Battery temperature control method and battery temperature control device

Abstract

In this invention, an expected time at which the temperature of a battery must be in a desired temperature range is predicted, or information pertaining to the expected time is acquired, and if the temperature of the battery is lower than the desired temperature range, a charge–discharge control of the battery is repeated as a battery warmup control prior to the expected time, thereby raising the temperature of the battery to be in the desired temperature range at the expected time.

Description

[Technical Field]

[0001] The present invention relates to a battery temperature control method and a battery temperature control device for controlling the temperature of a drive battery that is a drive source for a vehicle. This application claims priority based on Japanese Patent Application No. 2021-203322 filed on December 15, 2021, and for designated states where incorporation by reference of documents is permitted, the contents of the above application are incorporated by reference into this application and made part of the description of this application. [Background technology]

[0002] A known power supply control system for a mobile body includes a power storage device mounted on the mobile body and chargeable by an external power supply facility, a temperature adjustment unit for adjusting the temperature of the power storage device, and a temperature control unit that monitors the temperature of the power storage device and controls the temperature of the power storage device using the temperature adjustment unit (Patent Document 1). The temperature control unit predicts the next charging time for the power storage device and the temperature of the power storage device at the next charging time based on installation information of external power supply facilities along the travel route of the mobile body and the power storage state of the power storage device. Furthermore, the temperature control unit adjusts the temperature of the power storage device using the temperature adjustment unit before the next charging time based on these prediction results. The temperature adjustment unit includes, for example, an air-cooled or water-cooled heating unit using a heater or the like, or an air-cooled or water-cooled cooling unit using a fan or refrigeration cycle or the like. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-13726 Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional technology, the battery is heated using a heater with limited heating capacity, so even if the battery is heated in advance, it is difficult to heat the battery to the desired temperature range by the time of the next charging period, when the battery needs to be heated up.

[0005] The problem to be solved by the present invention is to provide a battery temperature control method and a battery temperature control device that can raise the temperature of a battery to a desired temperature range by the time the battery needs to be heated. [Means for solving the problem]

[0006] The present invention solves the above problem by predicting or obtaining information on a scheduled time when the battery temperature needs to be within a desired temperature range, and if the battery temperature is lower than the desired temperature range, repeating battery charge and discharge control as battery temperature increase control before the scheduled time, thereby raising the battery temperature to the desired temperature range at the scheduled time. [Effects of the Invention]

[0007] According to the present invention, the battery is heated by self-heating, so that the battery can be heated to a desired temperature range by the time the battery needs to be heated. [Brief explanation of the drawings]

[0008] [Figure 1] Fig. 1(A) is a schematic diagram of an electric vehicle according to this embodiment, and Fig. 1(B) is an example of a control block diagram showing the main configuration of a control system of the electric vehicle shown in Fig. 1(A). [Figure 2] 2A and 2B are flowcharts showing the procedure of battery temperature control according to this embodiment. [Figure 3] Fig. 3(A) is a diagram showing a subroutine of step S6 shown in Fig. 2(A), and Fig. 3(B) is a diagram showing a subroutine of step S25 shown in Fig. 2(B). [Figure 4]FIG. 4 is a diagram for explaining the relationship between the battery temperature and the temperature of the battery, which is controlled before the vehicle starts to travel. [Figure 5] FIG. 5 is a diagram for explaining the relationship between the battery temperature control performed before the start of high-load operation and the battery temperature. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a battery temperature control method and a battery temperature control device according to the present invention will be described with reference to the accompanying drawings.

[0010] FIG. 1(A) is a schematic diagram of an electric vehicle 100 according to this embodiment. In this embodiment, the electric vehicle 100 will be described as a so-called series hybrid vehicle equipped with an engine 1 (internal combustion engine) as a power generation device, a power generation motor (hereinafter referred to as generator 2), and a motor 4 that generates driving force for driving the electric vehicle 100 using electric power from the generator 2 or a battery 3. As shown in FIG. 1(A), the electric vehicle 100 includes the engine 1, the generator 2, the battery 3, the motor 4, a generator inverter 5, a motor inverter 6, a power delivery module 7, a battery junction box 8, a charging plug 9, and a battery controller 10. Of these, for example, the battery controller 10 may constitute a battery temperature control device according to this embodiment of the present invention.

[0011] The engine 1 is connected to the generator 2 via gears (not shown), and generates power for the generator 2 to generate electricity in response to commands from an engine controller 11 (see FIG. 1(B)), which will be described later, and transmits the power to the generator 2. That is, the engine 1 is used in the electrically powered vehicle 100 as a drive source for the generator 2 to generate electricity.

[0012] The generator 2 is configured to be able to crank the engine 1 when it is started and to perform motoring to rotate the engine 1 by powering it, in response to commands from a generator controller 12 (see FIG. 1(B)) described later.

[0013] The battery 3 is a high-voltage battery, such as a lithium-ion secondary battery, and includes a power generating element having a positive electrode including a positive electrode active material layer containing a positive electrode active material capable of absorbing and releasing lithium ions, a negative electrode including a negative electrode active material layer containing a negative electrode active material capable of absorbing and releasing lithium ions, and an electrolyte layer interposed between the positive electrode active material layer and the negative electrode active material layer and containing an electrolyte as a main component.

[0014] The positive electrode active material is not particularly limited, but examples thereof include layered rock salt active materials (e.g., LiCoO2), spinel active materials (e.g., LiMn2O4), olivine active materials (e.g., LiFePO4), and Si-containing active materials (e.g., Li2FeSiO4), all of which were known at the time of filing of this application. Examples of oxide active materials other than those mentioned above include Li4Ti5O12. Composite oxides containing lithium and nickel are preferably used, and more preferably Li(Ni-Mn-Co)O2 and those in which a portion of the transition metal is substituted with another element (NMC composite oxide). As mentioned above, NMC composite oxides also include composite oxides in which a portion of the transition metal element is substituted with another metal element. In this case, other elements include Ti, Zr, Nb, W, and P. Furthermore, sulfur-based positive electrode active materials may also be used. The sulfur-based positive electrode active material may be particles or thin films of organic sulfur compounds or inorganic sulfur compounds, and may be any material capable of releasing lithium ions during charging and absorbing lithium ions during discharging by utilizing the oxidation-reduction reaction of sulfur. Note that the above-described positive electrode active material is merely an example, and in this embodiment, any material known at the time of filing of this application may be used as the positive electrode active material.

[0015] Also, in the present embodiment, the negative electrode active material layer contains a negative electrode active material having a potential of 0.5 V or more with respect to the equilibrium potential in the reaction between lithium metal and lithium ions. Examples of the negative electrode active material include lithium titanate (LTO) and niobium titanium-based oxide (NTO). These negative electrode active materials may be used alone or in combination of two or more. In addition, negative electrode active materials other than those described above may be used. Also, in the present embodiment, the negative electrode may be a lithium metal such that the negative electrode active material layer dissolves during discharge. For example, the battery 3 may be configured to include a power generation element in which the negative electrode active material layer, the electrolyte layer, and the positive electrode active material layer are laminated in this order during charging. In the case of such a configuration, in the negative electrode (also referred to as a lithium full-deposition type electrode), the lithium deposited during charging can be dissolved during discharge.

[0016] Also, in the present embodiment, the electrolyte layer may contain a solid electrolyte as a main component, that is, the battery 3 may be an all-solid-state lithium-ion secondary battery using a solid electrolyte. Examples of the solid electrolyte include sulfide solid electrolytes and oxide solid electrolytes. Examples of the sulfide solid electrolyte include, for example, a Li-P-S-based solid electrolyte (for example, Li7P3S11) called LPS. Also, as the sulfide solid electrolyte, for example, LGPS represented by Li(4-x)Ge(1-x)PxS4 (x satisfies 0 < x < 1) may be used. Examples of the oxide solid electrolyte include, for example, compounds having a NASICON-type structure. An example of a compound having a NASICON-type structure includes a lithium lanthanum zirconium-containing composite oxide (LLZO), a compound represented by the general formula Li1+xAlxGe2-x(PO4)3 (0 ≦ x ≦ 2) (LAGP), a compound represented by Li1+2xZr2-xCax(PO4)3 (LZCP), a compound represented by the general formula Li1+xAlxTi2-x(PO4)3 (0 ≦ x ≦ 2) (LATP), and the like. Also, as the oxide solid electrolyte, a garnet-type solid electrolyte (for example, Li7La3Zr2O12) called LLZ may be used.

[0017] The battery 3 is not limited to an all-solid-state lithium-ion secondary battery, but may be a lithium secondary-ion battery composed of an electrode composite layer containing a solid electrolyte and an electrolyte layer using an organic electrolyte solution. For example, in the battery 3, the positive electrode active material layer may include a positive electrode composite layer formed by mixing an electrode composite responsible for the adhesion of the electrode with a positive electrode active material to form a layer, and the negative electrode active material layer may include a negative electrode composite layer formed by mixing an electrode composite responsible for the adhesion of the electrode with a negative electrode active material to form a layer. For example, the above-mentioned solid electrolyte materials can be used for the positive electrode composite layer and / or the negative electrode composite layer.

[0018] Although not shown, a voltage sensor connected between the positive and negative electrodes of the battery 3 to detect the voltage of the battery 3, a current sensor connected to the positive electrode of the battery 3 to detect the charge / discharge current of the battery 3, and a temperature sensor to detect the temperature of the battery 3 are provided around the battery 3. The voltage of the battery 3 detected by the voltage sensor, the charge / discharge current of the battery 3 detected by the current sensor, and the temperature of the battery 3 detected by the temperature sensor are output to the battery controller 10.

[0019] The motor 4 generates driving force using AC power supplied from the motor inverter 6, and the generated driving force is transmitted to the driving wheels FR, FL via a speed reducer (not shown). When the electric vehicle 100 is decelerating or coasting, regenerative driving force is transmitted from the driving wheels FR, FL to the motor 4, causing the motor 4 to rotate. As the motor 4 rotates, AC power is output from the motor 4 to the motor inverter 6.

[0020] The generator inverter 5 is connected to the generator 2, the battery 3, and the motor inverter 6. In response to a command from the generator controller 12, the generator inverter 5 converts the AC power generated by the generator 2 into DC power and outputs it to the battery 3 or the motor inverter 6. In response to a command from the generator controller 12, the generator inverter 5 also converts the DC power supplied from the battery 3 into AC power and outputs it to the generator 2.

[0021] In response to a command from a motor controller 13 (see FIG. 1(B)), which will be described later, the motor inverter 6 converts DC power supplied from the battery 3 or the generator inverter 5 into AC power and outputs it to the motor 4. The motor inverter 6 also converts AC power supplied from the motor 4 into DC power based on a command from the motor controller 13. The converted DC power is output to the battery 3 via the power delivery module 7 and the battery junction box 8.

[0022] The power delivery module 7 is provided between the battery 3 and the generator inverter 5 and the motor inverter 6, and manages charging power to and discharging power from the battery 3 in response to commands from a battery controller 10. In this embodiment, the electric vehicle 100 is configured to be able to charge the battery 3 from an external power supply facility 17 (see FIG. 1(B)) provided outside the electric vehicle 100. As shown in FIG. 1(A), the power delivery module 7 is connected to a charging plug 9 by a charging cable. The charging plug 9 has a shape that can be fitted into a connector of the external power supply facility 17, and the charging plug 9 is configured to be connectable to the external power supply facility. The power delivery module 7 may include a rectifier circuit for rectifying AC voltage from the external power supply facility 17, a smoothing circuit that smooths the rectified voltage, and a DC-DC converter that converts the smoothed DC voltage to a predetermined voltage. The charging method for charging the battery 3 from the external power supply equipment 17 is not particularly limited, but examples of the charging method that can be used include the CHAdeMO (registered trademark) standard, which transmits and receives control signals related to charging via CAN (Controller Area Network) communication, and other standards. The charging cable has communication signal lines (such as signal lines for CAN communication) and power supply lines that comply with each standard.

[0023] The battery junction box 8 has a main relay (not shown) for establishing or breaking electrical connection between the battery 3 and the generator inverter 5 and the motor inverter 6. The main relay is set to an open or closed state in response to a command from the battery controller 10, thereby electrically connecting or breaking electrical connection between the battery 3 and the generator inverter 5 and the motor inverter 6.

[0024] The battery controller 10 is configured as an electronic control unit comprising a computer equipped with hardware and software. The computer of the battery controller 10 is configured with a ROM (Read Only Memory) for managing the state of the battery 3, a CPU (Central Processing Unit) for executing programs stored in the ROM, and a RAM (Random Access Memory) that functions as an accessible storage device. Note that, as the operating circuit, an MPU (Micro Processing Unit), a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), etc. can be used instead of or in addition to the CPU.

[0025] The battery controller 10 manages the state of charge (SOC) of the battery 3. For example, the battery controller 10 calculates the current SOC corresponding to the current voltage of the battery 3 based on a map showing the correlation between the SOC and the voltage. The battery controller 10 outputs battery information including the current SOC to the vehicle controller 14. The battery controller 10 also executes charge control or discharge control of the battery 3 in response to a command from the vehicle controller 14 to drive the electric vehicle 100. In the following description, for convenience, the charge control and discharge control of the battery 3 will be referred to as "charge and discharge control." The battery controller 10 also calculates the internal resistance of the battery 3 based on the temperature and SOC of the battery 3, and calculates the input and output power of the battery 3 based on the temperature, internal resistance, SOC, and charge and discharge power of the battery 3. The battery controller 10 outputs the input and output power of the battery 3 to the vehicle controller 14. In this embodiment, the above-described method for calculating the state of charge of the battery 3, the method for controlling charging and discharging to drive the electric vehicle 100, and the method for calculating the inputtable power and output power of the battery 3 are not particularly limited, and any of the methods known at the time of filing of this application can be applied to the battery controller 10.

[0026] The battery controller 10 also manages the temperature of the battery 3. In response to a command from the vehicle controller 14 or the temperature of the battery 3, the battery controller 10 operates an air-cooled or water-cooled cooling system (not shown) that uses a fan, a refrigeration cycle, or the like to cool the battery 3. In this embodiment, the battery controller 10 also repeatedly executes charge / discharge control of the battery 3 to raise the temperature of the battery 3. During charging and discharging of the battery 3, a charge / discharge current flows through the internal resistance of the battery 3, generating heat based on the internal resistance and the charge / discharge current. In addition to the charge / discharge control for driving the electric vehicle 100, the battery controller 10 repeatedly executes charge / discharge control of the battery 3 to raise the temperature of the battery 3, thereby generating heat in the battery 3. In the following description, for convenience, the charge current and discharge current flowing through the internal resistance of the battery 3 will be referred to as "charge / discharge current." Details of the temperature-raising control by the battery controller 10 will be described later.

[0027] FIG. 1(B) is a control block diagram showing the main configuration of the control system of the electric vehicle 100 shown in FIG. 1(A). In the block diagram shown in FIG. 1(B), blocks similar to those in FIG. 1(A) are assigned the same reference numerals as those in FIG. 1(A). As shown in FIG. 1(B), the control system of the electric vehicle 100 includes a battery controller 10, an engine controller 11, a generator controller 12, a motor controller 13, and a vehicle controller 14. Like the battery controller 10, the engine controller 11, the generator controller 12, the motor controller 13, and the vehicle controller 14 are configured as electronic control units consisting of computers equipped with hardware and software. Each computer is configured with a CPU as an operating circuit and RAM as an accessible storage device. FIG. 1(B) also shows an air conditioning system 15 and a navigation system 16 as systems mounted on the electric vehicle 100 and capable of communicating with the above control system. FIG. 1(B) also shows an external power supply facility 17 provided outside the electric vehicle 100 as a facility capable of charging the battery 3.

[0028] The engine controller 11 adjusts the amount of intake air by the throttle actuator and the amount of fuel injected by the injector so that the operating point of the engine 1 (engine torque and engine speed) approaches the engine torque command value and engine speed command value input from the vehicle controller 14.

[0029] The generator controller 12 performs switching control on the generator inverter 5 according to the rotation speed detection value and voltage state of the generator 2 so that the generator rotation speed matches the generator rotation speed command value input from the vehicle controller 14.

[0030] The motor controller 13 performs switching control on the motor inverter 6 according to the state of the motor 4, such as the rotation speed and voltage, so that the traveling motor torque of the motor 4 achieves the motor torque command value input from the vehicle controller .

[0031] The air conditioning system 15 is a system for adjusting the temperature, humidity, air volume, air quality, etc., in the passenger compartment of the electric vehicle 100, and is a system that includes an air conditioner. The air conditioning system 15 according to this embodiment has a timer air conditioning function that performs air conditioning in the passenger compartment according to a desired schedule. When the occupant inputs the timer air conditioning settings via a display provided on the electric vehicle 100, the timer air conditioning information input by the occupant is input to the air conditioning system 15. The timer air conditioning information includes the scheduled departure time of the electric vehicle 100, the set temperature of the air conditioner, etc. The air conditioning system 15 operates the air conditioner so that the temperature in the passenger compartment reaches the set temperature by the scheduled departure time. The air conditioning system 15 also outputs the timer air conditioning information to the vehicle controller 14.

[0032] The navigation system 16 is equipped with a Global Navigation System (GNSS) receiver and acquires the current location of the electric vehicle 100 from a positioning device that receives radio waves from multiple navigation satellites to measure the current location of the electric vehicle 100, and acquires map information indicating the current location of the electric vehicle 100 from a map database (not shown). The navigation system 16 sets a driving route to a destination input by the occupant and provides route guidance to the occupant along the set driving route. The navigation system 16 also predicts the driving conditions of the electric vehicle 100 while it is traveling along the driving route based on the road width, gradient, road surface conditions, etc. of the driving route of the electric vehicle 100. The driving conditions of the electric vehicle 100 include information such as the vehicle speed of the electric vehicle 100 and the gradient of the road on which it is traveling. The navigation system 16 outputs driving route information including the current location, driving route, and driving conditions of the electric vehicle 100 to the vehicle controller 14. Furthermore, if an external power supply facility 17 that can be used by the electric vehicle 100 is installed on the travel route, the travel route information includes installation information of the external power supply facility 17.

[0033] The external power supply equipment 17 is configured as a charging station that is installed, for example, at a commercial facility, public facility, or the like along the travel route of the electric vehicle 100, and that includes a charger (not shown) that is connected to a commercial power source. The external power supply equipment 17 may also be a charging power source or the like installed in a user's parking lot, and charging of the battery 3 can be started by connecting the external power supply equipment 17 installed in such a charging location to a connection port (connection port provided with the charging plug 9) of the electric vehicle 100 using a charging cable. When the external power supply equipment 17 and the charging plug 9 are electrically connected, various pieces of information related to charging are exchanged between the external power supply equipment 17 and the vehicle controller 14 via communication signal lines included in the charging cable. Examples of information output from the external power supply equipment 17 to the vehicle controller 14 include external power supply equipment information of the external power supply equipment 17, including the rated output current and output power, and information calculated by the external power supply equipment 17 about the required full charge time required for the battery 3 to be fully charged. In this embodiment, the charging method of the external power supply equipment 17 is not particularly limited, and may be either normal charging or rapid charging. As will be described later, in this embodiment, when the external power supply equipment 17 and the electric vehicle 100 are connected, the battery 3 is repeatedly charged and discharged by controlling the temperature of the battery 3. Therefore, it is preferable that the external power supply equipment 17 is configured to include a charger / discharger capable of charging and discharging, rather than a charger. An example of such external power supply equipment 17 is a V2H (Vehicle to Home) charging equipment.

[0034] The vehicle controller 14 calculates a motor torque command value and a motor rotation speed for the motor 4 based on an accelerator opening amount corresponding to an accelerator pedal operation amount by the driver detected by an accelerator pedal sensor (not shown) and the vehicle speed of the electric vehicle 100 detected by a vehicle speed sensor (not shown). The vehicle controller 14 outputs the calculated motor torque command value to the motor controller 13.

[0035] The vehicle controller 14 also calculates the output power of the motor 4 based on the rotation speed, voltage, and motor torque command value of the motor 4. The vehicle controller 14 calculates a target power generation level for power generation using the engine 1 based on the output power of the motor 4 and the state of charge of the battery 3. The vehicle controller 14 also calculates an engine torque command value and an engine speed command value for the engine 1 based on the state of charge of the battery 3, sound and vibration performance, and efficiency of the engine 1, while satisfying the calculated target power generation level. The vehicle controller 14 outputs the calculated engine torque command value and engine speed command value to the engine controller 11. The vehicle controller 14 also calculates a generator speed command value according to the engine speed command value, and outputs the calculated generator speed command value to the generator controller 12.

[0036] Furthermore, in this embodiment, the vehicle controller 14 predicts the scheduled time when the temperature of the battery 3 needs to be within the desired temperature range. When the vehicle controller 14 predicts the scheduled time when the temperature of the battery 3 needs to be within the desired temperature range, it outputs information about the predicted scheduled time to the battery controller 10. In this embodiment, the scheduled time will be described using, as examples, the scheduled time when the electric vehicle 100 starts traveling (hereinafter referred to as the scheduled traveling start time) and the scheduled time when the output power of the battery 3 needs to be equal to or greater than a predetermined power in order to travel the electric vehicle 100 (hereinafter referred to as the scheduled high-load operation start time). The desired temperature range will be described later.

[0037] The vehicle controller 14 predicts the scheduled start time of the electric vehicle 100 based on the timer air conditioning information input from the air conditioning system 15. For example, the vehicle controller 14 predicts the scheduled departure time included in the timer air conditioning information as the scheduled start time of the electric vehicle 100. The vehicle controller 14 also predicts the scheduled start time of the electric vehicle 100 based on the required full charge time input from the external power supply equipment 17. For example, the vehicle controller 14 predicts the time after the required full charge time has elapsed from the current time as the scheduled start time of the electric vehicle 100.

[0038] Furthermore, the vehicle controller 14 predicts the scheduled start time of high-load operation of the electric vehicle 100 based on the driving route information input from the navigation system 16. For example, the vehicle controller 14 predicts whether the electric vehicle 100 will travel through a point where the driving force of the motor 4 will be higher than a reference driving force (hereinafter referred to as a high-load operation start point), such as a mountain road, a climbing lane on an expressway, or a merging point on an expressway, based on the current location, driving route, and driving route information of the electric vehicle 100 included in the driving route information. If the vehicle controller 14 predicts that the electric vehicle 100 will travel through a high-load operation start point, it predicts the time when the electric vehicle 100 will pass that point as the scheduled start time of high-load operation. The reference driving force is a driving force set based on the driving force of the motor 4 when the electric vehicle 100 travels on flat ground.

[0039] Next, a temperature control method for the battery 3 executed by the battery controller 10 will be described with reference to Figures 2 and 3. Figures 2(A) and 2(B) are flowcharts showing the procedure for battery temperature control according to this embodiment. Figure 3(A) is a diagram showing a subroutine of step S6 shown in Figure 2(A), and Figure 3(B) is a diagram showing a subroutine of step S25 shown in Figure 2(B). Each process shown in the flowcharts of Figures 2(A) and 2(B) is executed by the battery controller 10.

[0040] In step S1, the battery controller 10 starts up the battery 3. In step S2, the battery controller 10 determines whether or not the battery 3 is being charged in the electric vehicle 100 that is stopped. For example, if the battery controller 10 can acquire external power supply equipment information about the external power supply equipment 17 from the vehicle controller 14, the battery controller 10 determines that the battery 3 is being charged. If the battery controller 10 makes a positive determination, the process proceeds to step S3, and if the battery controller 10 makes a negative determination, the process proceeds to step S21 shown in FIG. 2(B).

[0041] In step S3, the battery controller 10 acquires battery information about the battery 3. The battery information includes at least the current temperature (T c ), and the heat capacity (C) of the battery 3. The heat capacity of the battery 3 is the heat capacity (unit: joule [J] / kelvin [K]) required to raise the temperature of the battery 3 by 1°C. The heat capacity of the battery 3 is pre-stored as a known value in a storage device such as a ROM, for example.

[0042] In step S4, the battery controller 10 calculates the current temperature (T c ) with the desired temperature range for normal operation, and determines whether the current temperature of battery 3 is lower than the desired temperature range for normal operation. When a lithium-ion secondary battery is used as battery 3 as in this embodiment, charging in a high-temperature environment may degrade the charge capacity of battery 3 and shorten the battery life of battery 3. Generally, lithium precipitation in a lithium-ion secondary battery increases with decreasing temperature and increasing charging current. Therefore, charging current is significantly limited in low-temperature environments. The desired temperature range for normal operation is a temperature range set based on the temperature characteristics of such a lithium-ion secondary battery. For example, the lower limit temperature is set to a temperature at which the charging current is equal to or greater than a predetermined reference current value, and the upper limit temperature is set to the highest temperature within the temperature range that can suppress deterioration of battery 3. The desired temperature range for normal operation is pre-stored as a known value in a storage device such as a ROM. If the battery controller 10 makes a positive determination, the process proceeds to step S5. If the battery controller 10 makes a negative determination, the process proceeds to step S11.

[0043] In step S5, the battery controller 10 receives the scheduled travel start time (t s1 ) information is acquired. The scheduled start time is, for example, the current time (t c) until the full charge time required for the battery 3 to be fully charged by the external power supply equipment 17 has elapsed. When the processing of step S5 is completed, the process proceeds to step S6. When the process proceeds to step S6, the process proceeds to step S41 of the subroutine shown in FIG. 3(A), where the time required to heat the battery 3 to the desired temperature range in normal operation (heat-up time) is calculated.

[0044] In step S41, the battery controller 10 determines the target temperature (T t1 ) is set. The target temperature of the battery 3 in this step is not particularly limited as long as it is within a desired temperature range in normal operation. For example, the battery controller 10 sets the lower limit temperature of the desired temperature range in normal operation as the target temperature of the battery 3.

[0045] In step S42, the battery controller 10 sets the target temperature (T t1 ) and the current temperature of battery 3 (T c ) and the temperature difference between the battery 3 temperature rise temperature (ΔT1=T t1 -T c ) is calculated.

[0046] In step S43, the battery controller 10 calculates the current temperature of the battery 3 (T c ) and the current state of charge (SOC) of the battery 3, the internal resistance (R) of the battery 3 is calculated. For example, the battery controller 10 calculates the internal resistance corresponding to the current temperature of the battery 3 (R=f(SOC, T)) based on a map showing the correlation between temperature and state of charge. c It is assumed that the battery controller 10 calculates the state of charge of the battery 3 in advance from the voltage of the battery 3, but the timing of calculating the state of charge is not particularly limited as long as it is calculated before the internal resistance is calculated, and the state of charge of the battery 3 may be calculated at any of the steps described above.

[0047] In step S44, the battery controller 10 predicts the charge / discharge current that will flow through the internal resistance of the battery 3 while repeatedly executing charge / discharge control of the battery 3 as the temperature increase control of the battery 3. In this embodiment, the battery controller 10 calculates the minimum charge / discharge current of the battery 3, and predicts the time average current per predetermined time of the minimum charge / discharge current as the charge / discharge current that will flow through the internal resistance while the temperature increase control is being executed. The minimum charge / discharge current is a current that is smaller than the limit values ​​(corresponding to the "first to third limit values" of the present invention) of the charge / discharge current of the battery 3 that are determined due to at least one of the constraints of the electric vehicle 100 and the constraints of the environment in which the electric vehicle 100 is placed. In step S44, the charge / discharge current of the battery 3 that is determined due to the constraints of the electric vehicle 100 is calculated based on the charge / dischargeable power of the battery 3 (I batt ) The charge / discharge current of the battery 3, which is determined due to the constraints of the environment in which the electric vehicle 100 is placed, is the charge / discharge current (I ch ), maximum charge / discharge current based on the noise characteristics of engine 1 (I n )

[0048] In step S44, the battery controller 10 calculates the charge / discharge current (I ch ), the charge / discharge current (I batt ), and the charge / discharge current (I n ) among the minimum charge / discharge current (I min1 =Min(I ch , I bat , I n Then, the battery controller 10 selects the time from the current time to the scheduled start time of travel (T d1 =t s1 -t c ) and calculate the time average current (I ave1 =∫|I min1 |dt / T d1) is predicted as the charge / discharge current for raising the temperature of the battery 3. By calculating the time-average current using the absolute value of the charge / discharge current, the time-average current is affected by the current with the larger current value, either the charge current or the discharge current.

[0049] Here, the charge / discharge current based on the input / output characteristics of the external power supply equipment 17 refers to the larger of the charge current expected to flow to the battery 3 when a charger / discharger of the external power supply equipment 17 outputs a rated output current and the discharge current expected to flow to the battery 3 when a maximum input current is input to the charger / discharger of the external power supply equipment 17. The charge / discharge current based on the chargeable / dischargeable power of the battery 3 refers to the larger of the charge current expected to flow to the battery 3 when the maximum chargeable power is input to the battery 3 and the discharge current expected to flow to the battery 3 when the battery 3 outputs the maximum dischargeable power. The charge / discharge current based on the noise characteristics of the engine 1 refers to the charge current expected to flow to the battery 3 when power is supplied from the generator 2 to the battery 3 by operation of the engine 1 whose noise requirements satisfy specific requirements. The specific requirements are, for example, requirements for satisfying engine quietness, and are preset requirements.

[0050] As described above, in this embodiment, in step S44, the battery controller 10 predicts the charge / discharge current when performing temperature increase control on the battery 3 during charging, so as to satisfy all of the constraints of the electric vehicle 100 (including constraints due to the allowable input / output of the battery 3) and the constraints of the environment in which the electric vehicle 100 is placed (including constraints due to the allowable input / output of the external power supply equipment 17 and constraints due to noise from the engine 1).

[0051] In step S45, the battery controller 10 calculates the temperature rise (ΔT1) calculated in step S42, the heat capacity (C) of the battery 3 acquired in step S3, the internal resistance (R) calculated in step S43, and the charge / discharge current (I ave1 ), the temperature rise time (J1=C×ΔT1 / I) until the temperature of the battery 3 reaches the target temperature set in step S41 is calculated. ave12 When the process of step S45 is completed, the subroutine shown in FIG. 3(A) is exited and the process proceeds to step S7 shown in FIG. 2(A).

[0052] In step S7, the battery controller 10 compares the time from the current time to the scheduled start time of driving with the temperature rise time calculated in step S6, and determines whether the time until the scheduled start time of driving is longer than the temperature rise time. If the battery controller 10 makes a positive determination, the process proceeds to step S8, and if the battery controller 10 makes a negative determination, the process proceeds to step S11. Note that if the battery controller 10 makes a positive determination in this step, the battery controller 10 may calculate the scheduled start time of the temperature rise control and execute a standby process to wait until the calculated scheduled start time without proceeding to step S8. For example, the battery controller 10 calculates the time that is the temperature rise time before the scheduled start time of driving as the scheduled start time of the temperature rise control.

[0053] In step S8, the battery controller 10 executes temperature increase control on the battery 3. Specifically, the battery controller 10 repeatedly executes charge control and discharge control so that the charge / discharge current predicted in step S44 of FIG. 3A flows through the internal resistance of the battery 3. In this embodiment, the period during which the charge control and the discharge control are executed is the same. Furthermore, there is no particular limitation on the cycle during which the charge control and the discharge control are repeated.

[0054] In step S9, the battery controller 10 compares the temperature of the battery 3 detected by the temperature sensor with the target temperature (T t1 ) and determines whether the temperature of the battery 3 has reached the target temperature. If the battery controller 10 makes a positive determination, the process proceeds to step S10, and if the battery controller 10 makes a negative determination, the process returns to step S8, and the battery controller 10 executes the temperature increase control of the battery 3 until a positive determination is made in step S9.

[0055] In step S10, the battery controller 10 stops the charge / discharge control of the battery 3 executed in step S8 and ends the temperature increase control of the battery. When the process in step S10 ends, the temperature control of the battery 3 shown in FIG. 2(A) ends.

[0056] On the other hand, if a negative determination is made in step S4 or if a negative determination is made in step S7, the process proceeds to step S11. In step S11, the battery controller 10 does not execute the temperature rise control of the battery 3, and continues charging of the battery 3 by the external power supply equipment 17. If a negative determination is made in step S4, the temperature of the battery 3 is within the desired temperature range for normal driving, and therefore the temperature rise control of the battery 3 is unnecessary. If a negative determination is made in step S7, the temperature rise control of the battery 3 is unnecessary, and therefore the temperature rise control of the battery 3 cannot be raised to the desired temperature range for normal driving by the scheduled driving start time, even if the temperature rise control of the battery 3 is executed. When the processing in step S11 ends, the temperature control of the battery 3 shown in FIG. 2(A) ends.

[0057] Next, the temperature control of the battery 3 when the electric vehicle 100 is running will be described with reference to Fig. 2(B). If a negative determination is made in step S2 in Fig. 2(A), the process proceeds to step S21 shown in Fig. 2(B).

[0058] In step S21, the battery controller 10 acquires battery information about the battery 3. In step S22, the battery controller 10 acquires the current temperature (T c ) with the desired temperature range for normal operation, and determines whether the current temperature of the battery 3 is lower than the desired temperature range for normal operation. Step S21 corresponds to step S3 shown in FIG. 2(A), and step S22 corresponds to step S4 shown in FIG. 2(A), so the above-mentioned explanations are used for these steps. If the battery controller 10 makes a positive determination in step S22, the process proceeds to step S23, and if the battery controller 10 makes a negative determination, the process proceeds to step S32.

[0059] In step S23, the battery controller 10 determines whether or not high-load operation is required for the electric vehicle 100. For example, the battery controller 10 acquires travel route information from the vehicle controller 14 and determines whether or not the electric vehicle 100 will travel through a high-load operation start point within a predetermined period from the current time. If the travel route includes the high-load operation start point, the battery controller 10 determines that high-load operation is required for the electric vehicle 100, and if the travel route does not include the high-load operation start point, the battery controller 10 determines that high-load operation is not required for the electric vehicle 100. If the battery controller 10 makes a positive determination, the process proceeds to step S24, and if the battery controller 10 makes a negative determination, the process proceeds to step S30. It is assumed that in steps S21 to S23, the electric vehicle 100 is traveling through a point where the driving force of the motor 4 is lower than the reference driving force and where it can travel under normal driving.

[0060] In step S24, the battery controller 10 receives the scheduled start time (t s2 ) information is acquired. The scheduled start time of high-load operation is, for example, the scheduled time when the electric vehicle 100 passes the high-load operation start point. When the processing of step S24 ends, the process proceeds to step S25. When the process proceeds to step S25, the process proceeds to step S51 in the subroutine shown in FIG. 3(B), where the time required to heat the battery 3 up to the desired temperature range during high-load operation (heat-up time) is calculated.

[0061] In step S51, the battery controller 10 changes the desired temperature range from the desired temperature range for normal operation to the desired temperature range for high-load operation before the scheduled start time of high-load operation. The desired temperature range for high-load operation is a temperature range higher than the desired temperature range for normal operation. For example, the lower limit temperature is set to the highest temperature within the temperature range in which deterioration of the battery 3 can be suppressed, and the upper limit temperature is set to the highest temperature within the temperature range in which deterioration of the battery 3 can be tolerated up to a predetermined level. That is, in this step, the battery controller 10 sets a temperature range higher than the desired temperature range for normal operation as the desired temperature range for high-load operation. Note that the predetermined level at which deterioration of the battery 3 is tolerated is an experimentally determined value and is set in advance.

[0062] In step S52, the battery controller 10 sets the target temperature (T t2 ) is set. The target temperature of the battery 3 in this step is not particularly limited as long as it is within a desired temperature range during high-load operation. For example, the battery controller 10 sets the lower limit temperature of the desired temperature range during high-load operation as the target temperature of the battery 3.

[0063] In step S53, the battery controller 10 sets the target temperature (T t2 ) and the current temperature of the battery 3 (T c ) and the temperature difference between the battery 3 temperature rise temperature (ΔT2 = T t2 -T c ) is calculated.

[0064] In step S54, the battery controller 10 calculates the current temperature of the battery 3 (T c ) and the current state of charge (SOC) of the battery 3, the internal resistance (R) of the battery 3 is calculated. Step S54 corresponds to step S43 in FIG. 3A, and therefore the above description is used.

[0065] In step S55, the battery controller 10 predicts the charge / discharge current that flows through the internal resistance of the battery 3 while repeatedly executing the charge / discharge control of the battery 3 as the temperature increase control of the battery 3. Step S55 corresponds to step S44 shown in FIG. 3(A). In step S55, the charge / discharge current of the battery 3 that is determined due to the constraints of the electric vehicle 100 is calculated based on the charge / discharge current (I run ), charging / discharging current based on the maximum output of engine 1 (I eng ), the charge / discharge current (I batt ) The charge / discharge current of the battery 3, which is determined due to the constraints of the environment in which the electric vehicle 100 is placed, is the maximum charge / discharge current (I n )

[0066] In step S55, the battery controller 10 calculates the charge / discharge current (I run ), charging / discharging current based on the maximum output of engine 1 (I eng ), the charge / discharge current (I batt ), and the charge / discharge current (I n ) among the minimum charge / discharge current (I min2 =Min(I run , I eng , I bat , I n Then, the battery controller 10 selects the time from the current time to the scheduled start time of the high-load operation (T d2 =t s2 -t c ) and calculate the time average current (I ave2 =∫|I min2 |dt / T d2 ) is predicted as the charge / discharge current for raising the temperature of the battery 3.

[0067] Here, the charge / discharge current based on the output power required for the electric vehicle 100 to travel is the discharge current required for the battery 3 to drive the motor 4 to travel the electric vehicle 100. The charge / discharge current based on the maximum output of the engine 1 is the charge current that is expected to flow to the battery 3 when power is supplied from the generator 2 to the battery 3 by the engine 1 at maximum output. The charge / discharge current based on the chargeable / dischargeable power of the battery 3 and the charge / discharge current based on the noise characteristics of the engine 1 are described in step S44 of FIG. 3(A) .

[0068] As described above, in this embodiment, in step S55, the battery controller 10 predicts the charge / discharge current when performing temperature increase control on the battery 3 during charging, so as to satisfy all of the constraints of the electric vehicle 100 (including constraints due to the running of the electric vehicle 100, constraints due to the maximum output of the engine 1, and constraints due to the allowable input / output of the battery 3) and the constraints of the environment in which the electric vehicle 100 is placed (including constraints due to noise from the engine 1).

[0069] In step S56, the battery controller 10 calculates the temperature rise (ΔT2) calculated in step S53, the heat capacity (C) of the battery 3 acquired in step S21, the internal resistance (R) calculated in step S54, and the charge / discharge current (I ave2 ), the temperature of the battery 3 reaches the target temperature (T t2 ) to reach the temperature rise time (J2 = C × ΔT2 / I ave2 2 When the process of step S56 is completed, the subroutine shown in FIG. 3(B) is exited and the process proceeds to step S26 shown in FIG. 2(B).

[0070] In step S26, the battery controller 10 compares the time from the current time to the scheduled start time of high-load operation with the temperature rise time calculated in step S25, and determines whether the time until the scheduled start time of high-load operation is longer than the temperature rise time. If the battery controller 10 makes a positive determination, the process proceeds to step S27, and if the battery controller 10 makes a negative determination, the process proceeds to step S32. Note that in this step, if the battery controller 10 makes a positive determination, the battery controller 10 may calculate the scheduled start time of temperature rise control and execute a standby process to wait until the calculated scheduled start time without proceeding to step S27. For example, the battery controller 10 calculates the time before the scheduled start time of high-load operation by the temperature rise time as the scheduled start time of temperature rise control.

[0071] In step S27, the battery controller 10 executes temperature increase control on the battery 3. Specifically, the battery controller 10 repeatedly executes charge control and discharge control so that the charge / discharge current predicted in step S55 of Fig. 3B flows through the internal resistance of the battery 3. Note that the explanation in step S8 is used to refer to the period during which the charge control and the discharge control are executed and the cycle in which the charge control and the discharge control are repeated.

[0072] In step S28, the battery controller 10 compares the current temperature of the battery 3 detected by the temperature sensor with the target temperature (T t2 ) and determines whether the temperature of the battery 3 has reached the target temperature. If the battery controller 10 makes a positive determination, the process proceeds to step S29, and if the battery controller 10 makes a negative determination, the process returns to step S27, and the battery controller 10 executes the temperature increase control of the battery 3 until a positive determination is made in step S28.

[0073] In step S29, the battery controller 10 stops the charge / discharge control of the battery 3 executed in step S27 and ends the temperature increase control of the battery. When the process in step S29 ends, the temperature control of the battery 3 shown in FIG. 2(B) ends.

[0074] On the other hand, if a negative determination is made in step S23, the process proceeds to step S30. In step S30, the battery controller 10 stops the operation of the battery cooling system. Although high-load operation is not necessary, the temperature of the battery 3 is lower than the desired temperature range in normal operation, so the operation of the battery cooling system is stopped to increase the temperature of the battery 3 by charging and discharging the battery to run the electric vehicle 100.

[0075] In step S31, the battery controller 10 compares the current temperature of the battery 3 detected by the temperature sensor with the desired temperature range for normal operation, and determines whether the temperature of the battery 3 is lower than the desired temperature range for normal operation. If the battery controller 10 makes a positive determination, the process returns to step S30, and the battery controller 10 continues to stop the operation of the cooling system until a negative determination is made in step S31.

[0076] If a negative determination is made in step S26 or if a negative determination is made in step S31, the process proceeds to step S32. In step S32, the battery controller 10 does not execute the temperature increase control of the battery 3, and continues normal operation of the electric vehicle 100. If the process proceeds from step S31 to step S32, the operation of the cooling system was stopped in step S30, so the battery controller 10 resumes the stopped operation of the cooling system. If a negative determination is made in step S26, this is based on the viewpoint that the temperature increase control of the battery 3 is unnecessary because even if the temperature increase control of the battery 3 is executed, the temperature of the battery 3 cannot be increased to the desired temperature range for high-load operation by the scheduled start time of high-load operation. On the other hand, if a negative determination is made in step S31, this is based on the viewpoint that the electric vehicle 100 does not need high-load operation and the temperature of the battery 3 is within the desired temperature range for normal operation, so the temperature increase control of the battery 3 is unnecessary. When the process in step S32 ends, the temperature control of the battery 3 shown in FIG. 2(B) ends.

[0077] Next, the temperature control method of the battery 3 shown in FIGS. 2 and 3 will be described from the perspective of the relationship between the input / output of the battery 3 and the temperature of the battery 3, using FIGS. 4 and 5. FIG. 4 is a diagram for explaining the relationship between the temperature control of the battery 3 performed before the start of driving and the temperature of the battery 3. FIG. 4(A) is a diagram showing the input / output of the battery 3 over time. In FIG. 4(A), the vertical axis represents the input and output of the battery 3, and the horizontal axis represents time. In FIG. 4(A), the amount of charge (charging power or charging current) to the battery 3 increases toward the input side of the vertical axis, and the amount of discharge (discharging power or discharging current) from the battery 3 increases toward the output side of the vertical axis. FIG. 4(B) is a diagram showing the temperature of the battery 3 over time. In FIG. 4(B), the vertical axis represents the temperature (T) of the battery 3, and the horizontal axis represents time (t). Note that the horizontal axis in both FIGS. 4(A) and 4(B) is a common time axis.

[0078] As shown in Fig. 4, at time t0, the battery 3 is charged by the external power supply equipment 17, and the temperature of the battery 3 is lower than the desired temperature range (lower limit temperature T1 to upper limit temperature T2) in normal driving. In this situation, if the battery controller 10 executes the temperature control method shown in Fig. 2(A), the temperature of the battery 3 is lower than the expected temperature range (lower limit temperature T1 to upper limit temperature T2) in normal driving. s1 At time t1, which is before the scheduled start time of travel, the battery controller 10 starts temperature increase control. s1 In this state, the battery 3 repeatedly charges and discharges. The charge / discharge current flowing through the battery 3 due to the temperature rise control is greater than the charge current flowing through the battery 3 due to the power supplied from the external power supply equipment 17. Therefore, the temperature rise rate of the battery 3 during the execution of the temperature rise control is higher than the temperature rise rate of the battery 3 during charging. As a result, from time t1 to the scheduled running start time t s1 Then, the battery 3 heats up by itself to a target temperature that is within the desired temperature range for normal driving. s1 The temperature of the battery 3 at this time reaches the desired temperature range for normal operation, and the electric vehicle 100 can start traveling in a state in which the temperature of the battery 3 is within the desired temperature range for normal operation.

[0079] FIG. 5 is a diagram illustrating the relationship between the temperature of the battery 3 and the temperature of the battery 3, which is performed before the start of high-load operation. FIG. 5(A) is a diagram illustrating the input and output of the battery 3 over time, and FIG. 5(B) is a diagram illustrating the temperature of the battery 3 over time. The vertical and horizontal axes of FIGS. 5(A) and 5(B) are the same as those of FIGS. 4(A) and 4(B), and therefore the above explanation is incorporated herein. For convenience, the vertical axis of FIG. 5(A) indicates input and output in the opposite direction to the vertical axis of FIG. 4(A). For reference, FIG. 5(A) also shows the input and output of the engine 1 with a dashed line. The relationship between the input and output of the engine 1 is represented by the vertical axis representing the input and output of the battery 3. Moving toward the output side of the vertical axis indicates that the driving force of the engine 1 increases, and the amount of power generated by the generator 2 increases.

[0080] As shown in FIG. 5, at time t0, when the electric vehicle 100 is running in normal operation, the battery 3 discharges a predetermined amount of power to drive the motor 4, and the engine 1 generates a predetermined driving force and outputs it to the generator 2. Furthermore, as the electric vehicle 100 runs, the temperature of the battery 3 rises, and so the temperature of the battery 3 is within the desired temperature range for normal operation, but is lower than the desired temperature range (lower limit temperature T2 to upper limit temperature T3) for high-load operation (before time t0, the temperature of the battery 3 is assumed to be lower than the desired temperature range for normal operation). In this situation, when the battery controller 10 executes the temperature control method shown in FIG. 2(B), the temperature of the battery 3 rises to a predetermined value at the scheduled start time t s2 At time t2, which is before the scheduled start time of high load operation, the temperature increase control by the battery controller 10 is started. s2 During this period, the battery 3 repeatedly charges and discharges. The charge / discharge current flowing through the battery 3 due to the temperature rise control is greater than the discharge current flowing through the battery 3 to run the electric vehicle 100, so the temperature rise rate of the battery 3 during the temperature rise control is higher than the temperature rise rate of the battery 3 during normal operation. As a result, from time t2 to the scheduled start time t s2Then, the temperature of the battery 3 rises to a target temperature included in the desired temperature range for high load operation. s2 The temperature of the battery 3 at time t2 reaches the desired temperature range for high-load operation, and the electric vehicle 100 can travel on mountain roads, climbing lanes on expressways, merging points on expressways, etc., with the temperature of the battery 3 in the desired temperature range for high-load operation. s2 In this case, since the battery 3 repeatedly charges and discharges, the vehicle controller 14 changes the control of the engine 1 in accordance with the temperature rise control of the battery 3 so as not to affect the running of the electric vehicle 100 during this period. For example, as shown in FIG. 5(A), while the charging control of the battery 3 is being executed, the vehicle controller 14 controls the engine 1 so as to increase the amount of power generated by the generator 2 because power is not supplied from the battery 3 to the motor 4. Furthermore, while the discharging control of the battery 3 is being executed, the vehicle controller 14 controls the engine 1 so as to decrease the amount of power generated by the generator 2 because power is supplied from the battery 3 to the motor 4. Note that the input / output characteristics of the engine 1 during the temperature rise control shown in FIG. 5(A) are one example and are not particularly limited.

[0081] As described above, the battery temperature control method according to this embodiment is a battery temperature control method in which the battery controller 10 controls the temperature of the battery 3 mounted on the electric vehicle 100. The battery controller 10 acquires battery information, including the temperature of the battery 3, acquires information about a scheduled time when the temperature of the battery 3 must be within a desired temperature range, and, if the temperature of the battery 3 is lower than the desired temperature range, repeats charge / discharge control of the battery 3 before the scheduled time to raise the temperature of the battery 3 to the desired temperature range at the scheduled time. The battery 3 generates heat internally through repeated charging and discharging. The heating efficiency of the battery 3 due to self-heating is considered to be higher than the heating efficiency when heated by a heating device such as a heater. Therefore, the battery temperature control method and temperature control device according to this embodiment can raise the temperature of the battery 3 more efficiently than when heated by a heating device, and can raise the temperature of the battery 3 to the desired temperature range by the time when the temperature of the battery 3 needs to be raised. Furthermore, there is no need to arrange a heating device such as a heater around the battery 3, which improves the efficiency of the layout design around the battery 3 and reduces costs by reducing the number of parts. Furthermore, since the battery temperature rises to the desired temperature range at the scheduled time, the input / output power of the battery 3 increases when the electric vehicle 100 is scheduled to start traveling or when high-load operation begins, thereby enabling the battery 3 to be made more efficient.

[0082] In this embodiment, the battery controller 10 executes temperature increase control before the scheduled time when the current temperature of the battery 3 is lower than the desired temperature range. The battery 3 can be increased in temperature in advance at a timing before the scheduled time.

[0083] In this embodiment, the information on the scheduled time acquired by the battery controller 10 is the scheduled start time of the electric vehicle 100 (t s1 ), and the scheduled start time of high-load operation of the electric vehicle 100 (t s2 ) As a result, when the electric vehicle 100 starts to travel or when high-load operation starts, the input / output power of the battery 3 increases, and the efficiency of the battery 3 can be improved.

[0084] In this embodiment, the battery information acquired by the battery controller 10 is the current temperature (T c ) and the heat capacity (C) of the battery 3, and the battery controller 10 calculates the temperature rise temperature (ΔT1, ΔT2) which is the temperature difference between the target temperature included in the desired temperature range and the current temperature of the battery 3, and calculates the current temperature (T c ) and the state of charge (SOC) of the battery 3, the internal resistance (R) of the battery 3 is calculated, and the charge / discharge current (I ave1 , I ave2 ) is predicted, and the temperature of battery 3 is set to the target temperature (T t1 , T t2 ), and calculates the temperature rise time (J1, J2) until the temperature of the battery 3 reaches the desired temperature range. From the calculated temperature rise time and the scheduled time, it can be determined whether the temperature of the battery 3 will reach the desired temperature range at the scheduled time. Also, the start timing of the temperature rise control can be calculated so that the temperature of the battery 3 reaches the desired temperature range at the scheduled time.

[0085] Furthermore, in this embodiment, the battery controller 10 predicts the charge / discharge current flowing through the internal resistance during execution of the temperature rise control from the time average current per predetermined time of the minimum charge / discharge current. The minimum charge / discharge current is a current smaller than a first limit value of the charge / discharge current determined due to at least one of the constraints of the electric vehicle 100 and the constraints of the environment in which the electric vehicle 100 is placed. This makes it possible to raise the temperature of the battery 3 by self-heating using the minimum available charge / discharge current given the constraints of the electric vehicle 100 and the constraints of the environment in which the electric vehicle 100 is placed. As a result, it is possible to reduce the impact of the temperature rise control on other controls of the electric vehicle 100.

[0086] In this embodiment, the battery controller 10 predicts the charge / discharge current flowing through the internal resistance during the execution of the temperature increase control from the time average current per predetermined time of the minimum charge / discharge current. The minimum charge / discharge current is a current smaller than the second limit value of the charge / discharge current determined due to the constraints of the electric vehicle 100. The second limit value of the charge / discharge current of the battery 3 determined due to the constraints of the electric vehicle 100 is the charge / discharge current (I batt : corresponds to the "first charge / discharge current" of the present invention), a charge / discharge current (I run : corresponds to the "second charge / discharge current" of the present invention), and the charge / discharge current of the battery 3 based on the maximum output of the engine 1 (I eng The charging / discharging current is predicted as a time average current per predetermined time of the minimum charging / discharging current, and the minimum charging / discharging current is a current smaller than the second limit value of the charging / discharging current determined due to the constraints of the electric vehicle. This makes it possible to use the minimum available charging / discharging current to raise the temperature of the battery 3 by self-heating, given the constraints of the electric vehicle 100.

[0087] In this embodiment, the third limit value of the charge / discharge current of the battery 3, which is determined due to the environment in which the electric vehicle 100 is placed, is set based on the charge / discharge current (I ch : corresponds to the "fourth charge / discharge current" of the present invention), the charge / discharge current of the battery 3 based on the noise characteristics of the engine 1 (I n (This corresponds to the "fifth charge / discharge current" of the present invention.) As a result, the temperature of battery 3 can be increased by self-heating using the minimum available charge / discharge current, given the constraints of the environment in which electric vehicle 100 is placed.

[0088] Furthermore, in this embodiment, the desired temperature range is either the temperature range for normal operation or the desired temperature range for high-load operation. If the scheduled time when the temperature of battery 3 needs to be within the desired temperature range is the scheduled start time of high-load operation, the desired temperature range is changed from the temperature range for normal operation to the temperature range for high-load operation before the scheduled start time of high-load operation. This allows the temperature of battery 3 at the scheduled start time of high-load operation to be higher than the temperature range for normal operation, thereby meeting the required input / output power of battery 3 during high-load operation. Furthermore, because the possible output power of battery 3 can be increased, high-load operation by electric vehicle 100 can be achieved without, for example, adding a battery for high-load operation.

[0089] In this embodiment, the battery 3 includes a battery including a negative electrode active material whose electrode potential relative to the equilibrium potential in the reaction between lithium metal and lithium ions is 0.5 V or higher, or a battery including a power generating element in which a negative electrode active material layer that deposits lithium metal during charging, an electrolyte layer, and a positive electrode active material layer are laminated in this order. This makes it possible to alleviate the limitation on the charging current of the battery 3 in a low-temperature environment, and to repeatedly execute charge / discharge control of the battery 3 in a low-temperature environment.

[0090] In this embodiment, the battery 3 includes a battery in which an electrode mixture layer and an electrolyte layer are stacked, and at least one of the electrode mixture layer and the electrolyte layer is made of a solid electrolyte material. As a result, even if the battery 3 is, for example, a lithium secondary ion battery with an electrolyte layer using an organic electrolyte solution, it is possible to suppress the reaction between the electrode active material and the organic electrolyte solution in a high-temperature environment and improve the durability of the battery 3 in a high-temperature environment.

[0091] The above-described embodiments and modifications are provided to facilitate understanding of the present invention, and are not intended to limit the present invention. Therefore, the elements disclosed in the above embodiments are intended to include all design modifications and equivalents that fall within the technical scope of the present invention.

[0092] For example, in the above embodiment, the scheduled start time of traveling and the scheduled start time of high-load operation of the electric vehicle 100 are predicted by the vehicle controller 14. However, these scheduled times may be predicted by the battery controller 10. Although a detailed description will be omitted, the battery controller 10 can predict the scheduled times by acquiring each piece of information required for predicting the scheduled times from the vehicle controller 14.

[0093] Furthermore, for example, in the above-described embodiment, the scheduled start time of traveling and the scheduled start time of high-load operation of the electric vehicle 100 have been described as examples of scheduled times when the temperature of the battery 3 needs to be within the desired temperature range. However, the scheduled times when the temperature of the battery 3 needs to be within the desired temperature range are not limited to these scheduled times. The vehicle controller 14 may predict the scheduled time when charging of the battery 3 by the external power supply facility 17 will start (hereinafter referred to as the scheduled external charging start time) as the scheduled time when the temperature of the battery 3 needs to be within the desired temperature range. For example, the vehicle controller 14 predicts the scheduled external charging start time of the electric vehicle 100 based on travel route information and the state of charge of the battery 3 input from the navigation system 16. The vehicle controller 14 may predict the scheduled external charging start time of the electric vehicle 100 as the next charging time for the electric vehicle 100 based on installation information of the external power supply facility 17 and the state of charge of the battery 3, which are included in the travel route information. This increases the available power that can be input / output to / from the battery 3 when charging of the battery 3 by the external power supply facility 17 starts, thereby shortening the time until the battery 3 is fully charged. As described above, the scheduled external charging start time may be a scheduled time predicted by the battery controller 10, rather than by the vehicle controller 14. The scheduled times at which the temperature of the battery 3 needs to be within the desired temperature range may include at least one of the scheduled driving start time, the scheduled high-load operation start time, and the scheduled external charging start time.

[0094] Furthermore, for example, in the above-described embodiment, the battery controller 10 has been described as executing the temperature increase control of the battery 3 when the current battery temperature is lower than the desired temperature range, but the conditions for determining whether to execute the temperature increase control are not limited to this. For example, the battery controller 10 may predict the temperature of the battery 3 at the scheduled time described above based on the state of charge of the battery 3, and execute the temperature increase control of the battery 3 when the temperature of the battery 3 at the scheduled time is lower than the desired temperature range for normal operation (or the desired temperature range for high-load operation).

[0095] Furthermore, for example, in the above-described embodiment, the battery controller 10 has been described as being configured to calculate, as the minimum charge / discharge current of the battery 3, a charge / discharge current of the battery 3 that is smaller than the charge / discharge current of the battery 3 determined due to constraints on the electric vehicle 100 and the charge / discharge current of the battery 3 determined due to constraints on the environment in which the electric vehicle 100 is placed. However, the present invention is not limited to this. The battery controller 10 may calculate, as the minimum charge / discharge current of the battery 3, a charge / discharge current of the battery 3 that is smaller than at least one of the charge / discharge current of the battery 3 determined due to constraints on the electric vehicle 100 and the charge / discharge current of the battery 3 that is smaller than the charge / discharge current of the battery 3 determined due to constraints on the environment in which the electric vehicle 100 is placed.

[0096] Furthermore, for example, in the above-described embodiment, the charge / discharge current of battery 3 determined due to constraints on electric vehicle 100 may include at least one of the charge / discharge current of battery 3 based on the chargeable / dischargeable power of battery 3, the charge / discharge current of battery 3 based on the output power of battery 3 required for running electric vehicle 100, and the charge / discharge current of battery 3 based on the maximum output of engine 1. Furthermore, for example, in the above-described embodiment, the charge / discharge current of battery 3 determined due to constraints on the environment in which electric vehicle 100 is placed may include at least one of the charge / discharge current of battery 3 based on the input / output characteristics of external power supply equipment 17 and the charge / discharge current of battery 3 based on the noise characteristics of engine 1.

[0097] Furthermore, for example, in the above-described embodiment, a so-called series hybrid vehicle has been described as an example of electric vehicle 100, but the battery temperature control method and battery temperature control device according to the present invention can also be applied to so-called series-parallel vehicles and electric vehicles that are not equipped with an engine 1 for generating electricity and that drive motor 4 only with battery 3. When applied to an electric vehicle, since the only drive source for motor 4 is battery 3, it is difficult to repeat charge and discharge control as temperature rise control while the electric vehicle is traveling. For electric vehicles, temperature rise control can be executed before the scheduled start time of traveling or before the scheduled start time of external charging, so that the temperature of battery 3 at the scheduled time can be raised to a desired temperature range for normal operation. [Explanation of symbols]

[0098] 100...Electric vehicles 1. Engine 2...Generator 3. Battery 4...Motor 5...Generator inverter 6...Motor inverter 7...Power delivery module 8...Battery junction box 9...Charging plug 10...Battery controller

Claims

1. A battery temperature control method in which a controller controls the temperature of a chargeable / dischargeable battery mounted on an electric vehicle, obtaining battery information including a temperature of the battery; predicting a scheduled time when the temperature of the battery needs to be within a desired temperature range or obtaining information about the scheduled time; If the temperature of the battery is lower than the desired temperature range, charge / discharge control of the battery is repeated as temperature increase control of the battery before the scheduled time, thereby increasing the temperature of the battery to the desired temperature range at the scheduled time; the battery information includes a current temperature of the battery and a thermal capacity of the battery; calculating a temperature rise temperature that is a temperature difference between a target temperature included in the desired temperature range and a current temperature of the battery; Calculating an internal resistance of the battery based on a current temperature of the battery and a current state of charge of the battery; predicting a charge / discharge current flowing through the internal resistance during execution of the temperature rise control; A battery temperature control method for calculating a temperature rise time required for the temperature of the battery to reach the target temperature based on the temperature rise, the heat capacity, the internal resistance, and the charge / discharge current.

2. 2. The battery temperature control method according to claim 1, The battery temperature control method executes the temperature increase control when the current temperature of the battery is lower than the desired temperature range or when the temperature of the battery at the scheduled time is lower than the desired temperature range.

3. 3. The battery temperature control method according to claim 1, further comprising: The battery temperature control method, wherein the scheduled time includes at least one of a scheduled time when the electric vehicle starts traveling, a scheduled time when charging of the battery starts by an external power supply facility provided outside the electric vehicle, and a scheduled time when the output power of the battery needs to be equal to or greater than a predetermined power.

4. 2. The battery temperature control method according to claim 1, The charge / discharge current is predicted as a time average current of a minimum charge / discharge current per predetermined time period; The battery temperature control method, wherein the minimum charge / discharge current is a current smaller than a first limit value of charge / discharge current determined due to at least one of constraints of the electric vehicle and constraints of an environment in which the electric vehicle is placed.

5. 2. The battery temperature control method according to claim 1, The charge / discharge current is predicted as a time average current of a minimum charge / discharge current per predetermined time period; the minimum charge / discharge current is a current that is smaller than a second limit value of the charge / discharge current that is determined due to a constraint of the electric vehicle, a second limit value of the charge / discharge current determined due to constraints of the electric vehicle, the second limit value of the charge / discharge current being determined based on the chargeable / dischargeable power of the battery, a second limit value of the charge / discharge current being based on the output power of the battery required for running the electric vehicle, and a third limit value of the charge / discharge current being based on the maximum output of an internal combustion engine mounted in the electric vehicle for charging the battery.

6. 6. A battery temperature control method according to claim 4 or 5, a third limit value of the charge / discharge current determined due to constraints of an environment in which the electric vehicle is placed, the third limit value including at least one of a fourth charge / discharge current based on input / output characteristics of an external power supply facility provided outside the electric vehicle, and a fifth charge / discharge current based on noise characteristics of an internal combustion engine mounted in the electric vehicle for charging the battery.

7. 3. The battery temperature control method according to claim 1, further comprising: If the scheduled time is a scheduled time at which the output power of the battery needs to be equal to or greater than a predetermined power, changing the desired temperature range from a first temperature range to a second temperature range before the scheduled time; the first temperature range is a temperature range in which deterioration of the battery can be suppressed, The second temperature range is a temperature range higher than the first temperature range and allows the battery to deteriorate up to a predetermined level.

8. 3. The battery temperature control method according to claim 1, further comprising: The battery includes a negative electrode active material having an electrode potential of 0.5 V or more relative to the equilibrium potential in a reaction between lithium metal and lithium ions, or a battery including a power generating element in which a negative electrode active material layer that deposits lithium metal during charging, an electrolyte layer, and a positive electrode active material layer are stacked in this order.

9. 3. The battery temperature control method according to claim 1, further comprising: The battery includes a battery in which an electrode mixture layer and an electrolyte layer are stacked, At least one of the electrode mixture layer and the electrolyte layer is made of a solid electrolyte material.

10. A battery temperature control device including a controller and performing temperature control of a chargeable / dischargeable battery mounted on an electric vehicle, The controller obtaining battery information including a temperature of the battery; predicting a scheduled time when the temperature of the battery needs to be within a desired temperature range or obtaining information about the scheduled time; If the temperature of the battery is lower than the desired temperature range, charge / discharge control of the battery is repeated as temperature increase control of the battery before the scheduled time, thereby increasing the temperature of the battery to the desired range at the scheduled time; the battery information includes a current temperature of the battery and a thermal capacity of the battery; The controller calculating a temperature rise temperature that is a temperature difference between a target temperature included in the desired temperature range and a current temperature of the battery; Calculating an internal resistance of the battery based on a current temperature of the battery and a current state of charge of the battery; predicting a charge / discharge current flowing through the internal resistance during execution of the temperature rise control; a battery temperature control device that calculates a temperature rise time required for the temperature of the battery to reach the target temperature based on the temperature rise, the heat capacity, the internal resistance, and the charge / discharge current;

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