Battery temperature management method and battery temperature management device

Abstract

The temperature of the battery in the electric vehicle is acquired. If the battery temperature is above a preset threshold, the battery temperature is maintained below the threshold by cooling. At this point, it is determined whether the electric vehicle's current destination is a specific destination for which a predetermined period of continuous parking is expected. If the current destination is a specific destination, the threshold is lowered.

Description

Technical Field

[0001] This invention relates to a battery temperature management method and a battery temperature management device for managing the temperature of batteries used in electric vehicles. Background Technology

[0002] JP2019-170028A discloses a battery cooling control device that predicts the remaining battery power when arriving at the destination, calculates the available cooling energy that can be used to cool the battery based on the predicted remaining power, and uses the available cooling energy to cool the battery during the journey to the destination. Summary of the Invention

[0003] To prevent rapid degradation and damage, batteries should be used within a suitable temperature range. Therefore, even with repeated prolonged use at high temperatures, as long as the battery remains within the appropriate temperature range, it will not experience significant degradation in the short term. However, repeated prolonged use at high temperatures, even within the appropriate temperature range, will accelerate battery degradation in the long run.

[0004] Therefore, to suppress long-term degradation, it is preferable to slightly overcool the battery to maintain a low temperature within an appropriate temperature range. On the other hand, if the battery temperature cannot be maintained for an extended period after slightly overcooling, such overcooling only results in deterioration of power consumption and a reduction in the electric vehicle's driving range. Therefore, such slightly overcooling should not be performed continuously, and it is preferable to perform it only when scenarios where the battery temperature remains high for an extended period are identified.

[0005] The purpose of this invention is to provide a battery temperature management method and a battery temperature management device, which cools the battery by identifying scenarios where the battery temperature remains high for an extended period of time, thereby suppressing battery degradation from a long-term perspective.

[0006] One aspect of this invention is a battery temperature management method that acquires the temperature of the battery in an electric vehicle. When the battery temperature exceeds a preset threshold, the battery is cooled to maintain its temperature below the threshold. In this battery temperature management method, it is determined whether the electric vehicle's current destination is a specific destination for which continuous parking is expected for a specified time. If the current destination is a specific destination, the threshold is lowered. Attached Figure Description

[0007] Figure 1 It is a block diagram representing the general structure of an electric vehicle.

[0008] Figure 2 This is an explanatory diagram showing the structure of the cooling system.

[0009] Figure 3 This is an explanatory diagram showing other structures of the cooling system.

[0010] Figure 4 It is a block diagram representing the structure of the controller.

[0011] Figure 5 This is a flowchart of battery temperature management and control.

[0012] Figure 6 This is a flowchart for destination determination.

[0013] Figure 7 This is another flowchart for destination determination.

[0014] Figure 8 This is another flowchart for destination determination.

[0015] Figure 9 This is a flowchart of the cooling circuit switching process.

[0016] Figure 10 It is a graph that schematically represents the change in battery temperature, etc. Detailed Implementation

[0017] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0018] Figure 1 This is a block diagram illustrating the general structure of an electric vehicle 100. The electric vehicle 100 is a vehicle that generates all or part of its driving force through electrical energy. Specifically, the electric vehicle 100 is, for example, an electric car or a hybrid vehicle.

[0019] like Figure 1 As shown, the electric vehicle 100 includes an electric powertrain 10, a battery 11, a cooling system 12, a navigation system 13, and a controller 14.

[0020] The electric powertrain 10 is the power source for the electric vehicle 100. The electric powertrain 10 consists of, for example, an electric motor, an inverter, and a reducer. Illustrations of the electric motor, etc., are omitted here.

[0021] The battery 11 supplies the required electrical energy to the electric powertrain 10 and other parts of the electric vehicle 100. Furthermore, the battery 11 is rechargeable. Specifically, the battery 11 is, for example, composed of a lithium-ion battery.

[0022] Battery 11 deteriorates due to repeated discharge and charge cycles (deterioration over time). Additionally, the temperature of battery 11 (hereinafter referred to as battery temperature T)... batUsing battery 11 under high or low temperatures will also degrade its performance. Therefore, in electric vehicle 100, the battery temperature T... bat The battery is managed to maintain a temperature within a pre-set appropriate temperature range, at least during use. That is, the battery 11 is cooled or heated as needed to ensure operation within a suitable temperature range. The appropriate temperature range for the battery 11 is typically, for example, from about 0°C to about 45°C. Furthermore, the optimal battery temperature T... bat It is usually around 20°C to around 30°C.

[0023] If the battery temperature T bat If managed within this appropriate temperature range, battery 11 is in principle unlikely to degrade. That is, if used within the appropriate temperature range, it will not promote the degradation of battery 11, at least in the short term. However, even if the battery temperature T... bat Maintaining it within a suitable temperature range, if at battery temperature T bat Prolonged and repeated use at temperatures higher than the optimal temperature (e.g., approximately 20°C to 30°C) and close to the upper limit (e.g., approximately 45°C) will lead to long-term degradation of the battery. For convenience, the battery temperature T will be used as follows: bat A temperature that is higher than a certain range is called a high temperature.

[0024] The cooling system 12 is a system for cooling the heat-generating components in the electric vehicle 100. In this embodiment, the cooling system 12 cools the electric powertrain 10 and the battery 11. The specific structure of the cooling system 12 will be described later.

[0025] The navigation system 13 is a system that guides the driver to a destination by pre-setting the destination and provides the estimated arrival time (time required). The navigation system 13 uses a GPS (Global Positioning System) receiver (not shown) or similar device to obtain the current location of the electric vehicle 100. Furthermore, the navigation system 13 uses location information, map data 16, registered destination 17, and driving records 18 to provide information related to the driving route and estimated arrival time to the driver or other users (hereinafter referred to as "driver, etc.").

[0026] Map data 16 is a collection of information related to road networks, terrain, and attributes of facilities, etc. Attributes of facilities, etc., include information such as the name of the facility, the business activities of the facility (e.g., restaurants, accommodations, entertainment facilities, or museums).

[0027] The registered destination 17 refers to the location of a place (location) that is set and registered in the navigation system 13, or a candidate location (hereinafter referred to as the registered destination). The registered destination 17 is preset by the driver and other users. In addition, multiple registered destinations 17 can be registered in the navigation system 13. Furthermore, in addition to information related to location, i.e., coordinates on a map, the registered destination 17 sometimes includes its attributes (or labels indicating attributes). Specifically, these are "home", "workplace (employer)", etc. In this embodiment, at least "home" and "workplace" are set as registered destinations 17 in the navigation system 13.

[0028] The driving record 18 stores data such as the actual routes traveled by the electric vehicle 100 in the past. For example, the driving record 18 is data that links the destination, driving route, departure time or time period to the destination (departure time or departure time period), travel time or time period (travel time or travel time period), month and day, weekday, arrival time or time period at the destination (arrival time or arrival time period), and parking time at the destination. In this embodiment, the driving record 18 includes information on the destination, driving route, departure time period, month and day, weekday, arrival time period, and parking time.

[0029] The "Departure Time Period" in Driving Record 18 indicates the time period to which the electric vehicle 100 begins its journey towards its destination. The "Month / Day" and "Weekday" in Driving Record 18 are used to identify weekdays and rest days (holidays). The "Arrival Time Period" in Driving Record 18 indicates the time period to which the vehicle arrives at its destination. The arrival time period is divided similarly to the departure time period. The "Stopping Time" in Driving Record 18 is recorded, for example, by measuring the time from when the power switch (ignition switch) is turned off at the destination until the next time the power switch is turned on.

[0030] In addition, time periods such as departure and arrival times are divided into categories such as early morning (0:00-3:00), dawn (3:00-6:00), morning (6:00-9:00), morning (9:00-12:00), afternoon (12:00-15:00), evening (15:00-18:00), night (18:00-21:00), and late night (21:00-24:00).

[0031] The controller 14 is a control device that uniformly controls all parts of the electric vehicle 100. The controller 14 may be composed of one or more computers.

[0032] In this embodiment, the controller 14 functions as a battery temperature management device, which manages the temperature of the battery 11 by appropriately cooling the battery 11 using the cooling system 12, so that the battery temperature T bat The temperature must be maintained at least within a suitable range. Furthermore, the program used to enable the controller 14 to function as a battery temperature management device is a battery temperature management program. Hereinafter, the control by which the controller 14 manages the temperature of the battery 11 will be referred to as battery temperature management control.

[0033] Furthermore, the controller 14 is capable of appropriately acquiring (calculating) the battery temperature T using sensors (not shown) or the like. bat The charging rate (SOC: State of Charge) of battery 11, and the ambient air temperature T. atm The controller 14 also monitors the temperatures of various cooling water sources and other parameters required for battery temperature management and control. Furthermore, the controller 14 uses the current date and time (current month, day, week, time, etc.) in the battery temperature management and control. In this embodiment, the current date and time are updated and managed by the controller 14 itself, and are known information to the controller 14.

[0034] The controller 14, acting as a battery temperature management device, monitors the battery temperature T. bat Set a threshold Th at battery temperature T bat When the temperature exceeds the threshold Th, the cooling system 12 is used to cool the battery 11. Therefore, the controller 14 sets the battery temperature T... bat It remains below the threshold Th.

[0035] The threshold Th is, in principle, set to the upper limit of the appropriate temperature range of battery 11 or a temperature below it. Therefore, controller 14 cools battery 11, thereby substantially reducing battery temperature T. bat Maintain within a suitable temperature range.

[0036] However, in this embodiment, the threshold Th is variable. Specifically, the controller 14 lowers the threshold Th based on the current destination of the electric vehicle 100. When the threshold Th is lowered, the controller 14 cools the battery 11 within an appropriate temperature range until the battery temperature T... bat It becomes a lower temperature.

[0037] The following will address battery temperature T. bat The set, standard threshold Th is called the high threshold Th. H (First threshold), the threshold Th that is lowered based on the current destination is called the low threshold Th. L (Second threshold). Therefore, if the upper limit of the appropriate temperature range for battery 11 is set to T...UL Set the lower limit value to T LL Then T UL >Th H >Th L >T LL .

[0038] Furthermore, as described above, in order to suppress the degradation of battery 11 under long-term conditions, preventative cooling of battery 11 is performed to lower the threshold Th, thereby reducing the battery temperature T. bat Maintain at a low threshold Th L Therefore, the following will cause the threshold Th to change from the high threshold Th. H Reduce to a low threshold Th L The cooling of battery 11 is called degradation prevention cooling.

[0039] Furthermore, the controller 14 can set the threshold Th substantially individually based on the specific nature (attributes) of the current destination. That is, the controller 14 can set different low threshold values ​​Th for each destination. L However, for simplicity in this embodiment, it is assumed to be based on battery temperature T. bat The threshold Th is set to a high threshold based on the current destination. H and low threshold Th L Any value in the range. That is, in this embodiment, the controller 14 selects a value from the high threshold Th based on the nature of the current destination, etc. H or low threshold Th L Choose the threshold Th from these two values.

[0040] Figure 2 This is an explanatory diagram showing the structure of the cooling system 12. (For example...) Figure 2 As shown, the cooling system 12 serves as a cooling circuit for cooling the battery 11, and for example, it includes two cooling circuits: a first cooling circuit 21 and a second cooling circuit 22.

[0041] The first cooling circuit 21 is a battery cooling circuit that cools the battery 11 by circulating cooling water and other coolants (hereinafter simply referred to as cooling water) between the battery 11 and the radiator 31. It should be noted that in this embodiment, the first cooling circuit 21 is also an electric powertrain cooling circuit that cools the electric powertrain 10 by circulating cooling water between the electric powertrain 10 and the radiator 31. The controller 14, by controlling valves (not shown) or the like, can use the first cooling circuit 21 to circulate cooling water only in the battery 11 or only in the electric powertrain 10. That is, the first cooling circuit 21 can cool the battery 11, the electric powertrain 10, or both as needed.

[0042] Specifically, the first cooling circuit 21 includes a radiator 31, a first cooling water circuit 32, and a pump 33.

[0043] The radiator 31 uses the ambient airflow 34 to cool the cooling water (hereinafter referred to as the first cooling water) flowing in the first cooling water passage 32. The first cooling water passage 32 is configured to circulate the first cooling water between the radiator 31, the electric powertrain 10, and the battery 11. The pump 33 pressurizes the first cooling water in the first cooling water passage 32. The pump 33 is driven by the electrical energy of the battery 11, but it consumes very little electrical energy. Therefore, when the battery 11 is cooled using the first cooling circuit 21, the state of charge (SOC) of the battery 11 hardly decreases through this cooling.

[0044] The second cooling circuit 22 is a battery cooling circuit that uses an air conditioning (HVAC) system 41 to cool the battery 11. Specifically, the second cooling circuit 22 includes an air conditioning system 41, a cooler 42, a second cooling water circuit 43, and a pump 44.

[0045] The air conditioning system 41 is a system that regulates the temperature of the passenger compartment by repeatedly compressing and expanding the refrigerant. The air conditioning system 41 consists of a refrigerant circulation path 45 that circulates the refrigerant, a compressor 46 that compresses the refrigerant, and an expansion valve (not shown) that expands the refrigerant.

[0046] Cooler 42 is a heat exchanger added to the refrigerant circulation path 45 of the air conditioning system 41 for cooling the battery 11. Cooler 42 cools the cooling water and other coolant (hereinafter referred to as second cooling water) 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 cooling water between the battery 11 and cooler 42. Pump 44 pressurizes the second cooling water in the second cooling water path 43.

[0047] Therefore, the second cooling circuit 22 is a battery cooling circuit that cools the battery 11 by circulating cooling water between the cooler 42, which is cooled by the refrigerant of the air conditioning system 41, and the battery 11.

[0048] Furthermore, pump 44 is driven by the power of battery 11, but its power consumption is very low. Additionally, compressor 46 is also driven by the power of battery 11, but its power consumption is significantly higher than that of pumps 33 and 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, when the state of charge (SOC) of battery 11 should be actively consumed, the second cooling circuit 22 is used to cool battery 11. On the other hand, when the state of charge (SOC) of battery 11 does not need to be consumed, the first cooling circuit 21 is used to cool battery 11 in principle.

[0049] Furthermore, the first cooling circuit 21 and the second cooling circuit 22 can be used in combination. Therefore, in scenarios where it is necessary to actively consume the electrical energy (SOC) of the battery 11 and quickly cool the battery 11, the battery 11 will be cooled using both the first cooling circuit 21 and the second cooling circuit 22.

[0050] Furthermore, 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 as needed using valves and water passages (not shown). For example, when the air conditioning system 41 is used to cool the electric powertrain 10, 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, the first cooling water passage 32 and the second cooling water passage 43 are assumed to be disconnected (connection released).

[0051] In this embodiment, as described above, the cooling system 12 includes a first cooling circuit 21 that uses a radiator 31 to cool the battery 11 and a second cooling circuit 22 that uses an air conditioning system 41 to cool the battery 11, but is not limited thereto.

[0052] Figure 3 This is an explanatory diagram showing other structures of the cooling system 12. (e.g.) Figure 3 As shown, the cooling system 12 can also consist of a first cooling circuit 21 that uses a radiator 31 to cool the battery 11 and a third cooling circuit 23 that uses a blower fan 47 to cool the battery 11. The blower fan 47 cools the battery 11 by supplying running air 34 (outdoor air) to the battery 11. In this case, the blower fan 47 and the flow path of the air supplied by the blower fan 47 constitute the third cooling circuit 23.

[0053] It should be noted that the fan 47 is powered by the battery 11, but it consumes very little power. Therefore, when the battery 11 is cooled by the third cooling circuit 23, the state of charge (SOC) of the battery 11 hardly decreases. Furthermore, the first cooling circuit 21 and the third cooling circuit 23 can be used concurrently.

[0054] Furthermore, the cooling system 12 can also be configured to omit the blower fan 47 and directly supply the driving air 34 (outdoor air) into the battery 11. In this case, the flow path of the driving air 34 constitutes the third cooling circuit 23. Alternatively, the cooling system 12 may include all of the aforementioned first cooling circuit 21, second cooling circuit 22, and third cooling circuit 23. The first cooling circuit 21 and second cooling circuit 22 are water-cooled cooling circuits that circulate cooling water in the battery 11, and the third cooling circuit 23 is an air-cooled cooling circuit that supplies air to the battery 11. Therefore, the degradation prevention cooling of this embodiment can be implemented using water cooling, air cooling, or both.

[0055] Unless otherwise specified, the cooling system 12 is as follows: Figure 2 As shown, it is configured to consist of a first cooling circuit 21 and a second cooling circuit 22.

[0056] Figure 4 This is a block diagram showing the structure of controller 14. Here, the functional structure of controller 14, particularly the parts constituting the battery temperature management device, will be explained. For example... Figure 4 As shown, the controller 14 includes a destination determination unit 51, a threshold setting unit 52, and a temperature management unit 53.

[0057] The destination determination unit 51 determines whether the current destination of the electric vehicle 100 is a specific destination.

[0058] The destination determination unit 51 uses the navigation system 13 to obtain the current destination. Specifically, when the driver or others set a destination in the navigation system 13, the destination determination unit 51 obtains information related to the destination set in the navigation system 13 and uses it as the current destination.

[0059] On the other hand, when the driver or others have not set a destination in the navigation system 13, the destination determination unit 51 can estimate the current destination. Specifically, when no destination is set in the navigation system 13, the destination determination unit 51 obtains the current driving route and driving record 18 of the electric vehicle 100 from the navigation system 13. Then, the destination determination unit 51 compares the current driving route and the current date and time with the driving record 18. As a result of this comparison, if there is a driving record 18 corresponding to the current driving route and the current date and time, the destination of that driving record 18 is estimated as the current destination. Furthermore, the current driving route is information that determines the current position of the electric vehicle 100 or the road on which the electric vehicle 100 is currently traveling.

[0060] In this embodiment, for simplicity, it is assumed that the driver sets a destination in the navigation system 13. The driver can set a destination by selecting one or more pre-set registered destinations 17 in the navigation system 13, for example. In addition, when a location not set as a registered destination 17 is the destination, the driver can set a destination by touching a map or searching for an address, facility name, etc. on the display screen (not shown) of the navigation system 13.

[0061] A specific destination is a destination where the vehicle is expected to remain parked (or parked) for a specified period of time or more upon arrival. In other words, a specific destination is one where the battery 11 is likely to be left at a high temperature (a relatively high temperature within a suitable temperature range) upon arrival, and therefore, deterioration prevention cooling should be implemented. Therefore, the specified time mentioned here refers to the time during which the battery 11 continues to be at a high temperature, contributing to the degree of degradation of the battery 11. This specified time is determined in advance based on experiments or simulations, taking into account the specific characteristics of the battery 11. Specifically, the specified time is approximately 4 to 6 hours.

[0062] The destination determination unit 51 determines whether the current destination is a specific destination based on the attributes (tags) of the registered destination 17 or the driving record 18 (hereinafter referred to as destination determination). The specific method of destination determination will be described in detail below.

[0063] The threshold setting unit 52 sets or changes the threshold for battery temperature T based on the destination determination result. bat The threshold Th. Specifically, when the destination determination process determines 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 will set the threshold based on the battery temperature T. bat The threshold Th is set to a high threshold Th. H On the other hand, when the current destination is determined to be a specific destination during destination determination, the threshold setting unit 52 will set the threshold based on the battery temperature T. batThe threshold Th is changed to a lower threshold Th L The default value for threshold Th is the high threshold Th. H .

[0064] Furthermore, the threshold setting unit 52 determines whether to set or change the threshold Th based on the remaining distance to the current destination, the remaining time to the current destination, or both, according to the result of the destination determination. That is, the threshold setting unit 52 determines when to lower the threshold Th based on the result of the destination determination, according to the remaining distance to the current destination or the remaining time to the current destination.

[0065] Specifically, the threshold setting unit 52 determines, for example, whether the distance (remaining distance) from the current position to the current destination along the current driving route is less than a predetermined distance. Then, if the remaining distance is longer than the predetermined distance, the threshold setting unit 52, in principle, sets the threshold based on the battery temperature T regardless of the destination determination result. bat The threshold Th is set to the high threshold Th, which is the default value. H Subsequently, when the remaining distance is below the specified distance, the threshold setting unit 52 sets or changes the threshold for battery temperature T based on the destination determination result. bat The threshold Th.

[0066] Additionally, the threshold setting unit 52 determines, for example, whether the remaining time (time until reaching the current destination from the current location according to the current driving route) is less than a predetermined time. Then, if the remaining time is longer than the predetermined time, the threshold setting unit 52, in principle, sets the threshold based on the battery temperature T regardless of the destination determination result. bat The threshold Th is set to the high threshold Th, which is the default value. H Subsequently, when the remaining time falls below a predetermined time, the threshold setting unit 52 sets or changes the threshold for battery temperature T based on the destination determination result. bat The threshold Th.

[0067] In this embodiment, when at least one of the conditions related to remaining distance or remaining time is met, the threshold setting unit 52 sets or changes the threshold for battery temperature T based on the destination determination result. bat The threshold Th.

[0068] It should be noted that the aforementioned "prescribed distance" is predetermined based on the thermal capacity of battery 11 and the cooling capacity of cooling system 12 for battery 11, so that when electric vehicle 100 reaches its current destination, the battery temperature T is maintained by preventing deterioration of cooling. bat Reaching the low threshold Th LSimilarly, the aforementioned "predetermined time" is predetermined based on the thermal capacity of battery 11 and the cooling capacity of cooling system 12 for battery 11, so that when electric vehicle 100 arrives at its current destination, the battery temperature T is maintained by preventing deterioration through cooling. bat Reaching the low threshold Th L In this embodiment, the "prescribed distance" and "prescribed time" are preset based on experiments or simulations.

[0069] It should be noted that the cooling capacity of the cooling system 12 for the battery 11 varies depending on whether the first cooling circuit 21 is used for degradation prevention cooling, the second cooling circuit 22 is used for degradation prevention cooling, or both the first cooling circuit 21 and the second cooling circuit 22 are used for degradation prevention cooling. Therefore, the aforementioned "specified distance" and "specified time" will vary depending on the specific cooling circuit structure used in degradation prevention cooling.

[0070] The temperature management unit 53 manages the temperature of the battery 11 to ensure that the battery temperature T bat The temperature is maintained below the threshold Th. In this embodiment, the temperature management unit 53 maintains the battery temperature T. bat When the threshold Th is reached or exceeds the threshold, the battery 11 is cooled by the cooling system 12. Therefore, the threshold Th is set to a high threshold Th. H At that time, the temperature management unit 53 appropriately cools the battery 11 so that the battery temperature T bat Maintain the temperature within an appropriate temperature range. Furthermore, when the threshold Th changes to a lower threshold Th... L At that time, the temperature management unit 53 performs deterioration prevention cooling to keep the battery temperature T bat Maintain a low threshold Th L The following temperatures.

[0071] Temperature Management Department 53, in principle, based on the outside air temperature T atm The temperature of the first cooling water (hereinafter referred to as the first cooling water temperature T) w1 The size relationship is used to switch the cooling circuit used in the cooling of battery 11.

[0072] Specifically, at an outside air temperature T atm Compared to the first cooling water temperature T w1 When the temperature is low and the first cooling circuit 21 using the heat sink 31 has cooling capacity, the temperature management unit 53 will, in principle, cool the battery 11 through the first cooling circuit 21.

[0073] On the other hand, when the outside air temperature T atm The first cooling water temperature T w1At temperatures above these levels, the first cooling water cannot be cooled by the airflow 34 (outside air). That is, the cooling capacity of the first cooling circuit 21 is essentially lost. Therefore, at outside air temperatures T... atm The first cooling water temperature T w1 In the above situations, when it is necessary to cool the battery 11, the temperature management unit 53 cools the battery 11 through the second cooling circuit 22.

[0074] Furthermore, when the threshold Th is reduced to a lower threshold Th L When performing deterioration prevention cooling, the temperature management unit 53 also switches the cooling circuit used in cooling the battery 11 according to the SOC of the battery 11.

[0075] Specifically, the temperature management unit 53 sets an upper limit U for the state of charge (SOC) of the battery 11. lim Then, the SOC of battery 11 is at the upper limit value U. lim In the following cases, the temperature management unit 53 cools the battery 11 using the first cooling circuit 21 of the heat sink 31. Thus, the temperature management unit 53 performs deterioration prevention cooling with almost no energy consumption from the battery 11.

[0076] On the other hand, the SOC of battery 11 is higher than the upper limit U. lim In high-temperature conditions, the temperature management unit 53 cools the battery 11 using the second cooling circuit 22 of the air conditioning system 41. Thus, the temperature management unit 53 actively utilizes the electrical energy of the battery 11 for deterioration prevention cooling.

[0077] When battery 11 is maintained at a high temperature (a relatively high temperature within an appropriate temperature range), high SOC can particularly promote the degradation of battery 11. Therefore, in scenarios where degradation prevention cooling should be performed, when the SOC of battery 11 is high, as described above, by actively utilizing the electrical energy of battery 11 through the second cooling circuit 22, it is particularly easy to suppress the degradation of battery 11 from a long-term perspective.

[0078] In addition, regarding the upper limit U of SOC lim The upper limit value U is preset according to the specific characteristics of battery 11. In this embodiment, the upper limit value U is... lim Pre-set based on experiments or simulations.

[0079] Figure 5 This is a flowchart of battery temperature management control. For example... Figure 5 As shown, 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, determines whether the current destination is a specific destination.

[0080] If, in step S11, 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 threshold based on the battery temperature T. bat The threshold Th is set to a high threshold Th. H .

[0081] 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 greater than the predetermined distance, the process proceeds to step S14, where the threshold setting unit 52 determines whether the current destination will be reached within a predetermined time. Then, if it is determined in step S14 that reaching the current destination will require more time than the predetermined time, the process proceeds to step S12, where the threshold setting unit 52 sets the threshold based on the battery temperature T. bat The threshold Th is set to a high threshold Th. H That is, even if the current destination is a specific destination, if the remaining distance to the current destination is longer than the specified distance and the remaining time to the current destination is longer than the specified time, the threshold setting unit 52 will set the threshold Th to the default high threshold Th. H .

[0082] If, in step S13, it is determined that the distance to the current destination is below a predetermined distance, the process proceeds to step S15, where the threshold setting unit 52 sets the threshold based on the battery temperature T. bat The threshold Th is set to a low threshold Th. L Additionally, in step S14, if it is determined that the time to reach the current destination is less than a predetermined time, step S15 is also entered, and the threshold setting unit 52 sets the threshold based on the battery temperature T. bat The threshold Th is set to a low threshold Th. L That is, when the current destination is a specific destination (S11: Yes), and when the distance from the current destination is less than a specified distance (S13: Yes), or when the distance from the current destination is less than a specified time, the threshold setting unit 52 will set the threshold based on the battery temperature T. bat The threshold Th is set to a low threshold Th. L .

[0083] As described above, when the threshold Th is set (maintained) to a high threshold Th in step S12 H Alternatively, in step S15, the threshold Th can be changed to a lower threshold Th. L Then, proceed to step S16. In step S16, the temperature management unit 53 controls the battery temperature T. bat Compare with a threshold Th to monitor battery temperature T bat Then, when the battery temperature T... batWhen the threshold Th is exceeded (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 battery 11 is maintained at a temperature below the threshold Th. Specifically, the threshold Th is set to a high threshold Th. H At that time, the temperature management unit 53 can control the battery temperature T. bat Battery 11 is cooled in a manner that maintains it within an appropriate temperature range. Furthermore, the threshold Th is changed to a lower threshold Th. L At that time, the temperature management unit 53 cools the battery 11 (degradation prevention cooling) to keep the battery temperature T bat Maintain at a low threshold Th L The following temperatures are those maintained at a lower temperature within a suitable temperature range.

[0084] Figure 6 This is a flowchart of the destination determination (S11). Here, the destination determination unit 51 will explain the situation where it performs destination determination with reference to the registered destination 17.

[0085] like Figure 6 As shown, in step S21, the destination determination unit 51 pre-designates all or part of the registered destination 17 as a specific destination based on the attributes of the registered destination 17. Here, as an example, the destination determination unit 51 pre-designates the registered destination 17 with labels (attributes) such as "home" and "workplace" as a specific destination.

[0086] It should be noted that "home" and "workplace" are typical examples of destinations where the electric vehicle 100 is likely to be parked for an extended period after arrival. For example, if the electric vehicle 100 is mainly used for commuting (movement between "home" and "workplace"), the electric vehicle 100 arriving at the "workplace" is likely to be parked for approximately 7 to 8 hours until the driver finishes work. Additionally, the electric vehicle 100 arriving at the "home" is likely to be parked for approximately 12 hours until the next day's work start time. Of course, the destination determination unit 51 can designate registered destinations 17 other than "home" and "workplace" as specific destinations.

[0087] In addition, there are cases where the registered destination 17 with the label of "home" is simply referred to as "home", and the registered destination 17 with the label of "workplace" is simply referred to as "workplace".

[0088] In step S22, the destination determination unit 51 determines whether the current destination is the registered destination 17. When a driver or other user sets a destination by selecting from the registered destination 17 in the navigation system 13, the destination determination unit 51 determines that the current destination is the registered destination 17. On the other hand, when a driver or other user sets a new destination by inputting an address or using a map displayed by the navigation system 13, the destination determination unit 51 determines that the current destination is not the registered destination 17. Furthermore, in this embodiment, when a driver or other user uses a map or other means to set a new destination that is substantially the same as the registered destination 17, such as their home or workplace, the destination determination unit 51 determines that the current destination is not the registered destination 17. That is, when a driver or other user selects a destination from the registered destination 17 in the navigation system 13, the destination determination unit 51 determines that the current destination is the registered destination 17.

[0089] In step S22, if the current destination is determined to be 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 has a label indicating "home" or "workplace". Then, if the registered destination 17 set as the current destination has a pre-specified label indicating "home" or "workplace", 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 does not have a pre-specified label indicating "home" or "workplace", 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.

[0090] That is, when the current destination is selected from the registered destinations 17, the destination determination unit 51 determines the destination based on the tag (attribute).

[0091] Furthermore, in step S22, if it is determined that the current destination is a newly set destination rather than the 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 a "home" or "workplace" that has been pre-designated as a specific destination. Specifically, the destination determination unit 51 determines whether the current destination is close to a home, etc., for example, based on whether the distance between the current destination and the home, etc., is below a pre-set distance threshold. Then, if it is determined that the current destination is close to the home, etc., 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 the home, etc., the process proceeds to step S25, where the destination determination unit 51 determines that the current destination is a general destination.

[0092] Figure 7This is another flowchart for destination determination (S11). Here, we will explain the case where the driver or others set a new destination in the navigation system 13, and the new destination is not close to the previously specified destination (home or workplace), and the destination determination unit 51 determines the destination by referring to the driving record 18.

[0093] like Figure 7 As shown, in step S31, the destination determination unit 51 pre-designates the driving record 18 that meets the conditions as a specific driving record. Specifically, the destination determination unit 51 refers to the "parking time" field of the driving record 18 and designates the driving record 18 with a "parking time" of a specified time (typically about 4 to 6 hours) or more as a specific driving record. That is, the specific driving record is the driving record 18 that ultimately becomes the specific destination.

[0094] Then, in step S32, the destination determination unit 51 determines whether the current driving route corresponds to the driving route of a specific driving record.

[0095] Specifically, the destination determination unit 51 obtains the current driving route guided by the navigation system 13. Then, the destination determination unit 51 determines whether the current driving route is consistent with the driving route of a specific driving record.

[0096] In addition, the navigation system 13 typically prepares multiple alternative routes for reaching the destination. Therefore, when the route that replaces the current route being guided by the navigation system 13 (hereinafter referred to as the alternative route) is consistent with the route in a specific driving record, the destination determination unit 51 can determine that the current route is substantially consistent with the route in the specific driving record.

[0097] Furthermore, even if the current driving route or alternative driving route is inconsistent with the driving route of a specific driving record, the destination determination unit 51 can determine that the current driving route is substantially consistent with the driving route of the specific driving record when they are mostly consistent or when the approximate direction of movement and distance of movement are common.

[0098] Furthermore, as described above, the destination determination unit 51 determines that the current driving route corresponds to the driving route of the specific driving record when the current driving route is consistent with or substantially consistent with the driving route of the specific driving record.

[0099] If it is determined in step S32 that the current driving route corresponds to a specific driving record, the process proceeds to step S33. In step S33, the destination determination unit 51 determines whether the current date, time, etc., correspond to the specific driving record.

[0100] For example, the destination determination unit 51 determines whether the current date and time match (or substantially match) the weekday / rest day category shown in the month, day, and weekday of a specific travel record. For example, the destination determination unit 51 determines whether the current date and time are included in the departure time period of that specific travel record. Additionally, for example, the destination determination unit 51 determines whether the estimated arrival time based on the current travel route is included in the arrival time period of that specific travel record. Then, when all or most of these conditions are met, the destination determination unit 51 determines that the current date and time corresponds to a specific travel record whose travel route matches. In this embodiment, for simplicity, when all these conditions are met—that is, when the current date and time match the weekday or rest day category indicated by the specific travel record and are included in the departure time period, and the current estimated arrival time is included in the arrival time period of the specific travel record—the destination determination unit 51 determines that the current date and time corresponds to a specific travel record whose travel route matches.

[0101] In step S33, if it is determined that the current date and time correspond to a specific driving record, 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 a specific driving record, or if it is determined in step S33 that the current date and time do not correspond to a specific driving record, the process proceeds to step S35, where the destination determination unit 51 determines that the current destination is a general destination.

[0102] Figure 8 This is another flowchart for destination determination (S11). Here, we will explain the following situation: when a driver or other person sets a new destination in the navigation system 13, and the newly set destination is not close to the previously specified destination (home or workplace) and the driving route is inconsistent with the previously specified driving record, the destination determination unit 51 refers to the driving record 18 to determine the destination.

[0103] like Figure 8 As shown, in step S41, the destination determination unit 51, based on multiple driving records 18, pre-determines combinations of month / day, weekday, and arrival time period where the "parking time" is a specified time (typically around 4 to 6 hours) or more. That is, the destination determination unit 51 pre-determines driving scenarios (month / day, weekday, and arrival time period) where the current destination is highly likely to become the specific destination. In this embodiment, the destination determination unit 51 determines the aforementioned driving scenario by summarizing various recorded items from a specific driving record.

[0104] In step S42, the destination determination unit 51 determines whether the current date and time matches the weekday / rest day category shown in the determined month, day, and weekday chart. Then, if it is determined in step S42 that the current date and time matches the weekday / rest day category shown in the determined month, day, and weekday chart, the process proceeds to step S43, where the destination determination unit 51 further determines whether the estimated arrival time of the current destination is included in the determined arrival time period. If it is determined in step S43 that the estimated arrival time of the current destination is included in the determined arrival time period, the process proceeds to step S44, where the destination determination unit 51 determines that the current destination is a specific destination.

[0105] On the other hand, if in step S42 it is determined that the current date and time are different from the weekday / rest day category shown in the determined month, day and weekday, or in step S43 it is determined that the estimated arrival time of the current destination is not included in the determined arrival time period, then step S45 is entered, and the destination determination unit 51 determines that the current destination is a general destination.

[0106] Furthermore, the destination determination unit 51 is capable of performing the above-mentioned functions. Figures 6-8 One or more destination decisions in the destination determination process. Figures 6-8 When the destination determination results conflict, for example, if the destination determination unit 51 determines that the current destination is a specific destination through any of these destination determinations, it can ultimately determine the current destination as the specific destination.

[0107] Figure 9 This is a flowchart of the cooling circuit switching process. Here, the cooling circuit switching control performed by the temperature management unit 53 when cooling the battery 11 in step S17 will be explained.

[0108] like Figure 9 As shown, in step S51, the temperature management unit 53 confirms the battery temperature T. bat Is the threshold Th a low threshold Th? L When the threshold Th is low. L In the case of this, proceeding to step S52, the temperature management unit 53 further adjusts the SOC of the battery 11 against its upper limit U. lim Compare them. Then, with SOC as the upper limit value U. lim Upon reaching the above, the process proceeds to step S53, where the temperature management unit 53 uses the second cooling circuit 22 to cool the battery 11. Thus, the temperature management unit 53 actively consumes the state of charge (SOC) of the battery 11 while simultaneously performing deterioration prevention cooling.

[0109] On the other hand, in step S51, the threshold Th is the high threshold Th. H In the case of, or in step S52, SOC is higher than the upper limit value Ulim If the temperature is low, proceed to step S54, where the temperature management unit 53 monitors the ambient air temperature T. atm With the first cooling water temperature T w1 Compare them.

[0110] In step S54, at the outside air temperature T atm The first cooling water temperature T w1 When the first cooling circuit 21 using the heat sink 31 substantially loses its cooling capacity, the process proceeds to step S53, where the temperature management unit 53 uses the second cooling circuit 22 to cool the battery 11. That is, the temperature management unit 53 has to consume the battery's state of charge (SOC) and lower the battery temperature T. bat It remains below the threshold Th.

[0111] In step S54, at the outside air temperature T atm Compared to the first cooling water temperature T w1 When the cooling capacity of the first cooling circuit 21 using the heat sink 31 is maintained at a low temperature, the process proceeds to step S55, where the temperature management unit 53 uses the first cooling circuit 21 to cool the battery 11. That is, the temperature management unit 53 cools the battery 11 with almost no power consumption (SOC) of the battery 11. bat It remains below the threshold Th.

[0112] Thus, at an outside air temperature T atm Compared to the first cooling water temperature T w1 When the temperature is low and the first cooling circuit 21 and the second cooling circuit 22 can be arbitrarily selected to prevent cooling degradation, the temperature management unit 53 maintains the upper limit of SOC U. lim The first cooling circuit 21 is used for hours, with the SOC at the upper limit U. lim The second cooling circuit 22 is used in the above cases. Furthermore, at an ambient air temperature T... atm The first cooling water temperature T w1 In order to prevent cooling degradation, when only the second cooling circuit 22 can be selected, the temperature management unit 53 uses the second cooling circuit 22 to cool the battery 11.

[0113] Additionally, when the threshold Th is set to a high threshold Th H In the scenario where the outside air temperature T atm Compared to the first cooling water temperature T w1 When the temperature is low, and the first cooling circuit 21 and the second cooling circuit 22 can be arbitrarily selected for cooling the battery 11, the temperature management unit 53 uses the first cooling circuit 21. Furthermore, when the ambient air temperature T... atm The first cooling water temperature T w1In the above context, when the second cooling circuit 22 is the only viable option for cooling the battery 11, the temperature management unit 53 uses the second cooling circuit 22 to cool the battery 11.

[0114] Figure 10 This is a schematic representation of the battery temperature T. bat A graph showing the progression of [something]. Here, Figure 10 (A) represents the vehicle speed V. Figure 10 (B) represents the output P of battery 11. bat Output P bat The value is positive when battery 11 is charging and negative when battery 11 is discharging. Figure 10 (C) indicates the SOC of battery 11. Figure 10 (D) represents the battery temperature T. bat .exist Figure 10 In the diagram, solid lines represent the shifts in the parameters described above in this embodiment, while dashed lines represent the shifts in the parameters described above in the comparative example. In the comparative example, the threshold Th is always set to a high threshold Th. H Examples of cooling systems that do not take measures to prevent deterioration.

[0115] It should be noted that, in Figure 10 The above describes a scenario where an electric vehicle 100 travels from a "workplace" or similar location to its "home," which is its specific destination, and then stops. Time t1 is the time when the distance to the "home" is less than a predetermined distance, or the time to reach the "home" is less than a predetermined time. Time t2 is the arrival time at the "home." Therefore, in this embodiment, the threshold Th is also set to a high threshold Th for period A1. H The period (normal cooling period). In this embodiment, period A2 is when the threshold Th changes to a lower threshold Th. L The period for deterioration prevention cooling is as follows. Moreover, period A3 is the period after arriving at one's own residence, which is the specific destination. Here, the cooling of battery 11 is provided by the second cooling circuit 22.

[0116] like Figure 10 As shown in (A), for simplicity, it is assumed that the electric vehicle moves from the workplace to its residence at a constant speed of 100 and stops. At this time, as Figure 10 (B) and Figure 10 As shown by the dashed line in (C), in the comparative example, battery 11 consumes a certain amount of electrical energy, and its SOC decreases. Thus, when consuming electrical energy, battery 11 heats up due to its internal resistance, etc., but when the battery temperature T... bat Exceeding threshold Th (high threshold Th) H When this occurs, battery 11 is cooled. Therefore, as... Figure 10As shown by the dashed line in (D), in the comparative example, during periods A1 and A2 when the electric vehicle 100 is in motion, the battery temperature T... bat Maintain at a high threshold Th H Then, when the electric vehicle 100 arrives at its home and parks, it takes a long time to cool down naturally.

[0117] Therefore, in the comparative example, the battery temperature T bat Within a suitable temperature range, but with prolonged periods of relatively high temperatures, even if battery 11 does not degrade in the short term, it can easily accelerate its degradation over the long term. Furthermore, as... Figure 10 As shown in (C), after battery 11 is fully charged and arrives at home, the SOC is higher than the upper limit U. lim High temperatures can significantly accelerate battery degradation in the long run.

[0118] In this embodiment, battery 11 consumes electrical energy, and the decrease in SOC is the same as in the comparative example. However, in this embodiment, at time t2, the threshold Th decreases from the high threshold Th. H Reduce to a low threshold Th L Deterioration prevention cooling is performed before reaching the residence. Additionally, a second cooling circuit 22 is used here for deterioration prevention cooling. Therefore, as... Figure 10 (B) and Figure 10 As shown by the solid line in (C), in this embodiment, after time t2, compared to the comparative example, the energy consumption of battery 11 increases, and the SOC decreases to the upper limit U before reaching the home. lim Then, as Figure 10 As shown by the solid line in (D), the threshold Th is changed to a lower threshold Th after time t2. L In this embodiment, the battery temperature T bat Cooled to a low threshold Th before reaching its own residence. L the following.

[0119] That is, in this embodiment, the battery 11 is cooled at the time when the electric vehicle 100 arrives at the residence, so that the battery temperature T bat It becomes a lower temperature within a suitable temperature range. As a result, in this embodiment, even after the electric vehicle 100 arrives at its residence, for example, and is parked until the next morning, long-term battery degradation 11 can be suppressed. Furthermore, as... Figure 10 As shown in (C), the SOC of battery 11 drops to the upper limit U. lim Therefore, it is particularly easy to suppress the degradation of battery 11 under long-term view.

[0120] As described above, the battery temperature management method of the above embodiment is as follows: The temperature of the battery 11 mounted on the electric vehicle 100 is obtained, and the temperature of the battery 11 (T...) is... bat When the temperature of battery 11 exceeds a preset threshold Th, the battery 11 is cooled, thereby reducing the temperature of battery 11 (T). bat The battery temperature is maintained below the threshold Th. In this battery temperature management method, it is determined whether the current destination of the electric vehicle 100 is a specific destination for which the expected continuous parking time is more than a specified time. If the current destination is a specific destination, the threshold Th is reduced.

[0121] Thus, if the threshold Th is lowered by identifying whether the destination (current destination) is a specific destination, the battery temperature T will be lower after reaching the destination. bat When the probability of a prolonged high-temperature state is high, battery 11 is cooled to keep the battery temperature T. bat Become the lower temperature within the appropriate temperature range (low threshold Th) L (The following temperature). As a result, it is possible to suppress battery degradation under long-term viewing conditions. Furthermore, compared to making the battery temperature T... bat Compared to cooling the battery 11 in a stable, lower-temperature manner, it can suppress drawbacks such as deterioration in power consumption and reduction in driving range. Furthermore, compared to cooling the battery to a lower temperature T after reaching the destination... bat Compared to the method of quickly cooling the battery 11 to a lower temperature, the battery temperature management control described above, which lowers the threshold Th during driving as described above, has the advantage of not worrying about the operating noise of the cooling system 12 and being able to use the driving airflow 34 to cool the battery 11.

[0122] In the battery temperature management method of the above embodiment, a specific destination is pre-specified from the registered destinations 17 registered in the navigation system 13. In the navigation system 13, it is determined 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.

[0123] Thus, if a specific destination is specified from the registered destinations 17 in the navigation system 13, it is easy and reliable to determine whether the current destination is the specific destination. Therefore, it is particularly easy to suppress battery degradation under long-term viewing conditions.

[0124] In the battery temperature management method described above, the registered destination, which is either one's own residence or workplace, is designated as a specific destination.

[0125] Home or workplace are typical examples of destinations where electric vehicles are likely to be parked for 100 hours after arrival, so if home or workplace is designated as a specific destination, it is particularly easy to suppress battery degradation under long-term perspective.

[0126] In the battery temperature management method of the above embodiments, when a 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. If the distance between the current destination set in the navigation system 13 and the home or workplace is below a preset distance threshold, the current destination is determined to be a specific destination.

[0127] In this way, it is preferable to determine (presume) a destination as a specific destination when the newly set destination, which was not selected from the registered destination 17, is close to the registered destination 17 designated as a specific destination and there is a high probability that the newly set destination is actually the designated specific destination. In this way, even if the destination is not selected from the registered destination 17 and is newly set, appropriate degradation prevention cooling can be performed.

[0128] In the battery temperature management method of the above embodiments, a driving record 18, including at least information related to the driving route and departure time, is stored in advance. The current driving route and the current date and time are compared with the driving record 18, i.e., the specific driving record, when the current driving route and the current date and time correspond to the specific driving record. When the current driving route and the current date and time correspond to the specific driving record, it is determined that the current destination is the specific destination corresponding to the specific driving record.

[0129] In this way, if the current destination is determined based on the driving record 18, appropriate deterioration prevention cooling can be performed in cases such as when a new destination is set and the destination is not close to the designated specific destination (home or workplace).

[0130] In the battery temperature management method of the above embodiments, the driving record 18 includes information related to the month, day and week, in addition to the driving route and departure time. When the current driving route corresponds to the driving route of a specific driving record, and the current date and time correspond to the departure time, month, day and week of the specific driving record, it is determined that the current destination is the specific destination.

[0131] In this way, if the current destination is determined based on the driving record 18, appropriate deterioration prevention cooling can be performed in cases such as when a new destination is set and the destination is not close to the designated specific destination (home or workplace).

[0132] In the battery temperature management method of the above embodiments, driving records 18 are pre-stored that establish a correspondence between the destination, month and day, weekday, arrival time at the destination (i.e., arrival time period), and parking time at the destination. Based on multiple driving records 18, combinations of month and day, weekday, and arrival time periods with a high frequency of parking time exceeding a specified time are pre-determined. Then, when the current date and time correspond to the determined month, day, and weekday, and the estimated arrival time of the current destination is included in the determined arrival time period, the current destination is determined to be a specific destination.

[0133] In this way, if the current destination is determined based on the driving record 18, then even if a new destination is set, and that destination is not close to the specified specific destination, and the driving route is inconsistent with the specific driving record, appropriate degradation prevention cooling can be performed.

[0134] In the battery temperature management method of the above embodiments, when the current destination is a specific destination, the threshold Th is reduced when the remaining distance to the current destination is less than a predetermined distance, or when the remaining time to the current destination is less than a predetermined time.

[0135] If the current destination is a specific destination, and the threshold Th is always set to a low threshold Th. L Degradation prevention cooling depends on the distance or time to the current destination, and may result in deterioration of power consumption and reduced driving range. Furthermore, degradation prevention cooling is implemented to prevent prolonged periods of high temperature after reaching the destination. In other words, degradation prevention cooling aims to reduce the battery temperature T upon arrival at the destination. bat For low threshold Th L Therefore, even if the current destination is a specific destination, it is not necessary to perform degradation prevention cooling at all times while driving. Therefore, as mentioned above, if degradation prevention cooling is performed by lowering the threshold Th before reaching the destination, the problems of deterioration of power consumption and reduction of driving range can be minimized, and degradation prevention cooling can be performed appropriately.

[0136] In the battery temperature management method described above, the battery 11 is cooled by water cooling, which circulates cooling water in the battery 11, or by air cooling, which blows air into the battery 11.

[0137] Thus, deterioration prevention cooling can be achieved through water cooling, air cooling, or a combination of both.

[0138] In the above embodiment, the electric vehicle 100 includes: a first cooling circuit 21 that circulates cooling water (first cooling water) between the battery 11 and a radiator 31 cooled by outside air; and a second cooling circuit 22 that circulates cooling water (second cooling water) between the battery 11 and a cooler 42 cooled by refrigerant from an air conditioning system 41. Furthermore, in the battery temperature management method of the above embodiment, the state of charge (SOC) of the battery 11 is compared with a preset upper limit value U. lim In comparison, when the threshold Th is reduced, the state of charge (SOC) is lower than the upper limit U. lim During the hour, the battery 11 is cooled through the first cooling circuit 21, reducing the threshold Th while maintaining the maximum state of charge (SOC) U. lim At this time, the battery 11 is cooled by the second cooling circuit 22.

[0139] From a long-term perspective, the degradation of battery 11 occurs at battery temperature T. bat The progress is greatest when the state with a high SOC is maintained. Therefore, as mentioned above, when the SOC is at its upper limit U... lim In the above case, if the second cooling circuit 22 is used to actively consume the electrical energy of the battery 11, it is particularly easy to suppress the degradation of the battery under long-term view.

[0140] The battery temperature management device in the above embodiment acquires the temperature (T) of the battery 11 mounted on the electric vehicle 100. bat ), at the temperature of battery 11 (T) bat When the temperature of battery 11 exceeds a preset threshold Th, the battery 11 is cooled, thereby reducing the temperature of battery 11 (T). bat The battery temperature management device (controller 14) maintains the temperature below a threshold Th. Furthermore, the battery temperature management device (controller 14) includes: a destination determination unit 51, which determines whether the current destination of the electric vehicle 100 is a specific destination for which a predetermined period of continuous parking is expected; and a threshold setting unit 52, which lowers the threshold Th when the current destination is a specific destination.

[0141] In this way, the controller 14 identifies whether the destination (current destination) is a specific destination and lowers the threshold Th, so that the battery temperature T decreases after reaching the destination. bat When there is a high probability that the high temperature condition will persist for an extended period, battery 11 should be cooled to keep the battery temperature T. bat Become the lower temperature within the appropriate temperature range (low threshold Th) L (The following temperature). As a result, controller 14 is able to suppress the degradation of battery 11 under long-term viewing conditions. Additionally, with the battery temperature T... batCompared to consistently cooling the battery 11 to a lower temperature, this method can suppress problems such as deteriorating power consumption and reduced driving range. Furthermore, compared to cooling the battery to a lower temperature T after reaching the destination... bat Compared to the method of quickly cooling the battery 11 to a lower temperature, the battery temperature management control described above, which lowers the threshold Th during driving as described above, has the advantage of not worrying about the operating noise of the cooling system 12 and being able to use the driving airflow 34 to cool the battery 11.

[0142] The embodiments of the present invention have been described above. However, the structures described in the above embodiments are only a part 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, comprising acquiring the temperature of a battery mounted on an electric vehicle, and when the battery temperature is above a preset threshold, maintaining the battery temperature below the threshold by cooling the battery, characterized in that... Determine whether the current destination of the electric vehicle is a specific destination for which the expected continuous parking time exceeds a specified period. When the current destination is the specific destination, the threshold is lowered.

2. The battery temperature management method according to claim 1, characterized in that, The specific destination is pre-specified from the registered destinations registered in the navigation system. In the navigation system, the current destination is determined to be the specific destination based on whether the registered destination designated as the specific destination is set as the current destination.

3. The battery temperature management method according to claim 2, characterized in that, The registered destination that will be registered as one's own residence or workplace will be designated as the specific destination.

4. The battery temperature management method according to claim 1, characterized in that, When a home or workplace is registered in the 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. When the distance between the current destination set in the navigation system and the home or workplace is below a preset distance threshold, the current destination is determined to be the specific destination.

5. The battery temperature management method according to claim 1, characterized in that, Pre-save driving records, including at least information related to the driving route and departure time. The current driving route and current date and time are compared with the driving record, i.e., the specific driving record, when the destination was previously the specific destination. When the current driving route and the current date and time correspond to the specific driving record, it is determined that the current destination is the specific destination corresponding to the specific driving record.

6. The battery temperature management method according to claim 5, characterized in that, In addition to the driving route and departure time, the driving record also includes information related to the month, day, and week of the week. When the current driving route corresponds to the driving route of the specific driving record, and the current date and time correspond to the departure time period, month, day, and week of the specific driving record, the current destination is determined to be the specific destination.

7. The battery temperature management method according to claim 1, characterized in that, Pre-save driving records that establish a correspondence between the destination, month and day, day of the week, the time period for arrival at the destination (i.e., the arrival time period), and the parking time at the destination. Based on multiple driving records, a combination of month, day of the week, and arrival time period that frequently occurs at or above the specified time is pre-determined. When the current date and time correspond to the determined month, day and week, and the estimated arrival time to the current destination is included in the determined arrival time period, the current destination is determined to be the specific destination.

8. The battery temperature management method according to claim 1, characterized in that, When the current destination is the specific destination, the threshold is lowered when the remaining distance to the current destination is less than a specified distance or when the remaining time to the current destination is less than a specified time.

9. The battery temperature management method according to claim 1, characterized in that, The battery is cooled by either water cooling, which involves circulating cooling water within the battery, or by air cooling, which involves blowing air into the battery.

10. The battery temperature management method according to claim 1, characterized in that, The electric vehicle has: a first cooling circuit that circulates cooling water between the battery and a radiator cooled by outside air; and a second cooling circuit that circulates cooling water between the battery and a radiator cooled by refrigerant from an air conditioning system. The charging rate of the battery is compared with a preset upper limit value. When the threshold is lowered, and the charging rate is less than the upper limit, the battery is cooled by the first cooling circuit. When the threshold is lowered, the battery is cooled by the second cooling circuit when the charging rate is above the upper limit.

11. A battery temperature management device, comprising acquiring the temperature of a battery mounted on an electric vehicle, and when the battery temperature is above a preset threshold, maintaining the battery temperature below the threshold by cooling the battery, characterized in that, have: The destination determination unit determines whether the current destination of the electric vehicle is a specific destination for which the expected continuous parking time is more than a specified time. The threshold setting unit lowers the threshold when the current destination is the specific destination.

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