Aircraft

Abstract

To provide a flying object capable of inhibiting ignition in a secondary battery due to overcharging.SOLUTION: A flying object includes a fuel cell, a secondary battery, a motor for driving a propulsion propeller, an air resistance increasing device capable of increasing air resistance, and a control section. The fuel cell, the secondary battery, and the motor are electrically connected. The motor obtains power from at least one of the fuel cell and the secondary battery to be driven. When the fuel cell generates the amount of power exceeding the amount of power consumed, the control section performs power consumption control of increasing the amount of power supplied to the motor from the fuel cell, actuating the air resistance increasing device to increase the air resistance, and maintaining a flight state.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] This application relates to air vehicles. [Background technology]

[0002] In recent years, aircraft equipped with fuel cell systems have been developed. For example, Patent Document 1 describes an aircraft power supply system including a battery and a fuel cell. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-15423 A Summary of the Invention [Problem to be solved by the invention]

[0004] In aircraft equipped with fuel cells and secondary batteries, if surplus electricity generated to avoid high potential of the fuel cells, refresh operation, and rapid warm-up is charged to the secondary battery, there is a problem of fire due to overcharging. Such a problem is of great importance to safety.

[0005] In view of the above, a main object of the present application is to provide an aircraft capable of preventing secondary batteries from catching fire due to overcharging. [Means for solving the problem]

[0006] As one means for solving the above problems, the present disclosure provides an aircraft comprising a fuel cell, a secondary battery, a motor that drives a propulsion propeller, an air resistance increasing device capable of increasing air resistance, and a control unit, wherein the fuel cell, secondary battery, and motor are electrically connected, and the motor is driven by obtaining power from at least one of the fuel cell and the secondary battery, and when the fuel cell generates an amount of power that exceeds the amount of power consumed, the control unit increases the amount of power supplied from the fuel cell to the motor, while activating the air resistance increasing device to increase air resistance, and maintains a flying state, thereby performing power consumption control.

[0007] In the above flying object, the air resistance increasing device may be a secondary control surface, and the air resistance may be increased by opening the secondary control surface in both directions during power consumption control. In addition, when the fuel cell generates an amount of power that exceeds the amount of power consumed, and the amount of power that exceeds the amount of power consumed is set as surplus power, the control unit may perform power consumption control when the amount of surplus power exceeds a first threshold, and may stop power consumption control when the amount of surplus power falls below a second threshold. Effect of the Invention

[0008] The aircraft disclosed in the present disclosure performs a predetermined power consumption control when the fuel cell generates an amount of power that exceeds the amount of power consumed, i.e., when surplus power occurs, thereby consuming the surplus power and preventing the secondary battery from catching fire due to overcharging. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic diagram of an aircraft 10. (a) is a front view of the aircraft 10, and (b) is a top view of the aircraft 10. [Diagram 2] 1 is a schematic diagram of the voltage system of the aircraft 10. [Diagram 3] FIG. 11 is a diagram for explaining power consumption control in which a threshold value is set. [Figure 4] 13 is an example of a processing routine for power consumption control in which a threshold value is set. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The aircraft of the present disclosure will be described using an aircraft 10 as one embodiment. A schematic diagram of the aircraft 10 is shown in Fig. 1. Fig. 1(a) is a front view of the aircraft 10, and Fig. 1(b) is a top view of the aircraft 10. Fig. 2 is a schematic diagram of the voltage system of the aircraft 10.

[0011] The flying object 10 is not particularly limited as long as it is an object that can fly in the air. For example, the flying object 10 includes aircraft such as general aircraft, light aircraft, and drones. FIG. 1 shows the flying object 10 in the form of an aircraft.

[0012] The aircraft 10 comprises a fuel cell 1, a secondary battery 2, a motor 3 that drives a propulsion propeller 4, an air resistance increasing device capable of increasing air resistance, and a control unit. As shown in Fig. 2, the fuel cell 1, the secondary battery 2, and the motor 3 are electrically connected, and the motor 3 is driven by obtaining power from at least one of the fuel cell 1 and the secondary battery 2. Note that Fig. 2 also shows an FDC (DC / DC converter for fuel cell) and an INV (inverter), which are general devices.

[0013] The fuel cell 1 is formed by stacking a plurality of fuel cell units (sometimes simply referred to as "unit cells") in series. The unit cell has an electrolyte membrane, an anode disposed on one side of the electrolyte membrane, and a cathode disposed on the other side of the electrolyte membrane. Specifically, catalyst layers are disposed on both sides of the electrolyte membrane, a diffusion layer is disposed on the outside of the catalyst layer, and a separator having a fuel gas flow path and an oxidant gas flow path is disposed on the outside of the diffusion layer. Such a fuel cell has a general configuration. Here, in the fuel cell, the catalyst layer and the diffusion layer function as the anode or cathode.

[0014] The electrolyte membrane, catalyst layer, diffusion layer, and separator arranged in the fuel cell are not particularly limited, and known materials can be used. For example, the electrolyte membrane can be an ion exchange membrane made of a solid polymer material. The catalyst layer can be a platinum-based catalyst. The diffusion layer can be a porous material such as a carbon material. The separator can be a metal material such as stainless steel, or a carbon material such as a carbon composite material.

[0015] In the fuel cell 10, an electrochemical reaction occurs when a fuel gas is supplied to the anode and an oxidant gas is supplied to the cathode, generating electricity. The generated electricity is used to charge the secondary battery 2 and drive the motor 3. It may also be used for other devices in the aircraft 10.

[0016] The secondary battery 2 is a known secondary battery such as a lithium ion secondary battery. The secondary battery 2 serves to drive the motor 3 and to store the power generated by the fuel cell 1. The secondary battery 2 may also be used for other devices of the aircraft 10.

[0017] The air resistance increasing device is not particularly limited as long as it is a control surface that can increase the air resistance of the aircraft 10. For example, a secondary control surface 5 can be used. A secondary control surface is a control surface that is an auxiliary control surface other than a main control surface. Examples of the secondary control surface 5 include spoilers, flaps, and tabs. FIG. 1 shows an example in which a spoiler is used as the secondary control surface 5. In FIG. 1, the secondary control surface 5 is provided on a pair of main wings 6, a pair of tails 7, and a vertical tail 8. The secondary control surface 5 is composed of a pair of flat plates, and usually, one or both of the flat plates are opened to change the air resistance and control the movement of the aircraft 10. As shown in FIG. 1, the secondary control surfaces 5 provided on the main wings 6 and tail 7 have flat plates arranged above and below, and the secondary control surface 5 provided on the vertical tail 8 has flat plates arranged on the left and right. This configuration is similar to the configuration of a general secondary control surface.

[0018] The control unit is a computer system equipped with a CPU, ROM, RAM, input / output interface, etc., and controls each part of the aircraft 10.

[0019] As described above, the power generated by the fuel cell 1 may be used to charge the secondary battery 2. Usually, the power generation of the fuel cell 1 is controlled so that the secondary battery 2 does not exceed the allowable charging power. However, when power is generated to avoid a high potential of the fuel cell 1, for refresh operation, rapid warm-up, etc., and the amount of power generated exceeds the amount of power consumed, if the amount of power exceeding the amount of power consumed (surplus power) is charged to the secondary battery 2, the amount of power may exceed the allowable charging power, resulting in overcharging. If the secondary battery 2 is overcharged, there is a problem that it may ignite. Suppressing ignition of such secondary battery 2 is an important issue for improving the safety of the flying object 10.

[0020] Therefore, in the flying object 10, when the fuel cell 1 generates an amount of power that exceeds the amount of power consumed, the control unit increases the amount of power supplied from the fuel cell 1 to the motor 3, while activating the air resistance increasing device to increase air resistance and maintain the flying state, thereby performing power consumption control. This allows the flying state to be maintained while consuming surplus power, and makes it possible to prevent the secondary battery from catching fire due to overcharging.

[0021] Here, each term will be explained. The "allowable charging power amount" is the amount of charging that does not result in overcharging. In other words, if the amount of charging exceeds the allowable charging power amount, the secondary battery 2 will be overcharged. "Power consumption" refers to the amount of power consumption required to operate the aircraft 10. The amount of power consumption varies depending on the operating state of the aircraft 10, etc. The term "surplus power" refers to the amount of power that exceeds the amount of power consumed when the fuel cell 1 generates an amount of power that exceeds the amount of power consumed.

[0022] "Avoiding high potential" refers to power generation to prevent the voltage of the fuel cell 1 from rising above a predetermined voltage. This is because when the voltage of the fuel cell 1 rises to the predetermined voltage, the metal (e.g., platinum) used in the catalyst layer is ionized and eluted. The "refresh operation" refers to power generation for lowering the voltage of the fuel cell 1 in order to remove the oxide film of the metal (eg, platinum) used in the catalyst layer. "Rapid warm-up" refers to power generation for self-heating the fuel cell 1 to prevent it from freezing.

[0023] "Power consumption control" refers to control performed by the control unit to consume surplus power. In power consumption control, thrust increase control is performed to increase the amount of power supplied from the fuel cell 1 to the motor 3, and air resistance increase control is performed to increase air resistance by operating the air resistance increase device. At this time, thrust increase control and air resistance increase control must be performed to maintain a flight state. "Maintaining a flight state" means that there is almost no change in thrust and lift before and after the power consumption control. "Almost no change" means that the change in thrust and lift before and after the power consumption control is within ±10%, preferably within ±5%.

[0024] Therefore, the power consumption control can be said to be a control that consumes surplus power while maintaining the flying state by increasing the thrust or lift of the flying body 10 and increasing the air resistance. Here, the order in which the thrust increase control and the air resistance increase control are performed is not particularly limited, and they may be performed sequentially or simultaneously. When performing them sequentially, either control may be performed first.

[0025] The amount of increase in the amount of power supplied to the motor 3 is not particularly limited, but may be a part or the entire amount of surplus power. When the air resistance device is a secondary control surface 5, the air resistance can be increased by opening one or both of the secondary control surfaces 5. Preferably, the secondary control surfaces 5 are opened in both directions. When the aircraft 10 is equipped with multiple secondary control surfaces 5 as shown in FIG. 1, all of the secondary control surfaces 5 equipped on the aircraft 10 may be opened, or some of the secondary control surfaces 5 may be opened. By using the secondary control surfaces 5 as an air resistance increasing device, power consumption control can be performed without providing an additional device.

[0026] The control unit may also perform power consumption control as follows. That is, the control unit may perform power consumption control when the amount of surplus power exceeds a first threshold, and may stop power consumption control when the amount of surplus power falls below a second threshold. This makes it possible to reduce the number and duration of power consumption control while preventing overcharging of the secondary battery, thereby improving fuel efficiency.

[0027] The "first threshold" can be set appropriately from the range of the chargeable electric energy that can suppress overcharging of the secondary battery 1 by performing power consumption control when surplus power occurs, taking fuel consumption into consideration. For example, it can be appropriately selected from the range of 30% to 70%, preferably 40% to 60%, of the chargeable electric energy. The "second threshold" can be set appropriately from the range of the chargeable electric energy that can prevent overcharging of the secondary battery 1 without performing power consumption control when surplus power occurs, taking fuel consumption into consideration. For example, it can be appropriately selected from the range of 0% to 30%, preferably 10% to 20%, of the chargeable electric energy.

[0028] Fig. 3 shows a diagram for explaining power consumption control with a threshold set. (1) and (2) in Fig. 3 indicate the first threshold and the second threshold, respectively. Also, (A) and (B) in Fig. 3 indicate the power consumption control in progress and the power consumption control stopped, respectively. As shown in Fig. 3, the power consumption control with a threshold set is controlled to draw a hysteresis loop.

[0029] An example of a processing routine for power consumption control in which a threshold value is set is shown in Fig. 4. As shown in Fig. 4, the control unit 50 includes steps S1 to S6, and the control unit 50 repeatedly performs these steps.

[0030] In step S1, it is determined whether the amount of surplus power exceeds a first threshold value. If it is determined that the amount of surplus power exceeds the first threshold value, power consumption control (steps S2 and S3) is performed.

[0031] In process S2, thrust increase control is performed to increase the amount of power supplied from the fuel cell 1 to the motor 3. In process S3, air resistance increase control is performed to increase air resistance by operating the air resistance increase device. Here, when performing both processes S2 and S3, control is performed to maintain the flight state.

[0032] In step S4, it is determined whether the amount of surplus power is below the second threshold value. If the amount of surplus power is below the second threshold value, power consumption control is stopped (steps S5 and S6).

[0033] In step S5, the thrust increase control is stopped. In step S6, the air resistance increase control is stopped. Here, when performing both steps S5 and S6, it is preferable to perform control so as to maintain the flight state.

[0034] The flying object of the present disclosure has been described above using the flying object 10 as one embodiment. The flying object of the present disclosure performs a predetermined power consumption control when the fuel cell generates an amount of power that exceeds the amount of power consumed, i.e., when surplus power occurs. Therefore, the flying object of the present disclosure can consume the surplus power while maintaining the flying state, and can suppress the secondary battery from catching fire due to overcharging. [Explanation of symbols]

[0035] 1 fuel cell 2 Secondary battery 3 Motor 4 Propellers 5 Secondary Control Surfaces 6. Wing 7 tail fin 8 Vertical stabilizer 10 Flying Objects

Claims

1. The vehicle is provided with a fuel cell, a secondary battery, a motor for driving a propulsion propeller, an air resistance increasing device capable of increasing air resistance, and a control unit, the fuel cell, the secondary battery, and the motor are electrically connected to each other; the motor is driven by obtaining electric power from at least one of the fuel cell and the secondary battery, When the fuel cell generates an amount of electric power that exceeds the amount of electric power consumed, the control unit increases the amount of electric power supplied from the fuel cell to the motor, while operating the air resistance increasing device to increase air resistance and maintain a flying state, thereby performing power consumption control; When the fuel cell generates an amount of power that exceeds the amount of power consumed, and the amount of power that exceeds the amount of power consumed is determined as surplus power, the control unit performs the power consumption control when the amount of surplus power exceeds a first threshold, and stops the power consumption control when the amount of surplus power falls below a second threshold; the secondary battery has a role of storing the electric power generated by the fuel cell, the first threshold value is 30% to 70% of the charge allowable energy, the second threshold value is 0 to 30% of the charge allowable energy, the charge allowable amount of electric power is within a range in which the secondary battery is not overcharged; Flying vehicle.

2. the aerodynamic device is a secondary control surface; During the power consumption control, the secondary control surface is opened in both directions to increase air resistance. The flying vehicle according to claim 1.

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