Battery temperature management method and battery temperature management device

Abstract

The present invention acquires the temperature of a battery installed in an electric vehicle, and keeps the temperature of the battery at or below a predetermined threshold by cooling the battery when the temperature of the battery is at or above the threshold. The present invention determines whether a current destination of the electric vehicle is a specific destination where the vehicle is expected to remain stopped for a prescribed time or longer, and lowers the threshold when the current destination is the specific destination.

Description

Battery temperature management method and battery temperature management device

[0001] The present invention relates to a battery temperature management method and a battery temperature management device for managing the temperature of a battery mounted on an electric vehicle.

[0002] JP2019-170028A discloses a battery cooling control device that predicts the remaining power of a battery when the vehicle reaches a destination, calculates the cooling usable power that can be used to cool the battery based on the predicted remaining power, and cools the battery using this cooling usable power while traveling to the destination.

[0003] Batteries are used within an appropriate temperature range to prevent rapid deterioration or damage. Therefore, even if a battery is repeatedly used in a manner that keeps the battery temperature relatively high for a long period of time, as long as the temperature is within the appropriate temperature range, there will be no noticeable deterioration of the battery in the short term. However, if the battery is repeatedly used in a manner that keeps the battery temperature relatively high for a long period of time, there is a problem in that battery deterioration will be accelerated in the long term, even if the temperature is within the appropriate temperature range.

[0004] Therefore, in order to suppress deterioration from a long-term perspective, it is preferable to slightly overcool the battery so that a lower temperature is maintained within the appropriate temperature range. On the other hand, if the situation in which the battery temperature is maintained does not continue for a long time after the battery is slightly overcooled, such slightly overcooling has the disadvantage of simply worsening the fuel economy and reducing the cruising range of the electric vehicle. Therefore, such slightly overcooling should not be performed all the time, and it is desirable to perform it only when a situation in which the battery temperature remains relatively high for a long time is identified.

[0005] The present invention aims to provide a battery temperature management method and device that can suppress battery deterioration from a long-term perspective by determining situations in which the battery temperature remains relatively high for a long period of time and cooling the battery accordingly.

[0006] One aspect of the present invention is a battery temperature management method that acquires the temperature of a battery mounted on an electric vehicle, and when the battery temperature is equal to or higher than a predetermined threshold, cools the battery to maintain the battery temperature at or below the threshold. This battery temperature management method determines whether the current destination of the electric vehicle is a specific destination where the electric vehicle is expected to be stopped continuously for a predetermined time or more, and when the current destination is the specific destination, lowers the threshold.

[0007] FIG. 1 is a block diagram showing a schematic configuration of an electric vehicle. FIG. 2 is an explanatory diagram showing the configuration of a cooling system. FIG. 3 is an explanatory diagram showing another configuration of a cooling system. FIG. 4 is a block diagram showing the configuration of a controller. FIG. 5 is a flowchart related to battery temperature management control. FIG. 6 is a flowchart related to destination determination. FIG. 7 is another flowchart related to destination determination. FIG. 8 is another flowchart related to destination determination. FIG. 9 is a flowchart related to switching of the cooling circuit. FIG. 10 is a graph schematically showing changes in battery temperature, etc.

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0009] 1 is a block diagram showing a schematic configuration of an electric vehicle 100. The electric vehicle 100 is a vehicle that generates all or part of its driving force using electric power. Specifically, the electric vehicle 100 is, for example, an electric vehicle or a hybrid vehicle.

[0010] As shown in FIG. 1 , the electric vehicle 100 includes an electric powertrain 10 , a battery 11 , a cooling system 12 , a navigation system 13 , and a controller 14 .

[0011] The electric powertrain 10 is a power source for the electric vehicle 100. The electric powertrain 10 is configured by, for example, an electric motor, an inverter, a reducer, etc. Here, the electric motor, etc. are not shown in the drawings.

[0012] The battery 11 supplies necessary electric power to the electric powertrain 10 and other components of the electric vehicle 100. The battery 11 is rechargeable. Specifically, the battery 11 is, for example, a lithium-ion battery.

[0013] The battery 11 deteriorates (deteriorates over time) due to repeated discharge and charging. ｂａｔ The performance of the battery 11 also deteriorates when the battery 11 is used in a state where the battery temperature T ｂａｔ The battery 11 is managed to maintain a temperature within a predetermined appropriate temperature range at least during use. That is, the battery 11 is cooled or heated as needed so that it is used within the appropriate temperature range. Typically, the appropriate temperature range for the battery 11 is, for example, a range from about 0°C to about 45°C. Also, typically, the optimum battery temperature T ｂａｔ is about 20°C to about 30°C.

[0014] Battery temperature T ｂａｔ If the battery temperature T is managed within this appropriate temperature range, the battery 11 is unlikely to deteriorate in principle. In other words, if the battery 11 is used within the appropriate temperature range, deterioration of the battery 11 will not be accelerated, at least in the short term. However, if the battery temperature T ｂａｔ Even if the battery temperature T ｂａｔ If the battery 11 is repeatedly used in such a manner that the battery temperature T is higher than the optimum temperature (for example, about 20 to 30°C) and remains close to the upper limit (for example, about 45°C) for a long period of time, the battery 11 may deteriorate over the long term. ｂａｔ However, a relatively high temperature within the appropriate temperature range is sometimes referred to as a high temperature for convenience.

[0015] The cooling system 12 is a system that cools heat-generating parts of the electric vehicle 100. In this embodiment, the cooling system 12 cools the electric powertrain 10 and the battery 11. A specific configuration of the cooling system 12 will be described later.

[0016] The navigation system 13 is a system that provides information such as a driving route to a destination set by the driver in advance and an estimated time of arrival (required time) to the destination. The navigation system 13 acquires the current location of the electric vehicle 100 using a GPS (Global Positioning System) receiver (not shown) or the like. The navigation system 13 then provides the driver or other users (hereinafter referred to as the driver, etc.) with information related to the driving route and estimated time of arrival using location information of the current location, map data 16, registered destinations 17, and driving history 18, etc.

[0017] The map data 16 is a collection of information related to the road network, topography, and attributes of facilities, etc. The attributes of facilities, etc. are information that indicates the name of the facility, etc., and the business content of the facility, etc. (for example, restaurant, accommodation facility, amusement facility, museum, etc.).

[0018] The registered destination 17 is information that indicates the location (position) of a destination or its candidate destination (hereinafter referred to as a registered destination) that is registered in the navigation system 13. The registered destination 17 is set in advance by the driver or other users. A plurality of registered destinations 17 can be registered in the navigation system 13. The registered destination 17 includes at least information related to the location, i.e., coordinates on a map, and may also be assigned attributes (or labels representing the attributes). Specifically, these are "home" and "workplace (place of work)." In this embodiment, it is assumed that at least "home" and "workplace" are set in the navigation system 13 as registered destinations 17.

[0019] The traveling history 18 is data that stores information such as routes that the electric vehicle 100 has actually traveled in the past. The traveling history 18 is data that associates, for example, a destination, a traveling route, a time or time zone when the electric vehicle departed for the destination (departure time or departure time zone), a time or time zone when the electric vehicle traveled (travel time or travel time zone), a date, a day of the week, a time or time zone when the electric vehicle arrived at the destination (arrival time or arrival time zone), and a stopping time at the destination. In the present embodiment, the traveling history 18 includes information such as the destination, the traveling route, the departure time zone, the date, the day of the week, the arrival time zone, and the stopping time.

[0020] The "departure time zone" in the driving history 18 is information that indicates the time zone to which the electric vehicle 100 started traveling toward the destination belongs. The "date" and "day of the week" in the driving history 18 are information for distinguishing between weekdays and holidays (public holidays). The "arrival time zone" in the driving history 18 is information that indicates the time zone to which the time of arrival at the destination belongs. The arrival time zone is categorized in the same way as the departure time zone. The "stopping time" in the driving history 18 is recorded, for example, by measuring the time from when the power switch (ignition switch) is turned off at the destination to when the power switch is next turned on.

[0021] The time periods for departure and arrival times are divided into, for example, pre-dawn (0:00-3:00), dawn (3:00-6:00), morning (6:00-9:00), before noon (9:00-12:00), late afternoon (12:00-15:00), evening (15:00-18:00), early evening (18:00-21:00), and late evening (21:00-24:00).

[0022] The controller 14 is a control device that comprehensively controls each part of the electric vehicle 100. The controller 14 is configured by, for example, one or more computers.

[0023] In this embodiment, the controller 14 appropriately cools the battery 11 using the cooling system 12 to control the battery temperature T ｂａｔThe controller 14 functions as a battery temperature management device that manages the temperature of the battery 11 so that the temperature of the battery 11 is maintained at least within an appropriate temperature range. The program that causes the controller 14 to function as a battery temperature management device is a battery temperature management program. Hereinafter, the control by the controller 14 to manage the temperature of the battery 11 will be referred to as battery temperature management control.

[0024] The controller 14 detects the battery temperature T ｂａｔ , the state of charge (SOC) of the battery 11, and the outside temperature T ａｔｍ The temperatures of various coolants, etc., and other parameters required for battery temperature management control can be appropriately acquired (calculated) using sensors (not shown). The controller 14 may also use the current date and time (current month and day, day of the week, time, etc.) in the battery temperature management control. In this embodiment, the current date and time is updated and managed by the controller 14 itself, and is known to the controller 14.

[0025] The controller 14, which is a battery temperature management device, detects the battery temperature T ｂａｔ A threshold value Th is set for the battery temperature T ｂａｔ When the battery temperature T exceeds the threshold value Th, the cooling system 12 is used to cool the battery 11. ｂａｔ is maintained below a threshold value Th.

[0026] In principle, the threshold value Th is set to the upper limit of the appropriate temperature range of the battery 11 or a temperature lower than the upper limit. ｂａｔ The battery 11 is cooled so that the temperature is maintained within an appropriate temperature range.

[0027] However, in this embodiment, the threshold value Th is variable. Specifically, the controller 14 may lower the threshold value Th depending on the current destination of the electric vehicle 100. When the threshold value Th is lowered, the controller 14 may adjust the battery temperature T ｂａｔ The battery 11 is cooled until the battery temperature is lower than the

[0028] In the following, the battery temperature T ｂａｔ The normal (standard) threshold Th set for Ｈ The threshold Th lowered according to the current destination is called a low threshold Th (first threshold). Ｌ Therefore, the upper limit of the appropriate temperature range of the battery 11 is set to T ＵＬ , the lower limit is T ＬＬ If so, T ＵＬ >Th Ｈ >Th Ｌ >T ＬＬ is.

[0029] As described above, the threshold value Th is lowered, and the battery temperature T ｂａｔ is the low threshold Th Ｌ The control of cooling the battery 11 so as to maintain the battery temperature at or below this temperature is performed preventively in order to suppress deterioration of the battery 11 from a long-term perspective. Ｈ to low threshold Th Ｌ Cooling the battery 11 by lowering the temperature to 0°C is called deterioration prevention cooling.

[0030] The controller 14 can set the threshold value Th substantially individually depending on the characteristics (attributes) of the specific current destination. That is, the controller 14 can set a different low threshold value Th for each destination. Ｌ However, in this embodiment, for the sake of simplicity, the battery temperature T ｂａｔ The threshold Th for Ｈ or low threshold Th Ｌ That is, in this embodiment, the controller 14 sets the high threshold Th Ｈ or low threshold Th Ｌ The threshold value Th is selected from the two values.

[0031] Fig. 2 is an explanatory diagram showing the configuration of the cooling system 12. As shown in Fig. 2, the cooling system 12 includes two cooling circuits, for example, a first cooling circuit 21 and a second cooling circuit 22, as cooling circuits for cooling the battery 11.

[0032] The first cooling circuit 21 is a battery cooling circuit that cools the battery 11 by circulating coolant or other coolant (hereinafter simply referred to as coolant) between the battery 11 and the radiator 31. In this embodiment, the first cooling circuit 21 also serves as an electric powertrain cooling circuit that cools the electric powertrain 10 by circulating coolant between the electric powertrain 10 and the radiator 31. However, the controller 14 can control valves (not shown) and the like to cause the first cooling circuit 21 to circulate coolant only through the battery 11 or only through the electric powertrain 10. In other words, the first cooling circuit 21 can cool the battery 11, the electric powertrain 10, or both, as needed.

[0033] Specifically, the first cooling circuit 21 includes a radiator 31 , a first cooling water passage 32 , and a pump 33 .

[0034] The radiator 31 cools the coolant (hereinafter referred to as first coolant) flowing through the first cooling water passage 32 by airflow 34 (outside air). The first cooling water passage 32 is configured to circulate the first coolant through the radiator 31, the electric powertrain 10, and the battery 11. The pump 33 pumps the first coolant through the first cooling water passage 32. The pump 33 is driven by the power of the battery 11, but its power consumption is minimal. Therefore, when the battery 11 is cooled using the first cooling circuit 21, the SOC of the battery 11 is hardly reduced by this cooling.

[0035] The second cooling circuit 22 is a battery cooling circuit that cools the battery 11 using an air conditioning (HVAC: Heating, Ventilation, and Air Conditioning) system 41. Specifically, the second cooling circuit 22 includes the air conditioning system 41, a chiller 42, a second cooling water passage 43, and a pump 44.

[0036] The air conditioning system 41 adjusts the temperature of the vehicle interior by repeatedly compressing and expanding a refrigerant. The air conditioning system 41 includes a refrigerant circulation path 45 for circulating the refrigerant, a compressor 46 for compressing the refrigerant, and an expansion valve (not shown) for expanding the refrigerant.

[0037] The chiller 42 is a heat exchanger additionally provided in the refrigerant circulation path 45 of the air conditioning system 41 so that the air conditioning system 41 can be used to cool the battery 11. The chiller 42 cools the coolant or other cooling liquid (hereinafter referred to as second coolant) flowing in the second cooling water path 43 using the refrigerant of the air conditioning system 41. The second cooling water path 43 circulates the second coolant between the battery 11 and the chiller 42. The pump 44 pumps the second coolant through the second cooling water path 43.

[0038] Therefore, the second cooling circuit 22 is a battery cooling circuit that cools the battery 11 by circulating coolant between the battery 11 and a chiller 42 that is cooled by the refrigerant of the air conditioning system 41 .

[0039] The pump 44 is driven by the power of the battery 11, but its power consumption is small. The compressor 46 is also driven by the power of the battery 11, but its power consumption is significantly greater than the power consumption of the pump 33 and the pump 44. Therefore, the battery cooling capacity of the second cooling circuit 22 is higher than that of the first cooling circuit 21, but the power consumption of the second cooling circuit 22 is greater than that of the first cooling circuit 21. Therefore, in this embodiment, in situations where the power (SOC) of the battery 11 should be actively consumed, the battery 11 is cooled using the second cooling circuit 22. On the other hand, in situations where the power (SOC) of the battery 11 does not need to be consumed, the battery 11 is cooled using the first cooling circuit 21 as a general rule.

[0040] The first cooling circuit 21 and the second cooling circuit 22 can be used together. Therefore, in a situation where the battery 11 needs to be cooled rapidly while actively consuming the power (SOC) of the battery 11, the battery 11 may be cooled using both the first cooling circuit 21 and the second cooling circuit 22.

[0041] In addition, the first cooling water passage 32 of the first cooling circuit 21 and the second cooling water passage 43 of the second cooling circuit 22 may be connected using a valve and water passage (not shown) as necessary. For example, when the electric powertrain 10 is cooled using an air conditioning system 41, the first cooling water passage 32 and the second cooling water passage 43 are connected. The connection or disconnection of the first cooling water passage 32 and the second cooling water passage 43 is appropriately controlled by the controller 14. In this embodiment, for simplicity, it is assumed that the first cooling water passage 32 and the second cooling water passage 43 are separated (disconnected).

[0042] In this embodiment, as described above, the cooling system 12 includes a first cooling circuit 21 that cools the battery 11 using a radiator 31 and a second cooling circuit 22 that cools the battery 11 using an air conditioning system 41, but is not limited to this.

[0043] 3 is an explanatory diagram showing another configuration of the cooling system 12. As shown in FIG. 3, the cooling system 12 may be configured with a first cooling circuit 21 that cools the battery 11 using a radiator 31, and a third cooling circuit 23 that cools the battery 11 using a blower fan 47. The blower fan 47 cools the battery 11 by sending running wind 34 (outside air) to the battery 11. In this case, the blower fan 47 and a flow passage for the wind (air) sent by the blower fan 47 configure the third cooling circuit 23.

[0044] The blower fan 47 is driven by the power of the battery 11, but its power consumption is small. Therefore, when the battery 11 is cooled by the third cooling circuit 23, there is almost no decrease in the SOC of the battery 11. Furthermore, the first cooling circuit 21 and the third cooling circuit 23 can be used together.

[0045] Alternatively, the cooling system 12 may be configured to omit the blower fan 47 and have the traveling wind 34 (outside air) directly blown into the battery 11. In this case, the flow passage of the traveling wind 34 constitutes the third cooling circuit 23. The cooling system 12 may also include all of the first cooling circuit 21, the second cooling circuit 22, and the third cooling circuit 23. The first cooling circuit 21 and the second cooling circuit 22 are water-cooled cooling circuits that circulate coolant through the battery 11, and the third cooling circuit 23 is an air-cooled cooling circuit that blows air into the battery 11. Therefore, the deterioration preventive cooling of this embodiment can be implemented using a water-cooling system, an air-cooling system, or both.

[0046] In the following description, unless otherwise specified, the cooling system 12 is assumed to be composed of a first cooling circuit 21 and a second cooling circuit 22 as shown in FIG.

[0047] 4 is a block diagram showing the configuration of the controller 14. Here, the functional configuration of the controller 14 will be described, particularly the portion that constitutes the battery temperature management device. As shown in FIG. 4, the controller 14 includes a destination determination unit 51, a threshold setting unit 52, and a temperature management unit 53.

[0048] The destination determination unit 51 determines whether the current destination of the electric vehicle 100 is a specific destination.

[0049] The destination determination unit 51 acquires the current destination using the navigation system 13. Specifically, when the driver or the like sets a destination in the navigation system 13, the destination determination unit 51 acquires information related to the destination set in the navigation system 13 and sets this as the current destination.

[0050] On the other hand, when the driver or the like has not set a destination in the navigation system 13, the destination determination unit 51 can estimate the current destination. Specifically, when a destination has not been set in the navigation system 13, the destination determination unit 51 acquires the current driving route of the electric vehicle 100, the driving history 18, and the like from the navigation system 13. The destination determination unit 51 then compares the current driving route and the current date and time with the driving history 18. If, as a result of this comparison, there is driving history 18 that corresponds to the current driving route and the current date and time, the destination in the driving history 18 is estimated to be the current destination. The current driving route is information that identifies the current location of the electric vehicle 100 or the road on which the electric vehicle 100 is currently traveling.

[0051] In this embodiment, for simplicity, it is assumed that the driver or the like sets the destination in the navigation system 13. The driver or the like can set the destination by, for example, selecting from one or more registered destinations 17 set in advance in the navigation system 13. Furthermore, when the destination is a point that is not set as a registered destination 17, the driver or the like can set the destination by touching the map on the display screen (not shown) of the navigation system 13 or by searching for an address, facility name, or the like.

[0052] A specific destination is a destination where the vehicle is expected to stop (park) for a predetermined time or more after arrival. In other words, a specific destination is a destination where there is a high probability that the battery 11 will be left in a high temperature state (a relatively high temperature state within an appropriate temperature range) for a long time when the vehicle arrives, and therefore, where deterioration preventive cooling should be performed. Therefore, the predetermined time here is a time period during which deterioration of the battery 11 will be accelerated if the high temperature state of the battery 11 continues. This predetermined time is determined in advance based on experiments or simulations and in accordance with the specific characteristics of the battery 11. The predetermined time is typically about 4 to 6 hours.

[0053] The destination determination unit 51 determines whether the current destination is a specific destination (hereinafter referred to as destination determination) based on the attributes (labels) of the registered destinations 17 or the driving history 18. A specific method for determining the destination will be described in detail later.

[0054] The threshold setting unit 52 determines the battery temperature T ｂａｔ Specifically, when it is determined in the destination determination that the current destination is not a specific destination but a general destination (hereinafter referred to as a general destination), the threshold setting unit 52 sets or changes the threshold value Th for the battery temperature T ｂａｔ The threshold value Th for Ｈ On the other hand, when it is determined in the destination determination that the current destination is a specific destination, the threshold setting unit 52 sets the battery temperature T ｂａｔ The threshold value Th for Ｌ The default value of the threshold value Th is the high threshold value Th. Ｈ is.

[0055] Furthermore, the threshold setting unit 52 determines whether to set or change the threshold value Th in accordance with the result of the destination determination based on the remaining distance to the current destination, the remaining time to the current destination, or both. That is, the threshold setting unit 52 determines the timing to lower the threshold value Th in accordance with the result of the destination determination based on the remaining distance to the current destination or the remaining time to the current destination.

[0056] Specifically, the threshold setting unit 52 determines whether the distance (remaining distance) from the current location to the current destination along the current travel route is equal to or shorter than a predetermined distance. If the remaining distance is longer than the predetermined distance, the threshold setting unit 52 determines whether the battery temperature T ｂａｔ The threshold value Th for Ｈ After that, when the remaining distance becomes equal to or less than the predetermined distance, the threshold setting unit 52 sets the battery temperature T ｂａｔ The threshold value Th for the destination is set or changed depending on the result of the destination determination.

[0057] The threshold setting unit 52 also determines whether the time (remaining time) until the vehicle reaches the current destination from the current location along the current travel route is equal to or less than a predetermined time. If the remaining time is longer than the predetermined time, the threshold setting unit 52 determines whether the battery temperature T ｂａｔ The threshold value Th for Ｈ After that, when the remaining time becomes equal to or less than the predetermined time, the threshold setting unit 52 sets the battery temperature T ｂａｔ The threshold value Th for the destination is set or changed depending on the result of the destination determination.

[0058] In this embodiment, when at least one of the conditions relating to the remaining distance or the remaining time is satisfied, the threshold setting unit 52 sets the battery temperature T ｂａｔ The threshold value Th for the destination is set or changed depending on the result of the destination determination.

[0059] The above-mentioned "predetermined distance" is the distance that the battery temperature T ｂａｔ is the low threshold Th Ｌ The above-mentioned "predetermined time" is determined in advance based on the heat capacity of the battery 11 and the cooling capacity of the cooling system 12, as follows: ｂａｔ is the low threshold Th Ｌ As shown below, the "predetermined distance" and the "predetermined time" are determined in advance based on the heat capacity of the battery 11 and the cooling capacity of the cooling system 12 for the battery 11. In this embodiment, the "predetermined distance" and the "predetermined time" are set in advance based on experiments, simulations, or the like.

[0060] The cooling capacity of the battery 11 by the cooling system 12 differs depending on, for example, when deterioration prevention cooling is performed using the first cooling circuit 21, when deterioration prevention cooling is performed using the second cooling circuit 22, or when deterioration prevention cooling is performed using both the first cooling circuit 21 and the second cooling circuit 22. Therefore, the above-mentioned "predetermined distance" and "predetermined time" may be changed depending on the specific cooling circuit configuration used for deterioration prevention cooling.

[0061] The temperature management unit 53 monitors the battery temperature T ｂａｔ In this embodiment, the temperature management unit 53 manages the temperature of the battery 11 so that the battery temperature T ｂａｔ When the threshold value Th is equal to or greater than the high threshold value Th, the cooling system 12 cools the battery 11. Ｈ When the battery temperature T ｂａｔ The battery 11 is cooled appropriately so that the temperature is maintained within the appropriate temperature range. Ｌ When the battery temperature T ｂａｔ is the low threshold Th Ｌ Preventive cooling is performed to maintain the following temperatures.

[0062] In principle, the temperature management unit 53 ａｔｍ and the temperature of the first cooling water (hereinafter referred to as the first cooling water temperature T ｗ１ The cooling circuit used to cool the battery 11 is switched depending on the magnitude relationship between the two values.

[0063] Specifically, the outside temperature T ａｔｍ is the first cooling water temperature T ｗ１ When the temperature is lower than 100°C and the first cooling circuit 21 using the radiator 31 has a cooling capacity, the temperature management unit 53 cools the battery 11 by the first cooling circuit 21 in principle.

[0064] On the other hand, the outside temperature T ａｔｍ is the first cooling water temperature T ｗ１ When the temperature is above this level, the first cooling water cannot be cooled by the running wind 34 (outside air). In other words, the cooling capacity of the first cooling circuit 21 is substantially lost. ａｔｍ is the first cooling water temperature T ｗ１ In the above cases, when the battery 11 needs to be cooled, the temperature management unit 53 cools the battery 11 using the second cooling circuit 22 .

[0065] In addition, the threshold value Th is a low threshold value Th ＬWhen the temperature is lowered to 0 and deterioration prevention cooling is performed, the temperature management unit 53 further switches the cooling circuit used to cool the battery 11 according to the SOC of the battery 11 .

[0066] Specifically, the temperature management unit 53 sets an upper limit value U ｌｉｍ Then, the SOC of the battery 11 is set to the upper limit value U ｌｉｍ If the temperature is below 100°C, the temperature management unit 53 cools the battery 11 by the first cooling circuit 21 using the radiator 31. As a result, the temperature management unit 53 performs deterioration prevention cooling without consuming much of the battery 11's power.

[0067] On the other hand, when the SOC of the battery 11 reaches the upper limit U ｌｉｍ If the temperature is higher than , the temperature management unit 53 cools the battery 11 by the second cooling circuit 22 that uses the air conditioning system 41. In this way, the temperature management unit 53 actively uses the power of the battery 11 to perform deterioration prevention cooling.

[0068] When the battery 11 is maintained in a high temperature state (a relatively high temperature state within an appropriate temperature range), a high SOC is likely to accelerate deterioration of the battery 11. Therefore, in a situation where deterioration preventive cooling is required, when the SOC of the battery 11 is high, by actively using the power of the battery 11 using the second cooling circuit 22 as described above, deterioration of the battery 11 is likely to be particularly suppressed from a long-term perspective.

[0069] The upper limit value U for SOC ｌｉｍ is set in advance according to the specific characteristics of the battery 11. In this embodiment, the upper limit value U ｌｉｍ is set in advance based on experiments or simulations.

[0070] 5 is a flowchart related to the battery temperature management control. As shown in FIG. 5, in step S10, the destination determination unit 51 acquires the current destination. In step S11, the destination determination unit 51 performs destination determination. That is, it is determined whether the current destination is a specific destination.

[0071] In step S11, if it is determined that the current destination is not a specific destination but a general destination, the process proceeds to step S12. In step S12, the threshold setting unit 52 sets the battery temperature T ｂａｔ The threshold value Th for Ｈ Set to.

[0072] On the other hand, if it is determined in step S11 that the current destination is a specific destination, the process proceeds to step S13. In step S13, the threshold setting unit 52 determines whether the distance to the current destination is less than a predetermined distance. If it is determined in step S13 that the distance to the current destination is longer than the predetermined distance, the process proceeds to step S14, where the threshold setting unit 52 determines whether the current destination will be reached in less than a predetermined time. If it is determined in step S14 that it will take longer than the predetermined time to reach the current destination, the process proceeds to step S12, where the threshold setting unit 52 determines whether the battery temperature T ｂａｔ The threshold value Th for Ｈ That is, even if the current destination is a specific destination, when the remaining distance to the current destination is longer than a predetermined distance and the remaining time to the current destination is longer than a predetermined time, the threshold setting unit 52 sets the threshold Th to the default high threshold Th. Ｈ Set to.

[0073] In step S13, when it is determined that the distance to the current destination is equal to or shorter than the predetermined distance, the process proceeds to step S15, and the threshold value setting unit 52 sets the battery temperature T ｂａｔ The threshold value Th for Ｌ Also, when it is determined in step S14 that the time remaining until arrival at the current destination is equal to or less than the predetermined time, the process proceeds to step S15, and the threshold setting unit 52 sets the battery temperature T ｂａｔ The threshold value Th for Ｌ That is, if the current destination is a specific destination (S11: YES), and further, when the distance to the current destination is less than a predetermined distance (S13: YES), or when the time to the current destination is less than a predetermined time, the threshold setting unit 52 sets the battery temperature T ｂａｔ The threshold value Th forＬ Set to.

[0074] As described above, in step S12, the threshold value Th is set to the high threshold value Th. Ｈ or in step S15, the threshold value Th is set (maintained) to the low threshold value Th Ｌ When the battery temperature T ｂａｔ By comparing the battery temperature T ｂａｔ Then, the battery temperature T ｂａｔ If the threshold value Th exceeds the high threshold value Th (S16: YES), the process proceeds to step S17, where the temperature management unit 53 uses the cooling system 12 to cool the battery 11. As a result, the temperature of the battery 11 is maintained at a temperature equal to or lower than the threshold value Th. Specifically, when the threshold value Th is higher than the high threshold value Th, the process proceeds to step S17. Ｈ When the battery temperature T ｂａｔ The battery 11 is cooled so that the temperature is maintained within the appropriate temperature range. Ｌ When the battery temperature T ｂａｔ The battery 11 is cooled (deterioration prevention cooling) so that the temperature is maintained at or below the low threshold value ThL, that is, so that the temperature is maintained at a lower temperature within an appropriate temperature range.

[0075] 6 is a flowchart relating to the destination determination (S11). Here, a case will be described in which the destination determination unit 51 performs destination determination by referring to the registered destinations 17.

[0076] 6, in step S21, the destination determination unit 51 designates all or part of the registered destinations 17 as specific destinations in advance, in accordance with the attributes of the registered destinations 17. Here, as an example, the destination determination unit 51 designates registered destinations 17 with the labels (attributes) of "home" and "workplace" as specific destinations in advance.

[0077] It should be noted that "home" and "workplace" are typical examples of destinations where the electric vehicle 100 is likely to be stopped for a long period of time after arrival. For example, if the electric vehicle 100 is mainly used for commuting (travel between "home" and "workplace"), the electric vehicle 100 that arrives at the "workplace" is likely to be stopped for approximately 7-8 hours until the driver's workday ends. Furthermore, the electric vehicle 100 that arrives at "home" is likely to be stopped for approximately 12 hours until the driver starts work the next day. Of course, the destination determination unit 51 can designate registered destinations 17 other than "home" and "workplace" as specific destinations.

[0078] In the following description, a registered destination 17 labeled as home may be simply referred to as home, and a registered destination 17 labeled as workplace may be simply referred to as workplace.

[0079] In step S22, the destination determination unit 51 determines whether the current destination is a registered destination 17. When the driver or the like sets a destination in the navigation system 13 by selecting it from the registered destinations 17, the destination determination unit 51 determines that the current destination is a registered destination 17. On the other hand, when the driver or the like sets a new destination by inputting an address or the like or by using a map or the like displayed by the navigation system 13, the destination determination unit 51 determines that the current destination is not a registered destination 17. Note that in this embodiment, when the driver or the like sets a new destination using a map or the like to a location that is substantially the same as a registered destination 17, such as their home or workplace, the destination determination unit 51 determines that the current destination is not a registered destination 17. In other words, when the driver or the like selects a destination from the registered destinations 17 in the navigation system 13, the destination determination unit 51 determines that the current destination is a registered destination 17.

[0080] If it is determined in step S22 that the current destination is a registered destination 17, the process proceeds to step S23. In step S23, the destination determination unit 51 determines whether the registered destination 17 set as the current destination is labeled as "home" or "workplace." If the registered destination 17 set as the current destination is labeled as "home" or "workplace" as specified in advance, the process proceeds to step S24, where the destination determination unit 51 determines that the current destination is a specific destination. On the other hand, if the registered destination 17 set as the current destination is not labeled as "home" or "workplace" as specified in advance, the process proceeds to step S25, where the destination determination unit 51 determines that the current destination is not a specific destination but a general destination.

[0081] That is, when a current destination is selected from the registered destinations 17, the destination determination unit 51 determines the destination according to its label (attribute).

[0082] Furthermore, if it is determined in step S22 that the current destination is a newly set destination and is not a registered destination 17, the process proceeds to step S26. In step S26, the destination determination unit 51 determines whether the current destination is close to "home" or "workplace" that has been previously designated as a specific destination. Specifically, the destination determination unit 51 determines whether the current destination is close to home or the like, for example, based on whether the distance between the current destination and home or the like is equal to or less than a predetermined distance threshold. If it is determined that the current destination is close to home or the like, the process proceeds to step S24, where the destination determination unit 51 determines that the current destination is a specific destination. On the other hand, if it is determined that the current destination is far from home or the like, the process proceeds to step S25, where the destination determination unit 51 determines that the current destination is a general destination.

[0083] 7 is another flowchart related to destination determination (S11). Here, a case will be described in which the destination determination unit 51 determines the destination by referring to the travel history 18 when the driver or the like sets a new destination in the navigation system 13 and the newly set destination is not close to a previously specified specific destination (home or workplace).

[0084] 7, in step S31, the destination determination unit 51 designates in advance the driving history 18 that meets the conditions as a specific driving history. Specifically, the destination determination unit 51 refers to the "stopping time" section of the driving history 18, and designates the driving history 18 in which the "stopping time" is equal to or longer than a predetermined time (typically about 4 to 6 hours) as a specific driving history. In other words, the specific driving history is the driving history 18 in which the destination turned out to be a specific destination.

[0085] Thereafter, in step S32, the destination determination unit 51 determines whether or not the current travel route corresponds to the travel route in the specific travel history.

[0086] Specifically, the destination determination unit 51 acquires the current driving route being guided by the navigation system 13. Then, the destination determination unit 51 determines whether the current driving route matches the driving route in the specific driving history.

[0087] Furthermore, the navigation system 13 normally prepares multiple candidate driving routes to reach the destination. Therefore, when a driving route (hereinafter referred to as an alternative driving route) that is an alternative to the current driving route being guided by the navigation system 13 matches a driving route in the specific driving history, the destination determination unit 51 can determine that the current driving route substantially matches the driving route in the specific driving history.

[0088] In addition, even if the current driving route or the alternative driving route does not match the driving route in the specific driving history, if most of these match, or if the general direction of travel and travel distance, etc. are the same, the destination determination unit 51 can determine that the current driving route substantially matches the driving route in the specific driving history.

[0089] Then, as described above, the destination determination unit 51 determines that the current driving route corresponds to the driving route in the specific driving history when the current driving route matches or substantially matches the driving route in the specific driving history.

[0090] If it is determined in step S32 that the current driving route corresponds to the specific driving history, the process proceeds to step S33. In step S33, the destination determination unit 51 determines whether the current date and time, etc. correspond to the specific driving history.

[0091] For example, the destination determination unit 51 determines whether the current date and time match the weekday / holiday indicated by the date and day of the week in the specific driving history with which the driving route matches (or substantially matches). For example, the destination determination unit 51 determines whether the current date and time are included in the departure time zone of the specific driving history. Furthermore, for example, the destination determination unit 51 determines whether the estimated arrival time of the current driving route is included in the arrival time zone of the specific driving history. When all or most of these conditions match, the destination determination unit 51 determines that the current date and time, etc. correspond to the specific driving history with which the driving route matches. In this embodiment, for simplicity, when all of these conditions are met, i.e., when the current date and time matches the weekday or holiday indicated in the specific driving history, is included in the departure time zone, and the current estimated arrival time is included in the arrival time zone of the specific driving history, the destination determination unit 51 determines that the current date and time, etc. correspond to the specific driving history with which the driving route matches.

[0092] If it is determined in step S33 that the current date, time, etc. correspond to the specific driving history, the process proceeds to step S34, where the destination determination unit 51 determines that the current destination is a specific destination. On the other hand, if it is determined in step S32 that the current driving route does not correspond to the specific driving history, or if it is determined in step S33 that the current date, time, etc. do not correspond to the specific driving history, the process proceeds to step S35, where the destination determination unit 51 determines that the current destination is a general destination.

[0093] 8 is another flowchart related to destination determination (S11). Here, a case will be described in which the destination determination unit 51 determines the destination by referring to the driving history 18 when the driver or the like sets a new destination in the navigation system 13, the newly set destination is not close to a previously specified specific destination (home or workplace), and the driving route or the like does not match the previously specified specific driving history.

[0094] 8, in step S41, the destination determination unit 51 identifies in advance a combination of date, day of the week, and arrival time zone that has a high frequency of "stopping time" being equal to or longer than a predetermined time (typically about 4 to 6 hours) based on the multiple driving histories 18. In other words, the destination determination unit 51 identifies in advance a driving scene (date, day of the week, and arrival time zone) that has a high probability of the current destination eventually becoming a specific destination. In this embodiment, the destination determination unit 51 identifies the driving scene by aggregating various recorded items of the specific driving history.

[0095] In step S42, the destination determination unit 51 determines whether the current date and time match the weekday / holiday indicated by the specified date and day of the week. If it is determined in step S42 that the current date and time match the weekday / holiday indicated by the specified date and day of the week, the process proceeds to step S43, where the destination determination unit 51 further determines whether the estimated arrival time at the current destination is included in the specified arrival time zone. If it is determined in step S43 that the estimated arrival time at the current destination is included in the specified arrival time zone, the process proceeds to step S44, where the destination determination unit 51 determines that the current destination is a specified destination.

[0096] On the other hand, if it is determined in step S42 that the current date and time is different from the weekday / holiday indicated by the specified date and day of the week, or if it is determined in step S43 that the estimated arrival time at the current destination is not included in the specified arrival time zone, the process proceeds to step S45, and the destination determination unit 51 determines that the current destination is a general destination.

[0097] The destination determination unit 51 can perform one or more of the destination determinations shown in Figures 6 to 8. When the results of the destination determinations shown in Figures 6 to 8 conflict, for example, the destination determination unit 51 can finally determine that the current destination is a specific destination when any one of these destination determinations has determined that the current destination is a specific destination.

[0098] 9 is a flowchart relating to the switching of the cooling circuit, and describes the switching control of the cooling circuit performed by the temperature management unit 53 when cooling the battery 11 in step S17.

[0099] As shown in FIG. 9, in step S51, the temperature management unit 53 calculates the battery temperature T ｂａｔ The threshold value Th for Ｌ Check whether the threshold value Th is the low threshold value TH. Ｌ If so, the process proceeds to step S52, and the temperature management unit 53 further adjusts the SOC of the battery 11 to its upper limit value U ｌｉｍ Then, the SOC is compared with the upper limit value U ｌｉｍ If this is the case, the process proceeds to step S53, where the temperature management unit 53 cools the battery 11 using the second cooling circuit 22. As a result, the temperature management unit 53 performs deterioration prevention cooling while actively consuming the power (SOC) of the battery 11.

[0100] On the other hand, in step S51, the threshold value Th is set to the high threshold value Th. Ｈ If the SOC is equal to or exceeds the upper limit value U ｌｉｍ If the temperature is lower than the ambient temperature T ａｔｍ and the first cooling water temperature T ｗ１ Compare.

[0101] In step S54, the outside air temperature T ａｔｍ is the first cooling water temperature T ｗ１ As described above, when the first cooling circuit 21 using the radiator 31 has substantially lost its cooling capacity, the process proceeds to step S53, where the temperature management unit 53 cools the battery 11 using the second cooling circuit 22. That is, the temperature management unit 53 is forced to consume the power (SOC) of the battery 11 while controlling the battery temperature T ｂａｔ is maintained below a threshold value Th.

[0102] In step S54, the outside air temperature T ａｔｍ is the first cooling water temperature T ｗ１When the battery temperature T ｂａｔ is maintained below a threshold value Th.

[0103] In this way, the outside temperature T ａｔｍ is the first cooling water temperature T ｗ１ When the SOC is lower than the upper limit value U ｌｉｍ If the SOC is smaller than the upper limit value U, the first cooling circuit 21 is used. ｌｉｍ If the temperature is equal to or higher than the ambient temperature T ａｔｍ is the first cooling water temperature T ｗ１ As described above, when only the second cooling circuit 22 can be selected for deterioration prevention cooling, the temperature management unit 53 cools the battery 11 using the second cooling circuit 22 .

[0104] In addition, the threshold value Th is set to a high threshold value Th Ｈ In the scene where the outside temperature T ａｔｍ is the first cooling water temperature T ｗ１ When the temperature is lower than the ambient temperature T ａｔｍ is the first cooling water temperature T ｗ１ As described above, when only the second cooling circuit 22 can be selected to cool the battery 11 , the temperature management unit 53 cools the battery 11 using the second cooling circuit 22 .

[0105] FIG. 10 shows the battery temperature T ｂａｔ 10A shows the vehicle speed V. FIG. 10B shows the output P of the battery 11. ｂａｔ The output P ｂａｔis positive when the battery 11 is being charged and negative when the battery 11 is being discharged. Fig. 10(C) shows the SOC of the battery 11. Fig. 10(D) shows the battery temperature T ｂａｔ In FIG. 10, the transition of each of the above parameters in this embodiment is indicated by a solid line, and the transition of each of the above parameters in the comparative example is indicated by a dashed line. In the comparative example, the threshold value Th is always set to the high threshold value Th. Ｈ This is an example in which the setting is 0 and deterioration prevention cooling is not performed.

[0106] 10 shows a scene in which the electric vehicle 100 travels from a "workplace" or the like to a specific destination, "home," and stops. １ is the time when the distance to "home" becomes equal to or shorter than a predetermined distance, or the time when the time to "home" becomes equal to or shorter than a predetermined time. ２ is the arrival time at "home". １ In this embodiment, the threshold value Th is set to the high threshold value Th. Ｈ This is the period set in (normal cooling period). Period A ２ In this embodiment, the threshold value Th is a low threshold value Th Ｌ This is the period during which deterioration prevention cooling is performed. ３ is the period after the vehicle has arrived at the specific destination, ie, the home. Here, the battery 11 is cooled by the second cooling circuit 22.

[0107] As shown in Figure 10(A), for simplicity, it is assumed that the electric vehicle 100 moves from the workplace to the home and stops at a constant speed. At this time, as shown by the dashed lines in Figures 10(B) and 10(C), in the comparative example, the battery 11 consumes a constant amount of power and the SOC decreases. In this way, when power is consumed, the battery 11 generates heat due to internal resistance, etc., but the battery temperature T ｂａｔ is the threshold Th (high threshold Th Ｈ ), the battery 11 is cooled. Therefore, as shown by the dashed line in FIG. 10(D), in the comparative example, １ and A ２ During this period, the battery temperature T ｂａｔ is the high threshold Th ＨWhen the electric vehicle 100 arrives at the home and stops, it takes a long time for the electric vehicle 100 to cool down naturally.

[0108] Therefore, in the comparative example, the battery temperature T ｂａｔ Although the temperature is within the appropriate range, the relatively high temperature continues for a long time. Therefore, even if the battery 11 does not deteriorate in the short term, the deterioration of the battery 11 is likely to be accelerated in the long term. Furthermore, as shown in FIG. 10(C), when the battery 11 is sufficiently charged and the SOC reaches the upper limit value U after arriving home, ｌｉｍ When the temperature is higher than 1000 K, deterioration of the battery 11 is particularly accelerated in the long term.

[0109] In this embodiment, the battery 11 consumes power and the SOC decreases, as in the comparative example. ２ In this case, the threshold value Th is a high threshold value Th Ｈ to low threshold Th Ｌ 10B and 10C, the temperature drops to 0°C, and deterioration prevention cooling is performed before the vehicle arrives at home. Here, deterioration prevention cooling is performed using the second cooling circuit 22. Therefore, in this embodiment, as shown by the solid lines in FIGS. ２ Thereafter, the power consumption of the battery 11 increases compared to the comparative example, and the SOC reaches the upper limit value U ｌｉｍ Then, as shown by the solid line in FIG. 10(D), at time t ２ Hereafter, the threshold value Th is the low threshold value Th Ｌ In this embodiment, the battery temperature T ｂａｔ By the time he arrives home, he has reached a low threshold Ｌ It is cooled to below

[0110] That is, in this embodiment, when the electric vehicle 100 arrives at home, the battery temperature T ｂａｔThe battery 11 is cooled so that the SOC of the battery 11 is relatively low within an appropriate temperature range. As a result, in this embodiment, even if the electric vehicle 100 is parked until the next morning after arriving at home, degradation of the battery 11 is suppressed from a long-term perspective. Furthermore, as shown in FIG. 10(C), when the SOC of the battery 11 reaches the upper limit value U ｌｉｍ Since the battery 11 is reduced to 100%, deterioration of the battery 11 is particularly likely to be suppressed from a long-term perspective.

[0111] As described above, the battery temperature management method according to the above embodiment acquires the temperature of the battery 11 mounted on the electric vehicle 100, and calculates the temperature (T ｂａｔ When the temperature (T ｂａｔ This battery temperature management method determines whether the current destination of the electric vehicle 100 is a specific destination where the vehicle is expected to be stopped continuously for a predetermined time or more, and if the current destination is the specific destination, reduces the threshold value Th.

[0112] In this way, if the threshold value Th is lowered by determining whether the destination (current destination) is a specific destination, the battery temperature T ｂａｔ When there is a high probability that the battery temperature T ｂａｔ is relatively low temperature within the appropriate temperature range (low threshold Th Ｌ The battery 11 is cooled to a temperature T ｂａｔ Compared with the case where the battery 11 is cooled so that the battery temperature T ｂａｔ Compared to a case where the battery 11 is cooled so that the temperature of the battery 11 quickly becomes relatively low, the battery temperature management control that lowers the threshold value Th while driving as described above has the advantage that the operating noise of the cooling system 12 is not noticeable and that the wind 34 generated while driving can be used to cool the battery 11.

[0113] In the battery temperature management method according to the above embodiment, a specific destination is designated in advance from among the registered destinations 17 registered in the navigation system 13, and the navigation system 13 determines whether the current destination is a specific destination based on whether the registered destination designated as a specific destination is set as the current destination.

[0114] In this way, by specifying a specific destination from among the registered destinations 17 in the navigation system 13, it is possible to easily and reliably determine whether the current destination is a specific destination. This makes it particularly easy to suppress battery deterioration from a long-term perspective.

[0115] In the battery temperature management method according to the above embodiment, a registered destination that is registered as a home or workplace is designated as a specific destination.

[0116] Since home and workplace are typical examples of destinations where the electric vehicle 100 is likely to be stopped for a long time after arrival, if home or workplace is designated as a specific destination, battery deterioration is particularly likely to be suppressed from a long-term perspective.

[0117] In the battery temperature management method according to the above embodiment, when the home or workplace is registered in the navigation system 13 and a current destination different from the home or workplace is set in the navigation system 13, the current destination set in the navigation system 13 is compared with the home or workplace, and if the distance between the current destination set in the navigation system 13 and the home or workplace is less than or equal to a predetermined distance threshold, the current destination is determined to be a specific destination.

[0118] In this way, when a destination that is newly set without being selected from the registered destinations 17 is close to a registered destination 17 designated as a specific destination and there is a high probability that the newly set destination is essentially a previously designated specific destination, it is preferable to determine (estimate) this as a specific destination. In this way, even if a destination is newly set without being selected from the registered destinations 17, appropriate deterioration prevention cooling can be performed.

[0119] In the battery temperature management method according to the above embodiment, a driving history 18 including information on at least the driving route and departure time zone is saved in advance, the current driving route and the current date and time are compared with a specific driving history, which is the driving history 18 when the destination is a specific destination, and when the current driving route and the current date and time correspond to the specific driving history, it is determined that the current destination is a specific destination corresponding to the specific driving history.

[0120] In this way, by determining whether the current destination is a specific destination based on the driving history 18, it is possible to appropriately perform deterioration prevention cooling in cases such as when a new destination is set and the destination is not close to a previously specified specific destination (home or workplace).

[0121] In the battery temperature management method according to the above embodiment, the driving history 18 includes information on the date and day of the week in addition to the driving route and departure time, and when the current driving route corresponds to the driving route in the specific driving history and the current date and time corresponds to the departure time, date, and day of the week in the specific driving history, the current destination is determined to be a specific destination.

[0122] In this way, by determining whether the current destination is a specific destination based on the driving history 18, it is possible to appropriately perform deterioration prevention cooling in cases such as when a new destination is set and the destination is not close to a previously specified specific destination (home or workplace).

[0123] In the battery temperature management method according to the above embodiment, a travel history 18 that associates at least a destination, a date, a day of the week, an arrival time zone during which the vehicle arrives at the destination, and a stopping time at the destination is stored in advance, and a combination of a date, a day of the week, and an arrival time zone during which the stopping time is frequently equal to or longer than a predetermined time is identified in advance based on the plurality of travel histories 18. Then, when the current date and time correspond to the identified date and day of the week, and the estimated arrival time at the current destination is included in the identified arrival time zone, the current destination is determined to be a specific destination.

[0124] In this way, by determining whether the current destination is a specific destination based on the driving history 18, deterioration prevention cooling can be performed appropriately even in cases where a new destination is set and is not close to a previously specified specific destination and the driving route, etc. does not match the specific driving history.

[0125] In the battery temperature management method according to the above embodiment, if the current destination is a specific destination, the threshold value Th is lowered when the remaining distance to the current destination becomes equal to or less than a predetermined distance, or when the remaining time to the current destination becomes equal to or less than a predetermined time.

[0126] When the current destination is a specific destination, the threshold value Th is always set to the low threshold value Th. Ｌ If the battery temperature is set to T and the deterioration prevention cooling is performed, the disadvantages of a worsening of the power consumption and a reduction in the cruising range may become significant depending on the distance or time to the current destination. The deterioration prevention cooling is also performed to prevent the battery from remaining in a relatively high temperature state for a long time after arriving at the destination. In other words, the deterioration prevention cooling is performed when the battery temperature T ｂａｔ the low threshold Th Ｌ Therefore, even if the current destination is a specific destination, it is not necessary to perform deterioration prevention cooling all the time while traveling. Therefore, as described above, by lowering the threshold value Th and performing deterioration prevention cooling immediately before arriving at the destination, it is possible to perform deterioration prevention cooling appropriately while minimizing the disadvantages of a deterioration in power efficiency and a reduction in cruising range.

[0127] In the battery temperature management method according to the above embodiment, the battery 11 is cooled by a water-cooling method in which cooling water is circulated through the battery 11 or by an air-cooling method in which air is blown to the battery 11 .

[0128] In this way, the deterioration prevention cooling can be performed by using a water cooling method, an air cooling method, or a combination of both.

[0129] In the above embodiment, the electric vehicle 100 has a first cooling circuit 21 that circulates coolant (first coolant) between the battery 11 and the radiator 31 that is cooled by outside air, and a second cooling circuit 22 that circulates coolant (second coolant) between the battery 11 and a chiller 42 that is cooled by the refrigerant of an air conditioning system 41. In the battery temperature management method according to the above embodiment, the state of charge (SOC) of the battery 11 is set to a predetermined upper limit value U ｌｉｍ When the threshold value Th is lowered, the state of charge (SOC) becomes equal to the upper limit value U ｌｉｍ When the threshold value Th is smaller than the upper limit value U, the battery 11 is cooled by the first cooling circuit 21, and when the threshold value Th is lowered, the state of charge (SOC) ｌｉｍ If this is the case, the battery 11 is cooled by the second cooling circuit 22 .

[0130] The deterioration of the battery 11 in the long term is caused by the battery temperature T ｂａｔ Therefore, as described above, when the SOC is higher than the upper limit value U ｌｉｍ In the above cases, actively consuming the power of the battery 11 using the second cooling circuit 22 is likely to suppress battery deterioration, particularly from a long-term perspective.

[0131] The battery temperature management device according to the above embodiment is configured to monitor the temperature (T ｂａｔ ) and the temperature (T ｂａｔ When the temperature (T ｂａｔ The battery temperature management device (controller 14) includes a destination determination unit 51 that determines whether the current destination of the electric vehicle 100 is a specific destination where the vehicle is expected to be stopped continuously for a predetermined time or more, and a threshold setting unit 52 that lowers the threshold value Th when the current destination is the specific destination.

[0132] In this way, the controller 14 determines whether the destination (current destination) is a specific destination and then lowers the threshold value Th. ｂａｔ When the battery temperature T ｂａｔ is relatively low temperature within the appropriate temperature range (low threshold Th Ｌ As a result, the controller 14 can suppress deterioration of the battery 11 from a long-term perspective. ｂａｔ Compared with the case where the battery 11 is cooled so that the battery temperature T ｂａｔ Compared to a case where the battery 11 is cooled so that the temperature of the battery 11 quickly becomes relatively low, the battery temperature management control that lowers the threshold value Th while driving as described above has the advantage that the operating noise of the cooling system 12 is not noticeable and that the wind 34 generated while driving can be used to cool the battery 11.

[0133] Although the embodiments of the present invention have been described above, the configurations described in the above embodiments merely show some of the application examples of the present invention and are not intended to limit the technical scope of the present invention.

Claims

1. A battery temperature management method that acquires the temperature of a battery mounted on an electric vehicle, and when the temperature of the battery is equal to or higher than a predetermined threshold, cools the battery to maintain the temperature of the battery at or below the threshold, and determines whether the current destination of the electric vehicle is a specific destination where the vehicle is expected to be stopped continuously for a predetermined period of time or more, and when the current destination is the specific destination, lowers the threshold.

2. A battery temperature management method as claimed in claim 1, comprising: designating the specific destination in advance from among registered destinations registered in a navigation system; and determining whether the current destination is the specific destination based on whether the registered destination designated as the specific destination is set as the current destination in the navigation system.

3. A battery temperature management method according to claim 2, wherein the registered destination registered as a home or workplace is designated as the specific destination.

4. A battery temperature management method as described in claim 1, wherein, when a home or workplace is registered in a navigation system and a current destination different from the home or workplace is set in the navigation system, the current destination set in the navigation system is compared with the home or workplace, and when the distance between the current destination set in the navigation system and the home or workplace is equal to or less than a predetermined distance threshold, the current destination is determined to be the specific destination.

5. A battery temperature management method as claimed in claim 1, comprising: pre-storing a driving history including at least information relating to the driving route and departure time zone; comparing the current driving route and current date and time with a specific driving history, which is the driving history when the destination is the specific destination; and determining that the current destination is the specific destination corresponding to the specific driving history when the current driving route and the current date and time correspond to the specific driving history.

6. A battery temperature management method as set forth in claim 5, wherein the driving history includes information relating to the date and day of the week in addition to the driving route and departure time zone, and when the current driving route corresponds to the driving route in the specific driving history and the current date and time corresponds to the departure time zone, date, and day of the week in the specific driving history, it is determined that the current destination is the specific destination.

7. A battery temperature management method as claimed in claim 1, comprising: pre-storing a driving history that associates at least a destination, a date, a day of the week, an arrival time zone during which the vehicle arrives at the destination, and a stopping time at the destination; identifying, based on a plurality of driving histories, a combination of a date, a day of the week, and an arrival time zone for which the stopping time is frequently equal to or longer than the predetermined time; and determining that the current destination is the specified destination when the current date and time correspond to the identified date and day of the week and the estimated time of arrival at the current destination is included in the identified arrival time zone.

8. A battery temperature management method as claimed in claim 1, wherein, when the current destination is the specific destination, the threshold is lowered when the remaining distance to the current destination is equal to or less than a predetermined distance, or when the remaining time to the current destination is equal to or less than a predetermined time.

9. A battery temperature management method according to claim 1, wherein the battery is cooled by a water-cooling method in which cooling water is circulated through the battery, or by an air-cooling method in which air is blown through the battery.

10. A battery temperature management method as recited in claim 1, wherein the electric vehicle has a first cooling circuit that circulates coolant between the battery and a radiator cooled by outside air, and a second cooling circuit that circulates coolant between the battery and a chiller cooled by refrigerant from an air conditioning system, the battery temperature management method comprising: comparing the charging rate of the battery with a predetermined upper limit value; lowering the threshold value and, when the charging rate is less than the upper limit value, cooling the battery by the first cooling circuit; and lowering the threshold value and, when the charging rate is equal to or greater than the upper limit value, cooling the battery by the second cooling circuit.

11. A battery temperature management device that acquires the temperature of a battery mounted on an electric vehicle, and, when the temperature of the battery is equal to or higher than a predetermined threshold, cools the battery to maintain the temperature of the battery at or below the threshold, the battery temperature management device comprising: a destination determination unit that determines whether the current destination of the electric vehicle is a specific destination where the vehicle is expected to be stopped continuously for a predetermined period of time or more; and a threshold setting unit that lowers the threshold when the current destination is the specific destination.

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