CHARGING CONTROL SYSTEM

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to Japanese Patent Application No. 2022-016698 filed on Feb. 4, 2022, the contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a charging control system mounted on a vehicle.

BACKGROUND ART

In recent years, as a specific measure against climate change of the earth, efforts to realize a low-carbon society or a decarbonized society have been actively made. In vehicles, a reduction in CO2 emission and an improvement in energy efficiency are strongly required, and a driving source is rapidly electrified. Specifically, a vehicle such as an electrical vehicle or a hybrid electrical vehicle has been developed which includes an electric motor as the driving source of the vehicle, and a battery as a secondary battery capable of supplying electric power to the electric motor.

In such a vehicle, normal charging in which a battery is charged by being connected to an external power supply or rapid charging in which a current larger than that in the normal charging flows through the battery to charge the battery can be performed. Since the battery generates heat at the time of charging and discharging, it is necessary to appropriately cool the battery. In particular, the battery is likely to generate heat at the time of the rapid charging. When the battery generates heat and reaches a temperature equal to or higher than a predetermined temperature, a charging output of the battery is restricted from the viewpoint of safety (for example, JP2021-48737A).

In a general charging control, the battery is cooled so as not to reach a temperature equal to or higher than the predetermined temperature based on a cooling capacity of a cooling system, and a time until the battery reaches a target SOC is controlled so as to be shortest.

However, when two or more times of charging are scheduled in one scheduled travel plan, an amount of heat accumulated in the battery by a first charging affects a second and subsequent charging, and the charging output may be restricted in the second and subsequent charging. That is, although the charging output can be increased by using a heat capacity (thermal mass) of the battery at the time of the first charging, a temperature of the battery tends to become high at the time of the second and subsequent charging because the heat capacity (thermal mass) of the battery is already used. If the charging output is restricted, an arrival at a destination is naturally delayed.

An object of the present invention is to provide a vehicle capable of shortening a destination arrival time by optimizing charging.

SUMMARY OF INVENTION

According to an aspect of the present invention, there is provided a charging control system including:

a battery rechargeable with electric power from an external power supply;

a battery temperature control device that adjusts a temperature of the battery; and

a controller that controls the battery and the battery temperature control device, in which

the controller includes a processing circuitry configured to:

- acquire a scheduled travel plan of a vehicle;
- create a charging plan in a case where charging is included in the scheduled travel plan;
- predict a battery temperature in the scheduled travel plan based on a cooling capacity of the battery temperature control device; and
- perform a power saving control for restricting a charging output of the external power supply when the temperature of the battery exceeds a predetermined temperature during the charging, and in which

the processing circuitry is configured to create,

when at least two times of charging are included in the scheduled travel plan and it is predicted that the charging output is restricted by the power saving control in a second and subsequent charging,

the charging plan such that a total time required for the charging included in the scheduled travel plan is shortened.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating a configuration of a charging control system 10.

FIG. 2 is a diagram illustrating a configuration of a temperature control device 16:

FIG. 3 is a diagram illustrating a configuration of a navigation device 17:

FIG. 4 is a diagram illustrating an example of a scheduled travel plan;

FIG. 5 is a graph illustrating a battery temperature prediction and an SOC of a battery in the scheduled travel plan;

FIG. 6 is a graph illustrating the battery temperature prediction and the SOC of the battery in a scheduled travel plan changed by a total charging time reduction control;

FIG. 7 is a diagram illustrating a temperature control capacity (chiller removed heat amount) of a battery temperature control device; and

FIG. 8 is a flowchart of the total charging time reduction control.

DESCRIPTION OF EMBODIMENTS

Hereinafter, an embodiment of a charging control system of the present disclosure will be described with reference to the accompanying drawings.

[Charging Control System]

As illustrated in FIG. 1, a charging control system 10 includes a battery BAT, a temperature control device 16, and a controller 20 that controls the battery BAT and the temperature control device 16, and is mounted on a vehicle such as an electrical vehicle.

[Battery]

The battery BAT is, for example, a secondary battery such as a lithium ion battery. The battery BAT is connected to (plugged in) an external power supply 50 outside the vehicle, for example, a rapid charger via a charging plug, and is configured to be charged with introduced electric power. The battery BAT mainly supplies the electric power to a drive motor (not illustrated). In addition, the battery BAT is also configured to be charged with electric power supplied at the time of regeneration of the drive motor.

[Temperature Control Device]

As illustrated in FIG. 2, the temperature control device 16 includes an air conditioning device (air conditioner) 18 and a battery temperature control circuit 19. Hereinafter, the air conditioning device 18 is referred to as an air conditioner 18. The air conditioner 18 includes a refrigeration cycle 180, and adjusts environment in a vehicle cabin by adjusting a state of air in the vehicle cabin. The air conditioner 18 is controlled by a temperature control unit 21, which will be described later, that receives an operation of an occupant (hereinafter, also referred to as a user). The battery temperature control circuit 19 cools or heats the battery BAT and the like by causing a refrigerant to flow through a refrigerant flow path. An operation of the battery temperature control circuit 19 is controlled by the temperature control unit 21 such that the temperature of the battery BAT becomes equal to or lower than a power saving temperature based on a temperature control capacity of the battery temperature control circuit 19. The power saving temperature is a threshold temperature at which a power saving control (output restriction control) of the battery BAT is performed, and includes threshold temperatures on a high temperature side and a low temperature side, but the power saving temperature of the present disclosure means the threshold temperature on the high temperature side which may be exceeded at the time of high-load traveling, rapid charging or the like.

In the temperature control device 16, the refrigeration cycle 180 of the air conditioner 18 and the battery temperature control circuit 19 are configured such that refrigerants of both can exchange heat with each other via a chiller 189.

More specifically, with reference to FIG. 2, in the refrigeration cycle 180 of the air conditioner 18, a compressor 181, a condenser 182, an expansion valve 183, and an evaporator 184 are provided in series, and a second flow path 185b in which another expansion valve 186 and the chiller 189 are disposed is provided in parallel with a first flow path 185a in which the expansion valve 183 and the evaporator 184 are disposed. In addition, a shutoff valve 187 is provided between the expansion valve 183 and a branch portion 185c of the first flow path 185a and the second flow path 185b, and the refrigerant flows to both the first flow path 185a and the second flow path 185b by setting the shutoff valve 187 to an ON state, and the refrigerant flows only to the second flow path 185b by setting the shutoff valve 187 to an OFF state.

In the battery temperature control circuit 19, a pump EWP for supplying the refrigerant, the chiller 189, the battery BAT, and a heater 30 are connected in series.

In the chiller 189, heat exchange is performed between the refrigerant of the refrigeration cycle 180 and the refrigerant of the battery temperature control circuit 19. Therefore, in the temperature control device 16, a cooling capacity of the refrigeration cycle 180 of the air conditioner 18 is distributed for the air conditioner and for battery cooling. That is, when the air conditioner 18 is not used (air conditioner OFF), the shutoff valve 187 is in the OFF state, and all the cooling capacity of the refrigeration cycle 180 can be used for the battery cooling. On the other hand, when the air conditioner 18 is used (air conditioner ON), the shutoff valve 187 is in the ON state, and the cooling capacity that can be used for the battery cooling among the cooling capacity of the refrigeration cycle 180 is reduced by an amount distributed for the air conditioner. Therefore, among the cooling capacity of the refrigeration cycle 180, the cooling capacity that can be used for the battery cooling depends on ON/OFF of the air conditioner 18. The temperature control capacity of the battery temperature control circuit 19 will be described later. When the battery BAT is heated, the heater 30 may be turned on.

[Navigation Device]

Next, an example of a configuration of the navigation device 17 will be described with reference to FIG. 3. As illustrated in FIG. 3, the navigation device 17 includes a processor 171, a memory 172, a GPS unit 173, a display unit 174, an operation unit 175, and an interface 176. Respective components 171 to 176 are connected to each other via a bus 177.

The processor 171 is, for example, a CPU that controls the entire navigation device 17. The memory 172 includes, for example, a main memory such as a RAM and an auxiliary memory which is a nonvolatile memory such as a flash memory. The main memory is used as a work area of the processor 171. The auxiliary memory stores various programs for operating the navigation device 17. The programs stored in the auxiliary memory are loaded into the main memory and are executed by the processor 171.

In addition, the auxiliary memory of the navigation device 17 also stores map data used for specifying a current position of the vehicle, making a route guidance to a destination, and the like. Although detailed description is omitted, the map data includes road data representing roads on which the vehicle can move, facility data representing information on each facility, and the like.

The GPS unit 173 receives GPS signals (radio waves) from GPS satellites and measures the current position of the vehicle. The current position measured by the GPS unit 173 is used to specify the current position of the vehicle.

The display unit 174 includes a display that displays characters and images, a graphic controller that controls the entire display, and a buffer memory such as a video RAM (VRAM) that temporarily records image data of an image to be displayed on the display. The display is, for example, a liquid crystal display or an organic EL display.

The operation unit 175 inputs an operation signal corresponding to an operation received from the user to an inside (for example, the processor 171) of the navigation device 17. The operation unit 175 is, for example, a touch panel. In addition, the operation unit 175 may be a remote controller, a keyboard, a mouse, or the like including a plurality of keys.

The interface 176 controls input and output of data between the navigation device 17 and an outside (for example, the controller 20). The interface 176 is controlled by the processor 171. Apart or all of the functions of the navigation device 17 may be implemented by, for example, functions of a terminal device such as a smartphone or a tablet terminal possessed by the user of the vehicle.

The navigation device 17 determines, for example, a route from a host vehicle position, which is the current position of the vehicle, to a destination set by the user of the vehicle with reference to the map data or the like. In addition, the navigation device 17 acquires state of charge (SOC) information of the battery BAT from a battery information acquisition unit 22, and creates a scheduled travel plan in which charging at a charging station is incorporated into a guidance route when charging is necessary. The scheduled travel plan includes the guidance route, the charging station, each required time, and the like. The navigation device 17 guides the user by displaying the created scheduled travel plan on the display.

[Control Device]

As illustrated in FIG. 1, the controller 20 includes the temperature control unit 21, the battery information acquisition unit 22, a charging control unit 23, a scheduled travel plan acquisition unit 24, a battery temperature prediction unit 25, and a charging plan creation unit 26. The controller 20 is implemented by an electronic control unit (ECU) including a processor, a memory, an interface, and the like. Incidentally, respective functional units may be configured as separate control devices.

The temperature control unit 21 controls the air conditioner 18 in accordance with a requirement of the user or the like, and controls the battery temperature control circuit 19 in accordance with the cooling capacity of the battery temperature control circuit 19.

The battery information acquisition unit 22 acquires a current temperature and a current cell voltage of the battery BAT from a sensor device (not illustrated), and estimates the SOC based on various kinds of information.

When the temperature of the battery BAT exceeds the power saving temperature, the charging control unit 23 performs the power saving control for restricting an output of the battery BAT. For example, when the temperature of the battery BAT exceeds the power saving temperature during the charging, the charging control unit 23 performs the power saving control for restricting a charging output (for example, a charging current) of the external power supply 50.

The scheduled travel plan acquisition unit 24 acquires the scheduled travel plan from the navigation device 17. FIG. 4 illustrates an example of the scheduled travel plan, and illustrates, for example, a scheduled travel plan in which charging is performed at a charging station CS1 at a location B and a charging station CS2 at a location C in the middle from a location A which is a departure point to a location D which is a destination. In the example illustrated in FIG. 4, the scheduled travel plan includes two times of charging, and a total travel distance is 300 km.

The battery temperature prediction unit 25 predicts a battery temperature based on the temperature control capacity of the battery temperature control circuit 19 according to the scheduled travel plan. The temperature control capacity of the battery temperature control circuit 19 is a cooling capacity that can be used for battery cooling in the temperature control device 16 when the battery BAT is cooled, and is an amount of heat by which the chiller 189 can lower the heat of the refrigerant of the battery temperature control circuit 19. Hereinafter, this amount of heat is referred to as a chiller removed heat amount.

The temperature control capacity of the battery temperature control circuit 19, that is, the chiller removed heat amount is determined based on a state of the vehicle and a state of the air conditioner 18. As illustrated in FIG. 7, the state of the vehicle is classified into, for example, five stages of a state in which the vehicle is parked in a plug-out state (Plug-out parked (IG-OFF)), traveling, normal charging, rapid charging, and a state in which the vehicle is parked in a plug-in state (Plug-in parked (IG-OFF)). The state of the air conditioner 18 is classified into three stages of a state in which the air conditioner 18 is OFF (A/C_OFF), a state in which the air conditioner 18 is in an air conditioner priority mode (air conditioner priority mode), and a state in which the air conditioner 18 is ON (A/C_ON). The air conditioner priority mode is a mode in which a temperature of the vehicle cabin is actively controlled when the vehicle is started.

In addition, the temperature control capacity is classified into five chiller cooling modes according to combinations of the state of the vehicle and the state of the air conditioner 18. The chiller cooling modes include six stages of anon-cooling mode, the air conditioner priority mode, an A/C cooperation chiller cooling mode, a vehicle stop and A/C cooperation chiller cooling mode, a chiller independent operation mode, and a vehicle stop and chiller independent operation mode. Cooling capacities (0<W1<W3<W2<W5<W4) are set for the six stages of modes, respectively. Therefore, the charging control unit 23 can calculate, based on the scheduled travel plan, a battery temperature prediction and the temperature control capacity of the battery temperature control circuit 19, that is, the chiller removed heat amount. The battery temperature prediction unit 25 may acquire weather information from a weather information server via a communication device (not illustrated) and derive a battery temperature prediction based on the temperature control capacity of the battery temperature control circuit 19 and the weather information.

FIG. 5 illustrates the battery temperature prediction calculated by the battery temperature prediction unit 25 together with the scheduled travel plan. In the battery temperature prediction illustrated in FIG. 5, a region (power saving region) in which the battery temperature prediction exceeds the power saving temperature is generated in the second charging.

When at least two times of charging are included in the scheduled travel plan and it is predicted that the charging output is restricted by the power saving control in the second and subsequent charging, the charging plan creation unit 26 creates the charging plan such that the total time required for the charging included in the scheduled travel plan is shortened. Hereinafter, this control may be referred to as the total charging time reduction control.

In a normal charging control of the battery (hereinafter, referred to as a normal battery charging control), in order to control a time until the battery reaches a target SOC to be shortest, as illustrated in FIG. 5, in the first charging, the charging is completed within a charging time of 15 minutes without exceeding the power saving temperature, but in the second charging, a charging current is restricted by the power saving control, and the charging time may be extended to 30 minutes.

On the other hand, in FIG. 6, in the first charging, by limiting the charging output more than in the normal charging in FIG. 5, the charging time is extended by 5 minutes, and the charging is completed within 20 minutes. In addition, in the second charging, the charging is completed within a charging time of 20 minutes without exceeding the power saving temperature. When FIG. 5 and FIG. 6 are compared, it can be seen that a total required time (40 minutes) of the charging in the total charging time reduction control in FIG. 6 is shorter by 5 minutes than a total required time (45 minutes) of the charging in the normal battery charging control in FIG. 5. An amount of electric power (kw·h) stored in the battery BAT by two times of charging in the normal battery charging control in FIG. 5 is equal to an amount of electric power (kw·h) stored in the battery BAT by two times of charging in the total charging time reduction control in FIG. 6.

In addition, an amount of heat (kJ) received by the battery BAT in the two times of charging in the normal battery charging control in FIG. 5 is equal to an amount of heat (kJ) received by the battery BAT in the two times of charging in the total charging time reduction control in FIG. 6. Hereinafter, the amount of heat received by the battery BAT in the charging included in the scheduled travel plan is also referred to as a total amount of heat. The total amount of heat (kJ) of the battery BAT is a sum of the amount of heat (kJ) of the battery BAT in each charging derived from a battery loss (kW) and the charging time. The battery loss (heat generation amount) may be acquired based on a table in which the charging output (kW) and the battery loss (kW) are associated with each other, may be calculated based on a calculation formula, or may be estimated based on a map.

As described above, when one time of charging is included in the scheduled travel plan, the normal battery charging control in FIG. 5 is effective for shortening the destination arrival time, and when two or more times of charging are included in the scheduled travel plan, the destination arrival time can be shortened by managing the charging in consideration of the total required time in the two or more times of charging. That is, when the amount of heat received by the battery BAT in the first charging is large, there is a possibility that the power saving control is performed due to an affection on the second and subsequent charging, but the destination arrival time can be shortened by planning each charging in advance in consideration of the total required time.

FIG. 8 is a flowchart of the total charging time reduction control.

First, the scheduled travel plan acquisition unit 24 acquires the scheduled travel plan from the navigation device 17 (S1). Subsequently, the battery temperature prediction unit 25 predicts the battery temperature based on the temperature control capacity of the battery temperature control circuit 19 according to the scheduled travel plan (S2). Subsequently, the charging plan creation unit 26 determines whether the scheduled travel plan includes at least two times of charging (S3), and when the scheduled travel plan does not include at least two times of charging (NO in S3), the process ends. When the scheduled travel plan includes at least two times of charging (YES in S3), the charging plan creation unit 26 determines whether it is predicted that the charging output is restricted by the power saving control in the second and subsequent charging (S4). When the charging output is not restricted by the power saving control (NO in S4), the process ends.

On the other hand, when it is predicted that the charging output is restricted by the power saving control in the second and subsequent charging (YES in S4), the charging plan creation unit 26 calculates a total amount of heat of the battery BAT in n times of charging included in the scheduled travel plan (S5).

In addition, the scheduled travel plan acquisition unit 24 creates a charging plan so as to satisfy the total amount of heat and shorten the total time required for the charging included in the scheduled travel plan (S6), and determines whether the created charging plan satisfies the temperature control capacity of the battery temperature control circuit 19 (S7).

It is preferable that the charging plan creation unit 26 creates the charging plan such that the total time required for the charging included in the scheduled travel plan becomes short and a difference in charging time of each charging becomes small. As a result, it is possible to avoid giving the user an uncomfortable feeling due to the difference in charging time in a plurality of times of charging in a travel route.

For example, the charging plan creation unit 26 creates a charging plan so as to perform charging with a charging output smaller than a charging output at which the battery BAT can be charged earliest in the charging system in which the first charging is performed, and thus can perform an adjustment such that the total time required for the charging included in the scheduled travel plan is shortened and the difference in charging time of each charging is reduced.

When the created charging plan does not satisfy the temperature control capacity of the battery temperature control circuit 19 (NO in S7), the charging plan is changed by further reducing the charging output in the first charging, and the processing is repeated until the temperature control capacity of the battery temperature control circuit 19 is satisfied. The expression of “not satisfying the temperature control capacity of the battery temperature control circuit 19” means that the temperature of the battery BAT cannot be controlled according to the created charging plan and the temperature of the battery BAT exceeds the power saving temperature because the temperature control capacity of the battery temperature control circuit 19 is insufficient.

On the other hand, when the created charging plan satisfies the temperature control capacity of the battery temperature control circuit 19 (YES in S7), the charging plan is transmitted to the navigation device 17, and the navigation device 17 changes the scheduled travel plan. The expression of “satisfying the temperature control capacity of the battery temperature control circuit 19” means that the temperature of the battery BAT can be controlled according to the created charging plan and the charging can be completed within the charging time according to the plan.

Although embodiments for carrying out the present disclosure have been described above using the embodiment, the present disclosure is by no means limited to these embodiments, and various modifications and substitutions can be made without departing from the gist of the present disclosure.

Further, at least the following matters are described in the present description. Although corresponding constituent elements and the like in the above embodiment are shown in parentheses, the present disclosure is not limited thereto.

(1) A charging control system (charging control system 10) including: a battery (battery BAT) rechargeable with electric power from an external power supply (external power supply 50);

a battery temperature control device (battery temperature control circuit 19) that adjusts a temperature of the battery; and

a controller (controller 20) that controls the battery and the battery temperature control device, in which

the control device includes

a scheduled travel plan acquisition unit (scheduled travel plan acquisition unit 24) that acquires a scheduled travel plan of a vehicle;

a charging plan creation unit (charging plan creation unit 26) that creates a charging plan in a case where charging is included in the scheduled travel plan;

a battery temperature prediction unit (battery temperature prediction unit 25) that predicts a battery temperature in the scheduled travel plan based on a cooling capacity of the battery temperature control device; and

a charging control unit (charging control unit 23) that performs a power saving control for restricting a charging output of the external power supply when the temperature of the battery exceeds a predetermined temperature during the charging, and

the charging plan creation unit creates,

the charging plan such that a total time required for the charging included in the scheduled travel plan is shortened.

According to (1), since the charging plan is included in the scheduled travel plan, the user can more accurately know the destination arrival time without worrying about the vehicle becoming unable to travel due to lack of power. In addition, when at least two times of charging are included in the scheduled travel plan, the charging plan is created based on a long-term battery temperature prediction such that the total time required for the charging included in the scheduled travel plan is shortened. As a result, it is possible to avoid the power saving control being performed in the second and subsequent charging, and it is possible to shorten the destination arrival time.

(2) The charging control system according to (1), in which

the charging plan creation unit

calculates a total amount of heat of the battery in all the charging included in the scheduled travel plan, and

creates the charging plan based on the total amount of heat of the battery.

According to (2), by calculating the total amount of heat of the battery in all the charging in the scheduled travel plan, it is easy to create the charging plan.

(3) The charging control system according to (1) or (2), in which

the charging plan creation unit

creates the charging plan such that the total time required for the charging included in the scheduled travel plan is shortened and a difference in charging time of each charging is reduced.

According to (3), since the difference in charging time of the charging included in the scheduled travel plan becomes small, it is possible to avoid giving the user an uncomfortable feeling due to the difference in charging time in the plurality of times of charging in the travel route.

(4) The charging control system according to any one of (1) to (3), in which

the charging plan creation unit

creates the charging plan such that the charging is performed with a charging output smaller than a charging output at which the battery can be charged earliest in a charging system in which a first charging is performed.

According to (4), the amount of heat accumulated in the battery by the first charging affects the second and subsequent charging, and the charging output may be restricted in the second and subsequent charging. Therefore, the destination arrival time can be shortened by reducing the charging power in the first charging to reduce the amount of heat accumulated in the battery by the first charging.

(5) The charging control system according to any one of (1) to (4), in which

the battery temperature prediction unit

predicts the battery temperature based on the cooling capacity of the battery temperature control device and weather information.

According to (5), the accuracy of the long-term battery temperature prediction is improved, and thus the destination arrival time can be accurately estimated.

CHARGING CONTROL SYSTEM

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