fuel cell ship

Abstract

To avoid a situation where a fuel cell ship is stopped on the sea during navigation even when a failure of fuel cells occurs or the fuel cell reaches a device life during navigation of the fuel cell ship.SOLUTION: A fuel cell ship includes: a propulsion device for generating a propulsion force in a hull by power; a power supply part for supplying the power to the propulsion device; and a degradation rate control part for adjusting a degradation rate. The power supply part has a plurality of fuel cells for generating power by an electrochemical reaction of a fuel, and at least one storage cell.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a fuel cell ship. [Background technology]

[0002] BACKGROUND ART Conventionally, a fuel cell ship has been proposed in which fuel gas (for example, hydrogen gas) is supplied from a fuel tank to a fuel cell, and a propulsion device is driven by the electricity generated by the fuel cell (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-92815 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the configuration of Patent Document 1, the fuel cell ship is equipped with only one fuel cell, so if a malfunction occurs in the fuel cell ship while the ship is sailing, or if the fuel cell reaches the end of its equipment life, there is a risk that the ship will be unable to continue sailing and will have to stop at sea.

[0005] The present invention has been made to solve the above-mentioned problems, and its purpose is to provide a fuel cell ship that can avoid the situation where the fuel cell ship has to stop at sea while sailing if a fuel cell malfunctions during sailing or if the fuel cell reaches the end of its equipment life. [Means for solving the problem]

[0006] A fuel cell ship according to one aspect of the present invention is a fuel cell ship comprising a propulsion device that generates propulsive force for the hull using electricity, and a power supply unit that supplies the electricity to the propulsion device, wherein the power supply unit has a plurality of fuel cells that generate electricity through an electrochemical reaction of fuel, and at least one storage battery. [Effects of the Invention]

[0007] According to the above configuration, even if a fuel cell malfunction occurs while the fuel cell ship is sailing, or if the fuel cell reaches the end of its equipment life, it is possible to avoid the fuel cell ship coming to a halt at sea while sailing. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is an explanatory diagram showing a schematic configuration of a fuel cell ship according to an embodiment of the present invention; [Figure 2] FIG. 2 is a block diagram schematically illustrating the configuration of a main part of the fuel cell ship. [Figure 3] FIG. 4 is a block diagram schematically showing another configuration of the fuel cell ship. [Figure 4] 10 is a time chart schematically showing a replacement plan for each fuel cell as an operation plan for the fuel cell ship. [Figure 5] 1 is a graph showing the relationship between the operation time and the cell voltage of the fuel cell when the fuel cell is operated at a low load to suppress degradation and when the fuel cell is operated at a high load to promote degradation. [Figure 6] 10 is a graph showing the relationship between the power generation output per fuel cell and the rate of deterioration. [Figure 7] 10 is a flowchart showing a flow of adjusting the deterioration rate of the fuel cell. [Figure 8] 10 is a graph showing an example of the change over time in the power load of the fuel cell ship. [Figure 9] 10 is a graph showing a schematic diagram of the change in the deterioration rate with respect to the operating time of the fuel cell. [Figure 10] 10 is a flowchart showing a flow of adjusting another deterioration rate of the fuel cell. [Figure 11] FIG. 2 is an explanatory diagram schematically illustrating the internal structure of the fuel cell ship. DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment of the present invention will be described below with reference to the drawings. In this specification, directions are defined as follows: First, the direction from the stern of a fuel cell ship toward the bow is defined as "forward," and the direction from the bow toward the stern is defined as "rearward." The lateral direction perpendicular to the fore-aft direction is defined as the left-right direction. In this case, when the fuel cell ship is moving forward, the left side as seen from the operator is defined as "left," and the right side is defined as "right." Furthermore, the upstream side of the direction of gravity perpendicular to the fore-aft and left-right directions is defined as "up," and the downstream side is defined as "down."

[0010] [1. Overview of fuel cell ship] First, the basic configuration of the fuel cell ship SH according to this embodiment will be described with reference to Figure 1. Figure 1 is an explanatory diagram showing the general configuration of the fuel cell ship SH. The fuel cell ship SH comprises a hull 1 and a cabin 2. The cabin 2 is located on the top surface of the hull 1.

[0011] The fuel cell ship SH further includes a fuel cell system 3, a fuel gas storage unit 4, a battery system 5, a propulsion device 6, a plurality of peripheral devices 11, and a control device 12. In Fig. 1, control signal or high-voltage power supply lines are indicated by solid lines, and control signal or low-voltage power supply lines are indicated by dashed lines.

[0012] The fuel cell system 3 functions as a main power source. The fuel cell system 3 consumes fuel gas to generate electric power (specifically, DC power). The fuel gas is a combustible gas. Typically, the fuel gas is hydrogen gas. The fuel cell system 3 supplies the generated electric power to the propulsion device 6 and peripheral devices 11. The fuel cell system 3 can also supply electric power to the storage battery system 5 to charge the storage battery system 5.

[0013] The fuel gas storage unit 4 is a fuel storage unit that stores fuel gas to be supplied to the fuel cell system 3. The fuel gas is supplied from the fuel gas storage unit 4 to the fuel cell system 3 via a fuel gas supply pipe 32 (see FIG. 11) described later.

[0014] The storage battery system 5 functions as an auxiliary power source that supplies stored power (specifically, DC power) to the propulsion device 6 and peripheral devices 11. In this way, the storage battery system 5 functions as an auxiliary power source, making it possible to compensate for a shortage of power supply from the fuel cell system 3 to the propulsion device 6 and the like. The storage battery system 5 may also convert the power to an appropriate voltage and supply it to the control device 12.

[0015] The propulsion device 6 is driven by electric power supplied from at least one of the fuel cell system 3 and the storage battery system 5, and generates a propulsive force for the hull 1. In other words, the fuel cell ship SH is equipped with a propulsion device 6 that generates a propulsive force for the hull 1 using electric power.

[0016] The propulsion device 6 includes a power converter 6a, a propulsion motor 6b, and a propeller 6c. The power converter 6a converts the power supplied from the fuel cell system 3 into power conforming to the specifications of the propulsion motor 6b. For example, the power converter 6a converts DC power into AC power. In this case, the power converter 6a includes, for example, an inverter. The propulsion motor 6b is driven by the power (for example, AC power) supplied from the power converter 6a. When the propulsion motor 6b is driven, the rotational force of the propulsion motor 6b is transmitted to the propeller 6c. As a result, the propeller 6c rotates, generating a propulsive force for the hull 1. Note that a marine gear may be provided between the propulsion motor 6b and the propeller 6c.

[0017] The peripheral devices 11 include, for example, compressors, electromagnetic valves, pumps, etc. The peripheral devices 11 also include electrical devices such as lighting equipment and air conditioners, but the types of the peripheral devices 11 are not particularly limited.

[0018] The control device 12 controls the fuel cell system 3, the fuel gas storage unit 4, the battery system 5, the propulsion device 6, and a plurality of peripheral devices 11. The control device 12 is configured, for example, with one or more computers. The computer is, for example, a programmable logic controller (PLC), but may also be an electronic control unit (ECU). The control device 12 is supplied with power from a battery (for example, a lead battery) not shown, or from the battery system 5 via a device that converts the power to an appropriate voltage.

[0019] The control device 12 includes a control unit 12a and a memory unit 12b. The control unit 12a includes a processor such as a CPU (Central Processing Unit). The memory unit 12b includes a storage device and stores data and computer programs. Specifically, the memory unit 12b includes a main storage device such as a semiconductor memory and an auxiliary storage device such as a semiconductor memory, a solid-state drive, and / or a hard disk drive. The memory unit 12b may include removable media. The memory unit 12b corresponds to an example of a non-transitory computer-readable storage medium.

[0020] The processor of the control unit 12a controls the fuel cell system 3, the fuel gas storage unit 4, the battery system 5, the propulsion device 6, and multiple peripheral devices 11 by executing computer programs stored in the storage device of the memory unit 12b.

[0021] [2. Main components of fuel cell ship] Figure 2 is a block diagram showing a schematic configuration of the main parts of the fuel cell ship SH of this embodiment. In the figure, the dashed lines indicate the fuel gas supply paths, and the solid lines indicate the electric power supply paths or the supply paths of control signals output by the control unit 12a. The fuel cell ship SH is equipped with an electric power supply unit 100. The electric power supply unit 100 supplies electric power to the propulsion device 6 described above.

[0022] The power supply unit 100 includes a fuel cell system 3. The fuel cell system 3 includes a plurality of fuel cells 31. The fuel cells 31 generate electric power (specifically, DC power) through an electrochemical reaction between a fuel gas and an oxidant gas. The fuel gas is an example of a fuel supplied to the fuel cells 31 from a fuel tank 41 (described later) of the fuel gas storage unit 4. The oxidant gas is air, and the oxidant is oxygen. In other words, the power supply unit 100 has a plurality of fuel cells 31 that generate electric power through an electrochemical reaction of fuel.

[0023] The fuel cell 31 is a fuel cell stack composed of multiple stacked cells. For example, each cell of the fuel cell 31 has a solid polymer electrolyte membrane, an anode, a cathode, and a pair of separators. The anode and cathode sandwich the solid polymer electrolyte membrane. The anode is the negative electrode (fuel electrode). The anode includes an anode catalyst layer and a gas diffusion layer. The cathode is the positive electrode (air electrode). The cathode includes a cathode catalyst layer and a gas diffusion layer. The anode, solid polymer electrolyte membrane, and cathode form a membrane electrode assembly (MEA). A pair of separators sandwich the membrane electrode assembly. Each separator has multiple grooves. Each groove in one separator forms a flow path for fuel gas. Each groove in the other separator forms a flow path for oxidant gas.

[0024] In the above-described configuration of the fuel cell 31, hydrogen contained in the fuel gas is decomposed into hydrogen ions and electrons by a catalyst on the anode side. The hydrogen ions pass through the solid polymer electrolyte membrane and move to the cathode side. Meanwhile, the electrons move through an external circuit to the cathode side. This generates current (electricity is generated). On the cathode side, oxygen contained in the oxidant gas combines with the electrons that have flowed through the external circuit and the hydrogen ions that have passed through the solid polymer electrolyte membrane to produce water. The produced water is discharged overboard via the discharge pipe 31a (see FIG. 11).

[0025] The fuel cell 31 supplies the generated power to the propulsion device 6 and the peripheral devices 11. Note that the fuel cell 31 may also supply the generated power to the propulsion device 6 and the peripheral devices 11 indirectly via a circuit such as a DC / DC converter.

[0026] The power supply unit 100 further includes a storage battery system 5. The storage battery system 5 includes a storage battery 51 that stores power. The storage battery 51 is, for example, a lithium secondary battery, but may also be a nickel-cadmium storage battery, a nickel-metal hydride storage battery, or the like. The number of storage batteries 51 is not particularly limited, and may be one or more. In other words, the power supply unit 100 has at least one storage battery 51.

[0027] The capacity of the storage battery 51 can be set as appropriate. When there are multiple storage batteries 51, the storage batteries 51 may be connected in series or in parallel. The storage batteries 51 supply stored power to the propulsion device 6 and peripheral devices 11.

[0028] As described above, since the power supply unit 100 has a plurality of fuel cells 31 and at least one storage battery 51, even if one of the plurality of fuel cells 31 fails for some reason or reaches the end of its equipment life while the fuel cell ship SH is sailing, power generation can be continued using the remaining fuel cells 31, and the power generated by that fuel cell 31 can be supplied to the propulsion device 6 to operate the propulsion device 6. Furthermore, even if power generation in all of the fuel cells 31 stops for some reason or reaches the end of their equipment life and they are stopped, power stored in at least one storage battery 51 can be supplied to the propulsion device 6 to operate the propulsion device 6. In other words, even if at least one of the fuel cells 31 fails or reaches the end of its equipment life while the fuel cell ship SH is sailing, it is possible to avoid a situation in which the fuel cell ship SH stops at sea while sailing.

[0029] The fuel gas storage section 4 of the fuel cell ship SH has a fuel tank 41. The fuel tank 41 stores fuel gas as fuel to be supplied to the fuel cells 31. In this embodiment, a plurality of fuel tanks 41 are provided. That is, the fuel cell ship SH is equipped with a plurality of fuel tanks 41 that store fuel. Each of the plurality of fuel cells 31 described above is connected to at least one fuel tank 41 via a fuel gas supply pipe 32 (see FIG. 11). Then, fuel gas is supplied to each fuel cell 31 from at least one fuel tank 41.

[0030] 2, the fuel cell ship SH is provided with, for example, five fuel tanks 41. For ease of explanation, the fuel tanks 41 are also referred to as individual tanks 41a to 41e. In other words, the multiple fuel tanks 41 include multiple individual tanks 41a to 41e that store fuel gas.

[0031] In this embodiment, the plurality of fuel tanks 41 particularly includes individual tanks 41 a and 41 b. The individual tanks 41 a and 41 b are connected to two or more of the same fuel cells 31 (for example, fuel cells 31 a and 31 b in FIG. 2 ) among the plurality of fuel cells 31.

[0032] With this configuration, even if one of the multiple fuel cells 31 (for example, fuel cell 31a) fails for some reason or reaches the end of its life while the fuel cell ship SH is sailing, fuel gas can be supplied from the individual tanks 41a and 41b to the remaining fuel cell 31 (for example, fuel cell 31b) to continue power generation, allowing the fuel cell ship SH to continue sailing. Therefore, in this case, the fuel gas stored in each of the individual tanks 41a and 41b can be used effectively (it can be used up to drive the other fuel cells 31b).

[0033] Of the multiple fuel tanks 41, individual tanks 41c and 41d are each connected to the same fuel cell 31c and supply fuel gas to the same fuel cell 31c, while individual tank 41e is connected to one fuel cell 31d and supplies fuel gas to only that one fuel cell 31d.

[0034] FIG. 3 is a block diagram showing a schematic diagram of another configuration of the fuel cell ship SH. For convenience, the fuel gas storage unit 4 shown in FIG. 2 is omitted from the drawing. As shown in the drawing, when a propulsion unit 6 and a power supply unit 100 are considered to be one set of propulsion power units 60, the fuel cell ship SH may have two sets of propulsion power units 60, or, although not shown, may have three or more sets. In other words, the fuel cell ship SH may have multiple sets of propulsion units 6 and power supply units 100. When it is necessary to particularly distinguish between the propulsion power units 60, the propulsion power units 60 will be referred to as propulsion power unit 60a and propulsion power unit 60b. The configuration of the power supply units 100 in the propulsion power units 60a and 60b is the same as that in FIG. 2.

[0035] With this configuration, even if a failure occurs for some reason in the fuel cell 31 or propulsion unit 6 in one of the sets (for example, the propulsion power unit 60a) while the fuel cell ship SH is sailing, the other set (for example, the propulsion power unit 60b) will continue to operate, allowing the fuel cell ship SH to continue sailing. As a result, it is possible to avoid the fuel cell ship SH coming to a halt while sailing.

[0036] [3. Operational plan for fuel cell ships] Next, the operation plan for the fuel cell ship SH will be explained. As an example, let us assume that the fuel cell ship SH is equipped with six fuel cells 31, and that the fuel cells 31 equipped at the start of operation of the fuel cell ship SH are fuel cells A0, B0, C0, D0, E0, and F0.

[0037] FIG. 4 is a time chart that schematically illustrates a replacement plan for each fuel cell 31 as part of the operation plan for the fuel cell ship SH. Replacement of each fuel cell 31 is typically carried out when the fuel cell ship SH is docked for maintenance. Medium-sized or large ships generally dock about once every one to three years. When a fuel cell 31 reaches the end of its life while the ship is sailing, docking solely to replace the fuel cell 31 affects the ship's operation plan and significantly reduces economic efficiency. For this reason, it is desirable to match the timing of replacement due to the end of the life of the fuel cell 31 with the timing (maintenance period) of the fuel cell ship SH, which is based on a pre-established operation plan.

[0038] In this embodiment, as shown in FIG. 4, two or three fuel cells 31 are replaced at predetermined docking times every two years, while all fuel cells are kept in an operable state at all times. For example, fuel cell A0 is replaced with fuel cell A1 two years after the start of operation, and then replaced with fuel cell A2 four years later (six years after the start of operation). Similarly, fuel cell B0 is replaced with fuel cell B1 two years after the start of operation, and then replaced with fuel cell B2 four years later. Fuel cell C0 is replaced with fuel cell C1 four years after the start of operation, and then replaced with fuel cell C2 four years later. Similarly, fuel cell D0 is replaced with fuel cell D1 four years after the start of operation, and then replaced with fuel cell D2 four years later. Fuel cell E0 is replaced with fuel cell E1 four years after the start of operation. Fuel cell F0 is replaced with fuel cell F1 six years after the start of operation.

[0039] Note that "high load" in the diagram indicates operation that accelerates the degradation of the fuel cell 31, that is, operation (high load operation) in which the rate at which degradation of the fuel cell 31 progresses relative to the operating time is relatively fast. On the other hand, "low load" indicates operation that suppresses the degradation of the fuel cell 31, that is, operation (low load operation) in which the rate at which degradation of the fuel cell 31 progresses relative to the operating time is relatively slow. Degradation of the fuel cell 31 refers to, for example, degradation of the catalyst (e.g., platinum) contained in the electrodes (anode and cathode) of the fuel cell 31.

[0040] The operating pattern (high load operation / low load operation) of each fuel cell 31 is set in advance based on the specifications of the fuel cell 31 and the operation plan of the fuel cell ship SH. The operating pattern setting is updated according to the actual deterioration state of the fuel cells 31, which is confirmed at each maintenance. Note that the operation pattern of the fuel cell ship SH may be machine learned, and the control unit 12a may automatically determine the optimal replacement plan based on the actual deterioration state of the fuel cells 31.

[0041] [4. Fuel cell deterioration rate] In this embodiment, the degree of deterioration of the fuel cell 31 is also referred to as the "deterioration rate." The deterioration rate corresponds to the cell voltage when a predetermined current per unit area is passed through the cells constituting the stack of fuel cells 31, and takes a value between 0 and 100%. A deterioration rate of 0% corresponds to the cell voltage in the initial state of the fuel cell 31 (a state without deterioration). A deterioration rate of 100% corresponds to the cell voltage when the fuel cell 31 has deteriorated and needs to be replaced.

[0042] 5 is a diagram showing the relationship between the operation time T (hours) and the cell voltage Vc (V) of the fuel cell 31. The cell voltage Vc on the vertical axis is calculated based on a current of 0.6 A per unit area of ​​the cell of the fuel cell stack (i.e., 0.6 A / cm2). 2 ) is passed through the fuel cell 31. Here, Vc = V0 = 0.75 V in the initial state of the fuel cell 31 (operating time 0 hours). In other words, a fuel cell 31 with a cell voltage Vc of V0 indicates that the degradation rate is 0%. Note that the above current and voltage values ​​are merely examples and are not limited to the above values. Note that in FIG. 5, the solid line graph indicates the change in cell voltage when low-load operation is performed to suppress degradation, and the dashed line graph indicates the change in cell voltage when high-load operation is performed to promote degradation.

[0043] The longer the operating time of the fuel cell 31, the more the fuel cell 31 deteriorates. As the deterioration of the fuel cell 31 progresses, the cell voltage V decreases, as shown in FIG. 5. Here, the state of the fuel cell 31 when the cell voltage V reaches a value (V = VL = 0.67V) that is 10% lower than the initial state is considered to be a 100% deterioration rate. As mentioned above, it is desirable that the timing at which V = VL is reached coincides with the maintenance date and time. Note that the amount of decrease in cell voltage and the cell voltage that result in a 100% deterioration rate can be set appropriately depending on the material and surface area of ​​the electrodes (catalyst) of the fuel cell 31, and are not limited to the above-mentioned "10%" and "0.67V."

[0044] [5. Adjusting the fuel cell deterioration rate (low output side)] 6 shows the relationship between the power generation output P per fuel cell and the rate of deterioration Dv (% / h). The rate of deterioration Dv indicates the amount of change (decrease) in the rate of deterioration of the fuel cell 31 per unit time.

[0045] The low-load operation mentioned above refers to causing the fuel cell 31 to generate power in a region where the rate of deterioration Dv of the fuel cell 31 is low in the curve of Figure 6. For example, operation in which the power output P of the fuel cell 31 is between 20 kW and 110 kW is low-load operation because the rate of deterioration Dv of the fuel cell 31 is below a predetermined value Dth. Note that when the fuel cell ship SH comes to a complete stop and the power output P of the fuel cell 31 is 0 (kW), the rate of deterioration Dv of the fuel cell 31 reaches its lowest point, zero.

[0046] On the other hand, high-load operation refers to causing the fuel cell 31 to generate power in a region where the rate of deterioration Dv of the fuel cell 31 is high in the curve of Figure 6. For example, operation in which the power output P of the fuel cell 31 is less than 20 kW or operation in which the power output P is greater than 110 kW is high-load operation because the rate of deterioration Dv of the fuel cell 31 is greater than the predetermined value Dth.

[0047] Also, for example, even if the fuel cell ship SH completely stops, in order to drive peripheral devices 11 such as lighting equipment, when the power generation of the fuel cell 31 continues within the range of 0 < P ≤ 20 kW, from FIG. 6, the progress rate Dv of the deterioration of the fuel cell 31 exceeds a predetermined value Dth. In this state, the fuel cell 31 is under high-load operation, and the deterioration of the fuel cell 31 is accelerated. Furthermore, frequently repeating the startup and stop of the fuel cell 31 results in continuous operation of the fuel cell 31 with a power generation output P less than 20 kW, leading to high-load operation that accelerates the deterioration of the fuel cell 31.

[0048] Here, the power generation output P of the fuel cell 31 when the progress rate Dv of the deterioration of the fuel cell 31 reaches the predetermined value Dth is defined as Pdeg here. From FIG. 6, it can also be said that the power generation output Pdeg is the lower limit value (for example, 20 kW) of the range (20 ≤ P ≤ 110 kW) of the power generation output P of the fuel cell 31 in which the progress rate Dv of the deterioration of the fuel cell 31 remains below the predetermined value (predetermined value Dth).

[0049] Here, as shown in FIG. 6, when Pdeg = 20 kW, in the fuel cell ship SH equipped with six fuel cells 31, if the power consumed in the ship (power demand) is 120 kW or less, which is 20 kW × 6, when each fuel cell 31 is operated so that the power of 120 kW or less is evenly divided among the six fuel cells, deterioration is accelerated in all the fuel cells 31. That is, even the fuel cells 31 operated under low-load operation become under high-load operation. In this case, there is a possibility that the replacement reference time when replacement of the fuel cells 31 operated under low-load operation is required may be earlier than the initial replacement scheduled time (maintenance time).

[0050] Furthermore, depending on the length of time the fuel cell ship SH is at anchor, stopping power generation may suppress deterioration or may accelerate deterioration. For example, if the fuel cell ship SH is at anchor for a short time, power generation by the fuel cell 31 will resume shortly after power generation is stopped. As described above, repeatedly turning the fuel cell 31 on and off accelerates deterioration of the fuel cell 31 because the fuel cell 31 continues to operate so that the power output P is less than 20 kW. On the other hand, if the fuel cell ship SH is at anchor for a long time, the period during which power generation by the fuel cell 31 is stopped will be longer, and the time during which the rate of deterioration of the fuel cell 31 reaches zero will be longer, resulting in suppression of deterioration of the fuel cell 31.

[0051] Therefore, in this embodiment, when the power generation output P of one fuel cell 31 falls below Pdeg, power generation of at least one of the fuel cells 31 is stopped to adjust the rate of deterioration Dv and deterioration rate of the fuel cells 31. This accelerates or suppresses the deterioration of the fuel cells 31, making it possible to bring the estimated replacement date of the fuel cell 31 closer to or coincide with the scheduled replacement date.

[0052] The control unit 12a of this embodiment described above functions as a deterioration rate control unit that adjusts the deterioration rate of each of the multiple fuel cells 31. That is, the fuel cell ship SH of this embodiment is equipped with the control unit 12a as a deterioration rate control unit that adjusts the deterioration rate that indicates the degree of deterioration of each of the multiple fuel cells 31.

[0053] The following is a specific description of the procedure for adjusting the deterioration rate of the fuel cell 31 by the control unit 12a. Figure 7 is a flowchart showing the flow of adjusting the deterioration rate of the fuel cell 31.

[0054] First, the control unit 12a determines whether the power load W (kW) consumed by the fuel cell ship SH is equal to or less than a first threshold value Wth1 (S1). Here, the first threshold value Wth1 is a value determined according to the above-mentioned power generation output Pdeg (kW) of one fuel cell and the number Nfc (units) of fuel cells 31 installed, and specifically, Wth1 = Pdeg × Nfc.

[0055] Figure 8 is a graph showing the change in the power load W of the fuel cell ship SH over time. The power load W of the fuel cell ship SH is the total power load consumed by the fuel cell ship SH, including the power consumed by the peripheral devices 11. As shown in the figure, at time t1 when W≦Wth1, the control unit 12a begins adjusting the deterioration rate of the fuel cell 31. Note that if W>Wth1 at S1, the control unit 12a waits without adjusting the deterioration rate.

[0056] If W≦Wth1 in S1, the control unit 12a then determines whether the fuel cell ship SH is at anchor (S2). For example, if it is predicted that the power required on board will be less than a predetermined value for a certain period of time (for example, 48 hours) based on the operation plan of the fuel cell ship SH, the control unit 12a can determine that the fuel cell ship SH is at anchor. On the other hand, if the above prediction cannot be made, the control unit 12a can determine that the fuel cell ship SH is not at anchor.

[0057] If it is determined in S2 that the fuel cell ship SH is at anchor, the control unit 12a determines whether the predicted anchoring time Ts is equal to or greater than a predetermined time T1 (for example, 48 hours) (S3). The predicted anchoring time Ts may be a time set in advance by the ship operator operating the input unit, or may be a time obtained by machine learning based on an operation plan for the fuel cell ship SH.

[0058] In S3, when Ts≧T1, the control unit 12a stops the power generation of the fuel cell 31 for which deterioration is to be suppressed, that is, the fuel cell 31 operated under low load operation (S4). In this case, as described above, since the power generation stop period of the fuel cell 31 is long, the deterioration of the fuel cell 31 operated under low load operation is suppressed. On the other hand, since the fuel cell 31 operated under high load operation continues to generate power, its deterioration progresses, and as a result, the deterioration is accelerated. In S2, when the fuel cell ship SH is not at anchor, the process also proceeds to S4. As a result, the deterioration of the fuel cell 31 operated under low load operation is suppressed, and the deterioration of the fuel cell 31 operated under high load operation is accelerated. When there are a plurality of fuel cells 31 operated under high load operation, the control unit 12a evenly divides the power load W in S1 by the number of the fuel cells 31, and causes the fuel cells 31 to output the shared power (S5).

[0059] On the other hand, in S3, when Ts<T1, the control unit 12a stops the power generation of the fuel cell 31 for which deterioration is to be accelerated, that is, the fuel cell 31 operated under high load operation (S6). In this case, since the fuel cell 31 operated under high load operation resumes power generation in a short period after the power generation stop (as planned), as a result, the deterioration is accelerated. On the other hand, although the power generation of the fuel cell 31 operated under low load operation continues, since the power generation and stop in a short period are not repeated, the acceleration of deterioration does not occur, and the deterioration is relatively suppressed. When there are a plurality of fuel cells 31 operated under low load operation, the control unit 12a evenly divides the power load W in S1 by the number of the fuel cells 31, and causes the fuel cells 31 to output the shared power (S7).

[0060] FIG. 9 schematically shows the change in the deterioration rate D with respect to the operation time T of the fuel cell 31. The solid line graph in the figure shows the change in the deterioration rate D of the fuel cell 31 operated under low load operation for which deterioration is suppressed, and the broken line graph shows the change in the deterioration rate D of the fuel cell 31 operated under high load operation for which deterioration is accelerated. Also, the deterioration rate D suitable for replacement of the fuel cell 31 is represented by Dex. In the present embodiment, Dex = 100%.

[0061] By stopping the power generation of a specific fuel cell 31 as described above, the control unit 12a can adjust the rate of deterioration Dv of the fuel cell 31 and thereby adjust the deterioration rate D. This makes it possible to bring the estimated replacement time Tc1 of a fuel cell 31 operating under high load closer to or coincide with the scheduled replacement time Tm1, which is the timing of the docking, and to replace the fuel cell 31 operating under high load during maintenance at the scheduled replacement time Tm1. Similarly, it makes it possible to bring the estimated replacement time Tc2 of a fuel cell 31 operating under low load closer to or coincide with the scheduled replacement time Tm2, ​​which is the timing of the docking, and to replace the fuel cell 31 operating under low load during maintenance at the scheduled replacement time Tm2.

[0062] In other words, when the time when the deterioration rate D of each fuel cell 31 reaches a deterioration rate Dex suitable for replacement due to deterioration of each fuel cell 31 is defined as the estimated replacement time Tc, and the preset replacement time for each fuel cell 31 is defined as the scheduled replacement time Tm, the control unit 12a, which functions as a deterioration rate control unit, adjusts the deterioration rate D of at least one fuel cell 31 (within a predetermined period (e.g., 10 years) from the start of operation) so that the estimated replacement time Tc for each fuel cell 31 approaches or coincides with the scheduled replacement time Tm (in the above example, so that Tc1 approaches or coincides with Tm1, and so that Tc2 approaches or coincides with Tm2). This makes it possible to perform replacement work for each fuel cell 31 when the fuel cell ship SH enters dock (for maintenance), enabling efficient operation of the fuel cell ship SH. It also makes it possible to avoid a situation in which each fuel cell 31 deteriorates and reaches the end of its life while the fuel cell ship SH is sailing, making it necessary to replace each fuel cell 31 while the ship is sailing.

[0063] Furthermore, the control unit 12a adjusts the deterioration rate of the fuel cells 31 when the power load W consumed by the fuel cell ship SH becomes equal to or less than a first threshold value Wth1, which is determined based on the lower limit value Pdeg of the power output P of the fuel cells 31 at which the rate of deterioration Dv of the fuel cells 31 becomes equal to or less than a predetermined value Dth, and the number Nfc of fuel cells 31 on board (S1 to S5). Moreover, the control unit 12a varies the way in which the deterioration rate is adjusted depending on the expected time (expected berthing time Ts) that the state of being equal to or less than the first threshold value Wth1 will continue (S3, S4, S6).

[0064] If each fuel cell 31 is caused to generate power at an equal output when the onboard power load W falls below the first threshold Wth1, deterioration of all fuel cells 31 will be accelerated. By adjusting the deterioration rate when W≦Wth1 and varying the method of adjusting the deterioration rate depending on the predicted berthing time Ts, it is possible to suppress deterioration of fuel cells 31 operated under low load and bring their estimated replacement dates Tc2 closer to or coincide with the scheduled replacement date Tm2. Furthermore, it is possible to accelerate deterioration of fuel cells 31 operated under high load and bring their estimated replacement dates Tc1 closer to or coincide with the scheduled replacement date Tm1.

[0065] The multiple fuel cells 31 also include fuel cells 31 that are operated at high loads and fuel cells 31 that are operated at low loads based on the operation plan for the fuel cell ship SH. The control unit 12a then determines whether the fuel cell ship SH is in a state where it is expected to be anchored based on the operation plan (S2), and if anchoring is not expected, stops power generation by the fuel cells 31 that are operated at low loads (S4). In this case, deterioration of the fuel cells 31 that are operated at low loads is suppressed, making it possible to reduce the occurrence of a situation in which the estimated replacement time Tc2 and the planned replacement time Tm2 for the fuel cells differ significantly.

[0066] Further, when the predicted parking time Ts of the fuel cell ship SH is equal to or longer than a predetermined time T1 determined according to the operation plan, the control unit 12a stops the power generation of the fuel cell 31 operated under low load operation (S3, S4). By stopping power generation for a long time, deterioration of the fuel cell 31 operated under low load operation is suppressed. Thereby, it is possible to reduce a situation where the replacement reference time Tc2 and the planned replacement time Tm2 of the fuel cell 31 deviate greatly.

[0067] Further, the control unit 12a evenly distributes the power load W of the fuel cell ship SH among the number of fuel cells 31 operated under high load operation, and causes each fuel cell 31 operated under high load operation to output the shared power (S5). In this case, deterioration of the plurality of fuel cells 31 operated under high load operation can proceed at the same degree, and the timings at which the respective fuel cells 31 reach the end of their service lives can be aligned. Thereby, the operation of replacing the respective fuel cells 31 together becomes very effective.

[0068] Further, when the predicted parking time Ts of the fuel cell ship SH is less than the predetermined time T1, the control unit 12a stops the power generation of the fuel cell 31 operated under high load operation (S6). Stopping and starting the power generation of the fuel cell 31 in a short period of time rather becomes a factor for accelerating deterioration of the fuel cell 31. When Ts < T1, it is predicted that the fuel cell 31 will be started in a short period of time after the power generation of the fuel cell 31 operated under high load operation stops (after the predicted parking time Ts reaches the predetermined time T1). By accelerating deterioration due to the stop and start of the fuel cell 31 in a short period of time, the replacement reference time Tc1 of the fuel cell 31 operated under high load operation is brought closer to (or made to coincide with) the appropriate planned replacement time Tm1 based on the operation plan, and the replacement work can be performed at an appropriate timing.

[0069] Furthermore, the control unit 12a equally shares the power load W of the fuel cell ship SH among the number of fuel cells 31 operating at low load, and causes each fuel cell 31 operating at low load to output its share of the power (S7). In this case, the deterioration of the multiple fuel cells 31 operating at low load can be caused to progress at the same rate, so that the timing at which each fuel cell 31 reaches the end of its life can be synchronized. This makes it very effective to replace each fuel cell 31 at the same time.

[0070] In addition, if it is determined that the deterioration of the fuel cell 31 operated under high load conditions is progressing more than expected and that it will reach the end of its life earlier than the recommended replacement time Tc1, the fuel cell 31 may be temporarily switched to low load operation to adjust the deterioration rate of the fuel cell 31.

[0071] [6. Adjusting the fuel cell deterioration rate (high-power side)] 6, the rate of deterioration Dv of the fuel cell 31 increases even when the power generation output P of the fuel cell 31 increases. This is because when a large current flows through each cell of the fuel cell 31, the temperature of the fuel cell 31 increases locally even if the fuel cell 31 is cooled by a cooling medium. For this reason, for example, if the fuel cell 31 is operated under low load and is made to output power exceeding the rated output Prated (kW), deterioration will be accelerated despite the desire to suppress it.

[0072] Therefore, in this embodiment, when the power load W of the fuel cell ship SH is large, the control unit 12a, which serves as a deterioration rate control unit, performs the following control to suppress deterioration of the fuel cells 31 operating at low load. This point will be explained below.

[0073] 10 is a flowchart showing the flow of adjusting other deterioration rates of the fuel cell 31. First, the control unit 12a determines whether the power load W consumed by the fuel cell ship SH is equal to or greater than a second threshold value Wth2 (S11). Here, the second threshold value Wth2 is a value determined according to the rated output Prated of one fuel cell and the number Nfc (units) of fuel cells 31 installed, and specifically, Wth2 = Prated × Nfc.

[0074] Note that Prated is, for example, 80 (kW) (see FIG. 6), but is not limited to this value and can be set appropriately depending on the material, surface area, etc. of the electrodes of the fuel cell 31. Note that when the maximum output of the fuel cell 31 is Pmax (kW), Prated <Pmaxである。

[0075] If W≧Wth2 in S11, the control unit 12a adjusts the deterioration rate of at least one fuel cell 31 (S12). For example, the control unit 12a sets the power generation output Preq (kW) of the fuel cell 31 for which deterioration is desired to be suppressed, i.e., the fuel cell 31 operated in low-load operation, to a value equal to or less than the rated output Prated (S12). In other words, the fuel cell 31 operated in low-load operation is operated at a power generation output Preq that satisfies Preq≦Prated. As a result, the power generation output of the fuel cell 31 operated in low-load operation is suppressed to Preq, thereby suppressing deterioration of the fuel cell 31 and reducing its deterioration rate. At this time, the control unit 12a may set the power generation output of the fuel cell 31 operated in high-load operation to a value equal to or greater than the rated output Prated. In this case, the deterioration rate of the fuel cell 31 operated in high-load operation can be increased, thereby accelerating its deterioration.

[0076] In this way, the control unit 12a adjusts the deterioration rate of (at least one) fuel cell 31 when the power load W consumed by the fuel cell ship SH is equal to or greater than the second threshold value Wth2, which is determined according to the rated output Prated of the fuel cell 31 and the number Nfc of fuel cells 31 installed. As a result, even when the power load W of the fuel cell ship SH is large, the deterioration rate of fuel cells 31 operated at low load can be reduced to suppress deterioration. Therefore, it is possible to avoid a situation in which deterioration is accelerated for fuel cells 31 operated at low load, despite the desire to suppress deterioration. On the other hand, for fuel cells 31 operated at high load, the deterioration rate can be increased as described above to promote deterioration.

[0077] Furthermore, the control unit 12a sets the power generation output Preq of the fuel cell 31 that is being operated at low load among the multiple fuel cells 31, i.e., the fuel cell 31 that is the target for suppressing deterioration, to a value equal to or less than the rated output Prated (S12). This makes it possible to reliably suppress deterioration of the fuel cell 31 that is being operated at low load even when the power load W of the fuel cell ship SH is large.

[0078] [7. Internal structure of fuel cell ships] Next, the internal structure of the fuel cell ship SH described above will be described in detail. Figure 11 is an explanatory diagram that schematically shows the internal structure of the fuel cell ship SH. In Figure 11, the air flow is indicated by dashed arrows. In Figure 11, each component is illustrated with the right side of the drawing as the bow side and the left side of the drawing as the stern side, but the positions of each component are not limited to those shown in Figure 11 as long as the connection relationships between each component are maintained.

[0079] The fuel cell ship SH comprises an engine room 13 and a fuel room 14. The engine room 13 and the fuel room 14 are located below the deck 1a of the hull 1. In other words, the engine room 13 and the fuel room 14 are located between the deck 1a and the bottom plate 1b of the hull 1. The bottom plate 1b is located between the deck 1a and the ship bottom 1c (see Figure 1).

[0080] The engine room 13 is located on the bow side of the fuel room 14. Bulkheads W1, W2, and W3 are located below the deck 1a in this order from the bow side to the stern side. The engine room 13 is separated from other spaces by bulkheads W1 and W2. The fuel room 14 is separated from other spaces by bulkheads W2 and W3. The bulkheads W1 to W3 are made of, for example, fiber reinforced plastics (FRP), but may also be made of steel plates.

[0081] (7-1. Configuration of fuel cell system) The fuel cell system 3 of the fuel cell ship SH is located in the engine room 13. The fuel cell system 3 has the above-mentioned fuel cell 31, a fuel gas supply pipe 32, and a fuel cell-side shutoff valve 33. The fuel cell-side shutoff valve 33 is an example of peripheral equipment 11 (see FIG. 1).

[0082] The fuel gas supply pipe 32 is a fuel supply pipe for supplying fuel gas stored in a fuel tank 41 (to be described later) of the fuel gas storage unit 4 to the anode of the fuel cell 31.

[0083] The fuel cell-side shutoff valve 33 is an example of a shutoff valve SV that opens or closes the flow path of the fuel gas supply pipe 32. The opening and closing of the fuel cell-side shutoff valve 33 is controlled by the control unit 12a (see FIG. 1). Specifically, the fuel cell-side shutoff valve 33 switches between supplying and stopping the supply of fuel gas from the fuel tank 41 to the fuel cell 31 based on the control of the control unit 12a. Only one fuel cell-side shutoff valve 33 is provided on the fuel gas supply pipe 32 in the fuel cell compartment 30, which will be described later, but two or more may be provided.

[0084] The fuel cell ship SH further includes a fuel cell compartment 30. The fuel cell compartment 30 is a container that houses fuel cells 31, and is arranged in the engine room 13. Note that, for convenience, only one fuel cell compartment 30 is shown in Figure 11, but because the fuel cell ship SH of this embodiment has multiple fuel cells 31 as described above (see Figure 2, etc.), multiple fuel cell compartments 30 are also provided corresponding to each fuel cell 31.

[0085] The fuel cell compartment 30 has a hollow shape. For example, the fuel cell compartment 30 has a hollow, approximately rectangular parallelepiped shape. In this case, the outer walls constituting the fuel cell compartment 30 include, for example, a top wall 30a, a bottom wall 30b, a front wall (not shown), a back wall (not shown), a side wall 30c, and a side wall 30d. However, the top, bottom, front, back, and side surfaces of the fuel cell compartment 30 can be arbitrarily determined. Furthermore, the shape of the fuel cell compartment 30 is not particularly limited as long as it has a space large enough to accommodate the fuel cell 31. The fuel cell compartment 30 can also be considered as a container, chamber, or box that accommodates the fuel cell 31. The material of the outer wall of the fuel cell compartment 30 is, for example, FRP, but may also be a steel plate.

[0086] A battery compartment air inlet 30e is provided in the side wall 30d of the fuel cell compartment 30. The battery compartment air inlet 30e is connected to a battery compartment air inlet pipe 35, which will be described later. The battery compartment air inlet 30e may be provided in an outer wall of the fuel cell compartment 30 other than the side wall 30d.

[0087] Meanwhile, a battery compartment exhaust port 30f is provided in the side wall 30c of the fuel cell compartment 30. The battery compartment exhaust port 30f is in communication with a duct compartment 90, which will be described later. Note that the battery compartment exhaust port 30f may be provided in an outer wall of the fuel cell compartment 30 other than the side wall 30c.

[0088] The fuel cell compartment 30 has an internal space that is sealed except for a cell compartment air inlet 30e and a cell compartment air outlet 30f.

[0089] The fuel cell compartment 30 accommodates a portion of the fuel gas supply pipe 32 and a fuel cell-side shutoff valve 33. The fuel cell compartment 30 also accommodates a cell compartment internal gas detector 34a and a cell compartment internal fire detector 34b.

[0090] The cell compartment internal gas detector 34a is a fuel gas detector disposed inside the fuel cell compartment 30. For example, when the fuel gas is hydrogen gas, the cell compartment internal gas detector 34a is configured with a hydrogen gas detection sensor.

[0091] The battery compartment internal gas detector 34a is disposed on the inner surface of the top wall 30a located at the top of the fuel cell compartment 30. Hydrogen gas, which serves as fuel gas, is lighter than air and rises. Therefore, by disposing the battery compartment internal gas detector 34a on the top wall 30a of the fuel cell compartment 30, even if fuel gas leaks within the fuel cell compartment 30, the leaked fuel gas can be reliably detected by the battery compartment internal gas detector 34a. The battery compartment internal gas detector 34a may be located at the most downstream side of the flow path through which the fuel gas flows when the fuel gas leaks within the fuel cell compartment 30.

[0092] When the battery compartment internal gas detector 34a detects fuel gas in the fuel cell compartment 30, the detection signal is sent from the battery compartment internal gas detector 34a to the control unit 12a. This causes the control unit 12a to control the fuel cell side shutoff valve 33 provided in the fuel gas supply pipe 32 to stop the supply of fuel gas from the fuel tank 41 to the fuel cell 31.

[0093] The battery compartment internal fire detector 34b is a fire detector disposed inside the fuel cell compartment 30. The battery compartment internal fire detector 34b includes, for example, one or more sensors selected from a smoke sensor that detects smoke, a heat sensor that detects heat, and a flame sensor that detects flames. The battery compartment internal fire detector 34b may be configured as a thermocouple-type fire detector.

[0094] The battery compartment internal fire detector 34b is disposed on the inner surface of the top wall 30a located at the top of the fuel cell compartment 30. In the unlikely event that a fire breaks out inside the fuel cell compartment 30, the battery compartment internal fire detector 34b detects the fire and outputs a detection signal indicating the occurrence of a fire to the control unit 12a (see FIG. 2). In this case, the control unit 12a controls the fuel cell-side shutoff valve 33 to stop the supply of fuel gas from the fuel tank 41 to the fuel cell 31. This minimizes the risk of an explosion in the fuel cell compartment 30 due to ignition of the fuel gas.

[0095] A battery compartment air supply pipe 35 is connected to the fuel cell compartment 30. The battery compartment air supply pipe 35 extends from the battery compartment air supply port 30e of the fuel cell compartment 30 to the deck 1a and is exposed from the upper surface of the deck 1a.

[0096] A battery compartment air supply device 36 and a battery compartment external gas detector 37 are disposed at the end of the battery compartment air supply pipe 35 on the deck 1a side. The battery compartment air supply device 36 and the battery compartment external gas detector 37 are located at the top of the deck 1a.

[0097] The battery compartment air supply device 36 is configured, for example, as an inexpensive non-explosion-proof air supply fan, but may also be configured as an explosion-proof air supply fan. The operation of the battery compartment air supply device 36 is controlled by the control unit 12a. The battery compartment air supply device 36 may be provided with one or more filters (not shown). The filters remove, for example, dust or sea salt particles.

[0098] The battery compartment air supply device 36 supplies air from outside the fuel cell compartment 30 to the inside of the fuel cell compartment 30 via the battery compartment air supply pipe 35 and the battery compartment air supply port 30e. The air inside the fuel cell compartment 30 is discharged to the duct compartment 90 via the battery compartment exhaust port 30f. This ventilates the inside of the fuel cell compartment 30. As a result, it is possible to prevent flammable gas (e.g., fuel gas leaking from the fuel cell 31) from accumulating inside the fuel cell compartment 30.

[0099] The battery compartment external gas detector 37 detects combustible gases (such as hydrogen gas floating around the hull 1) flowing from the outside of the fuel cell compartment 30 into the interior thereof. The battery compartment external gas detector 37 is a combustible gas sensor, such as a hydrogen gas sensor. The battery compartment external gas detector 37 is disposed on the opposite side of the battery compartment air supply device 36 from the battery compartment air supply pipe 35, that is, upstream of the air flow from the outside of the fuel cell compartment 30 to the interior thereof. The battery compartment external gas detector 37 may also be configured as a gas sensor that detects combustible gases other than hydrogen gas. Combustible gases other than hydrogen gas include, for example, methane, ethane, propane, and carbon monoxide.

[0100] The battery compartment external gas detector 37 outputs a detection signal indicating, for example, the concentration of combustible gas to the control unit 12a. Based on the detection signal, the control unit 12a can determine whether the concentration of combustible gas is equal to or greater than a specified value. If the concentration is equal to or greater than the specified value, the control unit 12a controls the fuel cell-side shutoff valve 33 to stop the supply of fuel gas from the fuel tank 41 to the fuel cell 31. The specified value may be determined based on experiments and / or experience.

[0101] The fuel cell ship SH further includes a cooling medium tank 38 and cooling medium piping 39. The cooling medium tank 38 stores a cooling medium for cooling the fuel cells 31. The cooling medium is, for example, an antifreeze liquid with low electrical conductivity. The antifreeze liquid is, for example, a liquid mixture of pure water and ethylene glycol in a predetermined ratio. The cooling medium tank 38 is sealed, but the top may be open.

[0102] The cooling medium piping 39 is a piping for circulating the cooling medium between the fuel cell 31 and a heat exchanger (not shown). A circulation pump (not shown) is also provided midway through the cooling medium piping 39. The circulation pump is driven to supply the cooling medium from the heat exchanger to the fuel cell 31 via the cooling medium piping 39, thereby cooling the fuel cell 31. The cooling medium used to cool the fuel cell 31 is also supplied to the cooling medium tank 38 via the cooling medium piping 39, where volume changes due to temperature changes of the cooling medium are absorbed and the liquid volume of the cooling medium is monitored.

[0103] A cooling tank internal gas detector 38a is provided at an upper portion inside the cooling medium tank 38. The cooling tank internal gas detector 38a is a fuel gas detector that detects fuel gas present in the cooling medium tank 38. The fuel gas present in the cooling medium tank 38 may be, for example, fuel gas that has leaked from the fuel cell 31 and entered the cooling medium tank 38 via the cooling medium piping 39. The detection result of the fuel gas by the cooling tank internal gas detector 38a (for example, information on the concentration of the fuel gas) is sent to the control unit 12a. Based on the detection result by the cooling tank internal gas detector 38a, the control unit 12a can thereby determine whether or not there is a fuel gas leak in the fuel cell 31, and if there is a leak, can perform control to, for example, stop power generation in the fuel cell 31.

[0104] (7-2. Configuration of fuel gas storage section) The fuel gas storage section 4 of the fuel cell ship SH has the above-mentioned fuel tank 41, gas filling pipe 42, and tank-side shutoff valve 43. The tank-side shutoff valve 43 is an example of peripheral equipment 11.

[0105] The fuel tank 41 stores fuel gas as fuel to be supplied to the fuel cell 31. For convenience, only one fuel tank 41 is shown in Figure 11, but the number of fuel tanks 41 is not particularly limited, and there may be multiple fuel tanks 41 (see Figure 2).

[0106] The gas filling pipe 42 is a pipe for refilling the fuel tank 41 with fuel gas or filling it with inert gas. One end of the gas filling pipe 42 is connected to the fuel tank 41. The other end of the gas filling pipe 42 branches into two, which are connected to a fuel gas filling port 82 and an inert gas filling port 84, respectively. The fuel gas filling port 82 and the inert gas filling port 84 are provided in a duct section 90 (particularly the upper duct section 80), which will be described later.

[0107] The inert gas is, for example, nitrogen gas. For example, if fuel gas remains in the fuel tank 41 when the fuel cell ship SH is undergoing maintenance such as inspection or repair in a dock, there is a risk of an explosion if the fuel gas ignites for some reason. Therefore, when performing maintenance on the fuel cell ship SH, the fuel tank 41 is filled with inert gas and the fuel gas is removed from the fuel tank 41. This makes it possible to avoid the risk of explosion.

[0108] In the fuel gas supply pipe 32 described above, the side opposite to the side connected to the fuel cell 31 is connected to the fuel tank 41. In other words, the fuel tank 41 and the fuel cell 31 are connected via the fuel gas supply pipe 32.

[0109] The tank-side shutoff valve 43 is an example of a shutoff valve SV that opens or closes the flow path of the fuel gas supply pipe 32. The opening and closing of the tank-side shutoff valve 43 is controlled by the control unit 12a. Specifically, the tank-side shutoff valve 43 switches between supplying and stopping the supply of fuel gas from the fuel tank 41 to the fuel cell 31 based on the control of the control unit 12a. Only one tank-side shutoff valve 43 is provided on the fuel gas supply pipe 32 in the tank compartment 40, which will be described later, but two or more tank-side shutoff valves 43 may be provided.

[0110] In other words, it can be said that the fuel gas supply pipe 32 connecting the fuel tank 41 and the fuel cell 31 has at least two shutoff valves SV. The at least two shutoff valves SV include the fuel cell-side shutoff valve 33 and the tank-side shutoff valve 43.

[0111] The fuel cell ship SH further includes a tank compartment 40. The tank compartment 40 is a container that houses at least one fuel tank 41. The tank compartment 40 is disposed in the fuel chamber 14. The number of tank compartments 40 is not particularly limited, and may be one or more.

[0112] The tank compartment 40 has a hollow shape. For example, the tank compartment 40 has a hollow, approximately rectangular parallelepiped shape. In this case, the outer walls constituting the tank compartment 40 include, for example, a top wall 40a, a bottom wall 40b, a front wall (not shown), a back wall (not shown), a side wall 40c, and a side wall 40d. However, the top, bottom, front, back, and side surfaces of the tank compartment 40 can be arbitrarily determined. Furthermore, the shape of the tank compartment 40 is not particularly limited as long as it has a space large enough to accommodate at least one fuel tank 41. The tank compartment 40 can also be considered as a container, chamber, or box that accommodates the fuel tank 41. The material of the outer walls of the tank compartment 40 is, for example, FRP, but may also be steel plate.

[0113] A tank compartment air supply port 40e is provided in an opening in the side wall 40c of the tank compartment 40. The tank compartment air supply port 40e is connected to a tank compartment air supply pipe 45, which will be described later. Note that the tank compartment air supply port 40e may be provided in an outer wall of the tank compartment 40 other than the side wall 40c.

[0114] Meanwhile, a tank compartment exhaust port 40f is provided in the top wall 40a of the tank compartment 40. The tank compartment exhaust port 40f is connected to a vent pipe 10. The vent pipe 10 is a pipe for directing air inside the tank compartment 40 to the outside of the ship. Note that the tank compartment exhaust port 40f may be provided in an outer wall of the tank compartment 40 other than the top wall 40a.

[0115] The tank compartment 40 has an internal space that is sealed except for the tank compartment air inlet 40e and the tank compartment air outlet 40f.

[0116] The tank compartment 40 accommodates a portion of the fuel gas supply pipe 32 and a tank-side shutoff valve 43. The tank compartment 40 also accommodates an internal tank compartment gas detector 44a and an internal tank compartment fire detector 44b.

[0117] The tank compartment internal gas detector 44a is a fuel gas detector disposed inside the tank compartment 40. For example, when the fuel gas is hydrogen gas, the tank compartment internal gas detector 44a is configured with a hydrogen gas detection sensor.

[0118] The tank compartment internal gas detector 44a is disposed on the top wall 40a located at the top of the tank compartment 40, near the tank compartment vent port 40f or inside the tank compartment vent port 40f. In the unlikely event that fuel gas leaks from the fuel tank 41 inside the tank compartment 40, the leaked fuel gas passes through the tank compartment vent port 40f and heads toward the vent pipe 10. In other words, the tank compartment vent port 40f is located at the most downstream side of the flow path through which the fuel gas flows when the fuel gas leaks inside the tank compartment 40. Therefore, by disposing the tank compartment internal gas detector 44a at a position near the tank compartment vent port 40f or inside the tank compartment vent port 40f, no matter where the fuel gas leaks inside the tank compartment 40, the leaked fuel gas can be reliably detected by the tank compartment internal gas detector 44a located at the most downstream side of the flow path.

[0119] When the tank compartment internal gas detector 44a detects fuel gas in the tank compartment 40, the detection signal is sent from the tank compartment internal gas detector 44a to the control unit 12a. As a result, the control unit 12a can control the tank-side shutoff valve 43 and the fuel cell-side shutoff valve 33 provided in the fuel gas supply pipe 32 to stop the supply of fuel gas from the fuel tank 41 to the fuel cell 31, and can also release the high-pressure hydrogen remaining inside the pipe by opening the release valve 72.

[0120] The tank compartment internal fire detector 44b is a fire detector disposed inside the tank compartment 40. The tank compartment internal fire detector 44b includes, for example, one or more sensors selected from a smoke sensor that detects smoke, a heat sensor that detects heat, and a flame sensor that detects flame. The tank compartment internal fire detector 44b may be configured as a thermocouple-type fire detector.

[0121] The tank compartment internal fire detector 44b is disposed on the inner surface of the top wall 40a located at the top of the tank compartment 40. In the unlikely event that a fire breaks out inside the tank compartment 40, the tank compartment internal fire detector 44b detects the fire and outputs a detection signal indicating the occurrence of a fire to the control unit 12a. In this case, the control unit 12a controls the tank-side shutoff valve 43 and the fuel cell-side shutoff valve 33 to stop the supply of fuel gas from the fuel tank 41 to the fuel cell 31, and also opens the release valve 72 to release any high-pressure hydrogen remaining inside the piping. This minimizes the risk of an explosion in the tank compartment 40 due to ignition of the fuel gas.

[0122] A tank compartment air supply pipe 45 is connected to the tank compartment 40. The tank compartment air supply pipe 45 extends from the tank compartment air supply port 40e of the tank compartment 40 to the deck 1a and is exposed from the upper surface of the deck 1a.

[0123] A tank compartment air supply device 46 and a tank compartment external gas detector 47 are disposed at the end of the tank compartment air supply pipe 45 on the deck 1a side. The tank compartment air supply device 46 and the tank compartment external gas detector 47 are located at the top of deck 1a.

[0124] The tank compartment air supply device 46 is configured, for example, by an inexpensive non-explosion-proof air supply fan, but may also be configured by an explosion-proof air supply fan. The operation of the tank compartment air supply device 46 is controlled by the control unit 12a. One or more filters (not shown) may be arranged in the tank compartment air supply device 46. The filters remove, for example, dust or sea salt particles.

[0125] The tank compartment air supply device 46 supplies air from outside the tank compartment 40 to the inside of the tank compartment 40 via the tank compartment air supply pipe 45 and the tank compartment air supply port 40e. The air inside the tank compartment 40 is discharged to the vent pipe 10 via the tank compartment exhaust port 40f. This ventilates the inside of the tank compartment 40. As a result, even if fuel gas leaks from the fuel tank 41 inside the tank compartment 40, the accumulation of the fuel gas can be suppressed.

[0126] The tank compartment external gas detector 47 detects flammable gases (such as hydrogen gas floating around the hull 1) flowing from the outside of the tank compartment 40 into the inside. The tank compartment external gas detector 47 is a flammable gas sensor such as a hydrogen gas sensor. The tank compartment external gas detector 47 is disposed on the opposite side of the tank compartment air supply device 46 from the tank compartment air supply pipe 45, that is, upstream of the air flow from the outside of the tank compartment 40 to the inside. The tank compartment external gas detector 47 may be configured as a gas sensor that detects flammable gases other than hydrogen gas.

[0127] The tank compartment external gas detector 47 outputs a detection signal indicating, for example, the concentration of combustible gas to the control unit 12a. Based on the detection signal, the control unit 12a can determine whether the concentration of combustible gas is equal to or greater than a specified value. If the concentration is equal to or greater than the specified value, the control unit 12a controls the tank-side shutoff valve 43 and the fuel cell-side shutoff valve 33 to stop the supply of fuel gas from the fuel tank 41 to the fuel cell 31, and also opens the release valve 72 to release the high-pressure hydrogen remaining in the piping. The specified value may be determined based on experimentation and / or experience.

[0128] (7-3. Duct Section) The fuel cell ship SH further includes a lower duct section 70 and an upper duct section 80. Here, the lower duct section 70 and the upper duct section 80 are collectively referred to as a duct section 90. The duct section 90 is a housing that houses various types of piping. For example, the duct section 90 houses a portion of the fuel gas supply piping 32. The interior of the lower duct section 70 and the interior of the upper duct section 80 are connected via a duct connection section 91. The lower duct section 70 and the upper duct section 80 will be described in detail below.

[0129] 7-3-1. Lower duct section The lower duct section 70 is disposed below the deck 1a. Specifically, the lower duct section 70 is disposed in the engine room 13. Within the engine room 13, the lower duct section 70 is located aft of the fuel cell section 30. In other words, the lower duct section 70 is located below the deck 1a, between the fuel cell section 30 and the tank section 40. The lower duct section 70 accommodates a portion of the fuel gas supply piping 32 and a portion of the gas fill piping 42.

[0130] Here, the "part of the fuel gas supply piping 32" accommodated in the lower duct section 70 refers to the part of the fuel gas supply piping 32 that is located between the fuel cell section 30 and the tank section 40. In addition, the "part of the gas fill piping 42" accommodated in the lower duct section 70 refers to the part of the gas fill piping 42 that is located between the tank section 40 and the upper duct section 80.

[0131] The lower duct section 70 is made of a material such as FRP, but may also be made of steel plate. The lower duct section 70 has a hollow shape. For example, the lower duct section 70 has a hollow, approximately rectangular parallelepiped shape. In this case, the outer walls constituting the lower duct section 70 include, for example, a top wall 70a, a bottom wall 70b, a front wall (not shown), a back wall (not shown), a side wall 70c, and a side wall 70d. However, the top, bottom, front, back, and side surfaces of the lower duct section 70 can be arbitrarily determined. Furthermore, the shape of the lower duct section 70 is not particularly limited as long as it has a space large enough to accommodate a portion of the fuel gas supply pipe 32, etc. The lower duct section 70 can also be considered as a container, chamber, or box that accommodates a portion of the fuel gas supply pipe 32, etc.

[0132] A lower duct section air intake port 70e is provided in a side wall 70d of the lower duct section 70. The lower duct section air intake port 70e is connected to a lower duct section air intake pipe 74, which will be described later. Note that the lower duct section air intake port 70e may be provided in an outer wall of the lower duct section 70 other than the side wall 70d.

[0133] Meanwhile, a lower duct section communication port 70f is provided in the top wall 70a of the lower duct section 70. The lower duct section communication port 70f is in communication with the above-mentioned duct communication portion 91. Note that the lower duct section communication port 70f may be provided in an outer wall of the lower duct section 70 other than the top wall 70a.

[0134] Furthermore, a battery compartment communication port 70g is provided in the side wall 70d of the lower duct section 70. The battery compartment communication port 70g is connected to the battery compartment exhaust port 30f of the fuel cell section 30 described above via a communication pipe 92. As a result, air inside the fuel cell section 30 flows into the lower duct section 70 via the battery compartment exhaust port 30f, the communication pipe 92, and the battery compartment communication port 70g. Note that the battery compartment communication port 70g may be provided in an outer wall of the lower duct section 70 other than the side wall 70d.

[0135] The communicating pipe 92 is configured, for example, as a double pipe consisting of an inner pipe and an outer pipe. The inner pipe is configured, for example, as the fuel gas supply pipe 32. The outer pipe is located radially outside the inner pipe. Gas inside the fuel cell compartment 30 flows from the cell compartment exhaust port 30f, passing between the inner pipe and the outer pipe of the communicating pipe 92, toward the cell compartment communicating port 70g of the lower duct compartment 70.

[0136] The lower duct section 70 has an internal space that is sealed except for the lower duct section air intake port 70e, the lower duct section communication port 70f, and the battery section communication port 70g.

[0137] The lower duct section 70 accommodates a portion of the fuel gas discharge pipe 71. The fuel gas discharge pipe 71 is a pipe that branches off from the fuel gas supply pipe 32 located inside the lower duct section 70. For example, the fuel gas discharge pipe 71 is located between two shutoff valves SV and branches off from the fuel gas supply pipe 32.

[0138] More specifically, the fuel gas discharge pipe 71 branches off from the fuel gas supply pipe 32 between the tank-side shutoff valve 43 in the tank compartment 40 and the fuel cell-side shutoff valve 33 in the fuel cell compartment 30. The fuel gas discharge pipe 71 extends from the inside of the lower duct compartment 70 to the inside of the upper duct compartment 80 via the lower duct compartment communication port 70f and the duct communication section 91, and further communicates with the inside of the vent pipe 10. Therefore, the "part of the fuel gas discharge pipe 71" accommodated in the lower duct compartment 70 refers to the portion of the fuel gas discharge pipe 71 located between the branch point with the fuel gas supply pipe 32 and the upper duct compartment 80.

[0139] The lower duct section 70 further accommodates a release valve 72. The release valve 72 is an on-off valve that is installed in the fuel gas discharge pipe 71 and opens or closes the flow path of the fuel gas discharge pipe 71. The release valve 72 is an example of peripheral equipment 11. The opening and closing of the release valve 72 is controlled by the control unit 11. The release valve 72 may also be installed in the upper duct section 80.

[0140] The lower duct section 70 further houses a lower duct section internal gas detector 73. The lower duct section internal gas detector 73 is a fuel gas detector disposed inside the lower duct section 70. For example, when the fuel gas is hydrogen gas, the lower duct section internal gas detector 73 is configured with a hydrogen gas detection sensor.

[0141] The lower duct section internal gas detector 73 is disposed on the top wall 70a located above the lower duct section 70, near the lower duct section communication port 70f or inside the lower duct section communication port 70f. In the unlikely event that fuel gas leaks from the fuel gas supply pipe 32 inside the lower duct section 70, the leaked fuel gas passes through the lower duct section communication port 70f and heads toward the upper duct section 80. In other words, the lower duct section communication port 70f is located at the most downstream side of the flow path through which the fuel gas flows when fuel gas leaks inside the lower duct section 70. Therefore, by disposing the lower duct section internal gas detector 73 near the lower duct section communication port 70f or inside the lower duct section communication port 70f, regardless of the location of the fuel gas leak within the lower duct section 70, the leaked fuel gas can be reliably detected by the lower duct section internal gas detector 73 located at the most downstream side of the flow path.

[0142] When the lower duct section internal gas detector 73 detects fuel gas in the lower duct 70, the detection signal is sent from the lower duct section internal gas detector 73 to the control unit 12a. As a result, the control unit 12a controls the shutoff valve SV provided in the fuel gas supply pipe 32 to stop the supply of fuel gas from the fuel tank 41 to the fuel cell 31.

[0143] It should be noted that the lower duct section 70 may further house a fire detector for detecting a fire inside the lower duct section 70 .

[0144] A lower duct section air intake pipe 74 is connected to the lower duct section 70. The lower duct section air intake pipe 74 extends from a lower duct section air intake port 70e of the lower duct section 70 to the deck 1a and is exposed from the upper surface of the deck 1a.

[0145] A lower duct section air supply device 75 and a lower duct section external gas detector 76 are disposed at the end of the lower duct section air supply pipe 74 on the deck 1a side. The lower duct section air supply device 75 and the lower duct section external gas detector 76 are located at the upper part of deck 1a.

[0146] The lower duct section air intake device 75 is configured, for example, by an inexpensive non-explosion-proof air intake fan, but may also be configured by an explosion-proof air intake fan. The driving of the lower duct section air intake device 75 is controlled by the control unit 12a. The lower duct section air intake device 75 may be provided with one or more filters (not shown). The filters remove, for example, dust or sea salt particles.

[0147] The lower duct section air supply device 75 supplies air from outside the lower duct section 70 (duct section 90) to the interior of the lower duct section 70 via the lower duct section air supply pipe 74 and the lower duct section air supply port 70e. The air inside the lower duct section 70 is discharged to the upper duct section 80 via the lower duct section communication port 70f. This ventilates the interior of the lower duct section 70. As a result, even if fuel gas leaks from the fuel gas supply pipe 32 inside the lower duct section 70, the accumulation of the fuel gas can be suppressed.

[0148] The lower duct section external gas detector 76 detects combustible gases (such as hydrogen gas floating around the hull 1) flowing from the outside of the duct section 90 into the inside. The lower duct section external gas detector 76 is a combustible gas sensor such as a hydrogen gas sensor. The lower duct section external gas detector 76 is disposed on the opposite side of the lower duct section air supply device 75 from the lower duct section air supply pipe 74, that is, on the upstream side of the air flow from the outside of the duct section 90 to the inside. The lower duct section external gas detector 76 may be configured as a gas sensor that detects combustible gases other than hydrogen gas.

[0149] The lower duct section external gas detector 76 outputs a detection signal indicating, for example, the concentration of combustible gas to the control unit 12a. Based on the detection signal, the control unit 12a can determine whether the concentration of combustible gas is equal to or greater than a specified value. If the concentration is equal to or greater than the specified value, the control unit 12a controls the shutoff valve SV to stop the supply of fuel gas from the fuel tank 41 to the fuel cell 31. The specified value may be determined based on experiments and / or experience.

[0150] 7-3-2. Upper Duct Section The upper duct section 80 is disposed on the upper part of the deck 1a. Specifically, the upper duct section 80 is disposed on the deck 1a, spanning from the lower duct section 70 to the tank section 40. The upper duct section 80 accommodates a portion of the fuel gas discharge piping 71 and a portion of the gas fill piping 42.

[0151] Here, the "part of the fuel gas discharge piping 71" accommodated in the upper duct section 80 refers to the portion of the fuel gas discharge piping 71 that exits the lower duct section 70 and extends toward the vent pipe 10. Additionally, the "part of the gas fill piping 42" accommodated in the upper duct section 80 refers to the portion of the gas fill piping 42 that exits the lower duct section 70 and extends to the fuel gas fill port 82, which will be described later.

[0152] The upper duct section 80 is made of a material such as FRP, but may also be made of steel plate. The upper duct section 80 has a hollow shape. For example, the upper duct section 80 has a hollow, approximately rectangular parallelepiped shape. In this case, the outer walls constituting the upper duct section 80 include, for example, a top wall 80a, a bottom wall 80b, a front wall (not shown), a back wall (not shown), a side wall 80c, and a side wall 80d. However, the top, bottom, front, back, and side surfaces of the upper duct section 80 can be determined arbitrarily. Furthermore, the shape of the upper duct section 80 is not particularly limited as long as it has a space large enough to accommodate a portion of the fuel gas discharge pipe 71, etc. The upper duct section 80 can also be considered as a container, chamber, or box that accommodates a portion of the fuel gas discharge pipe 71, etc.

[0153] As described above, the fuel gas discharge pipe 71 communicates with the inside of the vent pipe 10. As a result, when the release valve 72 is opened, gas (e.g., fuel gas) inside the fuel gas discharge pipe 71 flows from the end 71a of the fuel gas discharge pipe 71 into the inside of the vent pipe 10 and is discharged from the vent pipe 10 to the outside of the ship. Here, it is desirable that the end 71a of the fuel gas discharge pipe 71 be positioned upward inside the vent pipe 10, that is, facing the open port side of the vent pipe 10. In this case, the discharge direction of the gas released from the end 71a of the fuel gas discharge pipe 71 is upward.

[0154] For example, if fuel gas is discharged sideways from the end 71a of the fuel gas discharge pipe 71, the discharged fuel gas may hit the inner wall surface of the vent pipe 10 and flow downward, which may result in malfunction of the tank compartment internal gas detector 44a in the tank compartment 40. By positioning the end 71a of the fuel gas discharge pipe 71 facing upward inside the vent pipe 10 as described above, it is possible to reduce the risk of malfunction of the tank compartment internal gas detector 44a due to fuel gas discharged from the end 71a.

[0155] An upper duct section air inlet 80e is provided in the bottom wall 80b of the upper duct section 80. The upper duct section air inlet 80e is connected to the duct connection portion 91. Therefore, the upper duct section 80 is connected to the lower duct section 70 via the upper duct section air inlet 80e, the duct connection portion 91, and the lower duct connection port 70f. Note that the upper duct section air inlet 80e may be provided in an outer wall of the upper duct section 80 other than the bottom wall 80b.

[0156] The upper duct section 80 has a vent pipe communication part 81. The vent pipe communication part 81 is a pipe that communicates the interior of the upper duct section 80 with the vent pipe 10. In FIG. 11 , the vent pipe communication part 81 is illustrated as having a shape that is bent upward from the horizontal direction, but the shape of the vent pipe communication part 81 is not limited to the shape shown in FIG. 11 . The reason that the vent pipe communication part 81 is bent upward is the same as the reason that the end part 71 a of the fuel gas discharge pipe 71 is bent upward, which is to reduce the risk of the tank compartment internal gas detector 44 a malfunctioning due to the fuel gas, which will be described later, being discharged from the vent pipe communication part 81.

[0157] The vent pipe 10 extends upward from the tank section 40 and is positioned inside the upper duct section 80. More specifically, the vent pipe 10 penetrates the bottom wall 80b of the upper duct section 80 to enter the interior of the vent pipe 10 and is positioned by penetrating through the top wall 80a. The vent pipe communication section 81 is provided inside the upper duct section 80, penetrating the side wall of the vent pipe 10. As a result, the upper duct section 80 is connected to the vent pipe 10 via the vent pipe communication section 81.

[0158] Therefore, the air inside the upper duct section 80 is discharged outside the ship via the vent pipe communication part 81 and the vent pipe 10. This allows ventilation inside the upper duct section 80. Furthermore, even if fuel gas leaks from the fuel gas discharge pipe 71 inside the upper duct section 80, the leaked fuel gas is discharged outside the ship via the vent pipe communication part 81 and the vent pipe 10. This prevents the leaked fuel gas from accumulating inside the upper duct section 80.

[0159] Furthermore, the upper duct section 80 and the lower duct section 70 are connected via a duct communication section 91. This allows (1) air taken into the lower duct 70 via the lower duct section air supply pipe 74, (2) fuel gas that has leaked for some reason from the fuel gas supply pipe 32 in the lower duct 70, and (3) air or fuel gas discharged from the fuel cell section 30 to the lower duct section 70 via the communication pipe 92 to be released outside the ship via the upper duct section 80 and the vent pipe 10. This makes it possible to prevent fuel gas from accumulating inside the lower duct section 70 and the fuel cell section 30.

[0160] The upper duct section 80 is provided with a fuel gas filling port 82 and a fuel gas check valve 83. The fuel gas filling port 82 is connected to the gas filling piping 42. The fuel gas check valve 83 is provided in the gas filling piping 42. More specifically, the fuel gas check valve 83 is located between the fuel gas filling port 82 and the branch point between the gas filling piping 42 and an inert gas piping 87 (described below).

[0161] When fuel gas is supplied from the fuel gas fill port 82, the fuel gas passes through the gas fill pipe 42 via the fuel gas check valve 83 and is supplied to the fuel tank 41 in the tank compartment 40. In this way, the fuel tank 41 is filled with fuel gas and stored therein. The fuel gas check valve 83 is provided to prevent backflow of fuel gas from the fuel tank 41 to the fuel gas fill port 82.

[0162] The upper duct section 80 is further provided with an inert gas filling port 84, an on-off valve 85, an inert gas check valve 86, and an inert gas pipe 87. The inert gas filling port 84 is connected to the inert gas pipe 87. The inert gas pipe 87 is provided within the upper duct section 80 and branches off from the gas filling pipe 42. The on-off valve 85 and the inert gas check valve 86 are provided in the inert gas pipe 87. In the inert gas pipe 87, the on-off valve 85 is located between the inert gas filling port 84 and the inert gas check valve 86.

[0163] The on-off valve 85 opens or closes the flow path of the inert gas pipe 87. In a configuration in which the inert gas check valve 86 is provided in the inert gas pipe 87, the on-off valve 85 may be omitted.

[0164] When inert gas is supplied to the inert gas fill port 84 while fuel gas is not being supplied to the fuel gas fill port 82, and the on-off valve 85 opens the flow path of the inert gas piping 87, the inert gas passes through the inert gas check valve 86 and is supplied to the fuel tank 41 in the tank compartment 40 via the inert gas piping 87 and the gas fill piping 42. Furthermore, the tank-side shutoff valve 43 opens the flow path of the fuel gas supply piping 32, the fuel cell-side shutoff valve 33 closes the flow path of the fuel gas supply piping 32, and the release valve 72 opens the flow path of the fuel gas discharge piping 71, so that the fuel gas remaining in the fuel tank 41 is discharged to the vent pipe 10 via the fuel gas supply piping 32 and the fuel gas discharge piping 71. This allows the fuel gas to be removed from the fuel tank 41 (purging process).

[0165] It should be noted that there may be a pipe that connects the gas filling pipe 42 directly to the fuel gas supply pipe 32 between the fuel tank 41 and the tank-side shutoff valve 43 (tank system). In this configuration, when purging the fuel tank 41 of inert gas, the fuel tank 41 is filled with inert gas while the tank-side shutoff valve 43 is closed, and then the tank-side shutoff valve 43 must be opened in order to facilitate the release of the inert gas from the fuel tank 41.

[0166] As described above, the fuel gas filling port 82 and the inert gas filling port 84 are provided in the upper duct section 80. More specifically, the fuel gas filling port 82 and the inert gas filling port 84 are located at the boundary surface between the inside and outside of the upper duct section 80. In other words, "the fuel gas filling port 82 and the inert gas filling port 84 are provided in the upper duct section 80" includes the case where the fuel gas filling port 82 and the inert gas filling port 84 are provided at the above-mentioned boundary surface of the upper duct section 80.

[0167] Also housed within the upper duct section 80 is an upper duct section internal gas detector 88. The upper duct section internal gas detector 88 is a fuel gas detector disposed within the upper duct section 80. For example, if the fuel gas is hydrogen gas, the upper duct section internal gas detector 88 is configured as a hydrogen gas detection sensor.

[0168] The upper duct section internal gas detector 88 is disposed on the top wall 80a located at the top of the upper duct section 80. Hydrogen gas, which serves as fuel gas, is lighter than air and rises. Therefore, even if fuel gas leaks inside the upper duct section 80, the leaked fuel gas can be reliably detected by the upper duct section internal gas detector 88. Note that, in order to more reliably detect fuel gas leaking inside the upper duct section 80, the upper duct section internal gas detector 88 may be disposed in a position close to the vent pipe communication portion 81.

[0169] When the upper duct section internal gas detector 88 detects fuel gas in the upper duct section 80, the detection signal is sent from the upper duct section internal gas detector 88 to the control unit 12a. As a result, the control unit 12a controls the shutoff valve SV provided in the fuel gas supply pipe 32 to stop the supply of fuel gas from the fuel tank 41 to the fuel cell 31.

[0170] Additionally, the upper duct section 80 may further house a fire detector for detecting a fire inside the upper duct section 80 .

[0171] (7-4. Supplementary information about vent pipes) A vent pipe internal gas detector 10a is provided inside the vent pipe 10, downstream of the outlet 81a of the vent pipe communication section 81. Note that the "downstream side" mentioned above refers to the downstream side of the air flow direction when the air inside the tank compartment 40 flows through the inside of the vent pipe 10 and is discharged overboard. For example, if the fuel gas is hydrogen gas, the vent pipe internal gas detector 10a is composed of a diffusion-type or suction-type hydrogen gas detection sensor. A detection signal from the vent pipe internal gas detector 10a is sent to the control section 12a.

[0172] For example, if the control unit 12a is outputting a signal (closure signal) to close the release valve 72 and the vent pipe internal gas detector 10a detects fuel gas even though the tank compartment internal gas detector 44a and the upper duct compartment internal gas detector 88 are not detecting fuel gas, it can be determined that the release valve 72 is not completely closing the flow path of the fuel gas discharge piping 71, that is, that the release valve 72 is malfunctioning. In this case, the control unit 12a can, for example, notify an external party to urge a maintenance person to inspect, repair, or replace the release valve 72. Note that examples of notifying an external party include displaying a monitor, outputting an alarm, and transmitting information to an external terminal.

[0173] [8. Fuel cell power generation control based on abnormality detection] As described above, the fuel cell ship SH of this embodiment is equipped with a plurality of fuel cells 31, and also with a plurality of fuel cell compartments 30 that house the fuel cells 31. Therefore, a plurality of cell compartment air supply devices 36 that supply air into the fuel cell compartments 30 are also provided, one for each fuel cell compartment 30. Therefore, the fuel cell ship SH of this embodiment can also be said to have the following configuration: That is, the fuel cell ship SH is equipped with a plurality of fuel cell compartments 30 in which a plurality of fuel cells 31 are separately installed, and a plurality of cell compartment air supply devices 36 that supply air into each of the plurality of fuel cell compartments 30.

[0174] The above-described control unit 12a of this embodiment also functions as a power generation control unit that controls the power generation of the multiple fuel cells 31. In particular, when at least one of the multiple battery compartment air supply devices 36 stops, the control unit 12a stops the power generation of the fuel cells 31 installed in the fuel cell compartment 30 to which air is supplied by the stopped battery compartment air supply device 36.

[0175] The determination of whether the battery compartment air supply device 36 has stopped can be made by the control unit 12a constantly or periodically monitoring the signal output by the battery compartment air supply device 36 when it is operating. For example, when the control unit 12a does not receive the signal even though the fuel cell 31 is operating (generating power), the control unit 12a can determine that the battery compartment air supply device 36 has stopped due to a malfunction or the like. In other words, the control unit 12a can determine whether the battery compartment air supply device 36 has stopped based on the signal output by the battery compartment air supply device 36 when it is operating.

[0176] With this control, if the battery compartment air supply device 36 stops for some reason (for example, a malfunction), it will be impossible to ventilate the fuel cell compartment 30 to which air is supplied by the stopped battery compartment air supply device 36, making it impossible to deal with fuel gas leaks in the fuel cell compartment 30. Therefore, when the battery compartment air supply device 36 stops, the control unit 12a, which serves as the power generation control unit, stops power generation by the fuel cell 31 in the fuel cell compartment 30 to which air is supplied by the stopped battery compartment air supply device 36. This reduces the risk of fuel gas leaks in the fuel cell compartment 30 due to operation of the fuel cell 31, even if only slightly, and makes it possible to ensure safety.

[0177] Furthermore, as described above, the fuel cell ship SH of this embodiment includes at least one tank compartment 40 in which a fuel tank 41 that stores fuel gas is installed, and a tank compartment air supply device 46 that supplies air to the inside of the tank compartment 40. In this configuration, when the tank compartment air supply device 46 stops, the control unit 12a stops power generation of the fuel cell 31, among the multiple fuel cells 31, that receives fuel gas from the fuel tank 41 installed in the tank compartment 40 to which the stopped tank compartment air supply device 46 supplies air.

[0178] For example, in the configuration shown in Figure 2, if the tank compartment air supply device 46 that supplies air into the tank compartment 40 that houses the fuel tank 41a stops due to a malfunction, the control unit 12a, which serves as the power generation control unit, stops power generation of the fuel cells 31a and 31b to which fuel gas is supplied from the fuel tank 41a.

[0179] Whether the tank compartment air supply device 46 has stopped can be determined by monitoring the power consumption of the tank compartment air supply device 46 or by the control unit 12a constantly or periodically monitoring the signal output during operation. For example, when the control unit 12a does not receive the signal even though the fuel cell 31 is operating (generating power), it can determine that the tank compartment air supply device 46 has stopped due to a malfunction or the like. In other words, the control unit 12a can determine whether the tank compartment air supply device 46 has stopped based on the signal output during operation by the tank compartment air supply device 46.

[0180] If the tank compartment air supply device 46 stops for some reason (for example, a malfunction), it is not possible to ventilate the tank compartment 40 to which the stopped tank compartment air supply device 46 supplies air. In this case, it becomes impossible to deal with a fuel gas leak within the tank compartment 40. Therefore, when the tank compartment air supply device 46 stops, the control unit 12a stops power generation of the fuel cell 31, among the multiple fuel cells 31, to which fuel gas is supplied from the fuel tank 41 within the tank compartment 40 to which air is supplied by the stopped tank compartment air supply device 46. This reduces, even if only slightly, the possibility of fuel gas leaking within the tank compartment 40 due to the supply of fuel gas to the fuel cell 31, thereby making it possible to ensure safety.

[0181] As described above, the fuel cell ship SH of this embodiment has a plurality of fuel cell compartments 30. Therefore, a plurality of cell compartment internal gas detectors 34a and cell compartment external gas detectors 37 are also provided, one for each fuel cell compartment 30. That is, the fuel cell ship SH has a plurality of fuel cell compartments 30, each of which has a plurality of fuel cells 31 installed separately, a plurality of cell compartment internal gas detectors 34a arranged inside each of the fuel cell compartments 30 to detect fuel gas, and a plurality of cell compartment external gas detectors 37 arranged outside each of the fuel cell compartments 30 to detect combustible gas flowing into the fuel cell compartment 30.

[0182] The control unit 12a, which serves as the power generation control unit in this embodiment, stops power generation of the fuel cell 31 in the fuel cell compartment 30 in which the reacted or failed battery compartment internal gas detector 34a or battery compartment external gas detector 37 is located when at least one of the multiple battery compartment internal gas detectors 34a and the multiple battery compartment external gas detectors 37 reacts with fuel gas or combustible gas or fails.

[0183] The determination of whether the battery compartment internal gas detector 34a and the battery compartment external gas detector 37 have failed can be made by the control unit 12a constantly or periodically monitoring the signals output from the battery compartment internal gas detector 34a and the battery compartment external gas detector 37 during operation (normal operation). For example, when the control unit 12a does not receive the above signals even though the fuel cell 31 is operating (generating power), the control unit 12a can determine that the battery compartment internal gas detector 34a or the battery compartment external gas detector 37 has failed (stopped). In other words, the control unit 12a can determine whether the battery compartment internal gas detector 34a or the battery compartment external gas detector 37 has failed (or stopped) based on the above signals output from the battery compartment internal gas detector 34a and the battery compartment external gas detector 37 during operation.

[0184] If the battery compartment internal gas detector 34a detects fuel gas (reacts with fuel gas), there is a high possibility that a fuel gas leak has occurred within the fuel cell compartment 30. Furthermore, if the battery compartment external gas detector 37 detects combustible gas (reacts with combustible gas), there is a high possibility that combustible gas will flow from the outside into the fuel cell compartment 30 and accumulate therein. In these cases, operating the fuel cell 31 installed in the fuel cell compartment 30 is undesirable from a safety perspective (there is a risk of an explosion for some reason). Furthermore, if the battery compartment air supply device 36 is not explosion-proof, there is a risk of the battery compartment air supply device 36 exploding.

[0185] Furthermore, if the battery compartment internal gas detector 34a or the battery compartment external gas detector 37 fails, it will be impossible to detect the fuel gas leak itself inside the fuel cell compartment 30 or the inflow of flammable gas from the outside to the inside of the fuel cell compartment 30. For this reason, operating the fuel cell 31 in this state is not recommended from the perspective of ensuring safety.

[0186] When at least one of the multiple internal gas detectors 34a of the battery compartment and the multiple external gas detectors 37 of the battery compartment reacts or fails, the control unit 12a, which serves as the power generation control unit, stops power generation of the fuel cell 31 in the fuel cell compartment 30 in which the internal gas detector 34a of the battery compartment or the external gas detector 37 of the battery compartment that has reacted or failed is located (inside or outside), thereby ensuring safety.

[0187] As described above, the fuel cell ship SH of this embodiment also includes at least one tank compartment 40 in which a fuel tank 41 that stores fuel gas is installed, a tank compartment internal gas detector 44a that is disposed inside the tank compartment 40 and detects fuel gas, and a tank compartment external gas detector 47 that is disposed outside the tank compartment 40 and detects flammable gas flowing into the tank compartment 40. In this configuration, when at least one of the tank compartment internal gas detector 44a and the tank compartment external gas detector 47 reacts with fuel gas or flammable gas or fails, the control unit 12a stops power generation of the fuel cells 31 that receive fuel gas from the fuel tank 41 in the tank compartment 40 in which the reacted or failed tank compartment internal gas detector 44a or tank compartment external gas detector 47 is disposed.

[0188] 2, when the tank compartment internal gas detector 44a or the tank compartment external gas detector 47 arranged corresponding to the tank compartment 40 accommodating the fuel tank 41c reacts with fuel gas or combustible gas, the control unit 12a serving as the power generation control unit stops power generation of the fuel cell 31c to which fuel gas is supplied from the fuel tank 41c. Also, when the tank compartment internal gas detector 44a or the tank compartment external gas detector 47 arranged corresponding to the tank compartment 40 accommodating the fuel tank 41c malfunctions, the control unit 12a also stops power generation of the fuel cell 31c to which fuel gas is supplied from the fuel tank 41c.

[0189] The determination of whether the tank compartment internal gas detector 44a and the tank compartment external gas detector 47 have failed can be made by monitoring the power consumption of the tank compartment internal gas detector 44a and the tank compartment external gas detector 47, or by the control unit 12a constantly or periodically monitoring the signals output from the tank compartment internal gas detector 44a and the tank compartment external gas detector 47 during operation (normal operation). For example, when the control unit 12a does not receive the above signals even though the fuel cell 31 is operating (generating power), it can determine that the tank compartment internal gas detector 44a or the tank compartment external gas detector 47 has failed (stopped). In other words, the control unit 12a can determine whether the tank compartment internal gas detector 44a or the tank compartment external gas detector 47 has failed (or stopped) based on the above signals output from the tank compartment internal gas detector 44a and the tank compartment external gas detector 47 during operation.

[0190] If the tank compartment internal gas detector 44a detects fuel gas (reacts with fuel gas), there is a high possibility that a fuel gas leak has occurred within the tank compartment 40. Furthermore, if the tank compartment external gas detector 47 detects combustible gas (reacts with combustible gas), there is a high possibility that combustible gas will flow from the outside into the tank compartment 40 and accumulate therein. In these cases, operating the fuel cell 31 to which fuel gas is supplied from the tank compartment 40 is undesirable from a safety perspective (there is a risk of an explosion for some reason). Furthermore, if the tank compartment air supply device 46 is not explosion-proof, there is a risk of the tank compartment air supply device 46 exploding.

[0191] Furthermore, if the tank compartment internal gas detector 44a or the tank compartment external gas detector 47 fails, it will be impossible to detect the fuel gas leak itself inside the tank compartment 40 or the inflow of flammable gas from the outside to the inside of the tank compartment 40. For this reason, operating the fuel cell 31 in this state is not recommended from the perspective of ensuring safety.

[0192] When at least one of the tank compartment internal gas detector 44a and the tank compartment external gas detector 47 reacts or fails, the control unit 12a, which functions as a power generation control unit, stops power generation of the fuel cell 31 among the multiple fuel cells 31 to which fuel gas is supplied from the fuel tank 41 in the tank compartment 40 to which the tank compartment internal gas detector 44a or tank compartment external gas detector 47 that has reacted or failed is located (inside or outside), thereby making it possible to ensure safety.

[0193] Furthermore, in this embodiment, a pair of duct sections 90 are provided on the starboard and port sides of the fuel cell ship SH. In this configuration, when at least one of the lower duct section internal gas detector 73, the upper duct section internal gas detector 88, and the lower duct section external gas detector 76 in at least one duct section 90 reacts with fuel gas or combustible gas or fails, the control unit 12a desirably stops power generation of the fuel cell 31 to which fuel gas is supplied from the fuel tank 41 through the duct section 90 in which the reacted or failed lower duct section internal gas detector 73, the upper duct section internal gas detector 88, or the lower duct section external gas detector 76 is located.

[0194] If the lower duct section internal gas detector 73 or the upper duct section internal gas detector 88 detects fuel gas (reacts with fuel gas), there is a high possibility that a fuel gas leak has occurred in the duct section 90. Furthermore, if the lower duct section external gas detector 76 detects combustible gas (reacts with combustible gas), there is a high possibility that combustible gas will flow from the outside into the duct section 90 and accumulate therein. In these cases, operating the fuel cell 31 to which fuel gas is supplied from the tank section 40 through the duct section 90 is undesirable from a safety perspective (there is a risk of an explosion for some reason). Furthermore, if the lower duct section air supply device 75 is not explosion-proof, there is a risk of an explosion in the lower duct section air supply device 75. By stopping power generation of the affected fuel cell 31 as described above, efforts can be made to ensure safety.

[0195] [9. Limitations on power input to propulsion equipment] As mentioned above, in a fuel cell ship SH equipped with multiple fuel cells 31, even if at least one fuel cell 31 is forced to shut down due to an event such as a fuel gas leak inside the hull 1 while sailing, the propulsion device 6 can be driven by at least one of the power output from the other fuel cells 31 and the power supplied from the storage battery 51, and sailing can continue.

[0196] If the fuel cell 31 makes an emergency stop and the input power to the propulsion device 6 drops suddenly, the speed of the fuel cell ship SH drops sharply and passengers are more likely to tip over if the output power from the storage battery 51 is low. This is because a fuel cell ship SH traveling on the sea or rivers faces greater resistance from the water surface when traveling, unlike vehicles traveling on roads.

[0197] Therefore, in a fuel cell ship SH equipped with multiple fuel cells 31, at least one storage battery 51, and a propulsion device 6, as in this embodiment, the control unit 12a monitors the temperature information and SOC (State Of Charge) data of the storage battery 51, calculates the amount of power that can be output from the storage battery 51 based on the temperature information and SOC data, and sets the upper limit value of the power to the upper limit value of the input power value to the propulsion device 6 (proportional to at least one of the rotation speed and torque).

[0198] 2, if a fuel gas leak is detected in the tank compartment 40 that houses the fuel tank 41b, the control unit 12a stops power generation from the fuel cells 31a and 31b, which receive fuel gas from the fuel tank 41b, as described above. In this case, the remaining fuel cells 31c, 31d, and 31e, together with the storage battery 51, must provide the power needed to operate the propulsion device 6. Furthermore, if the fuel cells 31c, 31d, and 31e stop functioning for some reason, the storage battery 51 alone must provide the power needed to operate the propulsion device 6.

[0199] Therefore, during normal operation (normal navigation), it is desirable that the control unit 12a set the upper limit of the power input from at least one of the fuel cells 31 and the storage battery 51 to the propulsion device 6 (particularly the propulsion motor 6b) to the output upper limit of the storage battery 51. In this case, even if, for example, all of the fuel cells 31 are forced to stop for some reason, the propulsion device 6 can continue to operate using the power output from the storage battery 51 without causing a sudden drop in the sailing speed of the fuel cell ship SH. In other words, even if a fuel cell 31 is forced to stop while sailing, a sudden drop in sailing speed can be prevented. As a result, the risk of passengers falling over when a fuel cell 31 is forced to stop can be reduced.

[0200] [10. Other] In this embodiment, gaseous fuel gas is used as the fuel supplied from the fuel tank 41 to the fuel cell 31, but the fuel is not limited to gas and may be liquid. When liquid fuel is used, if the liquid fuel leaks from the piping, the leaked liquid fuel vaporizes and becomes gas (fuel gas).

[0201] In this embodiment, a configuration has been described in which the fuel cell ship SH has the duct section 90, but the duct section 90 does not have to be installed. For example, if vent pipes are provided corresponding to each of the tank section 40 and the fuel cell section 30, the installation of the duct section 90 can be omitted (because there is no need to ensure a flow path from the fuel cell section 30 to the vent pipe 10).

[0202] Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to these, and the invention can be expanded or modified without departing from the spirit of the invention. [Industrial Applicability]

[0203] The present invention can be used in, for example, a fuel cell ship. [Explanation of symbols]

[0204] 1. Hull 6 Propulsion device 12a Control section (deterioration rate control section, power generation control section) 31 Fuel Cell 41 Fuel tank 41a Individual tank (fuel tank) 41b Individual tank (fuel tank) 51 Storage battery 100 Power supply section SH fuel cell ship

Claims

1. a propulsion device that generates propulsive force on the hull using electricity; a power supply unit that supplies the power to the propulsion device, the power supply unit has a plurality of fuel cells that generate electricity through an electrochemical reaction of fuel and at least one storage battery; The fuel cell ship comprises: a deterioration rate control unit that adjusts a deterioration rate indicating the degree of deterioration of each of the plurality of fuel cells; When the time when the deterioration rate of each fuel cell reaches a deterioration rate suitable for replacement due to deterioration of each fuel cell is set as the target replacement time, and the predetermined replacement time for each fuel cell is set as the scheduled replacement time, the deterioration rate control unit adjusts the deterioration rate of at least one of the fuel cells so that the estimated replacement time approaches or coincides with the scheduled replacement time for each of the fuel cells; The deterioration rate control unit adjusts the deterioration rate of the fuel cell when the power load consumed by the fuel cell ship becomes equal to or less than a first threshold value determined based on the lower limit of the power generation output of the fuel cell at which the rate of deterioration of the fuel cell becomes equal to or less than a predetermined value and the number of fuel cells installed, and varies the way in which the deterioration rate is adjusted depending on the expected time for which the state below the first threshold will continue.

2. The fuel cell ship according to claim 1 , comprising a plurality of pairs of the propulsion device and the power supply unit.

3. Further comprising a plurality of fuel tanks for storing the fuel; 3. The fuel cell ship according to claim 1, wherein the plurality of fuel tanks includes a plurality of individual tanks connected to two or more identical fuel cells among the plurality of fuel cells.

4. A fuel cell ship as described in any one of claims 1 to 3, wherein the deterioration rate control unit adjusts the deterioration rate of the fuel cell when the power load consumed by the fuel cell ship is equal to or greater than a second threshold determined based on the rated output of the fuel cell and the number of fuel cells installed, and sets the power generation output of a fuel cell among the plurality of fuel cells for which deterioration is to be suppressed to be equal to or less than the rated output.

5. a plurality of fuel cell compartments in which each of the plurality of fuel cells is separately installed; a plurality of fuel cell compartment air supply devices that supply air to the interiors of the plurality of fuel cell compartments; a power generation control unit that controls power generation by the plurality of fuel cells, 3. The fuel cell ship according to claim 1, wherein the power generation control unit stops power generation of the fuel cell installed in the fuel cell compartment to which air is supplied by the stopped battery compartment air supply device when at least one of the plurality of battery compartment air supply devices stops.

6. at least one tank compartment in which a fuel tank containing the fuel is installed; a tank compartment air supply device that supplies air to the inside of the tank compartment, 6. The fuel cell ship described in claim 5, wherein, when the tank compartment air supply device stops, the power generation control unit stops power generation of a fuel cell among the plurality of fuel cells to which fuel is supplied from the fuel tank installed in the tank compartment to which air is supplied by the stopped tank compartment air supply device.

7. a plurality of fuel cell compartments in which each of the plurality of fuel cells is separately installed; a plurality of gas detectors disposed inside the plurality of fuel cell compartments, respectively, for detecting fuel gas, which is the gaseous state of the fuel; a plurality of fuel cell compartment external gas detectors disposed outside the plurality of fuel cell compartments, respectively, for detecting combustible gas flowing into the fuel cell compartments; a power generation control unit that controls power generation by the plurality of fuel cells, 3. The fuel cell ship according to claim 1, wherein the power generation control unit stops power generation of a fuel cell in a fuel cell compartment among the plurality of fuel cells in which the battery compartment internal gas detector or the battery compartment external gas detector that has reacted or failed is located when at least one of the plurality of battery compartment internal gas detectors and the plurality of battery compartment external gas detectors reacts with the fuel gas or the combustible gas or fails.

8. at least one tank compartment in which a fuel tank containing the fuel is installed; a tank compartment internal gas detector disposed inside the tank compartment and detecting fuel gas, which is the gaseous state of the fuel; a tank compartment external gas detector disposed outside the tank compartment and detecting flammable gas flowing into the tank compartment; 8. The fuel cell ship according to claim 7, wherein the power generation control unit stops power generation of a fuel cell among the plurality of fuel cells to which fuel is supplied from the fuel tank in the tank compartment in which the tank compartment internal gas detector or the tank compartment external gas detector that has reacted or failed is located when at least one of the tank compartment internal gas detector and the tank compartment external gas detector reacts with the fuel gas or the combustible gas or fails.

9. a propulsion device that generates propulsive force on the hull using electricity; a power supply unit that supplies the power to the propulsion device, the power supply unit has a plurality of fuel cells that generate electricity through an electrochemical reaction of fuel and at least one storage battery; A fuel cell ship, wherein an upper limit value of the power supplied from the power supply unit to the propulsion device is set to an upper limit value of the power that can be output from the storage battery.

10. Further comprising a plurality of fuel tanks for storing the fuel; 10. The fuel cell ship according to claim 9, wherein the plurality of fuel tanks includes a plurality of individual tanks connected to two or more identical fuel cells among the plurality of fuel cells.

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