Vehicle

Abstract

To protect a power storage device from overheating while suppressing a decrease in the driving performance in a vehicle that performs temperature adjustment of the power storage device.SOLUTION: A vehicle comprises: a power storage device; a travel drive unit which generates travel driving force for the vehicle using power from the power storage device; a sensor which monitors a state of the power storage device; a temperature adjustment device which adjusts the temperature of the power storage device; and a control device which controls the travel drive unit and the temperature adjustment device. The control device estimates an open-circuit voltage and an internal resistance of the power storage device on the basis of a detection result of the sensor. The control device calculates, on the basis of the estimated open-circuit voltage and internal resistance and a temperature adjustment capacity of the temperature adjustment device, a control upper limit value of output power of the power storage device such that the heat quantity of the power storage device is less than the temperature adjustment capacity. The control device controls the travel driving force of the vehicle so that the output power of the power storage device does not exceed the control upper limit value.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a vehicle.

Background Art

[0002] For example, Japanese Patent Application Laid-Open No. 2023-114369 (Patent Document 1) discloses a battery temperature adjustment system mounted on a vehicle. This battery temperature adjustment system derives a battery temperature prediction when performing battery cooling control to adjust the temperature of the battery with the temperature adjustment ability of the battery temperature adjustment device according to the vehicle state in the planned driving schedule based on the planned driving schedule of the vehicle. When it is predicted that the battery temperature prediction will overshoot, the battery temperature adjustment amount required to keep the battery temperature below a predetermined temperature is derived, and the battery temperature adjustment amount is allocated before the overshoot occurs.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the battery temperature adjustment system described in Patent Document 1, when the heat generation amount of the battery exceeds the temperature adjustment ability of the battery temperature adjustment device according to the required output of the vehicle, it becomes difficult to prevent the battery temperature from exceeding a predetermined temperature. In this case, in order to protect the battery from overheating, the output of the vehicle is restricted, and there is a concern that the driving performance of the vehicle will be significantly reduced.

[0005] The present disclosure has been made to solve the above problems, and an object of the present disclosure is to protect a power storage device from overheating while suppressing a decrease in driving performance in a vehicle that performs temperature adjustment of the power storage device.

Means for Solving the Problems

[0006] A vehicle according to one aspect of the present disclosure includes a power storage device, a traveling drive unit that generates a traveling driving force of the vehicle using the power of the power storage device, a sensor that monitors the state of the power storage device, a temperature control device that adjusts the temperature of the power storage device, and a control device that controls the traveling drive unit and the temperature control device. The control device estimates the open-circuit voltage and the internal resistance of the power storage device based on the detection result of the sensor. The control device calculates a control upper limit value of the output power of the power storage device such that the heat generation amount of the power storage device is less than the temperature control capacity based on the estimated open-circuit voltage and internal resistance and the temperature control capacity of the temperature control device. The control device controls the traveling driving force of the vehicle so that the output power of the power storage device does not exceed the control upper limit value.

Effect of the Invention

[0007] According to the present disclosure, a control upper limit value of the output power of the power storage device is calculated so that the heat generation amount of the power storage device does not exceed the temperature control capacity of the power storage device, and the traveling driving force of the vehicle is limited according to this control upper limit value. Thereby, a decrease in the traveling performance of the vehicle can be suppressed to the minimum necessary for protecting the power storage device from overheating.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Mode for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and their description will not be repeated.

[0010] FIG. 1 is a diagram showing an example of the overall configuration of a vehicle according to an embodiment of the present disclosure. As shown in FIG. 1, the vehicle 50 includes an inlet 110, a charger / discharger 120, a battery pack 130, a driving unit 140, an electronic control unit (hereinafter also referred to as "ECU (Electronic Control Unit)") 150, an input device 160, a notification device 170, a communication device 180, and drive wheels W.

[0011] The battery pack 130 includes a battery 131, a sensor module (hereinafter also referred to as "sensor MD") 132, and a temperature control device 133. The battery 131 includes a battery that stores electric power for driving. The battery 131 is a secondary battery such as a lithium-ion battery or a nickel-metal hydride battery, for example. The battery 131 corresponds to an example of the "power storage device".

[0012] The sensor MD 132 monitors the state of the battery 131. The sensor MD 132 includes various sensors that detect the state of the battery 131 (such as temperature, current, voltage, etc.), and outputs the detection results to the ECU 150. The ECU 150 can obtain the state of the battery 131 (such as temperature, current, voltage, SOC (State Of Charge), open circuit voltage (OCV: Open Circuit Voltage), and internal resistance) based on the output of the sensor MD 132 (that is, the detection values of various sensors).

[0013] The temperature control device 133 is configured to adjust the temperature of the battery 131. The temperature control device 133 includes a heating device that heats the battery 131 and a cooling device that cools the battery 131. For example, the heating device is an electric heater, and the cooling device is a radiator and a cooling fan. The temperature control device 133 is controlled by the ECU 150. When the ECU 150 raises the temperature of the battery 131, it stops the cooling device and drives the heating device. When the ECU 150 lowers the temperature of the battery 131, it stops the heating device and drives the cooling device. The heating device and the cooling device are configured to be drivable by either the electric power supplied from the vehicle 50 to the inlet 110 or the electric power supplied from the battery 131.

[0014] The EVSE (Electric Vehicle Supply Equipment) 40 includes a charging cable 42. By connecting the connector 43 at the tip of the charging cable 42 to the inlet 110, the EVSE 40 and the vehicle 50 are electrically connected, enabling the transfer of electric power.

[0015] The charger / discharger 120 is located between the inlet 110 and the battery 131. The charger / discharger 120 has a power conversion circuit, which converts the AC power supplied from the EVSE 40 into DC power and outputs it to the battery 131, and is also configured to convert the DC power supplied from the battery 131 into AC power and output it to the inlet 110.

[0016] The driving unit 140 includes a PCU (Power Control Unit) and an MG (Motor Generator), and drives the vehicle 50 using the electric power stored in the battery 131. The PCU includes an inverter and a converter, and is controlled by the ECU 150. The MG is, for example, a three-phase AC motor generator, and is driven by the PCU to rotate the drive wheels W. The PCU drives the MG using the electric power supplied from the battery 131. The MG supplies the regenerated electric power to the battery 131.

[0017] The ECU 150 is configured to include a processor 151, a RAM (Random Access Memory) 152, and a storage device 153. The processor 151 is, for example, a CPU (Central Processing Unit). The RAM 152 functions as a working memory that temporarily stores the data processed by the processor 151. The storage device 153 includes a ROM (Read Only Memory) and a non-volatile memory, and stores programs and information (maps, mathematical formulas, various parameters, etc.) used in the programs. By the processor 151 executing the programs stored in the storage device 153, various controls in the ECU 150 are executed. However, the various controls in the ECU 150 are not limited to being executed by software, and can also be executed by dedicated hardware (electronic circuits).

[0018] The input device 160 receives the user's input and outputs a signal for the user's operation to the ECU 150. The input device 160 is, for example, the operation unit of a car navigation system. The notification device 170 is a device that notifies the user of various information in response to a request from the ECU 150. The notification device 170 is, for example, the display unit of a car navigation system. The communication device 180 includes various communication I / Fs (interfaces). The communication device 180 includes a communication I / F for wireless communication with external devices of the vehicle 50.

[0019] As described above, the vehicle 50 is a vehicle powered by the power of the battery 131. The vehicle 50 may be an electric vehicle or a plug-in hybrid vehicle. During the running of the vehicle 50, the battery 131 generates heat by charging and discharging. FIG. 2 is a diagram showing an example of the relationship between the vehicle load, the heat generation amount of the battery 131, and the vehicle speed. The horizontal axis of FIG. 2 indicates the vehicle speed, and the vertical axis indicates the vehicle load and the heat generation amount of the battery 131. The vehicle load represents the power (battery output power) output from the battery 131 to the running drive unit 140.

[0020] As shown in FIG. 2, the vehicle load (battery output power) increases as the vehicle speed increases. In a certain aspect, the vehicle load increases with the cube of the vehicle speed. As the vehicle load increases, the heat generation amount of the battery 131 also increases. In a certain aspect, since the heat generation amount of the battery 131 increases with the square of the vehicle load, the heat generation amount of the battery 131 will increase with the sixth power of the vehicle speed. The ECU 150 drives the temperature control device 133 to cool the battery 131 so that the temperature of the battery 131 does not exceed a predetermined allowable temperature range. However, if the heat generation amount of the battery 131 exceeds the temperature control ability (cooling ability) of the battery 131, there is a possibility of overheating of the battery 131.

[0021] In order to protect the battery 131 from overheating, in the present embodiment, the vehicle load is restricted so that the heat generation amount of the battery 131 is less than the temperature control ability (cooling ability) of the battery 131. As shown in FIG. 2, by reducing the vehicle speed due to the restriction of the vehicle load, the heat generation amount of the battery 131 can be significantly reduced. The ECU 150 is configured to set the control upper limit value Wout of the vehicle load according to the temperature control ability (cooling ability) of the battery 131. Thereby, it is possible to protect the battery 131 from overheating while suppressing the decrease in vehicle speed (decrease in running performance) to the minimum necessary.

[0022] FIG. 3 is a flowchart showing the processing procedure of the output control of the battery 131 in the ECU 150. The processing shown in this flowchart is executed when a predetermined condition is satisfied (for example, every control cycle). Hereinafter, the step will be abbreviated as "S".

[0023] In S01, the ECU 150 calculates the temperature control ability of the battery 131. For example, the ECU 150 calculates the temperature control ability of the battery 131 based on the temperature and flow rate of the refrigerant in the cooling device (radiator, cooling fan, etc.) included in the temperature control device 133, the temperature of the battery 131, and the like. As a method for calculating the temperature control ability, a known method can be adopted.

[0024] In S02 and S03, the ECU 150 estimates the internal resistance R and OCV of the battery 131 based on the output of the sensor MD132 (detection values of various sensors). As a method for estimating the internal resistance R and OCV, a known method can be adopted. For example, the ECU 150 can estimate the internal resistance R from the change rate of the current with respect to the voltage of the battery 131, and estimate the OCV by subtracting the voltage related to the internal resistance R from the voltage of the battery 131.

[0025] In S04, the ECU 150 calculates the control upper limit value Wout of the battery output power such that the heat generation amount of the battery 131 is less than the temperature control ability of the battery 131 calculated in S01. In S04, the ECU 150 calculates the control upper limit value Wout of the battery output power using Equation (1).

[0026] [Number]

[0027] P is the battery output power (vehicle load), and P L is the heat generation amount of the battery 131, and K is the heat generation coefficient. The heat generation coefficient K is given by the following formula (2).

[0028] [Number]

[0029] R is the internal resistance of the battery 131, and V is the OCV of the battery 131. Formula (1) represents the relationship between the battery output power P and the heat generation amount P L of the battery 131. The first term on the right side of formula (1) is obtained by deriving the power consumption of the battery 131 using the heat generation coefficient K from the heat generation amount P L of the battery 131. The power stored in the battery 131 is consumed by the power output from the battery 131 to the running drive unit 140 (i.e., the battery output power) and the generation inside the battery 131. By subtracting the heat generation amount P L of the battery 131 from the power consumption of the battery 131, the battery output power P can be obtained.

[0030] The ECU 150 substitutes the temperature control ability of the battery 131 calculated by S01 into P L in formula (1) to calculate the battery output power P when the heat generation amount P L of the battery 131 is equal to the temperature control ability. Then, the ECU 150 sets the calculated battery output power P as the control upper limit value Wout of the battery output power when the heat generation amount of the battery 131 is less than the temperature control ability. By setting the battery output power when the heat generation amount P L of the battery 131 is equal to the temperature control ability as the control upper limit value Wout of the battery output power and limiting the battery output power, it is possible to suppress the decrease in the running performance of the vehicle 50 to the necessary minimum for protecting the battery 131 from overheating.

[0031] In S05, the ECU 150 calculates the vehicle required output (the required output power of the battery 131) based on the accelerator opening degree and the like, and compares the calculated vehicle required output with the control upper limit value Wout of the battery output power calculated in S04. When the vehicle required output exceeds the control upper limit value Wout (when the determination in S05 is YES), the ECU 150 controls the driving unit 140 in S06 so that the battery output power becomes equal to or less than the control upper limit value Wout, thereby restricting the vehicle load. When the vehicle required output is equal to or less than the control upper limit value Wout (when the determination in S05 is NO), the ECU 150 controls the driving unit 140 according to the vehicle required output.

[0032] As described above, according to the vehicle according to the present embodiment, since it is possible to limit the vehicle load (battery output power) according to the temperature control ability of the battery 131, it is possible to suppress the decrease in the running performance of the vehicle to the minimum necessary for protecting the power storage device from overheating.

[0033] Note that, for the output control of the battery 131 according to the above-described embodiment, the following configuration examples can be appropriately combined and applied.

[0034] (1) In the calculation process of the temperature control ability of the battery 131 (S01 in FIG. 3), the temperature control ability by the temperature control device 133 and the temperature control ability by the heat capacity of the battery 131 can be added to calculate the temperature control ability of the battery 131. This is because when the difference between the temperature of the battery 131 and the allowable upper limit temperature is large, heat generation corresponding to the product of this temperature difference and the heat capacity of the battery 131 can be allowed.

[0035] Note that the temperature control ability by the heat capacity can be obtained by (allowable upper limit temperature - current battery temperature) × (heat capacity of the battery 131) / (target running time). The ECU 150 can acquire the user input of the target running time to the input device 160. Alternatively, the ECU 150 can estimate the target running time based on the running route of the vehicle 50 received by the input device 160.

[0036] (2) Even when the vehicle required load exceeds the control upper limit value Wout of the battery output power (when the determination at S05 is YES), if the time for which the vehicle required load exceeds the control upper limit value Wout is shorter than a specified time determined in advance, the ECU 150 can be configured not to limit the vehicle load (battery output power) at S06. In a situation where the vehicle required load increases only for a short time, such as during a wide open throttle (WOT) operation, the temperature rise of the battery 131 is suppressed by the heat capacity of the battery 131. Therefore, by not limiting the vehicle load, the acceleration performance of the vehicle 50 can be ensured.

[0037] (3) The ECU 150 can be configured not to limit the vehicle load (battery output power) according to the driving mode of the vehicle 50. For example, in the case of a driving mode aimed at limit driving that uses up the power of the battery 131, such as a circuit mode for driving on a circuit, by not limiting the vehicle load, the driving performance required by the user can be realized.

[0038] (4) According to the output control of the battery 131 according to the present embodiment, it is possible to suppress the decrease in vehicle speed in a situation where the vehicle 50 travels for a long time to the minimum necessary for overheat protection of the battery 131. However, some users may be dissatisfied with the limitation of the vehicle load. For this, a lower limit value can be set for the control upper limit value Wout of the battery output power, and the control upper limit value Wout can be set to be equal to or higher than this lower limit value. According to this, although it may become difficult for the vehicle 50 to travel for the initial target time, the user satisfaction can be prioritized.

[0039] (5) Note that the lower limit value of the control upper limit value Wout of the battery output power described above can be changed according to the driving mode of the vehicle 50. This is because the limitation of the vehicle load that the driver is likely to be dissatisfied with may vary depending on the driving mode.

[0040] The embodiments disclosed herein should be considered as illustrative in all respects and not restrictive. The scope of the present disclosure is defined by the scope of the claims rather than the description of the above embodiments, and it is intended that all modifications within the meaning and scope equivalent to the scope of the claims be included.

Explanation of Reference Numerals

[0041] 50 Vehicle, 130 Battery pack, 131 Battery, 132 Sensor MD, 133 Temperature control device, 140 Driving unit, 150 ECU.

Claims

【Claim 1】 A vehicle, comprising: a power storage device; a traveling drive unit that generates a traveling driving force of the vehicle using the power of the power storage device; a sensor that monitors the state of the power storage device; a temperature control device that controls the temperature of the power storage device; a control device that controls the traveling drive unit and the temperature control device, wherein the control device: estimates an open-circuit voltage and an internal resistance of the power storage device based on a detection result of the sensor; calculates a control upper limit value of the output power of the power storage device for the heat generation amount of the power storage device to be less than the temperature control ability based on the estimated open-circuit voltage and internal resistance and the temperature control ability of the temperature control device; controls the traveling driving force of the vehicle so that the output power of the power storage device does not exceed the control upper limit value.

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