the section where hysteresis occurs, and acquiring basic point data of the current-voltage curve within a maximum of 200ms; a step of generating a graph of current versus voltage by averaging the current values ​​measured in the section where hysteresis occurs; a step of calculating the current-voltage curve using a mathematical model through the generated graph; and a step of preparing a result report using the calculated current-voltage curve; wherein the mathematical model includes current (I) (Equation 1), short-circuit current (Isc) (Equation 2), open-circuit voltage (O) (Equation 3), maximum current (Imax) (Equation 4), and diode ideality factor (Idiode) (Equation A method for measuring current-voltage of a perovskite photovoltaic module and mathematically modeling the same, characterized by calculating 5) to search for a current-voltage curve and calculating the root mean square deviation (RMS) value (Equation 6) while inputting values ​​between 1 ≤ n ≤ 2 for the diode ideality factor n. [Equation 1] (Here, Iph is photocurrent, Id is dark current, Rs is series resistance, Rsh is shunt resistance, Vt is thermionic voltage)[Equation 2] [Mathematical Formula 3] [Mathematical Formula 4] [Mathematical Formula 5] , [Mathematical Formula 6] Claim 2 A method for measuring current-voltage of a perovskite photovoltaic module and mathematically modeling the same, wherein, in claim 1, the hysteresis section is characterized by setting and proceeding with a plurality of voltage regions that scan over time. Claim 3 A method for measuring current-voltage of a perovskite photovoltaic module and mathematically modeling the same, wherein, in claim 2, when the input scan of one region is completed, the light source is turned OFF and the waiting time until another voltage scan is performed is the time taken for the previous voltage scan, and then the next input scan is performed.

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