Monitoring device, monitoring method, and program

Abstract

A monitoring device (50) monitors a battery (14) installed in an eVTOL. The monitoring device (50) is provided with an acquisition unit (51) and an output unit (53). The acquisition unit (51) acquires voltage information relating to the battery (14) at the time of flight and information relating to a movement mode of the eVTOL. The output unit (53) uses the voltage information and a threshold value set for each movement mode to output a monitoring result when a predetermined condition relating to an abnormality of the battery (14) is satisfied. The threshold value set for each movement mode is used and hence the abnormality of the battery (14) can be detected early, and the safety of flight can be increased.

Description

Monitoring device, monitoring method, and program CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Patent Application No. 2023-97930 filed in Japan on June 14, 2023, and the contents of the original application are incorporated by reference in their entirety.

[0002] The disclosure in this specification relates to a monitoring device, a monitoring method, and a program.

[0003] Patent Document 1 discloses a method for controlling an electric flying object. The contents of the prior art document are incorporated by reference as explanations of technical elements in this specification.

[0004] Japanese Patent Application Laid-Open No. 2021-172101

[0005] In Patent Document 1, the battery state is monitored, and measures to prevent an abnormality such as a short circuit are taken after the abnormality is detected. In the above-mentioned respects and in other respects not mentioned, further improvements are required in the monitoring device, the monitoring method, and the program.

[0006] One disclosed object is to provide a monitoring device, a monitoring method, and a program that can improve flight safety.

[0007] One aspect of the disclosure is a monitoring device that monitors a battery mounted on an electric flying vehicle, and includes an acquisition unit that acquires battery voltage information during flight and information related to the travel mode of the electric flying vehicle, and an output unit that outputs the monitoring results when predetermined conditions related to battery abnormalities are met using the voltage information and a threshold value set for each travel mode.

[0008] When an electric flying vehicle moves vertically, the battery is required to discharge a large current for a certain period of time. This means that the battery discharge load fluctuates greatly during flight, and the battery voltage also fluctuates drastically. The disclosed monitoring device uses thresholds set for each travel mode, allowing for early detection of battery abnormalities. This improves flight safety.

[0009] Another aspect of the disclosure is a monitoring method executed by a processor to monitor a battery mounted on an electric flying vehicle, which includes acquiring battery voltage information during flight and information regarding the travel mode of the electric flying vehicle, and outputting a monitoring result when a predetermined condition regarding a battery abnormality is met using the voltage information and a threshold value set for each travel mode.

[0010] When an electric flying vehicle moves vertically, the battery is required to discharge a large current for a certain period of time. This means that the battery discharge load fluctuates greatly during flight, and the battery voltage also fluctuates drastically. The disclosed monitoring method uses thresholds set for each movement mode, allowing for early detection of battery abnormalities. This improves flight safety.

[0011] Another aspect of the disclosure is a program stored in a storage medium for monitoring a battery mounted on an electric flying vehicle, the program including instructions to be executed by a processor, the instructions including the instructions to acquire battery voltage information during flight and information regarding the movement mode of the electric flying vehicle, and to output monitoring results when predetermined conditions regarding battery abnormalities are met using the voltage information and thresholds set for each movement mode.

[0012] When an electric flying vehicle moves vertically, the battery is required to discharge a large current for a certain period of time. This means that the battery discharge load fluctuates greatly during flight, and the battery voltage also fluctuates drastically. The disclosed program uses thresholds set for each movement mode, allowing for early detection of battery abnormalities. This improves flight safety.

[0013] The various aspects disclosed in this specification employ different technical means to achieve their respective objectives. The reference numerals in parentheses in the claims are intended to exemplarily indicate the corresponding parts of the embodiments described below, and are not intended to limit the technical scope. The objectives, features, and advantages disclosed in this specification will become more apparent by reference to the following detailed description and the accompanying drawings.

[0014] 4 is a diagram illustrating the configuration of an eVTOL and a ground station. FIG. 5 is a diagram illustrating the functional layout of a traffic management system. FIG. 6 is a plan view showing a battery. FIG. 7 is a cross-sectional view taken along line IV-IV in FIG. 3. FIG. 8 is a diagram illustrating a battery cell. FIG. 9 is a diagram illustrating a power profile. FIG. 10 is a diagram illustrating detection of anomalies when fixed values ​​are used. FIG. 11 is a diagram illustrating an example of a monitoring device. FIG. 12 is a diagram illustrating another example of a monitoring device. FIG. 13 is a diagram illustrating an example of thresholds stored in a memory. FIG. 14 is a diagram illustrating an example of thresholds set by a setting unit. FIG. 15 is a diagram illustrating another example of thresholds set by a setting unit. FIG. 16 is a diagram illustrating an example of a battery pack voltage Vb and a cell voltage Vc. FIG. 17 is a diagram illustrating an example of threshold setting when a voltage change rate is used. FIG. 18 is a diagram illustrating an example of threshold setting when cell voltage variation is used. A flowchart illustrating an example of a control method. A flowchart illustrating another example of a control method. A diagram illustrating delay in battery voltage fluctuations due to normal transient response of battery voltage. A diagram illustrating divergence of voltage change rate due to normal sudden fluctuations in battery voltage. A flowchart illustrating another example of a control method.

[0015] Hereinafter, several embodiments will be described with reference to the drawings. Note that in each embodiment, corresponding components are designated by the same reference numerals, and redundant description may be omitted. When only a portion of the configuration is described in each embodiment, the configuration of another embodiment previously described may be applied to the remaining portion of the configuration. Furthermore, in addition to the combinations of configurations explicitly stated in the description of each embodiment, configurations of several embodiments may be partially combined together even if not explicitly stated, provided that there is no particular problem with the combination.

[0016] The monitoring device, monitoring method, and program described below are applied to an electric flying vehicle. Note that the term "A and / or B" means at least one of A and B. In other words, it may include only A, only B, or both A and B.

[0017] (First embodiment) An electric flying body has a motor (rotating electric machine) as a drive source for movement. An electric flying body is sometimes called an electric airplane, an electric aircraft, or the like. An electric flying body is capable of moving in the vertical direction and the horizontal direction. An electric flying body is capable of moving in a direction having a vertical component and a horizontal component, i.e., in a diagonal direction. Examples of electric flying bodies include electric vertical take-off and landing aircraft (eVTOL), electric short take-off and landing aircraft (eSTOL), and drones. eVTOL is an abbreviation for electronic vertical take-off and landing aircraft. eSTOL is an abbreviation for electronic short distance take-off and landing aircraft.

[0018] The electric air vehicle may be either a manned or unmanned aircraft. In the case of a manned aircraft, the electric air vehicle is operated by a pilot as a pilot. In the case of an unmanned aircraft, the electric air vehicle may be operated by remote control by a pilot or may be automatically controlled by a control system. As an example, the electric air vehicle in this embodiment is an eVTOL.

[0019] <eVTOL> Fig. 1 shows an eVTOL and a ground station. As shown in Fig. 1, an eVTOL 10 includes an airframe 11, fixed wings 12, rotors 13, a battery 14, an EPU 15, a BMS 16, and the like.

[0020] The aircraft main body 11 is the fuselage of the aircraft. The aircraft main body 11 has a shape that extends in the front-to-rear direction. The aircraft main body 11 has a passenger compartment for passengers and / or a luggage compartment for carrying luggage.

[0021] The fixed wing 12 is a wing portion of the aircraft and is connected to the aircraft body 11. The fixed wing 12 provides gliding lift. The gliding lift is the lift generated by the fixed wing 12. The fixed wing 12 may have a main wing 121 and a tail 122. The main wing 121 extends left and right from near the center of the aircraft body 11 in the fore-and-aft direction. The tail 122 extends left and right from the rear of the aircraft body 11. The shape of the fixed wing 12 is not particularly limited. For example, a swept wing, a delta wing, a straight wing, etc. may be used.

[0022] A plurality of rotors 13 are provided on the airframe. At least some of the plurality of rotors 13 may be provided on the fixed wing 12. At least some of the plurality of rotors 13 may be provided on the airframe main body 11. The number of rotors 13 provided on the eVTOL 10 is not particularly limited. A plurality of rotors 13 may be provided on each of the airframe main body 11 and the main wing 121.

[0023] The rotor 13 may be referred to as a rotor, a propeller, a fan, etc. The rotor 13 may have blades 131 and a shaft 132. The blades 131 are attached to the shaft 132. The blades 131 are vanes that rotate together with the shaft 132. A plurality of blades 131 extend radially around the axis of the shaft 132. The shaft 132 is the rotation axis of the rotor 13 and is driven to rotate by a motor of the EPU 15.

[0024] The rotor 13 generates a thrust force by rotation. The thrust force acts on the eVTOL 10 mainly as rotational lift during takeoff and landing operations of the eVTOL 10. The rotor 13 mainly provides rotational lift during takeoff and landing operations. Rotational lift is lift generated by the rotation of the rotor 13. During takeoff and landing operations, the rotor 13 may provide only rotational lift, or may provide forward thrust in addition to rotational lift. The rotor 13 provides rotational lift when the eVTOL 10 is hovering.

[0025] The propulsive force acts primarily as thrust on the eVTOL 10 during cruise operation of the eVTOL 10. The rotor 13 primarily provides thrust during cruise operation. During cruise operation, the rotor 13 may provide thrust alone or may provide lift in addition to thrust.

[0026] The battery (BAT) 14 is a device for driving the rotor 13 to rotate. The battery 14 is sometimes referred to as a battery pack. The battery 14 is capable of storing DC power and includes rechargeable battery cells. The battery 14 includes at least one assembled battery including multiple battery cells. The battery cells are secondary batteries that generate electromotive force through a chemical reaction. Examples of the battery cells include lithium-ion secondary batteries and nickel-metal hydride secondary batteries. The battery cells may be secondary batteries with a liquid electrolyte or so-called all-solid-state batteries with a solid electrolyte. The battery cells may be configured such that the battery reaction occurs when ions (electrolytes) that contribute to the battery reaction move between positive and negative electrodes via an electrolytic solution and / or solid electrolyte. In addition to the battery 14, the eVTOL 10 may also include a fuel cell, a generator, or the like as a power source for supplying power to the device. The battery 14 supplies power to the EPU 15. The battery 14 may supply power to auxiliary equipment (not shown) such as an air conditioner, an ECU 20 (described later), a lift adjustment mechanism (not shown), and the like.

[0027] The battery 14 of the eVTOL 10 is required to have high capacity and high output performance. For this reason, a battery cell that can provide both high capacity and high output is desirable. From the standpoint of output, a battery cell with low resistance over a wide SOC range is desirable. In particular, a battery cell with low resistance and high output even in a low SOC range is desirable. SOC is an abbreviation for State Of Charge.

[0028] Positive electrode materials for battery cells can include, for example, LCO, NMC, NCA, LFP, and LMFP. LCO is lithium cobalt oxide (LiCoO2). NMC is lithium nickel cobalt manganese oxide (Li(NiMnCo)O2). NCA is lithium nickel cobalt aluminate (Li(NiCoAl)O2). LFP is lithium iron phosphate (LiFePO4). LMFP is lithium manganese iron phosphate (LiFexMnyPO4). LCO, NMC, and NCA are layered compounds. In particular, a positive electrode made of LMFP or a blend of LMFP and NMC is preferred, as they have low resistance in the low SOC region.

[0029] The negative electrode material for the battery cell can be, for example, a carbon-based material such as hard carbon or soft carbon, a silicon-based material, a lithium-based material, or a titanium-based material such as LTO or NTO. LTO is lithium titanate (Li4Ti5O12). NTO is niobium titanium oxide (TiNb2O7). In particular, carbon-based and titanium-based negative electrodes are preferred because of their low resistance in the low SOC region.

[0030] The EPU 15 rotates and drives the rotors 13, which provide propulsive force to the eVTOL 10. The EPU 15 is a device for rotating and driving the rotors 13. EPU is an abbreviation for Electric Propulsion Unit. The EPU 15 corresponds to an electric propulsion device. The EPU 15 includes a motor. The EPU 15 may also include an inverter and an ESC in addition to the motor. ESC is an abbreviation for Electronic Speed ​​Controller. The number of EPUs 15 may be the same as the number of rotors 13. For example, the eVTOL 10 may include six EPUs 15. Each EPU 15 and each rotor 13 are connected one-to-one. Alternatively, two or more rotors 13 may be connected to one EPU 15 via a gearbox.

[0031] The BMS 16 monitors the status of the unit batteries that make up the battery 14. BMS is an abbreviation for Battery Management System. The BMS 16 can monitor the voltage, current, temperature, internal resistance, SOC, SOH, and other safety-related conditions of the battery 14, such as internal pressure and gas leakage. SOH is an abbreviation for State Of Health. The BMS 16 may be provided integrally with the battery 14. The BMS 16 may be provided separately from the battery 14. A part of the BMS 16 may be provided inside the battery 14, and another part may be provided outside the battery 14.

[0032] The BMS 16 may be provided individually for each battery pack. One BMS 16 may be provided for multiple battery packs. One BMS 16 may be provided for all battery packs. When multiple BMSs 16 are provided, a function for controlling all BMSs 16 may be provided separately from the BMS 16, or may be provided integrally with the BMS 16.

[0033] The eVTOL 10 further includes an ECU 20 and auxiliary equipment (not shown). ECU is an abbreviation for Electronic Control Unit. The eVTOL 10 may also include a lift adjustment mechanism (not shown). The lift adjustment mechanism adjusts the gliding lift of the fixed wing 12. The lift adjustment mechanism increases or decreases the gliding lift generated by the fixed wing 12. The eVTOL 10 may also include, for example, a tilt mechanism or a flap as the lift adjustment mechanism. The tilt mechanism is driven to adjust the tilt angle of the rotor 13. The flap is a movable wing piece provided on the fixed wing 12.

[0034] <Traffic Traffic Management System> The Traffic Management System is a system for formulating flight plans, monitoring flight status, collecting and managing flight information, and supporting flight operations. At least some of the functions of the Traffic Management System may be located in the onboard computer of the eVTOL 10. At least some of the functions of the Traffic Management System may be located in an external computer capable of wireless communication with the eVTOL 10. The external computer may be the server 31 of the ground station 30 as shown in FIG. 1. The ground station 30 is capable of wireless communication with the eVTOL 10. The ground stations 30 are capable of wireless communication with each other.

[0035] As an example, in this embodiment, some of the functions of the traffic management system are allocated to the ECU 20 of the eVTOL 10, and some of the functions of the traffic management system are allocated to the server 31 of the ground station 30. The functions of the traffic management system are shared between the ECU 20 and the server 31.

[0036] As shown in FIG. 1 , the ECU 20 is configured to include a processor (PC) 201, a memory (MM) 202, a storage (ST) 203, and a communication circuit (CC) 204 for wireless communication. The processor 201 executes various processes by accessing the memory 202. The memory 202 is a rewritable volatile storage medium. The memory 202 is, for example, a RAM. RAM is an abbreviation for Random Access Memory. The storage 203 is a rewritable non-volatile storage medium. The storage 203 stores a program (PG) 203P executed by the processor 201. The program 203P configures multiple functional units by causing the processor 201 to execute multiple instructions. The ECU 20 may include multiple processors 201.

[0037] Like the ECU 20, the server 31 is configured to include a processor (PC) 311, a memory (MM) 312, a storage (ST) 313, a communication circuit (CC) 314, and the like. The processor 311 executes various processes by accessing the memory 312. The memory 312 is a rewritable volatile storage medium, such as a RAM. The storage 313 is a rewritable non-volatile storage medium. The storage 313 stores a program (PG) 313P to be executed by the processor 311. The program 313P configures multiple functional units by causing the processor 311 to execute multiple instructions. The server 31 may include multiple processors 311.

[0038] FIG. 2 shows an example of the functional layout of the traffic management system. The traffic management system 40 shown in FIG. 2 has an external management unit 41 and an internal management unit 42. The external management unit 41 is functionally arranged in the server 31 of the ground station 30. The internal management unit 42 is functionally arranged in the ECU 20 of the eVTOL 10. In this way, some of the functions of the traffic management system 40 may be arranged in the server 31, and other parts of the functions may be arranged in the ECU 20. The external management unit 41 and the internal management unit 42 can communicate with each other wirelessly. The internal management unit 42 can communicate with various devices arranged in the eVTOL 10 via wired or wireless communication.

[0039] <Battery> Fig. 3 shows an example of a battery 14. Fig. 4 is a cross-sectional view taken along line IV-IV in Fig. 3. Fig. 4 shows a simplified configuration of the battery cell. Fig. 5 is a diagram showing the arrangement of the electrode terminals. In the following, the height direction of each battery cell is referred to as the Z direction, a direction perpendicular to the Z direction is referred to as the Y direction, and a direction perpendicular to both the Z direction and the Y direction is referred to as the X direction. For convenience, the entire battery cell is shown in Fig. 4 with metallic hatching.

[0040] As shown in Figures 3 and 4, the battery 14 includes at least one assembled battery 141. The assembled battery 141 is configured to include a plurality of battery cells 142. The plurality of battery cells 142 may have a common structure, or some of the structures may be different from the others. There are no particular limitations on the number or arrangement of the plurality of battery cells 142. The plurality of battery cells 142 may be connected in series, or may be connected in parallel and in series.

[0041] The battery cell 142 has a power generating element and a battery case that houses the power generating element. The battery case provides the outer shell of the battery cell 142. The battery case may be formed, for example, using a metal material or a laminate film. The shape of the battery cell 142, i.e., the battery case, is not particularly limited. It may be rectangular, laminated, or cylindrical.

[0042] Each battery cell 142 has electrode terminals 142P and 142N. As shown in FIG. 5 , the electrode terminals 142P and 142N may be provided on a common surface or on different surfaces. For example, they may be provided on one surface and the opposite surface. The electrode terminals 142P and 142N may protrude from the corresponding surface. The electrode terminal 142P is electrically connected to the positive electrode of the battery cell 142. The electrode terminal 142P may be referred to as a positive terminal, P terminal, etc. The electrode terminal 142N is electrically connected to the negative electrode of the battery cell 142. The electrode terminal 142N may be referred to as a negative terminal, N terminal, etc. The electrode terminals may also be referred to as battery cell terminals, current collecting tabs, etc.

[0043] The battery cell 142 shown in Figures 3 and 4 has a rectangular shape, specifically a flat shape that is thin in the Y direction. The multiple battery cells 142 are arranged side by side in the Y direction. The electrode terminals 142P and 142N are provided on one of the end faces in the Z direction, i.e., on a common surface. The multiple battery cells 142 are arranged such that the electrode terminals 142P and the electrode terminals 142N are positioned alternately in the Y direction. The electrode terminals 142P and the electrode terminals 142N of adjacent battery cells 142 are electrically connected by a bus bar (not shown).

[0044] The battery pack 141 may include a plurality of battery cells 142 arranged in the Y direction. The arrangement of the battery cells 142 is not limited to the arrangement described above. For example, in the case of cylindrical battery cells 142, they may be arranged in a staggered pattern when viewed from the Z direction.

[0045] <Power Profile> Figure 6 shows the power profile of the eVTOL 10 from takeoff to landing. Note that the power profiles of electric flying vehicles other than the eVTOL 10 are similar to those of the eVTOL 10. Period P1 is referred to as takeoff, takeoff flight, takeoff operation, etc. Period P2 is referred to as cruising, cruising flight, cruising operation, etc. Period P3 is referred to as landing, landing flight, landing operation, etc. Periods P1 and P3 are referred to as takeoff and landing, takeoff and landing flight, takeoff and landing operation, etc. For convenience, in Figure 6, the required power, i.e., output, is constant throughout almost the entire range of each of periods P1 and P3.

[0046] The eVTOL 10 ascends from the takeoff point to the cruise start point during period P1. The eVTOL 10 cruises at a predetermined altitude during period P2. The eVTOL 10 descends from the end point of period P2 to the landing point during period P3. The movement of the eVTOL 10 includes a primarily horizontal component during period P2 and a primarily vertical component during periods P1 and P3. During periods P1 and P3 when the eVTOL 10 moves vertically, high output is required to drive the rotor 13 for a predetermined continuous period of time.

[0047] Thus, a high output load is applied to the battery 14 during vertical movement. The greatest output is required during takeoff and landing. The output of the battery 14 varies greatly between vertical movement and horizontal movement. The output of the battery 14 varies greatly between takeoff and landing and cruising.

[0048] <Battery Voltage> Fig. 7 is a diagram showing abnormality detection when a fixed threshold is used, in which the change in battery voltage during flight is shown by a solid line.

[0049] As described above, during vertical movement, particularly during takeoff and landing, the battery 14 that drives the EPU 15 is required to discharge at a large current for a predetermined period of time. For example, during takeoff and landing, the battery 14 discharges continuously (continuously) at a maximum discharge rate of approximately 3 C to approximately 15 C for approximately 30 to approximately 90 seconds.

[0050] The discharge rate indicates the relative ratio of the current during discharge to the battery capacity, and is expressed in units of C. A discharge rate of 1C indicates the current value at which a cell with a nominal capacity is discharged at a constant current until discharge is complete in one hour. The maximum discharge rate during cruising of an electric aircraft or an electric vehicle (BEV) is approximately 1C to 2C. In the case of a BEV, this is a level at which the maximum discharge rate continues for approximately 5 to 10 seconds. BEV is an abbreviation for Battery Electric Vehicle. As such, there is a large variation in discharge characteristics between takeoff and landing and cruising.

[0051] Monitoring battery voltage, which is sensitive to internal short circuits and rapid deterioration that can cause thermal runaway in the battery 14, is used as a means of early detection of abnormalities. However, the discharge load of the battery 14 fluctuates greatly during flight, and the battery voltage also fluctuates sharply, as shown by the solid line in Figure 7. For this reason, it is difficult to detect abnormalities early using management that uses a fixed value (constant value) as the threshold value.

[0052] For example, if an abnormality occurs at time t1 during cruising and the voltage drops as indicated by the dashed arrow, the abnormality can be detected at time t2 by using a relatively high fixed value 1. Although the abnormality can be detected early in this way, the high value of fixed value 1 can lead to erroneous determinations during takeoff and landing. On the other hand, by using fixed value 2, which is lower than fixed value 1 but higher than the lower limit of the battery 14's tolerance, it is possible to avoid erroneous determinations during takeoff and landing. However, the abnormality will be detected at time t3, which is later than time t2. In other words, the abnormality cannot be detected early.

[0053] <Monitoring Device> Fig. 8 shows an example of a monitoring device. Fig. 9 shows another example of a monitoring device. As shown in Fig. 8, the monitoring device 50 may include an acquisition unit 51, a determination unit 52, and an output unit 53. As shown in Fig. 9, the monitoring device 50 may further include a setting unit 54.

[0054] The monitoring device 50 monitors the battery 14. The functional layout of the monitoring device 50 is not particularly limited. At least some of the functions of the monitoring device 50 may be located on board or outside the aircraft. The functions of the monitoring device 50 may be distributed across multiple devices on board. The functions of the monitoring device 50 may be distributed across multiple devices outside the aircraft. Some of the functions of the monitoring device 50 may be located on board, and other parts of the functions may be located outside the aircraft.

[0055] For example, at least some of the functions of the monitoring device 50 may be arranged in the BMS 16. At least some of the functions of the monitoring device 50 may be arranged in the ECU 20. At least some of the functions of the monitoring device 50 may be arranged in the server 31 of the ground station 30. At least some of the functions of the monitoring device 50 may be arranged in the traffic management system 40. At least some of the functions of the monitoring device 50 may be arranged in the on-board management unit 42. At least some of the functions of the monitoring device 50 may be arranged in the off-board management unit 41.

[0056] The acquisition unit 51 acquires information regarding the voltage of the battery 14 during flight and information regarding the travel mode of the eVTOL 10. The information regarding the voltage of the battery 14 during flight may be referred to as battery voltage information or voltage information. The information regarding the travel mode may be referred to as travel mode information.

[0057] The acquisition unit 51 may acquire information such as voltage information and travel mode information from the BMS 16, the traffic management system 40, the EPU 15, etc. The acquisition unit 51 may acquire actual measured values, intermediate calculated values, or calculated values ​​such as feature quantities as information. The acquisition unit 51 may acquire information by performing calculations within the monitoring device 50 based on the actual measured values ​​and intermediate calculated values ​​acquired from the BMS 16, etc. The acquisition unit 51 acquires information via wireless communication and / or wired communication.

[0058] For example, the resistance of the battery 14 changes depending on the environmental temperature. The battery voltage is affected by the fluctuations in the battery resistance. In other words, the battery voltage is affected by the environmental temperature, etc. Therefore, the acquisition unit 51 may acquire environmental information in addition to the voltage information and the travel mode information. The environmental information may include, for example, the temperature, wind speed, and wind direction. Taking into account the fluctuations in the environmental parameters, the accuracy of abnormality determination can be improved.

[0059] The eVTOL 10 can assume multiple movement modes during flight. The movement modes may include a mode in which the vehicle moves primarily vertically and a mode in which the vehicle moves primarily horizontally. In addition to the vertical and horizontal movement modes, a mode in which the vehicle moves diagonally may be included. The eVTOL 10 moves primarily vertically during takeoff and landing, and primarily horizontally during cruising. Thus, the movement modes may include a takeoff and landing mode and a cruising mode. The movement modes may include a takeoff mode, a cruising mode, and a landing mode. The cruising mode may be subdivided to take into account cases in which the vehicle temporarily moves vertically during cruising.

[0060] The acquisition unit 51 may acquire, as the travel mode information, information indicating the travel mode itself, or may acquire information for determining the travel mode. The acquisition unit 51 may acquire, as the travel mode information, discharge characteristic information and / or flight information. The acquisition unit 51 may have a function for determining the travel mode based on the acquired discharge characteristic information and / or flight information. The monitoring device 50 may include a functional unit separate from the acquisition unit 51 that determines the travel mode based on the information acquired by the acquisition unit 51. The discharge characteristic information is information related to the discharge current. For example, if the discharge current is equal to or greater than a predetermined threshold, it may be determined to be a vertical travel mode, and if the discharge current is less than the threshold, it may be determined to be a horizontal travel mode.

[0061] The flight information may be a signal indicating the travel mode obtained from the traffic management system 40 or the like. The flight information may also be altitude change information such as the ascent speed or descent speed of the eVTOL 10. For example, if the ascent speed is equal to or greater than a predetermined threshold, it may be determined to be a vertical travel mode, and if it is less than the threshold, it may be determined to be a horizontal travel mode. The flight information may also be information indicating the orientation of the rotor 13. If the orientation of the rotor 13 is variable depending on the travel mode using a tilt mechanism or the like, the travel mode can be determined based on information about the orientation of the rotor 13. The flight information may also be time information for the flight. If the flight is precisely time-managed, the travel mode may be determined based on time. In the case of repeated travel between spots, the flight is precisely time-managed. Flight is particularly precisely time-managed in the case of automated flight.

[0062] The acquisition unit 51 may acquire information on the battery state together with the discharge characteristic information as the travel mode information. The battery state information is the open circuit voltage (OCV) and / or resistance. OCV is an abbreviation for Open Circuit Voltage. Instead of the OCV, the SOC may be acquired. SOC is an abbreviation for State Of Charge.

[0063] The determination unit 52 has a function of comparing the voltage information acquired by the acquisition unit 51 with a threshold value set for each travel mode to determine whether or not a battery abnormality exists. The threshold value may be set to a different value for each travel mode. The determination unit 52 functions as a detection unit that detects a battery abnormality. The determination unit 52 may have a function of determining whether or not abnormality detection is being performed normally based on the voltage information. The determination unit 52 may also function as a diagnosis unit that diagnoses (determines) whether or not the abnormality detection function is normal. The monitoring device 50 may include a diagnosis unit separate from the determination unit 52. The monitoring device 50 may also include a diagnosis unit separate from the detection unit. The determination unit 52 may have a function of limiting abnormality detection and threshold values ​​for a predetermined period of time. The determination unit 52 may also function as a limiting unit that limits abnormality detection and threshold values. The monitoring device 50 may also include a limiting unit separate from the determination unit 52 (detection unit).

[0064] The output unit 53 outputs the abnormality determination result to the outside of the monitoring device 50. The output unit 53 outputs the monitoring result when a predetermined condition related to an abnormality in the battery 14 is satisfied. The output unit 53 may output the determination result, for example, to issue an alarm to the crew or the ground station 30. The output unit 53 may output the determination result to trigger a transition to avoidance operation. The output unit 53 may output the determination result to the traffic management system 40 that displays the operational status of the aircraft and controls operation. The monitoring device 50 itself may display the result. The output unit 53 may output a control request for avoidance operation to a control device that controls flight. The control device may be provided integrally as a function of the traffic management system 40, or may be provided separately.

[0065] The output unit 53 may output in multiple stages, such as issuing an alarm in a first stage and taking evasive action in a second stage or later. As the evasive action, for example, redundant operation of the battery 14 may be adopted, or an emergency landing action may be adopted. The redundant operation of the battery 14 may, for example, stop the output of the system with an abnormality and continue the flight using the remaining system. As the evasive action, multiple actions may be executed simultaneously. The evasive action may be capable of being performed in stages. The output unit 53 may estimate the time until an abnormality occurs based on the time series transition of the target information, and output the estimate as urgency information.

[0066] The setting unit 54 sets a threshold value to be compared with the voltage information based on the travel mode information acquired by the acquisition unit 51. The setting unit 54 sets a threshold value for each travel mode. The setting unit 54 may set the threshold value to a different value for each travel mode. The setting unit 54 may set the threshold value based on the discharge characteristic information and battery state information, which are travel mode information.

[0067] <Thresholds> The thresholds are set individually for each travel mode. The thresholds are set according to the travel mode. The thresholds may be associated with the travel mode and stored in advance in memory. The determination unit 52 reads out the thresholds according to the travel mode from the memory and uses them for determination. FIG. 10 shows an example of thresholds stored in the memory. The travel modes include two types: takeoff and landing mode and cruising mode. The memory stores a threshold Th1 corresponding to the takeoff and landing mode and a threshold Th2 corresponding to the cruising mode. The determination unit 52 makes a determination using the threshold Th1 in the takeoff and landing mode and makes a determination using the threshold Th2 in the cruising mode. The threshold Th1 is set to a value lower than the threshold Th2 and higher than the allowable lower limit.

[0068] The threshold value may be set by deriving normal voltage behavior during flight using, for example, prior experiments or battery simulations, and providing a predetermined margin for the voltage behavior. The margin may be, for example, a margin for variations in battery discharge characteristics, fluctuations in OCV or battery resistance, errors in the detection system, etc. Threshold values ​​may be prepared for each flight plan, such as for differences in flight route.

[0069] The threshold may be set by the setting unit 54 according to the travel mode. The setting unit 54 may set the threshold based on the discharge characteristic information and battery state information acquired by the acquisition unit 51. Fig. 11 shows an example of the threshold set by the setting unit 54. Fig. 12 shows another example of the threshold set by the setting unit 54. In Figs. 11 and 12, the travel mode includes three types: takeoff mode, cruising mode, and landing mode. The setting unit 54 sets a threshold Th11 corresponding to the takeoff mode, a threshold Th12 corresponding to the cruising mode, and a threshold Th13 corresponding to the landing mode.

[0070] The relationship shown in Equation 1 holds between the battery voltage during discharge, the discharge characteristics (discharge current), and the battery state (OCV, battery resistance). Therefore, if the discharge characteristic information and the battery state are reflected in the threshold setting, it becomes possible to detect abnormalities earlier and with higher accuracy. Battery voltage during discharge = OCV - discharge current x battery resistance (Equation 1) The OCV decreases as the SOC decreases. It is advisable to create an SOC-OCV map in advance and calculate the OCV from the SOC value. During landing, the SOC decreases compared to during takeoff. For this reason, as shown in FIG. 11, it is advisable to set the threshold Th13 set during landing lower than the threshold Th11 set during takeoff.

[0071] The resistance of the battery 14 also changes with the SOC. The behavior of the resistance can be determined in advance through experiments or the like, and then calculated using a map model or regression model. Many battery cells 142 tend to have increased resistance in the low SOC range. The setting unit 54 can preferably reflect the resistance in the threshold setting, particularly for flights using the low SOC range.

[0072] The setting unit 54 may set the threshold value using information updated before flight by a battery status diagnosis performed while the aircraft is parked between flights. The battery status diagnosis may include an AC impedance diagnosis. Parameters of a battery equivalent circuit model and a battery reaction model, such as DC resistance, battery reaction resistance, and diffusion resistance, can be calculated. This allows for a simulation of voltage fluctuations during discharge (during flight) immediately before flight, resulting in higher accuracy.

[0073] The setting unit 54 may successively change the set threshold value based on changes in the battery state during flight. As shown in FIG. 12 , the setting unit 54 may successively change the threshold value in accordance with fluctuations in battery voltage. This enables earlier and more accurate detection of abnormalities. The setting unit 54 may set the threshold value based on an operation plan when planning an operation. The setting unit 54 may set the threshold value according to actual results during flight. The threshold value based on the plan may be updated according to the actual results.

[0074] The setting unit 54 may use, as the battery state information, information on an increase in resistance caused by a concentration imbalance of ions that contribute to the battery reaction. When the battery 14 is discharged, a temporary imbalance occurs in the concentration distribution of ions that contribute to the battery reaction. The concentration imbalance occurs in the electrolyte or electrodes. When the concentration imbalance occurs, the internal resistance of the battery 14 temporarily (reversibly) increases. As a result, even if the SOC of the battery 14 is sufficient, the output performance of the battery 14 decreases. In this way, temporary (reversible) degradation occurs in the battery 14. The temporary degradation is sometimes referred to as high-rate degradation.

[0075] The greater the concentration imbalance, the greater the degree of primary degradation. Electric flying vehicles, particularly eVTOL 10, require high output during takeoff and landing. Continuous output is also required during flight. Therefore, the degree of primary degradation is likely to increase. The setting unit 54 predicts the degree of primary degradation and reflects this in the threshold, enabling earlier and more accurate abnormality detection. The setting unit 54 may also predict primary degradation in advance and reflect this in the threshold.

[0076] The setting unit 54 may acquire information regarding the degree of temporary deterioration of the battery 14, or may calculate the degree of temporary deterioration based on the acquired information. The degree of temporary deterioration is the difference from a reference value of the internal resistance. The reference value may be, for example, the initial internal resistance value before takeoff for the current flight. The reference value may be the internal resistance value after processing to resolve the temporary deterioration, or the internal resistance value after charging on the ground. The reference value is preferably the internal resistance value after the temporary deterioration has been sufficiently resolved. The calculation of the degree of temporary deterioration may be an actual measurement calculation based on an actual measurement value, or a predictive calculation based on a predictive value. The calculated value may be the degree of temporary deterioration at the time of monitoring, or the degree of temporary deterioration at the time of takeoff or landing.

[0077] The setting unit 54 may predict the degree of primary deterioration in advance and reflect the prediction in the threshold value. The setting unit 54 may predict the degree of primary deterioration in advance by calculating a fluctuation profile of primary deterioration based on a discharge profile planned for the flight. The setting unit 54 may predict the degree of primary deterioration based on, for example, a prediction map or a prediction model such as multiple regression. The degree of primary deterioration may be predicted based on a prediction model generated using machine learning.

[0078] The setting unit 54 may predict the degree of temporary deterioration in advance by calculating a fluctuation profile of the temporary deterioration using past history data. The history data may be information on the degree of past temporary deterioration for which the takeoff point and / or landing point and aircraft type match the target flight. Because the eVTOL 10 flight plan is finite and repeats frequently, history information can be utilized. Furthermore, by utilizing history information for takeoff and landing points, which are prone to prediction errors, the prediction accuracy of the degree of temporary deterioration can be improved. The ease of operation, output characteristics, and the like vary depending on the model (type) of the eVTOL 10. This can further improve the prediction accuracy of the degree of temporary deterioration.

[0079] The setting unit 54 may set the threshold value according to the degree of increase (actual result) of temporary deterioration during flight. The setting unit 54 may update the prediction-based threshold value according to the actual result. The setting unit 54 may calculate the degree of temporary deterioration based on the output history of the battery. The setting unit 54 may calculate the integrated value of the discharge current during flight as the degree of temporary deterioration. When charging is performed, the integrated value of the charge / discharge current may be used as the degree of temporary deterioration. Output stoppage during standby on the ground or temporary output stoppage during flight also acts to eliminate concentration imbalances caused by discharge to some extent. Therefore, the integrated current value may be corrected in a direction that eliminates the concentration imbalance.

[0080] Note that the larger the current (higher output) or the longer the duration of output, the more likely concentration bias is to occur. Therefore, when using the integrated current value, the current value and / or duration may be weighted during integration. The weighting coefficient may be calculated using a map or regression model created in advance from experimental data, etc.

[0081] The setting unit 54 may calculate the degree of temporary deterioration using a battery physics model. The battery physics model models electrochemical reactions and material transport and is capable of analyzing concentration distribution. By inputting a current history into this battery physics model and performing calculations, it is possible to estimate the concentration bias of ions in the electrolyte and electrodes that contribute to the battery reaction.

[0082] The setting unit 54 may calculate the degree of temporary degradation based on the battery resistance. The setting unit 54 may also calculate the increase (change) in the internal resistance, i.e., the degree of temporary degradation itself. The change becomes a decrease when the temporary degradation is resolved. The increase in resistance of the battery 14 can be calculated using time-series values ​​of the internal resistance calculated from the voltage, current, etc. of the battery 14.

[0083] The setting unit 54 may calculate the degree of temporary deterioration using an estimated resistance obtained by a battery model. The battery model is, for example, a battery equivalent circuit model. The estimated resistance is calculated from an estimated current estimated from a battery model that assumes a uniform concentration distribution and an actually measured voltage. The degree of temporary deterioration can be calculated from the difference between the estimated resistance and the measured resistance calculated from the actually measured current and voltage.

[0084] The setting unit 54 may calculate the degree of temporary deterioration based on the resistance component of the AC impedance. The increase (change) in the resistance component of the AC impedance of the battery 14 can be used as the degree of temporary deterioration. In particular, it is preferable to use the increase in the resistance component in the high frequency range of the AC impedance as the degree of temporary deterioration. This makes it possible to more accurately calculate the degree of concentration imbalance in the electrolyte, which is the main cause of imbalance.

[0085] The setting unit 54 may calculate the degree of temporary deterioration based on historical information of past flights. The historical information may include information on the degree of past temporary deterioration for aircraft types that match the takeoff and / or landing points of the target flight. Because the eVTOL 10 flight plan is finite and repeats frequently, historical information can be utilized. Furthermore, utilizing historical information for takeoff and landing points, which are prone to prediction errors, can improve the accuracy of predicting the degree of temporary deterioration. The ease of operation, output characteristics, and other factors vary depending on the model (type) of the eVTOL 10. This can further improve the accuracy of predicting the degree of temporary deterioration.

[0086] <Voltage Information> Fig. 13 shows the battery pack voltage Vb and cell voltage Vc. Fig. 14 shows an example of threshold setting when using the voltage change rate. Fig. 15 shows an example of threshold setting when using the cell voltage variation. In Fig. 14, the threshold for takeoff and landing mode is set to Th21, and the threshold for cruising mode is set to Th22. In Fig. 15, the threshold for takeoff and landing mode is set to Th31, and the threshold for cruising mode is set to Th32.

[0087] 7, when the voltage drops due to an abnormality in the battery 14, the absolute value decreases, the voltage change rate increases, and the variation between cells increases. The voltage change rate is sometimes referred to as the voltage change speed.

[0088] The acquisition unit 51 may acquire, as the battery information, the absolute value of the battery pack voltage Vb shown in FIG. 13 . The acquisition unit 51 may acquire the absolute value of each cell voltage Vc. The acquisition unit 51 may acquire, as the battery information, the voltage change rate as shown in FIG. 14 . The voltage change rate may be the change rate of the battery pack voltage Vb or the change rate of the cell voltage Vc. The acquisition unit 51 may acquire, as the battery information, the variation in the cell voltage Vc as shown in FIG. 15 .

[0089] The acquisition unit 51 may acquire at least one of the following battery information: absolute value of the battery pack voltage Vb, absolute value of each cell voltage Vc, rate of change of the battery pack voltage Vb, rate of change of the cell voltage Vc, and variation of the cell voltage Vc. By monitoring multiple parameters such as absolute value, rate of change, and variation, it becomes possible to detect abnormalities in the battery 14 with higher accuracy.

[0090] <Monitoring Method> As described above, monitoring device 50 may be disposed in ECU 20 of eVTOL 10. In this case, the execution of processing of each functional block of monitoring device 50 by processor 201 corresponds to the execution of the monitoring method. The monitoring device may be disposed in server 31 of ground station 30. In this case, the execution of processing of each functional block of monitoring device 50 by processor 311 corresponds to the execution of the monitoring method.

[0091] As a monitoring method, for example, the method shown in FIG. 16 may be used. The monitoring device 50 (for example, the processor 201) repeatedly executes the process shown in FIG. 16 at a predetermined cycle. First, the monitoring device 50 acquires information (step S10). The monitoring device 50 acquires travel mode information and voltage information of the battery 14. The monitoring device 50 may acquire the flight information described above as the travel mode information. The monitoring device 50 may acquire discharge characteristic information of the battery 14 as the travel mode information. The monitoring device 50 may acquire flight information and discharge characteristic information as the travel mode information. The monitoring device 50 may acquire discharge characteristic information and battery status information as the travel mode information. The monitoring device 50 may acquire flight information, discharge characteristic information, and battery status information as the travel mode information.

[0092] Next, the monitoring device 50 sets a threshold value for each travel mode individually (step S20). The monitoring device 50 may read a threshold value corresponding to the travel mode from memory and set the threshold value. The monitoring device 50 may set the threshold value by calculation or the like based on travel mode information. The monitoring device 50 may set the threshold value based on discharge characteristic information and battery state information.

[0093] Next, the monitoring device 50 compares the acquired voltage information with a threshold value and determines whether the voltage information is outside the allowable threshold range (step S30). For example, the monitoring device 50 may determine that the voltage information is outside the allowable threshold range if the absolute value of the battery pack voltage Vb is less than the threshold value, and may determine that the voltage information is within the allowable threshold range if the absolute value of the battery pack voltage Vb is equal to or greater than the threshold value. The monitoring device 50 may determine that the voltage information is outside the allowable threshold range if the absolute value of the cell voltage Vc is less than the threshold value, and may determine that the voltage information is within the allowable threshold range if the absolute value of the cell voltage Vc is equal to or greater than the threshold value. The monitoring device 50 may determine that the voltage information is outside the allowable threshold range if the rate of change of the battery pack voltage Vb is greater than the threshold value, and may determine that the voltage information is within the allowable threshold range if the rate of change of the cell voltage Vc is equal to or less than the threshold value. The monitoring device 50 may determine that the voltage information is outside the allowable threshold range if the rate of change of the cell voltage Vc ...

[0094] If the voltage information is outside the allowable threshold range, the monitoring device 50 determines that an abnormality has occurred in the battery 14, outputs an abnormality presence signal (step S40), and ends the series of processes. If the voltage information is within the allowable threshold range, the monitoring device 50 does not execute the process of step S40 and ends the series of processes.

[0095] The monitoring method may be the method shown in Fig. 17. First, the monitoring device 50 executes the process of step S10, similar to the method shown in Fig. 16. Next, the monitoring device 50 determines whether or not it is outside of a predetermined period during transition (step S15). The monitoring device 50 determines whether or not it is outside of a predetermined period during transition between vertical movement and horizontal movement.

[0096] The equivalent circuit of the battery 14 includes a capacitor component connected in parallel with a resistor. Therefore, as shown in FIG. 18, fluctuations in battery voltage cause a transient response corresponding to the capacitor component. For example, a transient response occurs when switching from takeoff to cruising. Furthermore, the battery voltage fluctuates rapidly when transitioning (switching) between vertical and horizontal movement. Therefore, as shown in FIG. 19, divergence in the voltage change rate occurs during the transition. Furthermore, delays in signal propagation in the circuit can cause delays in threshold switching.

[0097] As described above, when the movement transitions between the vertical direction and the horizontal direction, there may be a normal sudden change in the voltage information, a delay in the change in the battery voltage due to a normal transient response, and a delay in switching the threshold value, which may lead to an erroneous determination.

[0098] In the example shown in Figure 17, in order to prevent the above-mentioned erroneous determination, it is determined whether the timing corresponds to the timing at which the above-mentioned sudden voltage fluctuation, delay in voltage fluctuation, and delay in threshold switching may occur, i.e., whether it corresponds to a predetermined period during the transition. The predetermined period is at least a part of the period during the transition. The predetermined period may be set based on the derived periods, for example, derived using prior experiments or battery simulations, of the period of normal sudden fluctuation in voltage information during the transition, the delay period in battery voltage fluctuation due to normal transient response, and the delay period in threshold switching. The predetermined period may also be set with a predetermined margin for the derived periods.

[0099] If the monitoring device 50 determines in step S15 that the period is outside the predetermined period, it executes the processing from step S20 onward, similar to the method shown in FIG. 16 . On the other hand, if the monitoring device 50 determines that the period is not outside the predetermined period, that is, that the period is within the predetermined period, the monitoring device 50, for example, restricts monitoring (step S21). The monitoring device 50 excludes the predetermined period from detecting an abnormality. The monitoring device 50 does not detect an abnormality based on voltage information for the predetermined period. The monitoring restriction can be applied to any of the above-mentioned sudden voltage fluctuations, delays in voltage fluctuations, and delays in threshold switching.

[0100] In step S21, the monitoring device 50 may execute a process of applying a threshold value before the transition instead of limiting the monitoring. For example, the threshold value set during vertical movement is maintained for a predetermined period during the transition from vertical movement to horizontal movement. The application of the threshold value before the transition can be applied to the delay in voltage fluctuation and the delay in threshold switching described above. The monitoring device 50 may execute a process of applying an upper limit voltage or a lower limit voltage allowed for the battery 14 as a threshold instead of limiting the monitoring. The application of the allowable upper limit voltage or lower limit voltage can be applied to the delay in voltage fluctuation and the delay in threshold switching described above. In this way, the threshold value may be limited to a predetermined value.

[0101] After executing the process of step S21, the monitoring device 50 executes the processes from step S30 onwards, similar to the method shown in FIG.

[0102] The monitoring method may be the method shown in FIG. 20 . First, the monitoring device 50 executes steps S10 and S20, similar to the method shown in FIG. 16 . Next, the monitoring device 50 determines whether the difference between the assembled battery voltage Vb and the sum of all cell voltages Vc is equal to or less than a predetermined value (step S25). The monitoring device 50 diagnoses whether abnormality detection is being performed normally. The sum of all cell voltages Vc is the sum of the voltages (cell voltages Vc) of all battery cells 142 in the assembled battery 141 that generate the assembled battery voltage Vb. The predetermined value may be set based on the difference between the normal assembled battery voltage Vb during flight and the sum of all cell voltages Vc, derived, for example, through prior experiments or battery simulations. The predetermined value may also be set with a predetermined margin of error relative to the derived difference.

[0103] If it is determined in step S25 that the difference is within the predetermined value, the monitoring device 50 executes the processing from step S30 onward, similar to the method shown in Fig. 16. On the other hand, if it is determined that the difference is not equal to or less than the predetermined value, that is, the difference is greater than the predetermined value, the monitoring device 50 outputs a message indicating that a monitoring abnormality is suspected (step S41) and ends the series of processing. If the difference is not equal to or less than the predetermined value, the monitoring device 50 does not execute the processing of steps S30 and S40, that is, does not detect an abnormality, and ends the series of processing.

[0104] In the method shown in Fig. 16, if the battery information is within the allowable threshold range, the monitoring device 50 may output a message indicating that no abnormality is present, and then terminate the series of processes. The same applies to the methods shown in Fig. 17 and Fig. 20.

[0105] The determination unit 52 (detection unit) of the monitoring device 50 may execute the process of step S15 and the process of step S21 shown in Fig. 17. A functional unit other than the determination unit 52 may execute at least one of the process of step S15 and the process of step S21.

[0106] Summary of First Embodiment As described above, when the eVTOL 10 (electric flying vehicle) moves vertically, the battery 14 is required to discharge a large current for a predetermined period of time. Monitoring the battery voltage, which is sensitive to internal short circuits and rapid deterioration that can cause thermal runaway in the battery 14, is used as a means of early detection of abnormalities. However, during flight, the discharge load of the battery 14 fluctuates greatly, and the battery voltage also fluctuates drastically. For this reason, it is difficult to detect abnormalities early using management that uses a fixed value (constant value) as a threshold.

[0107] The monitoring device 50 of this embodiment acquires information about the travel mode along with voltage information about the battery 14, and monitors the voltage information using a threshold value set for each travel mode. This allows for early detection of abnormalities in the battery 14, thereby improving flight safety.

[0108] The monitoring device 50 is preferably applied to a configuration in which the maximum discharge rate of the battery 14 during vertical movement of the eVTOL 10 is 1.5 times or more the maximum discharge rate during horizontal movement. The monitoring device 50 is preferably applied to a configuration in which the discharge rate during vertical movement is 3C or more.

[0109] As described above, electric flying vehicles such as the eVTOL 10 have large fluctuations in discharge characteristics. The greater the fluctuations in discharge characteristics, the greater the effectiveness of early detection by the monitoring device 50. For example, when the ratio of the maximum discharge rate during vertical movement to the maximum discharge rate during horizontal movement is 1.5 times or more, the effectiveness of early detection is enhanced. When the ratio is even higher, for example, 2 times or more, 3 times or more, or 5 times or more, even greater effectiveness can be achieved. The higher the discharge rate during vertical movement, the greater the effectiveness of early detection by the monitoring device 50. When the discharge rate is 3C or more, the effectiveness of early detection is enhanced. When the discharge rate is even higher, for example, 5C or more, 7C or more, or 10C or more, even greater effectiveness can be achieved.

[0110] The monitoring device 50 may acquire information about the battery discharge characteristics and / or flight information as information about the travel mode. By using this information, the threshold value can be switched at an appropriate timing depending on the travel mode.

[0111] The monitoring device 50 sets a threshold value for each travel mode based on discharge characteristic information and battery state information, which are information related to the travel mode. As shown in Equation 1, a predetermined relationship holds between the battery voltage, OCV, discharge current, and battery resistance during discharge. By reflecting the discharge characteristic information (discharge current) and battery state information (OCV, battery resistance), which affect the battery voltage, in the setting of the threshold value, it becomes possible to detect abnormalities earlier and with higher accuracy.

[0112] The monitoring device 50 may use information on the resistance increase caused by the concentration imbalance of ions that contribute to the battery reaction to set the threshold value, thereby suppressing false detection due to the resistance increase caused by temporary deterioration and improving the reliability of abnormality detection.

[0113] The monitoring device 50 may use battery status information that is updated before flight based on a battery status diagnosis performed when the aircraft is parked. The battery status information is updated for each flight. Using battery status information that is updated for each flight can further improve the accuracy of detecting abnormalities.

[0114] The monitoring device 50 may change the threshold value based on changes in the battery state during flight. By changing the threshold value based on fluctuations in the battery voltage, it becomes possible to detect abnormalities earlier and with higher accuracy.

[0115] The monitoring device 50 preferably acquires at least one of the following voltage information: the absolute value of the battery pack voltage Vb, the absolute value of the cell voltage Vc, the rate of change of the battery pack voltage Vb, the rate of change of the cell voltage Vc, and the variation of the cell voltage Vc. By using the above parameters, which respond sensitively to internal short circuits and sudden degradation, it is possible to detect abnormalities with high accuracy. In particular, by monitoring using multiple parameters, it is possible to further increase the accuracy of abnormality detection.

[0116] The monitoring device 50 may acquire, as voltage information, information on the battery pack voltage Vb and information on the cell voltage Vc from different sources. For example, the monitoring device 50 may acquire the battery pack voltage information from the EPU 15 and the cell voltage information from the BMS 16. Monitoring using data from different independent measurements, that is, multiplexing of diagnoses, can improve reliability.

[0117] The monitoring device 50 may diagnose whether abnormality detection is being performed normally by using the battery pack voltage Vb and the total voltage obtained by adding up all the cell voltages Vc in the battery pack 141. This makes it possible to prevent erroneous determination of abnormality detection.

[0118] During a predetermined period of transition between vertical and horizontal movement, the monitoring device 50 may limit abnormality detection, apply the threshold value before the transition, or apply the upper or lower limit voltage allowed for the battery 14 as the threshold. This can reduce erroneous determinations due to normal sudden fluctuations in battery voltage information, delays in battery voltage fluctuations due to normal transient responses, and delays in threshold switching, thereby improving the reliability of abnormality detection.

[0119] The monitoring method of this embodiment is executed by a processor to monitor the battery 14. The monitoring method includes acquiring voltage information and travel mode information of the battery 14 during flight, and outputting a monitoring result if a predetermined condition related to an abnormality in the battery 14 is met using the voltage information and a threshold set for each travel mode. In this way, by using the threshold set for each travel mode, an abnormality in the battery 14 can be detected early, thereby improving flight safety.

[0120] The program of this embodiment is stored in a storage medium and includes instructions to be executed by a processor for monitoring the battery 14. The program includes instructions to acquire voltage information and travel mode information of the battery 14 during flight, and to output monitoring results when predetermined conditions related to an abnormality in the battery 14 are met using the voltage information and thresholds set for each travel mode. In this way, by using thresholds set for each travel mode, abnormalities in the battery 14 can be detected early, thereby improving flight safety.

[0121] (Other Embodiments) The disclosure in this specification and drawings, etc. is not limited to the exemplified embodiments. The disclosure encompasses the exemplified embodiments and modifications thereto by those skilled in the art. For example, the disclosure is not limited to the combinations of parts and / or elements shown in the embodiments. The disclosure can be implemented in various combinations. The disclosure can have additional parts that can be added to the embodiments. The disclosure encompasses the omission of parts and / or elements from the embodiments. The disclosure encompasses the substitution or combination of parts and / or elements between one embodiment and another embodiment. The disclosed technical scope is not limited to the description of the embodiments. Some disclosed technical scopes are defined by the claims, and should be interpreted as including all modifications within the meaning and scope equivalent to the claims.

[0122] The disclosure in the specification, drawings, etc. is not limited by the claims. The disclosure in the specification, drawings, etc. encompasses the technical ideas described in the claims, and extends to more diverse and broader technical ideas than the technical ideas described in the claims. Therefore, various technical ideas can be extracted from the disclosure in the specification, drawings, etc. without being bound by the claims.

[0123] When an element or layer is referred to as being "on," "coupled," "connected," or "coupled," it may be directly on, coupled, connected, or coupled to another element or layer, and intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on," "directly coupled," "directly connected," or "directly coupled" to another element or layer, there are no intervening elements or layers present. Other language used to describe relationships between elements should be construed in a similar manner (e.g., "between" vs. "directly between," "adjacent" vs. "directly adjacent," etc.). As used in this specification, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0124] The various flowcharts shown in this disclosure are merely examples, and the number of steps constituting the flowcharts and the order of execution of the processes can be changed as appropriate. Furthermore, the devices, systems, and methods described herein may be implemented by a special-purpose computer comprising a processor programmed to perform one or more functions embodied in a computer program. The devices and methods described herein may be implemented using special-purpose hardware logic circuits. Furthermore, the devices and methods described herein may be implemented by one or more special-purpose computers configured by combining a processor executing a computer program with one or more hardware logic circuits.

[0125] For example, some or all of the functions of the processor 311 may be realized as hardware. A form in which a certain function is realized as hardware includes a form in which it is realized using one or more ICs, etc. As the processor (computation core), a CPU, MPU, GPU, DFP, etc. can be used. CPU is an abbreviation for Central Processing Unit. MPU is an abbreviation for Micro-Processing Unit. GPU is an abbreviation for Graphics Processing Unit. DFP is an abbreviation for Data Flow Processor.

[0126] Some or all of the functions of the processor 201 may be realized by combining multiple types of arithmetic processing devices. Some or all of the functions of the processor 201 may be realized using SoC, ASIC, FPGA, etc. SoC is an abbreviation for System on Chip. ASIC is an abbreviation for Application Specific Integrated Circuit. FPGA is an abbreviation for Field-Programmable Gate Array. The same applies to the processor 311.

[0127] Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory tangible storage medium. Examples of storage media for the program include HDDs, SSDs, and flash memories. HDD stands for Hard-Disk Drive. SSD stands for Solid State Drive. The scope of this disclosure also includes programs for causing a computer to function as a control device or control system, and non-transitory tangible storage media such as semiconductor memories on which the programs are recorded.

[0128] (Disclosure of Technical Ideas) This specification discloses multiple technical ideas described in the following multiple clauses. Some clauses may be described in a multiple dependent form, with the subsequent clause alternatively referring to the preceding clause. Furthermore, some clauses may be described in a multiple dependent form, with the subsequent clause referring to another multiple dependent clause. These multiple dependent clauses define multiple technical ideas.

[0129] <Technical Idea 1> A monitoring device that monitors a battery (14) mounted on an electric flying object (10), comprising: an acquisition unit (51) that acquires voltage information of the battery during flight and information related to the travel mode of the electric flying object; and an output unit (53) that outputs a monitoring result when a predetermined condition related to an abnormality in the battery is met using the voltage information and a threshold value set for each of the travel modes.

[0130] <Technical Concept 2> The monitoring device according to Technical Concept 1, wherein the maximum discharge rate of the battery when the electric flying object is moving in a vertical direction is 1.5 times or more the maximum discharge rate when the electric flying object is moving in a horizontal direction.

[0131] <Technical Concept 3> The monitoring device according to Technical Concept 2, wherein the discharge rate during the vertical movement is 3C or more.

[0132] <Technical Concept 4> The monitoring device according to any one of Technical Concepts 1 to 3, wherein the acquisition unit acquires discharge characteristic information of the battery and / or flight information as the information related to the travel mode.

[0133] <Technical Idea 5> The monitoring device according to Technical Idea 4, wherein the acquisition unit acquires the discharge characteristic information and battery state information as information relating to the travel mode, and the monitoring device includes a setting unit (54) that sets the threshold for each of the travel modes based on the discharge characteristic information and the battery state information.

[0134] <Technical Concept 6> The monitoring device according to Technical Concept 5, wherein the battery state information includes information on an increase in resistance caused by a concentration imbalance of ions that contribute to a battery reaction.

[0135] <Technical Idea 7> The monitoring device according to Technical Idea 5 or 6, wherein the setting unit uses the battery status information that is updated before flight by a battery status diagnosis performed when the aircraft is parked.

[0136] <Technical Concept 8> The monitoring device according to any one of Technical Concepts 5 to 7, wherein the setting unit successively changes the set threshold value based on a change in battery state during flight.

[0137] <Technical Idea 9> The monitoring device according to any one of Technical Ideas 1 to 8, wherein the battery includes an assembled battery (141) configured with a plurality of battery cells (142), and the acquisition unit acquires at least one of an absolute value of assembled battery voltage, an absolute value of cell voltage, a rate of change of the assembled battery voltage, a rate of change of the cell voltage, and a variation in the cell voltage, as the voltage information.

[0138] Technical Idea 10 The monitoring device according to Technical Idea 9, wherein the acquisition unit acquires, as the voltage information, information relating to the battery pack voltage and information relating to the cell voltage from different acquisition targets.

[0139] <Technical Idea 11> The monitoring device according to Technical Idea 10, further comprising a diagnosing unit (52) that diagnoses whether abnormality detection is being performed normally, using the assembled battery voltage and a total voltage obtained by adding up all of the cell voltages in the assembled battery.

[0140] Technical Idea 12: The monitoring device according to any one of Technical Ideas 1 to 11, including a limiting unit (52) that, during a predetermined period of transition between vertical movement and horizontal movement, limits detection of abnormalities, applies the threshold value before the transition, and applies an upper limit voltage or a lower limit voltage allowable for the battery as the threshold value.

Claims

1. A monitoring device that monitors a battery (14) mounted on an electric flying object (10), comprising: an acquisition unit (51) that acquires voltage information of the battery during flight and information related to the travel mode of the electric flying object; and an output unit (53) that outputs a monitoring result when a predetermined condition related to an abnormality of the battery is satisfied using the voltage information and a threshold value set for each of the travel modes.

2. The monitoring device according to claim 1, wherein the maximum discharge rate of the battery during vertical movement of the electric flying object is 1.5 times or more the maximum discharge rate during horizontal movement.

3. The monitoring device according to claim 2, wherein the discharge rate during the vertical movement is 3C or more.

4. The monitoring device according to claim 1, wherein the acquisition unit acquires discharge characteristic information of the battery and / or flight information as information relating to the travel mode.

5. The monitoring device of claim 4, wherein the acquisition unit acquires the discharge characteristic information and battery status information as information relating to the travel mode, and includes a setting unit (54) that sets the threshold for each travel mode based on the discharge characteristic information and the battery status information.

6. The monitoring device according to claim 5, wherein the battery state information includes information on an increase in resistance caused by a concentration bias of ions that contribute to the battery reaction.

7. The monitoring device according to claim 5, wherein the setting unit uses the battery status information updated before flight by a battery status diagnosis performed when the aircraft is parked.

8. A monitoring device as described in any one of claims 5 to 7, wherein the setting unit successively changes the set threshold value based on changes in battery status during flight.

9. The monitoring device of claim 1, wherein the battery includes an assembled battery (141) having a plurality of battery cells (142), and the acquisition unit acquires at least one of the absolute value of the assembled battery voltage, the absolute value of the cell voltage, the rate of change of the assembled battery voltage, the rate of change of the cell voltage, and the variation of the cell voltage as the voltage information.

10. The monitoring device according to claim 9, wherein the acquisition unit acquires, as the voltage information, information relating to the battery pack voltage and information relating to the cell voltage from different acquisition targets.

11. The monitoring device according to claim 10, further comprising a diagnostic unit (52) that diagnoses whether abnormality detection is being performed normally using the assembled battery voltage and a total voltage obtained by adding up all of the cell voltages in the assembled battery.

12. The monitoring device of claim 1, further comprising a limiting unit (52) that performs one of the following during a predetermined period of transition between vertical and horizontal movement: limiting detection of anomalies, applying the threshold value before the transition, and applying an upper or lower limit voltage allowable for the battery as the threshold value.

13. A monitoring method executed by a processor (201) to monitor a battery (14) mounted on an electric flying object (10), comprising: acquiring voltage information of the battery during flight and information related to the travel mode of the electric flying object; and outputting a monitoring result when a predetermined condition related to an abnormality in the battery is met using the voltage information and a threshold value set for each travel mode.

14. A program stored in a storage medium (203) for monitoring a battery (14) mounted on an electric flying object (10), the program including instructions to be executed by a processor (201), the program including the instructions to execute the following: acquiring voltage information of the battery during flight and information regarding the movement mode of the electric flying object; and outputting a monitoring result when a predetermined condition regarding an abnormality of the battery is met using the voltage information and a threshold value set for each movement mode.

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