Water electrolysis method

Abstract

An object of the present disclosure is to provide a water electrolysis method that facilitates heat control of a water electrolysis stack group. [Solution] The water electrolysis method includes combining multiple water electrolysis stacks 62 with different degrees of deterioration to form a water electrolysis stack group 20, and obtaining hydrogen using water electrolysis equipment 10 including the water electrolysis stack group 20.

Description

[Technical Field]

[0001] The present disclosure relates to a water electrolysis method. [Background technology]

[0002] For example, Patent Document 1 discloses a water electrolysis system including n (n is an integer greater than or equal to 1) solid polymer water electrolysis stacks, the water electrolysis system including: a power supply unit capable of individually distributing input power input from a power source to each of the n water electrolysis stacks; and a control unit that selects m (1 is an integer less than or equal to 1) water electrolysis stacks from the n water electrolysis stacks and controls the power supply unit to supply power at a current equal to or greater than a lower limit current value to each of the m water electrolysis stacks, where the lower limit current value is a current value at which the current efficiency of the water electrolysis stacks is 98% or greater and the overall power efficiency, which is the product of the power supply efficiency of the power source and the power efficiency of the water electrolysis stacks, is maximized, and m is determined based on the input power and is the maximum number of the m water electrolysis stacks that can be supplied with power at the lower limit current value. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-181605 Summary of the Invention [Problem to be solved by the invention]

[0004] In water electrolysis equipment, the amount of heat generated by a water electrolysis stack varies greatly between the start of use and the end of its life. For this reason, it is necessary to narrow the range of control over the heat generated by the water electrolysis stack in water electrolysis equipment. However, the technology described in Patent Document 1 is prone to large differences in the amount of heat generated between the start of use and the end of its life.

[0005] An object of the present disclosure is to provide a water electrolysis method that facilitates heat control of a water electrolysis stack group. [Means for solving the problem]

[0006] A first aspect of the water electrolysis method includes: configuring a water electrolysis stack group by combining a plurality of water electrolysis stacks having different degrees of deterioration; and obtaining hydrogen using water electrolysis equipment including the water electrolysis stack group.

[0007] In the water electrolysis method of this aspect, the water electrolysis stack group is configured by combining multiple water electrolysis stacks with different degrees of deterioration. As a result, this water electrolysis method can reduce the fluctuation range of the control range of heat generated by the water electrolysis stack group in the water electrolysis process, compared to a case in which multiple water electrolysis stack groups are combined so that the degrees of deterioration of the multiple water electrolysis stacks included in the water electrolysis stack group are all the same. In other words, this water electrolysis method facilitates heat control of the water electrolysis stack group.

[0008] In a second aspect of the water electrolysis method, in the water electrolysis method according to the first aspect, a plurality of the water electrolysis stack groups are used in the water electrolysis facility, and the water electrolysis stack groups are configured by replacing water electrolysis stacks included in different water electrolysis stack groups, so that the degrees of deterioration of the respective water electrolysis stack groups are kept within a predetermined range.

[0009] In the water electrolysis method of this aspect, a plurality of water electrolysis stack groups are used, and water electrolysis stacks included in different water electrolysis stack groups are replaced with each other to form water electrolysis stack groups. The degree of deterioration of each of the plurality of water electrolysis stack groups is set to fall within a predetermined range. This facilitates control of heat generated from each water electrolysis stack group in a water electrolysis process using the plurality of water electrolysis stack groups. [Effects of the Invention]

[0010] According to the present disclosure, it is possible to provide a water electrolysis method that facilitates heat control of a water electrolysis stack group. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram showing a water electrolysis facility according to an embodiment. [Figure 2] FIG. 2 is a diagram illustrating a control device included in the water electrolysis facility. [Figure 3] FIG. 1 is a diagram illustrating replacement of a water electrolysis stack in a water electrolysis stack group in a water electrolysis facility. [Figure 4] 5 is a diagram illustrating replacement of a water electrolysis stack in a water electrolysis stack group, following FIG. 3, in which a water electrolysis stack included in one water electrolysis stack group is replaced with a water electrolysis stack included in another water electrolysis stack group. [Figure 5] FIG. 1 is a schematic diagram showing the amount of heat generated from a water electrolysis stack group in water electrolysis equipment according to an embodiment, illustrating changes in the amount of heat generated when water electrolysis stacks with different degrees of deterioration are not combined with the water electrolysis stack group, and changes in the amount of heat generated when water electrolysis stacks with different degrees of deterioration are combined with the water electrolysis stack group; DETAILED DESCRIPTION OF THE INVENTION

[0012] An example of an embodiment of the present disclosure will be described below with reference to the drawings. In each drawing, the same or equivalent components and parts are designated by the same reference numerals. Furthermore, the dimensional proportions in the drawings are exaggerated for the sake of explanation and may differ from the actual proportions.

[0013] (composition) (Water electrolysis equipment 10) FIG. 1 shows a water electrolysis facility 10 according to an embodiment of the present disclosure. The water electrolysis facility 10 includes a pure water supply unit 70, a plurality of water electrolysis stack groups 20, a power supply unit 72 for operating the water electrolysis stacks 62, and a control device 32. In the description of this embodiment, when the water electrolysis stack groups 20 need to be distinguished, they are referred to as a first water electrolysis stack group 20A, a second water electrolysis stack group 20B, and a third water electrolysis stack group 20C based on FIG. 1 and other figures. When the first water electrolysis stack group 20A, the second water electrolysis stack group 20B, and the third water electrolysis stack group 20C are not distinguished from one another, they are simply referred to as "water electrolysis stack groups 20."

[0014] The pure water supply unit 70 is a component that supplies pure water to the plurality of water electrolysis stack groups 20 through a pure water supply line 78. The pure water supply unit 70 includes a pump and the like (not shown), and supplies pure water to each of the plurality of water electrolysis stack groups 20 under the control of the control device 32.

[0015] 1, the water electrolysis stack group 20 includes a housing 24, a temperature sensor 28, a plurality of water electrolysis stacks 62, and a cooling device 22. The housing 24 houses the plurality of water electrolysis stacks 62.

[0016] Each of the multiple water electrolysis stacks 62 is formed by stacking water electrolysis cells, each of which forms an anode and a cathode with an electrolyte membrane sandwiched between them. In the water electrolysis stacks 62, water supplied to the anode is electrolyzed by passing a current through the stacks, generating oxygen at the anode and hydrogen at the cathode. The water electrolysis stacks 62 are also connected to the control device 32 via a power supply 72, and the control device 32 controls the amount of current passing through the stacks, thereby controlling the amount of water electrolysis.

[0017] One end of a pure water supply line 78 is connected to the anode side inlet of the water electrolysis stack 62, and water is supplied from the pure water supply line 78. A hydrogen delivery line 80 is connected to the cathode side outlet of the water electrolysis stack 62, and hydrogen is delivered from the hydrogen delivery line 80. One end of a water / oxygen delivery line 82 is connected to the anode side outlet of the water electrolysis stack 62, and oxygen and undecomposed water are delivered from the water / oxygen delivery line 82.

[0018] The other end of the hydrogen delivery line 80 is connected to the hydrogen supply unit 76, and delivers hydrogen to the outside of the water electrolysis equipment 10. The hydrogen supplied from the hydrogen supply unit 76 may be used for any purpose.

[0019] The other end of the water / oxygen delivery line 82 is connected to the oxygen supply unit 74, and delivers oxygen to the outside of the water electrolysis equipment 10. The oxygen supplied from the oxygen supply unit 74 may be used for any purpose. Oxygen and water are separated in the water / oxygen delivery line 82. The water / oxygen delivery line 82 is also connected to the pure water supply unit 70, and the water separated from oxygen in the water / oxygen delivery line 82 is supplied to the pure water supply unit 70.

[0020] The cooling device 22 is a device that controls the temperature inside the housing 24. Any device may be used as the cooling device 22, and one example is a ventilation fan that ventilates between the inside and outside of the housing 24. The cooling device 22 operates based on instructions from the control device 32, as described below, and cools the multiple water electrolysis stacks 62 housed in the housing 24.

[0021] In the present embodiment, the cooling device 22 collectively cools the multiple water electrolysis stacks 62 housed in the housing 24. The number of cooling devices 22 per housing 24 is not limited to one, and multiple cooling devices 22 may be provided. The number of water electrolysis stacks 62 cooled by the cooling device 22 is not limited to two or more. The specific configuration of the cooling device 22 is not particularly limited, and examples include a water-cooling system using a coolant that contacts the water electrolysis stacks 62 and an air-cooling system that ventilates the air inside the housing 24 using a fan. For example, the cooling device 22 may be a heat exchanger provided in the pure water supply line 78. That is, the cooling device 22 is not limited to being disposed inside the housing 24, and may be configured to cool the temperature of the pure water supplied to the water electrolysis stacks 62.

[0022] The temperature sensor 28 measures the temperature of the water electrolysis stack group 20 housed in the housing 24. The temperature sensor 28 may be any device capable of measuring the temperature of the water electrolysis stack group 20. Examples of the temperature sensor 28 include a radiation thermometer and a thermistor.

[0023] Alternatively, the temperature of the water electrolysis stack group 20 may be measured indirectly based on other physical quantities rather than directly. For example, when the current supplied from the power supply device 72 to the water electrolysis stacks 62 is predetermined, a voltmeter may be attached to each water electrolysis stack 62, and the temperature may be measured indirectly by measuring the heat generation amount based on the measurement value of the voltmeter (i.e., the power consumption value).

[0024] The temperature measurement results of each water electrolysis stack group 20 obtained from the temperature sensor 28 are transmitted to the control device 32.

[0025] (Control device 32) The control device 32 is a device that controls the water electrolysis equipment 10. Fig. 2 is a block diagram showing the hardware configuration of the control device 32 in this embodiment. As shown in Fig. 2, the control device 32 includes a control unit 40, a temperature control unit 50, and a communication unit 56. These components are connected to each other via an input / output interface (I / O) 45.

[0026] The control unit 40 is a device that controls each part of the control device 32. The control unit 40 has the functions of a computer, and has a CPU 41 (Central Processing Unit), a RAM 42 (Random Access Memory), and a ROM 43 (Read Only Memory), as shown in Fig. 2. The CPU 41, RAM 42, and ROM 43 are connected to each other via a control bus 44.

[0027] The CPU 41 is a central processing unit that executes various programs including a program 46 such as an information synchronization program, and controls various components. The ROM 43 stores various programs 46 including the program 46 and various data. The RAM 42 serves as a working area and temporarily stores the program 46 or data.

[0028] In the control unit 40, the CPU 41 reads various programs including the program 46 from the ROM 43 and executes the program 46 using the RAM 42 as a work area. The CPU 41 executes the program 46 to realize various functions for controlling each part of the control device 32.

[0029] The temperature control unit 50 is a device that acquires the temperature of each water electrolysis stack group 20 and notifies the CPU 41 of the control unit 40 of the acquired temperature. The temperature control unit 50 is also a device that controls the temperature of the water electrolysis stack group 20 in accordance with instructions from the CPU 41. More specifically, the temperature control unit 50 acquires the temperature of each of the water electrolysis stack groups 20 based on the temperature sensors 28 and notifies the CPU 41. The temperature control unit 50 also drives the cooling device 22 to control the temperature of the water electrolysis stack group 20 in accordance with instructions from the CPU 41.

[0030] The communication unit 56 is a component for communicating with devices external to the water electrolysis equipment 10 based on instructions from the CPU 41. More specifically, as will be described later, the communication unit 56 communicates with other devices to notify a maintenance manager (not shown) of the water electrolysis equipment 10 of the status of the water electrolysis stack 62. Specifically, the communication unit 56 communicates with other devices using communication means such as wired, wireless, the Internet, an intranet, or a public line such as a telephone line. Note that the communication means may also be communication means using sound, light, vibration, images, or the like. The status of the water electrolysis equipment 10 is notified to a maintenance manager (not shown) of the water electrolysis equipment 10 via these communication means.

[0031] Next, a water electrolysis method in the water electrolysis equipment 10 according to the present disclosure will be described with reference to Figures 3 and 4. For simplicity of description, the water electrolysis stack 62, which is not shown (omitted), is not taken into consideration in Figures 3 and 4.

[0032] (Water electrolysis method) The water electrolysis method according to this embodiment includes a water electrolysis preparation process and a water electrolysis process.

[0033] (Water electrolysis preparation process) In the water electrolysis preparation process, a plurality of water electrolysis stacks 62 with different degrees of deterioration are combined to form a water electrolysis stack group 20. Figures 3 and 4 show an example of the water electrolysis preparation process.

[0034] Fig. 3 shows different degrees of deterioration of the water electrolysis stacks 62 in the multiple water electrolysis stack groups 20 included in the water electrolysis equipment 10 in Fig. 1. More specifically, Fig. 3 shows that the first water electrolysis stack group 20A, the second water electrolysis stack group 20B, and the third water electrolysis stack group 20C each have a water electrolysis stack 64 that is more deteriorated. Fig. 3 also shows that the first water electrolysis stack group 20A has a water electrolysis stack 66 that is more deteriorated than the water electrolysis stack 64 that is more deteriorated. Fig. 3 also shows that the second water electrolysis stack group 20B has a water electrolysis stack 68 that is more deteriorated than the further deteriorated water electrolysis stack 66 and has reached the end of its life.

[0035] (Deterioration of the water electrolysis stack 62) Here, when the water electrolysis stack 62 included in the water electrolysis stack group 20 deteriorates, the amount of power consumption required for water electrolysis tends to be larger than that at the initial stage (i.e., when the water electrolysis stack 62 is new). Specifically, when the water electrolysis stack 62 deteriorates, the voltage required for water electrolysis needs to be higher than that at the initial stage. Note that the current required for water electrolysis is the same in the initial stage and after deterioration.

[0036] Therefore, when the degree of deterioration of the water electrolysis stack 62 increases compared to the initial state, the amount of power consumed during water electrolysis also increases. In other words, the greater the degree of deterioration of the water electrolysis stack 62, the greater the amount of heat generated.

[0037] In the water electrolysis equipment 10 of this embodiment, the control unit 40 determines the degree of deterioration of each water electrolysis stack 62 included in the water electrolysis stack group 20. Specifically, the CPU 41 executes the program 46 to determine the degree of deterioration of the water electrolysis stack 62 from the amount of power consumed by the water electrolysis stack 62. The amount of power consumed is measured based on the results obtained by a voltmeter attached to each water electrolysis stack 62, for example.

[0038] In the water electrolysis equipment 10 of this embodiment, as shown in FIG. 3 , the deteriorated water electrolysis stack 64 in the first water electrolysis stack group 20A is replaced with the water electrolysis stack 62 in the second water electrolysis stack group 20B that is not deteriorated (i.e., generates a small amount of heat).

[0039] The water electrolysis stack 62 may be replaced in any manner. A first example of the method includes a method in which a transfer robot (not shown) replaces the deteriorated water electrolysis stack 64 in the first water electrolysis stack group 20A with the non-deteriorated water electrolysis stack 62 in the second water electrolysis stack group 20B. A second example of the method includes a method in which the CPU 41 of the control unit 40, based on the execution result of the program 46, causes the communication unit 56 to issue a notification urging the maintenance manager (not shown) of the water electrolysis equipment 10 to replace the water electrolysis stack 62. The maintenance manager of the water electrolysis equipment 10 then manually replaces the deteriorated water electrolysis stack 64 in the first water electrolysis stack group 20A with the non-deteriorated water electrolysis stack 62 in the second water electrolysis stack group 20B.

[0040] Fig. 4 shows a state in which a deteriorated water electrolysis stack 64 in the first water electrolysis stack group 20A is replaced with a non-deteriorated water electrolysis stack 62 in the second water electrolysis stack group 20B from the state shown in Fig. 3. In the state shown in Fig. 4, the second water electrolysis stack group 20B and the third water electrolysis stack group 20C each include two deteriorated water electrolysis stacks 64. In addition, the first water electrolysis stack group 20A includes one water electrolysis stack 66 that is further deteriorated.

[0041] 3 , when water electrolysis is performed after replacing the expired water electrolysis stack 68 in the second water electrolysis stack group 20B with a new water electrolysis stack 62, i.e., when the expired water electrolysis stack 68 is removed from the second water electrolysis stack group 20B and replaced with a new water electrolysis stack 62, the power consumption of the first water electrolysis stack group 20A is greater than that of the second water electrolysis stack group 20B and the third water electrolysis stack group 20C. Specifically, this is because the first water electrolysis stack group 20A includes a water electrolysis stack 64 that is more deteriorated than the second water electrolysis stack group 20B and the third water electrolysis stack group 20C, and a water electrolysis stack 66 that is more deteriorated than the deteriorated water electrolysis stack 64. On the other hand, the power consumption of the second water electrolysis stack group 20B is less than that of the first water electrolysis stack group 20A and the third water electrolysis stack group 20C. Specifically, the second water electrolysis stack group 20B includes fewer water electrolysis stacks 64 that are more deteriorated than the first water electrolysis stack group 20A and the third water electrolysis stack group 20C, and fewer water electrolysis stacks 66 that are more deteriorated than the deteriorated water electrolysis stacks 64.

[0042] Therefore, in the state shown in Fig. 4, the amount of heat generated by the first water electrolysis stack group 20A is smaller than that in the state shown in Fig. 3. Furthermore, the amount of heat generated by the second water electrolysis stack group 20B is greater than that in the state shown in Fig. 3 (see also Fig. 5 described below).

[0043] In the water electrolysis preparation process according to this embodiment, the degree of deterioration of each water electrolysis stack group 20 is set to a predetermined range. In this description, the degree of deterioration of each water electrolysis stack 62 is determined based on the power consumption of the water electrolysis stack 62. That is, in this embodiment, the water electrolysis stack 62 is replaced so that the average power consumption of the water electrolysis stacks 62 included in the water electrolysis stack group 20 falls within the predetermined range for the first water electrolysis stack group 20A, the second water electrolysis stack group 20B, and the third water electrolysis stack group 20C.

[0044] (Water electrolysis process) In the water electrolysis process, hydrogen is obtained using a water electrolysis equipment 10 including a water electrolysis stack group 20 formed by combining water electrolysis stacks 62 that have different degrees of deterioration due to the water electrolysis preparation process. In the water electrolysis process of this embodiment, the water electrolysis equipment 10 is used for water electrolysis from the state after the water electrolysis preparation process (the state shown in FIG. 4 ).

[0045] Specifically, as described above, pure water is supplied to each water electrolysis stack group 20 from the pure water supply line 78, and electricity is supplied to each water electrolysis stack group 20 from the power supply device 72. Then, as described above, hydrogen and oxygen produced by electrolyzing pure water in each water electrolysis stack group 20 are delivered to the hydrogen delivery line 80 and the water / oxygen delivery line 82, respectively.

[0046] In the water electrolysis process, each cooling device 22 cools the water electrolysis stack 62 included in the water electrolysis stack group 20. The amount of heat used to cool the water electrolysis stack 62 by the cooling device 22 corresponds to the amount of heat generated by the water electrolysis stack 62 included in the water electrolysis stack group 20.

[0047] (Supplementary information on water electrolysis) In the water electrolysis equipment 10 according to the present embodiment, the timing for replacing the water electrolysis stacks 62 included in the water electrolysis stack group 20 is not particularly limited. For example, the water electrolysis preparation process may be performed when a regular inspection of the water electrolysis equipment 10 is performed. Another example is when the water electrolysis preparation process is performed when any of the water electrolysis stacks 62 included in the water electrolysis equipment 10 is replaced.

[0048] Furthermore, in the water electrolysis preparation process described above, the power consumption of each water electrolysis stack 62 is measured, but the timing of measuring the power consumption is not particularly limited. In other words, the control unit 40 may obtain the power consumption of each water electrolysis stack 62 from the temperature control unit 50 at any time. For example, the control unit 40 may measure the power consumption of each water electrolysis stack 62 during the water electrolysis process (i.e., while water electrolysis is being performed).

[0049] Furthermore, for example, the method for determining the degree of deterioration of the water electrolysis stack 62 is not limited to measuring the amount of power consumption. For example, the degree of deterioration of the water electrolysis stack 62 may be determined by measuring the temperature difference between the pure water supplied to the water electrolysis stack 62 and the pure water discharged from the water electrolysis stack 62. More specifically, the control unit 40 may measure the temperature of the cooling water for the pure water in the pure water supply line 78 supplied to the water electrolysis stack 62 and the temperature of the pure water contained in the water oxygen delivery line 82, and determine that the degree of deterioration is more advanced when the temperature difference between these temperatures is greater, thereby determining the degree of deterioration of the water electrolysis stack 62.

[0050] In the above description, the water electrolysis stack 68 that has reached the end of its life in the second water electrolysis stack group 20B is replaced with a new water electrolysis stack 62, and then the deteriorated water electrolysis stack 64 in the first water electrolysis stack group 20A is replaced with another water electrolysis stack 62 different from the new water electrolysis stack 62. The manner of replacing the water electrolysis stack 62 in this embodiment is not particularly limited.

[0051] For example, the water electrolysis stack 68 that has reached the end of its life may be removed from the second water electrolysis stack group 20B, and the deteriorated water electrolysis stack 64 from the first water electrolysis stack group 20A may be replaced, and a new water electrolysis stack 62 may be installed in the location where the deteriorated water electrolysis stack 62 had been installed.

[0052] Furthermore, for example, although the water electrolysis stacks 62 are replaced between the first water electrolysis stack group 20A and the second water electrolysis stack group 20B in the above description, the water electrolysis stacks 62 may also be replaced including the third water electrolysis stack group 20C. For example, the water electrolysis stacks 62 may be replaced by moving the water electrolysis stacks 62 included in the first water electrolysis stack group 20A to the second water electrolysis stack group 20B, the water electrolysis stacks 62 included in the second water electrolysis stack group 20B to the third water electrolysis stack group 20C, and the water electrolysis stacks 62 included in the third water electrolysis stack group 20C to the first water electrolysis stack group 20A. In other words, the manner of replacement is not particularly limited as long as the degree of deterioration of the water electrolysis stack groups 20 included in the water electrolysis equipment 10 is within a predetermined range.

[0053] Next, the functions and effects of the water electrolysis equipment 10 and the water electrolysis method according to this embodiment will be described.

[0054] (Action and effect) Fig. 5 shows the difference in heat generation amount between a period of normal operation and a period when any of the water electrolysis stacks 62 is replaced when the water electrolysis stack group 20 does not include a combination of water electrolysis stacks 62 with different degrees of deterioration. Fig. 5 also shows the difference in heat generation amount between a period of normal operation and a period when any of the water electrolysis stacks 62 is replaced when the water electrolysis stack group 20 includes a combination of water electrolysis stacks 62 with different degrees of deterioration. Note that the "period of normal operation" here refers to a period when the water electrolysis stack 62 included in the water electrolysis stack group 20 does not need to be replaced, i.e., a period when it has not reached the end of its life.

[0055] As shown in Fig. 5 , the amount of heat generated by the water electrolysis stack group 20 during normal operation is greater when water electrolysis stacks 62 with different degrees of deterioration are combined than when water electrolysis stacks 62 with different degrees of deterioration are not combined. Here, if water electrolysis stacks 62 with different degrees of deterioration are not combined in the water electrolysis stack group 20, when one water electrolysis stack 62 reaches the end of its life, the other water electrolysis stacks 62 will also reach the end of their life. On the other hand, if water electrolysis stacks 62 with different degrees of deterioration are combined, when one water electrolysis stack 62 reaches the end of its life, the other water electrolysis stacks 62 will not have reached the end of their life, and the amount of heat generated will be smaller. Therefore, as shown in Fig. 5 , the amount of heat generated by the water electrolysis stack group 20 when it is time to replace a water electrolysis stack 62 is smaller when water electrolysis stacks 62 with different degrees of deterioration are combined than when water electrolysis stacks 62 with different degrees of deterioration are not combined.

[0056] Incidentally, in the water electrolysis stack group 20, the control device 32 uses the cooling device 22 to cool the heat generated by the water electrolysis stacks 62. However, as described above, the cooling capacity required of the cooling device 22 differs between during normal operation and when the water electrolysis stacks 62 are replaced. More specifically, the cooling capacity of the cooling device 22 needs to be greater during the replacement of the water electrolysis stacks 62 than during normal operation.

[0057] However, the cooling capacity required when replacing the water electrolysis stack 62 may be too high during normal operation of the water electrolysis stack group 20. For this reason, it is necessary to control the cooling capacity of the cooling device 22 between the normal operation of the water electrolysis stack group 20 and the replacement of the water electrolysis stack 62.

[0058] 5 , the difference in the amount of heat generated by the water electrolysis stack group 20 between the normal operation period and the replacement period of the water electrolysis stack 62 is smaller when the water electrolysis stacks 62 with different degrees of deterioration are combined than when the water electrolysis stacks 62 with different degrees of deterioration are not combined. In other words, when the water electrolysis stack group 20 is combined with the water electrolysis stacks 62 with different degrees of deterioration, the heat control width of the water electrolysis stack group 20 is smaller than when the water electrolysis stack group 20 is not combined with the water electrolysis stacks 62 with different degrees of deterioration.

[0059] As a result, the water electrolysis method according to this embodiment can narrow the fluctuation range of the control range of heat generated from the water electrolysis stack group 20 during the water electrolysis process, compared to a case in which the water electrolysis stack groups 20 are combined so that the levels of deterioration of the water electrolysis stacks 62 included in the water electrolysis stack group 20 are all the same. In other words, this water electrolysis method facilitates heat control of the water electrolysis stack group 20.

[0060] The water electrolysis method of this embodiment uses a plurality of water electrolysis stack groups 20, and the water electrolysis stacks 62 included in different water electrolysis stack groups 20 are replaced with each other to form the water electrolysis stack groups 20. The degree of deterioration of each of the plurality of water electrolysis stack groups 20 is set to fall within a predetermined range. This facilitates control of heat generated from each water electrolysis stack group 20 in a water electrolysis process using a plurality of water electrolysis stack groups 20.

[0061] The above describes an embodiment of the present disclosure with reference to the accompanying drawings. However, it is clear that a person with ordinary knowledge in the field of technology to which the present disclosure pertains can conceive of various modifications or applications within the scope of the technical ideas set forth in the claims, and it is understood that these also naturally fall within the technical scope of the present disclosure. [Explanation of symbols]

[0062] 10 Water electrolysis equipment 20 Water electrolysis stack group 20A First Water Electrolysis Stack Group 20B Second water electrolysis stack group 20C Third water electrolysis stack group 22 Cooling device 24 cabinets 28 Temperature Sensor 32 Control device 40 Control Unit 41 CPU 42 RAM 43 ROM 44 Bus 45 I / O 46 Programs 50 Temperature control unit 56 Communications Department 62 Water electrolysis stack 64 Deteriorated water electrolysis stack 66 Further deterioration of the water electrolysis stack 68 Water electrolysis stack that has reached the end of its life 70 Pure water supply section 72 Power supply 74 Oxygen supply unit 76 Hydrogen Supply Unit 78 Pure water supply line 80 Hydrogen Delivery Line 82 Water and oxygen delivery line

Claims

[Claim 1] configuring a water electrolysis stack group by combining a plurality of water electrolysis stacks having different degrees of deterioration and a cooling device that cools the plurality of water electrolysis stacks; obtaining hydrogen using water electrolysis equipment including the water electrolysis stack group; Equipped with a plurality of the water electrolysis stack groups are used in the water electrolysis facility; In configuring the water electrolysis stack groups, water electrolysis stacks included in different water electrolysis stack groups are replaced with each other to keep the degree of deterioration of each water electrolysis stack group within a predetermined range. Water electrolysis method.

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