control device

Abstract

The present invention provides a control device that can suppress power consumption for raising the battery temperature of an electric vehicle. [Solution] A hybrid ECU 10 applied to a vehicle 1 comprising a motor 2 that drives the vehicle 1 using the power of a battery 5 and can charge the battery 5 with regenerative power when the vehicle 1 is decelerating, and a warm-up device 6 that warms up the battery 5, the ECU 10 including a warm-up control unit 11 that controls the warm-up device 6 so that the battery 5 rises to a predetermined target temperature, and a temperature setting unit 12 that lowers the target temperature as the regenerative force from the motor 2 becomes stronger.

Description

Technical Field

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[0001] The present invention relates to a control device for an electric vehicle.

Background Art

[0002] An electric vehicle equipped with a battery for driving may have a decrease in the output of the battery and a significant decrease in the vehicle's power performance in a low-temperature environment. Therefore, in conventional electric vehicles, a temperature-raising device for raising the temperature of the battery is provided when the temperature of the battery decreases. For example, in the prior art disclosed in Patent Document 1, the temperature of the battery is raised by circulating a heat medium heated by an electric heater through the battery.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the prior art as described above, since the power of the battery itself is consumed to raise the temperature of the battery, the power of the battery cannot necessarily be used efficiently, and there is room for improvement in terms of energy-saving performance.

[0005] The present invention has been made in view of such problems, and an object thereof is to provide a control device capable of suppressing power consumption for raising the temperature of a battery of an electric vehicle.

Means for Solving the Problems

[0007] The control device of the present invention, in an electric vehicle equipped with a motor capable of traction control and regenerative control by exchanging power with a battery, controls a warm-up device that raises the low temperature battery to a target temperature, lowering the target temperature as the motor's regenerative force increases. As a result, the control device can suppress the output of the warm-up device as the battery is heated by self-heating due to the regenerative current, thereby reducing the power required to warm up the battery. Therefore, the control device according to the present invention can suppress the power consumption required to raise the battery temperature of an electric vehicle. [Brief explanation of the drawing]

[0008] [Figure 1] This is a block diagram relating to battery warm-up control of a vehicle to which the control device described herein is applied. [Figure 2] This is an example of the relationship between regeneration level and warm-up level. [Figure 3] This flowchart shows the procedure for setting the target temperature in warm-up control. [Modes for carrying out the invention]

[0009] The embodiments will now be described in detail with reference to the drawings. Figure 1 is a block diagram relating to battery warm-up control of a vehicle 1 to which the control device according to this disclosure is applied. Vehicle 1 is a plug-in hybrid vehicle (PHEV) or hybrid vehicle (hereinafter referred to as a hybrid vehicle) that can be charged from an external source and can supply power to an external source, and its main components related to battery warm-up control include a motor 2, an MCU 3, a battery pack 4, a battery 5, a warm-up device 6, a BMU 7, a vehicle system ECU 8, a paddle shift 9, and a hybrid ECU 10 as a "control device". In addition to the above configuration, vehicle 1 is also equipped with various components that are known to be installed in hybrid vehicles, such as an engine (internal combustion engine) which is not shown. Furthermore, vehicle 1 may be an electric vehicle (pure EV) that does not have an engine (internal combustion engine).

[0010] Motor 2 is a so-called motor generator that can provide power to drive vehicle 1 when electricity is supplied to it, and can also generate electricity by regenerating power when vehicle 1 is decelerating.

[0011] The MCU3 is an electronic control unit that exchanges power with the motor 2. It converts the DC power supplied from the battery 5 into AC power and outputs it to the motor 2, and converts the AC power regenerated from the motor 2 into DC power to charge the battery 5. The MCU3 also controls the operation of the motor drive and regenerative drive by controlling the motor torque of the motor 2.

[0012] The battery pack 4 is an energy storage module that integrates a battery 5, a warm-up device 6, a voltage sensor Sv, a current sensor Sc, and a temperature sensor St. The battery 5 is a lithium-ion battery that primarily outputs power used for driving the vehicle 1 and can be charged by regenerative power from the motor 2. The warm-up device 6 is a heating device, such as an electric heating element, that can warm up the battery 5 by generating heat through the application of electricity. The voltage, current, and temperature of the battery 5 are measured by the voltage sensor Sv, the current sensor Sc, and the temperature sensor St, respectively.

[0013] The BMU7 is an electronic control unit that calculates the State of Charge (SOC) and manages the state of the battery 5 by obtaining the voltage, current, and temperature of the battery 5 from the battery pack 4, respectively.

[0014] The vehicle system ECU8 is an electronic control unit for controlling the vehicle body, including the engine and brake system (none of which are shown), and acquires the vehicle speed (vehicle speed) of the vehicle 1 measured by the vehicle speed sensor Ss.

[0015] The paddle shift 9 is a regenerative force control unit for the driver to select the regenerative force (regenerative braking force) during regenerative braking of the motor 2, as will be described in detail later. In this embodiment, it is provided on the steering wheel W of the vehicle 1 as a regenerative force increase button 9(+) and a regenerative force decrease button 9(-). Note that the regenerative force control unit is not limited to the paddle shift 9, but may be a shift lever or other types of push buttons.

[0016] The hybrid ECU 10, acting as a "control device," is an electronic control unit that controls the entire vehicle 1 by sending and receiving information with each component of the vehicle 1. It consists of input / output devices, memory devices (ROM, RAM, non-volatile RAM, etc.), a central processing unit (CPU), etc. More specifically, the hybrid ECU 10 acquires the state of the battery 5 via the BMU 7, acquires the vehicle speed of the vehicle 1 via the vehicle system ECU 8, and controls the discharge control from the battery 5 to the motor 2 in power control and the charging control from the battery 5 to the motor 2 in regenerative control via the MCU 3. Furthermore, the hybrid ECU 10 acquires the driver's regenerative operation via the paddle shift 9.

[0017] Furthermore, the hybrid ECU 10 according to this embodiment includes a warm-up control unit 11, a temperature setting unit 12, a regenerative power setting unit 13, and a storage unit 14 as a functional module related to battery warm-up, and controls the warm-up device 6 via the BMU 7 when the battery 5 is in a low temperature state to raise the temperature to a desired target temperature.

[0018] The warm-up control unit 11 controls the drive / stop of the warm-up device 6 and performs temperature rise output control during drive control. The temperature setting unit 12 sets a target temperature for the battery 5 when driving the warm-up device 6. The regenerative force setting unit 13 sets the regenerative force of the motor 2 based on the operation of the paddle shift 9 and instructs the MCU 3 to perform motor torque control during regenerative control. The storage unit 14 stores in advance the target temperature of the battery 5 that the temperature setting unit 12 should set according to the regenerative force set by the regenerative force setting unit 13, that is, the relationship between the regenerative force and the target temperature.

[0019] Figure 2 is an example of the relationship between the regeneration level and the warm-up level. The regenerative braking force of the motor 2 is set to, for example, six regeneration levels of B0 to B5 according to its magnitude. The regenerative braking force of B0 is 0, and the regenerative braking force is set in the order of B0 < B1 < B2 < B3 < B4 < B5. The regeneration level B2 is set when the driver puts the shift lever of the vehicle 1 into the drive range (D). Also, at this time, if the driver presses the regenerative force increase button 9(+) of the paddle shift 9 once, for example, it is switched to the regeneration level B3.

[0020] In addition, the regeneration level is associated with the warm-up level for the battery 5, and it is set such that the higher the regeneration level, the lower the warm-up level. That is, when the regeneration level is high, as the regeneration current increases, the self-heating of the battery 5 also increases, so the power supplied to the warm-up device 6 can be reduced to suppress power consumption.

[0021] In addition, a target temperature for the battery 5 is set for each warm-up level, and they are associated such that the lower the warm-up level, the lower the target temperature, and are stored in advance in the storage unit 14. That is, when the regenerative force is selected, the hybrid ECU 10 reads out the target temperature corresponding to the regenerative force from the storage unit 14, and can give an instruction to the warming device 6 to increase the temperature at a smooth response speed without calculating the target temperature each time. Further, since the target temperature can be automatically switched in conjunction with the switching of the regenerative force, the driver does not need to switch the target temperature each time the regenerative force of the motor 2 is changed, and thus can operate the vehicle 1 comfortably.

[0022] Next, the warm-up control procedure executed by the hybrid ECU 10 will be described. FIG. 3 is a flowchart showing the procedure for setting the target temperature in the warm-up control. When the battery 5 is at a low temperature, the hybrid ECU 10 can improve the power consumption efficiency associated with the warm-up of the battery 5 by setting the target temperature for the warming device 6 based on this flowchart.

[0023] First, when the vehicle 1 is started by controlling the ignition of the vehicle 1 to be ON (step S1), the hybrid ECU 10 acquires the temperature of the battery 5 from the temperature sensor St and compares it with a predetermined reference temperature (step S2). Here, the reference temperature is arbitrarily set in advance, for example, as the lower limit value of the recommended use temperature range for the battery 5. That is, when the temperature of the battery 5 is lower than the reference temperature, the hybrid ECU 10 determines that the battery 5 needs to be warmed up.

[0024] Next, when the temperature of the battery 5 exceeds the reference temperature (No in step S2), the hybrid ECU 10 maintains the warming device 6 in a stopped state as being unnecessary for warming up, suppresses power consumption, and repeats the comparison between the battery temperature and the reference temperature at regular intervals to continue temperature monitoring.

[0025] On the other hand, if the temperature of the battery 5 is below the reference temperature (Yes in step S2), the hybrid ECU 10 performs an initial warm-up level setting for the battery 5 (step S3). Specifically, the regenerative force setting unit 13 selects the standard regenerative level B2, and the temperature setting unit 12 reads the temperature corresponding to the standard warm-up level from the memory unit 14 and sets it as the target temperature for the battery 5.

[0026] Next, the hybrid ECU 10 determines whether the regeneration level has been changed by the driver via the paddle shift 9 (step S4). If the regeneration level has not been changed, the hybrid ECU 10 maintains the regeneration level and target temperature (No in step S4).

[0027] Meanwhile, when the regenerative braking level is changed (Yes in step S4), the hybrid ECU 10 performs control to change the warm-up setting of the battery 5 (step S5). More specifically, the regenerative braking force setting unit 13 reads the temperature corresponding to the changed regenerative braking force from the storage unit 14, and the temperature setting unit 12 sets this temperature as the new target temperature.

[0028] Furthermore, the hybrid ECU 10 calculates the difference between the acquired battery temperature 5 and a predetermined reference temperature (step S6). The temperature setting unit 12 then performs a correction to lower the target temperature set in step S5, assuming that the smaller the difference between the battery temperature and the reference temperature, the lower the warm-up level can be. Conversely, the temperature setting unit 12 also performs a correction to raise the target temperature set in step S5, assuming that the larger the difference between the battery temperature and the reference temperature, the higher the warm-up level needs to be set (step S7).

[0029] Furthermore, the hybrid ECU 10 obtains the vehicle speed of vehicle 1 from the vehicle speed sensor Ss (step S8) and corrects the warm-up setting of the battery 5 according to the vehicle speed (step S9). In other words, the temperature setting unit 12 assumes that the higher the vehicle speed, the longer it takes for vehicle 1 to decelerate, and therefore the greater the rise in battery temperature due to regenerative braking, and performs a correction to lower the target temperature set in step S7.

[0030] The hybrid ECU 10 then obtains parameters related to the charge state of the battery 5 via the MBU 7 (step S10) and corrects the warm-up setting of the battery 5 according to these parameters (step S11). Here, the parameters related to the charge state are the battery voltage obtained by the voltage sensor Sv, but may also be other indicators such as the SOC calculated by the BMU 7.

[0031] The temperature setting unit 12 sets an upper limit for the target temperature in accordance with the parameter to prevent the battery 5 from overcharging. Therefore, if the target temperature set in step S9 exceeds the upper limit, the temperature setting unit 12 corrects the upper limit to the target temperature, thereby suppressing the charging power during regeneration and protecting the battery 5 from overcharging. On the other hand, if the target temperature is below the upper limit, the temperature setting unit 12 maintains the target temperature set in step S9 without changing it.

[0032] Furthermore, the control from step S6 to step S11 may be repeated at regular intervals (for example, every few ms to a few seconds). In this case, the temperature setting unit 12 can adjust the target temperature as needed. The hybrid ECU 10 then optimizes the target temperature of the battery 5 according to the driver's intention and the state of the vehicle 1 by repeatedly executing the control from step S4 onward during the period when the vehicle 1's ignition is ON (No in step S12). At this time, if the temperature of the battery 5 exceeds the reference temperature, the warm-up device 6 is stopped regardless of the set target temperature, thereby preventing unnecessary power consumption. The hybrid ECU 10 then terminates the series of procedures when the ignition is switched OFF (Yes in step S12).

[0033] As described above, the hybrid ECU 10 according to this disclosure, in a vehicle 1 equipped with a motor 2 capable of traction control and regenerative control by exchanging power with a battery 5, controls a warm-up device 6 that raises the low temperature battery 5 to a target temperature, lowering the target temperature as the regenerative force of the motor 2 increases. As a result, the hybrid ECU 10 can suppress the output of the warm-up device 6 as the battery 5 is heated by self-heating due to regenerative current, thereby reducing the power used to warm up the battery 5. Therefore, the hybrid ECU 10 according to this disclosure can suppress the power consumption for raising the battery temperature of an electric vehicle.

[0034] Furthermore, the hybrid ECU 10 reads the target temperature for raising the temperature of the warm-up device 6 from the memory unit 14 when regenerative operation starts, allowing it to issue a temperature-raising instruction to the warm-up device 6 with a smooth response speed without having to calculate the target temperature each time. In addition, the driver does not need to switch the target temperature each time the regenerative force of the motor 2 is changed, allowing for comfortable operation of the vehicle 1.

[0035] Furthermore, the hybrid ECU 10 sets a lower target temperature the higher the vehicle speed 1 is traveling at. In this case, the higher the travel speed, the longer it takes for vehicle 1 to decelerate, and the greater the self-heating of the battery 5. Therefore, the hybrid ECU 10 can suppress the power consumption of the battery 5 by reducing the output of the warm-up device 6.

[0036] Furthermore, the hybrid ECU 10 acquires parameters related to the charge state of the battery 5 and sets an upper limit for the target temperature to prevent the battery 5 from being overcharged, thereby reducing the risk of the battery 5 being damaged by overcharging. Furthermore, the hybrid ECU 10 can suppress power consumption of the battery 5 by stopping the warm-up device 6 regardless of the target temperature if the battery 5 temperature exceeds the reference temperature, thereby avoiding driving the warm-up device 6 until sufficient output can be obtained from the battery 5. [Explanation of symbols]

[0037] 1 vehicle 2 motors 5 batteries 6. Warm-up device 9 paddle shifters 9(+) Regenerative Power Increase Button 9(-) Regenerative braking reduction button 10 Hybrid ECU 11 Warm-up control unit 12 Temperature setting section 13th Generation Student Development Department 14 Storage section

Claims

1. A control device applied to a vehicle comprising a motor that drives the vehicle using battery power and can charge the battery with regenerative power when the vehicle is decelerating, and a warm-up device for warming up the battery, A warm-up control unit controls the warm-up device so that the battery reaches a predetermined target temperature, A control device including a temperature setting unit that lowers the target temperature as the regenerative force from the motor becomes stronger.

2. A control device according to claim 1, which is applied to a vehicle having a regenerative force operating unit for adjusting the regenerative force of the motor, A regenerative force setting unit sets the regenerative force of the motor based on the operation of the regenerative force operation unit, The system includes a storage unit that stores in advance the target temperature set according to the regenerative force, The warm-up control unit is a control device that raises the temperature of the warm-up device to the target temperature read from the memory unit at the start of the regenerative operation.

3. The control device according to claim 1 or 2, wherein the temperature setting unit acquires the vehicle's travel speed and sets the target temperature lower as the travel speed increases.

4. The control device according to claim 1 or 2, wherein the temperature setting unit acquires parameters relating to the charge state of the battery and sets an upper limit value for the target temperature in accordance with the parameters so that the battery does not become overcharged.

5. The control device according to claim 1 or 2, wherein the temperature setting unit, when the temperature of the battery falls below a predetermined reference temperature, sets the target temperature lower the smaller the difference between the reference temperature and the battery temperature, and sets the target temperature higher the larger the difference.

6. The control device according to claim 1 or 2, wherein the warm-up control unit controls the warm-up device so that the battery reaches the target temperature when the battery temperature falls below a predetermined reference temperature, and stops the warm-up device regardless of the target temperature when the battery temperature exceeds the reference temperature.

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