Water electrolysis system comprising plurality of modularized water electrolysis stacks, and operating method thereof

Abstract

According to one aspect of the present invention, a water electrolysis system comprising a plurality of modularized water electrolysis stacks is provided, the system comprising: a plurality of water electrolysis stacks; and a stack management unit which determines a stack to be operated from among the plurality of water electrolysis stacks, with reference to load power corresponding to the plurality of water electrolysis stacks and the maximum operating power of each of the plurality of water electrolysis stacks, wherein an operating priority for the plurality of water electrolysis stacks is determined on the basis of a monitoring result of the operating voltage of each of the plurality of water electrolysis stacks.

Description

Electrolysis system comprising a plurality of modularized electrolysis stacks and method for operating the same

[0001] The present invention relates to a water electrolysis system including a plurality of modularized water electrolysis stacks and a method for operating the same.

[0002] Water electrolysis is a method of producing hydrogen, utilizing water electrolysis to extract hydrogen. It is a core technology for the hydrogen economy, producing hydrogen using renewable energy sources, and is being applied in hydrogen energy storage and conversion systems.

[0003] Alkaline electrolysis is one of the oldest and most commercially available electrolysis methods. When a low voltage is applied to the electrolysis stack, hydrogen or oxygen gas can pass through the internal membrane. This can generate heat and increase the risk of explosion, posing a safety risk.

[0004] Figure 1 is a diagram showing the relationship between the operating power of the electrolysis stack and the concentration of gas mixture (specifically, mixture of hydrogen gas and oxygen gas) in a conventional alkaline electrolysis system (10) composed of a single stack.

[0005] Referring to Fig. 1, when the operating power of the electrolysis stack is reduced to less than 20% of the maximum operating power, it becomes difficult for the mixed concentrations of hydrogen and oxygen gases to maintain safety conditions (e.g., legal safety conditions). Specifically, when the operating power of the electrolysis stack is reduced to less than 20% of the maximum operating power, the concentration of oxygen gas in the hydrogen gas exceeds 3% or the concentration of hydrogen gas in the oxygen gas exceeds 2%, and the mixed gas of hydrogen and oxygen gas easily reaches the flammability limit, thereby posing a risk of explosion. Therefore, it is technically not easy to reduce the operating power of the electrolysis stack to less than 20% of the maximum operating power.

[0006] <Prior Art Literature>

[0007] <Patent Document>

[0008] (Patent Document 1) Patent Registration No. 10-2526673 (April 24, 2023)

[0009] The purpose of the present invention is to solve all of the problems of the above-mentioned prior art.

[0010] In addition, another object of the present invention is to enable a water electrolysis system to operate stably even in a situation where the operating power (or load power) is low by individually controlling a plurality of modularized water electrolysis stacks (specifically, individually controlling each water electrolysis stack in a module composed of a plurality of water electrolysis stacks according to the load power).

[0011] In addition, another object of the present invention is to improve the operation quality by assigning an operation priority to each of a plurality of modularized electrolysis stacks and determining an operation target stack corresponding to the load power according to the operation priority.

[0012] In addition, another object of the present invention is to provide high-purity hydrogen by minimizing the concentration of hydrogen gas and oxygen gas mixture.

[0013] A representative configuration of the present invention to achieve the above purpose is as follows.

[0014] According to one aspect of the present invention, there is provided a water electrolysis system including a plurality of modularized electrolysis stacks, the system including a stack management unit that determines an operation target stack among the plurality of electrolysis stacks by referring to the load power corresponding to the plurality of electrolysis stacks and the maximum operation power of each of the plurality of electrolysis stacks, and an operation priority for the plurality of electrolysis stacks is determined based on a result of monitoring the operation voltage of each of the plurality of electrolysis stacks.

[0015] In addition, according to another aspect of the present invention, a method for controlling a water electrolysis system including a plurality of modularized water electrolysis stacks is provided, comprising the steps of: determining an operation target stack among the plurality of water electrolysis stacks by referring to a load power corresponding to the plurality of modularized water electrolysis stacks and a maximum operation power of each of the plurality of water electrolysis stacks; and supplying power corresponding to the load power to the operation target stack, wherein an operation priority for the plurality of water electrolysis stacks is determined based on a result of monitoring an operation voltage of each of the plurality of water electrolysis stacks.

[0016] In addition, another electrolysis system or its operating method according to the technical idea of ​​the present invention is further provided.

[0017] According to the present invention, by individually controlling a plurality of modular electrolysis stacks (specifically, individually controlling each electrolysis stack in a module composed of a plurality of electrolysis stacks according to the load power), the electrolysis system can operate stably even in a situation where the operating power (or load power) is low.

[0018] In addition, according to the present invention, operation priority is given to each of a plurality of modularized electrolysis stacks, and the operation target stack corresponding to the load power is determined according to the operation priority, thereby improving the operation quality.

[0019] In addition, according to the present invention, it is possible to provide high-purity hydrogen by minimizing the mixing concentration of hydrogen gas and oxygen gas.

[0020] Figure 1 is a diagram showing the relationship between the operating power of the electrolysis stack and the gas mixing concentration in a conventional alkaline electrolysis system composed of a single stack.

[0021] FIG. 2 is a drawing exemplarily showing the relationship between the operating power of a water electrolysis stack and the gas mixing concentration in a water electrolysis system including a plurality of modularized water electrolysis stacks according to one embodiment of the present invention.

[0022] FIG. 3 and FIG. 4 are drawings exemplarily showing a process in which a plurality of modularized electrolysis stacks are individually controlled according to one embodiment of the present invention.

[0023] The following detailed description of the present invention refers to the accompanying drawings, which illustrate specific embodiments in which the present invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the present invention. It should be understood that the various embodiments of the present invention, while different from each other, are not necessarily mutually exclusive. For example, specific shapes, structures, and characteristics described herein may be modified and implemented from one embodiment to another without departing from the spirit and scope of the present invention. Furthermore, it should be understood that the positions or arrangements of individual components within each embodiment may also be modified without departing from the spirit and scope of the present invention. Accordingly, the following detailed description is not to be taken in a limiting sense, and the scope of the present invention is to be construed to encompass the scope of the claims and all equivalents thereof. Like reference numerals in the drawings represent the same or similar elements throughout the several aspects.

[0024] Hereinafter, various preferred embodiments of the present invention will be described in detail with reference to the attached drawings so that a person having ordinary skill in the art to which the present invention pertains can easily practice the present invention.

[0025] Composition of the electrolysis system

[0026] FIG. 2 is a diagram exemplarily showing the relationship between the operating power of a water electrolysis stack and the concentration of gas mixture (specifically, mixture of hydrogen gas and oxygen gas) in a water electrolysis system (100) including a plurality of modularized water electrolysis stacks according to one embodiment of the present invention. FIG. 3 and FIG. 4 are diagrams exemplarily showing a process in which a plurality of modularized water electrolysis stacks (110) are individually controlled according to one embodiment of the present invention.

[0027] Referring to FIGS. 2 to 4, a water electrolysis system (100) according to one embodiment of the present invention may be configured to include a plurality of modularized water electrolysis stacks (110) and a stack management unit (120).

[0028] First, a plurality of modularized electrolysis stacks (110) according to one embodiment of the present invention can perform a function of producing hydrogen by electrolyzing supplied water. Here, electrolysis may be performed by at least one of alkaline electrolysis (ALK), cation exchange membrane electrolysis (PEMWE), anion exchange membrane electrolysis (AEMWE), and solid oxide electrolysis (SOECs), and preferably, it may be an alkaline electrolysis (ALK) method that electrolyzes water using an alkaline electrolyte. An example of a reaction occurring at an anode and a cathode of an alkaline electrolysis method is as follows.

[0029] [Reaction 1; Anode] 4OH - → H2O + O2+ 4e -

[0030] [Reaction 2; Cathode] 4H2O + 4e - → 2H2+ 4OH -

[0031] However, it should be noted that the electrolysis method according to the present invention is not necessarily limited to those listed above, and may be modified in various ways within the scope of achieving the purpose of the present invention.

[0032] In addition, a plurality of modularized electrolysis stacks (110) according to one embodiment of the present invention may be formed by modularizing (or grouping) a plurality of electrolysis stacks into one (or more) modules. Specifically, one module may be configured to include a plurality of electrolysis stacks, and as the power (or power source) supplied to each of the plurality of electrolysis stacks is controlled, one module may implement the functions of 1 to N electrolysis stacks (wherein N is the number of electrolysis stacks included in one module). Meanwhile, at least some of the plurality of electrolysis stacks within one module may have the same maximum operating power.

[0033] For example, referring to FIGS. 3 and 4, the modularized plurality of electrolysis stacks (110) may be modularized so that the first electrolysis stack (111) and the second electrolysis stack (112) operate (i.e., produce hydrogen) in response to the first electrolysis stack (111) and the second electrolysis stack (112) being determined as operation target stacks among the plurality of electrolysis stacks, and the first electrolysis stack (111), the second electrolysis stack (112) and the tenth electrolysis stack (113) may be modularized so that the first electrolysis stack (111), the second electrolysis stack (112) and the tenth electrolysis stack (113) operate in response to the first electrolysis stack (111), the second electrolysis stack (112) and the tenth electrolysis stack (113) being determined as operation target stacks among the plurality of electrolysis stacks. The modularized plurality of electrolysis stacks (110) as described above do not require consideration of the risk of explosion as long as the operating power of each electrolysis stack individually satisfies the safety conditions. For example, the minimum driving power of a single stack is P min Assuming that, for a modularized multiple electrolysis stack with the same maximum operating power as a single stack, the minimum operating power is P min / N (where N is the number of electrolysis stacks included in the module, and it is assumed that the maximum operating power is the same for all), which allows the minimum operating power to be lowered.

[0034] More specifically, if 10 electrolysis stacks having a maximum operating power of 10 kW are modularized into one module, the maximum operating power of the module can be 100 kW. Here, assuming that the standard for the minimum operating power that satisfies the safety condition is 20% of the maximum operating power, if the above 100 kW is configured as a single stack, the minimum operating power is 20 kW, but in the case of a plurality of modularized electrolysis stacks (specifically, modules) according to an embodiment of the present invention, the minimum operating power becomes 2 kW.

[0035] Next, the stack management unit (120) according to one embodiment of the present invention may determine an operation target stack among the plurality of electrolysis stacks (110) by referring to the load power corresponding to (or required for) the plurality of modularized electrolysis stacks (110) and the maximum operation power of each of the plurality of electrolysis stacks (110), and may perform a function of supplying power (or power) corresponding to the load power to the operation target stack.

[0036] Specifically, the stack management unit (120) can determine the number of stacks to be operated by referring to the load power corresponding to the plurality of electrolysis stacks (110) and the maximum operating power of each of the plurality of electrolysis stacks (110). In addition, the stack management unit (120) can determine the operating priority for the plurality of electrolysis stacks (110) based on the result of monitoring the quality index of each of the plurality of electrolysis stacks (110), and can determine the electrolysis stack corresponding to the number of stacks to be operated among the plurality of electrolysis stacks (110) as the stack to be operated based on the operating priority. Here, the quality index according to the present invention may include the operating voltage of the electrolysis stack. Specifically, the operating voltage of each of the plurality of electrolysis stacks (110) may be a voltage monitored while the plurality of electrolysis stacks (110) are in operation (specifically, each electrolysis stack is in operation), and may be, for example, an average of voltages measured over a predetermined period of time for the plurality of electrolysis stacks (110) in operation or a voltage measured at a specific point in time.

[0037] For example, the load power corresponding to a plurality of modularized electrolysis stacks (110) is P [kW] (P ≥ P min ; P minIf the minimum operating power of the electrolysis stack (110) among the plurality of electrolysis stacks (110) is M [kW] (for example, assuming that the maximum operating power of the plurality of electrolysis stacks (110) is the same), and the maximum operating power of each of the plurality of electrolysis stacks (110) is M [kW] (for example, assuming that the maximum operating power of all of the plurality of electrolysis stacks (110) is the same), the stack management unit (120) can determine the number of stacks to be operated based on the equation [(P - 1) / M] + 1 (wherein, [ ] denotes a floor function). Meanwhile, the method for determining the number of stacks to be operated according to an embodiment of the present invention is not necessarily limited to those listed above, and a lookup table (or database) corresponding to the load power (or a predetermined section regarding the load power) may be generated within a range that can achieve the purpose of the present invention, and the number of stacks to be operated may be determined by referring to the lookup table (or database).

[0038] In addition, the stack management unit (120) may determine the size of the voltage (specifically, the operating voltage of the stack) specified based on the same current at the same power as the quality index of the stack, and may determine the priority so that a stack with a lower quality index of the stack (i.e., the size of the operating voltage of the stack) is determined as the stack to be operated with priority. Specifically, the stack management unit (120) may determine the priority so that the first electrolysis stack is determined as the stack to be operated with priority over the second electrolysis stack in response to the fact that the monitored operating voltage of the second electrolysis stack is higher than the monitored operating voltage of the first electrolysis stack. More specifically, referring to FIG. 4, it may be assumed that ten electrolysis stacks (110) are modularized into one module, the load power corresponding to the ten modularized electrolysis stacks (110) is 14 kW, and the maximum operating power of the ten electrolysis stacks (110) is 10 kW. First, the stack management unit (120) can determine the number of stacks to be driven as 2 (e.g., [(14 - 1) / 10] + 1) by referring to the load power. Then, the stack management unit (120) can determine the second electrolysis stack (112) with the highest priority (i.e., the stack to be driven first; first priority) among the ten electrolysis stacks (110) and the tenth electrolysis stack (113) with the next highest priority (i.e., second priority) as the stacks to be driven.

[0039] In addition, the stack management unit (120) can determine the power (or power source) to be supplied to the target stack by referring to the maximum operating power of the target stack and the operating priority of the target stack (or multiple electrolysis stacks).

[0040] For example, the stack management unit (120) may determine to supply power (or power) corresponding to the maximum operating power of each operating stack to the remaining operating stacks except for the operating stack with the lowest priority among the operating stacks (or the highest quality index (or operating voltage) among the operating stacks), and to supply the remaining power excluding the power supplied above from the load power to the operating stack with the lowest priority among the operating stacks.

[0041] In addition, the stack management unit (120) according to one embodiment of the present invention may further refer to the minimum driving power of the driving target stack with the lowest priority among the driving target stacks to determine the power (or power source) to be supplied to the driving target stack.

[0042] For example, it can be assumed that the operating target stacks include a first electrolysis stack, a second electrolysis stack, and a third electrolysis stack, and that the operating priorities of the first electrolysis stack, the second electrolysis stack, and the third electrolysis stack decrease in order (i.e., the operating priority of the first electrolysis stack is the highest, and the operating priority of the third electrolysis stack is the lowest), and that the maximum operating power and minimum operating power of the first electrolysis stack, the second electrolysis stack, and the third electrolysis stack are 10 kW and 2 kW, respectively, and the load power corresponding to the first electrolysis stack, the second electrolysis stack, and the third electrolysis stack is 21 kW. In this case, the stack management unit (120) can adjust (specifically, reduce) the power (or power) to be supplied to the first electrolysis stack and the second electrolysis stack (i.e., the remaining operating stacks excluding the operating stack with the lowest priority among the operating stacks) so that operating power (or power) greater than the minimum operating power can be supplied to the third electrolysis stack by referring to the minimum operating power of 2 kW of the third electrolysis stack with the lowest priority. More specifically, the stack management unit (120) can determine that the power to be supplied to the first electrolysis stack is 10 kW, the power to be supplied to the second electrolysis stack is 9 kW, and the power to be supplied to the third electrolysis stack is 2 kW, or the power to be supplied to the first electrolysis stack is 9 kW, the power to be supplied to the second electrolysis stack is 10 kW, and the power to be supplied to the third electrolysis stack is 2 kW.

[0043] Meanwhile, if the maximum operating power of the stacks to be driven is the same as above, the stack management unit (120) compares the result of performing a predetermined calculation based on the load power and the maximum operating power (specifically, the result of calculating (load power mod maximum operating power)) with the minimum operating power of the electrolysis stack with the lowest priority among the stacks to be driven, and if the result of the above calculation is smaller than the minimum operating power, the power (or power) to be supplied to the remaining stacks to be driven, excluding the stack with the lowest priority among the stacks to be driven, is adjusted to decrease by the difference between the result of the above calculation and the minimum operating power, and the power to be supplied to the stack to be driven with the lowest priority is adjusted to increase by the above difference. More specifically, the stack management unit (120) calculates that the result of modulating the load power of 21 kW and the maximum operating power of 10 kW is less than the minimum operating power of 2 kW of the third electrolysis stack, which is the operating stack with the lowest priority among the operating stacks, and therefore adjusts the power (or power) to be supplied to the first electrolysis stack or the second electrolysis stack, which are the operating stacks other than the third electrolysis stack, to be reduced by 1 kW, which is the difference between the above-calculated result and the above-mentioned minimum operating power, from the maximum operating power, and adjusts the power (or power) to be supplied to the third electrolysis stack to be increased by the above-mentioned difference of 1 kW. For example, the stack management unit (120) may determine that the power to be supplied to the first electrolysis stack is 10 kW, the power to be supplied to the second electrolysis stack is 9 kW, and the power to be supplied to the third electrolysis stack is 2 kW, or may determine that the power to be supplied to the first electrolysis stack is 9 kW, the power to be supplied to the second electrolysis stack is 10 kW, and the power to be supplied to the third electrolysis stack is 2 kW.

[0044] Meanwhile, a stack management unit (120) according to one embodiment of the present invention may include a controller (e.g., including a processor) and a power conversion system (PCS), and the functions of the stack management unit (120) described above may be performed by the controller and the power conversion system.

[0045] For example, the controller of the stack management unit (120) may monitor the quality index of each of the plurality of electrolysis stacks (110), determine the operation priority for the plurality of electrolysis stacks (110) based on the result, determine an operation target stack among the plurality of electrolysis stacks (110), and perform a function of determining power to be supplied to the operation target stack. In addition, the power conversion device of the stack management unit (120) may perform a function of supplying corresponding power (or power) to the operation target stack and cutting off power (or power) supplied to a stack that is not the operation target (i.e., a non-operation target stack).

[0046] <Example 1>

[0047] Referring to FIG. 3, it can be assumed that in a water electrolysis system (100) according to one embodiment of the present invention, 10 water electrolysis stacks are modularized into one module, and the maximum operating power of each of the 10 water electrolysis stacks is 10 kW.

[0048] First, according to one embodiment of the present invention, information can be obtained that the load power corresponding to ten modularized electrolysis stacks (110) is 100 kW. Furthermore, based on the results of monitoring the operating voltage of each of the ten electrolysis stacks, the operating priorities for the ten electrolysis stacks can be pre-determined. Specifically, the operating voltage of the first electrolysis stack (111) is 95.8 V, the operating voltage of the second electrolysis stack (112) is 45.8 V, the operating voltage of the third electrolysis stack is 60.7 V, the operating voltage of the fourth electrolysis stack is 52.2 V, the operating voltage of the fifth electrolysis stack is 50.1 V, the operating voltage of the sixth electrolysis stack is 52.7 V, the operating voltage of the seventh electrolysis stack is 46.5 V, the operating voltage of the eighth electrolysis stack is 48.2 V, the operating voltage of the ninth electrolysis stack is 64.5 V, and the operating voltage of the tenth electrolysis stack is 46.2 V, and the second electrolysis stack (112), the tenth electrolysis stack (113), the seventh electrolysis stack, and the eighth electrolysis stack are monitored so that the stacks with lower operating voltages are given priority for operation. The priority may be determined in the following order: the electrolysis stack, the fifth electrolysis stack, the sixth electrolysis stack, the fourth electrolysis stack, the third electrolysis stack, the ninth electrolysis stack, and the first electrolysis stack (111).

[0049] Next, based on the load power corresponding to 10 modularized electrolysis stacks of 100 kW and the maximum operating power of 10 electrolysis stacks of 10 kW according to one embodiment of the present invention, the number of stacks to be operated can be determined as 10 (for example, 10 based on the calculation result of [(100 - 1) / 10] + 1).

[0050] Next, according to one embodiment of the present invention, the power to be supplied to the driving target stack can be determined based on the maximum driving power of the driving target stack and the driving priority of the driving target stack.

[0051] For example, the power to be supplied to the remaining operating target stacks, excluding the first electrolysis stack having the lowest priority among the operating target stacks, is determined to be 10 kW, which is the power corresponding to the maximum operating power of each operating target stack, and the power to be supplied to the first electrolysis stack having the lowest priority among the operating target stacks is determined to be 10 kW, which is the remaining power excluding the power supplied above from 100 kW.

[0052] Next, according to one embodiment of the present invention, power corresponding to a load power of 100 kW can be supplied in 10 kW each to the first to tenth electrolysis stacks.

[0053] <Example 2>

[0054] Referring to FIG. 4, it can be assumed that in a water electrolysis system (100) according to one embodiment of the present invention, 10 water electrolysis stacks are modularized into one module, and the maximum operating power of each of the 10 water electrolysis stacks is 10 kW.

[0055] First, according to one embodiment of the present invention, information that the load power corresponding to 10 modularized electrolysis stacks (110) is 14 kW can be obtained. In addition, the operation priorities for the 10 electrolysis stacks can be pre-determined based on the results of monitoring the operation voltage of each of the 10 electrolysis stacks. Specifically, the priorities can be determined in the order of the second electrolysis stack (112), the tenth electrolysis stack (113), the seventh electrolysis stack, the eighth electrolysis stack, the fifth electrolysis stack, the sixth electrolysis stack, the fourth electrolysis stack, the third electrolysis stack, the ninth electrolysis stack, and the first electrolysis stack (111).

[0056] Next, according to one embodiment of the present invention, the number of stacks to be operated may be determined as 2 based on 14 kW, which is the load power corresponding to 10 electrolysis stacks, and 10 kW, which is the maximum operating power of 10 electrolysis stacks (for example, determined as 2 based on a lookup table regarding the number of stacks corresponding to each load power section).

[0057] Next, according to one embodiment of the present invention, the power to be supplied to the driving target stack can be determined based on the maximum driving power of the driving target stack and the driving priority of the driving target stack.

[0058] For example, the power to be supplied to the first electrolysis stack, which is the remaining operating stack except for the 10th electrolysis stack with the lowest priority among the operating stacks, is determined to be 10 kW, which is the power corresponding to the maximum operating power, and the power to be supplied to the 10th electrolysis stack with the lowest priority among the operating stacks is determined to be 4 kW, which is the remaining power excluding the power to be supplied above from 14 kW.

[0059] Next, according to one embodiment of the present invention, power corresponding to a load power of 14 kW can be distributed and supplied to the second electrolysis stack and the tenth electrolysis stack (specifically, 10 kW is supplied to the second electrolysis stack and 4 kW is supplied to the tenth electrolysis stack).

[0060] Although the present invention has been described above with specific details such as specific components and limited examples and drawings, these are provided only to help a more general understanding of the present invention, and the present invention is not limited to the above examples, and those with ordinary knowledge in the technical field to which the present invention pertains can make various modifications and changes based on this description.

[0061] Therefore, the idea of ​​the present invention should not be limited to the embodiments described above, and not only the scope of the patent claims described below but also all scopes equivalent to or equivalently modified from the scope of the patent claims are considered to fall within the scope of the idea of ​​the present invention.

[0062] <Explanation of symbols>

[0063] 10: Conventional alkaline water electrolysis system consisting of a single stack

[0064] 100: A water electrolysis system comprising multiple modularized water electrolysis stacks.

[0065] 110: Modular multiple electrolysis stacks

[0066] 120: Stack Management

Claims

1. A water electrolysis system comprising a plurality of modularized water electrolysis stacks, Modularized multiple electrolysis stacks, and A stack management unit is included that determines an operation target stack among the plurality of electrolysis stacks by referring to the load power corresponding to the plurality of electrolysis stacks and the maximum operating power of each of the plurality of electrolysis stacks, The operating priority for the plurality of electrolysis stacks is determined based on the results of monitoring the operating voltage of each of the plurality of electrolysis stacks. Electrolysis system.

2. In paragraph 1, The above multiple electrolysis stacks have the same maximum operating power. Electrolysis system.

3. In paragraph 1, The above plurality of electrolysis stacks include a first electrolysis stack and a second electrolysis stack, In response to the fact that the operating voltage of the second electrolysis stack is greater than the operating voltage of the first electrolysis stack, the first electrolysis stack is determined as the operating target stack with priority over the second electrolysis stack. Electrolysis system.

4. In paragraph 2, The stack management unit determines the number of stacks to be operated by referring to the load power corresponding to the plurality of electrolysis stacks and the maximum operating power of each of the plurality of electrolysis stacks, Referring to the above driving priority, the driving target stack corresponding to the above number among the plurality of electrolysis stacks is determined. Electrolysis system.

5. In paragraph 4, Determine the power to be supplied to the driving target stack by referring to the driving priority of the driving target stack and the minimum driving power of the driving target stack. Electrolysis system.

6. A method for controlling a water electrolysis system including a plurality of modularized water electrolysis stacks, A step of determining an operation target stack among the plurality of electrolysis stacks by referring to the load power corresponding to the plurality of modularized electrolysis stacks and the maximum operating power of each of the plurality of electrolysis stacks, and A step of supplying power corresponding to the above load power to the driving target stack is included, The operating priority for the plurality of electrolysis stacks is determined based on the results of monitoring the operating voltage of each of the plurality of electrolysis stacks. Method for controlling a water electrolysis system.

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