Auxiliary power supply unit and electric vehicle

Abstract

The present invention relates to an auxiliary power supply device and an electric vehicle. An auxiliary power supply device (20) comprises: an auxiliary power supply (21); and an auxiliary power supply control unit (22), which switches the mode of the auxiliary power supply (21) to an output mode or a non-output mode when power is output from a main power supply (11) to a drive motor (40). The auxiliary power supply control unit (22) is configured to switch the mode to a non-output mode when the required power value required by the drive motor (40) is equal to or less than a predetermined power value, and to switch the mode to an output mode when the required power value is greater than a predetermined power value, wherein the predetermined power value is set to a value less than the outputtable power, the outputtable power being the power that can be output from the main power supply (11).

Description

Technical Field

[0001] The invention relates to an auxiliary power supply device and an electric vehicle. Background Art

[0002] Japanese Unexamined Patent Application Publication No. 2017-225241 (JP 2017-225241A) discloses an electric vehicle including an auxiliary battery as a main power source and a backup power source. In this electric vehicle, the main power source outputs power to a drive motor so that the drive motor rotates a wheel. The main power source is a rechargeable battery and is charged by power from a generator. In this electric vehicle, when the power output from the main power source to the drive motor is stopped, the backup power source outputs power to the drive motor instead of the main power source. Summary of the invention

[0003] In the above-mentioned electric vehicle, the power output from the main power supply may become greater than the power required to drive the motor. In this case, the power consumption in the main power supply increases compared to the case where the power required to drive the motor is output from the main power supply. It cannot be said that measures are disclosed in JP 2017-225241 A to reduce the power consumption in the main power supply of the electric vehicle.

[0004] A first aspect of the present invention relates to an auxiliary power supply device configured to be installed in an electric vehicle, comprising: a drive motor configured to generate a driving force required for the electric vehicle to travel; and a main power supply configured to output power to the drive motor, thereby causing the electric vehicle to travel. The auxiliary power supply device comprises: an auxiliary power supply configured to output power along the flow of power from the main power supply to the drive motor; and an auxiliary power supply control unit configured to switch the mode of the auxiliary power supply to an output mode or a non-output mode when power is output from the main power supply to the drive motor, the output mode being a mode in which power is output from the auxiliary power supply, and the non-output mode being a mode in which power is not output from the auxiliary power supply. The auxiliary power supply control unit is configured to switch the mode to the non-output mode when the required power value required for the drive motor is equal to or less than a predetermined power value, and to switch the mode to the output mode when the required power value is greater than a predetermined power value, the predetermined power value being set to a value less than the outputtable power, the outputtable power being the power that can be output from the main power supply.

[0005] With the above configuration, even when the power that can be output from the main power source is sufficiently large, the auxiliary power source can output power according to a value that makes the value of the power output from the main power source exceed the predetermined power. Therefore, even when an event occurs in which the required power value required to drive the motor suddenly increases when the power that can be output from the main power source is sufficiently large, the power consumption of the main power source can be reduced.

[0006] In the above auxiliary power supply device, in the non-output mode, the auxiliary power supply can be charged with the power output from the main power supply. In the above configuration, the auxiliary power supply can be charged while the main power supply is outputting power to the drive motor. Therefore, the power supply path from the main power supply to the drive motor is also used as a part of the charging path of the auxiliary power supply. This helps to simplify the power supply path.

[0007] In the above-mentioned auxiliary power supply device, in the non-output mode, the auxiliary power supply can be charged with the power generated by the generator based on the operation of the engine. In the above-mentioned configuration, because the auxiliary power supply is charged with the power generated by the generator, the auxiliary power supply can be continuously charged while the engine is continuously driven (i.e., the engine is continuously operated).

[0008] A second aspect of the present invention relates to an electric vehicle comprising: an auxiliary power supply device; a main power supply device comprising a main power supply and a main power supply control unit, the main power supply control unit being configured to control the output of electric power from the main power supply to a drive motor; and a drive motor.

[0009] With the above configuration, in the output mode, the auxiliary power supply outputs power from the main power supply to the drive motor along the flow of power. Therefore, the power output from the main power supply can be reduced compared to the case where only the main power supply outputs power to the drive motor. Therefore, even in the case where the power output from the main power supply becomes greater than the required power value required for the drive motor, the auxiliary power supply outputs power according to a value that makes the required power value exceed the predetermined power value. It is possible to provide an electric vehicle with reduced power consumption.

[0010] The electric vehicle may further include: an engine; and a generator configured to generate electric power based on operation of the engine. At least one of the main power source and the auxiliary power source may be charged using the electric power generated by the generator.

[0011] By the above configuration, at least one of the main power supply and the auxiliary power supply is charged with the power generated by the generator. Therefore, it is possible to provide an electric vehicle in which at least one of the main power supply and the auxiliary power supply is continuously charged while the engine is continuously driven (i.e., while the engine is continuously running).

[0012] The auxiliary power supply device and the electric vehicle according to the above-described aspect of the present invention reduce power consumption in the main power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like reference numerals represent like elements, and in which:

[0014] Figure 1 FIG. 2 schematically illustrates a configuration of an electric vehicle including an auxiliary power supply device.

[0015] Figure 2 is a flowchart of a process executed by the auxiliary power supply control unit according to the first embodiment.

[0016] Figure 3 is a graph illustrating how the output of electric power and the charging of electric power change in the comparative example.

[0017] Figure 4 : is a graph illustrating how the output of electric power and the charging of electric power change in the first embodiment.

[0018] Figure 5 is a graph schematically illustrating an example of transition among the non-charging and non-output mode, the charging and non-output mode, and the output mode.

[0019] Figure 6 is a flowchart of a process performed by an auxiliary power control unit according to the second embodiment; and

[0020] Figure 7 A configuration of an electric vehicle including an auxiliary power supply device according to another embodiment is schematically illustrated. DETAILED DESCRIPTION

[0021] A first embodiment in which an auxiliary power supply device is applied to an electric vehicle will be described. Figure 1 As shown in FIG. 1 , an electric vehicle 1 includes a main power supply device 10, an auxiliary power supply device 20, a drive circuit 30, a drive motor 40, a gear mechanism 50, an engine 60, and a generator 70. The vehicle 1 can travel using the drive motor 40 as a drive source. The drive motor 40 is driven by the power output from the main power supply device 10. The electric vehicle 1 is an extended-range electric vehicle.

[0022] The output shaft of the drive motor 40 is coupled to the gear mechanism 50. The drive motor 40 generates a driving force required for the electric vehicle 1 to travel. The gear mechanism 50 is connected to left and right drive shafts 51. One end of each drive shaft 51 is connected to the gear mechanism 50, and the other end is connected to a corresponding one of the wheels 52. The driving force of the drive motor 40 is transmitted to the wheel 52 via the gear mechanism 50 and the drive shaft 51. The main power supply device 10 is connected to the auxiliary power supply device 20, the auxiliary power supply device 20 is connected to the drive circuit 30, and the drive circuit 30 is connected to the drive motor 40.

[0023] The engine 60 is connected to the generator 70. The engine 60 is used for power generation performed by the generator 70. In the first embodiment, the engine 60 is a gasoline engine driven using gasoline as fuel. The generator 70 is connected to the main power supply device 10. The generator 70 generates electricity based on the driving force of the engine 60. The electricity generated by the generator 70 is output to the main power supply device 10. The electricity generated by the generator 70 is used to charge the main power supply device 10.

[0024] The main power supply device 10 includes a main power supply 11 and a main power supply control unit 12. The main power supply 11 is a power supply that can be charged with power and can discharge the power. The main power supply 11 is, for example, a lithium-ion battery. The main power supply 11 outputs power to the drive motor 40 as a power supply object to be supplied with power. The main power supply control unit 12 is connected to an external control device via a communication line such as a controller area network (CAN) communication, and obtains information output from the external control device. The external control device calculates the required power value W as this information, which is the power required for the drive motor 40, and outputs the required power value W to the main power supply control unit 12 via the CAN communication. The main power supply control unit 12 controls the operation of the drive circuit 30 based on the required power value W to control the power output from the main power supply 11 to the drive motor 40. The main power supply control unit 12 obtains information such as the remaining power of the main power supply 11. The main power supply control unit 12 outputs a signal for starting the engine 60 to the engine 60 so that the remaining power of the main power supply 11 does not become less than its lower limit. The lower limit of the remaining power of the main power supply 11 is a lower limit value of the remaining power that suppresses the progress of the degradation of the main power supply 11 or suppresses the reduction of the maximum capacity of the main power supply 11 by outputting power from the main power supply 11. The lower limit of the remaining power of the main power supply 11 is set based on experiments or the like. The main power supply control unit 12 starts the driving (operation) of the engine 60 by outputting a signal for starting the engine 60 to the engine 60. Thus, the generator 70 generates power for charging based on the driving force of the engine 60. When a sufficient amount of power remains in the main power supply 11, the main power supply control unit 12 stops the driving (operation) of the engine 60 by outputting a signal for stopping the engine 60 to the engine 60.

[0025] The auxiliary power supply device 20 includes an auxiliary power supply 21, an auxiliary power supply control unit 22, a switch 23, and a boost circuit 24. The auxiliary power supply 21 is a power supply that can be charged with power and can discharge power. The auxiliary power supply 21 is, for example, a lithium ion capacitor. The advantages of the lithium ion capacitor are that the lithium ion capacitor has high heat resistance, long life, good charging and discharging performance, and high energy density, and is highly safe. In particular, compared with lithium ion batteries, lithium ion capacitors have the characteristics that lithium ion capacitors can be charged and discharged more times and have a longer life. The auxiliary power supply 21 is charged with power output from the main power supply 11 so that the remaining power of the auxiliary power supply 21 does not become less than its lower limit. The lower limit of the remaining power of the auxiliary power supply 21 is a lower limit value of the remaining power that suppresses the progress of the deterioration of the auxiliary power supply 21 or limits the reduction of the maximum capacity of the auxiliary power supply 21 by outputting power from the auxiliary power supply 21. The lower limit of the remaining power of the auxiliary power supply 21 is set based on experiments, etc. One end of the auxiliary power supply 21 is connected to the drive circuit 30. The auxiliary power source 21 outputs power along the flow of power from the main power source 11 to the drive motor 40 by outputting the power to the drive circuit 30 .

[0026] The auxiliary power control unit 22 is connected to the main power control unit 12 via a communication line such as CAN communication, and obtains the required power value W from the main power control unit 12. The auxiliary power control unit 22 is an electronic control unit (ECU) including a processor, etc., and the main power control unit 12 is also an ECU including a processor, etc. When the main power supply 11 outputs power to the drive motor 40, the auxiliary power control unit 22 switches the operation mode of the auxiliary power supply 21 to an output mode or a non-output mode. The output mode is a mode in which the auxiliary power supply 21 outputs power, and the non-output mode is a mode in which the auxiliary power supply 21 does not output power. The auxiliary power control unit 22 controls the state of the switch 23 to switch the mode of the auxiliary power supply 21 to an output mode or a non-output mode. The non-output mode includes a charging and non-output mode and a non-charging and non-output mode. The charging and non-output mode is a non-output mode for charging the auxiliary power supply 21. The non-charging and non-output mode is a non-output mode in which the auxiliary power supply 21 is not charged.

[0027] The switch 23 includes a plurality of switch elements. The switch 23 is configured so that its first end is connected to the main power supply 11, and its second end is switchably connected to the first supply path L1 or the second supply path L2. The first supply path L1 is a power supply path from the main power supply 11 to the drive motor 40, which connects the main power supply 11 and the drive circuit 30. The third supply path L3 is connected to the connection point P1 on the first supply path L1. The auxiliary power supply 21 is connected to the connection point P1 on the first supply path L1 through the third supply path L3. The boost circuit 24 is arranged on the third supply path L3. The boost circuit 24 increases the voltage of the input power. When the second end of the switch 23 is connected to the first supply path L1 and a non-charging and non-output mode in which the auxiliary power supply 21 is not charged is established, the main power supply 11 and the drive circuit 30 are connected through the first supply path L1, and the power supply along the third supply path L3 connecting the auxiliary power supply 21 and the first supply path L1 is cut off. When the second end of the switch 23 is connected to the first supply path L1 and the charging and non-output mode for charging the auxiliary power supply 21 is established, conduction is established to supply power along the third supply path L3, which connects the auxiliary power supply 21 and the first supply path L1. That is, in the charging and non-output mode, the portion of the first supply path L1 between the connection point P1 and the main power supply 11 is also used as a part of the charging path. That is, the first supply path L1 is also used as a part of the charging path. When the second end of the switch 23 is connected to the first supply path L1 and the charging and non-output mode of the auxiliary power supply 21 is established, the lower potential side of the auxiliary power supply 21 is connected to the third supply path L3 and its higher potential side is grounded. Because the first supply path L1 and the third supply path L3 are connected in parallel, the voltage of the power flowing through the first supply path L1, that is, the voltage of the same potential as the voltage of the power from the main power supply 11 is input to the boost circuit 24. The boost circuit 24 boosts the voltage at the same potential as the voltage of the power from the main power supply 11, and outputs the boosted voltage to the auxiliary power supply 21. The connection state of the auxiliary power source 21 is switched by switching the state of the switching element of the switch 23 .

[0028] The second supply path L2 is a power supply path that connects the main power supply 11 and the auxiliary power supply 21. The fourth supply path L4 is connected to a connection point P2 between a connection point P1 on the first supply path L1 and the drive circuit 30. The auxiliary power supply 21 is connected to the connection point P2 on the first supply path L1 through the fourth supply path L4. When the second end of the switch 23 is connected to the second supply path L2, the main power supply 11 and the auxiliary power supply 21 are connected in series through the first supply path L1 and the second supply path L2. When the second end of the switch 23 is connected to the second supply path L2, the auxiliary power supply 21 and the drive circuit 30 are connected through the fourth supply path L4 and the first supply path L1.

[0029] To establish the non-charging and non-output mode or the charging and non-output mode of the auxiliary power supply 21, the auxiliary power control unit 22 connects the second end of the switch 23 to the first supply path L1. In the output mode of the auxiliary power supply 21, the auxiliary power control unit 22 connects the second end of the switch 23 to the second supply path L2.

[0030] The drive circuit 30 is a known circuit including two switching elements for each phase (U phase, V phase, W phase) of the drive motor 40. The drive motor 40 is driven based on the power received via the drive circuit 30. The driving force from the drive motor 40 is transmitted to the wheel 52 via the gear mechanism 50 and the drive shaft 51, and thus the wheel 52 is rotated.

[0031] Will refer to Figure 2 The flow of processing executed by the auxiliary power supply control unit 22 is described. Figure 2 The processing flow illustrated in FIG. 1 is realized by the auxiliary power supply control unit 22 that performs periodic processing in each control cycle.

[0032] Figure 2 The processing is performed by the auxiliary power supply control unit 22. This processing starts when the starting switch for starting the electric vehicle 1 is turned on, and ends when the starting switch is turned off. Here, it is assumed that the mode of the auxiliary power supply 21 is a non-charging and non-output mode when the processing starts. In this case, the second end of the switch 23 is connected to the first supply path L1, and the power supply along the third supply path L3 is cut off. The required power value W calculated by the external control device is also output to the main power supply control unit 12. Therefore, the main power supply 11 is executed while outputting power to the drive circuit 30. Figure 2 The main power supply 11 is charged with the power generated by the generator 70 so that the remaining power of the main power supply 11 does not become less than its lower limit. The main power supply 11 is charged so as to have a certain amount of remaining power, which allows the auxiliary power supply control unit 22 to perform Figure 2 The process shown in FIG.

[0033] like Figure 2 As shown in , the auxiliary power supply control unit 22 determines whether the auxiliary power supply voltage Vc is lower than the charging lower limit voltage Vs (step S1). The auxiliary power supply voltage Vc is the voltage of the power from the auxiliary power supply 21, and the charging lower limit voltage Vs is the lower limit of the voltage of the auxiliary power supply 21. The auxiliary power supply voltage Vc indicates the remaining power of the auxiliary power supply 21, and the charging lower limit voltage Vs indicates the lower limit of the remaining power of the auxiliary power supply 21. The auxiliary power supply control unit 22 stores the charging lower limit voltage Vs therein.

[0034] When the auxiliary power supply voltage Vc is lower than the charging lower limit voltage Vs (yes in step S1), the auxiliary power supply control unit 22 performs charging and non-output control (step S2). After step S2, the routine performed by the auxiliary power supply control unit 22 returns to step S1. Charging and non-output control is a control that switches the mode of the auxiliary power supply 21 to a charging and non-output mode. In this case, the second end of the switch 23 is connected to the first supply path L1, so that the main power supply 11 and the drive circuit 30 are connected through the first supply path L1, and conduction is established to supply power along the third supply path L3. In charging and non-output control, the auxiliary power supply control unit 22 uses the boost circuit 24 to increase the voltage of the power from the main power supply 11, and applies the increased voltage to the auxiliary power supply 21 to charge the auxiliary power supply 21.

[0035] When the auxiliary power supply voltage Vc is equal to or higher than the charging lower limit voltage Vs (No in step S1), the auxiliary power supply control unit 22 determines whether the required power value W is greater than the predetermined power value P (step S3). The predetermined power value P is a threshold value for determining whether to perform output control. The predetermined power value P is experimentally calculated based on factors such as a reduction level indicating to what extent the power consumption in the main power supply 11 needs to be reduced, the maximum output capacity of the auxiliary power supply 21, and the maximum output capacity of the main power supply 11. The predetermined power value P is set to a value that is less than the outputtable power (upper limit) of the power that can be output from the main power supply 11. In the first embodiment, the predetermined power value P is set to, for example, about half of the outputtable power of the power that can be output from the main power supply 11. The auxiliary power supply control unit 22 stores the predetermined power value P therein.

[0036] When the required power value W is greater than the predetermined power value P (yes in step S3), the auxiliary power control unit 22 performs output control (step S4). Output control is a control that switches the mode of the auxiliary power supply 21 to the output mode. In the output control, the auxiliary power control unit 22 switches the state of the switch 23 to switch the mode of the auxiliary power supply 21 to the output mode. In this case, the second end of the switch 23 is connected to the second supply path L2, so that the auxiliary power supply 21 and the main power supply 11 are connected in series. Therefore, power is output from the main power supply 11 to the drive circuit 30, and power is also output from the auxiliary power supply 21 to the drive circuit 30 to increase the voltage of the power output from the main power supply 11 to the drive circuit 30 so that the required power value W is met. As described above, the auxiliary power supply 21 outputs power along the flow of power from the main power supply 11 to the drive motor 40, and outputs the combined power obtained by combining the power output from the main power supply 11 and the power output from the auxiliary power supply 21 toward the drive circuit 30.

[0037] After step S4, the routine performed by the auxiliary power control unit 22 returns to step S1. When the required power value W is equal to or less than the predetermined power value P (no in step S3), the auxiliary power control unit 22 performs non-charging and non-output control (step S5). Non-charging and non-output control is a control that switches the mode of the auxiliary power supply 21 to a non-charging and non-output mode. In the non-charging and non-output control, the auxiliary power control unit 22 switches the state of the switch 23 to switch the mode of the auxiliary power supply 21 to a non-charging and non-output mode. In this case, the second end of the switch 23 is connected to the first supply path L1, so that the main power supply 11 and the drive circuit 30 are connected through the first supply path L1, and the power supply along the third supply path L3 is cut off. Therefore, the main power supply 11 outputs power to the drive motor 40, and the auxiliary power supply 21 does not output power to the drive circuit 30.

[0038] After step S5, the routine executed by the auxiliary power control unit 22 returns to step S1. When the electric vehicle 1 is turned off by turning off the start switch Figure 2 The processing shown in the figure ends by interruption.

[0039] The operation in this embodiment will be described. Figure 3 is a graph illustrating a comparative example, and Figure 4 is a graph illustrating the first embodiment. The electric vehicle of the comparative example does not include Figure 1 The auxiliary power supply device 20 shown in FIG. 1 is configured so that only the main power supply 11 outputs power to the drive motor 40. Figure 3 In the graph, each peak on the power supply side indicates that the power corresponding to the peak is output from the main power supply 11, and each peak on the charging side indicates that the main power supply 11 is charged with the power corresponding to the peak.

[0040] like Figure 3 As shown in , in the comparative example, even when the required power value W is greater than the predetermined power value P, the main power supply 11 outputs all the power corresponding to the required power value W. Therefore, if the main power supply 11 outputs power greater than the required power value W, the power consumption in the main power supply 11 (i.e., the consumed power) increases compared to the case where the main power supply 11 outputs power according to the required power value W. In this case, due to the increase in power consumption in the main power supply 11, the main power supply 11 needs to be charged more frequently so that the remaining power of the main power supply 11 is not less than its lower limit. Therefore, it is necessary to start the engine 60 more frequently so that the generator 70 generates power for charging based on the driving force of the engine 60.

[0041] like Figure 1 and Figure 4As shown in, in the first embodiment, when the required power value W is greater than the predetermined power value P, the auxiliary power control unit 22 connects the second end of the switch 23 to the second supply path L2 to switch the mode of the auxiliary power supply 21 to the output mode. Therefore, the main power supply 11 and the auxiliary power supply 21 are connected in series. Therefore, the main power supply 11 outputs power to the drive circuit 30, and the auxiliary power supply 21 also outputs power to the drive circuit 30, so that the voltage of the power output from the main power supply 11 to the drive circuit 30 is increased. The auxiliary power supply 21 outputs power corresponding to a value that makes the required power value W greater than the predetermined power value P (in other words, the auxiliary power supply 21 outputs power corresponding to a value that makes the required power value W exceed the predetermined power value P, that is, the auxiliary power supply 21 outputs power corresponding to the difference between the required power value W and the predetermined power value P). That is, the main power supply 11 and the auxiliary power supply 21 output power corresponding to the required power value W. As a result of making the required power value W greater than the predetermined power value P, the auxiliary power supply 21 outputs power corresponding to the difference between the required power value W and the predetermined power value P. Figure 4 The value of the predetermined power value P shown in FIG. 1 is the power output from the auxiliary power supply 21, which varies depending on the situation. Therefore, the auxiliary power supply 21 can output a power equal to or greater than the required power value W. Figure 4 . Therefore, power equal to or greater than the required power value W can be output to the drive circuit 30. However, in the present embodiment, since the main power supply 11 and the auxiliary power supply 21 output power corresponding to the required power value W, the possibility that power equal to or greater than the required power value W is output can be reduced compared to the case where only the main power supply 11 outputs power corresponding to the required power value W.

[0042] Figure 5 Schematically illustrates examples of transitions between a non-charging and non-output mode, a charging and non-output mode, and an output mode. Figure 1 and Figure 5 As shown in , when the required power value W is equal to or less than the predetermined power value P, the auxiliary power supply control unit 22 performs non-charging and non-output control to switch the mode of the auxiliary power supply 21 to the non-charging and non-output mode. In this case, the main power supply 11 outputs all the power corresponding to the required power value W.

[0043] When the required power value W is greater than the predetermined power value P, the auxiliary power supply control unit 22 performs output control to switch the mode of the auxiliary power supply 21 to the output mode. In this case, the main power supply 11 outputs power corresponding to the predetermined power value P in the power according to the required power value W, and the auxiliary power supply 21 outputs power according to a value that makes the required power value W greater than the predetermined power value P.

[0044] When the auxiliary power supply voltage Vc is lower than the charging lower limit voltage Vs, the auxiliary power supply control unit 22 performs charging and non-output control to switch the mode of the auxiliary power supply 21 to the charging and non-output mode. Because the remaining power of the auxiliary power supply 21 decreases during the output control, this charging control is usually performed after the output control. In this charging and non-output control, the auxiliary power supply 21 is charged with the power output from the main power supply 11.

[0045] The effect of the first embodiment will be described. In the output mode established when the required power value W is greater than the predetermined power value P, the auxiliary power supply 21 outputs power along the flow of power from the main power supply 11 to the drive motor 40. Therefore, even when the power output from the main power supply 11 is sufficiently large, the auxiliary power supply 21 can output power according to a value that makes the power from the main power supply 11 exceed the predetermined power value P. Therefore, even when an event occurs that causes the required power value W required by the drive motor 40 to suddenly increase in a situation where the power that can be output from the main power supply 11 is sufficiently large, the power in the main power supply 11 can be reduced.

[0046] Since the power consumption in the main power source 11 can be reduced, the main power source 11 needs to be charged less frequently so that the remaining power of the main power source 11 does not become less than its lower limit. Therefore, the generator 70 needs to generate power for less frequent charging. Compared with the comparative example, the electric vehicle 1 in which the power consumption in the main power source 11 is reduced can be provided. Therefore, the fuel efficiency of the electric vehicle 1 is improved.

[0047] In the charging and non-output mode, the auxiliary power source 21 can be charged while the main power source 11 outputs power to the drive motor 40. Therefore, the first supply path L1 also serves as a part of the charging path of the auxiliary power source 21. This helps to simplify the power source path.

[0048] If the auxiliary power supply 21 is provided on the first power supply path L1 and the drive circuit 30 and the auxiliary power supply 21 are connected in series, the voltage of the power output from the main power supply 11 in the charging and non-output mode is divided into the voltage of the power flowing into the auxiliary power supply 21 for charging and the voltage of the power output to the drive circuit 30. That is, for example, the voltage of the power of the auxiliary power supply 21 may be lower than the power output from the main power supply 11. In this regard, in the charging and non-output mode of the present embodiment, since the first supply path L1 and the third supply path power supply path L3 are connected in parallel, the voltage of the power flowing into the third supply path L3 is the same as the voltage of the power output from the main power supply 11. Since the auxiliary power supply 21 is a capacitor, the power for charging the auxiliary power supply 21 increases in proportion to the input voltage. Compared with the case where the auxiliary power supply 21 is provided on the first supply path L1, the auxiliary power supply 21 is more efficiently charged in the charging and non-output mode.

[0049] In the charging and non-output mode, a voltage of the same potential as the voltage of the power from the main power supply 11 is applied to the booster circuit 24 on the third power supply path L3. The voltage applied to the auxiliary power supply 21 is obtained by boosting the voltage of the power from the main power supply 11 using the booster circuit 24 (in other words, the voltage of the power from the main power supply 11 is boosted by the booster circuit 24, and then, the boosted voltage is applied to the auxiliary power supply 21). Since the auxiliary power supply 21 is a capacitor, the power used to charge the auxiliary power supply 21 increases in proportion to the input voltage. Since the auxiliary power supply 21 is charged based on the voltage boosted by the booster circuit 24, the power used to charge the auxiliary power supply 21 is larger than the case where the auxiliary power supply 21 is charged with the voltage of the power from the main power supply 11. Therefore, the auxiliary power supply 21 is more efficiently charged during the charging and non-output control than when the booster circuit 24 is not provided.

[0050] Since the main power source 11 is charged with the power generated by the generator 70, the electric vehicle 1 can be provided in which the main power source 11 is continuously charged while the engine 60 is continuously driven (while the engine 60 is continuously operated). Since the auxiliary power source 21 is charged with the power from the main power source 11, the electric vehicle 1 in which the auxiliary power source 21 can be charged can be provided.

[0051] exist Figure 2 In the embodiment, step S1 is first executed to determine whether to perform charging and non-output control. Therefore, when the output control of step S4 is executed, the auxiliary power supply 21 is basically already charged. Therefore, even if the determination result of step S3 is yes and the output control should be executed, the possibility that there is no remaining power in the auxiliary power supply 21 can be reduced.

[0052] A second embodiment will be described in which the auxiliary power supply device is applied to an electric vehicle. The following will mainly describe the differences from the first embodiment. In the second embodiment, the auxiliary power supply control unit 22 executes Figure 6 Instead of the treatment shown in Figure 2 The processing shown in .

[0053] like Figure 6 As shown in FIG. 1 , the auxiliary power source control unit 22 determines whether the required power value W is greater than the predetermined power value P (step S11 ). Step S11 is the same or similar processing as step S3 .

[0054] When the required power value W is greater than the predetermined power value P (Yes in step S11), the auxiliary power supply control unit 22 determines whether the auxiliary power supply voltage Vc is higher than the output control lower limit threshold value Vt (step S11). Step S12 is a process for preventing a situation where output control of switching the mode of the auxiliary power supply 21 to the output mode is performed when power cannot be output from the auxiliary power supply 21 to the drive circuit 30. The output control lower limit threshold value Vt is a lower limit value of the auxiliary power supply voltage Vc for suppressing the progress of the degradation of the auxiliary power supply 21 or suppressing the reduction of the maximum capacity of the auxiliary power supply 21 by performing output control. The output control lower limit threshold value Vt is set to a value lower than the charging lower limit voltage Vs. The auxiliary power supply control unit 22 stores the output control lower limit threshold value Vt therein.

[0055] When the auxiliary power supply voltage Vc is higher than the output control lower limit threshold value Vt (Yes in step S12), the auxiliary power supply control unit 22 performs output control (step S13). The output control in step S13 is the same or similar processing as the output control in step S4. After step S13, the routine executed by the auxiliary power supply control unit 22 returns to step S11.

[0056] When the auxiliary power supply voltage Vc is equal to or lower than the output control lower limit threshold value Vt (No in step S12), the auxiliary power supply control unit 22 performs non-charging and non-output control (step S14). The non-charging and non-output control in step S14 is the same or similar processing as the non-charging and non-output control in step S5. After step S14, the routine executed by the auxiliary power supply control unit 22 returns to step S11.

[0057] When the required power value W is equal to or less than the predetermined power value P (NO in step S11), the auxiliary power control unit 22 determines whether the auxiliary power voltage Vc is lower than the charging lower limit voltage Vs (step S15). Step S15 is the same or similar processing as step S1.

[0058] When the auxiliary power supply voltage Vc is lower than the charging lower limit voltage Vs (Yes in step S15), the auxiliary power supply control unit 22 performs charging and non-output control (step S16). The charging and non-output control of step S16 is a process similar to the charging and non-output control of step S2. After step S16, the routine of the auxiliary power supply control unit 22 returns to step S11.

[0059] When the auxiliary power supply voltage Vc is equal to or higher than the charging lower limit voltage Vs (No in step S15), the auxiliary power supply control unit 22 performs non-charging and non-output control (step S17). The non-charging and non-output control in step S17 is the same or similar processing as the non-charging and non-output control in step S14 and the non-charging and non-output control in step S5.

[0060] When the electric vehicle 1 is turned off by turning off the start switch, the interruption ends. Figure 6 According to the second embodiment described above, even when the auxiliary power control unit 22 executes Figure 6 When the processing shown in is performed, the effects similar to those of the first embodiment can also be obtained.

[0061] The above embodiment may be modified as follows. As long as no technical contradiction occurs, the following other embodiments may be combined. In the charging and non-output mode, the auxiliary power supply 21 is charged with the power output from the main power supply 11. However, the present invention is not limited thereto. For example, similar to the main power supply 11, the auxiliary power supply 21 may be charged with the power generated by the generator 70. The main power supply 11 may not be charged with the power generated by the generator 70, but only the power generated by the generator 70 may be charged with the auxiliary power supply 21.

[0062] Can be Figure 6 The charging and non-output control is performed in step S14. The boost circuit 24 may not be provided on the third supply path L3. The switch 23 may be provided outside the auxiliary power supply device 20.

[0063] The required power value W from the external control device may be input to both the main power supply control unit 12 and the auxiliary power supply control unit 22 , or may be input only to the auxiliary power supply control unit 22 .

[0064] like Figure 7 As shown in FIG. 1 , the generator 70 may be connected to the drive circuit 30 through the fifth supply path L5. While the engine 60 is driven, the power generated by the generator 70 is input to the drive circuit 30 via the fifth supply path L5. While the engine 60 is driven, the drive motor 40 is driven based on the power input via the fifth supply path L5.

[0065] When the required power value W is greater than the predetermined power value P, the auxiliary power source 21 outputs power corresponding to a value that makes the required power value W greater than the predetermined power value P. However, the relationship between the power output from the auxiliary power source 21 and the predetermined power value P is not limited thereto. When the required power value W is greater than the predetermined power value P, the auxiliary power source 21 may output power less than the power corresponding to the value that makes the required power value W greater than the predetermined power value P, instead of outputting all the power corresponding to the value that makes the required power value W greater than the predetermined power value P. Alternatively, the auxiliary power source 21 may output power greater than the power corresponding to the value that makes the required power value W greater than the predetermined power value P. The power output from the auxiliary power source 21 may be appropriately set.

[0066] The required power value W is not limited to the value obtained from the external control device. The power input to the drive circuit 30 may be detected by a sensor, and the detected value may be used as the required power value. A peak clipping circuit may be provided, and in the output mode, the peak clipping circuit may limit the power output from the main power supply 11 to a predetermined power value P. In this case, the power output from the main power supply 11 is not determined by the situation, and is limited to the predetermined power value P by the circuit configuration.

[0067] Although a lithium ion battery is used as the main power source 11 , the main power source 11 may be any secondary power source that can be charged with electricity and discharged, and may be other secondary batteries such as a lithium ion polymer battery, a nickel hydride battery, a nickel cadmium battery, or a lead storage battery.

[0068] Although a lithium ion capacitor is used as the auxiliary power source 21, the auxiliary power source 21 may be any power source that can be charged with electricity and can be discharged, and may be another capacitor such as an electric double layer. The auxiliary power source 21 may be a secondary battery such as a lithium ion battery, a lithium ion polymer battery, a nickel metal hydride battery, a nickel cadmium battery, or a lead storage battery.

[0069] The drive motor 40 may be a three-phase brushless motor or a brushed motor. The engine 60 is not limited to a gasoline engine, and may be another engine such as a diesel engine, an engine using hydrogen fuel, or an engine using a fuel cell.

[0070] The electric vehicle 1 is an extended-range electric vehicle. However, the electric vehicle 1 may be an electric vehicle in which at least one of the main power source 11 and the auxiliary power source 21 is charged by plug-in charging. That is, the electric vehicle 1 may be an electric vehicle not provided with the engine 60 and the generator 70.

Claims

1. An auxiliary power supply device (20), the auxiliary power supply device (20) being configured to be installed in an electric vehicle, the electric vehicle comprising a drive motor (40) and a main power supply (11), the drive motor (40) being configured to generate a driving force required for the electric vehicle to travel, the main power supply (11) being configured to output electric power to the drive motor (40) so that the electric vehicle travels, the auxiliary power supply device (20) comprising: a first supply path (L1) connecting the main power source and the drive motor; an auxiliary power supply (21) configured to output the electric power along the flow of the electric power from the main power supply (11) to the drive motor (40); a third supply path (L3) connecting the auxiliary power supply device to the first supply path; a switch (23) for switching the power output from the main power supply between the first supply path in which the main power supply and the auxiliary power supply are connected in parallel via the third supply path and a second supply path (L2) in which the main power supply is directly connected in series to the auxiliary power supply; as well as an auxiliary power supply control unit (22), the auxiliary power supply control unit (22) being configured to: when the power is output from the main power supply (11) to the drive motor (40), switch the mode of the auxiliary power supply (21) to an output mode or a non-output mode, the output mode being a mode in which the main power supply and the auxiliary power supply are connected in series via the switch and the power is output from the auxiliary power supply (21), and the non-output mode being a mode in which the main power supply and the auxiliary power supply are connected in parallel via the switch and the power is not output from the auxiliary power supply (21), The auxiliary power control unit (22) is configured to switch the mode to the non-output mode when the required power value required by the drive motor (40) is equal to or less than a predetermined power value, and to switch the mode to the output mode when the required power value is greater than the predetermined power value, wherein the predetermined power value is set to a value smaller than the outputtable power, and the outputtable power is the power that can be output from the main power supply (11).

2. The auxiliary power supply device (20) according to claim 1, wherein: In the non-output mode, the auxiliary power source (21) is charged using the electric power output from the main power source (11).

3. The auxiliary power supply device (20) according to claim 1, wherein: In the non-output mode, the auxiliary power source (21) is charged using the electric power generated by the generator (70) based on the operation of the engine (60).

4. The auxiliary power supply device according to claim 1, wherein: The non-output mode includes a charging mode and a non-charging mode, and In the charging mode, a portion of the electric power output from the main power source is used to charge the auxiliary power source.

5. The auxiliary power supply device according to claim 1, wherein: The auxiliary power source is a lithium ion capacitor.

6. An electric vehicle comprising: The auxiliary power supply device (20) according to claim 1; A main power supply device (10), the main power supply device (10) comprising the main power supply (11) and a main power supply control unit (12), the main power supply control unit (12) being configured to control output of the electric power from the main power supply (11) to the drive motor (40); as well as The driving motor (40).

7. The electric vehicle according to claim 6, further comprising: Engine (60); as well as a generator (70) configured to generate the electric power based on the operation of the engine (60), The electric power generated by the generator (70) is used to charge at least one of the main power source (11) and the auxiliary power source (21).

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