Hydrogen production equipment degradation detection system

Abstract

To provide a hydrogen production equipment degradation detection system that can easily detect the deterioration of hydrogen production equipment. [Solution] The power supply unit starts by supplying a current of a first current value to the electrolytic unit, then at a first time point, it supplies a current of a second current value different from the first current value to the electrolytic unit, and then at a second time point, it returns to a state where it supplies a current of the first current value to the electrolytic unit. The degradation detection unit calculates the difference between a first electrolytic unit voltage measurement value obtained as an electrolytic unit voltage measurement value when the current of the first current value is supplied to the electrolytic unit before the first time point, and a second electrolytic unit voltage measurement value obtained as an electrolytic unit voltage measurement value when the current of the first current value is switched to the current of the second current value at the first time point, and detects degradation of the electrolytic unit according to the electrolytic unit voltage difference value.

Description

Technical Field

[0001] Embodiments of the present invention relate to a hydrogen production apparatus deterioration detection system.

Background Art

[0002] In recent years, hydrogen production apparatuses have been attracting attention in order to realize a hydrogen energy society. A hydrogen production apparatus is configured to generate hydrogen gas, for example, by electrolyzing high-temperature steam in an electrolysis unit. The electrolysis unit includes, for example, an electrolysis cell stack in which a plurality of electrolysis cells are stacked in order to meet the demand for an increase in hydrogen production amount.

[0003] In order to improve the performance of the hydrogen production apparatus as described above, various techniques have been proposed. For example, it has been proposed to generate steam using power that varies such as power generated by renewable energy, and perform pulse width control on the power supplied to the electrolysis cell stack according to the flow rate of the steam. In addition, it has been proposed to select the number of electrolysis cells to be driven according to the varying power.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] Hydrogen production equipment may deteriorate during long-term operation. For example, catalytic components (such as nickel) that make up the hydrogen electrode in the electrolytic cell may disappear, or chromium poisoning may occur in the electrolytic cell. In addition, deterioration may occur in the current supply line that supplies current from the power supply unit to the electrolytic unit (for example, increased contact resistance due to loosening of fasteners). As a result, it may become difficult to produce hydrogen stably and efficiently.

[0006] Due to the circumstances described above, there is a need for a simple way to detect the deterioration of hydrogen production equipment. In particular, there is a need to detect deterioration while the hydrogen production equipment is operating continuously.

[0007] Therefore, the problem that the present invention aims to solve is to provide a hydrogen production equipment deterioration detection system that can easily detect the deterioration of a hydrogen production equipment. [Means for solving the problem]

[0008] The hydrogen production apparatus degradation detection system of this embodiment includes a degradation detection unit and detects the degradation of a hydrogen production apparatus configured to perform electrolysis of water by supplying current to an electrolytic unit from a power supply unit via a current supply line. The degradation detection unit is configured to detect the degradation of the electrolytic unit based on an electrolytic unit voltage measurement value obtained by measuring the voltage of the electrolytic unit when current is supplied to the electrolytic unit from the power supply unit. Here, the power supply unit performs power supply such that it starts from a state in which a current of a first current value is supplied to the electrolytic unit, then supplies a current of a second current value different from the first current value to the electrolytic unit at a first time point, and then returns to a state in which a current of the first current value is supplied to the electrolytic unit at a second time point. The degradation detection unit calculates the difference between a first electrolytic unit voltage measurement value obtained as an electrolytic unit voltage measurement value when a current of the first current value is supplied to the electrolytic unit before the first time point, and a second electrolytic unit voltage measurement value obtained as an electrolytic unit voltage measurement value when the current switches from the first current value to the second current value at the first time point, and detects the degradation of the electrolytic unit according to the electrolytic unit voltage difference value. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic diagram showing the configuration of the hydrogen production apparatus 1 according to the first embodiment. [Figure 2] Figure 2 is a schematic diagram showing the configuration of the hydrogen production apparatus degradation detection system 100 according to the first embodiment. [Figure 3A] Figure 3A is a diagram showing the current measurement value DI, the electrolytic unit voltage measurement value DV, and the electrolytic unit temperature measurement value DT that are input to the degradation detection unit 120 in the hydrogen production apparatus degradation detection system 100 according to the first embodiment. [Figure 3B] Figure 3B shows the voltage difference value ΔV and the temperature change rate HT (=ΔT / t) of the electrolytic unit, which are determined by the degradation detection unit 120 in the hydrogen production apparatus degradation detection system 100 according to the first embodiment. [Figure 4] Figure 4 shows the current measurement value DI, electrolytic unit voltage measurement value DV, and electrolytic unit temperature measurement value DT input to the degradation detection unit 120 in the comparative example. [Figure 5] Figure 5 shows the current measurement value DI, electrolytic unit voltage measurement value DV, and electrolytic unit temperature measurement value DT input to the degradation detection unit 120 in modified example 1-1. [Figure 6] Figure 6 is a diagram illustrating modified example 1-2. [Figure 7] Figure 7 is a schematic diagram showing the configuration of the hydrogen production apparatus degradation detection system 100 according to the second embodiment. [Figure 8A] Figure 8A is a diagram showing the current measurement value DI, the electrolytic unit voltage measurement value DV, and the power supply unit voltage measurement value VM input to the degradation detection unit 120 in the hydrogen production apparatus degradation detection system 100 according to the second embodiment. [Figure 8B] Figure 8B shows the power supply voltage difference value ΔVM obtained by the degradation detection unit 120 in the hydrogen production apparatus degradation detection system 100 according to the second embodiment. [Modes for carrying out the invention]

[0010] <First Embodiment> [A] Configuration of Hydrogen Production Device 1 Before explaining the hydrogen production device deterioration detection system of the first embodiment, an example of the hydrogen production device 1 that the hydrogen production device deterioration detection system detects deterioration will be described.

[0011] FIG. 1 is a diagram schematically showing the configuration of the hydrogen production device 1 according to the first embodiment.

[0012] As shown in FIG. 1, the hydrogen production device 1 has a power supply unit 10 and an electrolysis unit 20, and is configured to produce hydrogen by supplying current from the power supply unit 10 to the electrolysis unit 20 via the current supply line L11. Each part constituting the hydrogen production device 1 will be described sequentially.

[0013] [A-1] Power Supply Unit 10 The power supply unit 10 is provided to supply power to the electrolysis unit 20. The power supply unit 10 includes, for example, power generation equipment, and is configured such that the power generated by the power generation equipment is supplied to the electrolysis unit 20. In the power supply unit 10, the power generation equipment is configured to generate power using, for example, renewable energy (such as sunlight and wind power). In addition to this, the power generation equipment may be configured to generate power using fossil fuels or the like instead of renewable energy. Further, the power supply unit 10 may include a storage battery that stores the power output from the storage battery, and is configured to supply power from the storage battery to the electrolysis unit 20.

[0014] [A-2] Electrolysis Unit 20 The electrolysis unit 20 is electrically connected to the power supply unit 10 via the current supply line L11, and power is supplied from the power supply unit 10. The electrolysis unit 20 is configured to generate hydrogen by flowing a current due to the power supplied from the power supply unit 10 and performing electrolysis of water.

[0015] Here, the electrolysis unit 20 includes an electrolytic cell stack in which a plurality of electrolytic cells 21 are stacked and electrically connected in series. The electrolytic cell 21 is, for example, a solid oxide type electrolytic cell, and is configured such that a solid oxide electrolyte membrane (not shown) is interposed between a hydrogen electrode (not shown) and an oxygen electrode (not shown).

[0016] Here, the electrolysis unit 20 is housed in an electrolytic cell stack container 22. The electrolytic cell stack container 22 is configured such that its interior is maintained at a temperature of about 500 to 800°C by heating with, for example, an electric heater (not shown).

[0017] Steam is supplied to the hydrogen electrode of the electrolytic cell 21 as a raw material for hydrogen generation. The steam is supplied to the hydrogen electrode in a state mixed with hydrogen. Further, a dilution gas is supplied to the oxygen electrode of the electrolytic cell 21. Then, power is supplied to the electrolysis unit 20 from the power supply unit 10. Thereby, electrolysis is performed in the electrolytic cell 21, hydrogen is generated at the hydrogen electrode, and oxygen is generated at the oxygen electrode.

[0018] Specifically, water supplied from the water supply source 40 to the steam generation unit 50 via piping L40 is heated in the steam generation unit 50 to generate steam. The steam generated in the steam generation unit 50 is then mixed with hydrogen from the hydrogen supply source 41 via piping L41, and then flows into the hydrogen electrode of the electrolytic cell 21 constituting the electrolytic unit 20 via piping L50 (raw material supply line) where the heat exchanger 60 is installed. The hydrogen generated at the hydrogen electrode by the electrolysis of the steam then flows to the heat exchanger 60 via piping L21a (product discharge line) as a mixed medium mixed with the steam that was not electrolyzed. In the heat exchanger 60, the mixed medium that flowed in from piping L21a exchanges heat with the steam flowing through piping L50, and then flows into the separation unit 70 via piping L60. In the separation unit 70, the mixed medium is separated into hydrogen and steam. The hydrogen separated in the separation unit 70 is discharged to the outside of the separation unit 70 via piping L70a and stored, for example. In contrast, the steam separated in the separation unit 70 flows into piping L40 and mixes with the water flowing through piping L40 from the water supply source 40.

[0019] In this embodiment, hydrogen gas is contained in the water vapor that flows into the hydrogen electrode of the electrolytic unit 20 as a raw material to prevent oxidation of the hydrogen electrode. For example, it is preferable that the molar concentration of hydrogen gas in the raw material is 0.5 mol% or more. In particular, it is preferable that the molar concentration of hydrogen gas is 5 mol% or more and 50 mol% or less, and more preferably 10 mol% or more and 30 mol% or less.

[0020] The diluent gas supplied to the oxygen electrode of the electrolytic cell 21 is an oxygen-containing gas, such as air. The diluent gas is supplied from the diluent gas source 80 to the oxygen electrode of the electrolytic cell 21 via piping L80 (diluent gas supply line). The diluent gas is supplied to dilute the oxygen produced at the oxygen electrode by electrolysis. The mixed gas of the diluent gas and the oxygen produced at the oxygen electrode is discharged to the outside of the electrolytic cell 21 via piping L21b (produced oxygen discharge line).

[0021] [B] Configuration of the hydrogen production equipment degradation detection system Figure 2 is a schematic diagram showing the configuration of the hydrogen production apparatus degradation detection system 100 according to the first embodiment. Figure 2 shows the relationship between the hydrogen production apparatus degradation detection system 100 and a part of the hydrogen production apparatus 1 (see Figure 1).

[0022] As shown in Figure 2, the hydrogen production apparatus deterioration detection system 100 of this embodiment has a deterioration detection unit 120 and a notification unit 140, and detects deterioration of the hydrogen production apparatus 1. Although not shown, the hydrogen production apparatus deterioration detection system 100 includes, for example, a calculator (not shown) and a memory device (not shown), and is configured so that each part functions by the calculator performing calculations using a program stored in the memory device. Each part constituting the hydrogen production apparatus deterioration detection system 100 will be described in order.

[0023] [B-1] Deterioration detection unit 120 The degradation detection unit 120 receives the current measurement value DI, the electrolytic unit voltage measurement value DV, and the electrolytic unit temperature measurement value DT as input data.

[0024] The current measurement value DI is measurement data obtained by an ammeter 11 measuring the current supplied from the power supply unit 10 to the electrolysis unit 20 in the hydrogen production apparatus 1.

[0025] The electrolytic unit voltage measurement value DV is measurement data obtained when a voltmeter 12 measures the voltage of the electrolytic unit 20 when current is supplied from the power supply unit 10 to the electrolytic unit 20 in the hydrogen production apparatus 1.

[0026] The electrolytic unit temperature measurement value DT is measurement data obtained when a thermometer 13 measures the temperature of the electrolytic unit 20 when current is supplied from the power supply unit 10 to the electrolytic unit 20 in the hydrogen production apparatus 1.

[0027] As will be described in more detail later, the degradation detection unit 120 detects the degradation of the electrolytic unit 20 based on the current measurement value DI, the electrolytic unit voltage measurement value DV, and the electrolytic unit temperature measurement value DT.

[0028] [B-1] Hochi Department 140 The notification unit 140 is configured to notify the user of the need to replace the electrolytic unit 20 based on the deterioration detected by the deterioration detection unit 120. For example, when the notification unit 140 determines that the deterioration of the electrolytic unit 20 is progressing and that replacement of the electrolytic unit 20 is necessary, it notifies the user of information regarding the replacement of the electrolytic unit 20. This information regarding the replacement of the electrolytic unit 20 may be displayed on the display, for example.

[0029] [C] Operation of the hydrogen production equipment degradation detection system The operation of the hydrogen production apparatus deterioration detection system 100 of this embodiment when detecting deterioration of the hydrogen production apparatus 1 will be described below.

[0030] [C-1] Input of current measurement value DI, electrolytic unit voltage measurement value DV, and electrolytic unit temperature measurement value DT When detecting deterioration of the hydrogen production apparatus 1, the current measurement value DI, the electrolytic unit voltage measurement value DV, and the electrolytic unit temperature measurement value DT are first input as input data to the deterioration detection unit 120.

[0031] Figure 3A shows the current measurement value DI, electrolytic unit voltage measurement value DV, and electrolytic unit temperature measurement value DT input to the degradation detection unit 120 in the hydrogen production apparatus degradation detection system 100 according to the first embodiment. In Figure 3A, the horizontal axis represents time t (s), and the vertical axis of each graph represents the current measurement value DI (A), the electrolytic unit voltage measurement value DV (V), and the electrolytic unit temperature measurement value DT (°C), respectively.

[0032] In this embodiment, when deterioration of the hydrogen production apparatus 1 is detected, the power supply unit 10 supplies power to the electrolysis unit 20 by step input, as shown in Figure 3A.

[0033] Specifically, the power supply unit 10 initially supplies a current of a first current value Ia to the electrolytic unit 20, and then at a first time point t1, supplies a current of a second current value Ib, which is different from the first current value Ia, to the electrolytic unit 20. Here, the second current value Ib is shown to be higher than the first current value Ia. The difference between the first current value Ia and the second current value Ib is converted to a current density of 0.1 A / cm². 2 It is preferable that it be to this extent. Subsequently, the power supply unit 10 returns to a state in which it supplies a current of the first current value Ia to the electrolytic unit 20 at a second time point t2, after a predetermined time ts has elapsed from the first time point t1. In other words, the current measurement value DI(A) rises from the first current value Ia to the second current value Ib at the first time point t1, and then falls from the second current value Ib to the first current value Ia at the second time point t2 (Ia <Ib)。

[0034] The electrolytic section voltage measurement value DV is the first electrolytic section voltage measurement value Va when a current of the first current value Ia is supplied to the electrolytic section 20 before the first time point t1. When the current is switched from the first current value Ia to the second current value Ib at the first time point t1, the electrolytic section voltage measurement value DV increases from the first electrolytic section voltage measurement value Va to the second electrolytic section voltage measurement value Vb (maximum value). Between the first time point t1 and the second time point t2 (ts), the electrolytic section voltage measurement value DV decreases from the second electrolytic section voltage measurement value Vb to the third electrolytic section voltage measurement value Vc as time t progresses. When the current is switched from the second current value Ib to the first current value Ia at the second time point t2, the electrolytic section voltage measurement value DV decreases from the third electrolytic section voltage measurement value Vc to the fourth electrolytic section voltage measurement value Vd (minimum value). Then, after the second time point t2, the electrolytic voltage measurement DV increases from the fourth electrolytic voltage measurement Vd to the first electrolytic voltage measurement Va as time t progresses (Vb>Vc>Va>Vd).

[0035] The electrolytic unit temperature measurement value DT (°C) is the first electrolytic unit temperature measurement value Ta when a current of the first current value Ia is supplied to the electrolytic unit 20 before the first time point t1. Then, from the time point t1 when the current is switched from the first current value Ia to the second current value Ib until the second time point t2 (ts), the electrolytic unit temperature measurement value DT (°C) increases from the first electrolytic unit temperature measurement value Ta to the second electrolytic unit temperature measurement value Tb as time t progresses. Then, after the second time point t2, the electrolytic unit temperature measurement value DT (°C) decreases from the second electrolytic unit temperature measurement value Tb to the first electrolytic unit temperature measurement value Ta as time t progresses (Tb > Ta).

[0036] [C-2] Degradation detection of hydrogen production equipment 1 Next, the degradation detection unit 120 detects the degradation of the hydrogen production apparatus 1 based on the current measurement value DI, the electrolytic unit voltage measurement value DV, and the electrolytic unit temperature measurement value DT.

[0037] Here, the degradation detection unit 120 obtains a first electrolytic section voltage measurement value Va and a second electrolytic section voltage measurement value Vb from the electrolytic section voltage measurement value DV input from the voltmeter 12. The first electrolytic section voltage measurement value Va and the second electrolytic section voltage measurement value Vb are selected based on the input of a first current value Ia and a second current value Ib. Then, the degradation detection unit 120 calculates the difference between the first electrolytic section voltage measurement value Va and the second electrolytic section voltage measurement value Vb as the electrolytic section voltage difference value ΔV.

[0038] Along with this, the degradation detection unit 120 obtains a first electrolytic section temperature measurement value Ta and a second electrolytic section temperature measurement value Tb from the electrolytic section temperature measurement value DT (°C) input from the thermometer 13. The first electrolytic section temperature measurement value Ta and the second electrolytic section temperature measurement value Tb are selected based on the input of a first current value Ia and a second current value Ib. The degradation detection unit 120 then calculates the difference between the first electrolytic section temperature measurement value Ta and the second electrolytic section temperature measurement value Tb as the electrolytic section temperature difference value ΔT. Furthermore, the degradation detection unit 120 calculates the electrolytic section temperature change rate HT (=ΔT / t) by dividing the electrolytic section temperature difference value ΔT by the time ts between the first time point t1 and the second time point t2.

[0039] Figure 3B shows the electrolytic section voltage difference value ΔV and the electrolytic section temperature change rate HT (=ΔT / t) determined by the degradation detection unit 120 in the hydrogen production apparatus degradation detection system 100 according to the first embodiment. In Figure 3B, the horizontal axis represents time t(d), and the vertical axis of each graph represents the electrolytic section voltage difference value ΔV and the electrolytic section temperature change rate HT (=ΔT / t), respectively.

[0040] The electrolytic voltage difference value ΔV, as shown in Figure 3B, is a value that increases with the passage of time t(d), and increases as the deterioration of the electrolytic unit 20 progresses. Specifically, the electrolytic voltage difference value ΔV increases as the electrolytic unit 20 deteriorates due to factors such as changes in the microstructure of the cells constituting the electrolytic unit and the accumulation of impurities in the cells, which increase the cell resistance.

[0041] As shown in Figure 3B, the rate of temperature change HT (=ΔT / t) of the electrolytic unit, like the voltage difference value ΔV of the electrolytic unit, is a value that increases with the passage of time t(d), and increases as the deterioration of the electrolytic unit 20 progresses. Specifically, the rate of temperature change HT (=ΔT / t) of the electrolytic unit increases as the electrolytic unit 20 deteriorates because the amount of heat generated from the cells increases as the cell resistance increases during electrolysis, leading to an increase in Joule heat from the cells when current is applied.

[0042] Thus, in this embodiment, the degradation detection unit 120 determines the voltage difference value ΔV and the temperature change rate HT (=ΔT / t) of the electrolytic unit as values ​​that quantitatively indicate the degradation state of the electrolytic unit 20.

[0043] [C-3] Hochi Next, based on the deterioration detected by the deterioration detection unit 120, the notification unit 140 notifies that the electrolytic unit 20 should be replaced.

[0044] Here, information regarding the electrolytic unit voltage difference value ΔV and the electrolytic unit temperature change rate HT (=ΔT / t) is input from the degradation detection unit 120 to the notification unit 140 as a result of degradation detection. As shown in Figure 3B, the notification unit 140 determines whether the electrolytic unit voltage difference value ΔV exceeds the threshold TH1. Also, as shown in Figure 3B, the notification unit 140 determines whether the electrolytic unit temperature change rate HT (=ΔT / t) exceeds the threshold TH2. Thresholds TH1 and TH2 are recommended values ​​for replacing the electrolytic unit 20 and are determined, for example, based on the results of tests conducted in advance.

[0045] The notification unit 140 notifies the user that the electrolytic unit 20 needs to be replaced if at least one of the electrolytic unit voltage difference value ΔV and the electrolytic unit temperature change rate HT (=ΔT / t) exceeds the threshold values ​​TH1 and TH2.

[0046] [D] Summary As described above, in the hydrogen production apparatus degradation detection system 100 of this embodiment, the degradation detection unit 120 detects the degradation of the electrolytic unit 20 based on the electrolytic unit voltage measurement value DV obtained by measuring the voltage of the electrolytic unit 20 when current is supplied from the power supply unit 10 to the electrolytic unit 20, and the electrolytic unit temperature measurement value DT obtained by measuring the temperature of the electrolytic unit 20.

[0047] Here, the power supply unit 10, which was supplying a current of a first current value Ia to the electrolytic unit 20, supplies a current of a second current value Ib, which is different from the first current value Ia, to the electrolytic unit 20 at a first time point t1. Subsequently, at a second time point t2, the power supply unit 10 returns to the state of supplying a current of the first current value Ia to the electrolytic unit 20.

[0048] At this time, the degradation detection unit 120 calculates the difference between the first electrolytic unit voltage measurement value Va, which is obtained when a current of the first current value Ia is supplied to the electrolytic unit 20 before the first time point t1, and the second electrolytic unit voltage measurement value Vb, which is measured as it fluctuates immediately after the current is switched from the current of the first current value Ia to the current of the second current value Ib at the first time point t1, as the electrolytic unit voltage difference value ΔV.

[0049] In conjunction with this, the degradation detection unit 120 calculates the difference between the first electrolytic unit temperature measurement value Ta, obtained when a current of the first current value Ia was supplied to the electrolytic unit 20 before the first time point t1, and the second electrolytic unit temperature measurement value Tb, measured when the current is switched from the second current value Ib to the first current value Ia at the second time point t2, as the electrolytic unit temperature difference value ΔT. Furthermore, the degradation detection unit 120 calculates the electrolytic unit temperature change rate HT (=ΔT / t) by dividing the electrolytic unit temperature difference value ΔT by the time ts between the first time point t1 and the second time point t2.

[0050] The degradation detection unit 120 then detects the degradation of the electrolytic unit 20 according to the voltage difference value ΔV and the temperature change rate HT (=ΔT / t) of the electrolytic unit. The voltage difference value ΔV and the temperature change rate HT (=ΔT / t) of the electrolytic unit fluctuate as the resistance and other parameters increase due to the degradation of the electrolytic unit 20.

[0051] Therefore, according to the hydrogen production apparatus deterioration detection system 100 of this embodiment, deterioration of the hydrogen production apparatus 1 equipped with the electrolysis unit 20 can be easily detected.

[0052] In addition, in the hydrogen production apparatus degradation detection system 100 of this embodiment, the notification unit 140 notifies the user that the electrolytic unit 20 should be replaced when at least one of the electrolytic unit voltage difference value ΔV and the electrolytic unit temperature change rate HT (=ΔT / t) exceeds a predetermined threshold. Therefore, in this embodiment, the user can easily understand when the electrolytic unit 20 needs to be replaced.

[0053] [E] Comparative Example Figure 4 shows the current measurement value DI, electrolytic section voltage measurement value DV, and electrolytic section temperature measurement value DT input to the degradation detection unit 120 in the comparative example. In Figure 4, the horizontal axis represents time t(s), and the vertical axis of each graph represents the current measurement value DI(A), the electrolytic section voltage measurement value DV(V), and the electrolytic section temperature measurement value DT(°C), respectively. In Figure 4, for each of the current measurement value DI(A), electrolytic section voltage measurement value DV(V), and electrolytic section temperature measurement value DT(°C), the comparative example is shown with a "solid line," and the embodiment described above (see Figure 3A) is shown with a "dotted line."

[0054] In this comparative example, as shown in Figure 4, the power supply unit 10, similar to the above embodiment (see Figure 3A), initially supplies a current of a first current value Ia to the electrolytic unit 20, and then at a first time point t1, supplies a current of a second current value Ib, which is different from the first current value Ia, to the electrolytic unit 20. However, in this comparative example, unlike the above embodiment (see Figure 3A), after the first time point t1, the power supply unit 10 maintains the current supplied to the electrolytic unit 20 at the second current value Ib.

[0055] The electrolytic voltage measurement value DV is the first electrolytic voltage measurement value Va when a current of the first current value Ia is supplied to the electrolytic unit 20 before the first time point t1, similar to the embodiment described above (see Figure 3A). Then, when the current is switched from the first current value Ia to the second current value Ib at the first time point t1, the electrolytic voltage measurement value DV increases from the first electrolytic voltage measurement value Va to the second electrolytic voltage measurement value Vb (maximum value). However, after the first time point t1, unlike the embodiment described above (see Figure 3A), the electrolytic voltage measurement value DV decreases from the second electrolytic voltage measurement value Vb as time t progresses, and maintains a constant electrolytic voltage measurement value Vbh.

[0056] The electrolytic unit temperature measurement value DT (°C) is the first electrolytic unit temperature measurement value Ta when a current of the first current value Ia is supplied to the electrolytic unit 20 before the first time point t1, similar to the above embodiment (see Figure 3A). However, after switching from the current of the first current value Ia to the current of the second current value Ib at the first time point t1, the electrolytic unit temperature measurement value DT (°C) increases from the first electrolytic unit temperature measurement value Ta as time t progresses, unlike the above embodiment (see Figure 3A), and maintains a constant electrolytic unit temperature measurement value Tbh.

[0057] In the comparative example, the electrolytic section voltage difference value ΔV, which is the difference between the first electrolytic section voltage measurement value Va and a constant electrolytic section voltage measurement value Vbh, can be determined as a value that quantitatively indicates the deterioration state of the electrolytic section 20. Also, in the comparative example, the electrolytic section temperature difference value ΔT, which is the difference between the first electrolytic section temperature measurement value Ta and a constant electrolytic section temperature measurement value Tbh, can be determined as a value that quantitatively indicates the deterioration state of the electrolytic section 20.

[0058] However, the time required to obtain a constant electrolytic section voltage measurement Vbh and a constant electrolytic section temperature measurement Tbh is, for example, several tens of minutes. The time required to obtain a constant electrolytic section voltage measurement Vbh and a constant electrolytic section temperature measurement Tbh is longer than the time required to obtain a second electrolytic section voltage measurement Vb and a second electrolytic section temperature measurement Tb.

[0059] Therefore, in this comparative example, if the power supply unit 10 supplies the same current value for a long period of time, it is possible to detect the deterioration of the hydrogen production apparatus 1, but if the current value is changed in a short period of time, it is difficult to detect the deterioration of the hydrogen production apparatus 1. However, in the above embodiment, even when the power supply unit 10 changes the current value in a short period of time, it is possible to easily detect the deterioration of the hydrogen production apparatus 1.

[0060] [F] Variation [F-1] Variation 1-1 Figure 5 shows the current measurement value DI, electrolytic section voltage measurement value DV, and electrolytic section temperature measurement value DT input to the degradation detection unit 120 in Modification 1-1. In Figure 5, the horizontal axis represents time t(s), and the vertical axis of each graph represents the current measurement value DI(A), the electrolytic section voltage measurement value DV(V), and the electrolytic section temperature measurement value DT(°C), respectively.

[0061] In this modified example, when deterioration of the hydrogen production apparatus 1 is detected, the power supply unit 10 supplies power to the electrolysis unit 20 by step input, as shown in Figure 5, similar to the above embodiment (Figure 3A). In the above embodiment (Figure 3A), the case in which the first current value Ia is smaller than the second current value Ib was described, but as in this modified example, the first current value Ia may be larger than the second current value Ib.

[0062] Specifically, in this modified example, the current measurement value DI(A) decreases from the first current value Ia to the second current value Ib at the first time point t1, and then increases from the second current value Ib to the first current value Ia at the second time point t2 (Ia > Ib).

[0063] The electrolytic section voltage measurement value DV is the first electrolytic section voltage measurement value Va when a current of the first current value Ia is supplied to the electrolytic section 20 before the first time point t1. When the current is switched from the first current value Ia to the second current value Ib at the first time point t1, the electrolytic section voltage measurement value DV decreases from the first electrolytic section voltage measurement value Va to the second electrolytic section voltage measurement value Vb (minimum value). Between the first time point t1 and the second time point t2 (ts), the electrolytic section voltage measurement value DV increases from the second electrolytic section voltage measurement value Vb to the third electrolytic section voltage measurement value Vc as time t progresses. When the current is switched from the second current value Ib to the first current value Ia at the second time point t2, the electrolytic section voltage measurement value DV increases from the third electrolytic section voltage measurement value Vc to the fourth electrolytic section voltage measurement value Vd (maximum value). Then, after the second time point t2, the electrolytic section voltage measurement DV decreases from the fourth electrolytic section voltage measurement Vd to the first electrolytic section voltage measurement Va (Vb) as time t progresses. <Vc<Va<Vd)。

[0064] The electrolytic unit temperature measurement value DT (°C) is the first electrolytic unit temperature measurement value Ta when a current of the first current value Ia is supplied to the electrolytic unit 20 before the first time point t1. Then, from the time point t1 when the current is switched from the first current value Ia to the second current value Ib until the second time point t2 (ts), the electrolytic unit temperature measurement value DT (°C) decreases from the first electrolytic unit temperature measurement value Ta to the second electrolytic unit temperature measurement value Tb as time t progresses. Then, after the second time point t2, the electrolytic unit temperature measurement value DT (°C) increases from the second electrolytic unit temperature measurement value Tb to the first electrolytic unit temperature measurement value Ta (Tb <Ta)。

[0065] In this modified example, the degradation detection unit 120 calculates the difference between the first electrolytic section voltage measurement value Va and the second electrolytic section voltage measurement value Vb as the electrolytic section voltage difference value ΔV. At the same time, the degradation detection unit 120 calculates the difference between the first electrolytic section temperature measurement value Ta and the second electrolytic section temperature measurement value Tb as the electrolytic section temperature difference value ΔT, and calculates the electrolytic section temperature change rate HT (=ΔT / t) by dividing the electrolytic section temperature difference value ΔT by the time ts between the first time point t1 and the second time point t2.

[0066] Thus, in this modified example as well, the voltage difference value ΔV of the electrolytic section and the temperature change rate HT (=ΔT / t) of the electrolytic section can be determined as values ​​that quantitatively indicate the deterioration state of the electrolytic section 20.

[0067] [F-2] Modification 1-2 Figure 6 is a diagram illustrating modified example 1-2. In Figure 6, the horizontal axis shows the current density ID (A / cm2) when current is supplied to the electrolytic unit 20, and the vertical axis shows the temperature T (°C) of the electrolytic unit 20.

[0068] As shown in Figure 6, when the current density ID (A / cm2) is increased from zero, the temperature T (°C) of the electrolytic unit 20 decreases from the initial temperature value T0 to the minimum temperature value Tmin, and then rises from the minimum temperature value Tmin. The range in which the temperature T (°C) of the electrolytic unit 20 decreases from the initial temperature value T0 to the minimum temperature value Tmin (ID is 0 to ID) TminIn the electrolytic section 20, an endothermic reaction occurs. In contrast, in the range where the temperature T (°C) of the electrolytic section 20 rises from the lowest temperature value Tmin (ID is ID Tmin In the range exceeding this value, heat is generated in the electrolytic section 20.

[0069] In the above embodiment, it is preferable that the current supplied to the electrolytic unit 20, with a first current value Ia and a second current value Ib, are current values ​​that cause heat generation in the electrolytic unit 20 (see Figure 3A). In other words, the current density ID (A / cm2) at the first current value Ia and the second current value Ib is the current density ID at which the temperature T (°C) of the electrolytic unit 20 changes from decreasing to increasing. Tmin It is preferable to exceed this value. This makes it possible to more accurately grasp the deterioration state of the electrolytic unit 20.

[0070] [F-3] Other variations In the above embodiment, a case was described in which the degradation detection unit 120 detects degradation of the electrolytic unit 20 based on the electrolytic unit voltage measurement value DV and the electrolytic unit temperature measurement value DT, but it is not limited to this. The degradation detection unit 120 may be configured to detect degradation of the electrolytic unit 20 based on the electrolytic unit voltage measurement value DV.

[0071] The time ts between the first time point t1 and the second time point t2 is not particularly limited, but when detecting deterioration of the electrolytic unit 20 based on the electrolytic unit voltage measurement value DV, it is preferably about 10 to 30 seconds. Furthermore, when detecting deterioration of the electrolytic unit 20 based on the electrolytic unit temperature measurement value DT, it is preferable that the time ts between the first time point t1 and the second time point t2 be 1 minute or more.

[0072] <Second Embodiment> [A] Configuration of the hydrogen production equipment degradation detection system Figure 7 is a schematic diagram showing the configuration of the hydrogen production apparatus degradation detection system 100 according to the second embodiment. Figure 7 shows the relationship between the hydrogen production apparatus degradation detection system 100 and a part of the hydrogen production apparatus 1 (see Figure 1).

[0073] As shown in Figure 7, in this embodiment, the hydrogen production apparatus 1 is equipped with a plurality of electrolytic units 20. The hydrogen production apparatus degradation detection system 100 of this embodiment receives the electrolytic unit voltage measurement value DV and the electrolytic unit temperature measurement value DT, which are measured for each of the plurality of electrolytic units 20, as input signals. In addition, the hydrogen production apparatus degradation detection system 100 of this embodiment also receives the power supply unit voltage measurement value VM, which is obtained by measuring the voltage of the power supply unit 10 with a voltmeter 14 when the power supply unit 10 is performing power supply, as an input signal. Except for this point and related points, this embodiment is the same as the above embodiment. For this reason, explanations of overlapping matters will be omitted as appropriate.

[0074] In the hydrogen production apparatus degradation detection system 100 of this embodiment, the degradation detection unit 120 receives the electrolytic unit voltage measurement value DV and the electrolytic unit temperature measurement value DT, which are measured for each of the multiple electrolytic units 20. The degradation detection unit 120 then uses the electrolytic unit voltage measurement value DV and the electrolytic unit temperature measurement value DT, which are measured for each of the multiple electrolytic units 20, to detect the degradation of the multiple electrolytic units 20, in the same manner as in the above embodiment.

[0075] In this embodiment, unlike the above embodiment, the degradation detection unit 120 receives the power supply voltage measurement value VM, which is measured for the voltage of the power supply unit 10, as input. The degradation detection unit 120 is configured to detect the degradation of parts of the hydrogen production apparatus 1 other than the electrolysis unit 20 based on the power supply voltage measurement value VM and the electrolysis unit voltage measurement value DV.

[0076] Figure 8A shows the current measurement value DI, electrolytic unit voltage measurement value DV, and power supply unit voltage measurement value VM input to the degradation detection unit 120 in the hydrogen production apparatus degradation detection system 100 according to the second embodiment. In Figure 8A, the horizontal axis represents time t(s), and the vertical axis of each graph represents the current measurement value DI(A), the electrolytic unit voltage measurement value DV(V), and the power supply unit voltage measurement value VM(V), respectively.

[0077] In this embodiment, when deterioration of the hydrogen production apparatus 1 is detected, as shown in Figure 7, the power supply unit 10 supplies power to the electrolysis unit 20 by step input, similar to the case in the first embodiment. As a result, the electrolysis unit voltage measurement value DV changes in the same way as in the case in the first embodiment.

[0078] The power supply voltage measurement value VM is the first power supply voltage measurement value VMa when a current of the first current value Ia is supplied to the electrolytic unit 20 before the first time point t1. When the current is switched from the first current value Ia to the second current value Ib at the first time point t1, the power supply voltage measurement value VM increases from the first power supply voltage measurement value VMa to the second power supply voltage measurement value VMb (maximum value). Between the first time point t1 and the second time point t2 (ts), the power supply voltage measurement value VM decreases from the second power supply voltage measurement value VMb to the third power supply voltage measurement value VMc as time t progresses. When the current is switched from the second current value Ib to the first current value Ia at the second time point t2, the power supply voltage measurement value VM decreases from the third power supply voltage measurement value VMc to the fourth power supply voltage measurement value VMd (minimum value). Then, after the second time point t2, the power supply voltage measurement VM increases from the fourth power supply voltage measurement VMd to the first power supply voltage measurement VMa as time t progresses (VMb > VMc > VMa > VMd).

[0079] As described above, the degradation detection unit 120 detects degradation based on the power supply voltage measurement value VM and the electrolytic unit voltage measurement value DV.

[0080] Here, the degradation detection unit 120 obtains a third power supply voltage measurement value VMc from the power supply voltage measurement values ​​VM. The degradation detection unit 120 also obtains a third electrolytic unit voltage measurement value Vc from the electrolytic unit voltage measurement values ​​DV. The degradation detection unit 120 then calculates the difference between the third power supply voltage measurement value VMc and the third electrolytic unit voltage measurement value Vc as the power supply voltage difference value ΔVM, and detects degradation according to this power supply voltage difference value ΔVM.

[0081] Figure 8B shows the power supply voltage difference value ΔVM obtained by the degradation detection unit 120 in the hydrogen production apparatus degradation detection system 100 according to the second embodiment. In Figure 8B, the horizontal axis represents time t(d), and the vertical axis of each graph represents the power supply voltage difference value ΔVM.

[0082] The power supply voltage difference value ΔVM normally remains constant, but it increases due to deterioration of the current supply line L11. For example, if the resistance increases due to deterioration of the current supply line L11 itself, or if loosening occurs between the current supply line L11 and other parts, resulting in insufficient connection, the power supply voltage difference value ΔVM will fluctuate from a constant value, as shown in Figure 8B.

[0083] Thus, in this embodiment, the degradation detection unit 120 determines the power supply voltage difference value ΔVM as a value that quantitatively indicates the degradation state of the current supply line L11.

[0084] [B] Summary As described above, in this embodiment, the degradation detection unit 120 detects the degradation of parts of the hydrogen production apparatus 1 other than the electrolytic unit 20 based on the power supply unit voltage measurement value VM obtained by measuring the voltage of the power supply unit 10 when the power supply unit 10 is supplying power, and the electrolytic unit voltage measurement value DV obtained by measuring the voltage of the electrolytic unit 20 when the power supply unit 10 is supplying power.

[0085] Therefore, according to the hydrogen production apparatus deterioration detection system 100 of this embodiment, deterioration of the hydrogen production apparatus 1 can be easily detected.

[0086] <Other> While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of Symbols]

[0087] 1: Hydrogen production equipment, 10: Power supply unit, 11: Ammeter, 12: Voltmeter, 13: Thermometer, 14: Voltmeter, 20: Electrolysis unit, 21: Electrolytic cell, 22: Electrolytic cell stack container, 40: Water supply source, 41: Hydrogen supply source, 50: Steam generation unit, 60: Heat exchanger, 70: Separation unit, 80: Dilution gas source, 100: Hydrogen production equipment degradation detection system, 120: Degradation detection unit, 140: Notification unit, DI: Current measurement value, DT: Electrolysis unit temperature measurement value, DV: Electrolysis unit voltage measurement value, HT: Electrolysis unit temperature change rate, Ia: First current value, Ib: Second current value, ID: Current density, L11: Current supply line, L21a: Piping, L21b: Piping, L40: Piping, L41: Piping, L50: Piping, L60: Piping, L70a: Piping, L80: Piping, t1: First time point, t2: Second time point, Ta: First electrolytic unit temperature measurement, Tb: Second electrolytic unit temperature measurement, TH1: Threshold, TH2: Threshold, Tmin: Minimum temperature value, ts: Time, Va: First electrolytic unit voltage measurement, Vb: Second electrolytic unit voltage measurement, Vc: Third electrolytic unit voltage measurement, Vd: Fourth electrolytic unit voltage measurement, VM: Power supply voltage measurement, VMa: First power supply voltage measurement, VMb: Second power supply voltage measurement, VMc: Third power supply voltage measurement, VMd: Fourth power supply voltage measurement, VMV: Power supply voltage measurement, ΔT: Electrolytic unit temperature difference, ΔV: Electrolytic unit voltage difference, ΔVM: Power supply voltage difference

Claims

1. A hydrogen production apparatus degradation detection system for detecting degradation of a hydrogen production apparatus configured to perform electrolysis of water by supplying current to the electrolysis unit via a current supply line from a power supply unit, A deterioration detection unit is configured to detect deterioration of the electrolytic unit based on an electrolytic unit voltage measurement value obtained by measuring the voltage of the electrolytic unit when current is supplied from the power supply unit to the electrolytic unit. Equipped with, The power supply unit performs power supply such that, starting from a state in which it supplies a current of a first current value to the electrolytic unit, it supplies a current of a second current value different from the first current value to the electrolytic unit at a first time point, and then returns to a state in which it supplies a current of the first current value to the electrolytic unit at a second time point. The deterioration detection unit determines the difference between a first electrolytic unit voltage measurement value obtained when the current of the first current value is supplied to the electrolytic unit before the first time point, and a second electrolytic unit voltage measurement value obtained when the current of the first current value is switched to the current of the second current value at the first time point, and detects deterioration of the electrolytic unit according to the electrolytic unit voltage difference value. Hydrogen production equipment degradation detection system.

2. The first current value and the second current value are current values ​​at which heat is generated in the electrolytic unit. A hydrogen production apparatus deterioration detection system according to claim 1.

3. A notification unit is configured to notify the replacement of the electrolytic unit when the voltage difference value of the electrolytic unit exceeds a predetermined threshold. Having, A hydrogen production apparatus deterioration detection system according to claim 1.

4. The aforementioned deterioration detection unit The system is configured to detect deterioration of the electrolytic unit based on an electrolytic unit temperature measurement obtained by measuring the temperature of the electrolytic unit when current is supplied from the power supply unit to the electrolytic unit. The difference between the first electrolytic unit temperature measurement value obtained when the current of the first current value was supplied to the electrolytic unit before the first time point and the second electrolytic unit temperature measurement value obtained when the current of the second current value was switched to the current of the first current value at the second time point is calculated as the electrolytic unit temperature difference value, and the value obtained by dividing the electrolytic unit temperature difference value by the time ts between the first time point and the second time point is calculated as the electrolytic unit temperature change rate. The deterioration of the electrolytic unit is detected according to the rate of temperature change of the electrolytic unit. A hydrogen production apparatus deterioration detection system according to claim 1.

5. A notification unit is configured to notify the replacement of the electrolytic unit when at least one of the voltage difference value of the electrolytic unit and the temperature change rate of the electrolytic unit exceeds a predetermined threshold. Having, Hydrogen production apparatus deterioration detection system according to claim 4.

6. The deterioration detection unit is configured to detect deterioration of the hydrogen production apparatus based on a power supply voltage measurement obtained by measuring the voltage of the power supply unit while the power supply unit is performing the power supply, and an electrolytic unit voltage measurement obtained by measuring the voltage of the electrolytic unit while the power supply unit is performing the power supply. A hydrogen production apparatus deterioration detection system according to claim 1.

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