JP2024072650A - Battery temperature control method and battery temperature control device - Google Patents

Abstract

[Problem] To suppress the burden of charging power amount borne by a vehicle user. [Solution] When an external charging request signal Sc indicating a request to execute external charging of a battery 34 mounted on an electric vehicle is received, a first temperature control judgment (S400) is performed to judge whether or not to execute pre-temperature control (S600) for warming or cooling the battery 34, and if the result of the first temperature control judgment is positive, the pre-temperature control is executed. In particular, in the first temperature control judgment, a charging gain amount GB indicating an increase in the amount of charging power due to execution of the pre-temperature control is calculated (S401), a temperature control power consumption amount ΔEb_temc indicating the amount of power consumed by execution of the pre-temperature control is calculated, and if the charging gain amount GB exceeds the temperature control power consumption amount ΔEtemc, it is determined that the pre-temperature control should be executed (S403, S404). [Selected Figure] FIG.

Description

The present invention relates to a battery temperature control method and a battery temperature control device.

Patent Document 1 discloses a battery temperature control device that performs control (pre-temperature control) to adjust the battery temperature by cooling or warming the battery in advance when charging the on-board battery with a charging facility. In particular, the battery temperature control device of Patent Document 1 performs pre-temperature control when it is determined that the battery needs to be charged based on the battery's state of charge (SOC) while the electric vehicle is running, so that the battery temperature approaches a target temperature during the time required from the time of the determination to the time required to reach the next charging point.

Patent No. 5517644

By appropriately setting the target temperature when performing pre-temperature control, the amount of charging power obtained can be increased compared to when pre-temperature control is not performed. However, depending on the driving scene of the electric vehicle, the amount of power consumed by the pre-temperature control may exceed the increase in the amount of charging power due to the execution of pre-temperature control. This creates a problem in that the burden of the actual amount of charging power borne by the vehicle user during external charging increases.

Therefore, the object of the present invention is to provide a battery temperature control method and a battery temperature control device that can reduce the burden of charging power on the vehicle user.

According to one aspect of the present invention, when an external charging request signal indicating a request to perform external charging of a battery mounted on an electric vehicle is received, a first temperature control determination is made to determine whether or not to perform pre-temperature control to warm or cool the battery, and if the result of the first temperature control determination is positive, the pre-temperature control is performed.

In particular, in the first temperature control judgment, a charging gain amount indicating the increase in the amount of charging power due to the execution of pre-temperature control is calculated, and a temperature control power consumption amount indicating the amount of power consumed by the execution of pre-temperature control is calculated, and it is determined that pre-temperature control should be executed if the charging gain amount exceeds the temperature control power consumption amount.

The present invention makes it possible to reduce the burden of charging power on the vehicle user.

FIG. 1 is a block diagram showing a configuration of a vehicle system common to each embodiment of the present invention. FIG. 2 is a diagram showing the configuration of an in-vehicle cooling system for controlling the temperature of a battery. FIG. 3 is a flowchart showing the overall process of the battery temperature adjustment method according to the first embodiment. FIG. 4A is a flowchart illustrating the details of the preliminary judgment. FIG. 4B is a block diagram showing a detailed configuration of the preliminary determination unit. FIG. 5A is a flowchart illustrating the details of the first temperature adjustment determination. FIG. 5B is a block diagram showing a detailed configuration of the first temperature adjustment determination unit. FIG. 6 is a flowchart illustrating the details of the pre-temperature adjustment control. FIG. 7 is a flowchart illustrating the details of the end determination. FIG. 8 is a timing chart showing an example of a control result according to the battery temperature control method of the first embodiment. FIG. 9 is a flowchart showing the overall process of the battery temperature adjustment method according to the second embodiment. FIG. 10A is a flowchart illustrating the details of the second temperature adjustment determination. FIG. 10B is a block diagram showing a detailed configuration of the second temperature adjustment determination unit. FIG. 11 is a timing chart showing an example of a control result according to the battery temperature control method of the second embodiment.

Each embodiment of the present invention will be described below with reference to the drawings.

[Prerequisite configuration]
Fig. 1 is a block diagram showing a configuration of a vehicle system 1 common to each embodiment described later. The vehicle system 1 shown in Fig. 1 is mounted on an electric vehicle. The concept of an electric vehicle in this specification includes an electric vehicle (EV) or a hybrid vehicle (HEV) that uses an electric motor as a driving source to drive the vehicle.

More specifically, the vehicle system 1 is mainly composed of sensors 10, a navigation system 20, a temperature control system 30 in which a battery 34 is arranged, and a controller 50.

The sensors 10 detect various parameters that indicate the vehicle status of the electric vehicle, including when the vehicle is running and when the vehicle is stopped. In particular, the sensors 10 in this embodiment include a battery temperature sensor 12 and a state-of-charge sensor 14. The battery temperature sensor 12 detects a current battery temperature T _B (hereinafter referred to as a “current battery temperature T _{B_c} ”) and outputs the detected value to the controller 50. The state-of-charge sensor 14 detects a current charging rate of the battery 34 (hereinafter referred to as a “current _{SOC_c} ”) and outputs the detected value to the controller 50.

The navigation system 20 generates an external charging request signal S _c in response to an input operation by a user of the electric vehicle (hereinafter referred to as the "vehicle user"). The navigation system 20 also acquires information (charger output P _c ) related to the output of an external charger in charging equipment specified by the vehicle user. The charger output P _c is a parameter determined according to the rated charging power determined for the external charger, etc. The navigation system 20 also calculates a predicted travel time Δt _tra from the current location to the charging equipment from the average vehicle speed and driving route of the electric vehicle, etc. Then, the navigation system 20 outputs the external charging request signal S _c , the charger output P _c , and the predicted travel time Δt _tra to the controller 50.

The controller 50 controls the temperature adjustment system 30 using as input various detection signals (particularly, the current battery temperature T _{B_c} and the current _{SOC_c} , etc.) obtained by the sensors 10 and various signals (particularly, the external charging request signal S _c , the charger output P _c , and the predicted travel time Δt _tra , etc.) from the navigation system 20. The controller 50 is configured by a computer including, for example, a central processing unit (CPU), a read-only memory (ROM), a random access memory (RAM), and an input/output interface (I/O interface), and is programmed to execute processes defined in each embodiment described below. In particular, the functions of the controller 50 can be realized by a vehicle controller (VCM) that comprehensively controls each part of the electric vehicle.

More specifically, the controller 50 includes a temperature control determination unit 51, a pre-temperature control control unit 55, and an end determination unit 56.

The temperature adjustment determination unit 51 determines whether or not pre-temperature adjustment control should be performed based on various input information. In particular, the temperature adjustment determination unit 51 includes a preliminary determination unit 52, a first temperature adjustment determination unit 53, and a second temperature adjustment determination unit 54. The pre-temperature adjustment control unit 55 warms up or cools the battery 34 in the temperature adjustment system 30 according to the determination result of the temperature adjustment determination unit 51. The termination determination unit 56 determines whether or not to terminate the pre-temperature adjustment control while the pre-temperature adjustment control is being performed. Details of the processing in the temperature adjustment determination unit 51, the pre-temperature adjustment control unit 55, and the termination determination unit 56 will be described later.

The temperature control system 30 includes on-board temperature control devices such as an electric motor unit 32 and a battery 34, and a temperature control actuator 36 for performing temperature control operations (warming or cooling) on the temperature control devices.

Figure 2 is a diagram illustrating the configuration of the temperature control system 30. As shown in the figure, in the temperature control system 30 of this embodiment, the electric motor unit 32 and the battery 34, which are temperature control target devices, are arranged in a common cooling circuit C.

The electric motor unit 32 is mainly composed of a motor 321 that functions as a driving source for the electric vehicle, and an inverter 322 that adjusts the power supplied to the motor 321.

The battery 34 is electrically connected to the motor 321 via the inverter 322, and discharges power during power running to supply driving power to the motor 321, while receiving regenerative power from the motor 321 during regeneration to be charged.

The temperature control system 30 also includes a chiller 301, cooling water pumps 302-1 and 302-2, valves 303-1 to 303-4, a PTC heater 304, and a radiator 305 as temperature control actuators 36.

The chiller 301 is a device that exchanges heat between the liquid refrigerant supplied to an air conditioner heat exchange circuit (such as an air conditioning condenser) (not shown) and the cooling water of the cooling circuit C.

Cooling water pumps 302-1 and 302-2 adjust the flow rate of cooling water in cooling circuit C.

Each valve 303-1 to 303-4 switches the flow path of cooling water between the chiller 301, the radiator 305, the motor unit 32, and the battery 34.

The PTC heater 304 heats the coolant (particularly the coolant flowing into the battery 34). The radiator 305 dissipates the heat contained in the coolant in the cooling circuit C by heat exchange with the outside air.

In the temperature control system 30, the warming up of the battery 34 during pre-temperature control can be performed by operating the PTC heater 304. Also, the cooling of the battery 34 during pre-temperature control can be performed by adjusting the amount of coolant that is dissipated by the radiator 305 and flows into the battery 34 by individually operating the valves 303-1 to 303-4, or by operating the chiller 301 (in particular, by adjusting the compressor output).

The battery temperature control method according to each embodiment is described in detail below.

[First embodiment]
3 is a flow chart showing the overall process in the battery temperature control method according to the first embodiment. Each process shown in FIG. 3 is repeatedly executed by each section of the controller 50 at a predetermined calculation cycle.

As shown in the figure, in the battery temperature control method of this embodiment, when an external charging request signal _Sc is received (S100), a preliminary judgment (S200) is executed. Here, the preliminary judgment is a predetermined judgment for screening a situation in which a pre-temperature control should be executed preliminarily before executing a first temperature control judgment described later. The details of the preliminary judgment are described below.

(Preliminary Ruling)
4A is a flowchart for explaining the details of the preliminary judgment, and FIG.

As shown in the figure, in the preliminary determination, first, the current _{SOC_c} is used as an input to calculate the charging _{SOC_es} (S201, estimated state of charge calculation unit 521). The charging _{SOC_es} is an estimated value of the battery SOC during charging (at the time of arrival at the charging facility) that takes into account the amount of power consumed during travel from the current location to the target charging facility, without considering the power consumed during the execution of the pre-temperature adjustment control. The charging _{SOC_es} can be obtained, for example, by calculating the amount of power consumed during travel from the travel distance and estimated average vehicle speed on the travel route from the current location of the electric vehicle to the target charging facility, and subtracting an SOC equivalent to the amount of power consumed during travel from the current _{SOC_c} . It is also possible to adopt a configuration in which the charging _{SOC_es} is calculated in the navigation system 20 and the controller 50 acquires it.

Next, based on the calculated charging _{SOC_es} and charger output _Pc , a target temperature map stored in advance in memory is referenced to calculate a target charging temperature T _{B_t} (S202, target charging temperature calculation unit 522).

Here, the charging target temperature T _{B_t} is a target value of the battery temperature T B during charging in order to achieve a desirable charging efficiency (charging speed) while avoiding electrolytic deposition when charging (especially rapid charging) the battery ₃₄ using an external charger.

Next, the current battery temperature T _{B_c} is input and an estimated charging temperature T _{B_es} is calculated (S203, estimated charging temperature calculation unit 523).

Here, the estimated charging temperature T _{B_es} is an estimate of the battery temperature T _B when the electric vehicle arrives at the charging facility and starts charging the battery 34 by the external charger.

The estimated charging temperature T _{B_es} is calculated, for example, by adding an estimated increase in the battery temperature T _B according to the amount of power consumed during traveling to the current battery temperature T _{B_c} . In particular, this estimated increase can be calculated by multiplying the amount of power consumed during traveling by a known heat loss coefficient K _loss to calculate a total amount of heat generated by the battery during the traveling process Q _b and dividing this total amount of heat generated by the battery Q _b by a known battery heat capacity. The estimated charging temperature T _{B_es} may be determined in consideration of the upper and lower limits of _{a battery temperature range maintained by basic temperature adjustment control of the battery 34. More specifically, when a basic calculation value of the estimated charging temperature T B_es determined} by adding the estimated increase to the current battery temperature T _{B_c} exceeds the upper limit of the battery temperature range, the basic calculation value may be replaced with this upper limit to set the estimated charging temperature T _{B_es} . Furthermore, when the basic calculation value of the estimated charging temperature T _{B_es} is below the lower limit of the battery temperature range, the basic calculation value may be replaced with this lower limit to be used as the estimated charging temperature T _{B_es} .

Next, the estimated charging temperature T _{B_es} is subtracted from the calculated charging target temperature T _{B_t} to obtain an estimated temperature difference ΔT _{B_t-es} (subtractor 524).

Then, the calculated estimated temperature difference ΔT _{B_t-es} is compared with a threshold temperature difference A stored in advance in memory (S204). If the estimated temperature difference ΔT _{B_t-es} exceeds the threshold temperature difference A, the preliminary determination flag _fp is set to ON, and if not, the preliminary determination flag _fp is set to OFF (S205, S206, preliminary determination flag setting unit 525).

Here, the threshold temperature difference A is set to an appropriate value from the viewpoint of screening the scenes in which the execution of the pre-temperature control leads to a situation in which an increase in the substantial amount of charging power can be obtained. In other words, the threshold temperature difference A serves as an index for determining a situation in which it is meaningless to execute the pre-temperature control without even having to execute the first temperature control judgment described below.

3, if the preliminary judgment flag _fp is set to OFF in the preliminary judgment (No in S300), this routine ends, and if it is set to ON (Yes in S300), the process proceeds to the first temperature adjustment judgment (S400). The details of the first temperature adjustment judgment will be described below.

(First temperature control judgment)
Fig. 5A is a flowchart illustrating the details of the first temperature adjustment determination, and Fig. 5B is a block diagram showing the detailed configuration of first temperature adjustment determination unit 53.

As shown in the figure, in the first temperature control judgment, the charger output _Pc , the charging target temperature T _{B_t} , the charging _{SOC_es} , and the charging estimated temperature T _{B_es} obtained during the preliminary judgment are input, and the charging gain amount G _B is calculated (S401, charging gain amount calculation unit 531).

Here, the charge gain amount G _B is a parameter indicating an increase in the amount of charging power during external charging obtained by executing the pre-temperature adjustment control. More specifically, when the pre-temperature adjustment control is executed, the battery temperature T _B becomes an appropriate value, so that the charging efficiency is higher than when the pre-temperature adjustment control is not executed, and the amount of charging power obtained per charging is increased. The charge gain amount G _B is determined as a value that quantifies this increase in the amount of charging power.

More specifically, the charge gain amount G _B is calculated as follows. First, the charger output P _c , the estimated charging temperature T _{B_es} , and the charging SOC _{_es} are input, and a first estimated charging energy amount ΔE _{b_es1} suggesting the amount of charging energy when it is assumed that the pre-temperature adjustment control is not performed is calculated by referring to a first charging amount map 531a stored in advance in a memory. Also, the charger output P _c , the charging target temperature T _{B_t} , and the charging SOC _{_es} are input, and a second estimated charging energy amount ΔE b_es2 suggesting the amount of charging energy when it is assumed that the pre-temperature adjustment control is performed is calculated by referring to a first charging amount map 531b stored in a memory. Then, the charge gain amount _{G B can} be determined by subtracting the first estimated charging energy amount ΔE _{b_es1} from the second estimated charging energy amount ΔE _{b_es2} (subtraction unit 531c).

In the first temperature adjustment judgment, the temperature adjustment power consumption W _temc and the temperature adjustment execution time Δt _temc are input to calculate the temperature adjustment power consumption ΔE _temc (S402, temperature adjustment power consumption calculation unit 532).

The temperature control power consumption W _temc used in the calculation is a parameter indicating the power required to operate the temperature control actuator 36 during pre-temperature control. The temperature control execution time Δt _temc is a parameter indicating the time during which the pre-temperature control will continue. The temperature control power consumption W _temc and the temperature control execution time Δt _temc can use feedback values of the calculation results in the pre-temperature control (S600) described later.

Next, the calculated charging gain amount G _B and the temperature adjustment power consumption amount ΔE _temc are compared in magnitude. If the charging gain amount G _B is greater than the temperature adjustment power consumption amount ΔE _temc , the first temperature adjustment judgment flag f ₁ is set to ON, and if not, the first temperature adjustment judgment flag f ₁ is set to OFF (S403, S404, S405, subtractor 533, first temperature adjustment judgment flag setting unit 534).

Returning to FIG. 3, if the first temperature adjustment judgment flag _f1 is set to OFF in the first temperature adjustment judgment (No in S500), this routine is terminated, and if it is set to ON (Yes in S500), the routine proceeds to pre-temperature adjustment control (S600).

(Pre-temperature control)
FIG. 6 is a flowchart illustrating the details of the pre-temperature adjustment control.

As shown in the figure, in the pre-temperature adjustment control, a charge target temperature T _{B_t} and a charge estimated temperature T _{B_es} are compared in magnitude (S601).

If the charging target temperature T _{B_t} is lower than the charging estimated temperature T _{B_es} , the PTC heater 304 is operated to warm up the battery 34 (S603).

On the other hand, if the charging target temperature T _{B_t} is greater than the charging estimated temperature T _{B_es} , it is further determined whether or not cooling by the chiller 301 is necessary (S602). More specifically, for example, if the temperature difference between the current battery temperature T _{B_c} and the outside air temperature is equal to or less than a predetermined threshold (if the radiator 305 cannot ensure a sufficient amount of cooling), it is determined that the chiller 301 should be operated. On the other hand, if the temperature difference exceeds the predetermined threshold (if the radiator 305 can ensure a sufficient amount of cooling), cooling is performed by the radiator 305 (the chiller 301 is not operated).

If the result of the determination in S602 is positive, the chiller 301 is operated to cool the battery 34 (S604). On the other hand, if the result of the determination in S602 is negative, the battery 34 is cooled by the radiator 305 (S605).

Thereafter, the temperature control power consumption ΔE _temc corresponding to the warming or cooling of the battery 34 is calculated (S606) and fed back to the first temperature control judgment. More specifically, the temperature control power consumption ΔE _temc is obtained by calculating the time required for temperature control (hereinafter also referred to as the “required temperature control time Δt _req ”) based on the required temperature control amount (required temperature control amount) and the warming/cooling performance of each temperature control actuator 36, and multiplying the required temperature control time Δt _req by the power consumption of each temperature control actuator 36. In addition, the temperature control amount can be estimated based on the difference between the charging target temperature T _{B_t} and the charging estimated temperature T _{B_es} . In particular, the temperature control power consumption ΔE _temc during warming can be determined based on the output of the PTC heater 304. In addition, the temperature control power consumption ΔE _temc during cooling can be determined based on the power consumption of the compressor of chiller 301 when chiller 301 is used for cooling, and can be determined based on the power consumption of cooling water pumps 302-1, 302-2 when radiator 305 is used.

Returning to FIG. 3, an end determination (S700) is made while pre-temperature control is being performed.

(End judgment)
FIG. 7 is a flowchart illustrating the details of the end determination.

As shown in the figure, the termination judgment involves judging whether the estimated temperature difference ΔT _{B_t-es} calculated by the preliminary judgment unit 52 is greater than or equal to the threshold temperature difference A, and whether the charging gain amount G _B is greater than or equal to the temperature control power consumption amount ΔE _temc (S701, S702).

If all the determination results are positive, the end determination flag _ff is set to OFF (S703).On the other hand, if any of the determination results are negative, the end determination flag _ff is set to ON (S703).

3, if the termination flag _ff is set to ON in the termination determination (Yes in S800), the pre-temperature adjustment control is terminated (S900). On the other hand, if the termination flag _ff is set to OFF (No in S800), the pre-temperature adjustment control (S600) is continued.

The following describes the control results of the battery temperature control method of this embodiment.

8 is a timing chart showing an example of the control result by the battery temperature adjustment method of the present embodiment. In FIG. 8, a cooling scene for lowering the battery temperature T _B to the charging target temperature T _{B_t} is assumed as the pre-temperature adjustment control.

As shown in the figure, the preliminary determination (S200) is started at time t1 when the external charging request signal S _c is received. Here, during the preliminary determination, the pre-temperature adjustment control is not executed. Therefore, theoretically, the estimated charging temperature T _{B_es} calculated during the preliminary determination is a constant value. On the other hand, in a real driving scene of an electric vehicle, an error occurs in the calculation of the estimated charging temperature T _{B_es} depending on the driving state (frequency of acceleration/deceleration, traffic congestion, etc.) during the movement process from the current location to the charging facility. Therefore, from time t1 to time t3 in FIG. 8, an example is shown in which the estimated charging temperature T _{B_es} increases over time due to the influence of this error.

Due to the increase in the estimated charging temperature T _{B_es} , the estimated temperature difference ΔT _{B_t-es} determined by the difference between the estimated charging temperature T _{B_es} and the charging target temperature T _{B_t} also increases and approaches the threshold temperature difference A. Then, at time t2 when the estimated temperature difference ΔT _{B_t-es} reaches the threshold temperature difference A, the preliminary determination flag _fp is switched from OFF to ON. Therefore, the first temperature adjustment determination (S400) is started from time t2.

The first temperature adjustment judgment continues from time t2 to time t3 when the charge gain amount G _B falls below the temperature adjustment power consumption amount ΔE _temc . Then, at time t3 when the charge gain amount G _B starts to exceed the temperature adjustment power consumption amount ΔE _temc , the first temperature adjustment judgment flag _f1 is switched from OFF to ON. Therefore, pre-temperature adjustment control (particularly cooling of the battery 34) is started from time t3. At the same time, the end judgment (S700) is also started.

After time t3 when cooling of the battery 34 is started, the estimated charging temperature T _{B_es} calculated taking into account the effect of the cooling decreases over time, and the estimated temperature difference ΔT _{B_t-es} also decreases.

Thereafter, at time t4 when the estimated temperature difference ΔT _{B_t-es} has decreased to the threshold temperature difference A, the end determination flag f _f is switched from OFF to ON. This ends the pre-temperature adjustment control. In the example shown in FIG. 8, the vehicle arrives at the charging facility at time t5 while the state in which the pre-temperature adjustment control is not being executed continues after time t4. On the other hand, a configuration may be adopted in which the processing from the preliminary determination onward is repeated again even after the pre-temperature adjustment control has been ended.

The configuration of the battery temperature control method of this embodiment and the resulting effects will now be explained.

In the battery temperature control method of this embodiment, when an external charging request signal _Sc indicating a request to perform external charging of the battery 34 mounted on an electric vehicle is received, a first temperature control determination (S400) is made to determine whether or not to perform pre-temperature control (S600) to warm up or cool the battery 34, and if the result of the first temperature control determination is positive, the pre-temperature control is executed.

In particular, in the first temperature control judgment, a charging gain amount _{G_B} indicating the increase in the amount of charging power due to the execution of pre-temperature control is calculated (S401), and a temperature control power consumption amount _{ΔE_b_temc} indicating the amount of power consumed by the execution of pre-temperature control is calculated, and if the charging gain amount _{G_B} exceeds the temperature control power consumption amount _{ΔE_temc} , it is determined that pre-temperature control should be executed (S403, S404).

This allows the system to properly detect situations in which the amount of power saved by shortening the charging time exceeds the amount of power consumed by the pre-temperature control, and to execute the pre-temperature control in those situations. Therefore, the system can execute the pre-temperature control in situations in which a substantial gain in the amount of charging power can be obtained, thereby reducing the burden of the amount of charging power borne by the vehicle user.

In addition, in this embodiment, when an external charging request signal _Sc is received, a preliminary judgment (S200) is further performed to judge whether or not to perform a first temperature control judgment, and if the result of the preliminary judgment is positive, the first temperature control judgment is performed.

In particular, in the preliminary determination, a charging target temperature T _{B_t} that the battery temperature T _B should reach during charging is calculated (S202), an estimated charging temperature T _{B_es} that is the estimated battery temperature during charging is calculated (S203), and an estimated temperature difference ΔT _{B_t-es} given as the difference between the estimated charging temperature T _{B_es} and the charging target temperature T _{B_t} is calculated. Then, when the estimated temperature difference ΔT _{B_t-es} exceeds a predetermined threshold temperature difference A, it is determined that a first temperature adjustment determination should be performed.

This allows the system to perform a preliminary screening of scenes where pre-temperature control should be performed, and then executes the first temperature control judgment, reducing the computational burden.

In the first temperature adjustment judgment, a first estimated amount of charging energy ΔE _{b_es1} , which is the amount of charging energy when it is assumed that the pre-temperature adjustment control is not executed, is calculated based on the estimated charging temperature T _{B_es} , and a second estimated amount of charging energy ΔE _{b_es2} , which is the amount of charging energy when it is assumed that the pre-temperature adjustment control is executed, is calculated based on the target charging temperature T _{B_t} . Also, a charging gain amount G _B is calculated based on the difference between the first estimated amount of charging energy ΔE _{b_es1} and the second estimated amount of charging energy ΔE _{b_es2} (charging gain amount calculation unit 531).

This realizes a specific control logic for determining the charging gain amount G _B using the parameters used in the preliminary determination.

During the execution of the pre-temperature control, an end judgment is executed (S700) to judge whether or not to end the pre-temperature control, and if the result of the end judgment is affirmative, the pre-temperature control is ended. In particular, in the end judgment, if the estimated temperature difference ΔT _{B_t-es} falls below the threshold temperature difference A, or falls below the charging gain amount G _B and the temperature adjustment power consumption amount ΔE _{b_temc} , it is determined that the pre-temperature control should be ended (S701, S702, S704).

As a result, even when pre-temperature control is being performed based on the results of the preliminary judgment and the first temperature control judgment, if a situation arises in which the pre-temperature control should be interrupted, this can be appropriately detected and the pre-temperature control can be terminated.

Furthermore, in the pre-temperature adjustment control (S600) of this embodiment, when the estimated charging temperature T _{B_es} is lower than the target charging temperature T _{B_t} , the battery 34 is warmed up, and when the estimated charging temperature T _{B_es} is higher than the target charging temperature T _{B_t} , the battery 34 is cooled.

This makes it possible to appropriately execute warming and cooling in the pre-temperature adjustment control depending on whether the battery temperature T _B is lower than or higher than the charging target temperature T _{B_t} during external charging.

In particular, in this embodiment, during cooling, the chiller 301 or the radiator 305 is used as the temperature control actuator 36. More specifically, if the desired amount of cooling can be ensured by the radiator 305, cooling is performed using the radiator 305, and if not, cooling is performed by operating the chiller 301. This allows the battery 34 to be cooled more efficiently during pre-temperature control.

In this embodiment, a controller 50 is provided that functions as a battery temperature control device suitable for executing the above-mentioned battery temperature control method.

This controller 50 has a first temperature control judgment unit 53 that judges whether or not to execute pre-temperature control (S600) for warming up or cooling the battery 34 when it receives an external charging request signal _Sc indicating a request to execute external charging of the battery 34 mounted on the electric vehicle, and a pre-temperature control unit 55 that executes pre-temperature control when the result of the first temperature control judgment is positive.

In particular, the first temperature control judgment unit 53 calculates a charging gain amount _GB indicating an increase in the amount of charging power due to the execution of pre-temperature control (531), calculates a temperature control power consumption amount ΔE _{b_temc} indicating the amount of power consumed by the execution of pre-temperature control (532), and determines that pre-temperature control should be executed if the charging gain amount _GB exceeds the temperature control power consumption amount ΔE _{b_temc} (533, 534).

[Second embodiment]
The second embodiment will be described below, in which the same elements as those in the previous embodiment are given the same reference numerals and the description thereof will be omitted.

Figure 9 is a flowchart showing the overall process of the battery temperature control method according to this embodiment. Note that in Figure 9, some of the processes common to Figure 3 are omitted in order to simplify the drawing.

As shown in the figure, in this embodiment, in addition to the first temperature control judgment, a second temperature control judgment (S450) is executed, and if the results of both the first temperature control judgment and the second temperature control judgment are positive, pre-temperature control is executed, and if either is negative, the process ends without executing pre-temperature control (S500, S550, S600).

Figure 10A is a flowchart explaining the details of the second temperature control determination. Also, Figure 10B is a block diagram showing the detailed configuration of the second temperature control determination unit 54.

As shown in the figure, in the second temperature adjustment judgment, first, the current battery temperature T _{B_c} and the charging target temperature T _{B_t} are input, and the required temperature adjustment time Δt _req is calculated (S451, required temperature adjustment time calculation unit 541).

More specifically, when the current battery temperature T _{B_c} is higher than the charging target temperature T _{B_t} , the temperature adjustment required time calculation unit 541 calculates the cooling amount (hereinafter referred to as the "required cooling amount") required to lower the current battery temperature T _B to the charging target temperature T _{B_t} as the above-mentioned required temperature adjustment amount. Furthermore, the temperature adjustment required time Δt req is obtained by dividing the required cooling amount by the cooling amount (chiller cooling amount or radiator cooling amount) corresponding to the cooling method (cooling by operating the chiller 301 or cooling using the radiator 305) selected by the logic shown in Fig. ₆ from the required cooling amount.

In particular, the required cooling amount can be calculated by multiplying the difference between the current battery temperature T _{B_c} and the charging target temperature T _{B_t} by the known battery heat capacity (thermal mass cooling amount) and adding the total heat generation amount _Qb of the battery during driving.

On the other hand, when the current battery temperature T _{B_c} is lower than the charging target temperature T _{B_t} , the amount of heat required to raise the current battery temperature T _B to the charging target temperature T _{B_t} (hereinafter referred to as the "required warm-up amount") is calculated as the required temperature adjustment amount. Furthermore, the required temperature adjustment time Δt _req is calculated by dividing the required warm-up amount by the unit heating amount (PTC warm-up amount) corresponding to the output of the PTC heater 304.

In particular, the required warm-up amount can be calculated by multiplying the difference between the current battery temperature T _{B_c} and the charging target temperature T _{B_t} by the known battery heat capacity (thermal mass cooling amount) and subtracting the total heat generation amount Q _b of the battery during driving.

Then, the estimated travel time Δt _tra required for traveling from the current location to the charging facility is acquired, and it is determined whether the temperature control required time Δt _req calculated by the above logic operation is equal to or longer than the estimated travel time Δt _tra (S452, S453). If the temperature control required time Δt _req is equal to or longer than the estimated travel time Δt _tra , the second temperature control determination flag _f2 is set to ON, and if not, the second temperature control determination flag _f2 is set to OFF (S454, S455, subtraction unit 542, second temperature control determination flag setting unit 543).

The following describes the control results of the battery temperature control method of this embodiment.

Fig. 11 is a timing chart showing an example of the control result by the battery temperature control method of this embodiment. In Fig. 11, a warm-up scene for lowering the battery temperature T _B to the charging target temperature T _{B_t} is assumed as the pre-temperature control. For the sake of simplicity, it is assumed that the first temperature control flag f ₁ is ON at the timing when the second temperature control flag f ₂ is ON.

As shown in the figure, at time t11 when the preliminary judgment flag _fp switches from OFF to ON, the second temperature control judgment is started in parallel with the first temperature control judgment. After time t11, the current battery temperature T _{B_c} rises over time due to power consumption during traveling. Meanwhile, the temperature control required time Δt _req gradually decreases with the rise in the current battery temperature T _{B_c} . Furthermore, since the electric vehicle travels toward the charging facility, the predicted travel time Δt _tra also decreases over time.

Here, at time t11 when the preliminary judgment flag _fp is switched to ON, the predicted travel time Δt _tra is greater than the required temperature adjustment time Δt _req . On the other hand, the decrease in the predicted travel time Δt _tra is greater than the decrease in the required temperature adjustment time Δt _req , and the magnitude relationship between the predicted travel time Δt _tra and the required temperature adjustment time Δt _req is reversed at time t12. Therefore, at time t12, the second temperature adjustment judgment flag _f2 is switched from OFF to ON. Therefore, pre-temperature adjustment control (S600), more specifically, warming up the battery 34, is started from time t12. At the same time, the end judgment (S700) is also started.

Thereafter, at time t13 when the end determination flag _ff is switched from OFF to ON based on the logic of the end determination (S700), the pre-temperature adjustment control ends.

In the battery temperature control method of this embodiment described above, when the external charging request signal _Sc is acquired, a second temperature control determination (S450) is made to determine whether or not to execute pre-temperature control, separately from the first temperature control determination (S400). If the results of the first temperature control determination and the second temperature control determination are positive, the pre-temperature control is executed.

In particular, in the second temperature control judgment, a required temperature control time Δt _req , which is determined as the time required from the start to the end of pre-temperature control, is calculated (S451), and a predicted travel time Δt _tra required from the current location of the electric vehicle to the charging equipment for external charging is obtained (S452). Then, when the required temperature control time Δt _req exceeds the predicted travel time Δt _tra , it is determined that pre-temperature control should be performed (S453, S454, S455).

This allows the time spent performing pre-temperature control to be kept to a minimum. Therefore, when pre-temperature control is interrupted for reasons such as the cancellation of an external charging request, energy loss occurs for the amount of energy that had been spent performing pre-temperature control up until that point, but by keeping the time spent performing pre-temperature control to a minimum, this energy loss can be minimized.

In addition, in the judgment shown in S602 of Fig. 6 (judgment on whether to operate the chiller 301) based on the configuration of the second embodiment, instead of or in addition to the judgment described in the first embodiment, a judgment logic based on the magnitude relationship between the temperature adjustment required time Δt _req and the predicted travel time Δt _tra may be adopted. More specifically, a judgment logic may be adopted in which cooling by the chiller 301 is not performed when the temperature adjustment required time Δt _req is equal to or less than the predicted travel time Δt _tra , and the chiller 301 is operated to perform cooling when the temperature adjustment required time Δt _req exceeds the predicted travel time Δt _tra . This judgment logic allows the execution of the pre-temperature adjustment control and the operation of the chiller 301 to be performed at substantially the same judgment (timing), so that the cooling of the battery 34 in the pre-temperature adjustment control can be performed more efficiently.

The above describes the embodiments of the present invention, but the configurations described in the above embodiments and each modified example are merely examples of application of the present invention and are not intended to limit the technical scope of the present invention.

REFERENCE SIGNS LIST 1 vehicle system 20 navigation system 30 temperature control system 34 battery 36 temperature control actuator 50 controller
51 Temperature control determination unit 52 Preliminary determination unit 53 First temperature control determination unit 54 Second temperature control determination unit 55 Pre-temperature control unit 56 End determination unit

Claims (7)

When an external charging request signal indicating a request to execute external charging of a battery mounted in an electric vehicle is received, a first temperature control determination is performed to determine whether or not to execute a pre-temperature control for warming up or cooling the battery;
If the result of the first temperature adjustment determination is positive, the pre-temperature adjustment control is executed;
In the first temperature control determination,
A charging gain amount indicating an increase in the amount of charging power due to the execution of the pre-temperature adjustment control is calculated.
A temperature control power consumption amount indicating the amount of power consumed by the execution of the pre-temperature control is calculated;
determining that the pre-temperature adjustment control should be performed when the charging gain amount exceeds the temperature adjustment power consumption amount;
Battery temperature control method. The battery temperature control method according to claim 1,
When the external charging request signal is acquired, a preliminary determination is further performed to determine whether or not the first temperature adjustment determination is to be performed;
If the result of the preliminary determination is positive, the first temperature control determination is executed;
In the preliminary determination,
Calculate a target charging temperature that the battery temperature should reach during charging;
Calculate an estimated charging temperature, which is an estimated battery temperature during charging;
Calculating an estimated temperature difference given as a difference between the estimated charging temperature and the target charging temperature;
When the estimated temperature difference exceeds a predetermined threshold temperature difference, it is determined that the first temperature adjustment determination should be performed.
Battery temperature control method. The battery temperature control method according to claim 2,
In the first temperature control determination,
Calculating a first estimated amount of charging energy, which is an estimated amount of charging energy assuming that the pre-temperature adjustment control is not executed, based on the estimated temperature during charging;
Calculating a second estimated amount of charging energy, which is an estimated amount of charging energy when the pre-temperature adjustment control is performed, based on the charging target temperature;
Calculating the charging gain amount based on a difference between the first estimated charging energy amount and the second estimated charging energy amount.
Battery temperature control method. The battery temperature control method according to claim 2,
During the execution of the pre-temperature adjustment control, an end determination is performed to determine whether or not to end the pre-temperature adjustment control;
If the result of the termination determination is affirmative, the pre-temperature adjustment control is terminated.
In the end determination,
When the estimated temperature difference falls below the threshold temperature difference or the charging gain amount falls below the temperature adjustment power consumption amount, it is determined that the pre-temperature adjustment control should be terminated.
Battery temperature control method. The battery temperature control method according to claim 3,
In the pre-temperature control,
When the estimated charging temperature is lower than the target charging temperature, the battery is warmed up;
When the estimated charging temperature is higher than the target charging temperature, the battery is cooled.
Battery temperature control method. A battery temperature control method according to any one of claims 1 to 5,
When the external charging request signal is acquired, a second temperature control determination is performed to determine whether or not to execute the pre-temperature control, separately from the first temperature control determination.
When the results of both the first temperature adjustment determination and the second temperature adjustment determination are positive, the pre-temperature adjustment control is executed;
In the second temperature control determination,
A required temperature control time is calculated as the time required from the start to the end of the pre-temperature control.
acquiring a travel time required from a current location of the electric vehicle to a charging facility that performs the external charging;
When the temperature adjustment required time exceeds the movement time, it is determined that the pre-temperature adjustment control should be performed.
Battery temperature control method. a first temperature control determination unit that, when receiving an external charging request signal indicating a request to execute external charging of a battery mounted in an electric vehicle, determines whether to execute a pre-temperature control to warm up or cool the battery;
and a pre-temperature adjustment control unit that executes the pre-temperature adjustment control when the determination result is positive.
The first temperature control determination unit is
A charging gain amount indicating an increase in charging power due to the execution of the pre-temperature adjustment control is calculated;
A temperature control power consumption amount indicating the amount of power consumed by the execution of the pre-temperature control is calculated;
determining that the pre-temperature adjustment control should be performed when the charging gain amount exceeds the temperature adjustment power consumption amount;
Battery temperature control device.

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