Vehicle

Abstract

A vehicle according to the present invention comprises: a vehicle battery; a motor generator that is capable of inputting and outputting electric power to and from the vehicle battery and an external battery which is externally provided; a circuit unit that connects the motor generator to the vehicle battery and the external battery; and a control unit that controls the vehicle battery and the external battery. When electric power is input to and output from both the vehicle battery and the external battery, the control unit restricts input and output of electric power to and from one of the vehicle battery and the external battery on the basis of a load applied to the circuit unit.

Description

vehicle

[0001] The present invention relates to the technical field of vehicles.

[0002] BACKGROUND ART Conventionally, vehicles have been proposed that are driven by a motor supplied with power from a main battery mounted on the vehicle body and a sub-battery that is detachable from the vehicle body (see, for example, Patent Document 1).

[0003] Japanese Patent Application Publication No. 11-341608

[0004] In the above-mentioned vehicle, the sub-battery is used first, and then the main battery is used after the sub-battery is depleted. Therefore, no safety measures have been taken to ensure safety when both the main battery and the sub-battery are used simultaneously.

[0005] The present invention has been made in view of the above circumstances, and has as its object to improve power performance while maintaining safety.

[0006] A vehicle according to one embodiment of the present invention comprises a vehicle battery, a motor generator capable of inputting and outputting power to and from the vehicle battery and an external battery provided externally, a circuit unit connecting the vehicle battery, the external battery, and the motor generator, and a control unit controlling the vehicle battery and the external battery, wherein when there is input and output of power to both the vehicle battery and the external battery, the control unit limits the input and output of power to one of the vehicle battery and the external battery based on the load on the circuit unit.

[0007] According to the present invention, it is possible to maintain safety while improving power performance.

[0008] FIG. 1 is a diagram showing an outline of the configuration of a charging system. FIG. 2 is a diagram explaining the functional configuration of a control unit. FIG. 3 is a diagram showing the flow of power when driving a motor generator in normal mode. FIG. 4 is a flowchart showing the control flow of a trailer battery in normal mode. FIG. 5 is a diagram showing the flow of power when driving a motor generator in boost mode. FIG. 6 is a diagram explaining processing in boost mode. FIG. 7 is a diagram explaining processing in boost mode. FIG. 8 is a graph showing smoke generation characteristics.

[0009] 1. Vehicle System Configuration Fig. 1 is a diagram showing an outline of the configuration of a vehicle system 1. As shown in Fig. 1, the vehicle system 1 includes a vehicle 2 and a trailer 3. The vehicle 2 and the trailer 3 are mechanically and electrically connected via a connection unit 4. The trailer 3 is detachable from the vehicle 2.

[0010] The vehicle 2 is an electric vehicle equipped with a motor generator 11 , an inverter 12 , a vehicle battery 13 and a control unit 14 .

[0011] The motor generator 11 is a power source, such as a three-phase AC motor, that drives the vehicle 2. The motor generator 11 generates driving force using electric power supplied via an inverter 12 from one or both of the vehicle battery 13 and a trailer battery 22 (described later), and transmits the driving force to the drive wheels to drive the vehicle 2.

[0012] The motor generator 11 also generates electric power by performing regenerative operation. The electric power generated by the regenerative operation of the motor generator 11 can be supplied to the vehicle battery 13 and the trailer battery 22 via the inverter 12.

[0013] The inverter 12 converts the DC current input from the vehicle battery 13 and the trailer battery 22 into three-phase AC current and outputs it to the motor generator 11. Furthermore, when the motor generator 11 performs regenerative operation, the inverter 12 converts the AC current input from the motor generator 11 into DC current and outputs it to the vehicle battery 13 and the trailer battery 22.

[0014] The vehicle battery 13 is a so-called high-voltage secondary battery, and is mounted, for example, under the floor. The vehicle battery 13 stores electricity to be supplied to the motor generator 11. The vehicle battery 13 can be charged by regenerative driving by the motor generator 11. The vehicle battery 13 may also be charged by power supplied from the trailer battery 22.

[0015] The control unit 14 is configured by one or more computers such as ECUs (Electronic Control Units), and controls the entire vehicle 2 and trailer 3. The control unit 14 will be described in detail later.

[0016] The trailer 3 does not have a power source and is towed by the vehicle 2. The trailer 3 is equipped with a converter 21 and a trailer battery 22.

[0017] The converter 21 is a DC (Direct Current) / DC converter. The converter 21 converts the voltage of the direct current input from the trailer battery 22 and outputs the converted voltage to the vehicle 2 (motor generator 11, vehicle battery 13). The converter 21 also converts the voltage of the direct current input from the vehicle 2 (motor generator 11) and outputs the converted voltage to the trailer battery 22.

[0018] The trailer battery 22 is a so-called high-voltage secondary battery. The trailer battery 22 stores electricity to be supplied to the motor generator 11 and the vehicle battery 13. The trailer battery 22 can be charged by regenerative driving by the motor generator 11.

[0019] In the vehicle system 1 configured as described above, the trailer battery 22 connected to the vehicle 2 can supply more power to the motor generator 11 than in the vehicle 2 alone, and the cruising distance that can be traveled on a single charge can be extended. On the other hand, in the vehicle system 1, the vehicle 2 must tow the trailer 3, which increases the overall weight and reduces the power performance.

[0020] Therefore, in the vehicle system 1, by simultaneously supplying the motor generator 11 with both the power output from the vehicle battery 13 and the power output from the trailer battery 22, it is possible to increase the driving force of the motor generator 11 and improve the power performance of the vehicle system 1.

[0021] FIG. 2 is a diagram illustrating the functional configuration of the control unit 14. As shown in FIG. 2, the control unit 14 functions as a mode setting unit 31, a state detection unit 32, and a power supply control unit 33. The mode setting unit 31 sets one of a plurality of control modes to control the motor generator 11, the vehicle battery 13, and the trailer battery 22. In this embodiment, the control modes include a normal mode and a boost mode. Note that the control modes are not limited to these, and other modes may be provided. The state detection unit 32 detects the states of the vehicle battery 13 and the trailer battery 22. The detected states include SOC (State of Charge), temperature, input / output current values, voltage values, etc., as well as available input power (hereinafter referred to as available input power) and available output power (hereinafter referred to as available output power) calculated from these values. The power supply control unit 33 controls the motor generator 11, the vehicle battery 13, and the trailer battery 22 based on the control mode set by the mode setting unit 31 and the states of the motor generator 11 and the trailer battery 22 detected by the state detection unit 32.

[0022] 2. Normal Mode Fig. 3 is a diagram showing the flow of power when driving the motor generator 11 in the normal mode. Note that in Fig. 3, the flow of power is indicated by arrows.

[0023] In the normal mode, power is exchanged between the motor generator 11 and the vehicle battery 13, and power is exchanged between the vehicle battery 13 and the trailer battery 22. On the other hand, in the normal mode, power is not exchanged between the motor generator 11 and the trailer battery 22.

[0024] 3, when the motor generator 11 is driven, power is supplied from the vehicle battery 13 to the motor generator 11 via the inverter 12. When the SOC of the vehicle battery 13 is low, power is supplied from the trailer battery 22 to the vehicle battery 13 via the converter 21, and the vehicle battery 13 is charged.

[0025] Therefore, the motor generator 11 generates driving force using the electric power supplied from the vehicle battery 13, and therefore the driving force that can be generated is smaller than in the boost mode described below.

[0026] Furthermore, when the motor generator 11 performs regenerative operation, the electric power generated by the motor generator 11 is supplied to the vehicle battery 13 via the inverter 12 but is not supplied to the trailer battery 22 .

[0027] Figure 4 is a flowchart showing the flow of control of the trailer battery 22 in normal mode. The process shown in Figure 4 is performed when normal mode is set by the state detection unit 32. When the process of controlling the trailer battery 22 is started, in step S1 the state detection unit 32 detects the state of the vehicle battery 13. Here, the SOC and inputtable power of the vehicle battery 13 are detected. Next, in step S2 the power supply control unit 33 obtains an upper limit threshold for the SOC that has been set in advance by the user. The upper limit threshold indicates the upper limit of the SOC desired by the user.

[0028] In step S3, the power supply control unit 33 determines whether the SOC of the vehicle battery 13 is equal to or lower than the upper threshold. If the SOC of the vehicle battery 13 is not equal to or lower than the upper threshold (No in step S3), the process shown in Fig. 4 ends. On the other hand, if the SOC of the vehicle battery 13 is equal to or lower than the upper threshold (Yes in step S3), the state detection unit 32 detects the state of the trailer battery 22 in step S4. Here, the SOC and available output power of the trailer battery 22 are detected.

[0029] Next, in step S5, the state detection unit 32 calculates the power being output from the vehicle battery 13, i.e., the power consumption of the vehicle battery 13. Furthermore, in step S6, the power supply control unit 33 calculates the power that can be supplied from the trailer battery 22 to the vehicle battery 13 (supply power) based on the available input power and power consumption of the vehicle battery 13 and the available output power of the trailer battery 22. Then, in step S7, the power supply control unit 33 controls the trailer battery 22 to supply the supply power calculated in step S6 to the vehicle battery 13.

[0030] 3. Boost Mode Fig. 5 is a diagram showing the flow of power when driving the motor generator 11 in boost mode. Note that in Fig. 5, the flow of power is indicated by arrows.

[0031] In the boost mode, power is exchanged between the motor generator 11 and the vehicle battery 13, and power is exchanged between the motor generator 11 and the trailer battery 22. At this time, power can be supplied to the motor generator 11 from the vehicle battery 13 and the trailer battery 22 simultaneously, and power can be supplied from the motor generator 11 to the vehicle battery 13 and the trailer battery 22 simultaneously.

[0032] Therefore, a large current may flow through the circuit unit 15 (harness) provided between both the vehicle battery 13 and the trailer battery 22 and the motor generator 11. If a large current flows through the circuit unit 15, the circuit unit 15 may heat up and cause fire or smoke. Therefore, the vehicle system 1 performs the following process to prevent fire or smoke from occurring in the circuit unit 15. Note that the circuit unit 15 may include not only a harness but also electronic components.

[0033] 6 and 7 are diagrams illustrating the processing in the boost mode. When the mode setting unit 31 sets the boost mode, the control unit 14 performs the processing shown in Fig. 6 and 7. In step S11, the state detection unit 32 detects the state of the vehicle battery 13. Here, the state detection unit 32 detects the SOC, available input power, and available output power of the vehicle battery 13.

[0034] Subsequently, in step S12, the state detection unit 32 detects the state of the trailer battery 22. Here, the state detection unit 32 detects the SOC, the available input power, and the available output power of the trailer battery 22.

[0035] In step S13, the power supply control unit 33 calculates the total inputtable power (hereinafter referred to as the total inputtable power) by adding together the inputtable power of the vehicle battery 13 detected in step S11 and the inputtable power of the trailer battery 22 detected in step S12. In addition, in step S14, the power supply control unit 33 calculates the total outputtable power (hereinafter referred to as the total outputtable power) by adding together the outputtable power of the vehicle battery 13 detected in step S11 and the outputtable power of the trailer battery 22 detected in step S12.

[0036] In step S15, the power supply control unit 33 determines whether the accelerator pedal has been operated. If the accelerator pedal has not been operated (No in step S15), the process proceeds to step S20. On the other hand, if the accelerator pedal has been operated (Yes in step S15), in step S16, the power supply control unit 33 sets a target acceleration based on the accelerator pedal operation amount (depression amount) and the speed (vehicle speed) of the vehicle 2. The power supply control unit 33 then calculates the driving force of the motor generator 11 that will achieve the set target acceleration. The power supply control unit 33 also calculates the electric power (driving power) required to output the calculated driving force from the motor generator 11. Note that if the calculated driving power exceeds the total available output power, the driving power is limited to the total available output power.

[0037] In the following step S17, the power supply control unit 33 determines whether the available output power of the vehicle battery 13 is equal to or greater than the drive power. If the available output power of the vehicle battery 13 is equal to or greater than the drive power (Yes in step S17), the drive power required to output the calculated drive force to the motor generator 11 can be supplied by the vehicle battery 13 alone. Therefore, in step S18, the power supply control unit 33 controls the vehicle battery 13 to output drive power to the motor generator 11 and stops the output of power from the trailer battery 22. In other words, the power supply control unit 33 preferentially uses the vehicle battery 13 to drive the motor generator 11.

[0038] On the other hand, if the available output power of the vehicle battery 13 is not equal to or greater than the drive power (No in step S17), the drive power for outputting the calculated drive force to the motor generator 11 cannot be provided by the vehicle battery 13 alone. Therefore, in step S19, the power supply control unit 33 controls the vehicle battery 13 to output the available output power, and also controls the trailer battery 22 to output the power (shortfall) obtained by subtracting the available output power of the vehicle battery 13 from the drive power. This allows the vehicle system 1 to drive the motor generator 11 using the power of the vehicle battery 13 and the trailer battery 22 simultaneously. In other words, the vehicle system 1 can improve drive performance.

[0039] As shown in FIG. 7 , in step S20, the power supply control unit 33 determines whether the brake pedal has been operated. If the brake pedal has not been operated (No in step S20), the process proceeds to step S25. On the other hand, if the brake pedal has been operated (Yes in step S20), in step S21, the power supply control unit 33 sets a target deceleration based on the amount of brake pedal operation (depression amount) and the speed (vehicle speed) of the vehicle 2. Then, the power supply control unit 33 calculates the braking force of the motor generator 11 that will achieve the set target deceleration. The power supply control unit 33 also calculates the power that can be regenerated by the motor generator 11 using the calculated braking force (regenerative power). If the regenerative power calculated here exceeds the total inputtable power, the regenerative power is limited to the total inputtable power.

[0040] In the next step S22, the power supply control unit 33 determines whether the inputtable power of the vehicle battery 13 is equal to or greater than the regenerated power. If the inputtable power of the vehicle battery 13 is equal to or greater than the regenerated power (Yes in step S22), all of the power regenerated by the motor generator 11 can be used to charge the vehicle battery 13. Therefore, in step S23, the power supply control unit 33 controls the vehicle battery 13 to input all of the power regenerated by the motor generator 11, and to stop the input of power to the trailer battery 22. In other words, the power supply control unit 33 charges the vehicle battery 13 with priority.

[0041] On the other hand, if the inputtable power of the vehicle battery 13 is not equal to or greater than the regenerated power (No in step S22), not all of the power regenerated by the motor generator 11 can be used to charge the vehicle battery 13. Therefore, in step S24, the power supply control unit 33 controls the vehicle battery 13 to input the inputtable power of the vehicle battery 13 out of the power regenerated by the motor generator 11, and to input the power (excess power) obtained by subtracting the inputtable power of the vehicle battery 13 from the regenerated power to the trailer battery 22. In this way, the vehicle system 1 charges the vehicle battery 13 and the trailer battery 22 simultaneously.

[0042] In step S25, the power supply control unit 33 detects the current value and current flow time of the current input / output to / from the vehicle battery 13 and the trailer battery 22. Here, the current value and current flow time of the current passing through the circuit unit 15 are detected by adding up the current values ​​of the current input / output to / from the vehicle battery 13 and the trailer battery 22.

[0043] In step S26, the power supply control unit 33 refers to the smoke generation characteristics of the circuit unit 15 and performs a fire or smoke generation determination to determine whether the circuit unit 15 is at risk of catching fire or generating smoke.

[0044] Fig. 8 is a graph showing smoke generation characteristics. In Fig. 8, the vertical axis represents the smoke generation start time (s) and the horizontal axis represents the current flow (A). As shown in Fig. 8, the smoke generation characteristics specify the smoke generation start time relative to the current flow for each ambient temperature. The smoke generation characteristics show that the larger the current flow, the higher the possibility of smoke generation in a short period of time. It also shows that the higher the ambient temperature, the higher the possibility of smoke generation in a short period of time.

[0045] In the vehicle 2, a smoke generation characteristics map showing the smoke generation characteristics of the circuit unit 15 is stored in advance in a storage unit. The power supply control unit 33 uses the detection result of step S25 to calculate, for example, the current current value, the average current value for the past 1 second, the average current value for the past 10 seconds, and the average current value for the past 100 seconds. Then, the power supply control unit 33 makes a fire or smoke generation determination by referring to the smoke generation characteristics map based on the calculated current values ​​or their average values ​​for different periods.

[0046] In step S27, the power supply control unit 33 determines whether there is a possibility of fire or smoke generation in the circuit unit 15. If there is no possibility of fire or smoke generation in the circuit unit 15 (No in step S27), the process ends.

[0047] On the other hand, if there is a possibility of fire or smoke generation in the circuit unit 15 (Yes in step S27), the mode setting unit 31 ends the boost mode, sets the mode to normal mode in step S28, and ends the process. As a result, in the vehicle system 1, the state in which power is simultaneously input and output from the vehicle battery 13 and the trailer battery 22 to the motor generator 11 is stopped, and power is input and output from the motor generator 11 only from the vehicle battery 13. Therefore, in the vehicle system 1, the possibility of fire or smoke generation due to a large current flowing through the circuit unit 15 can be reduced, and safety can be maintained or improved.

[0048] In the above-described embodiment, the current current value, the average current value for the past 1 second, the average current value for the past 10 seconds, and the average current value for the past 100 seconds are calculated in the determination of whether fire or smoke is occurring. However, these periods are merely examples, and it is also possible to calculate the average current values ​​for a plurality of different predetermined periods going back from the present.

[0049] 4. Modifications Although the present invention has been described above with reference to exemplary embodiments, the present invention is not limited to the specific examples and may employ various other configurations. For example, in the above-described embodiment, the possibility of fire or smoke generation in the circuit unit 15 is determined by referring to the smoke generation characteristics based on the current value (load) of the current flowing through the circuit unit 15 and the duration of current flow. However, the present invention is not limited to this as long as the power supply control unit 33 can determine the possibility of fire or smoke generation in the circuit unit 15 based on the load of the circuit unit 15. For example, the power supply control unit 33 may determine the possibility of fire or smoke generation by directly measuring the temperature (load) of the circuit unit 15. Alternatively, the power supply control unit 33 may calculate the heat generation (load) of the circuit unit 15 based on the current value and resistance of the current flowing through the circuit unit 15 and determine the possibility of fire or smoke generation based on the calculated heat generation.

[0050] In addition, in the above embodiment, if there is a risk of smoke being generated in the circuit section 15 in boost mode, the input and output of power to the trailer battery 22 is restricted, but it is also possible to restrict the input and output of power to either the vehicle battery 13 or the trailer battery 22.

[0051] 5. Summary of the Embodiment As described above, the vehicle 2 of the embodiment includes the vehicle battery 13, the motor generator 11 capable of inputting and outputting power to and from the vehicle battery 13 and an external battery (trailer battery 22), the circuit unit 15 connecting the vehicle battery 13, the external battery, and the motor generator 11, and the control unit 14 controlling the vehicle battery 13 and the external battery. When power is input or output from both the vehicle battery 13 and the external battery, the control unit 14 limits the input or output of power to one of the vehicle battery 13 and the external battery based on the load on the circuit unit 15. This allows the vehicle 2 to drive the motor generator 11 using power simultaneously output from both the vehicle battery 13 and the trailer battery 22, thereby improving driving performance. Furthermore, even when a high load is applied to the circuit unit 15, the vehicle 2 can reduce the risk of fire or smoke from the circuit unit 15 by limiting the input or output of power to one of the vehicle battery 13 and the trailer battery 22. Thus, the vehicle 2 can maintain safety while improving power performance.

[0052] The control unit 14 stops the output from the external battery (trailer battery 22) when the power that can be output from the vehicle battery 13 (outputtable power) is equal to or greater than the power (driving power) used by the motor generator 11. This allows the vehicle 2 to use the vehicle battery 13 with priority.

[0053] The control unit 14 stops the supply of power to the external battery (trailer battery 22) when the power that can be input to the vehicle battery 13 (inputable power) is equal to or greater than the regenerative power of the motor generator 11. This allows the vehicle battery 13 to be charged with priority.

[0054] The control unit 14 refers to the smoke generation characteristics map based on the current value of the high-voltage circuit and the duration of current flow through the high-voltage circuit, and determines whether to limit the input / output of power to either the vehicle battery 13 or the external battery (trailer battery 22). This makes it possible to limit the input / output of power to either the vehicle battery 13 or the trailer battery 22 before the circuit unit 15 catches fire or emits smoke, thereby maintaining safety.

[0055] The control unit 14 limits the input and output of power to the external battery by referring to the smoke generation characteristics map based on the current current value and the average current value over multiple predetermined periods going back from the present. This makes it possible to accurately detect the possibility of smoke generation from the circuit unit 15 even if the current value passing through the circuit unit 15 changes.

[0056] REFERENCE SIGNS LIST 1 vehicle system 2 vehicle 3 trailer 11 motor generator 13 vehicle battery 14 control unit 22 trailer battery 31 mode setting unit 32 state detection unit 33 power supply control unit

Claims

1. A vehicle battery, a motor generator capable of inputting and outputting power to and from the vehicle battery and an external battery provided outside, a circuit unit connecting the vehicle battery, the external battery, and the motor generator, a control unit configured to control the vehicle battery and the external battery based on either a first mode or a second mode, wherein, in the first mode, power is transferred between the motor generator and the vehicle battery, power is transferred between the vehicle battery and the external battery, and no power transfer occurs between the motor generator and the external battery; in the second mode, power is transferred between the motor generator and the vehicle battery, and power is transferred between the motor generator and the external battery; the control unit is configured to shift to the first mode when the load on the circuit unit exceeds a predetermined load in the second mode a vehicle.

2. The power transfer between the vehicle battery and the external battery in the first mode is charging from the external battery to the vehicle battery The vehicle according to claim 1.

3. The control unit, when the power that can be output from the vehicle battery is equal to or greater than the power used by the motor generator, stops the output from the external battery The vehicle according to claim 1.

4. The control unit, when the power that can be input to the vehicle battery is equal to or greater than the regenerative power of the motor generator, stops the power supply to the external battery The vehicle according to claim 1.

5. The control unit, based on the current value of the circuit unit and the energization time of the circuit unit, refers to a smoke generation characteristic map to determine whether to limit the power input and output to one of the vehicle battery and the external battery The vehicle according to any one of claims 1 to 4.

6. The control unit, based on the current value at present and the average value of the current values for a plurality of different predetermined periods traced back from the present, refers to a smoke generation characteristic map to determine whether to limit the power input and output to one of the vehicle battery and the external battery The vehicle according to claim 5.