Vehicle

Abstract

To optimize a power supply system in a vehicle as an electric vehicle having a motor as a drive source of wheels.SOLUTION: A vehicle is provided with a motor provided as a drive source of wheels, a first battery provided as a power source of the motor, accessories, a battery mounting section to which a second battery having a rated output voltage lower than that of the first battery can be detachably mounted, and a boosting section for boosting the output voltage of the second battery, and the vehicle is configured so that the second battery mounted in the battery mounting section can supply power to the accessories and to the first battery via the boosting section. When the charging rate of the first battery becomes a predetermined value or less, the power consumption of the auxiliary machines is estimated, and power supply from the second battery to the first battery is started on condition that at least the value of the power consumption is less than a threshold value.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present technology relates to a vehicle such as an electric vehicle equipped with a motor as a drive source for wheels, and more particularly to a technical field related to power supply control for a battery provided as a power source for the motor. [Background technology]

[0002] As a technology for controlling power supply to a battery in an electric vehicle, for example, Patent Documents 1 and 2 listed below disclose a technology for boosting the output voltage of a low-voltage battery for auxiliary equipment and supplying power to a high-voltage battery for driving a motor. In particular, Patent Document 1 listed below discloses a technology for supplying power from the low-voltage battery when the SOC (State Of Charge) of the high-voltage battery falls below a lower limit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-244875 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-154847 Summary of the Invention [Problem to be solved by the invention]

[0004] The present technology aims to optimize the power supply system of an electric vehicle having a motor as a drive source for the wheels. [Means for solving the problem]

[0005] The vehicle according to the present technology comprises a motor provided as a drive source for wheels, a first battery provided as a power source for the motor, auxiliary machinery, a battery mounting portion to which a second battery having a lower rated output voltage than the first battery can be detachably attached, and a boost unit that boosts the output voltage of the second battery, and is configured so that the second battery attached to the battery mounting portion can supply power to the auxiliary machinery and to the first battery via the boost unit. The vehicle also comprises one or more processors and a storage medium on which a program executed by the one or more processors is stored, the program including one or more instructions that cause the one or more processors to execute a power supply control process that, when the charging rate of the first battery falls below a predetermined value, estimates the power consumption of the auxiliary machinery, and, provided that at least the value of the power consumption is less than a threshold, starts supplying power from the second battery to the first battery. [Effects of the Invention]

[0006] According to the present technology, it is possible to optimize the power supply system of a vehicle that is an electric vehicle having a motor as a drive source for the wheels. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a diagram illustrating an example of a schematic internal configuration of a vehicle according to an embodiment; [Figure 2] FIG. 2 is a diagram illustrating an example of an electrical configuration related to power supply control according to the embodiment. [Figure 3] 10 is a flowchart of a process for monitoring the SOC of a first battery. [Figure 4] 10 is a flowchart of a process in which a required torque is monitored. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present technology will be described with reference to the accompanying drawings. FIG. 1 is a diagram showing an example of a schematic internal configuration of a vehicle 1 according to an embodiment. Note that FIG. 1 shows only the components related to the present technology among the various components of a vehicle 1 according to the embodiment.

[0009] The vehicle 1 according to the embodiment is configured as an electric vehicle equipped with a motor generator (MG) 2 as a drive source for the wheels. Specifically, the vehicle 1 in this example is configured as a battery electric vehicle (BEV) that does not have an engine as a drive source for the wheels.

[0010] In this example, the vehicle 1 is assumed to be a four-wheeled vehicle, but the vehicle 1 according to the embodiment may be any electric vehicle having at least two or more wheels.

[0011] The vehicle is provided with a high-voltage battery 3 as a power source for MG2, and an inverter 4 is also provided for MG2. When MG2 is powered, the inverter 4 outputs a drive voltage generated based on the input voltage from the high-voltage battery 3 to MG2, and when regenerating, charges the high-voltage battery 3 using the regenerated power from MG2. The rated output voltage of the high-voltage battery 3 is set to a high voltage, such as 200V or 400V.

[0012] The vehicle 1 also includes auxiliary equipment 5. The auxiliary equipment 5 broadly includes various electronic devices mounted on the vehicle, such as various ECUs (Electric Control Units) used to control various operations of the vehicle 1, meters, navigation devices, audio devices, air conditioners (air conditioning devices), seat heaters, lighting devices such as headlights, and the like. Here, the ECUs provided in vehicle 1 include a driving control ECU that controls the output torque and regenerative power of MG2 in response to accelerator and brake operation by the driver, a driving safety control ECU that controls the vehicle's driving stability such as ABS (Anti-lock Brake System) and ESC (Electronic Stability Control), a door ECU that controls the locking and unlocking of doors, a lighting ECU that controls lighting fixtures such as headlamps and turn signal lamps, an air conditioner ECU that controls the air conditioner, and a navigation ECU that controls navigation.

[0013] In the vehicle 1 of this embodiment, power is basically supplied to the auxiliary equipment 5 using the high-voltage battery 3 as a power source. Specifically, the vehicle 1 is provided with a DC / DC converter 6 having a step-down function, and the step-down function of this DC / DC converter 6 enables the output voltage of the high-voltage battery 3 to be stepped down and supplied to the auxiliary equipment 5. In this example, the rated input voltage of the accessories 5 is about 12V, and the DC / DC converter 6 steps down the output voltage of the high-voltage battery 3 to about 12V and outputs it to the accessories 5. The rated input voltage of the auxiliary equipment 5 may be, for example, about 24V, and is not limited to about 12V.

[0014] The control unit 7 is configured with a microcomputer having a CPU (Central Processing Unit), ROM (Read Only Memory), and RAM (Random Access Memory), and performs various controls of the vehicle 1 by the CPU executing various processes according to programs stored in the ROM. In this example, the control unit 7 is configured as one of various ECUs mounted on the vehicle, and corresponds to one type of the auxiliary machinery 5. In FIG. 1 (and FIG. 2, which will be described later), the auxiliary machinery 5 and the control unit 7 are shown separately for convenience of illustration.

[0015] The vehicle 1 of this embodiment also includes a battery mounting portion 8 configured to allow a low-voltage battery 10, which has a rated output voltage lower than that of the high-voltage battery 3, to be detachably mounted. In this embodiment, the low-voltage battery 10 is assumed to be a battery that can be attached to the vehicle 1 at any time by the user of the vehicle 1, such as a driver, for the purpose of extending the driving distance of the vehicle 1. For this reason, the battery mounting section 8 is configured to allow the low-voltage battery 10 to be mounted in a relatively easy manner. For example, rather than using a mounting method that requires tools, such as screws, a mounting method using a locking mechanism that does not require tools, such as a buckle, is employed.

[0016] In the vehicle 1 of the embodiment, when a low-voltage battery 10 is attached to the battery attachment portion 8, it is possible to supply power from the low-voltage battery 10 to the high-voltage battery 3. Specifically, in the vehicle 1 of this example, the DC / DC converter 6 has a boost function in addition to the above-mentioned step-down function, and when the low-voltage battery 10 is attached to the battery attachment portion 8, the output voltage of the low-voltage battery 10 can be boosted by the boost function, and power can be supplied to the high-voltage battery 3 with the boosted voltage.

[0017] In addition, in the vehicle 1 of the embodiment, when a low-voltage battery 10 is attached to the battery mounting portion 8, power supply from the high-voltage battery 3 to the auxiliary equipment 5 via the DC / DC converter 6 is stopped, and power supply to the auxiliary equipment 5 is performed from the low-voltage battery 10. The rated output voltage of the low-voltage battery 10 is approximately equal to the rated input voltage of the auxiliary equipment 5, specifically, approximately 12V in this example.

[0018] In this way, the vehicle 1 of the embodiment is configured so that power can be supplied from the high-voltage battery 3 to the auxiliary machinery 5, and therefore can be driven even if the low-voltage battery 10 is not attached.

[0019] Furthermore, since the vehicle 1 of the embodiment can be additionally fitted with a low-voltage battery 10, the driving distance of the vehicle 1 can be extended even in situations where power cannot be supplied from an external power supply device, such as when there are no power supply facilities nearby.

[0020] Furthermore, in the vehicle 1 of the embodiment, when the low-voltage battery 10 is installed, power supply from the high-voltage battery 3 to the auxiliary equipment 5 is stopped and power supply from the low-voltage battery 10 to the auxiliary equipment 5 is started, thereby preventing the occurrence of transformation loss. The transformation loss here refers to the power loss that occurs when the DC / DC converter 6 steps down the voltage. By preventing the occurrence of transformation loss, the efficiency of power supply to the auxiliary equipment 5 can be improved.

[0021] FIG. 2 is a diagram showing an example of an electrical configuration related to power supply control of this embodiment. Specifically, Figure 2 shows the high-voltage battery 3, auxiliary equipment 5, control unit 7, and low-voltage battery 10 shown in Figure 1, as well as an example of the internal configuration of the DC / DC converter 6 and a connector unit 11 for electrically connecting the low-voltage battery 10 to the vehicle 1.

[0022] As shown in the figure, the DC / DC converter 6 includes a step-down unit 6a, a step-up unit 6b, a first switch unit SW1, a second switch unit SW2, and a control circuit 6c. The step-down unit 6a steps down the input voltage to the input terminal Tid to obtain a stepped-down voltage at the output terminal Tod. The booster 6b boosts the input voltage to the input terminal Tiu to obtain a boosted voltage at the output terminal Tou.

[0023] The first switch section SW1 and the second switch section SW2 are each configured as a three-terminal switch having a first terminal t1, a second terminal t2, and a third terminal t3, and are configured to selectively select the connection destination of the first terminal t1 from the second terminal t2 and the third terminal t3.

[0024] In the first switch section SW1, the first terminal t1 is connected to the high-voltage battery 3, the second terminal t2 is connected to the input terminal Tid of the voltage step-down section 6a, and the third terminal t3 is connected to the output terminal Tou of the voltage step-up section 6b. In addition, in the second switch section SW2, the first terminal t1 is connected to the connection point between the auxiliary equipment 5 and the connector section 11, the second terminal t2 is connected to the output terminal Tod of the voltage step-down section 6a, and the third terminal t3 is connected to the input terminal Tiu of the voltage step-up section 6b.

[0025] When the second terminal t2 is selected in both the first switch section SW1 and the second switch section SW2, the output voltage of the high-voltage battery 3 can be stepped down by the step-down section 6a and supplied to the connection point between the auxiliary equipment 5 and the connector section 11. In addition, when the third terminal t3 is selected in both the first switch section SW1 and the second switch section SW2, the output voltage of the low-voltage battery 10 can be boosted by the boost section 6b and supplied to the high-voltage battery 3.

[0026] The control circuit 6c is configured to include, for example, an IC (Integrated Circuit), and controls the operation of the step-down unit 6a and the step-up unit 6b, and controls the first switch unit SW1 and the second switch unit SW2.

[0027] The connector 11 has at least a positive terminal and a negative terminal for power supply. Here, the low-voltage battery 10 may have a configuration including a power storage unit such as a battery cell, for example a lithium-ion battery unit, and a microcomputer that performs various processes related to charging and discharging the power storage unit. In this case, the connector 11 is formed with signal terminals for communicating various signals in addition to the positive and negative terminals.

[0028] To clarify, the connector section 11 has a connector on the vehicle 1 side and a connector on the low-voltage battery 10 side, and when these connectors are mated together, an electrical connection is made between the low-voltage battery 10 side and the vehicle 1 side.

[0029] Here, in this specification, when we say "attaching" the low-voltage battery 10, it is meant to be a concept that includes the attachment of such a connector, in other words, a concept that includes even electrical connection.

[0030] The control unit 7 controls the power supply to the auxiliary devices 5 and the power supply to the high-voltage battery 3 . Specifically, when the SOC (State Of Charge) of the high-voltage battery 3 falls below a predetermined value (hereinafter referred to as "threshold THh"), the control unit 7 estimates the power consumption of the auxiliary equipment 5 and performs a power supply control process to start supplying power from the low-voltage battery 10 to the high-voltage battery 3, provided that the value of the power consumption is at least less than the threshold THa.

[0031] Here, the power consumption of the auxiliary devices 5 can be estimated based on the total current consumption of each load unit belonging to the auxiliary devices 5, such as various ECUs, an air conditioner, a seat heater, etc. This total current consumption can be detected as the output current value of the second battery 10.

[0032] By performing the above-described power supply control process, when the power consumption of the auxiliary equipment 5 is equal to or greater than the threshold value THo, that is, when the power required by the auxiliary equipment 5 is large, power supply from the low-voltage battery 10 to the high-voltage battery 3 is not performed. This prevents the auxiliary equipment 5 from running out of power, which would cause the vehicle 1 to become unable to run.

[0033] Furthermore, as part of the power supply control process described above, even when the required torque of MG2 is equal to or greater than a predetermined value (hereinafter referred to as "threshold value THt"), the control unit 7 estimates the power consumption of the auxiliary equipment 5 and starts supplying power from the low-voltage battery 10 to the high-voltage battery 3, provided that the value of the power consumption is at least less than the threshold value THa. Specifically, even if the SOC of the high-voltage battery 3 is not below the threshold THh, when the required torque of the MG2 is above the threshold THt, the control unit 7 performs control to start supplying power from the low-voltage battery 10 to the high-voltage battery 3, provided that the power consumption of the auxiliary equipment 5 is below the threshold THo.

[0034] This makes it possible to supply power from the low-voltage battery 10 to the high-voltage battery 3 in response to a case where the output of the MG2 (the output of the motor) is predicted to increase. Therefore, it is possible to prevent the acceleration performance of the vehicle 1 from being reduced due to a lack of driving force from the MG2.

[0035] For clarity, the required torque indicates a required value of the output torque of MG2, and is calculated by the above-mentioned cruise control ECU in response to accelerator operation.

[0036] Furthermore, in this embodiment, in addition to the prohibition condition related to the power consumption of the auxiliary machinery 5, a prohibition condition related to the fitting of the connector 11 is defined as a prohibition condition for supplying power from the low-voltage battery 10 to the high-voltage battery 3. Specifically, when the connector 11 is in a semi-fitted state, power is not supplied from the low-voltage battery 10 to the high-voltage battery 3 even if the execution conditions based on the SOC and required torque of the high-voltage battery 3 are met.

[0037] For this reason, in this example, when the SOC of the high-voltage battery 3 falls below the threshold value THh or when the required torque rises above the threshold value THt, the control unit 7 determines whether the power consumption of the auxiliary equipment 5 is above the threshold value THo and whether the connector unit 11 is in a semi-fitted state, and starts supplying power from the low-voltage battery 10 to the high-voltage battery 3, provided that the power consumption of the auxiliary equipment 5 is below the threshold value THo and the connector unit 11 is not in a semi-fitted state but in a fitted state.

[0038] Here, whether or not the connector portion 11 is in a semi-fitted state can be detected based on fluctuations (amount of change per unit time) in the voltage between the positive and negative terminals and the current flowing through the positive terminal of the connector portion 11. For example, if the magnitude of the fluctuations exceeds a predetermined magnitude and the frequency is equal to or greater than a predetermined frequency, it can be determined that the connector portion 11 is in a semi-fitted state. Alternatively, if the connector portion 11 has the above-mentioned signal terminals for communication, the determination of whether or not the connector is in a partially mated state may be made based on the presence or absence, frequency, etc. of interruptions in communication.

[0039] If the connector part 11 is only partially fitted, there is a risk of an arc occurring between the terminals on the low-voltage battery 10 side and the vehicle 1 main body side. In particular, since a voltage boost is required when supplying power from the low-voltage battery 10 to the high-voltage battery 3, there is a risk of fire, etc., if such an arc occurs. As described above, by preventing power supply from the low-voltage battery 10 to the high-voltage battery 3 when the connector portion 11 is in a semi-fitted state, it is possible to prevent the occurrence of an arc and improve safety.

[0040] Furthermore, in this example, when the control unit 7 determines that the connector unit 11 is in a semi-fitted state, it performs processing to maintain a state in which power is not supplied from the low-voltage battery 10 to the high-voltage battery 3 during the driving cycle in which the determination was made. In other words, when it determines that the connector unit 11 is in a semi-fitted state, power supply from the low-voltage battery 10 to the high-voltage battery 3 is prohibited thereafter until the end of the current driving cycle. Here, a driving cycle refers to a unit of driving, and is a concept that one cycle is from when the driver gets into the vehicle to when he finishes driving. The start of one driving cycle could be, for example, the timing when the start button (activation button) of the vehicle 1 is operated. Alternatively, it could be the timing when the doors change from a locked state to an unlocked state. The end of one driving cycle could be the timing when the start button is operated again while the vehicle 1 is starting, or the timing when the doors are locked after the start button is operated again.

[0041] By maintaining the power supply prohibition state until the end of the driving cycle as described above, it becomes possible to prohibit power supply from the low-voltage battery 10 to the high-voltage battery 3 until it is estimated that the connector part 11 can be reconnected, and on the other hand, it becomes possible to allow power supply from the low-voltage battery 10 to the high-voltage battery 3 after the connector part 11 is reconnected. Therefore, it is possible to supply power from the low-voltage battery 10 to the high-voltage battery 3, thereby extending the travel distance and realizing assistance for the motor drive voltage, while also improving safety.

[0042] In the above, an example of estimating the power consumption of the auxiliary equipment 5 is given, in which the total value of the current consumption of each load unit belonging to the auxiliary equipment 5 is calculated. However, it is also possible to estimate the power consumption of the auxiliary equipment 5 by estimating only the load units with large power consumption. For example, it is possible to estimate the power consumption of the auxiliary equipment 5 by estimating only the load units with large power consumption. For example, it is possible to estimate the power consumption of the air conditioner, the seat heater, the electric pump for circulating the lubricating oil in the drivetrain, etc.

[0043] Another possible approach is to prohibit power supply from the low-voltage battery 10 to the high-voltage battery 3 when it is predicted that a load with high power consumption will be used. For example, when it is predicted from outside temperature information that an air conditioner or a seat heater will be used, it is possible to prevent power supply from the low-voltage battery 10 to the high-voltage battery 3. Alternatively, in a vehicle having an AC 100V outlet, it is possible to prevent power supply from the low-voltage battery 10 to the high-voltage battery 3 when an external device is connected to the outlet.

[0044] An example of a specific processing procedure to be executed by the control unit 7 in order to realize the power supply control method according to the above embodiment will be described with reference to the flowcharts of FIGS. FIG. 3 shows a process in which the SOC of the high-voltage battery 3 is monitored, and FIG. 4 shows a process in which the required torque is monitored. The control unit 7 starts the processes shown in FIGS. 3 and 4 in response to activation, and executes them in parallel. 3, before the low-voltage battery 10 is attached, the control unit 7 turns on the step-down function of the DC / DC converter 6 to supply power from the high-voltage battery 3 to the auxiliary equipment 5. The step-down function can be turned on by turning on the step-down unit 6a and selecting the second terminal t2 with both the first switch unit SW1 and the second switch unit SW2.

[0045] 3, in step S101, the control unit 7 determines whether the low-voltage battery 10 is attached. The attachment determination may be made, for example, by determining whether or not current is being supplied from the low-voltage battery 10 via the connector unit 11. Alternatively, the attachment determination may be made using, for example, a pressure-sensitive sensor provided in the connector on the vehicle 1 side, and the specific determination method is not particularly limited.

[0046] If it is determined in step S101 that the low-voltage battery 10 has been attached, the control unit 7 proceeds to step S102 and controls to turn off the DC / DC converter 6. As a result, in response to the attachment of the low-voltage battery 10, the power supply from the high-voltage battery 3 to the accessories 5 via the step-down unit 6a is stopped, and the power source for the accessories 5 is switched to the low-voltage battery 10.

[0047] In step S103 following step S102, the control unit 7 determines whether the SOC of the high-voltage battery 3 is equal to or less than the threshold value THh. If it is determined in step S103 that the SOC of the high-voltage battery 3 is not equal to or less than the threshold value THh, the control unit 7 proceeds to step S104 to determine whether the driving cycle has ended, and if it is determined that the driving cycle has not ended, the control unit 7 returns to step S103. By the processing of steps S103 and S104, the control unit 7 waits until the SOC of the high-voltage battery 3 becomes equal to or less than the threshold value THh or until the driving cycle ends. Note that the example of the end of the driving cycle has already been explained, so a duplicate explanation will be avoided.

[0048] If it is determined in step S103 that the SOC of the high-voltage battery 3 is equal to or lower than the threshold value THh, the control unit 7 proceeds to step S105 and determines whether a power supply prohibition flag is ON. The power supply prohibition flag indicates whether power supply from the low-voltage battery 10 to the high-voltage battery 3 is prohibited in the current driving cycle, depending on whether the connector unit 11 is in a semi-fitted state. The power supply prohibition flag is initially set to OFF, indicating a non-prohibited state, and is set to ON, indicating a prohibited state, in step S111, which will be described later.

[0049] If it is determined in step S105 that the power supply prohibition flag is not on, the control unit 7 proceeds to step S106 and estimates the power consumption of the auxiliary equipment 5. Note that the method for estimating the product power of the auxiliary equipment 5 has already been explained, so a duplicate explanation will be avoided.

[0050] In step S107 following step S106, the control unit 7 determines whether the estimated power consumption is equal to or greater than the threshold value THo, and if the power consumption is not equal to or greater than the threshold value THo, proceeds to step S108 to determine whether the connector part 11 is in a semi-fitted state.

[0051] If it is determined in step S108 that the connector unit 11 is not in a semi-fitted state, in other words, if it is determined that the connector unit 11 is in a fitted state, the control unit 7 proceeds to step S109 and performs a process to start supplying power from the low-voltage battery 10 to the high-voltage battery 3. That is, the control unit 7 issues an instruction to the control circuit 6c to turn on the boost function of the DC / DC converter 6. In response to this instruction, the control circuit 6c turns on the boost unit 6b and causes both the first switch unit SW1 and the second switch unit SW2 to select the third terminal t3. As a result, when the SOC of the high-voltage battery 3 drops below the threshold value THh, power supply from the low-voltage battery 10 to the high-voltage battery 3 begins, provided that the power consumption of the auxiliary equipment 5 is less than the threshold value THo and the connector part 11 is in a mated state rather than a semi-mated state.

[0052] In step S110 following step S109, the control unit 7 waits until the SOC of the high-voltage battery 3 exceeds the threshold value THh, and if the SOC exceeds the threshold value THh, returns the process to the previous step S102. As a result, the power supply from the low-voltage battery 10 to the high-voltage battery 3, which was started in step S109, is stopped in response to the SOC of the high-voltage battery 3 exceeding the threshold value THh.

[0053] If it is determined in step S107 that the estimated power consumption is equal to or greater than the threshold value THo, the control unit 7 returns to step S103. As a result, even if the SOC of the high-voltage battery 3 drops below the threshold value THh, power is not supplied from the low-voltage battery 10 to the high-voltage battery 3 if the power consumption of the accessories 5 is equal to or greater than the threshold value THo.

[0054] Furthermore, if it is determined in the previous step S108 that the connector section 11 is in a semi-fitted state, the control section 7 proceeds to step S111 to perform processing to turn on the power supply prohibition flag, and then returns to step S103. After the power supply prohibition flag is set to ON, even if it is determined in step S103 that the SOC of the high-voltage battery 3 is equal to or lower than the threshold value THh, the determination process in step S105 determines that the power supply prohibition flag is ON, and the process returns to step S103. As a result, after it is determined that the battery is in the half-fitted state, power is not supplied from the low-voltage battery 10 to the high-voltage battery 3 until the end of the driving cycle.

[0055] If it is determined in step S104 that the driving cycle has ended, the control unit 7 proceeds to step S112, where it turns off the power supply prohibition flag, and ends the series of processes shown in FIG.

[0056] Next, the processing in FIG. 4 will be described. In FIG. 4, the same steps as those already explained in FIG. 3 are denoted by the same step numbers, and detailed explanations thereof will be omitted.

[0057] In FIG. 4, in step S201, the control unit 7 determines whether or not the conditions that the SOC of the high-voltage battery 3 is greater than the threshold value THh and the required torque is equal to or greater than the threshold value THt are met. If it is determined in step S201 that the conditions that the SOC of the high-voltage battery 3 is greater than the threshold value THh and the required torque is greater than or equal to the threshold value THt are not met, the control unit 7 proceeds to step S104 to determine whether the driving cycle has ended, and if it is determined that the driving cycle has not ended, the control unit 7 returns to step S201. This causes the control unit 7 to wait until one of the following conditions is met: the SOC of the high-voltage battery 3 is greater than the threshold value THh and the required torque is greater than or equal to the threshold value THt, or the driving cycle has ended.

[0058] If it is determined in step S201 that the conditions that the SOC of the high-voltage battery 3 is greater than the threshold value THh and the required torque is greater than or equal to the threshold value THt are met, the control unit 7 proceeds to step S105 to determine whether the power supply prohibition flag is on.If the power supply prohibition flag is not on, the control unit 7 estimates the power consumption of the auxiliary equipment 5 in step S106, and then determines in the subsequent step S107 whether the estimated power consumption is greater than or equal to the threshold value THo.

[0059] If it is determined in step S107 that the estimated power consumption is not equal to or greater than the threshold value THo, the control unit 7 proceeds to step S108 to determine whether the connector portion 11 is in a semi-fitted state, and if the connector portion 11 is not in a semi-fitted state, the control unit 7 proceeds to step S109 to perform a process of starting power supply from the low-voltage battery 10 to the high-voltage battery 3.

[0060] In this way, even in the power supply control based on the required torque, the conditions for power supply execution are that the power consumption of the auxiliary machinery 5 is less than the threshold value THo and that the connector portion 11 is in a fitted state rather than a semi-fitted state.

[0061] In response to executing the processing of step S109, the control unit 7 proceeds to step S202 and waits until the required torque falls below the threshold value THt. If it is determined that the required torque falls below the threshold value THt, the control unit 7 turns off the DC / DC converter 6 in step S102 and returns to step S201.

[0062] In this way, the power supply from the low-voltage battery 10 to the high-voltage battery 3, which is started when the required torque becomes equal to or greater than the threshold value THt, is stopped when the required torque falls below the threshold value THt.

[0063] As shown in the figure, if it is determined in step S105 that the power supply prohibition flag is on, the process returns to step S201. As a result, even if the required torque is equal to or greater than the threshold value THt, if it is determined that the connector portion 11 is in a semi-fitted state, power supply from the low-voltage battery 10 to the high-voltage battery 3 is prohibited until the end of the current driving cycle.

[0064] Furthermore, if it is determined in step S107 that the power consumption of the auxiliary equipment 5 is equal to or greater than the threshold value THo, the process returns to step S201, and if it is determined in step S108 that the connector portion 11 is in a semi-fitted state, the power supply prohibition flag is turned on in step S111, and the process returns to step S201. As a result, even if the required torque is equal to or greater than the threshold value THt, if the power consumption of the auxiliary equipment 5 is equal to or greater than the threshold value THo or if the connector part 11 is in a semi-fitted state, power is not supplied from the low-voltage battery 10 to the high-voltage battery 3.

[0065] If the control unit 7 determines in step S104 that the driving cycle has ended, the process proceeds to step S112, where the power supply prohibition flag is turned off, and the series of processes shown in FIG. 4 is then completed.

[0066] Here, for the sake of explanation, an example has been given in which the processing relating to power supply control is executed by a single processor as an embodiment, but it is also possible that the processing may be shared and executed by a plurality of processors.

[0067] It should be noted that the present embodiment is not limited to the specific examples described above, and various modified configurations can be adopted. For example, in the above example, the power supply prohibition flag is turned off upon completion of the driving cycle, thereby permitting power supply in the next driving cycle. However, the condition for canceling the power supply prohibition state can also be other conditions, such as the re-installation of the low-voltage battery 10.

[0068] Although the above describes an example in which the present technology is applied to a BEV vehicle, the present technology can be widely and suitably applied to other electrically powered vehicles such as HEVs (Hybrid EVs) and PHEVs (Plug-in Hybrid EVs), etc. In particular, the present technology is suitable for vehicles that do not have a permanently installed auxiliary battery, such as a lead battery.

[0069] As described above, the vehicle (1) as an embodiment comprises a motor (MG2) provided as a drive source for the wheels, a first battery (high-voltage battery 3) provided as a power source for the motor, auxiliary equipment (5), a battery mounting section (8) to which a second battery (low-voltage battery 10) having a lower rated output voltage than the first battery can be detachably attached, and a boost section (6b) that boosts the output voltage of the second battery, and is configured so that the second battery attached to the battery mounting section can supply power to the auxiliary equipment and to the first battery via the boost section, and also comprises one or more processors (CPU of the control section 7) and a storage medium (ROM of the control section 7) on which a program executed by the one or more processors is stored, the program including one or more instructions. The instruction then causes one or more processors to execute a power supply control process that, when the charging rate of the first battery falls below a predetermined value, estimates the power consumption of the auxiliary equipment and starts supplying power from the second battery to the first battery, provided that the power consumption value is at least less than a threshold value. In the vehicle having the above configuration, by attaching the second battery to the attachment portion, it is possible to supply power from the second battery to the auxiliary equipment and also to supply power from the second battery to the first battery. When supplying power from the first battery to the auxiliary equipment, it is necessary to step down the output voltage of the first battery, which results in a transformation loss. However, by enabling power to be supplied to the auxiliary equipment from the second battery as described above, such a transformation loss can be prevented, and the power supply to the auxiliary equipment can be made more efficient. In the above-described vehicle, if the power consumption of the auxiliary equipment is greater than or equal to a threshold value, i.e., if the power required by the auxiliary equipment is large, power will not be supplied from the second battery to the first battery, thereby preventing the auxiliary equipment from running out of power and the vehicle from becoming unable to run. Therefore, according to the vehicle of the embodiment, it is possible to optimize the power supply system of the vehicle, which is an electric vehicle having a motor as a drive source for the wheels.

[0070] In addition, in the vehicle embodiment, in the power supply control process, even if the required torque of the motor becomes equal to or greater than a predetermined value, the power consumption of the auxiliary equipment is estimated, and power supply from the second battery to the first battery is started, provided that the power consumption value is at least less than a threshold value. This makes it possible to supply power from the second battery to the first battery in response to a case where the motor output is predicted to increase. Therefore, it is possible to prevent the vehicle's acceleration performance from decreasing due to a lack of driving force from the motor.

[0071] Furthermore, in the vehicle embodiment, in the power supply control process, when the charging rate of the first battery falls below a predetermined value, it is determined whether the connector portion that electrically connects the second battery is in a semi-fitted state, and power supply from the second battery to the first battery is started, provided that the power consumption value is less than a threshold value and the connector portion is in a fitted state rather than a semi-fitted state. If the connector portion is only partially engaged, there is a risk of an arc occurring between the terminals on the second battery side and the vehicle main body side, and in particular, since a voltage boost is required when supplying power from the second battery to the first battery, the occurrence of such an arc could lead to a risk of fire, etc. With the above configuration, it is possible to prevent power from being supplied from the second battery to the first battery when the connector portion is only partially engaged, thereby improving safety.

[0072] Furthermore, in a vehicle embodiment, the above-mentioned instructions cause one or more processors to execute processing to maintain a state in which power is not supplied from the second battery to the first battery during the driving cycle in which the determination is made, if the processor determines that the connector portion is in a semi-engaged state. This makes it possible to prohibit power supply from the second battery to the first battery until it is estimated that the connector portion can be reconnected, while on the other hand, after the connector portion has been reconnected, it becomes possible to allow power supply from the second battery to the first battery. Therefore, it is possible to extend the travel distance and realize assistance for the motor drive voltage by supplying power from the second battery to the first battery, while also improving safety.

[0073] In addition, in the vehicle embodiment, a step-down unit (same as 6a) is provided that steps down the output voltage of the first battery, and the above-mentioned instruction causes one or more processors to execute a process of supplying power from the first battery to the auxiliary equipment via the step-down unit when the second battery is not attached to the battery attachment portion, and stopping the power supply from the first battery to the auxiliary equipment when the second battery is attached to the battery attachment portion. This allows power to be supplied to the auxiliaries even if the second battery is not installed, making it possible to run the vehicle, and after the second battery is installed, power supply from the first battery to the auxiliaries via the step-down unit is stopped, preventing the occurrence of voltage transformation loss and thereby improving the efficiency of power supply to the auxiliaries. [Explanation of symbols]

[0074] 1 vehicle 2 MG (Motor Generator) 3 High Voltage Battery 4 inverters 5 Auxiliary equipment 6 DC / DC converters 7 Control Unit 8 Battery mounting section 10 Low voltage battery 11 Connector part 6a Step-down section 6b Booster section 6c Control circuit SW1 First switch SW2 Second switch section t1 first terminal t2 second terminal t3 third terminal Tid input terminal Tod output terminal Tiu input terminal Tou output terminal

Claims

1. a motor provided as a drive source for the wheels; a first battery provided as a power source for the motor; Auxiliary equipment and a battery mounting portion to which a second battery having a rated output voltage lower than that of the first battery can be detachably mounted; a booster unit that boosts the output voltage of the second battery, The second battery attached to the battery attachment portion is configured to be able to supply power to the auxiliary devices and to the first battery via the booster portion, one or more processors and a storage medium storing a program to be executed by the one or more processors; The program includes one or more instructions that cause the one or more processors to: When the charging rate of the first battery becomes equal to or lower than a predetermined value, power consumption of the auxiliary devices is estimated, and a power supply control process is executed to start power supply from the second battery to the first battery on condition that at least the value of the power consumption is less than a threshold value. vehicle.

2. In the power supply control process, Even when the required torque of the motor is equal to or greater than a predetermined value, the power consumption of the auxiliary devices is estimated, and power supply from the second battery to the first battery is started on the condition that the value of the power consumption is at least less than a threshold value. The vehicle of claim 1 .

3. In the power supply control process, When the charging rate of the first battery becomes equal to or lower than a predetermined value, it is determined whether a connector portion electrically connecting the second battery is in a semi-fitted state; On the condition that the power consumption value is less than a threshold value and the connector portion is in a mated state rather than a semi-mated state, power supply from the second battery to the first battery is started. The vehicle of claim 1 .

4. The instructions may cause the one or more processors to: When it is determined that the connector portion is in a semi-fitted state, a process is executed to maintain a state in which power is not supplied from the second battery to the first battery during the driving cycle in which the determination was made.

4. The vehicle of claim 3.

5. a step-down unit that steps down the output voltage of the first battery; The instructions may cause the one or more processors to: When the second battery is not attached to the battery attachment portion, power is supplied from the first battery to the auxiliary devices via the step-down unit, and in response to the second battery being attached to the battery attachment unit, a process is executed to stop the power supply from the first battery to the auxiliary devices. A vehicle according to any one of claims 1 to 4.

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