Electric vehicle control method and electric vehicle control system

Abstract

Provided is a method for controlling an electric vehicle in which power is supplied and received between a drive motor and a battery, and the charging / discharging power of the battery is limited when the temperature of the battery exceeds a prescribed first upper limit temperature, said method comprising: controlling the charging / discharging power of the battery on the basis of information on a road facing a charging site at which the battery is charged; the vehicle is driven from the charging station by predicting whether the vehicle is driven in a low-load driving mode in which the vehicle is driven in a state in which the load of the battery is low or in a high-load driving mode in which the vehicle is driven in a state in which the load of the battery is higher than the low load, and when the vehicle is predicted to be driven in the high-load driving mode, the vehicle is driven from the charging station. When the traveling mode is predicted to be low-load traveling, the upper limit temperature of the battery when the battery is charged is set to a first upper limit temperature, and when the traveling mode is predicted to be low-load traveling, the upper limit temperature of the battery when the battery is charged is set to a second upper limit temperature higher than the first upper limit temperature and lower than the heat-resistant temperature of the battery.

Description

Technical Field

[0001] The present invention relates to a control method for an electric vehicle and a control system for an electric vehicle. Background Art

[0002] JP2019-160423A discloses the following: determining whether a battery mounted on a vehicle needs to be charged, and when it is determined that charging is required, controlling the temperature of the battery until the charger is connected to the vehicle. Summary of the Invention

[0003] When the battery is rapidly charged, the temperature of the battery tends to rise. In addition, when the temperature of the battery rises due to charging until just before output limitation is applied, and then, for example, rapid acceleration is performed immediately after the rise, it is possible that the temperature of the battery further rises due to this and output limitation is applied.

[0004] To avoid this problem, it is also considered to set the upper limit temperature of the battery during charging to be low. However, since there is a correlation between the temperature during charging and the charging rate of the battery, if the upper limit temperature is set low, the charging rate when the battery is fully charged is also set low. Thus, when the vehicle travels at a low acceleration or low speed after the battery is charged, the rise in the temperature of the battery is suppressed, so there is no need to set the upper limit temperature low during battery charging, and the charging rate when the battery is fully charged can be set relatively high accordingly. Nevertheless, the upper limit temperature of the battery during charging and the charging rate of the battery are set lower than necessary, which causes discomfort to the driver.

[0005] Therefore, an object of the present invention is to provide a control method for an electric vehicle and a control system for an electric vehicle that can appropriately set the charging rate when the battery is fully charged by controlling the upper limit temperature of the battery based on the driving state of the vehicle after battery charging.

[0006] According to a certain aspect of the present invention, a control method for an electric vehicle supplies and receives electric power between a drive motor and a battery, and restricts the charge and discharge power of the battery when the temperature of the battery exceeds a specified first upper limit temperature. Regarding the control method, based on information about the road leading to a charging station for charging the battery, it is predicted which driving mode the vehicle will use to drive from the charging station, i.e., low-load driving in which the vehicle travels in a state of low load on the battery or high-load driving in which the vehicle travels in a state of high load greater than the low load. Moreover, when the predicted driving mode is high-load driving, the upper limit temperature of the battery during charging is set to the first upper limit temperature, and when the predicted driving mode is low-load driving, the upper limit temperature of the battery during charging is set to a temperature higher than the first upper limit temperature and lower than the heat-resistant temperature of the battery, which is the second upper limit temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 FIG. is a block diagram for explaining the structure of a vehicle of a control system for an electric vehicle to which the present embodiment is applied.

[0008] Figure 2 FIG. is a block diagram of a control system for an electric vehicle according to the present embodiment.

[0009] Figure 3 FIG. is a graph showing the relationship between the temperature of the battery and the input / output characteristics of the battery.

[0010] Figure 4 FIG. is a graph showing the relationship between the state of charge (SOC) of the battery and the input characteristics of the battery.

[0011] Figure 5 FIG. is a flowchart of a control system for an electric vehicle according to the present embodiment.

[0012] Figure 6 FIG. is a timing chart when it is predicted that the vehicle will travel at high load (rapid acceleration start) after charging the battery in the control system for an electric vehicle according to the present embodiment.

[0013] Figure 7 FIG. is a timing chart when it is predicted that the vehicle will travel at low load (low acceleration start) after charging the battery in the control system for an electric vehicle according to the present embodiment. DETAILED DESCRIPTION OF THE EMBODIMENT

[0014] [Structure of Vehicle 100]

[0015] Figure 1It is a block diagram for explaining the structure of a vehicle 100 of a control system for an electric vehicle to which this embodiment is applied. The vehicle 100 is an electric vehicle. An electric vehicle refers to a vehicle that has a drive motor (hereinafter simply referred to as motor 4) as a drive source and travels by generating a driving force caused by the torque generated by the motor 4 on one or more wheels. Therefore, in addition to so-called electric vehicles, electric vehicles also include hybrid vehicles that use both the motor 4 and an engine as drive sources. For example, electric vehicles also include hybrid vehicles that use the motor 4 as a drive source for either the front wheels or the rear wheels and use the engine as a drive source for the other wheels. In addition, a four-wheel drive vehicle refers to a vehicle that uses four wheels as drive wheels 9. In addition to vehicles that always use four wheels as drive wheels 9, four-wheel drive vehicles also include vehicles that can switch between two-wheel drive and four-wheel drive, such as so-called front-wheel drive or rear-wheel drive. In addition, a four-wheel drive vehicle can sometimes link a part of the four wheels and control them as drive wheels 9, and sometimes control the four wheels as independently driven drive wheels 9. Therefore, in this embodiment, an electric four-wheel drive vehicle refers to a vehicle 100 that travels by generating a driving force caused by the torque generated by the motor 4 on a part or all of the four wheels.

[0016] As Figure 1 shown, the vehicle 100 is an electric four-wheel drive vehicle, but it can also be an electric two-wheel drive based only on the front wheels or an electric two-wheel drive based only on the rear wheels. The vehicle 100 has a front drive system fds, a rear drive system rds, a battery 1, and a controller 2 (control unit).

[0017] The front drive system fds receives power supply from the battery 1 and drives the front wheels 9f under the control of the controller 2. The front drive system fds includes a front inverter 3f, a front drive motor 4f, a front reducer 5f, a front rotation sensor 6f, a front drive shaft 8f, the front wheels 9f, etc. The suffix f indicates the structure on the front side. The front wheels 9f are a pair of wheels that are relatively in front of the vehicle 100 among the four wheels that the vehicle 100 has. The front of the vehicle 100 refers to a specified direction formally defined according to the orientation of the driver's seat, etc. The front drive system fds makes the front wheels 9f act as drive wheels 9 that generate the driving force of the vehicle 100.

[0018] The rear drive system rds receives power supply from the battery 1 and drives the rear wheels 9r under the control of the controller 2. The rear drive system rds symmetrically has a rear inverter 3r, a rear drive motor 4r, a rear reduction gear 5r, a rear rotation sensor 6r, a rear drive shaft 8r, and rear wheels 9r with respect to the front drive system fds. The suffix r indicates the structure on the rear side. The rear wheels 9r are a pair of wheels that are relatively located at the rear of the four wheels of the vehicle 100. The rear of the vehicle 100 refers to the direction opposite to the front of the vehicle 100. The rear drive system rds causes the rear wheels 9r to act as drive wheels 9 that generate the driving force of the vehicle 100.

[0019] The battery 1 is connected to the motor 4 via the inverter 3 and supplies drive power to the motor 4 by discharging. In addition, the battery 1 can receive the supply of regenerative power from the motor 4 and be charged. In the front drive system fds, the battery 1 is connected to the front drive motor 4f via the front inverter 3f. Similarly, in the rear drive system rds, the battery 1 is connected to the rear drive motor 4r via the rear inverter 3r.

[0020] The controller 2 is a control device for the vehicle 100 and is a computer composed of a central processing unit (CPU), a read-only memory (ROM), a random access memory (RAM), an input / output interface (I / O interface), etc. The controller 2 generates control signals for controlling the front drive motor 4f and the rear drive motor 4r based on the vehicle variables of the vehicle 100. The vehicle variables refer to information on the operating state or control state of the whole vehicle 100 or each part constituting the vehicle 100, and can be obtained through detection, measurement, calculation, etc. For example, in addition to the accelerator opening APO, longitudinal G and lateral G, vehicle speed V, gradient value, steering angle, and wheel speed described later, the vehicle variables also include the rotational speeds Nmf, Nmr of the respective motors 4f, 4r, three-phase alternating current, etc. The controller 2 controls the front drive motor 4f and the rear drive motor 4r respectively using the above vehicle variables.

[0021] The front inverter 3f and the rear inverter 3r turn on / off the switching elements according to the drive signals generated by the controller 2, thereby converting the direct current supplied from the battery 1 into alternating current and adjusting the current supplied to the front drive motor 4f and the rear drive motor 4r respectively. In addition, each inverter 3f, 3r inversely converts the alternating current generated by the front drive motor 4f and the rear drive motor 4r into direct current using the regenerative braking force and adjusts the current supplied to the battery 1.

[0022] The front drive motor 4f and the rear drive motor 4r are, for example, three-phase AC motors, and generate a driving force (torque T) using the alternating current supplied from the connected inverter 3. The driving force generated by the front drive motor 4f is transmitted to the front wheels 9f via the front speed reducer 5f and the front drive shaft 8f. Similarly, the driving force generated by the rear drive motor 4r is transmitted to the rear wheels 9r via the rear speed reducer 5r and the rear drive shaft 8r. The front drive motor 4f and the rear drive motor 4r generate a regenerative braking force when rotated by the front wheels 9f and the rear wheels 9r respectively, and recover the kinetic energy of the vehicle 100 as electric energy. The front drive motor 4f constitutes a drive source (front drive source) for driving the front wheels 9f. Similarly, the rear drive motor 4r constitutes a drive source (rear drive source) for driving the rear wheels 9r independently of the front wheels 9f.

[0023] The front speed reducer 5f and the rear speed reducer 5r are composed of, for example, a plurality of gears. Each of the above speed reducers 5f, 5r reduces the rotational speed Nm of the connected motor 4 and transmits it to the drive shaft 8, thereby generating a drive torque or a braking torque proportional to the reduction ratio. The front rotation sensor 6f and the rear rotation sensor 6r detect the rotor phase of the connected motor 4 and output it to the controller 2. Regarding the controller 2, the rotational speed Nmf of the front drive motor 4f is detected based on the output of the front rotation sensor 6f, and the rotational speed Nmr of the rear drive motor 4r is detected based on the output of the rear rotation sensor 6r. The front current sensor 7f and the rear current sensor 7r detect the current flowing in the connected motor 4 and output it to the controller 2. In the present embodiment, the current sensors 7f, 7r detect the three-phase alternating current of the respective motors 4f, 4r.

[0024] In addition to the above front rotation sensor 6f, front current sensor 7f, rear rotation sensor 6r, and rear current sensor 7r, the vehicle 100 also has various sensors 15. The various sensors 15 include, for example, an accelerator opening sensor 15a, an acceleration sensor 15b, a vehicle speed sensor 15c, as well as a slope sensor, a steering angle sensor, a wheel speed sensor, etc. The accelerator opening sensor 15a detects the accelerator opening APO as the accelerator operation amount. The acceleration sensor 15b detects the acceleration of the vehicle 100 in the front-rear direction and the lateral direction, that is, the longitudinal G and the lateral G. The vehicle speed sensor 15c detects the vehicle speed V of the vehicle 100. The vehicle speed V is the moving speed of the entire vehicle body of the vehicle 100, that is, the body speed. The slope sensor detects the slope value as the driving road slope of the vehicle 100. The steering angle sensor detects the steering angle of the steering wheel. The wheel speed sensor detects the wheel speed of each drive wheel 9. The detection values detected by the various sensors 15 are input to the controller 2.

[0025] In the vehicle 100, the requested torque of the driver, i.e., the target driving torque T_req, is distributed to the front wheels 9f and the rear wheels 9r. Therefore, if either the torque distribution value RT for the front wheels 9f, i.e., the front torque distribution value RTf, or the torque distribution value RT for the rear wheels 9r, i.e., the rear torque distribution value RTr, is determined, the other is also determined. As a result, the torque distribution between the front and rear wheels 9f, 9r is also determined. Thus, in the vehicle 100, as described later, the torque T of the rear drive motor 4r, i.e., the rear torque Tr, is calculated based on the operating state represented by the first parameters such as the front and rear G. Thereby, the rear torque distribution value RTr becomes a state where it can be calculated, and substantially the rear torque distribution value RTr is calculated to perform torque distribution control for the front and rear wheels 9f, 9r.

[0026] [Structure of the control system]

[0027] Figure 2 is a block diagram of the control system of the electric vehicle according to the present embodiment. Figure 3 is a graph showing the relationship between the temperature of the battery 1 and the input / output characteristics of the battery 1. Figure 4 is a graph showing the relationship between the state of charge (SOC) of the battery 1 and the input characteristics of the battery 1.

[0028] The control system of the electric vehicle according to the present embodiment includes a navigation device 20, an EV controller 21, a battery controller 22, a charging controller 23, and a charger 24.

[0029] The navigation device 20 generates map information including information on the driving route from the current location (or departure location) of the vehicle 100 to the destination (or via point), and outputs it to the EV controller 21. Information on the current location (departure location) of the vehicle 100 is obtained, for example, by GPS (Global Positioning System) and obtained by matching it to the roads on the map information possessed by the navigation device 20. Information on the destination is obtained by determining the destination on the map information through the input operation of the driver. Here, the destination is, for example, the final location of the navigation and the position where the entire vehicle system stops. Information on the driving route is obtained by the navigation device 20 selecting a route connecting the current location (departure location) and the destination in the map information. The map information (information on the driving route) includes information on the distance to the destination, information on the positions of the roads constituting the driving route, information on the gradients of the roads, information on the elevation differences, information on charging stations (locations, charger outputs), etc. In addition, the map information includes information on the roads (adjacent) facing the charging stations, and this road information includes information on attributes (ordinary roads, highways), predicted vehicle speeds (statutory speed limits, statistical average vehicle speeds), information on the gradients of the roads, etc.

[0030] The charger 24 is arranged at a service area on an expressway or a parking lot facing a general road, etc. If the driver inserts the charging plug of the charger 24 into the charging inlet arranged on the vehicle 100, the battery 1 can be charged.

[0031] The charging controller 23 is electrically connected to the said inlet. Thus, if the charging controller 23 inserts the charging plug into the said inlet, the charging plug is detected and output as a detection signal to the battery controller 22.

[0032] In addition, the charging controller 23 outputs the allowable charging signal input from the EV controller 21 as a request charging signal to the charger 24. Here, the allowable charging signal (request charging signal) is a signal for setting the charging power (input) supplied from the charger 24 to the battery 1. The charger 24 outputs charging power to the battery 1 based on the request charging signal input from the charging controller 23.

[0033] The battery controller 22 includes the said front inverter 3f and rear inverter 3r, and controls the supply and reception of power between the battery 1 and the motor 4. If the battery controller 22 receives a drive signal input from the EV controller 21, it extracts drive power corresponding to the drive signal from the battery 1 and outputs it to the motor 4. If the battery controller 22 receives a regeneration signal input from the EV controller 21, it extracts regeneration power corresponding to the regeneration signal from the motor 4 and supplies it to the battery 1.

[0034] If the battery controller 22 receives a detection signal input from the charging controller 23, it outputs information on the temperature of the battery 1 and the state of charge (SOC) of the battery 1 to the EV controller 21.

[0035] The battery controller 22 monitors the temperature of the battery 1. Regarding the battery controller 22, when a driving mode (high-load driving) described later is input from the EV controller 21, if the temperature of the battery 1 is higher than the first upper limit temperature (T max1 , a temperature lower than the heat-resistant temperature), the allowable charge and discharge power [kW] of the battery 1 is restricted, and an allowable charge and discharge signal reflecting this allowable charge and discharge power is output to the EV controller 21. Here, the heat-resistant temperature refers to the upper limit temperature at which the battery 1 can operate without irreversible thermal damage.

[0036] Regarding the battery controller 22, when a driving mode (low-load driving) described later is input from the EV controller 21, if the temperature of the battery 1 is higher than the second upper limit temperature (T max2 , a temperature lower than the heat-resistant temperature), the allowable charge and discharge power [kW] of the battery 1 is restricted, and an allowable charge and discharge signal reflecting this allowable charge and discharge power is output to the EV controller 21.

[0037] Regarding the battery controller 22, if the temperature of battery 1 is lower than the lower limit temperature (T min , the lower limit temperature at which a decrease in the charge and discharge capacity of battery 1 does not occur), the allowable charge and discharge power of battery 1 is restricted, and an allowable charge and discharge signal reflecting this allowable charge and discharge power is output to the EV controller 21.

[0038] In addition, in Figure 3 , the magnitude of the allowable charge and discharge power (allowable input / output) between the second upper limit temperature (T max2 ) and the lower limit temperature (T min ) corresponds to the output of battery 1 during high-load driving described later. In addition, in Figure 3 , the input characteristics and output characteristics of battery 1 are the same, but they may also have different characteristics.

[0039] The battery controller 22 monitors the state of charge (SOC) of battery 1. As Figure 4 shown, if the state of charge (SOC) of battery 1 is higher than a specified upper limit value (S max : for example, 90 [%]), the allowable charge and discharge power [kW] of battery 1 is restricted, and an allowable charge and discharge signal reflecting this allowable charge and discharge power is output to the EV controller 21.

[0040] The EV controller 21 includes the said controller 2. Regarding the EV controller 21, map information including information on the driving route from the current location (or the starting location) to the destination is input from the navigation device 20, and the driving mode (low-load driving, high-load driving) of the vehicle 100 starting from the charging station is predicted based on the map information, and the information on the driving mode is output to the battery controller 22.

[0041] Low-load driving refers to a driving state in which the acceleration of the vehicle 100 at the start is low and lower than the speed when driving at a substantially constant speed (for example, less than 80 [km / s] per hour).

[0042] The charging station is, for example, in a parking lot facing a general road. When the destination is close to this parking lot (for example, 2 - 3 [km]), it is predicted that the accelerator pedal depression amount of the driver on the general road is small, that is, the acceleration and speed are also low, and the vehicle arrives at the destination in a state where the load on battery 1 is also small. This situation is predicted as low-load driving. In addition, when the vehicle 100 starts to drive on the general road, there is acceleration, but if the vehicle speed becomes substantially constant, the acceleration is approximately zero. Therefore, it can be predicted that low-acceleration starting occurs in the initial stage of low-load driving.

[0043] In addition, even when the destination is far from the charging station and the speed limit on the general road facing the charging station is set low, it can be predicted that the driver will drive the vehicle 100 at a low load and start with a low acceleration.

[0044] High-load driving (high-speed driving) refers to a driving state in which, for example, the acceleration when the vehicle 100 starts is high and the speed when it travels at a substantially constant speed is also high (for example, greater than or equal to 80 [km / s] per hour).

[0045] When the charging station is configured in a service area on a highway, after the battery 1 is charged, the driver merges onto the highway, so it is predicted that the accelerator pedal will be depressed more and the vehicle will reach high-speed operation before merging onto the highway. In this case, the acceleration and speed are high, and the load on the battery 1 is also large. This situation is predicted as high-load driving. In addition, the acceleration remains high at least until merging onto the highway. Therefore, it can be predicted that rapid acceleration starting will occur in the initial stage of low-load driving, that is, from the charging station in the service area to the merging point on the highway.

[0046] In addition, when the road facing the charging station has a specified uphill slope and is continuous for a specified distance (for example, 1 kilometer), the accelerator pedal is depressed more and a high torque is requested for the motor 4. At this time, the EV controller 21 determines that a high load is requested for the battery 1, and predicts high-load driving (high-torque driving) as the driving mode on this road.

[0047] As described above, the EV controller 21 estimates information on low-load driving (information on low-acceleration starting) and high-load driving (information on rapid acceleration starting) based on the map information, and stores the above-mentioned past information.

[0048] Therefore, the EV controller 21 determines whether there is past information (map information including the same information) on the current map information (information on the predicted vehicle speed of the road facing the charging station, etc.) input from the navigation device 20. If there is past information, the information on low-load driving (information on low-acceleration starting) and high-load driving (information on rapid acceleration starting) associated with the past information can be extracted and the control described below can be executed. Thereby, the processing burden on the EV controller 21 can be reduced.

[0049] The EV controller 21 can be configured as follows. That is, compared with the current map information, it extracts the past map information common to the predicted vehicle speed information of the road leading to the charging station, compares the number of pieces of information on low-load driving (low-acceleration start) and the number of pieces of information on high-load driving (rapid-acceleration start) included in the past map information, and sets the one with the larger number of pieces of information as the driving mode. Thereby, control reflecting the driver's driving style can be performed.

[0050] However, it is known that the driving path from the current location (or departure location) of the vehicle 100 to the destination is a monotonous terrain, and sometimes it is known that the load (input / output) on the battery 1 is substantially constant. In this case, it is also preferable that the EV controller 21 predicts either low-load driving (low-acceleration start) or high-load driving (rapid-acceleration start) as the driving mode based on the average value of the load on the battery 1 from the departure location to the charging station. Thereby, the processing burden on the EV controller 21 can be reduced.

[0051] The EV controller 21 generates an allowable charging signal based on the information on the temperature of the battery 1 and the state of charge (SOC) of the battery 1 and outputs it to the charging controller 43.

[0052] At this time, when the battery 1 of the vehicle 100 is being charged and the driving mode is predicted to be high-load driving (high-acceleration start), the EV controller 21 sets the upper limit value of the allowable charging power related to the allowable charging signal based on the allowable charge and discharge signal (a signal that limits the allowable charge and discharge power at a value greater than or equal to the first upper limit temperature (T max1 ) input from the battery controller 22).

[0053] In addition, when the battery 1 of the vehicle 100 is being charged and the driving mode is predicted to be low-load driving (low-acceleration start), the EV controller 21 sets the upper limit value of the allowable charging power related to the allowable charging signal based on the allowable charge and discharge signal (a signal that limits the allowable charge and discharge power at a value greater than or equal to the second upper limit temperature (T max2 ) input from the battery controller 22).

[0054] [Control Flow]

[0055] Figure 5 It is a flowchart of the control system of the electric vehicle of the present embodiment.

[0056] As an initial state, the vehicle 100 arrives at the charging station, the charging plug of the charger 24 is inserted into the charging inlet of the vehicle 100, and the battery controller 22 receives the detection signal and sends the information on the temperature of the battery 1 and the state of charge (SOC) of the battery 1 to the EV controller 21.

[0057] In step S101, the EV controller 21 outputs a charging permission signal to the charging controller 23. Thereby, the charging controller 23 outputs a power generation request signal to the charger 24, and the charger 24 supplies charging power to the battery 1 based on the request charging signal (charging permission signal) to start charging the battery 1.

[0058] In step S102, the EV controller 21 predicts the driving pattern of the vehicle 100 when driving from the charging station according to the map information including the information of the road from the navigation device 20 to the charging station (information of predicted vehicle speed, information of slope).

[0059] In step S103, the EV controller 21 determines whether the driving pattern is low-load driving (low-acceleration start). If YES, it proceeds to step S104. If NO, the driving pattern is high-load driving (quick-acceleration start) and it proceeds to step S112.

[0060] In step S104, the EV controller 21 sets the upper limit temperature during charging of the battery 1 to the second upper limit temperature (T max2 ).

[0061] In step S105, the EV controller 21 determines whether the charging rate of the battery 1 has reached a specified value (e.g., 50 [%]). If YES, it proceeds to step S106. If NO, it proceeds to step S107.

[0062] In step S106, the EV controller 21 (battery controller 22) restricts the input (charging power) of the battery 1 according to the Figure 4 corresponding graph.

[0063] In step S107, the EV controller 21 determines whether the temperature of the battery 1 has reached the second upper limit temperature (T max2 ). If YES, it proceeds to step S108. If NO, it proceeds to step S109.

[0064] In step S108, the EV controller 21 restricts the input (charging power) of the battery 1 according to the Figure 3 corresponding graph. In addition, when the input (charging power) of the battery 1 is restricted in step S106 (or step S113), the input (charging power) of the battery 1 is further restricted in step S108.

[0065] In step S109, it is determined whether the battery 1 is fully charged. If YES, it proceeds to step S110. If NO, it stays at step S109. Here, being fully charged means that the charging rate of the battery 1 reaches a specified upper limit value (e.g., 90 [%]) or a specified time has elapsed since the start of charging.

[0066] In step S110, the EV controller 21 stops the input (charging) of the battery 1.

[0067] In step S111, the EV controller 21 sets the upper limit temperature during charging of the battery 1 to the first upper limit temperature (T max1 ).

[0068] In step S112, the EV controller 21 determines whether the charging rate of the battery 1 has reached a specified value (e.g., 50 [%]). If YES, it proceeds to step S113; if NO, it proceeds to step S114.

[0069] In step S113, the EV controller 21 (battery controller 22) restricts the input (charging power) of the battery 1 according to Figure 4 the corresponding graph.

[0070] In step S114, the EV controller 21 determines whether the temperature of the battery 1 has reached the first upper limit temperature (T max1 ). If YES, it proceeds to step S108; if NO, it proceeds to step S109.

[0071] [First timing diagram]

[0072] Figure 6 It is a timing diagram when it is predicted that the vehicle 100 will travel by high-load driving (rapid acceleration start) after charging the battery 1 in the control system of the electric vehicle according to the present embodiment. In Figure 6 , when it is predicted that the vehicle 100 will travel by high-load driving (rapid acceleration start) after charging, the timing diagram (solid line) when the upper limit temperature of the charging battery 1 is set to the first upper limit temperature (T max1 )( Figure 5 step S111) and the timing diagram (dashed line) when the upper limit temperature of the charging battery 1 is set to the second upper limit temperature (T max2 ) are compared.

[0073] At time t0, if the EV controller 21 (battery controller 22) starts charging the battery 1, the input (charging power), the temperature, and the charging rate (SOC) of the battery 1 increase. In addition, the EV controller 21 predicts whether the driving mode of the vehicle 100 after charging the battery 1 is high-load driving (rapid acceleration start) based on information such as the road leading to the charging station.

[0074] At time t1, if the charging rate of the battery 1 reaches the specified value S1 (e.g., 50 [%]), the input to the battery 1 is restricted. As a result, after time t1, the rising speed (slope) of the temperature of the battery 1 and the rising speed (slope) of the charging rate of the battery 1 decrease.

[0075] When the upper limit temperature of the battery 1 being charged is set to the first upper limit temperature (T min1 ), at time t2, if the temperature of the battery 1 reaches the first upper limit temperature (T max1 ), then based on Figure 3 the corresponding graph (solid line) shown, the input (charging power) of the battery 1 is restricted. Thus, after time t1, the input (solid line) of the battery 1 further decreases, and the rising speed (slope) of the charging rate (solid line) of the battery 1 also further decreases.

[0076] At time t4, the battery 1 is fully charged and the charging of the battery 1 is completed, and the vehicle 100 travels by high-load driving (rapid acceleration start). At this time, the temperature of the battery 1 is the first upper limit temperature (T max2 ) which is lower than the second upper limit temperature (T max1 ), and the input and output of the battery 1 are not restricted by temperature, and the battery 1 can achieve the output (solid line) and vehicle speed (solid line) requested by the driver.

[0077] On the other hand, when the upper limit temperature of the battery 1 being charged is set to the second upper limit temperature (T max2 ), the restriction of the input of the battery 1 is not performed at time t2. After time t2, at time t3, the temperature of the battery 1 reaches the second upper limit temperature (T max2 ) and based on Figure 3 the corresponding graph (dashed line) shown, the input (charging power) of the battery 1 is restricted. Thus, after time t3, the input (dashed line) of the battery 1 decreases, and the rising speed (slope) of the charging rate (dashed line) of the battery 1 also decreases.

[0078] At time t4, the charging of the battery 1 is completed, and the vehicle 100 travels by high-load driving (rapid acceleration start). At this time, the temperature of the battery 1 reaches the second upper limit temperature (T max2 ). Therefore, after time t5, according to Figure 3 the corresponding graph (dashed line), the output (dashed line) of the battery 1 is restricted, and the battery 1 cannot achieve the output (solid line) requested by the driver, and thus it becomes a state where the vehicle speed (dashed line) is also lower than the vehicle speed (solid line).

[0079] [Second Timing Diagram]

[0080] Figure 7 is a timing diagram regarding the control system of the electric vehicle according to the present embodiment when it is predicted that after the battery 1 is charged, the vehicle 100 travels by low-load driving (low-acceleration start).

[0081] At Figure 7In the case where, after being predicted to be charged, the vehicle 100 travels by low-load driving (low-acceleration start), when setting the upper limit temperature of the battery 1 being charged to the second upper limit temperature (T max2 )( Figure 5 in step S104), compare the timing diagram (solid line) when setting the upper limit temperature of the battery 1 being charged to the first upper limit temperature (T max1 ) with the timing diagram (dashed line).

[0082] At time t0, if the EV controller 21 (battery controller 22) starts charging the battery 1, the input to the battery 1, the temperature of the battery 1, and the charge rate (SOC) of the battery 1 increase. In addition, the EV controller 21 predicts, based on information such as the road leading to the charging station, that the driving mode of the vehicle 100 after charging the battery 1 will be low-load driving (low-acceleration start).

[0083] At time t1, if the charge rate of the battery 1 reaches a specified value S1 (e.g., 50 [%]), the input to the battery 1 is restricted. As a result, after time t1, the rate of increase (slope) of the temperature of the battery 1 and the rate of increase (slope) of the charge rate of the battery 1 decrease.

[0084] In the case where the upper limit temperature of the battery 1 during charging is set to the first upper limit temperature (T max1 ), at time t2, if the temperature of the battery 1 reaches the first upper limit temperature (T max1 ), then based on Figure 3 the corresponding diagram (solid line) shown, restrict the input (charging power) to the battery 1. As a result, after time t2, the input to the battery 1 (dashed line) further decreases, and the rate of increase (slope) of the charge rate of the battery 1 (dashed line) also further decreases.

[0085] At time t4, the SOC of the battery 1 reaches the charge rate when fully charged, and the charging of the battery 1 is completed. The vehicle 100 travels by low-load driving (low-acceleration start). However, since the load on the battery 1 is low, the temperature of the battery 1 does not increase thereafter but monotonically decreases. Here, there is a correlation between the temperature of the battery 1 during charging and the charge rate of the battery 1. Therefore, for the vehicle 100 predicted to travel at low load, if the upper limit temperature during charging of the battery 1 is set to the first upper limit temperature (T max2 ) lower than the second upper limit temperature (T max1 ), it will be fully charged at a lower charge rate compared to the charge rate expected by the driver, which will cause discomfort to the driver.

[0086] On the other hand, when setting the upper limit temperature of the battery 1 during charging to the second upper limit temperature (T max2)In the case of (), after time t2, at time t3, if the temperature of battery 1 reaches the second upper limit temperature (T max2 ), then based on Figure 3 the corresponding graph (dotted line) to limit the input (charging power) of battery 1. Thus, after time t3, the input of battery 1 (solid line) further decreases, and the rising speed (slope) of the charging rate (solid line) of battery 1 also further decreases.

[0087] Moreover, the charging of battery 1 is completed at time t4, but the charging rate (solid line) at this time becomes higher than the value of the charging rate (dotted line) obtained by setting the upper limit voltage during charging of battery 1 to the first upper limit voltage (T max1 ), and the charging rate expected by the driver can be ensured.

[0088] [Effects of this Embodiment]

[0089] According to the control method of the electric vehicle of this embodiment, power is supplied and received between the drive motor (motor 4) and battery 1, and when the temperature of battery 1 during the vehicle 100 is running exceeds the specified first upper limit temperature (T max1 ), the charge and discharge power of battery 1 is restricted. Among them, according to the information of the road leading to the charging station for charging battery 1, it is predicted that the vehicle 100 will travel from the charging station in any driving mode, either low-load driving in a state where the load on battery 1 is low or high-load driving in a state where the load is higher than the low load. When it is predicted that the driving mode is high-load driving, the upper limit temperature of battery 1 during charging is set to the first upper limit temperature (T max1 ), and when it is predicted that the driving mode is low-load driving, the upper limit temperature of battery 1 during charging is set to a temperature higher than the first upper limit temperature (T max1 ) and lower than the heat-resistant temperature of battery 1, which is the second upper limit temperature (T max2 ).

[0090] According to the above method, when the driving mode after charging of battery 1 is high-load driving, the upper limit temperature during charging of battery 1 is set to the first upper limit temperature (T max1 ), so that the output expected by the driver can be achieved after charging of battery 1. In addition, when the driving mode after charging of battery 1 is low-load driving, the upper limit temperature during charging of battery 1 is set to the second upper limit temperature (T max2 ), so that the charging rate (SOC) of battery 1 expected by the driver can be obtained after charging.

[0091] In the present embodiment, information on low-load driving, information on high-load driving, and information on charging stations are estimated based on map information representing roads.

[0092] According to the above method, information on low-load driving, information on high-load driving, and information on charging stations can be easily estimated based on map information.

[0093] In the present embodiment, information on charging stations is estimated based on map information representing roads, and past information on low-load driving or high-load driving calculated using past map information identical to the map information and the information on charging stations is set as the driving mode.

[0094] According to the above method, charging stations can be easily and highly accurately estimated, and information on low-load driving or high-load driving of past information is extracted and set as the driving mode, so that the processing load (of the EV controller 21) can be reduced.

[0095] In the present embodiment, information on low-load driving and information on high-load driving are estimated based on the load from the departure point of the vehicle 100 to the charging station.

[0096] According to the above method, in the case where the states of the roads from the departure point of the vehicle 100 to the road facing the charging station and the road of the charging station are monotonous and known, low-load driving and high-load driving can be easily estimated without using map information.

[0097] In the present embodiment, information on charging stations is estimated based on map information representing roads. The map information includes information on the predicted vehicle speed of the road facing the charging station. Past map information with common information on the predicted vehicle speed of the road is extracted, and the number of pieces of information on low-load driving and the number of pieces of information on high-load driving included in the past map information are compared, and the one with the larger number of pieces of information is set as the driving mode.

[0098] According to the above method, the driving mode can be set in accordance with the driving style of the driver.

[0099] In the present embodiment, information on charging stations is estimated based on map information representing roads. The map information includes information on the predicted vehicle speed of the road. In the case where the predicted vehicle speed of the road is greater than or equal to a specified speed, high-load driving is predicted as the driving mode.

[0100] According to the above method, high-load driving can be highly accurately predicted as the driving mode based on map information.

[0101] In the present embodiment, information on a charging station is estimated based on map information representing a road, and the map information includes information on the slope of the road facing the charging station. In the map information, when the road facing the charging station has a prescribed uphill slope and the road is continuous for a prescribed distance, high-load driving is predicted as a driving pattern.

[0102] According to the above method, high-load driving can be predicted with high accuracy as a driving pattern based on map information.

[0103] In the present embodiment, after the vehicle 100 departs from the charging station, when the vehicle accelerates within a short period of time and travels at substantially a constant speed, the information on low-load driving includes information indicating a low-acceleration start in which the vehicle 100 starts at a low speed when starting to travel from the charging station, and the information on high-load driving includes information indicating a rapid-acceleration start in which the vehicle 100 starts with rapid acceleration when starting to travel from the charging station. As a driving pattern, either a low-acceleration start or a rapid-acceleration start is selected. When the predicted driving pattern is a rapid-acceleration start, the upper limit temperature of the battery 1 during charging of the battery 1 is set to a first upper limit temperature (T max1 ), and when the predicted driving pattern is a low-acceleration start, the upper limit temperature of the battery 1 during charging of the battery 1 is set to a second upper limit temperature (T max2 ).

[0104] According to the above method, when the driving pattern after charging of the battery 1 is a rapid-acceleration start, the upper limit temperature during charging of the battery 1 is set to the first upper limit temperature (T max1 ), whereby the battery 1 can achieve the output expected by the driver after charging. In addition, when the driving pattern after charging of the battery 1 is a low-acceleration start, the upper limit temperature during charging of the battery 1 is set to the second upper limit temperature (T max2 ), whereby the charging rate of the battery 1 when fully charged, which is expected by the driver, can be obtained.

[0105] In the present embodiment, information on a charging station is estimated based on map information representing a road, and the information on a previous low-acceleration start or rapid-acceleration start calculated using the same previous map information as the map information and the information on the charging station is set as the driving pattern.

[0106] According to the above method, the charging station can be estimated simply and with high accuracy, and the information on a previous low-acceleration start or rapid-acceleration start is extracted and set as the driving pattern, so that the processing load (of the EV controller 21) can be reduced.

[0107] In the present embodiment, the information on a low-acceleration start and the information on a rapid-acceleration start are estimated based on the load from the departure point of the vehicle 100 to the charging station.

[0108] According to the above method, when the states of the road from the departure location of the vehicle 100 to the charging station and the road of the charging station are monotonous, it is possible to simply estimate the information of a low-acceleration start and a rapid-acceleration start without using map information.

[0109] In the present embodiment, the information of the charging station is estimated based on the map information indicating the road. The map information includes the information of the predicted vehicle speed of the road facing the charging station. The past map information common to the information of the predicted vehicle speed of the road is extracted, and the number of low-acceleration start information and the number of rapid-acceleration start information included in the past map information are compared, and the one with the larger number of information is set as the driving mode.

[0110] According to the above method, it is possible to set the driving mode in accordance with the driving style of the driver.

[0111] In the present embodiment, the information of the charging station is estimated based on the map information indicating the road. The map information includes the information of the predicted vehicle speed of the road. In the map information, when the predicted vehicle speed is greater than or equal to a specified speed, a rapid-acceleration start is predicted as the driving mode.

[0112] According to the above method, it is possible to accurately predict a rapid-acceleration start as the driving mode based on the map information.

[0113] The control system of the electric vehicle according to the present embodiment includes: a drive motor (motor 4); a battery 1 that supplies and receives power to and from the drive motor (motor 4); and a control unit (EV controller 21) that restricts the charge and discharge power (input / output) of the battery 1 when the temperature of the battery 1 exceeds a specified first upper limit temperature (T max1 ). Among them, the control unit (EV controller 21) predicts which driving mode the vehicle 100 will drive from the charging station through low-load driving in which the vehicle 100 travels in a state where the load on the battery 1 is low or high-load driving in which the vehicle 100 travels in a state where the load is higher than the low load based on the information of the road facing the charging station for charging the battery 1. When it is predicted that the driving mode is high-load driving, the upper limit temperature of the battery 1 during charging of the battery 1 is set as the first upper limit temperature (T max1 ). When it is predicted that the driving mode is low-load driving, the upper limit temperature of the battery 1 during charging of the battery 1 is set as a temperature higher than the first upper limit temperature (Tm max1 ) and lower than the heat-resistant temperature of the battery 1, which is the second upper limit temperature (T max2 ).

[0114] According to the above structure, when the driving mode after charging the battery 1 is high-load driving, the upper limit temperature during charging of the battery 1 is set to the first upper limit temperature (T max1 ), thereby enabling the battery 1 to achieve the output expected by the driver after charging. When the driving mode after charging the battery 1 is low-load driving, the upper limit temperature during charging of the battery 1 is set to the second upper limit temperature (T max2 ), thereby enabling the charging rate when the battery 1 is fully charged as expected by the driver to be obtained.

[0115] The embodiments of the present invention have been described above, but the above embodiments only show a part of the application examples of the present invention, and the gist is not to limit the technical scope of the present invention to the specific structures of the above embodiments. In addition, the above embodiments can be combined appropriately.

Claims

1. A control method for an electric vehicle that supplies and receives electric power between a drive motor and a battery, and limits the charge and discharge power of the battery when the temperature of the battery exceeds a specified first upper limit temperature, wherein, Based on information about the road leading to the charging station for charging the battery, predict which driving mode the vehicle will use to drive, i.e., low-load driving in which the vehicle travels in a state of low load on the battery or high-load driving in which the vehicle travels in a state of high load greater than the low load, and drive from the charging station. When the driving mode is predicted to be the high-load driving, set the upper limit temperature of the battery during charging of the battery to the first upper limit temperature. When the driving mode is predicted to be the low-load driving, set the upper limit temperature of the battery during charging of the battery to a second upper limit temperature that is higher than the first upper limit temperature and lower than the heat-resistant temperature of the battery.

2. The control method for an electric vehicle according to claim 1, wherein, Estimate the information on low-load driving, the information on high-load driving, and the information on the charging station based on the map information representing the road.

3. The control method for an electric vehicle according to claim 1, wherein, Estimate the information on the charging station based on the map information representing the road. Set the information on the previous low-load driving or the previous high-load driving calculated using the same previous map information as the map information and the information on the charging station as the driving mode.

4. The control method for an electric vehicle according to claim 1, wherein, Estimate the information on low-load driving and the information on high-load driving based on the load from the departure location of the vehicle to the charging station.

5. The control method for an electric vehicle according to claim 1, wherein, Estimate the information on the charging station based on the map information representing the road. The map information includes information on the predicted vehicle speed of the road leading to the charging station. Extract the previous map information common to the information on the predicted vehicle speed of the road, compare the number of information on low-load driving and the number of information on high-load driving included in the previous map information, and set the one with the larger number of information as the driving mode.

6. The control method for an electric vehicle according to claim 1, wherein, Estimate the information on the charging station based on the map information representing the road. The map information includes information on the predicted vehicle speed of the road. When the predicted vehicle speed of the road is greater than or equal to a specified speed, predict the high-load driving as the driving mode.

7. The control method for an electric vehicle according to claim 1, wherein, Estimate the information on the charging station based on the map information representing the road. The map information includes information on the slope of the road leading to the charging station. When the road facing the charging station in the map information has a prescribed uphill slope and the road is continuous for a prescribed distance, the high-load driving is predicted as the driving mode.

8. The control method for an electric vehicle according to claim 1, wherein when the vehicle accelerates within a short time after departing from the charging station and travels at a substantially constant speed, the information on the low-load driving includes information indicating a low-acceleration start in which the vehicle starts at a low speed when starting to drive from the charging station, the information on the high-load driving includes information indicating a rapid-acceleration start in which the vehicle starts by rapidly accelerating when starting to drive from the charging station, either the low-acceleration start or the rapid-acceleration start is selected as the driving mode, when the driving mode is predicted to be the rapid-acceleration start, the upper limit temperature of the battery during battery charging is set to the first upper limit temperature, when the driving mode is predicted to be the low-acceleration start, the upper limit temperature of the battery during battery charging is set to the second upper limit temperature.

9. The control method for an electric vehicle according to claim 8, wherein the information on the charging station is estimated based on the map information indicating the road, the information on the previous low-acceleration start or the rapid-acceleration start calculated using the same previous map information as the map information and the information on the charging station is set as the driving mode.

10. The control method for an electric vehicle according to claim 8, wherein the information on the low-acceleration start and the rapid-acceleration start is estimated based on the load from the departure location of the vehicle to the charging station.

11. The control method for an electric vehicle according to claim 8, wherein the information on the charging station is estimated based on the map information indicating the road, the map information includes information on the predicted vehicle speed of the road facing the charging station, the previous map information common to the information on the predicted vehicle speed of the road is extracted, the number of information on the low-acceleration start and the number of information on the rapid-acceleration start included in the previous map information are compared, and the one with the larger number of information is set as the driving mode.

12. The control method for an electric vehicle according to claim 8, wherein the information on the charging station is estimated based on the map information indicating the road, the map information includes information on the predicted vehicle speed of the road, when the predicted vehicle speed in the map information is greater than or equal to a prescribed speed, the rapid-acceleration start is predicted as the driving mode.

13. A control system for an electric vehicle, comprising: a drive motor; a battery that supplies and receives electric power to and from the drive motor; and a control unit that restricts the charge and discharge power of the battery when the temperature of the battery exceeds a prescribed first upper limit temperature, wherein The control unit predicts which driving mode, i.e., low-load driving in which the vehicle travels in a state where the load on the battery is low or high-load driving in which the vehicle travels in a state where the load is higher than the low load, the vehicle will pass through the charging station based on information about the road leading to the charging station for charging the battery, and then travels from the charging station. When the driving mode is predicted to be the high-load driving, the upper limit temperature of the battery during charging of the battery is set to the first upper limit temperature. When the driving mode is predicted to be the low-load driving, the upper limit temperature of the battery during charging of the battery is set to a temperature higher than the first upper limit temperature and lower than the heat-resistant temperature of the battery, which is the second upper limit temperature.

Images