Control system for fuel cell ships

Abstract

This provides a control system for fuel cell ships that does not require heaters for cold starting or switching valves for bypass channels. [Solution] A control system for a fuel cell ship comprising: a seawater line and seawater pump for taking in seawater from outside the hull; a coolant line and coolant pump for circulating coolant between a heat exchanger on the seawater line and a fuel cell module; and a battery for storing electricity generated by the fuel cell module and supplying power to an electric motor, seawater pump, coolant pump, and auxiliary equipment of the fuel cell module, wherein the system is configured to execute a startup routine in which the seawater pump and coolant pump are started at startup, the seawater pump is stopped and the fuel cell module is started when the coolant temperature becomes equal to or higher than the seawater temperature, and the seawater pump is restarted when the coolant temperature reaches the steady-state operating temperature of the fuel cell module.

Description

Technical Field

[0001] The present invention relates to a control system for a fuel cell ship.

Background Art

[0002] A fuel cell is a power generation device that generates electricity through the oxidation-reduction reaction of fuel hydrogen and oxygen in the air, and heat and generated water are generated during power generation. In a solid polymer fuel cell (PEFC) that uses a solid polymer membrane as an electrolyte, the operating temperature needs to be maintained at 80°C or lower, and a cooling system is required for temperature adjustment.

[0003] On the other hand, since generated water remains on the surface of the membrane electrode assembly (MEA) in the fuel cell module when the device stops, when stored at a temperature below the freezing point, the remaining generated water freezes, and hydrogen and air do not flow normally during the next startup, resulting in a problem that power generation cannot be performed. Patent Document 1 discloses a configuration in which a heater attached to a cooling line is used to heat the fuel cell module, and in that case, a configuration in which a bypass flow path for bypassing a radiator for cooling is switched.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Disclosure of the Invention

Problems to be Solved by the Invention

[0005] However, a system that depends on a heater for low-temperature startup not only has a large power consumption for heating by the heater, but also requires a bypass flow path and a switching valve to the bypass flow path, resulting in a problem that the system becomes complicated.

[0006] The present invention has been made in view of the above-mentioned limitations of the prior art, and its purpose is to provide a control system for a fuel cell ship that does not require a heater for low-temperature starting or a switching valve for a bypass flow path. [Means for solving the problem]

[0007] In order to solve the above problems, the inventors of this invention conducted diligent research and discovered that even when the air temperature is below freezing, the temperature of seawater only cools down to about 5°C. Therefore, they found that a low-temperature starting system can be constructed inexpensively by utilizing the seawater present around a fuel cell ship, which led to the invention of this invention.

[0008] In other words, the present invention is Fuel cell module and The electric motor serves as the power source that generates thrust for the hull, A seawater line and a seawater pump for taking in seawater from outside the hull, A coolant line and a coolant pump for circulating coolant between the heat exchanger on the seawater line and the fuel cell module, A control system for a fuel cell ship, comprising a battery for storing electricity generated by the fuel cell module and supplying power to the electric motor and auxiliary equipment of the fuel cell module, including the seawater pump and the coolant pump, The control system for a fuel cell ship is configured to execute a startup routine in which the seawater pump and the coolant pump are started at startup, the seawater pump is stopped and the fuel cell module is started when the coolant temperature reaches or exceeds the seawater temperature, and the seawater pump is restarted when the coolant temperature reaches the steady-state operating temperature of the fuel cell module. [Effects of the Invention]

[0009] The control system for a fuel cell ship according to the present invention is based on the knowledge that even when the air temperature is below freezing, the seawater temperature only cools down to about 5°C. As described above, the system starts the seawater pump and coolant pump at startup to raise the coolant temperature through heat exchange with seawater, and when the coolant temperature reaches or exceeds the seawater temperature, the seawater pump is stopped and the fuel cell module is started. Therefore, even when the air temperature is below freezing, the coolant temperature can be raised to around 5°C, which is sufficient to start the fuel cell module, using seawater. This eliminates the need for heaters for low-temperature starting and switching valves for bypass channels, allowing for a simple and inexpensive low-temperature starting system to be constructed.

[0010] Furthermore, by temporarily stopping the seawater pump and starting the fuel cell module when the coolant temperature exceeds the seawater temperature, and then restarting the seawater pump when the coolant temperature reaches the steady-state operating temperature, the steady-state operating temperature can be reached more quickly compared to keeping the seawater pump running continuously, minimizing the operating time and power consumption of the seawater pump. [Brief explanation of the drawing]

[0011] [Figure 1] This is a plan view showing a fuel cell ship according to an embodiment of the present invention. [Figure 2] This flowchart shows the control of a fuel cell ship during low-temperature startup according to an embodiment of the present invention. [Modes for carrying out the invention]

[0012] Embodiments of the present invention will be described in detail below with reference to the drawings. In Figure 1, the fuel cell ship 1 according to an embodiment of the present invention has an electric outboard motor 2 equipped with a propeller and an electric motor for generating thrust, which is steerably mounted to the rear 12 of the hull, and is equipped with a fuel cell module 3 and its cooling system 4 for generating electricity to supply power to the electric outboard motor 2.

[0013] The fuel cell module 3 includes a fuel cell stack 30, hydrogen-related equipment such as a hydrogen fuel tank 31 and a hydrogen circulation pump 32, and oxygen-related equipment such as an air filter 34 and a blower 33. Together with electrical equipment such as a battery 5 and a power converter 6 for storing the electricity generated by the fuel cell module 3 and supplying power to the electric outboard motor 2 and auxiliary equipment of the fuel cell module 3, and a control unit 40, the fuel cell system is formed.

[0014] The battery 5 preferably includes a main battery (such as a LIB) for supplying power to the motor of the electric outboard motor 2, and a low-voltage battery for supplying power to the auxiliary equipment of the fuel cell module 3 (hydrogen circulation pump 32, blower 33, seawater pump 43, coolant pump 47) and the control unit 40, and the power converter 6 may also include a step-down converter and a step-up converter.

[0015] The fuel cell stack 30 is constructed by stacking a large number of unit cells, each of which has a hydrogen-side separator and an air-side separator stacked on each side of a membrane electrode assembly (MEA) via a gas diffusion layer, and a coolant flow path is provided between each unit cell.

[0016] The cooling system 4 includes a seawater line 41, which includes a seawater pump 43 for pressurizing seawater taken in from a water intake 42 at the bottom of the hull and sending it to the heat exchanger 44 and discharging it from a discharge port 45, and a coolant line 46, which includes a coolant pump 47 for circulating coolant between the fuel cell module 3 (fuel cell stack 30) and the heat exchanger 44.

[0017] As described later, in order to perform the low-temperature starting process using the cooling system 4, it is preferable that the heat exchanger 44 and the coolant line 46 are covered with insulating material and insulated from the outside air. The coolant in the coolant line 46 may be clean water (pure water) with low electrical conductivity or an antifreeze containing an antifreeze agent such as ethylene glycol.

[0018] A temperature sensor 48 is provided in the coolant line 46. The control unit 40 determines the frozen state of the generated water in the fuel cell module 3 based on the coolant temperature detected by the temperature sensor 48, and controls the coolant pump 47 and the seawater pump 43 to perform cooling, i.e., temperature control, during low-temperature startup and steady operation.

[0019] Figure 2 is a flowchart showing the low-temperature startup routine of the fuel cell ship 1 equipped with the cooling system 4 as described above. When starting the fuel cell ship 1, if the temperature of the coolant detected by the temperature sensor 48 is lower than a predetermined low temperature (for example, 5°C), first, the seawater pump 43 is started to take in seawater from the water intake 42 into the seawater line 41 and circulate the seawater through the heat exchanger 44 (S1).

[0020] Next, the coolant pump 47 is started to circulate the coolant in the coolant line 46 between the fuel cell stack 30 and the heat exchanger 44 (S2). When the temperature of the coolant rises due to heat exchange with seawater in the heat exchanger 44 and the coolant temperature becomes higher than the seawater temperature (S3; Yes), it is determined that the ice in the fuel cell module 3 has melted, the seawater pump 43 is stopped (S4), and the fuel cell module 3 is started (S5).

[0021] When the fuel cell module 3 is started, power is generated by the oxidation-reduction reaction of fuel hydrogen and oxygen in the air, and heat is generated at the same time. As the temperature of the fuel cell stack 30 rises, the cooling water temperature also rises. After that, when the cooling water temperature reaches a predetermined target temperature (for example, 60°C) corresponding to the steady operation temperature (S6; Yes), the seawater pump 43 is restarted (S7), and then, the seawater pump 43 and the coolant pump 47 are controlled to be turned on and off so that the cooling water temperature is maintained at the steady operation temperature (about 60 to 80°C), and the operation shifts to steady operation.

[0022] By executing the low-temperature starting routine described above, even at sub-zero temperatures, the coolant temperature can be raised to a starting temperature using seawater at 5°C or higher, utilizing the seawater line 41 which is normally used for cooling. This eliminates the need for a heater in the coolant line 46 in non-cold-weather specifications. Furthermore, even in specifications that have a heater in the cooling line 46, the power used for the heater can be reduced.

[0023] For example, if the seawater temperature is below a predetermined temperature (e.g., 3°C) at startup, the seawater pump 43 and the coolant pump 47 are started, and then when the coolant temperature reaches the seawater temperature (e.g., 3°C), the seawater pump 43 is stopped and the heater of the coolant line 46 is started. After the fuel cell module 3 is started, the heater is stopped when the coolant temperature rises to or above a second predetermined temperature, thereby minimizing the use of the heater by utilizing the temperature difference between the seawater and the coolant.

[0024] In either configuration, a bypass line or a three-way valve for switching to the bypass line is not required in the coolant line 46, simplifying the system. This reduces the time until departure is possible even at sub-zero temperatures, prevents deterioration of the membrane electrode assembly (MEA), and is advantageous for extending the lifespan of the fuel cell system.

[0025] Although several embodiments of the present invention have been described above, it should be noted that the present invention is not limited thereto, and various further modifications and changes are possible within the scope of the present invention based on the technical idea of ​​the present invention. [Explanation of symbols]

[0026] 1 Fuel cell ship 2 electric outboard motor 3. Fuel cell system 4. Cooling System 30 Fuel Cell Modules 40 Control Unit 41 Seawater Line 42 Water intake 43 Seawater pump 44 Heat exchanger 45 Drain port 46 Coolant lines 47 Coolant pump 48 Temperature Sensor

Claims

1. Fuel cell module and The electric motor serves as the power source that generates thrust for the hull, A seawater line and a seawater pump for taking in seawater from outside the hull, A coolant line and a coolant pump for circulating coolant between the heat exchanger on the seawater line and the fuel cell module, A control system for a fuel cell ship, comprising a battery for storing electricity generated by the fuel cell module and supplying power to the electric motor and auxiliary equipment of the fuel cell module, including the seawater pump and the coolant pump, A control system for a fuel cell vessel, characterized in that it is configured to execute a startup routine in which the seawater pump and the coolant pump are started at startup, the seawater pump is stopped and the fuel cell module is started when the coolant temperature reaches or exceeds the seawater temperature, and the seawater pump is restarted when the coolant temperature reaches the steady-state operating temperature of the fuel cell module.

2. A control system for a fuel cell ship according to claim 1, configured to stop the seawater pump and start the heater of the coolant line when the coolant temperature reaches or exceeds the seawater temperature if the seawater temperature is below a first predetermined temperature at startup, and to stop the heater when the coolant temperature reaches or exceeds a second predetermined temperature.

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