Backup power systems and vehicles

Abstract

The present invention is a backup power supply system, which includes a detection unit, a power storage unit and a control unit. The detection unit detects an abnormality of a power supply that provides power to multiple loads. The power storage unit provides power to multiple loads when the detection unit detects the abnormality of the power supply. The control unit monitors the remaining power of the power storage unit. If the remaining power of the power storage unit is lower than a threshold power, the load to which the power storage unit provides power is limited.

Description

Technical Field

[0001] The present disclosure relates to a backup power supply system and a vehicle, and more particularly, to a backup power supply system including a power storage unit for backing up power supply for supplying electric power to a plurality of loads, and a vehicle equipped with the backup power supply system. Background Art

[0002] The backup device for a vehicle described in Patent Document 1 provides backup for multiple drive sources by supplying power from a second power supply unit (power storage unit) when the power supply from a first power supply unit (power supply) is interrupted. In the backup device, when the control unit detects an abnormal state of the power supply from the first power supply unit, the control unit instructs the discharge unit to make the discharge current from the second power supply unit flow to each of the multiple drive sources intermittently for multiple times. In addition, the control unit controls the supply object of the discharge current so that the respective instruction times for instructing the discharge unit to make the discharge current from the second power supply unit flow to each of the multiple drive sources are staggered with the respective instruction times for instructing the discharge unit to make the discharge current from the second power supply unit flow to other drive sources. That is, the power from the second power supply unit is provided to the multiple drive sources in a time-divided process. As a result, the discharge current is concentrated on the multiple drive sources at the same time.

[0003] Prior Art Literature

[0004] Patent Literature

[0005] Patent Document 1: International Publication No. 2018 / 061750 Summary of the invention

[0006] In the backup device (backup power supply system) described in patent document 1, power from the second power supply unit is provided to multiple drive sources (loads) in a time-divided manner, but in this providing method, when the remaining power of the second power supply unit decreases, power may sometimes not be provided to important drive sources (loads).

[0007] The present disclosure has been made in view of the above-mentioned problems, and an object thereof is to provide a backup power supply system capable of preferentially supplying power to important loads even when the remaining power of the power storage unit decreases, and a vehicle equipped with the backup power supply system.

[0008] A backup power supply system according to one embodiment of the present disclosure includes a detection unit, a power storage unit, and a control unit. The detection unit detects an abnormality of a power supply that supplies power to a plurality of loads. The power storage unit supplies power to the plurality of loads when the detection unit detects an abnormality of the power supply. The control unit monitors the remaining power of the power storage unit, and if the remaining power of the power storage unit is lower than a threshold power, limits the loads to which the power storage unit supplies power.

[0009] A vehicle according to one aspect of the present disclosure includes: the backup power supply system according to the above-mentioned aspect; and a vehicle body on which the backup power supply system is mounted.

[0010] The present disclosure has an effect of being able to preferentially supply electric power to important loads even when the remaining amount of the electric storage unit is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a side view showing a partial cross section of a vehicle equipped with the backup power supply system according to the embodiment.

[0012] Figure 2 It is a block diagram of a backup power supply system according to an embodiment.

[0013] Figure 3 This is a timing chart explaining the method of obtaining the threshold voltage.

[0014] Figure 4 This is an explanatory diagram for explaining the operation of a main portion (switch control unit) of the control circuit.

[0015] Figure 5 This is an explanatory diagram for explaining the operation of the main portion (switch control unit) of the control circuit of Modification Example 2. DETAILED DESCRIPTION

[0016] (Implementation Method)

[0017] The embodiment and modification examples described below are merely examples of the present disclosure, and the present disclosure is not limited to the embodiment and modification examples. Various changes can be made according to design, etc., other than the embodiment and modification examples, without departing from the scope of the technical concept of the present disclosure.

[0018] (summary)

[0019] Reference Figure 2 The backup power supply system 1 according to the present embodiment will be described. The backup power supply system 1 according to the present embodiment provides power to a plurality of electrical devices 5 (loads) instead of the main power supply 4 when an abnormality occurs in the main power supply 4. Thus, even when the power supply from the main power supply 4 stops, the plurality of electrical devices 5 can continue to operate by the power supply from the backup power supply system 1.

[0020] The backup power supply system 1 is mounted on a vehicle (a moving object that travels by wheels, such as a four-wheeled vehicle) 9 and used ( Figure 1The vehicle 9 includes a drive system 10 and a vehicle body 91 (vehicle body) on which the drive system 10 is mounted. The drive system 10 includes a backup power supply system 1, a main power supply 4, and a plurality of electrical devices 5. The main power supply 4 is a storage battery (e.g., a lead-acid battery) mounted on the vehicle and is configured to supply power to the plurality of electrical devices 5.

[0021] In the present embodiment, the plurality of electric devices 5 are two, namely, the shift-by-wire system 50 and the brake system 60. Although in the present embodiment, the plurality of electric devices 5 are two, namely, the shift-by-wire system 50 and the brake system 60, the number of electric devices 5 may be three or more.

[0022] The shift-by-wire system 50 is a system for switching the shift position of an automatic transmission mounted on a vehicle by electric power. The shift-by-wire system 50 includes a drive control unit 51 and an actuator 52. The drive control unit 51 outputs a control signal to the actuator 52 based on the position of the shift lever operated by the driver, thereby controlling the drive of the actuator 52. The actuator 52 is configured to switch the shift position of the automatic transmission 6 according to the control signal from the drive control unit 51.

[0023] The shift positions of the automatic transmission include a parking position (P position), a reverse position (R position), a neutral position (N position), and a drive position (D position). The drive position is used when the vehicle is moving forward, the reverse position is used when the vehicle is moving backward, and the parking position is used when the vehicle is parked. In the parking position, the rotating shaft in the automatic transmission is locked by the actuator 52, and the movement of the vehicle is locked.

[0024] The brake system 60 is a system that electrically actuates the brake mechanism provided at each wheel of the vehicle. The brake system 60 includes a drive control unit 61 and an actuator 62. The drive control unit 61 outputs a control signal to the actuator 62 based on the amount of operation of the brake pedal by the driver, thereby controlling the drive of the actuator 62. The actuator 62 is configured to actuate the brake mechanism provided at each wheel according to the control signal from the drive control unit 61, thereby applying brakes to each wheel.

[0025] The shift-by-wire system 50 and the brake system 60 are configured to be operated by electric power supplied from the main power supply 4 or the backup power supply system 1 .

[0026] When the main power supply 4 is normal, power is supplied from the main power supply 4 to the plurality of electrical devices 5 (i.e., each system 50, 60). On the other hand, when an abnormality occurs in the main power supply 4, power is supplied from the backup power supply system 1 to the plurality of electrical devices 5. Therefore, even when an abnormality occurs in the main power supply 4, the plurality of electrical devices 5 can be operated according to the operation of the driver. In addition, the so-called abnormality of the main power supply 4 means, for example, that the output voltage of the main power supply 4 is reduced to a predetermined voltage value or less (in other words, a power failure) due to a failure or degradation of the main power supply 4.

[0027] In this embodiment, if the remaining power of the backup power supply system 1 decreases, the electrical equipment 5 to which the power is supplied is limited. That is, power is supplied only to specific electrical equipment 5 (specific load) among the multiple electrical equipment 5, and the power supply to other electrical equipment 5 (non-specific load) is stopped. In this way, power can be supplied to important electrical equipment (i.e., specific electrical equipment) 5 first, ensuring the operation of the important electrical equipment 5.

[0028] (structure)

[0029] like Figure 2 As shown, the backup power supply system 1 of the present embodiment comprises: a power storage unit 20, a charging and discharging circuit 21 (voltage transformation circuit), a power supply circuit 22, a control circuit 3, multiple switches SW1, SW2, diodes D5~D9, a communication unit 23, multiple (for example 2) input terminals T1~T2, multiple (for example 2) output terminals T4, T5, and circuits DR7~DR13.

[0030] Here, the main power supply 4 is connected to the main circuit DR1, and the main circuit DR1 is connected to a plurality of branch circuits DR2 to DR4. The power from the main power supply 4 is supplied to the backup power supply system 1 and a plurality of electrical devices 5 via the main circuit DR1 and the plurality of branch circuits DR2 to DR4.

[0031] The input terminal T1 is connected to the main circuit DR1 (therefore, the main power supply 4) via the branch line DR2, and inputs the power from the main power supply 4. The input terminal T2 is connected to the main circuit DR1 via the ignition switch SW3, and inputs the on signal or the off signal from the ignition switch SW3. The output terminal T3 is connected to the branch line DR3 via the circuit DR5, and outputs power to the shift-by-wire system 50. The output terminal T4 is connected to the branch line DR4 via the circuit DR6, and outputs power to the brake system 60.

[0032] The branch DR3 and the circuit DR5 are connected to the diodes D1 and D2, respectively. The cathodes of the diodes D1 and D2 are connected to each other and to the shift-by-wire system 50. Through the diodes D1 and D2, the power from the output terminal T3 and the branch DR3, whichever has a higher voltage, is output to the shift-by-wire system 50. That is, when the voltage of the output terminal T3 is high, the diode D2 is turned on and the diode D1 is turned off, so that the power from the output terminal T3 is output to the shift-by-wire system 50 via the diode D2. In addition, when the voltage of the branch DR3 is high, the diode D1 is turned on and the diode D2 is turned off, so that the power from the branch DR3 is output to the shift-by-wire system 50 via the diode D1.

[0033] In addition, when the main power supply 4 is not abnormal, as described below, the switch SW1 is turned off. Therefore, the voltage of the branch DR3 is higher than the output terminal T3, so the diode D1 is turned on and the diode D2 becomes non-conductive. As a result, the power from the branch DR3 (i.e., the main power supply 4) is output to the shift-by-wire system 50. In this case, the switch SW1 is turned off, so that the output terminal T3 (i.e., the storage unit 20) and the shift-by-wire system 50 are electrically disconnected. On the other hand, when the main power supply 4 is abnormal, as described below, the switch SW1 is turned on. Therefore, the voltage of the output terminal T3 becomes higher than the branch DR3, so the diode D1 becomes non-conductive and the diode D2 is turned on. As a result, the power from the output terminal T3 (i.e., the storage unit 20) is output to the shift-by-wire system 50. In this case, the diode D1 becomes non-conductive, so that the main power supply 4 and the shift-by-wire system 50 are electrically disconnected.

[0034] Similarly, the circuit DR6 and the branch DR4 are connected to the diodes D3 and D4, respectively. The cathodes of the diodes D3 and D4 are connected to each other and to the brake system 60. The power from the output terminal T4 and the branch DR4, whichever has a higher voltage, is output to the brake system 60 through the diodes D3 and D4.

[0035] In addition, when the main power supply 4 is not abnormal, as described below, the switch SW2 is turned off. Therefore, the voltage of the branch DR4 is higher than the output terminal T4, so the diode D4 is turned on and the diode D3 becomes non-conductive. As a result, the power from the branch DR4 (i.e., the main power supply 4) is output to the brake system 60. In this case, the switch SW2 is turned off, so that the output terminal T4 (i.e., the storage unit 20) and the brake system 60 are electrically disconnected. On the other hand, when the main power supply 4 is abnormal, as described below, the switch SW2 is set to be turned on. Therefore, the voltage of the output terminal T4 becomes higher than the branch DR4, so the diode D3 becomes conductive and the diode D4 becomes non-conductive. As a result, the power from the output terminal T4 (i.e., the storage unit 20) is output to the brake system 60. In this case, the diode D4 becomes non-conductive, so that the main power supply 4 and the brake system 51 are electrically disconnected.

[0036] Circuits DR7 to DR9 are connected between the input terminal T1 and the two output terminals T3 and T4. One end of circuit DR7 is connected to the input terminal T1, and the other end (connection point N1) of circuit DR7 is connected to one end of a plurality of (e.g., two) circuits DR8 and DR9. One end of the plurality of circuits DR8 and DR9 is connected to the other end of circuit DR7, and the other ends of the plurality of circuits DR8 and DR9 are connected to the plurality of output terminals T3 and T4, respectively.

[0037] In the circuit DR7, a diode D5, a charge and discharge circuit 21, and a diode D6 are provided in order from the input terminal T1 side to the connection point N1 side. The cathodes of the diodes D6 and D7 are connected to the connection point N1 side, and the anode of the diode D5 is connected to the input terminal T1 side.

[0038] In the circuit DR7, the power storage unit 20 is connected to the connection point N2 between the charge and discharge circuit 21 and the diode D6 via the circuit DR10. The input and output terminals of the power storage unit 20 are connected to the control circuit 3 via the circuit DR11, and the output voltage of the power storage unit 20 is input to the control circuit 3 via the circuit DR11. The cathode of the diode D5 is connected to the charge and discharge circuit 21, and the anode of the diode D5 is connected to the input terminal T1. Between the two connection points N1 and N3, the circuit DR12 is connected. The connection point N3 is the connection point between the diode D5 and the charge and discharge circuit 21. In the circuit DR12, a diode D7 is provided. The cathode of the diode D7 is connected to the connection point N1, and the anode of the diode D7 is connected to the connection point N3.

[0039] The connection point N3 of the circuit DR7 is connected to the control circuit 3 via the circuit DR13. In the circuit DR13, a diode D8 and a power supply circuit 22 are sequentially provided from the connection point N3 to the control circuit 3. The cathode of the diode D8 is connected to the power supply circuit 22, and the anode of the diode D8 is connected to the connection point N3. The input end of the power supply circuit 22 is connected to the control circuit 3 via the circuit DR13, and the input voltage of the power supply circuit 22 (that is, the output voltage of the main power supply 4) is input to the control circuit 3. A diode D9 is connected between the input terminal T2 and the power supply circuit 22. The cathode of the diode D9 is connected to the power supply circuit 22, and the anode of the diode D9 is connected to the input terminal T2. Thus, the on signal or the off signal of the ignition switch SW3 is input to the power supply circuit 22 via the diode D9. Switches SW1 and SW2 are provided in the two circuits DR8 and DR9, respectively.

[0040] The power storage unit 20 is a backup (i.e., auxiliary or reserve) power source for the main power source 4. The power storage unit 20 is, for example, an electrical double layer capacitor (EDLC). In addition, the power storage unit 20 may also be, for example, a secondary battery such as a lithium ion capacitor (LIC) or a lithium ion battery (LIB). In addition, a lithium ion capacitor is a capacitor in which the positive electrode is formed by the same material as that of an EDLC (e.g., activated carbon), and the negative electrode is formed by the same material as that of a LIB (e.g., a carbon material such as graphite).

[0041] In addition, each power storage unit 20 is not limited to a double-layer capacitor, and for example, may also be an electrochemical device having a structure described below. The electrochemical device referred to here comprises a positive electrode component, a negative electrode component, and a non-aqueous electrolyte. The positive electrode component comprises: a positive electrode collector, a positive electrode material layer supported on the positive electrode collector and containing a positive electrode active material. The positive electrode material layer comprises a conductive polymer as a positive electrode active material that dopes and dedopes anions (dopants). The negative electrode component comprises a negative electrode material layer containing a negative electrode active material. As an example, the negative electrode active material is a substance that undergoes an oxidation-reduction reaction accompanied by the absorption and release of lithium ions, specifically, a carbon material, a metal compound, an alloy or a ceramic material. As an example, a non-aqueous electrolyte has lithium ion conductivity. This non-aqueous electrolyte contains a lithium salt and a non-aqueous solution that dissolves the lithium salt. An electrochemical device with such a structure has a higher energy density than a double-layer capacitor, etc.

[0042] In addition, the power storage unit 20 may be formed by two or more power storage devices (such as electric double layer capacitors) electrically connected in parallel, in series, or in parallel and in series. That is, one power storage unit 20 may be realized by a parallel circuit or a series circuit of two or more power storage devices, or a combination thereof.

[0043] The charge-discharge circuit 21 is a circuit that charges and discharges the power storage unit 20 under the control of the control circuit 3. The charge-discharge circuit 21 is, for example, a bidirectional buck-boost circuit. When the charge-discharge circuit 21 functions as a charge circuit, a voltage is input from the connection point N3 side, the input voltage is stepped down, and the output is to the connection point N2 side. When the charge-discharge circuit 21 functions as a discharge circuit, a voltage is input from the connection point N2 side, the input voltage is stepped up, and the output is to the connection point N3 side.

[0044] In more detail, the charge-discharge circuit 21 functions as a charging circuit when charging the power storage unit 20. In this case, the charge-discharge circuit 21 inputs the output voltage of the main power supply 4 input to the input terminal T1 via the diode D5, steps down the input voltage, and outputs it to the power storage unit 20. Thus, the power storage unit 20 is charged by the output power of the main power supply 4.

[0045] In addition, the charge-discharge circuit 21 functions as a discharge circuit when discharging the power storage unit 20 (i.e., when the main power supply 4 is abnormal). In this case, the charge-discharge circuit 21 boosts the output voltage of the power storage unit 20 and outputs it to the connection point N3 (i.e., discharge). As a result, the output power of the power storage unit 20 is output to the connection point N1 via the charge-discharge circuit 21 and the diode D7. In addition, during the period from when the output voltage of the power storage unit 20 is boosted by the charge-discharge circuit 21 (i.e., during the period when the discharge voltage of the charge-discharge circuit 21 is lower than the output voltage of the power storage unit 20), the diode D6 is turned on and the diode D7 is non-conductive. Therefore, during this period, the output voltage of the power storage unit 20 is output to the connection point N1 via the diode D6. And, if the output voltage of the power storage unit 20 is boosted by the charge-discharge circuit 21, the diode D7 is turned on and the diode D6 is non-conductive. As a result, the output voltage of the power storage unit 20 is output to the connection point N1 via the charge-discharge circuit 21 and the diode D7. The voltage output to the connection point N1 is output from the output terminal T3 via the switch SW1, and is output from the output terminal T4 via the switch SW2. Thus, the output power of the power storage unit 20 is supplied from the output terminal T3 to the drive control unit 51 and the actuator 52 of the shift-by-wire system 50, and is supplied from the output terminal T4 to the drive control unit 61 and the actuator 62 of the brake system 60.

[0046] In addition, in the backup power supply system 1 of the present embodiment, power is supplied to the drive control unit 51 and the actuator 52 of the shift-by-wire system 50 through the same circuit, but it can also be configured to supply power through different circuits. In this case, the voltage values ​​of the voltages applied to the drive control unit 51 and the actuator 52 can be different from each other. Similarly, power is supplied to the drive control unit 61 and the actuator 62 of the brake system 60 through the same circuit, but it can also be configured to supply power through different circuits. In this case, the voltage values ​​of the voltages applied to the drive control unit 61 and the actuator 62 can be different from each other.

[0047] The power supply circuit 22 is a circuit that generates an operating voltage for the control circuit 3. The power supply circuit 22 steps down the output voltage of the main power supply 4 inputted via the input terminal T1 and the diodes D5 and D8 to a predetermined voltage (e.g., 5V), and outputs it to the control circuit 3. Thus, the output power of the main power supply 4 is provided to the control circuit 3, and the control circuit 3 can operate. The power supply circuit 22 operates or stops according to the on signal or off signal of the ignition switch SW3 inputted via the input terminal T2 and the diode D9. That is, the power supply circuit 22 operates according to the on signal of the ignition switch SW3, and stops according to the off signal of the ignition switch SW3.

[0048] The communication unit 23 communicates with the plurality of electrical devices 5 (e.g., wired communication). For example, the communication unit 23 receives various instruction signals from the plurality of electrical devices 5, and outputs the received instruction signals to the control circuit 3. The control circuit 3 operates according to the above-mentioned instruction signals from the plurality of electrical devices 5. In addition, the above-mentioned various instruction signals, for example, include signals for instructing the start and stop of charging and discharging of the power storage unit 20. The instruction signal is, for example, a PWM (Pulse Width Modulation) signal. That is, in the backup power supply system 1, the charging and discharging of the power storage unit 20 can be controlled by the instruction signals from the plurality of electrical devices 5.

[0049] Furthermore, when the backup power supply system 1 limits the electric device 5 supplied with power from the power storage unit 20, the communication unit 23 receives a notification of the content of the limitation from the control circuit 3, and transmits the received notification to the plurality of electric devices 5. Thus, each electric device 5 can be notified of the limitation of the electric device 5 supplied with power from the power storage unit 20.

[0050] The reporting unit 24 is a device that receives the content of the restriction from the control circuit 3 when the backup power supply system 1 limits the electric device 5 supplied with power from the power storage unit 20, and reports the content of the restriction to the driver (user) of the vehicle. The reporting unit 24 is, for example, a display unit (e.g., an indicator), for example, arranged on the dashboard of the vehicle. Through the report of the reporting unit 24, it is possible to report to the driver of the vehicle that the electric device 5 supplied with power from the power storage unit 20 is limited.

[0051] The switches SW1 and SW2 are respectively provided in the circuits DR8 and DR9, and can selectively switch the conduction and disconnection of the circuits DR8 and DR9 according to the control of the control circuit 3. Thus, the output and stop of the output voltages of the output terminals T3 and T4 can be selectively switched according to the control of the control circuit 3. The switches SW1 and SW2 are respectively formed by semiconductor switch elements (e.g., MOSFET (Metal Oxide Semiconductor Field Effect Transistor)).

[0052] Control circuit 3 controls charging and discharging of power storage unit 20 and controls a plurality of switches SW1 and SW2 to limit electric devices 5 to which power storage unit 20 supplies electric power.

[0053] The control circuit 3 is a computer system (e.g., a microcontroller) mainly composed of a processor and a memory. The control circuit 3 realizes the functions of the control circuit 3 (the abnormality detection unit 31, the charge and discharge control unit 32, and the switch control unit 33 described later) by executing the program stored in the memory by the processor. The program can be recorded in the memory in advance, or provided through an electrical communication line such as the Internet, or recorded in a recording medium such as a memory card. The control circuit 3 is configured to start when the ignition switch SW3 is turned on and power is supplied from the power supply circuit 22.

[0054] The control circuit 3 includes an abnormality detection unit 31 (detection unit), a charge and discharge control unit 32 , and a switch control unit 33 (control unit).

[0055] The abnormality detection unit 31 detects whether an abnormality occurs in the main power supply 4, for example, based on the output voltage of the main power supply 4 input to the control circuit 3 via the circuit DR13. For example, the abnormality detection unit 31 does not determine that an abnormality occurs (i.e., does not detect an abnormality) when the voltage of the main power supply 4 is above a certain threshold value, and determines that an abnormality occurs when the voltage of the main power supply 4 is lower than the above-mentioned certain threshold value, and detects an abnormality based on the determination of the abnormality.

[0056] When the abnormality detection unit 31 does not detect the abnormality of the main power supply 4, the charge and discharge control unit 32 controls the charge and discharge circuit 21 as described above so that the storage unit 20 is charged. In addition, when the abnormality detection unit 31 detects the abnormality of the main power supply 4, the charge and discharge control unit 32 controls the charge and discharge circuit 21 as described above so that the storage unit 20 is discharged. In this way, when the abnormality of the main power supply 4 is detected, the storage unit 20 is discharged, and the power supply source for the plurality of electrical devices 5 is switched from the main power supply 4 to the backup power supply system 1 (storage unit 20), and the instantaneous disconnection of the power supplied to the plurality of electrical devices 5 can be suppressed.

[0057] In addition, when the charge and discharge control unit 32 controls the charge and discharge circuit 21 so that the storage unit 20 is charged, when the output voltage of the storage unit 20 is less than the first specified value, the charge and discharge control unit 32 controls the charge and discharge circuit 21 so that the storage unit 20 is charged with a constant current, and when the output voltage of the storage unit 20 is greater than the first specified value, the charge and discharge control unit 32 controls the charge and discharge circuit 21 so that the storage unit 20 is charged with a constant voltage. In addition, when the charge and discharge control unit 32 controls the charge and discharge circuit 21 so that the output voltage (discharge voltage) of the storage unit 20 is boosted to a second specified value (for example, 9V) when the charge and discharge control unit 32 controls the charge and discharge circuit 21 so that the output voltage (discharge voltage) of the storage unit 20 is boosted to a second specified value (for example, 9V). At this time, the output voltage of the charge and discharge circuit 21 is controlled to a voltage at which the plurality of electrical devices 5 can operate normally.

[0058] Switch control unit 33 controls the on / off switching of multiple switches SW1 and SW2 based on the output voltage of power storage unit 20 input to control circuit 3 via circuit DR11. More specifically, switch control unit 33 monitors the output voltage of power storage unit 20 by determining whether the output voltage of power storage unit 20 is lower than a threshold voltage.

[0059] When the abnormality detection unit 31 does not detect the abnormality of the main power supply 4, the switch control unit 33 controls all of the multiple switches SW1 and SW2 to be turned off. As a result, the output of the output voltage of all of the multiple output terminals T3 and T4 is stopped. In addition, the switch control unit 33 controls all of the multiple switches SW1 and SW2 to be turned on from the time when the abnormality detection unit 31 detects the abnormality of the main power supply 4 to the time when it is determined that the output voltage of the storage unit 20 is lower than the threshold voltage. As a result, the output power of the storage unit 20 is output from all of the multiple output terminals T3 and T4. As a result, the output power of the storage unit 20 can be provided to the multiple electrical devices 5 (that is, the two systems 50 and 60).

[0060] Furthermore, if the switch control unit 33 determines that the output voltage of the power storage unit 20 is lower than the threshold voltage, only a specific switch (e.g., SW1) among the multiple switches SW1 and SW2 is controlled to be turned on, and the other switches (e.g., SW2) are controlled to be turned off. As a result, the output power of the power storage unit 20 is output only from the output terminal T3 corresponding to the specific switch SW1 among the multiple output terminals T3 and T4, and the output power of the power storage unit 20 is not output from the output terminal T4 corresponding to the other switch SW2. As a result, the electrical device 5 to which the power storage unit 20 supplies power is limited. More specifically, the output power of the power storage unit 20 is only provided to a specific electrical device 5 (e.g., the shift-by-wire system 50) among the multiple electrical devices 5 (i.e., the two systems 50 and 60).

[0061] That is, in the backup power supply system 1, if the output voltage of the power storage unit 20 is lower than the threshold voltage (in other words, if the remaining power of the power storage unit 20 is lower than the threshold power (i.e., the threshold power corresponding to the threshold voltage)), the power supply to the specific electrical device 5 is ensured by limiting the electrical device 5 to which the power storage unit 20 supplies power to the specific electrical device 5. Thus, the operation of the specific electrical device 5 can be ensured.

[0062] The specific electric device 5 is the most important electric device (ie, the electric device 5 that definitely needs power supply) among the plurality of electric devices 5. Thus, even if the remaining power of the power storage unit 20 is lower than the threshold power, the operation of the important electric device 5 can be ensured.

[0063] In the present embodiment, the specific electrical device 5 is the shift-by-wire system 50 of the shift-by-wire system 50 and the brake system 60. This is because, assuming that the driver stops the vehicle by applying the brake pedal on a slope and finally puts the shift lever into the parking position to lock (shift lock) the automatic transmission, even if the remaining power of the power storage unit 20 decreases, the final shift lock can be performed.

[0064] In the present embodiment, the threshold voltage is a voltage corresponding to the amount of electricity that can be operated at least once (for example, once) by a specific electrical device 5. If the electrical device 5 to which the power storage unit 20 supplies power is limited to the specific electrical device 5, the power supply from the power storage unit 20 to other electrical devices 5 is stopped. Therefore, in the present embodiment, the threshold voltage is set to a voltage value (an extremely small voltage value) corresponding to the amount of electricity that can be operated at least once (for example, once) by a specific electrical device 5, so that the electrical device 5 to which the power storage unit 20 supplies power is difficult to be limited.

[0065] Next, refer to Figure 3 , the method of determining the threshold voltage is described. In this description, it is assumed that Figure 3 Model example. Figure 3In the model case, the multiple electrical devices 5 are the wire-controlled shift system 50 and the brake system 60. The wire-controlled shift system 50 is a specific electrical device 5 (specific load), and the brake system 60 is a non-specific electrical device 5 (non-specific load). Figure 3 In FIG. 1 , the upper stage is a timing chart of the output voltage V1 of the power storage unit 20 , and the lower stage is a timing chart of the output current I1 of the power storage unit 20 .

[0066] exist Figure 3 In the model case of , it is assumed that the driver operates the brake multiple times (for example, three times) (i.e., the brake system 60 as the non-determined electrical device 5 performs multiple (for example, three) actions) to stop the vehicle, and then the driver operates the shift lever to the parking position (i.e., the shift-by-wire system 50 as the specific electrical device 5 performs one action). That is, it is assumed that the actions of the two systems 50 and 60 do not overlap with each other.

[0067] In this case, each time the brake system 60 is operated once (i.e., each time the brake pedal is operated once), the current I_brake is supplied from the power storage unit 20 to the brake system 60. As a result, each time the brake system 60 is operated once, a rectangular current waveform Ia is generated in the timing diagram of the output current of the power storage unit 20. In addition, when the shift-by-wire system 50 is operated once (i.e., when the shift lever is operated to the parking position), the current I_sbw is supplied from the power storage unit 20 to the shift-by-wire system 50. As a result, when the shift-by-wire system 50 is operated once, a rectangular current waveform Ib is generated in the timing diagram of the output current of the power storage unit 20.

[0068] The rise and fall of each current waveform Ia correspond to the start and end of one operation of the brake pedal, respectively. The rise and fall of the current waveform Ib correspond to the start and end of one operation of the shift lever to the parking position, respectively.

[0069] Furthermore, the output voltage V1 of the storage unit 20 decreases according to the current waveforms Ia and Ib of the output current I1 of the storage unit 20. That is, each time the brake pedal is operated, the output voltage V1 of the storage unit 20 decreases sharply at the beginning of the operation, gradually decreases during the operation, and returns to a certain voltage at the end of the operation. Furthermore, each time the brake pedal is operated repeatedly, the lower point of the voltage reduction during each operation becomes lower. In addition, if the shift lever is operated to the parking position, the output voltage V1 of the storage unit 20 decreases sharply during the operation, gradually decreases during the operation, and returns to a certain voltage at the end of the operation. The amount of voltage reduction when the shift lever is operated to the parking position is greater than the amount of voltage reduction in one operation of the brake pedal.

[0070] In this model case, it is considered that the voltage is restored when each operation of the brake pedal and the shift lever is completed. In this case, in the output voltage V1 of the power storage unit 20, the actual voltage reduction amount dV for each operation of the shift lever is the amount obtained by subtracting the recovery voltage amount dV2 at the end of the operation of the brake pedal before the operation of the shift lever from the voltage reduction amount dV1 of the entire operation of the shift lever (i.e., dV=dV1-dV2).

[0071] Here, the reduced voltage amount dV1 is the sum of the reduced voltage amount dV3 and the reduced voltage amount dV4. The reduced voltage amount dV3 is given by the product of the current I_sbw at the start of the operation of the shift lever and the internal resistance R of the storage unit 20 (I_sbw×R) (i.e., dV3=I_sbw×R). In addition, the reduced voltage amount dV4 is given by the value obtained by dividing the change in the charge of the storage unit 20 during the operation of the shift lever (I_sbw×dt) by the capacity C of the storage unit 20 (I_sbw×dt / C) (i.e., dV4=I_sbw×dt / C). In addition, the symbol dt is the operation time of the operation of the shift lever. The recovery voltage amount dV2 is given by the product of the current I_brake at the start of the operation of the brake pedal and the internal resistance R of the storage unit 20 (I_brake×R) (i.e., dV2=I_brake×R). Therefore, the reduced voltage amount dV is given by the calculation formula of Formula 1.

[0072] dV=(I_sbw-I_brake)×R+I_sbw×dt / C…Equation 1

[0073] The reduced voltage amount dV is a voltage corresponding to the amount of electricity that can be used for one operation of the shift-by-wire system 50 in the model case.

[0074] The threshold voltage Vth in this model case is provided as the lowest lower point among the lower points of the multiple operations of the brake system 60 when the lower point of the voltage drop during the operation of the shift-by-wire system 50 coincides with the minimum guaranteed voltage Vmin of the power storage unit 20 (i.e., Vth=dV+Vmin). Therefore, the threshold voltage Vth is given by the calculation formula of Formula 2.

[0075] Vth=(I_sbw-I_brake)×R+I_sbw×dt / C+Vmin…Equation 2

[0076] In addition, the threshold voltage Vth is obtained by using the voltage difference obtained by subtracting the recovery voltage dV2 of the non-specific electrical device 5 (brake system 60) from the reduced voltage dV1 of the specific electrical device 5 (shift-by-wire system 50). In addition, the threshold voltage Vth is obtained by using the value of the current I_sbw supplied to the specific electrical device 5, the internal resistance R of the storage unit 20, and the capacity C of the storage unit 20.

[0077] In this embodiment, the values ​​of the currents I_sbw and I_brake are initially set. The internal resistance R and the capacity C use the values ​​measured in the backup power supply system 1. Alternatively, the internal resistance R and the capacity C may be initially set similarly to the values ​​of the currents I_sbw and I_brake.

[0078] In the present embodiment, the switch control unit 33 calculates the threshold voltage Vth using the calculation formula of Formula 2. The switch control unit 33 calculates the threshold voltage Vth using the calculation formula of Formula 2, for example, when the backup power supply system 1 is started or when the abnormality detection unit 31 detects an abnormality in the main power supply 4 .

[0079] Next, refer to Figure 4 , the operation of the switch control unit 33 is explained. Figure 4 An example of the time variation of the output voltage V1 of the storage unit 20 is shown. In the following description, it is assumed that the abnormality detection unit 31 detects the abnormality of the main power supply 4, the switch control unit 33 controls all the multiple switches SW1 and SW2 to be turned on, and the output power of the storage unit 20 is supplied to all the multiple electrical devices 5. In this case, the switch control unit 33 monitors the output voltage V1 of the storage unit 20 by periodically determining whether the output voltage V1 of the storage unit 20 is lower than the threshold voltage Vth.

[0080] At time t1-t2, the brake system 60 performs one operation. More specifically, at time t1, the brake system 60 starts to operate, and the output voltage of the power storage unit 20 decreases. At time t2, the brake system 60 ends the operation and the voltage recovers. In this example, at time t2, the output voltage V1 of the power storage unit 20 is lower than the threshold voltage Vth. That is, the remaining power of the power storage unit 20 decreases to the power that can be operated once by the specific electrical device 5 (i.e., the shift-by-wire system 50). Therefore, the switch control unit 33 determines that the output voltage V1 is lower than the threshold voltage Vth, and based on the determination result, only the specific switch SW1 among the multiple switches SW1 and SW2 is controlled to be turned on, and the remaining switches SW2 are controlled to be turned off. As a result, the output power of the power storage unit 20 is only provided to the specific electrical device 5 (the shift-by-wire system 50) among the multiple electrical devices 5, and is not provided to other electrical devices 5 (the brake system 60). That is, only the specific electrical device 5 can be operated, and the other electrical devices 5 are stopped. Therefore, even if the driver operates the other electrical equipment 5 (brake system 60 ), the other electrical equipment 5 does not operate.

[0081] Furthermore, at time t3, the specific electrical device 5 (shift-by-wire system 50) starts to operate, and at time t4, its operation ends. Through this operation, the shift lever is operated to the parking position, and the movement of the vehicle is locked. In this way, if the output voltage V1 of the storage unit 20 is lower than the threshold voltage Vth (that is, if the remaining power of the storage unit 20 is lower than the threshold power), power is preferentially supplied to the specific electrical device 5 (shift-by-wire system 50) which is an important electrical device 5, and the operation of the specific electrical device 5 can be ensured.

[0082] (Variation Example)

[0083] Modifications of the above-mentioned embodiment will be described. The following modifications may also be implemented in combination.

[0084] (Variant 1)

[0085] In the above-mentioned embodiment, it is assumed that the remaining power of the storage unit 20 is monitored by monitoring the output voltage V1 of the storage unit 20, but the remaining power of the storage unit 20 can also be directly monitored. If the remaining power is lower than the threshold power, the electrical device 5 to which the power storage unit 20 supplies power is limited.

[0086] (Variant 2)

[0087] In the above embodiment, the threshold voltage Vth is obtained by considering the voltage recovery when the brake system 60 is finished, but it may be obtained without considering the voltage recovery when the brake system 60 is finished.

[0088] Vth=I_sbw×R+I_sbw×dt / C+Vmin…Equation 3

[0089] The calculation formula of Formula 3 is a calculation formula in which the contribution of the recovery voltage dV2 is omitted in the calculation formula of the above-mentioned Formula 2. That is, the threshold voltage Vth of this modification is obtained by using the reduced voltage dV1 of the specific electrical device 5 (the shift-by-wire system 50) without subtracting the recovery voltage dV2 of the non-specific electrical device 5 (the brake system 60).

[0090] In this modification, it is assumed that the output voltage V1 of the power storage unit 20 changes with time. Figure 5time changes. That is, at time t11-t12, the brake system 60 performs an action. In more detail, at time t11, the brake system 60 starts to act, and the output voltage of the storage unit 20 decreases, and at time t2, the brake system 60 ends the action. In this case, when the action of the brake system ends, the voltage is not restored. In this example, at time t12, the output voltage V1 of the storage unit 20 is lower than the threshold voltage Vth. Therefore, the switch control unit 33 determines that the output voltage V1 is lower than the threshold voltage Vth, and based on the determination result, only a specific switch SW1 among the multiple switches SW1 and SW2 is controlled to be turned on, and the remaining switches SW2 are controlled to be turned off. As a result, the output power of the storage unit 20 is only provided to a specific electrical device 5 (shift-by-wire system 50) among the multiple electrical devices 5, and is not provided to other electrical devices 5 (brake system 60).

[0091] Furthermore, at time t13, the specific electrical device 5 (shift-by-wire system 50) starts to operate, and at time t14, the operation ends. Through this operation, the shift lever is operated to the parking position, thereby locking the movement of the vehicle. In this modified example, if the output voltage V1 of the storage unit 20 is lower than the threshold voltage Vth (that is, if the remaining power of the storage unit 20 is lower than the threshold power), power is preferentially supplied to the specific electrical device 5 (shift-by-wire system 50) as an important electrical device, so that the operation of the specific electrical device 5 can be ensured.

[0092] (Variant 3)

[0093] In the above-mentioned embodiment, the switch control unit 33 has only one calculation formula (the calculation formula of Formula 2) for obtaining the threshold voltage Vth, but when there are three or more electrical devices 5, a plurality of calculation formulas for obtaining the threshold voltage Vth may be maintained. In this case, the switch control unit 33 selects one calculation formula from the plurality of calculation formulas according to the change in the output voltage V1 of the power storage unit 20, and uses the selected calculation formula to set the threshold voltage Vth.

[0094] In more detail, when there are more than three electrical devices 5, there are multiple non-specific electrical devices 5. Depending on the non-specific electrical device 5, the amount of voltage reduction at the start of the action (i.e., the way the voltage is reduced) and the amount of voltage recovery at the end of the action (i.e., the way the voltage is recovered) are different. Therefore, an operation formula for obtaining the threshold voltage Vth is prepared for each non-specific electrical device 5. That is, the switch control unit 33 is provided with multiple operation formulas for obtaining the threshold voltage Vth. And, based on the way the output voltage V1 of the storage unit 20 is reduced or recovered, the non-specific electrical device 5 currently in action is determined, and the threshold voltage Vth is set using the operation formula corresponding to the determined non-specific electrical device 5. Thus, the optimal threshold voltage Vth can be set according to the electrical device 5 currently in action.

[0095] (Variant 4)

[0096] In the above embodiment, the calculation formula (Formula 2) for obtaining the threshold voltage Vth assumes that the operations of the two systems 50 and 60 do not overlap, but it is also possible to assume that the operations of the two systems 50 and 60 overlap. The threshold voltage Vth in this case is given by the calculation formula of Formula 4.

[0097] Vth=(I_sbw+I_brake)×R+(I_sbw+I_brake)×dt / C+Vmin…Equation 4

[0098] (Summarize)

[0099] A backup power supply system (1) of a first embodiment includes a detection unit (31), a power storage unit (20), and a control unit (33). The detection unit (31) detects an abnormality in a power supply (4) that supplies power to a plurality of loads (5). When the detection unit (31) detects an abnormality in the power supply (4), the power storage unit (20) supplies power to the plurality of loads (5). The control unit (33) monitors the remaining power of the power storage unit (20), and when the remaining power of the power storage unit (20) is lower than a threshold power, limits the loads (5) to which the power storage unit (20) supplies power.

[0100] According to this structure, if the remaining power of the power storage unit (20) is lower than the threshold power, the load (5) that can be supplied with power by the power storage unit (20) is limited. Therefore, even if the remaining power of the power storage unit (20) decreases, power can be supplied to important loads (5) on a priority basis.

[0101] In the backup power supply system (1) of the second mode, in the first mode, the control unit (33) supplies power from the storage unit (20) to multiple loads (5) from the time when the detection unit (31) detects an abnormality in the power supply (4) until the remaining power of the storage unit (20) falls below a threshold power.

[0102] According to this structure, the freedom of operation of the load (5) can be suppressed from being reduced from the time when the detection unit (31) detects an abnormality in the power supply (4) to the time when the remaining power of the storage unit (20) falls below the threshold power (particularly immediately after the detection).

[0103] In the backup power supply system (1) of the third aspect, in the first or second aspect, the value of the output voltage (V1) of the storage unit (20) corresponding to the threshold power is set as the threshold voltage (Vth). The control unit (33) monitors the remaining power of the storage unit (20) by monitoring the output voltage (V1) of the storage unit (20), and determines that the remaining power of the storage unit (20) is lower than the threshold power if the output voltage (V1) of the storage unit (20) is lower than the threshold voltage (Vth).

[0104] According to this structure, since the remaining power of the power storage unit (20) is monitored by monitoring the output voltage (V1) of the power storage unit (20), expensive sensors such as current sensors are not required, and the remaining power of the power storage unit (20) can be monitored with a low-cost structure.

[0105] In the backup power supply system (1) of the fourth mode, in the third mode, if the remaining power of the storage unit (20) is lower than the threshold power, the control unit (33) supplies power from the storage unit (20) only to a specific load (e.g., a shift-by-wire system 50) among a plurality of loads (5).

[0106] According to this configuration, when the remaining power of the power storage unit (20) is lower than the threshold power, it is possible to ensure the supply of power to a specific load (50) among a plurality of loads (5).

[0107] In a backup power supply system (1) according to a fifth aspect, in the fourth aspect, the threshold electric quantity is an electric quantity that enables a specific load (50) to operate at least once.

[0108] According to this configuration, even when the remaining power of the power storage unit (20) is lower than the threshold power, power sufficient for a specific load (50) to operate at least once can be ensured.

[0109] In a backup power supply system (1) of a sixth aspect, in the fourth or fifth aspect, a load (60) other than a specific load (50) among a plurality of loads (5) is set as a non-specific load. In the output voltage (V1) of the power storage unit (20), the voltage amount reduced when the specific load (50) starts to operate is set as a reduced voltage amount (dV1), and the voltage amount restored when the non-specific load (60) ends to operate is set as a restored voltage amount (dY2). The threshold voltage (Vth) is set using a voltage difference obtained by subtracting the restored voltage amount (dY2) of the non-specific load (60) from the reduced voltage amount (dV1) of the specific load (50).

[0110] According to this structure, the threshold voltage (Vth) is set in consideration of the recovery voltage (dY2) generated when the non-specific load (60) ends its operation, so the threshold voltage (Vth) can be set with good accuracy. That is, the threshold voltage (Vth) can be set to an extremely low value.

[0111] In the backup power supply system (1) of the seventh aspect, in the fourth or fifth aspect, a load (60) other than a specific load (50) among a plurality of loads (5) is set as a non-specific load. In the output voltage (V1) of the power storage unit (20), the voltage amount reduced when the specific load (50) starts to operate is set as a reduced voltage amount (dV1), and the voltage amount restored when the non-specific load (60) ends to operate is set as a restored voltage amount (dV2). The threshold voltage (Vth) is set using the reduced voltage amount (dV1) related to the specific load (50) without subtracting the restored voltage amount (dV2) related to the non-specific load (60).

[0112] According to this configuration, since the threshold voltage (Vth) does not take into account the recovery voltage (dV2) generated when the operation of the non-specific load (60) ends, the threshold voltage (Vth) can be obtained by simple calculation.

[0113] In the backup power supply system (1) of the eighth aspect, in any one of the fourth to seventh aspects, the threshold voltage (Vth) is set using the value of the current (I_sbw) supplied to the specific load (50), the internal resistance (R) of the storage unit (20), and the capacity (C) of the storage unit (20).

[0114] According to this configuration, the threshold voltage (Vth) can be set using the value of the current (I_sbw) supplied to the specific load (50), the internal resistance (R) of the power storage unit (20), and the capacity (C) of the power storage unit (20).

[0115] In the backup power supply system (1) of the 9th mode, in any one of the 4th to 8th modes, the control unit (33) retains a plurality of calculation formulas for calculating the threshold voltage (Vth), selects one calculation formula from the plurality of calculation formulas according to a change in the output voltage (V1) of the storage unit (20), and uses the selected calculation formula to set the threshold voltage (Vth).

[0116] According to this configuration, the threshold voltage (Vth) can be set according to changes in the output voltage (V1) of the power storage unit (20).

[0117] In the backup power supply system (1) of a tenth aspect, in any one of the third to ninth aspects, the threshold voltage (Vth) is initially set.

[0118] According to this configuration, the processing load for calculating the threshold voltage (Vth) can be reduced.

[0119] In the backup power supply system (1) of the 11th mode, in any one of the 1st to 10th modes, there is further provided: a reporting unit (24) for reporting the content of the limitation to the user when the control unit (33) limits the load to which the power storage unit (20) provides power.

[0120] According to this configuration, the user can be informed of the content of the restriction.

[0121] A backup power supply system (1) according to a twelfth aspect is, in any one of the first to eleventh aspects, further comprising: a transformer circuit (21) for boosting an output voltage (V1) of the power storage unit (20) and outputting the boosted voltage to a plurality of loads (5).

[0122] According to this configuration, the output voltage (V1) of the power storage unit (20) can be transformed and supplied to the load (5).

[0123] In a backup power supply system (1) of a thirteenth aspect, in any one of the first to twelfth aspects, the power supply (4) and the plurality of loads (5) are mounted on a vehicle body.

[0124] According to this structure, the backup power supply system (1) can be applied to a vehicle.

[0125] A vehicle according to a fourteenth aspect comprises: a backup power supply system (1) according to any one of the first to thirteenth aspects; and a vehicle body on which the backup power supply system (1) is mounted.

[0126] According to this structure, a vehicle equipped with the backup power supply system (1) having the above-mentioned effects can be provided.

[0127] -Explanation of symbols-

[0128] 1 Backup power system

[0129] 5 Electrical equipment (load)

[0130] 20 Power storage unit

[0131] 21. Charging and discharging circuit (voltage conversion circuit)

[0132] 24 Reporting Department

[0133] 31 Abnormality detection unit (detection unit)

[0134] 33 Switch control unit (control unit)

[0135] 50 Shift-by-wire system (specific load)

[0136] 60 Braking system (non-specific load)

[0137] dV1 Voltage reduction amount

[0138] dV2 Recovery voltage

[0139] C Capacity

[0140] R Resistance

[0141] V1 Output voltage

[0142] Vth threshold voltage.

Claims

1. A backup power system, comprising: a detection unit that detects an abnormality of a power supply that supplies power to a plurality of loads; a power storage unit that supplies power to the plurality of loads when the detection unit detects an abnormality in the power supply; and a control unit that monitors the remaining power of the power storage unit and limits the load to which the power storage unit provides power if the remaining power of the power storage unit is lower than a threshold power. The value of the output voltage of the power storage unit corresponding to the threshold electric quantity is set as a threshold voltage, The control unit monitors the remaining power of the power storage unit by monitoring the output voltage of the power storage unit, and determines that the remaining power of the power storage unit is lower than the threshold power if the output voltage of the power storage unit is lower than the threshold voltage. If the remaining power of the power storage unit is lower than the threshold power, the control unit supplies the power from the power storage unit only to a specific load among the plurality of loads. setting loads other than the specific load among the plurality of loads as non-specific loads, In the output voltage of the power storage unit, a voltage amount that is reduced when the specific load starts to operate is set as a reduced voltage amount, and a voltage amount that is restored when the non-specific load ends to operate is set as a restored voltage amount, The threshold voltage is set using a voltage difference obtained by subtracting the recovery voltage amount of the non-specific load from the reduced voltage amount of the specific load.

2. The backup power supply system according to claim 1, wherein: The control unit supplies electric power from the power storage unit to the plurality of loads from the time when the detection unit detects an abnormality in the power supply until the remaining amount of the power storage unit falls below the threshold amount of power.

3. The backup power supply system according to claim 1, wherein: The threshold power level is the power level at which the specific load can perform at least one operation.

4. The backup power supply system according to any one of claims 1 to 3, wherein: The threshold voltage is set using a value of a current supplied to the specific load, an internal resistance of the power storage unit, and a capacity of the power storage unit.

5. The backup power supply system according to any one of claims 1 to 3, wherein: The control unit holds a plurality of calculation formulas for calculating the threshold voltage, selects one calculation formula from the plurality of calculation formulas according to a change in the output voltage of the power storage unit, and sets the threshold voltage using the selected calculation formula.

6. The backup power supply system according to any one of claims 1 to 3, wherein: The threshold voltage is initially set.

7. The backup power supply system according to any one of claims 1 to 3, wherein: The backup power supply system further includes a reporting unit configured to report details of the limitation to a user when the control unit limits the load to which the power storage unit supplies electric power.

8. The backup power supply system according to any one of claims 1 to 3, wherein: The backup power supply system further includes a voltage conversion circuit configured to increase the output voltage of the power storage unit and output the voltage to the plurality of loads.

9. The backup power supply system according to any one of claims 1 to 3, wherein: The power source and the plurality of loads are mounted on a vehicle body.

10. A backup power system comprising: a detection unit that detects an abnormality of a power supply that supplies power to a plurality of loads; a power storage unit that supplies power to the plurality of loads when the detection unit detects an abnormality in the power supply; and a control unit that monitors the remaining power of the power storage unit and limits the load to which the power storage unit provides power if the remaining power of the power storage unit is lower than a threshold power. The value of the output voltage of the power storage unit corresponding to the threshold electric quantity is set as a threshold voltage, The control unit monitors the remaining power of the power storage unit by monitoring the output voltage of the power storage unit, and determines that the remaining power of the power storage unit is lower than the threshold power if the output voltage of the power storage unit is lower than the threshold voltage. If the remaining power of the power storage unit is lower than the threshold power, the control unit supplies the power from the power storage unit only to a specific load among the plurality of loads. setting loads other than the specific load among the plurality of loads as non-specific loads, In the output voltage of the power storage unit, a voltage amount that is reduced when the specific load starts to operate is set as a reduced voltage amount, and a voltage amount that is restored when the non-specific load ends to operate is set as a restored voltage amount, The threshold voltage is set using the reduced voltage amount associated with the specific load without subtracting the recovery voltage amount associated with the non-specific load.

11. The backup power supply system according to claim 10, wherein: The control unit supplies electric power from the power storage unit to the plurality of loads from the time when the detection unit detects an abnormality in the power supply until the remaining amount of the power storage unit falls below the threshold amount of power.

12. The backup power system according to claim 10, wherein: The threshold power level is the power level at which the specific load can perform at least one operation.

13. The backup power supply system according to any one of claims 10 to 12, wherein: The threshold voltage is set using a value of a current supplied to the specific load, an internal resistance of the power storage unit, and a capacity of the power storage unit.

14. The backup power supply system according to any one of claims 10 to 12, wherein: The control unit holds a plurality of calculation formulas for calculating the threshold voltage, selects one calculation formula from the plurality of calculation formulas according to a change in the output voltage of the power storage unit, and sets the threshold voltage using the selected calculation formula.

15. The backup power supply system according to any one of claims 10 to 12, wherein: The threshold voltage is initially set.

16. The backup power supply system according to any one of claims 10 to 12, wherein: The backup power supply system further includes a reporting unit configured to report details of the limitation to a user when the control unit limits the load to which the power storage unit supplies electric power.

17. The backup power supply system according to any one of claims 10 to 12, wherein: The backup power supply system further includes a voltage conversion circuit configured to increase the output voltage of the power storage unit and output the voltage to the plurality of loads.

18. The backup power supply system according to any one of claims 10 to 12, wherein: The power source and the plurality of loads are mounted on a vehicle body.

19. A vehicle comprising: The backup power supply system according to any one of claims 1 to 18; and The vehicle body is equipped with the backup power supply system.

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