Vehicle control device

Abstract

To achieve continuous motor drive of front and rear wheels.SOLUTION: An vehicle control device which is mounted on a vehicle comprises: a front wheel drive system which is provided with a first travel motor mechanically connected to front wheels and a first electric power storage body electrically connected to the first travel motor; a rear wheel drive system which is provided with a second travel motor mechanically connected to rear wheels and a second electric power storage body electrically connected to the second travel motor; and a control system which is provided with a processor and a memory connected to each other for mutual communication and controls the first travel motor and the second travel motor. The control system adjusts a torque distribution ratio between the first travel motor and the second travel motor away from a reference distribution ratio when a difference between an SOC of the first electric power storage body and an SOC of the second electric power storage body exceeds a threshold.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a vehicle control device provided in a vehicle. [Background technology]

[0002] Vehicles equipped with electric motors for driving the front and rear wheels have been developed as electric vehicles and hybrid vehicles (see Patent Documents 1 to 3). By providing electric motors for the front and rear wheels in this way, the torque distribution ratio between the front and rear wheels can be freely controlled, and the running performance of the vehicle can be improved. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-68680 A [Patent Document 2] JP 2018-50388 A [Patent Document 3] International Publication No. 2020 / 184537 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, it has been considered to connect a battery for the front wheels to the electric motor for the front wheels, and a battery for the rear wheels to the electric motor for the rear wheels. In this way, when the batteries for the front wheels and the rear wheels are separately mounted, it may be difficult to continue the motor drive of the front wheels and the rear wheels. In other words, when the power of the battery for the front wheels or the rear wheels runs out first, it is difficult to continue the motor drive by the battery that has run out. Since stopping the motor drive of the front wheels or the rear wheels is a factor that reduces the running performance of the vehicle, it is required to continue the motor drive of the front wheels and the rear wheels.

[0005] The object of the present invention is to continue to motorize the front and rear wheels. [Means for solving the problem]

[0006] A vehicle control device of one embodiment is a vehicle control device provided in a vehicle, and includes a front-wheel drive system including a first traction motor mechanically connected to front wheels and a first power storage body electrically connected to the first traction motor, a rear-wheel drive system including a second traction motor mechanically connected to rear wheels and a second power storage body electrically connected to the second traction motor, and a control system including a processor and a memory communicatively connected to each other, and controlling the first traction motor and the second traction motor, wherein the control system changes the torque distribution ratio between the first traction motor and the second traction motor from a reference distribution ratio when a difference between the SOC of the first power storage body and the SOC of the second power storage body exceeds a threshold value. Effect of the Invention

[0007] According to one aspect of the present invention, when the difference between the SOC of the first power storage body and the SOC of the second power storage body exceeds a threshold value, the control system changes the torque distribution ratio between the first traction motor and the second traction motor from the reference distribution ratio, thereby allowing the motor drive of the front wheels and the rear wheels to continue. [Brief description of the drawings]

[0008] [Figure 1] 1 is a diagram showing an example of the configuration of a vehicle provided with a vehicle control device according to an embodiment of the present invention; [Diagram 2] FIG. 1 is a diagram illustrating an example of a vehicle control device. [Diagram 3] FIG. 2 is a diagram illustrating an example of a basic structure of each control unit. [Figure 4] 10 is a flowchart showing an example of a procedure for executing passive control. [Diagram 5] 10 is a flowchart showing an example of a procedure for executing passive control. [Figure 6]FIG. 11 is a diagram illustrating an example of timing at which passive control is executed. [Figure 7] FIG. 4 is a diagram showing an example of a powering torque distribution ratio and a regenerative torque distribution ratio changed in passive control. [Figure 8] FIG. 4 is a diagram showing an example of changes in SOCf and SOCr before and after the execution of passive control. [Figure 9] FIG. 4 is a diagram showing an example of deterioration characteristics of a battery module. [Figure 10] 4 is a flowchart showing an example of an execution procedure of condition determination control 1. [Figure 11] FIG. 2 is a diagram showing an example of an execution status of the condition determination control 1. [Figure 12] 10 is a flowchart showing an example of an execution procedure of condition determination control 2. [Figure 13] 10 is a flowchart showing an example of an execution procedure of condition determination control 2. [Figure 14] FIG. 11 is a diagram showing an example of an execution status of condition determination control 2. [Figure 15] FIG. 11 is a diagram showing an example of an execution status of condition determination control 2. [Figure 16] 4 is a flowchart showing an example of an execution procedure of active control. [Figure 17] 4 is a flowchart showing an example of an execution procedure of active control. [Figure 18] 11A and 11B are diagrams illustrating an example of changes in the integrated charge amount and the integrated discharge amount before and after the execution of active control. [Figure 19] FIG. 4 is a diagram showing an example of a correction coefficient for correcting a charging current or a discharging current. [Figure 20] FIG. 4 is a diagram showing an example of an accumulation state of a charging current and an accumulation state of a discharging current. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, the same or substantially same configurations and elements will be designated by the same reference numerals and will not be described repeatedly.

[0010] [vehicle] FIG. 1 is a diagram showing an example of the configuration of a vehicle 11 provided with a vehicle control device 10 according to an embodiment of the present invention. As shown in FIG. 1, the vehicle 11 is provided with a front axle 21 for driving the front wheels 20, and a rear axle 41 for driving the rear wheels 40. The front axle 21, in which an electric motor is incorporated, is connected to a front battery pack 23 via a front inverter 22. The front axle 21, the front inverter 22, and the front battery pack 23 constitute a front-wheel drive system 30 for driving the front wheels 20. Similarly, the rear axle 41, in which an electric motor is incorporated, is connected to a rear battery pack 43 via a rear inverter 42. The rear axle 41, the rear inverter 42, and the rear battery pack 43 constitute a rear-wheel drive system 50 for driving the rear wheels 40.

[0011] [Front-wheel drive system] Fig. 2 is a diagram showing an example of the vehicle control device 10. As shown in Fig. 2, a front motor (first driving motor) 31 and a front differential 32 are provided on the front axle 21 of the front wheel drive system 30. The front differential 32 is connected to a rotor 31r of the front motor 31 via a gear train 33. An axle 34 extends from the front differential 32, and the front wheels 20 are connected to the axle 34. In this way, the front wheels 20 are mechanically connected to the front motor 31 of the front wheel drive system 30.

[0012] Further, a front inverter 22 is connected to a stator 31s of the front motor 31, and a front battery pack 23 is connected to the front inverter 22. The front battery pack 23 is provided with a battery module (first power storage body) 35 consisting of a plurality of battery cells. In this manner, the front motor 31, which is an electric motor, is electrically connected to the battery module 35 of the front wheel drive system 30. The battery module 35 shown in the figure is a lithium ion battery.

[0013] The front battery pack 23 is provided with a front battery control unit 36 ​​that monitors the charging and discharging of the battery module 35, and a battery sensor 37 that detects the charging and discharging current, terminal voltage, etc. The front battery control unit 36 ​​calculates the SOC (State of Charge) that is the charging state of the battery module 35 based on the charging and discharging current, terminal voltage, etc. detected by the battery sensor 37. The SOC of the battery module 35 is a ratio that indicates the remaining amount of electricity stored in the battery module 35, and is the ratio of the amount of stored electricity to the full charge capacity of the battery module 35. In the following description, the SOC of the battery module 35 provided in the front battery pack 23 is referred to as "SOCf."

[0014] The front battery control unit 36 ​​calculates the integrated charge amount Icf and the integrated discharge amount Idf of the battery module 35 based on the charge and discharge current detected by the battery sensor 37. That is, the front battery control unit 36 ​​calculates the integrated charge amount Icf of the battery module 35 by integrating the charge current of the battery module 35. The front battery control unit 36 ​​also calculates the integrated discharge amount Idf of the battery module 35 by integrating the discharge current of the battery module 35.

[0015] As described later, three charge / discharge ranges R1 to R3 are set for the battery modules 35 and 45, and the front battery control unit 36 ​​calculates an integrated charge amount (first integrated charge amount) Icf and an integrated discharge amount (first integrated discharge amount) Idf for each of the charge / discharge ranges R1 to R3. The integrated charge amount Icf is the charge amount obtained by integrating the charge current from the time of shipment from the factory, that is, the charge amount [Ah] obtained by integrating the charge current from the new battery modules 35 and 45. Similarly, the integrated discharge amount Idf is the discharge amount obtained by integrating the discharge current from the time of shipment from the factory, that is, the discharge amount [Ah] obtained by integrating the discharge current from the new battery modules 35 and 45.

[0016] Further, a front motor control unit 38 is connected to the front inverter 22 in order to control the front motor 31. The front motor control unit 38 controls the front inverter 22, which is made up of a plurality of switching elements and the like, thereby controlling the electrified state of the stator 31s and controlling the motor torque (powering torque, regenerative torque) of the front motor 31. When the front motor 31 is controlled to be in a powering state, power is supplied from the battery module 35 to the front motor 31. On the other hand, when the front motor 31 is controlled to be in a regenerative state, i.e., a power generating state, power is supplied from the front motor 31 to the battery module 35.

[0017] [Rear wheel drive system] 2, a rear motor (second traction motor) 51 and a rear differential 52 are provided on the rear axle 41 of the rear-wheel drive system 50. The rear differential 52 is connected to a rotor 51r of the rear motor 51 via a gear train 53. An axle 54 extends from the rear differential 52, and the rear wheels 40 are connected to the axle 54. In this manner, the rear motor 51 of the rear-wheel drive system 50 is mechanically connected to the rear wheels 40.

[0018] A rear inverter 42 is connected to the stator 51s of the rear motor 51, and a rear battery pack 43 is connected to the rear inverter 42. The rear battery pack 43 is provided with a battery module (second power storage body) 45 consisting of a plurality of battery cells. In this manner, the rear motor 51, which is an electric motor, is electrically connected to the battery module 45 of the rear wheel drive system 50. The battery module 45 shown in the figure is a lithium ion battery.

[0019] The rear battery pack 43 is provided with a rear battery control unit 56 that monitors the charging and discharging of the battery module 45, and a battery sensor 57 that detects the charging and discharging current, terminal voltage, etc. The rear battery control unit 56 calculates the SOC, which is the state of charge of the battery module 45, based on the charging and discharging current, terminal voltage, etc. detected by the battery sensor 57. The SOC of the battery module 45 is a ratio that indicates the remaining amount of electricity stored in the battery module 45, and is the ratio of the amount of stored electricity to the full charge capacity of the battery module 45. In the following description, the SOC of the battery module 45 provided in the rear battery pack 43 is referred to as "SOCr."

[0020] The rear battery control unit 56 calculates the integrated charge amount Icr and the integrated discharge amount Idr of the battery module 45 based on the charge and discharge current detected by the battery sensor 57. That is, the rear battery control unit 56 calculates the integrated charge amount Icr of the battery module 45 by integrating the charge current of the battery module 45. In addition, the rear battery control unit 56 calculates the integrated discharge amount Idr of the battery module 45 by integrating the discharge current of the battery module 45.

[0021] As described later, three charge / discharge ranges R1 to R3 are set for the battery module 45, and the rear battery control unit 56 calculates an integrated charge amount (second integrated charge amount) Icr and an integrated discharge amount (second integrated discharge amount) Idr for each of the charge / discharge ranges R1 to R3. The integrated charge amount Icr is the charge amount obtained by integrating the charge current from the time of shipment from the factory, that is, the charge amount [Ah] obtained by integrating the charge current from the new battery module 45. Similarly, the integrated discharge amount Idr is the discharge amount obtained by integrating the discharge current from the time of shipment from the factory, that is, the discharge amount [Ah] obtained by integrating the discharge current from the new battery module 45.

[0022] A rear motor control unit 58 is connected to the rear inverter 42 to control the rear motor 51. The rear motor control unit 58 controls the rear inverter 42, which is made up of a plurality of switching elements and the like, thereby controlling the electrified state of the stator 51s and controlling the motor torque (powering torque, regenerative torque) of the rear motor 51. When the rear motor 51 is controlled to a powering state, power is supplied from the battery module 45 to the rear motor 51. On the other hand, when the rear motor 51 is controlled to a regenerative state, i.e., a power generating state, power is supplied from the rear motor 51 to the battery module 45.

[0023] An on-board charger 59 is connected to the front battery pack 23 and the rear battery pack 43 for charging the battery modules 35, 45 using an external power source (not shown).

[0024] [Control System] 2, the vehicle control device 10 is provided with a control system 60 consisting of a plurality of electronic control units in order to control the front wheel drive system 30 and the rear wheel drive system 50. The electronic control units constituting the control system 60 include the front battery control unit 36, the front motor control unit 38, the rear battery control unit 56, and the rear motor control unit 58 described above. In addition, the control system 60 is provided with a vehicle control unit 61 that outputs control signals to the control units 36, 38, 56, and 58 described above.

[0025] The control units 36, 38, 56, 58, and 61 constituting the control system 60 are connected to each other so as to be able to communicate with each other via an in-vehicle network 62 such as a CAN. The vehicle control unit 61 sets operation targets for the front motor 31, the rear motor 51, etc. based on input information from the various control units and various sensors described below. Then, the vehicle control unit 61 generates control signals according to the operation targets for the front motor 31, the rear motor 51, etc., and outputs these control signals to the front motor control unit 38 and the rear motor control unit 58.

[0026] Sensors connected to the vehicle control unit 61 include a vehicle speed sensor 63 that detects the vehicle speed, which is the traveling speed of the vehicle 11, an accelerator sensor 64 that detects the operation status of the accelerator pedal, and a brake sensor 65 that detects the operation status of the brake pedal. Also connected to the vehicle control unit 61 is a start switch 66 that is operated by the driver when starting up the control system 60.

[0027] Fig. 3 is a diagram showing an example of the basic structure of each of the control units 36, 38, 56, 58, 61. As shown in Fig. 3, the control unit, which is an electronic control unit, has a microcontroller 72 incorporating a processor 70 and a main memory (memory) 71, etc. A predetermined program is stored in the main memory 71, and the program is executed by the processor 70. The processor 70 and the main memory 71 are connected to each other so as to be able to communicate with each other. Note that a plurality of processors 70 may be incorporated in the microcontroller 72, and a plurality of main memories 71 may be incorporated in the microcontroller 72.

[0028] The control unit is also provided with an input circuit 73, a drive circuit 74, a communication circuit 75, an external memory 76, a power supply circuit 77, and the like. The input circuit 73 converts signals input from various sensors into signals that can be input to the microcontroller 72. The drive circuit 74 generates drive signals for various devices such as the inverters 22 and 42 described above based on signals output from the microcontroller 72. The communication circuit 75 converts signals output from the microcontroller 72 into communication signals directed to other control units. The communication circuit 75 also converts communication signals received from other control units into signals that can be input to the microcontroller 72. The power supply circuit 77 supplies a stable power supply voltage to the microcontroller 72, the input circuit 73, the drive circuit 74, the communication circuit 75, the external memory 76, and the like. The external memory 76, which is a non-volatile memory, stores programs and various data.

[0029] [Passive control] Next, passive control, which is SOC equalization control for bringing the SOCf and SOCr of the battery module 35 closer to each other, will be described. Figs. 4 and 5 are flowcharts showing an example of an execution procedure of passive control. The flowcharts shown in Figs. 4 and 5 are connected to each other at the points indicated by the symbols A, B, and C. Each step of the passive control shown in Figs. 4 and 5 shows a process executed by the processor 70 constituting the control system 60. Furthermore, the passive control shown in Figs. 4 and 5 is a control executed by the control system 60 at a predetermined cycle after the control system 60 is started.

[0030] 4, in step S10, the SOCf of the battery module 35 and the SOCr of the battery module 45 are read. In the following step S11, the SOCr is subtracted from the SOCf to calculate ΔSOC, which is the SOC difference. Then, in step S12, it is determined whether the absolute value of ΔSOC exceeds a predetermined start threshold (threshold) α. In step S12, if it is determined that the absolute value of ΔSOC exceeds the start threshold α, that is, if it is determined that the SOCf and SOCr are deviated from each other, the process proceeds to step S13, where a passive control flag Fp1, which means that passive control is executed, is set (Fp1=1).

[0031] In the next step S14, it is determined whether or not SOCf exceeds SOCr. If it is determined in step S14 that SOCf exceeds SOCr, the SOCf of the front battery module 35 is excessively high, so the process proceeds to step S15, where the torque distribution ratio of the front motor 31 and the rear motor 51 is changed from a predetermined reference distribution ratio. In other words, the torque distribution ratio of the front motor 31 and the rear motor 51 is changed from the reference distribution ratio so as to promote discharging of the front battery module 35 to lower the SOCf, and promote charging of the rear battery module 45 to raise the SOCr.

[0032] Here, the reference distribution ratio is a torque distribution ratio between the front motor 31 and the rear motor 51 that is set in advance for each vehicle model. For example, when the front / rear reference distribution ratio is set to "50:50", when the target motor torque is set from the required driving force based on the accelerator operation, etc., the motor torques of the front motor 31 and the rear motor 51 are controlled to be the same value. Also, for example, when the front / rear reference distribution ratio is set to "40:60" with a rear-wheel bias, when the target motor torque is set from the required driving force based on the accelerator operation, etc., the motor torque of the rear motor 51 is controlled to be 20% larger than that of the front motor 31. Also, for example, when the front / rear reference distribution ratio is set to "60:40" with a front-wheel bias, when the target motor torque is set from the required driving force based on the accelerator operation, etc., the motor torque of the front motor 31 is controlled to be 20% larger than that of the rear motor 51. Note that the reference distribution ratio may be a fixed torque distribution ratio or may be a torque distribution ratio that changes depending on the driving situation. Furthermore, the reference distribution ratio for the powering torque and the reference distribution ratio for the regenerative torque may be the same distribution ratio or may be different distribution ratios.

[0033] In step S15, the torque distribution ratio of the front motor 31 and the rear motor 51 is changed from the reference distribution ratio so as to promote discharge of the front-side battery module 35 and reduce the SOCf. That is, the powering torque distribution ratio is changed to be biased toward the front wheels, so that the powering torque allocated to the front motor 31 is increased from the powering torque allocated based on the reference distribution ratio, while the powering torque allocated to the rear motor 51 is decreased from the powering torque allocated based on the reference distribution ratio. This promotes discharge of the front-side battery module 35 to promote a decrease in SOCf, and suppresses discharge of the rear-side battery module 45 to suppress a decrease in SOCr. That is, the powering states of the front motor 31 and the rear motor 51 during acceleration running and steady running are controlled so that the SOCf and SOCr approach each other. The powering torque allocated to the front motor 31 is a target value of the powering torque allocated to the front motor 31, that is, a target powering torque allocated to the front motor 31. Similarly, the allocated power running torque of the rear motor 51 is a target value of the power running torque allocated to the rear motor 51 , that is, a target power running torque allocated to the rear motor 51 .

[0034] In step S15, the torque distribution ratio of the front motor 31 and the rear motor 51 is changed from the reference distribution ratio so as to encourage charging of the rear battery module 45 and increase the SOCr. That is, the regenerative torque distribution ratio is changed to favor the rear wheels, so that the allocated regenerative torque of the front motor 31 is reduced from the allocated regenerative torque based on the reference distribution ratio, while the allocated regenerative torque of the rear motor 51 is increased from the allocated regenerative torque based on the reference distribution ratio. This makes it possible to suppress the charging of the front battery module 35 and suppress an increase in SOCf, and to encourage charging of the rear battery module 45 and promote an increase in SOCr. That is, the regenerative states of the front motor 31 and the rear motor 51 during deceleration driving are controlled so that the SOCf and SOCr approach each other. The allocated regenerative torque of the front motor 31 is a target value of the regenerative torque allocated to the front motor 31, that is, a target regenerative torque allocated to the front motor 31. Similarly, the allocated regenerative torque of the rear motor 51 is a target value of the regenerative torque allocated to the rear motor 51 , that is, a target regenerative torque allocated to the rear motor 51 .

[0035] On the other hand, if it is determined in step S14 that the SOCf falls below the SOCr, the SOCr of the rear battery module 45 is excessively high, so the process proceeds to step S16, where the torque distribution ratio of the front motor 31 and the rear motor 51 is changed from a predetermined reference distribution ratio. In other words, the torque distribution ratio of the front motor 31 and the rear motor 51 is changed from the reference distribution ratio so as to encourage charging of the front battery module 35 to increase the SOCf, and to encourage discharging of the rear battery module 45 to decrease the SOCr.

[0036] In step S16, the torque distribution ratio of the front motor 31 and the rear motor 51 is changed from the reference distribution ratio so as to promote discharge of the rear-side battery module 45 and reduce the SOCr. That is, the powering torque distribution ratio is changed to be rear-wheel biased, so that the powering torque allocated to the front motor 31 is reduced from the powering torque allocated based on the reference distribution ratio, while the powering torque allocated to the rear motor 51 is increased from the powering torque allocated based on the reference distribution ratio. This makes it possible to suppress discharge of the front-side battery module 35 and suppress a decrease in SOCf, and promote discharge of the rear-side battery module 45 to promote a decrease in SOCr. That is, the powering states of the front motor 31 and the rear motor 51 during acceleration driving and steady driving are controlled so that SOCf and SOCr approach each other.

[0037] In step S16, the torque distribution ratio of the front motor 31 and the rear motor 51 is changed from the reference distribution ratio so as to promote charging of the front battery module 35 and increase the SOCf. That is, the regenerative torque distribution ratio is changed to favor the front wheels, so that the allocated regenerative torque of the front motor 31 is increased from the allocated regenerative torque based on the reference distribution ratio, while the allocated regenerative torque of the rear motor 51 is decreased from the allocated regenerative torque based on the reference distribution ratio. This promotes charging of the front battery module 35 to promote an increase in SOCf, and suppresses charging of the rear battery module 45 to suppress an increase in SOCr. That is, the regenerative states of the front motor 31 and the rear motor 51 during deceleration driving are controlled so that SOCf and SOCr approach each other.

[0038] 5, in step S17, SOCf and SOCr are read, and in step S18, ΔSOC is calculated by subtracting SOCr from SOCf. In the following step S19, it is determined whether the absolute value of ΔSOC is below an end threshold γ that is smaller than a start threshold α. In step S19, if it is determined that the absolute value of ΔSOC is below the end threshold γ, that is, if it is determined that ΔSOC has been eliminated, the process proceeds to step S20, where the torque distribution ratio of the powering torque and the regenerative torque is returned to the reference distribution ratio, and the process proceeds to step S21, where the passive control flag Fp1 is reset (Fp1=0).

[0039] Here, Fig. 6 is a diagram showing an example of the timing at which passive control is executed. Fig. 7 is a diagram showing an example of the powering torque distribution ratio and the regenerative torque distribution ratio changed in passive control. Fig. 8 is a diagram showing an example of changes in SOCf and SOCr before and after the execution of passive control. In Fig. 7, "Taf, Tafx" are the allocated powering torque of the front motor 31, "Tar, Tarx" are the allocated powering torque of the rear motor 51, "Tbf, Tbfx" are the allocated regenerative torque of the front motor 31, and "Tbr, Tbrx" are the allocated regenerative torque of the rear motor 51.

[0040] As shown at time t1 in Fig. 6, when ΔSOC, which is the difference between SOCf and SOCr, exceeds the start threshold value α (symbol a1), the passive control flag Fp1 is set and the passive control is started (symbol b1). Then, the torque distribution ratio is changed from the reference distribution ratio to gradually reduce ΔSOC, and as shown at time t2, when ΔSOC falls below the end threshold value γ (symbol a2), the passive control flag Fp1 is released and the passive control is ended (symbol b2). In other words, the torque distribution ratio that was changed by the passive control is returned to the reference distribution ratio.

[0041] 7, when SOCf exceeds SOCr under passive control, the allocated powering torque Taf of the front motor 31 is increased (arrow x1f) above the allocated powering torque Tafx based on the reference distribution ratio, and the allocated powering torque Tar of the rear motor 51 is decreased (arrow x1r) below the allocated powering torque Tarx based on the reference distribution ratio. This promotes discharge of the front battery module 35 to promote a decrease in SOCf, and suppresses discharge of the rear battery module 45 to suppress a decrease in SOCr, so that SOCf and SOCr can be brought closer to each other as shown in FIG.

[0042] On the other hand, as shown by arrows x2f and x2r in Fig. 7, when SOCf falls below SOCr under passive control, the allocated powering torque Taf of the front motor 31 is reduced below the allocated powering torque Tafx based on the reference distribution ratio (arrow x2f), and the allocated powering torque Tar of the rear motor 51 is increased above the allocated powering torque Tarx based on the reference distribution ratio (arrow x2r). This makes it possible to suppress the discharge of the front battery module 35 and suppress the decrease in SOCf, and to promote the discharge of the rear battery module 45 and promote the decrease in SOCr, so that SOCf and SOCr can be brought closer to each other as shown in Fig. 8.

[0043] 7, when SOCf exceeds SOCr under passive control, the allocated regenerative torque Tbf of the front motor 31 is reduced below the allocated regenerative torque Tbfx based on the reference distribution ratio (arrow x3f), and the allocated regenerative torque Tbr of the rear motor 51 is increased above the allocated regenerative torque Tbrx based on the reference distribution ratio (arrow x3r). This makes it possible to suppress charging of the front battery module 35 and suppress an increase in SOCf, and to promote charging of the rear battery module 45 and promote an increase in SOCr, so that SOCf and SOCr can be brought closer to each other as shown in FIG.

[0044] On the other hand, as shown by arrows x4f and x4r in Fig. 7, when SOCf falls below SOCr under passive control, the allocated regenerative torque Tbf of the front motor 31 is increased (arrow x4f) above the allocated regenerative torque Tbfx based on the reference distribution ratio, and the allocated regenerative torque Tbr of the rear motor 51 is decreased (arrow x4r) below the allocated regenerative torque Tbrx based on the reference distribution ratio. This promotes charging of the front battery module 35 to promote an increase in SOCf, and suppresses charging of the rear battery module 45 to suppress an increase in SOCr, so that SOCf and SOCr can be brought closer to each other as shown in Fig. 8.

[0045] As described above, by executing the passive control, the SOCf of the front battery module 35 and the SOCr of the rear battery module 45 can be brought closer to each other. This allows the SOCf and SOCr to be reduced almost equally while the vehicle 11 is running, and allows the motor drive of the front wheels 20 and the rear wheels 40 to be continued for a long period of time. In other words, the motor drive of the front wheels 20 and the rear wheels 40 can be continued for a long period of time without excessively decreasing only one of the SOCf and SOCr.

[0046] [Battery module deterioration characteristics] As described above, the illustrated battery modules 35 and 45 are lithium ion batteries that transfer lithium ions between positive and negative electrodes during charging and discharging. The battery modules 35 and 45 use a lithium-containing oxide as a positive electrode active material, and graphite or silicon having a layered structure as a negative electrode active material.

[0047] FIG. 9 is a diagram showing an example of the deterioration characteristic of the battery module 35, 45. FIG. 9 shows the dV / dQ curve of the battery module 35, 45. The dV / dQ curve is a curve obtained by differentiating the voltage V in the discharge curve of the battery module 35, 45 by the capacity Q. As shown in FIG. 9, the capacity at which the layer structure in the negative electrode active material changes significantly due to expansion and contraction during charging and discharging can be detected as peaks P1, P2 of the dV / dQ curve. In other words, charging and discharging at and near the peaks P1, P2 were factors that deteriorated the battery module 35, 45 compared to charging and discharging in other regions. In this way, the battery module 35, 45 has different deterioration characteristics for each capacity at which charging and discharging are performed.

[0048] As shown in FIG. 9, four boundary values ​​S1 to S4 related to capacity are set for the battery modules 35 and 45. Three charge / discharge ranges (charge / discharge ranges) R1 to R3 are set for the battery modules 35 and 45 between a boundary value (upper SOC) S1 and a boundary value (lower SOC) S4. That is, a charge / discharge range R1 defined by boundary values ​​S1 and S2, a charge / discharge range R2 defined by boundary values ​​S2 and S3, and a charge / discharge range R3 defined by boundary values ​​S3 and S4 are set for the battery modules 35 and 45. The boundary value S1 is the capacity when the SOC is calculated as 100%, that is, the upper limit capacity when the battery modules 35 and 45 are charged. The boundary value S4 is the capacity when the SOC is calculated as 0%, that is, the lower limit capacity when the battery modules 35 and 45 are discharged.

[0049] As shown in FIG. 9, the charge / discharge range R1 includes a peak P1 of the dV / dQ curve, and the charge / discharge range R3 includes a peak P2 of the dV / dQ curve. That is, even if the charge / discharge amount is the same, charge / discharge in the charge / discharge ranges R1 and R3 is a factor that deteriorates the battery modules 35 and 45 compared to charge / discharge in the charge / discharge range R2. In this way, the battery modules 35 and 45 have different deterioration characteristics for each of the charge / discharge ranges R1 to R3. Therefore, the control system 60 executes active control that deteriorates each battery module 35 and 45 almost equally by controlling the charge / discharge amount for each of the charge / discharge ranges R1 to R3.

[0050] [Condition judgment control 1 (active control)] Hereinafter, condition determination controls 1 and 2 for determining the execution conditions of active control will be described, followed by a description of active control, which is a degradation equalization control for causing the battery modules 35 and 45 to deteriorate almost evenly. FIG. 10 is a flowchart showing an example of an execution procedure of the condition determination control 1. FIG. 11 is a diagram showing an example of an execution status of the condition determination control 1. Note that each step of the condition determination control 1 shown in FIG. 10 shows a process executed by the processor 70 constituting the control system 60. Moreover, the condition determination control 1 shown in FIG. 10 is a control executed by the control system 60 at predetermined intervals after the control system 60 is started up.

[0051] 10, in step S30, the SOCf and SOCr of the battery modules 35, 45 are read. In step S31, the current charge / discharge range R1-R3 of the battery module 35 is determined based on the SOCf of the front battery module 35. In addition, in step S32, the current charge / discharge range R1-R3 of the battery module 45 is determined based on the SOCr of the rear battery module 45.

[0052] In step S32, it is determined whether the charge / discharge ranges R1 to R3 of the battery module 35 and the battery module 45 are the same. That is, it is determined whether the SOCf and SOCr of the battery modules 35, 45 are within the same charge / discharge range (same range). If it is determined in step S33 that the charge / discharge ranges are the same, the process proceeds to step S34, where a first determination flag Fa1 is set (Fa1=1). On the other hand, if it is determined in step S33 that the charge / discharge ranges are not the same, the process proceeds to step S35, where the first determination flag Fa1 is cleared (Fa1=0).

[0053] 11, when the SOCr decreases and the charge / discharge range R1 changes to the charge / discharge range R2 (symbol a1) while the SOCf is within the charge / discharge range R1, the first determination flag Fa1 is cleared (symbol b1) because the charge / discharge ranges R1 and R2 are different. Also, when the SOCf decreases and the charge / discharge range R1 changes to the charge / discharge range R2 (symbol a2) while the SOCr is within the charge / discharge range R2, the first determination flag Fa1 is set (symbol b2) because the charge / discharge ranges R2 and R3 match. Also, when the SOCf decreases and the charge / discharge range R2 changes to the charge / discharge range R3 (symbol a3) while the SOCr is within the charge / discharge range R2, the first determination flag Fa1 is cleared (symbol b3) because the charge / discharge ranges R2 and R3 are different. Furthermore, as shown at time t6, when SOCf is fluctuating within the charge / discharge range R3 and SOCr decreases and shifts from the charge / discharge range R2 to the charge / discharge range R3 (symbol a4), the first judgment flag Fa1 is set (symbol b4) because the charge / discharge range R3 matches.

[0054] 10, in step S36, SOCr is subtracted from SOCf to calculate ΔSOC, which is the SOC difference. Next, in step S37, it is determined whether the absolute value of ΔSOC is below a predetermined start threshold value β. If it is determined in step S37 that the absolute value of ΔSOC is below the start threshold value β, that is, if SOCf and SOCr are close to each other, the process proceeds to step S38, where a second determination flag Fa2 is set (Fa2=1). On the other hand, if it is determined in step S37 that the absolute value of ΔSOC is equal to or greater than the start threshold value β, that is, if SOCf and SOCr are far from each other, the process proceeds to step S39, where the second determination flag Fa2 is cleared (Fa2=0).

[0055] 11, when the absolute value of ΔSOC becomes equal to or greater than the start threshold value β (symbol c1), the second determination flag Fa2 is cleared (symbol d1).In addition, when the absolute value of ΔSOC becomes smaller than the start threshold value β (symbol c2), the second determination flag Fa2 is set (symbol d2) as shown at time t3.

[0056] [Condition judgment control 2 (active control)] Next, the condition determination control 2 for determining the execution condition of the active control will be described. Fig. 12 and Fig. 13 are flowcharts showing an example of the execution procedure of the condition determination control 2, and Fig. 14 and Fig. 15 are diagrams showing an example of the execution status of the condition determination control 2. The flowcharts shown in Fig. 12 and Fig. 13 are connected to each other at the point of reference D. Furthermore, each step of the condition determination control 2 shown in Fig. 12 and Fig. 13 shows a process executed by the processor 70 constituting the control system 60. Furthermore, the condition determination control 2 shown in Fig. 12 and Fig. 13 is a control executed by the control system 60 at a predetermined cycle after the control system 60 is started.

[0057] As described above, the front battery control unit 36 ​​calculates the integrated charge amount Icf and the integrated discharge amount Idf for each of the charge / discharge ranges R1 to R3. In the following description, the integrated charge amount Icf in the charge / discharge range R1 is referred to as "Icf1", the integrated charge amount Icf in the charge / discharge range R2 is referred to as "Icf2", and the integrated charge amount Icf in the charge / discharge range R3 is referred to as "Icf3". In addition, the integrated discharge amount Idf in the charge / discharge range R1 is referred to as "Idf1", the integrated discharge amount Idf in the charge / discharge range R2 is referred to as "Idf2", and the integrated discharge amount Idf in the charge / discharge range R3 is referred to as "Idf3".

[0058] As described above, the rear battery control unit 56 calculates the integrated charge amount Icr and the integrated discharge amount Idr for each of the charge / discharge ranges R1 to R3. In the following description, the integrated charge amount Icr in the charge / discharge range R1 is referred to as "Icr1," the integrated charge amount Icr in the charge / discharge range R2 is referred to as "Icr2," and the integrated charge amount Icr in the charge / discharge range R3 is referred to as "Icr3." In addition, the integrated discharge amount Idr in the charge / discharge range R1 is referred to as "Idr1," the integrated discharge amount Idr in the charge / discharge range R2 is referred to as "Idr2," and the integrated discharge amount Idr in the charge / discharge range R3 is referred to as "Idr3."

[0059] 12, in step S40, the integrated charge amounts Icf1, Icf2, and Icf3 of the battery module 35 are read, and the integrated charge amounts Icr1, Icr2, and Icr3 of the battery module 45 are read. In the following step S41, the integrated discharge amounts Idf1, Idf2, and Idf3 of the battery module 35 are read, and the integrated discharge amounts Idr1, Idr2, and Idr3 of the battery module 45 are read.

[0060] In step S42, the integrated charge amount Icr1 is subtracted from the integrated charge amount Icf1 to calculate the integrated charge amount difference ΔIc1 in the charge / discharge range R1. In the following step S43, it is determined whether the absolute value of the difference ΔIc1 exceeds a predetermined charge amount threshold Xc1. If it is determined in step S43 that the absolute value of the difference ΔIc1 exceeds the charge amount threshold Xc1, the integrated charge amount in the charge / discharge range R1 has deviated, so the process proceeds to step S44, where the charge difference flag Fa31 is set (Fa31=1). On the other hand, if it is determined in step S43 that the absolute value of the difference ΔIc1 is equal to or less than the charge amount threshold Xc1, the integrated charge amount in the charge / discharge range R1 has not deviated, so the process proceeds to step S45, where the charge difference flag Fa31 is cleared (Fa31=0).

[0061] In step S46, the integrated charge amount Icr2 is subtracted from the integrated charge amount Icf2 to calculate the integrated charge amount difference ΔIc2 in the charge / discharge range R2. In the following step S47, it is determined whether the absolute value of the difference ΔIc2 exceeds a predetermined charge amount threshold Xc2. If it is determined in step S47 that the absolute value of the difference ΔIc2 exceeds the charge amount threshold Xc2, the integrated charge amount in the charge / discharge range R2 has deviated, so the process proceeds to step S48, where the charge difference flag Fa32 is set (Fa32=1). On the other hand, if it is determined in step S47 that the absolute value of the difference ΔIc2 is equal to or less than the charge amount threshold Xc2, the integrated charge amount in the charge / discharge range R2 has not deviated, so the process proceeds to step S49, where the charge difference flag Fa32 is cleared (Fa32=0).

[0062] In step S50, the integrated charge amount Icr3 is subtracted from the integrated charge amount Icf3 to calculate the integrated charge amount difference ΔIc3 in the charge / discharge range R3. In the following step S51, it is determined whether the absolute value of the difference ΔIc3 exceeds a predetermined charge amount threshold Xc3. If it is determined in step S51 that the absolute value of the difference ΔIc3 exceeds the charge amount threshold Xc3, the integrated charge amount in the charge / discharge range R3 has deviated, so the process proceeds to step S52, where the charge difference flag Fa33 is set (Fa33=1). On the other hand, if it is determined in step S51 that the absolute value of the difference ΔIc3 is equal to or less than the charge amount threshold Xc3, the integrated charge amount in the charge / discharge range R3 has not deviated, so the process proceeds to step S53, where the charge difference flag Fa33 is cleared (Fa33=0).

[0063] That is, as shown at time t1 in Fig. 14, when the absolute value of the difference ΔIc1 in the integrated charge amount in the charge / discharge range R1 exceeds a predetermined charge amount threshold Xc1 (symbol a1), the charge difference flag Fa31 is set (symbol b1). Also, as shown at time t2, when the absolute value of the difference ΔIc2 in the integrated charge amount in the charge / discharge range R2 exceeds a predetermined charge amount threshold Xc2 (symbol c1), the charge difference flag Fa32 is set (symbol d1). Also, as shown at time t3, when the absolute value of the difference ΔIc3 in the integrated charge amount in the charge / discharge range R3 exceeds a predetermined charge amount threshold Xc3 (symbol e1), the charge difference flag Fa33 is set (symbol f1).

[0064] As shown in the flowchart of FIG. 13, in step S54, the integrated discharge amount Idr1 is subtracted from the integrated discharge amount Idf1 to calculate the difference ΔId1 of the integrated discharge amount in the charge / discharge range R1. In the following step S55, it is determined whether the absolute value of the difference ΔId1 exceeds a predetermined discharge amount threshold Xd1. If it is determined in step S55 that the absolute value of the difference ΔId1 exceeds the discharge amount threshold Xd1, the integrated discharge amount in the charge / discharge range R1 has deviated, so the process proceeds to step S56, where the discharge difference flag Fa41 is set (Fa41=1). On the other hand, if it is determined in step S55 that the absolute value of the difference ΔId1 is equal to or less than the discharge amount threshold Xd1, the integrated discharge amount in the charge / discharge range R1 has not deviated, so the process proceeds to step S57, where the discharge difference flag Fa41 is cleared (Fa41=0).

[0065] In step S58, the integrated discharge amount Idr2 is subtracted from the integrated discharge amount Idf2 to calculate the difference ΔId2 of the integrated discharge amount in the charge / discharge range R2. In the following step S59, it is determined whether the absolute value of the difference ΔId2 exceeds a predetermined discharge amount threshold Xd2. If it is determined in step S59 that the absolute value of the difference ΔId2 exceeds the discharge amount threshold Xd2, the integrated discharge amount in the charge / discharge range R2 has deviated, so the process proceeds to step S60, where the discharge difference flag Fa42 is set (Fa42=1). On the other hand, if it is determined in step S59 that the absolute value of the difference ΔId2 is equal to or less than the discharge amount threshold Xd2, the integrated discharge amount in the charge / discharge range R2 has not deviated, so the process proceeds to step S61, where the discharge difference flag Fa42 is cleared (Fa42=0).

[0066] In step S62, the integrated discharge amount Idr3 is subtracted from the integrated discharge amount Idf3 to calculate the difference ΔId3 of the integrated discharge amount in the charge / discharge range R3. In the following step S63, it is determined whether the absolute value of the difference ΔId3 exceeds a predetermined discharge amount threshold Xd3. If it is determined in step S63 that the absolute value of the difference ΔId3 exceeds the discharge amount threshold Xd3, the integrated discharge amount in the charge / discharge range R3 has deviated, so the process proceeds to step S64, where the discharge difference flag Fa43 is set (Fa43=1). On the other hand, if it is determined in step S63 that the absolute value of the difference ΔId3 is equal to or less than the discharge amount threshold Xd3, the integrated discharge amount in the charge / discharge range R3 has not deviated, so the process proceeds to step S65, where the discharge difference flag Fa43 is cleared (Fa43=0).

[0067] 15, when the absolute value of the difference ΔId1 in the integrated discharge amount in the charge / discharge range R1 exceeds a predetermined discharge amount threshold Xd1 (symbol a1), the discharge difference flag Fa31 is set (symbol b1). When the absolute value of the difference ΔId2 in the integrated discharge amount in the charge / discharge range R2 exceeds a predetermined discharge amount threshold Xd2 (symbol c1), the discharge difference flag Fa32 is set (symbol d1). When the absolute value of the difference ΔId3 in the integrated discharge amount in the charge / discharge range R3 exceeds a predetermined discharge amount threshold Xd3 (symbol e1), the discharge difference flag Fa33 is set (symbol f1).

[0068] [Active control] Next, active control, which is deterioration equalization control for almost uniformly deteriorating the battery modules 35, 45, will be described. Fig. 16 and Fig. 17 are flowcharts showing an example of an execution procedure of active control, and Fig. 18 is a diagram showing an example of changes in the integrated charge amount and the integrated discharge amount before and after the execution of active control. The flowcharts shown in Fig. 16 and Fig. 17 are connected to each other at the point of reference E. Furthermore, each step of the active control shown in Fig. 16 and Fig. 17 shows a process executed by the processor 70 constituting the control system 60. Furthermore, the active control shown in Fig. 16 and Fig. 17 is a control executed by the control system 60 at a predetermined cycle after the control system 60 is started.

[0069] In the following description, "Icfn" refers to any one of the integrated charge amounts Icf1, Icf2, and Icf3, and "Idfn" refers to any one of the integrated discharge amounts Idf1, Idf2, and Idf3. Also, "Icrn" refers to any one of the integrated charge amounts Icr1, Icr2, and Icr3, and "Idrn" refers to any one of the integrated discharge amounts Idr1, Idr2, and Idr3. Furthermore, "Fa3n" refers to any one of the charge difference flags Fa31, Fa32, and Fa33, and "Fa4n" refers to any one of the charge difference flags Fa41, Fa42, and Fa43.

[0070] 16, in step S70, it is determined whether the above-mentioned passive control flag Fp1 has been reset. In step S71, if it is determined that the passive control flag Fp1 has been set, that is, if it is determined that passive control for eliminating ΔSOC is being executed, the routine is exited without executing active control.

[0071] In step S71, it is determined whether or not both the first determination flag Fa1 and the second determination flag Fa2 are set. Here, as shown in FIG. 11, the first determination flag Fa1 is set when SOCf and SOCr are within the same charge / discharge range R1 to R3. The second determination flag Fa2 is set when the difference ΔSOC between SOCf and SOCr is below the threshold value β. In step S71, if either the first determination flag Fa1 or the second determination flag Fa2 is cleared, that is, if SOCf and SOCr are within different charge / discharge ranges R1 to R3 or if the difference ΔSOC between SOCf and SOCr exceeds the threshold value β, it is not a situation to execute active control, so the routine is exited without executing active control.

[0072] In step S71, if it is determined that both the first judgment flag Fa1 and the second judgment flag Fa2 are set, the process proceeds to step S72, where it is determined whether or not the charge difference flag Fa3n is set for the same charge / discharge range R1 to R3 in which SOCf and SOCr fall. For example, when both SOCf and SOCr fall within the charge / discharge range R1, it is determined whether or not the charge difference flag Fa31 in the charge / discharge range (same range) R1 is set. In step S72, if it is determined that the charge difference flag Fa3n is set, that is, if the first integrated charge amount Icfn and the second integrated charge amount Icrn are separated from each other, the process proceeds to step S73, where active control is started to eliminate the difference between the integrated charge amount Icfn and the integrated charge amount Icrn.

[0073] In step S73, it is determined whether the integrated charge amount Icfn exceeds the integrated charge amount Icrn. In step S73, if it is determined that the integrated charge amount Icfn exceeds the integrated charge amount Icrn, since the integrated charge amount Icfn of the front battery module 35 is large, the process proceeds to step S74, in which the regenerative torque distribution ratio of the front motor 31 and the rear motor 51 is changed from a predetermined reference distribution ratio. That is, for the front motor 31, the allocated regenerative torque is changed to be lowered from the allocated regenerative torque based on the reference distribution ratio, and the charging of the front battery module 35 is suppressed. Also, for the rear motor 51, the allocated regenerative torque is changed to be higher from the allocated regenerative torque based on the reference distribution ratio, and the charging of the rear battery module 45 is promoted. As a result, as shown by the symbol a1 in FIG. 18, the integrated charge amount Icfn and the integrated charge amount Icrn can be brought closer to each other, and the battery modules 35, 45 can be deteriorated in the same manner.

[0074] On the other hand, when it is determined in step S73 that the integrated charge amount Icfn is less than the integrated charge amount Icrn, since the integrated charge amount Icfn of the front battery module 35 is small, the process proceeds to step S75, where the regenerative torque distribution ratio of the front motor 31 and the rear motor 51 is changed from a predetermined reference distribution ratio. That is, for the front motor 31, the allocated regenerative torque is changed to be increased from the allocated regenerative torque based on the reference distribution ratio, and charging of the front battery module 35 is promoted. Also, for the rear motor 51, the allocated regenerative torque is changed to be decreased from the allocated regenerative torque based on the reference distribution ratio, and charging of the rear battery module 45 is suppressed. As a result, as shown by the symbol a1 in FIG. 18, the integrated charge amount Icfn and the integrated charge amount Icrn can be brought closer to each other, and the battery modules 35, 45 can be deteriorated in the same manner.

[0075] Next, the process proceeds to step S76, where it is determined whether or not a discharge difference flag Fa4n is set for the same charge / discharge range in which SOCf and SOCr fall. For example, when both SOCf and SOCr fall within the charge / discharge range R1, it is determined whether or not a discharge difference flag Fa41 for the charge / discharge range (same range) R1 is set. When it is determined in step S76 that the discharge difference flag Fa4n is set, that is, when the first integrated discharge amount Idfn and the second integrated discharge amount Idrn diverge, the process proceeds to step S77, where active control is started to eliminate the difference between the integrated discharge amount Idfn and the integrated discharge amount Idrn.

[0076] In step S77, it is determined whether the accumulated discharge amount Idfn exceeds the accumulated discharge amount Idrn. If it is determined in step S77 that the accumulated discharge amount Idfn exceeds the accumulated discharge amount Idrn, the accumulated discharge amount Idfn of the front battery module 35 is large, so the process proceeds to step S78, in which the powering torque distribution ratio of the front motor 31 and the rear motor 51 is changed from a predetermined reference distribution ratio. That is, for the front motor 31, the allocated powering torque is changed to be lowered from the allocated powering torque based on the reference distribution ratio, and the discharge of the front battery module 35 is suppressed. Also, for the rear motor 51, the allocated powering torque is changed to be increased from the allocated powering torque based on the reference distribution ratio, and the discharge of the rear battery module 45 is promoted. As a result, as shown by the symbol b1 in FIG. 18, the accumulated discharge amount Idfn and the accumulated discharge amount Idrn can be made closer to each other, and the battery modules 35, 45 can be deteriorated in the same manner.

[0077] On the other hand, when it is determined in step S77 that the accumulated discharge amount Idfn is less than the accumulated discharge amount Idrn, since the accumulated discharge amount Idfn of the front-side battery module 35 is small, the process proceeds to step S79, where the powering torque distribution ratio of the front motor 31 and the rear motor 51 is changed from a predetermined reference distribution ratio. That is, for the front motor 31, the allocated powering torque is changed to be increased from the allocated powering torque based on the reference distribution ratio, and the discharge of the front-side battery module 35 is promoted. Also, for the rear motor 51, the allocated powering torque is changed to be decreased from the allocated powering torque based on the reference distribution ratio, and the discharge of the rear-side battery module 45 is suppressed. As a result, as shown by the symbol b1 in FIG. 18, the accumulated discharge amount Idfn and the accumulated discharge amount Idrn can be made closer to each other, and the battery modules 35, 45 can be deteriorated in the same manner.

[0078] As described above, by executing the active control, the integrated charge amount Icfn of the front-side battery module 35 and the integrated charge amount Icrn of the rear-side battery module 45 can be brought closer to each other for each of the charge and discharge ranges R1 to R3. This allows the battery modules 35, 45 to deteriorate in the same manner. Furthermore, by executing the active control, the integrated discharge amount Idfn of the front-side battery module 35 and the integrated discharge amount Idrn of the rear-side battery module 45 can be brought closer to each other for each of the charge and discharge ranges R1 to R3. This allows the battery modules 35, 45 to deteriorate in the same manner.

[0079] [Temperature correction for accumulated charge and discharge amounts] As described above, the front battery control unit 36 ​​calculates the integrated charge amount Icfn by integrating the charge current of the battery module 35, and calculates the integrated discharge amount Idfn by integrating the discharge current of the battery module 35. The rear battery control unit 56 calculates the integrated charge amount Icrn by integrating the charge current of the battery module 45, and calculates the integrated discharge amount Idrn by integrating the discharge current of the battery module 45.

[0080] Incidentally, the deterioration state of the battery modules 35, 45 depends not only on the charge and discharge amount but also on the temperature of the battery modules 35, 45. In other words, when the battery modules 35, 45 are charged and discharged in a high-temperature environment, it is expected that the deterioration state of the battery modules 35, 45 will be more advanced than when the battery modules 35, 45 are charged and discharged in a normal temperature environment, which is lower than a high-temperature environment. In order to accurately reflect such a deterioration state of the battery modules 35, 45, the integrated charge amount Icfn, Icrn and the integrated discharge amount Idfn, Idrn may be corrected based on the temperature of the battery modules 35, 45.

[0081] Here, Fig. 19 is a diagram showing an example of the correction coefficient for correcting the charging current and the discharging current, and Fig. 20 is a diagram showing an example of the accumulation state of the charging current and the accumulation state of the discharging current. As shown in Fig. 19, the correction coefficient is set to be larger as the temperature (hereinafter, referred to as the battery temperature) of the battery modules 35, 45 becomes higher. When calculating the accumulated charging amounts Icfn, Icrn, the charging current multiplied by the correction coefficient is accumulated, and when calculating the accumulated discharging amounts Idfn, Idrn, the discharging current multiplied by the correction coefficient is accumulated.

[0082] That is, as shown in FIG. 20, even if the same charging current flows to the battery modules 35, 45, the higher the battery temperature, the greater the integrated charging amounts Icfn, Icrn. For example, even if the same charging current flows, when the battery temperature is 45° C., the integrated charging amounts Icfn, Icrn are greater than when the battery temperature is 30° C. For example, even if the same charging current flows, when the battery temperature is 60° C., the integrated charging amounts Icfn, Icrn are greater than when the battery temperature is 45° C. Also, as shown in FIG. 20, even if the same discharging current flows from the battery modules 35, 45, the greater the integrated discharging amounts Idfn, Idrn are greater than when the battery temperature is 30° C. For example, even if the same discharging current flows, when the battery temperature is 45° C., the integrated discharging amounts Idfn, Idrn are greater than when the battery temperature is 30° C. For example, even when the same discharge current flows, when the battery temperature is 60° C., the integrated discharge amounts Idfn and Idrn are greater than when the battery temperature is 45° C. This makes it possible to appropriately reflect the effect of the battery temperature on the deterioration state, and to appropriately adjust the deterioration state of the battery modules 35 and 45 by active control.

[0083] The present invention is not limited to the above-described embodiment, and it goes without saying that various modifications are possible without departing from the gist of the present invention. For example, in the above description, the control system 60 is configured by five control units, but the present invention is not limited to this, and the control system 60 may be configured by one control unit, may be configured by two to four control units, or may be configured by six or more control units. In addition, the integrated charge amounts Icfn and Icrn may be integrated charges including the charging current during external charging using an external power source, or may be integrated charges excluding the charging current during external charging.

[0084] In the above description, both passive control and active control are executed, but the present invention is not limited to this, and only passive control may be executed, or only active control may be executed. In the above description, active control is executed for all charge / discharge ranges R1 to R3, but the present invention is not limited to this, and active control may be executed for any of the charge / discharge ranges R1 to R3. Furthermore, the charge amount thresholds Xc1, Xc2, and Xc3 may be the same value or different values. Furthermore, the discharge amount thresholds Xd1, Xd2, and Xd3 may be the same value or different values. In the above description, three charge / discharge ranges R1 to R3 are set for the battery modules 35 and 45, but the present invention is not limited to this, and two charge / discharge ranges may be set for the battery modules 35 and 45, or four or more charge / discharge ranges may be set for the battery modules 35 and 45.

[0085] In the above description, the battery modules 35 and 45 are lithium ion batteries, but the present invention is not limited to this, and any power storage unit may be used as long as the power storage unit has different deterioration characteristics depending on the capacity. The battery modules 35 and 45 shown in the figure are the same type of lithium ion battery, but the present invention is not limited to this, and different types of power storage units may be used as long as the power storage units have similar deterioration characteristics. The upper limit capacities of the battery modules 35 and 45 may be the same, or there may be a slight difference between the upper limit capacities of the battery modules 35 and 45. The lower limit capacities of the battery modules 35 and 45 may be the same, or there may be a slight difference between the lower limit capacities of the battery modules 35 and 45.

[0086] In the illustrated example, one front motor 31 is connected to the left and right front wheels 20, but this is not limited thereto, and one front motor may be connected to one front wheel 20. Similarly, one rear motor 51 is connected to the left and right rear wheels 40, but this is not limited thereto, and one rear motor may be connected to one rear wheel 40. In addition, the illustrated vehicle 11 is an electric vehicle that does not have an engine, but this is not limited thereto, and the vehicle control device of the present invention may be applied to, for example, a series type hybrid vehicle. [Explanation of symbols]

[0087] 10 Vehicle control device 11 Vehicles 20 Front wheel 30 Front-wheel drive system 31 Front motor (first driving motor) 35 Battery module (first storage unit) 40 Rear wheel 50 Rear wheel drive system 51 Rear motor (second driving motor) 55 Battery module (second storage unit) 60 Control System 70 Processors 71 Main memory (memory) 72 Microcontrollers SOCf SOC SOCr SOC ΔSOC difference Taf, Tafx, Tar, Tarx Allocated power torque Tbf, Tbfx, Tbr, Tbrx Allocated regenerative torque α Start threshold (threshold) S1 Boundary value (upper SOC) S4 Boundary value (lower SOC limit) R1, R2, R3 Charge / discharge range (charge / discharge range) Icf, Icf1, Icf2, Icf3, Icfn Accumulated charge amount (1st accumulated charge amount) Icr, Icr1, Icr2, Icr3, Icrn Accumulated charge amount (2nd accumulated charge amount) Idf, Idf1, Idf2, Idf3, Idfn Accumulated discharge amount (1st accumulated discharge amount) Idr, Idr1, Idr2, Idr3, Idrn Accumulated discharge amount (2nd accumulated discharge amount) ΔIc1, ΔIc2, ΔIc3 Difference ΔId1, ΔId2, ΔId3 Difference Xc1, Xc2, Xc3 Charge threshold Xd1, Xd2, Xd3 Discharge threshold

Claims

1. A vehicle control device provided in a vehicle, a front-wheel drive system including a first driving motor mechanically connected to a front wheel and a first power storage body electrically connected to the first driving motor; a rear wheel drive system including a second traction motor mechanically connected to the rear wheels and a second power storage body electrically connected to the second traction motor; a control system including a processor and a memory communicatively connected to each other, the control system controlling the first traction motor and the second traction motor; having the control system changes a torque distribution ratio between the first traction motor and the second traction motor from a reference distribution ratio when a difference between an SOC of the first power storage unit and an SOC of the second power storage unit exceeds a threshold value. Vehicle control device.

2. 2. The vehicle control device according to claim 1, The control system includes: When a difference between the SOC of the first power storage device and the SOC of the second power storage device exceeds the threshold value and the SOC of the first power storage device exceeds the SOC of the second power storage device, A power torque distribution ratio between the first traction motor and the second traction motor is changed from the reference distribution ratio, an allocated powering torque of the first traction motor is increased to a value higher than the allocated powering torque based on the reference distribution ratio, and an allocated powering torque of the second traction motor is decreased to a value lower than the allocated powering torque based on the reference distribution ratio; The control system includes: When a difference between an SOC of the first power storage unit and an SOC of the second power storage unit exceeds the threshold value and the SOC of the first power storage unit is lower than the SOC of the second power storage unit, A power torque distribution ratio between the first traction motor and the second traction motor is changed from the reference distribution ratio, reducing an allocated powering torque of the first traction motor to a value lower than an allocated powering torque based on the reference distribution ratio, and increasing an allocated powering torque of the second traction motor to a value higher than an allocated powering torque based on the reference distribution ratio; Vehicle control device.

3. 2. The vehicle control device according to claim 1, The control system includes: When a difference between the SOC of the first power storage device and the SOC of the second power storage device exceeds the threshold value and the SOC of the first power storage device exceeds the SOC of the second power storage device, A regenerative torque distribution ratio between the first traction motor and the second traction motor is changed from the reference distribution ratio, reducing an allocated regenerative torque of the first traction motor to a value lower than an allocated regenerative torque based on the reference distribution ratio, and increasing an allocated regenerative torque of the second traction motor to a value higher than an allocated regenerative torque based on the reference distribution ratio; The control system includes: When a difference between an SOC of the first power storage unit and an SOC of the second power storage unit exceeds the threshold value and the SOC of the first power storage unit is lower than the SOC of the second power storage unit, A regenerative torque distribution ratio between the first traction motor and the second traction motor is changed from the reference distribution ratio, an allocated regenerative torque of the first traction motor is increased to a value higher than the allocated regenerative torque based on the reference distribution ratio, and an allocated regenerative torque of the second traction motor is decreased to a value lower than the allocated regenerative torque based on the reference distribution ratio; Vehicle control device.

4. The vehicle control device according to any one of claims 1 to 3, a range between a lower limit SOC and an upper limit SOC of the first power storage body and a range between a lower limit SOC and an upper limit SOC of the second power storage body are divided into a plurality of charge / discharge ranges, The control system includes: integrating the charging current of the first power storage body for each of the charge / discharge ranges to calculate a first integrated charge amount; integrating the charging current of the second power storage body for each of the charge / discharge ranges to calculate a second integrated charge amount; The control system includes: In a state where the SOC of the first storage battery and the SOC of the second storage battery are within the same charge / discharge range, When a difference between the first integrated charge amount and the second integrated charge amount in the same range exceeds a charge amount threshold and the first integrated charge amount in the same range exceeds the second integrated charge amount, A regenerative torque distribution ratio between the first traction motor and the second traction motor is changed from the reference distribution ratio, reducing an allocated regenerative torque of the first traction motor to a value lower than an allocated regenerative torque based on the reference distribution ratio, and increasing an allocated regenerative torque of the second traction motor to a value higher than an allocated regenerative torque based on the reference distribution ratio; The control system includes: In a state where the SOC of the first power storage device and the SOC of the second power storage device are within the same charge / discharge range, When a difference between the first integrated charge amount and the second integrated charge amount in the same range exceeds the charge amount threshold and the first integrated charge amount in the same range is lower than the second integrated charge amount, A regenerative torque distribution ratio between the first traction motor and the second traction motor is changed from the reference distribution ratio, an allocated regenerative torque of the first traction motor is increased to a value higher than the allocated regenerative torque based on the reference distribution ratio, and an allocated regenerative torque of the second traction motor is decreased to a value lower than the allocated regenerative torque based on the reference distribution ratio; Vehicle control device.

5. The vehicle control device according to any one of claims 1 to 3, a range between a lower limit SOC and an upper limit SOC of the first power storage body and the second power storage body is divided into a plurality of charge / discharge ranges, The control system includes: integrating the discharge current of the first power storage body for each of the charge / discharge ranges to calculate a first integrated discharge amount; integrating the discharge current of the second power storage body for each of the charge / discharge ranges to calculate a second integrated discharge amount; The control system includes: In a state where the SOC of the first storage battery and the SOC of the second storage battery are within the same charge / discharge range, When a difference between the first accumulated discharge amount and the second accumulated discharge amount in the same range exceeds a discharge amount threshold and the first accumulated discharge amount in the same range exceeds the second accumulated discharge amount, A power torque distribution ratio between the first traction motor and the second traction motor is changed from the reference distribution ratio, reducing an allocated powering torque of the first traction motor to a value lower than an allocated powering torque based on the reference distribution ratio, and increasing an allocated powering torque of the second traction motor to a value higher than an allocated powering torque based on the reference distribution ratio; The control system includes: In a state where the SOC of the first power storage device and the SOC of the second power storage device are within the same charge / discharge range, When a difference between the first accumulated discharge amount and the second accumulated discharge amount in the same range exceeds the discharge amount threshold and the first accumulated discharge amount in the same range is lower than the second accumulated discharge amount, A power torque distribution ratio between the first traction motor and the second traction motor is changed from the reference distribution ratio, an allocated powering torque of the first traction motor is increased to a value higher than the allocated powering torque based on the reference distribution ratio, and an allocated powering torque of the second traction motor is decreased to a value lower than the allocated powering torque based on the reference distribution ratio; Vehicle control device.

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