Method for charging a vehicle and an external charger

Abstract

The present disclosure relates to a vehicle and a method of external charging. A vehicle (1) charges a battery (10) using supply electric power supplied from an external power supply, the vehicle (1) including: the battery (10); a temperature sensor (17) that detects a temperature of the battery (10); a temperature raising device for raising the temperature of the battery (10); and a control device. In execution of external charging, the control device executes, during a period in which the temperature of the battery (10) is less than a reference temperature, a state of charge control that drives the temperature raising device while maintaining the state of charge of the battery (10) within a predetermined range to raise the temperature of the battery (10), and in the state of charge control, the control device causes the temperature raising device to intermittently operate while the battery (10) continuously receives the supply electric power, in a case where the supply electric power is less than a minimum value that can be obtained by the consumption electric power of the temperature raising device.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a vehicle configured to be capable of external charging, which is charging of a battery mounted on the vehicle by accepting supply of electric power from outside the vehicle, and a method of external charging. BACKGROUND

[0002] In the battery system disclosed in Japanese Patent Application Publication No. 2017-99057, in a case where the electric power supplied from the external power supply to the vehicle is less than a reference electric power, the drive of the warming-up mechanism in a state where the SOC (State Of Charge) of the main battery is less than a charging reference value is prohibited. The battery system first charges the SOC of the main battery to be equal to or higher than the charging reference value, and then performs the warming-up processing (see Japanese Patent Application Publication No. 2017-99057). SUMMARY

[0003] In the external charging, in a case where the temperature of the battery is lower than a reference temperature, the warming-up device is sometimes operated to warm up the temperature of the battery to be equal to or higher than the reference temperature. In this case, the supply electric power supplied from the external power supply is divided into a charging electric power for charging the battery and an electric power for driving the warming-up device (consumption electric power of the warming-up device).

[0004] In a case where the supply electric power is large enough, both the charging of the battery and the drive of the warming-up device can be performed simultaneously, but there can be a case where the supply electric power is small to such an extent that both the charging of the battery and the drive of the warming-up device cannot be performed simultaneously. In such a case, in order to charge the battery, the warming-up device must be stopped. The battery system disclosed in Japanese Patent Application Publication No. 2017-99057 adopts a structure in which the warming-up processing is performed after the charging is performed in a case where the electric power is less than the reference electric power, but if the time required for the external charging (the time required for the charging of the battery and the time required for the warming-up) is taken into account, there is room for further improvement.

[0005] The present disclosure can solve the above-described problem, and in a case where the temperature of the battery is lower than a reference temperature at the time of external charging, the increase in the time required for the external charging can be suppressed.

[0006] (1) The vehicle of the first aspect of the present application is a vehicle configured to be capable of performing external charging in which a battery mounted on the vehicle is charged with supplied electric power supplied from an electric power source outside the vehicle. The vehicle includes the battery, a temperature sensor that detects a temperature of the battery, a temperature raising device that raises the temperature of the battery, and a control device that controls the external charging and the temperature raising device. During execution of the external charging, the control device executes charge amount control in which the temperature raising device is driven to raise the temperature of the battery while maintaining a charge amount of the battery within a predetermined range, during a period in which the temperature of the battery is less than a reference temperature. In the charge amount control, in a case where the supplied electric power is less than a minimum value at which the consumed electric power can be obtained, the control device maintains the charge amount of the battery within the predetermined range while causing the temperature raising device to intermittently operate while the battery continuously receives the supplied electric power.

[0007] According to the above structure, the vehicle continuously receives the supplied electric power. The received supplied electric power is used, for example, for driving of the temperature raising device, and a deficient portion thereof is taken out from the battery. Thus, as compared with a case where the supplied electric power is not received, it is possible to reduce the electric power taken out from the battery for driving of the temperature raising device. Therefore, it is possible to slow down a decrease in the charge amount of the battery. Alternatively, the received supplied electric power is charged to the battery, for example, and the electric power for driving of the temperature raising device is taken out from the battery. Thus, as compared with a case where the supplied electric power is not received, it is possible to slow down a decrease in the charge amount of the battery. Since it is possible to slow down a decrease in the charge amount of the battery, it is possible to extend a driving time of the temperature raising device. As a result, it is possible to quickly raise the temperature of the battery to the reference temperature. Thus, it is possible to suppress an increase in time required for the external charging.

[0008] (2) In the vehicle of the above aspect, the control device can stop the temperature raising device and charge the battery with the supplied electric power when the charge amount of the battery decreases to a lower limit value of the predetermined range in the charge amount control.

[0009] According to the above structure, it is possible to appropriately maintain the charge amount of the battery within the predetermined range.

[0010] (3) In the vehicle of the above aspect, the control device can intermittently execute charging of the battery in a manner such that the charge amount of the battery becomes the predetermined range while causing the temperature raising device to always operate, in a case where the supplied electric power is greater than a maximum value at which the consumed electric power can be obtained in the charge amount control.

[0011] According to the above structure, the temperature raising device is caused to always operate, and thus it is possible to quickly raise the temperature of the battery to the reference temperature.

[0012] (4) In the vehicle of the above technical means, the control device can also exclusively perform (i) charging of the battery using the supplied electric power and (ii) operation of the warming device using electric power of the battery without accepting the supplied electric power in such a manner that the charge of the battery becomes within the predetermined range, in the case where the supplied electric power is smaller than the maximum value of the supplied electric power obtainable in relation to the consumed electric power and is larger than the minimum value of the supplied electric power obtainable in relation to the consumed electric power in the charge control.

[0013] The case where the supplied electric power is smaller than the maximum value of the supplied electric power obtainable in relation to the consumed electric power and is larger than the minimum value of the supplied electric power obtainable in relation to the consumed electric power is, in other words, the case where the supplied electric power and the consumed electric power are of the same order. For example, in the case where the charge of the battery is calculated by the current integration method, it is possible that the input and output currents to and from the battery are mixed with detection errors of sensors, and the charge cannot be calculated with good accuracy. According to the above structure, charging of the battery and operation of the warming device are exclusively performed, and thus it is possible to ensure the calculation accuracy of the charge.

[0014] (5) In the vehicle of the above technical means, the upper limit value of the predetermined range can be set to a value at which the battery is not overcharged due to an increase in the charging electric power of the battery accompanying the stopping of the warming device in the execution of the charge control, based on the supplied electric power and the consumed electric power of the warming device.

[0015] In the case where the battery is warmed in external charging, if the temperature of the battery reaches the reference temperature halfway, the warming device is stopped. Then, the charging electric power is increased by an amount corresponding to the consumed electric power of the warming device. In the case where the charge of the battery is close to full charge, there is a possibility that the battery is overcharged due to the increase in the charging electric power. According to the above structure, the upper limit value of the predetermined range is set to a value at which the battery is not overcharged due to an increase in the charging electric power of the battery accompanying the stopping of the warming device in the execution of the charge control. Furthermore, by keeping the charge of the battery within the predetermined range, even if the charging electric power is increased due to the stopping of the warming device, it is possible to suppress the battery from being overcharged.

[0016] The method of external charging of the second technical means of the present application is a method of external charging of a battery mounted in a vehicle using supplied electric power supplied from an electric power source outside the vehicle, the battery being capable of being warmed by a warming device. The method of external charging includes, in the execution of the external charging, during a period in which the temperature of the battery is less than a reference temperature, performing charge control in which the battery is warmed while the charge of the battery is kept within a predetermined range by driving the warming device, and in the charge control, in the case where the supplied electric power is smaller than the minimum value of the supplied electric power obtainable in relation to the consumed electric power of the warming device, keeping the charge of the battery within the predetermined range while the warming device is intermittently operated while the battery continuously accepts the supplied electric power.

[0017] In the method of the above technical solution, the external charging and the temperature raising device can be controlled by a control device on board the vehicle.

[0018] According to the present disclosure, when the temperature of the battery is lower than the reference temperature during external charging, the increase in the time required for external charging can be suppressed. BRIEF DESCRIPTION OF DRAWINGS

[0019] Features, advantages, and technical and industrial significance of exemplary embodiments of the application will be described below with reference to the accompanying drawings, in which like numerals denote like elements, and wherein:

[0020] Figure 1 is a diagram showing the structure of the vehicle of the present embodiment.

[0021] Figure 2 is a diagram for explaining the 1st SOC constant control.

[0022] Figure 3 is a diagram for explaining the 2nd SOC constant control.

[0023] Figure 4 is a diagram for explaining the 3rd SOC constant control.

[0024] Figure 5 is a flowchart showing the steps of the process performed by the ECU during AC charging. DETAILED DESCRIPTION

[0025] Hereinafter, the embodiments of the present disclosure will be explained in detail with reference to the drawings. Note that the same or equivalent portions in the drawings are denoted by the same reference numerals, and their explanations will not be repeated.

[0026] <Overall structure diagram>

[0027] <<Vehicle>>

[0028] Figure 1 is a diagram showing the structure of the vehicle 1 of the present embodiment. The vehicle 1 of the present embodiment is an electric vehicle. Note that the vehicle 1 is not limited to an electric vehicle as long as it is capable of external charging in which the battery on board is charged using electric power supplied from a power source outside the vehicle 1. For example, the vehicle 1 can be a plug-in hybrid vehicle or a fuel cell vehicle.

[0029] Reference Figure 1The vehicle 1 is provided with a battery 10, a voltage sensor 15, a current sensor 16, a temperature sensor 17, a power control unit (hereinafter also referred to as "PCU (Power Control Unit)") 20, a motor generator 25, a power transmission gear 30, drive wheels 35, an inlet 40, a charger 50, a voltage sensor 55, a current sensor 57, a DC / DC converter 60, a heater 70, an auxiliary battery 75, and an ECU (Electronic Control Unit) 80. The vehicle 1 of the present embodiment is configured to be capable of AC charging in which the battery 10 is charged with alternating-current electric power supplied from an AC charging device 300 outside the vehicle. Note that, in the AC charging in the present embodiment, not only is the alternating-current electric power supplied from the AC charging device 300 used for charging of the battery 10, but also the alternating-current electric power supplied from the AC charging device 300 is sometimes used for driving of on-vehicle devices. That is, in the present embodiment, performing AC charging means accepting supply of alternating-current electric power from the AC charging device 300.

[0030] The battery 10 is mounted on the vehicle 1 as a driving power source (i.e., a power source). The battery 10 is configured to include a plurality of batteries stacked. The battery is, for example, a secondary battery such as a nickel-hydrogen battery, a lithium-ion battery, or the like. In addition, the battery can be either a battery having a liquid electrolyte between a positive electrode and a negative electrode or a battery having a solid electrolyte (an all-solid-state battery).

[0031] The voltage sensor 15, the current sensor 16, and the temperature sensor 17 function as monitoring units of the battery 10. The voltage sensor 15 detects the voltage VB of the battery 10 and outputs a signal indicating the detection result to the ECU 80. The current sensor 16 detects the input / output current (battery current) IB of the battery 10 and outputs a signal indicating the detection result to the ECU 80. The temperature sensor 17 detects the temperature (battery temperature) TB of the battery 10 and outputs a signal indicating the detection result to the ECU 80.

[0032] The PCU 20 is electrically connected to the battery 10 through power lines PL1, NL1. The PCU 20 converts direct-current electric power accumulated in the battery 10 into alternating-current electric power and supplies the alternating-current electric power to the motor generator 25 in accordance with a control signal from the ECU 80. In addition, the PCU 20 converts alternating-current electric power generated by the motor generator 25 into direct-current electric power and supplies the direct-current electric power to the battery 10. The PCU 20 is configured to include, for example, an inverter and a converter that steps up a direct-current voltage supplied to the inverter to be higher than the output voltage of the battery 10.

[0033] The motor generator 25 is an alternating-current rotary electric machine, for example, a permanent magnet type synchronous motor having a rotor in which permanent magnets are embedded. The rotor of the motor generator 25 is mechanically connected to the drive wheel 35 via the power transmission gear 30. The motor generator 25 generates kinetic energy for running the vehicle 1 by receiving alternating-current electric power from the PCU 20. The kinetic energy generated by the motor generator 25 is transmitted to the power transmission gear 30. On the other hand, when the vehicle 1 is decelerated or stopped, the motor generator 25 converts the kinetic energy of the vehicle 1 into electric energy. The alternating-current electric power generated by the motor generator 25 is converted into direct-current electric power by the PCU 20 and supplied to the battery 10. Thus, regenerative electric power can be stored in the battery 10. In this way, the motor generator 25 is configured to generate driving force or braking force of the vehicle 1 in association with exchange of electric power between the battery 10 (i.e., charging and discharging of the battery 10).

[0034] The inlet 40 is configured to be able to connect the connector 340 of the AC charging device 300. The inlet 40 is electrically connected to the charger 50 via the power lines CPL, CNL. In addition, the signal lines L1, L2 are provided between the inlet 40 and the ECU 80. The signal line L1 is a signal line for transmitting a pilot signal (CPLT signal) for exchanging predetermined information between the vehicle 1 and the AC charging device 300. Note that details of the CPLT signal will be described later. The signal line L2 is a signal line for transmitting a connector connection signal PISW indicating the connection state of the inlet 40 and the connector 340. The signal level of the connector connection signal PISW changes depending on the connection state of the inlet 40 and the connector 340. That is, the connector connection signal PISW has different potentials in the case where the inlet 40 and the connector 340 are connected and in the case where the inlet 40 and the connector 340 are not connected. The ECU 80 is able to detect the connection state of the inlet 40 and the connector 340 by detecting the potential of the connector connection signal PISW.

[0035] The charger 50 is electrically connected between the battery 10 and the inlet 40. The charger 50 includes, for example, an AC / DC conversion section, a DC / AC conversion section, and an isolation transformer, and the like. The charger 50 converts electric power received from the AC charging device 300 via the inlet 40 into electric power for charging the battery 10 based on a control signal from the ECU 80, and supplies the electric power to the battery 10. In addition, the charger 50 can be configured to be able to perform bidirectional electric power conversion. In this case, the charger 50 converts electric power received from the battery 10 into alternating-current electric power based on a control signal from the ECU 80, and supplies the electric power to the AC charging device 300.

[0036] The voltage sensor 55 is provided between the power lines CPL, CNL that electrically connect the inlet 40 and the charger 50. The voltage sensor 55 detects the voltage VIN between the power lines CPL, CNL and outputs a signal indicative of the detection result to the ECU 80.

[0037] The current sensor 57 detects the current IIN flowing in the power lines CPL, CNL and outputs a signal indicative of the detection result to the ECU 80.

[0038] The DC / DC converter 60 is electrically connected between the power lines PL2, NL2 and the low-voltage line EL. The DC / DC converter 60 steps down the voltage between the power lines PL2, NL2 and supplies to the low-voltage line EL. The DC / DC converter 60 operates in accordance with a control signal from the ECU 80.

[0039] Various auxiliary devices are electrically connected to the low-voltage line EL. In the present embodiment, the heater 70 is exemplified as the auxiliary device. In addition, an auxiliary battery 75 is electrically connected to the low-voltage line EL. Note that the ECU 80 is also electrically connected to the low-voltage line EL. Figure 1

[0040] The heater 70 is configured to be capable of warming up the battery 10. The heater 70 is configured to include a resistor that generates Joule heat by using the electric power supplied from the DC / DC converter 60 to heat the battery 10. The amount of heat generation (amount of energization) of the heater 70 is controlled by the ECU 80. In the present embodiment, the amount of heat generation of the heater 70 is controlled by the ECU 80 to be constant (e.g., the maximum amount of heat generation) in the execution of the AC charging. Note that the heater 70 corresponds to an example of the "warming-up device" of the present disclosure.

[0041] The ECU 80 includes a CPU (Central Processing Unit) 81, a memory 82, and an input / output port (not shown). The memory 82 includes a ROM (Read Only Memory) and a RAM (Random Access Memory) that stores programs and the like executed by the CPU 81. The CPU 81 expands the program stored in the ROM in the RAM and executes it. The CPU 81 performs predetermined arithmetic processing based on various signals input from the input / output port and information stored in the memory 82, and controls each device such as the PCU 20, the charger 50, and the DC / DC converter 60, and the AC charging device 300 based on the result of the arithmetic processing. Note that, as for these controls, processing by dedicated hardware (electronic circuit) can be performed in addition to or instead of processing based on software.

[0042] ​Further, the memory 82 stores specification information of the heater 70. The specification information of the heater 70 includes, for example, a control deviation value a of the heater 70 and information of the consumed electric power of the heater 70. The control deviation value a is caused by, for example, a design error of the heater 70 or the like.

[0043] Further, the memory 82 stores a map for deriving the output power limit value Wout of the battery 10. The map defines a relationship among the SOC of the battery 10, the battery temperature TB, and the output power limit value Wout. The ECU 80 can calculate the output power limit value Wout using the map with the SOC of the battery 10 and the battery temperature TB as arguments. The map can be derived, for example, from the specification of the vehicle 1, a simulation result, or an experimental result, or the like.

[0044] The ECU 80 calculates the SOC of the battery 10. The method of calculating the SOC can employ, for example, a publicly known method such as the current integration method or the OCV estimation method. In the present embodiment, the ECU 80 calculates the SOC by the current integration method.

[0045] The ECU 80 controls the AC charging. The ECU 80 controls the charger 50 to charge the battery 10 in such a manner that the SOC of the battery 10 becomes a target SOC at the start of the AC charging. The target SOC is, for example, the full charge. Note that the target SOC can be, for example, an SOC set by the user of the vehicle 1. The user of the vehicle 1 can set the target SOC, for example, by an operation on a navigation device (not shown) of the vehicle 1 or an operation on the AC charging device 300. In the present embodiment, it is assumed that the target SOC is the full charge. Note that the full charge is an SOC that becomes an upper limit in the control of the battery 10.

[0046] Further, the ECU 80 executes a process of warming up the battery 10 in a case where the battery temperature TB is less than the reference temperature Tth at the time of AC charging. The ECU 80 executes SOC constant control in which the SOC is kept in a predetermined range before the warming up of the battery 10 is completed, in a case where the heater 70 is driven to warm up the battery 10 in the AC charging. The SOC constant control is executed in order to suppress overcharge of the battery 10. In a case where the battery 10 is warmed up while the AC charging is executed, the electric power supplied from the AC charging device 300 to the vehicle 1 (hereinafter also referred to as "supplied electric power Pc") is divided into the charging electric power PB for charging the battery 10 and the drive electric power (consumption electric power) Ph of the heater 70. At the time when the battery 10 is charged to be close to full charge, if the warming up of the battery 10 is completed and the heater 70 is stopped, the amount of the consumption electric power Ph of the heater 70 is changed to the charging electric power PB, and the charging electric power PB increases the amount of the consumption electric power Ph of the heater 70. At this time, the battery 10 has already been charged to be close to full charge, and thus overcharge can occur. Therefore, in a case where the battery 10 is warmed up while the AC charging is executed, overcharge of the battery 10 can be suppressed by keeping the SOC in the predetermined range.

[0047] The predetermined range is determined by an upper limit value and a lower limit value. The upper limit value of the predetermined range can be determined, for example, on the basis of the supplied electric power Pc, the consumption electric power Ph of the heater 70, and a specification related to overcharge of the battery 10. The specification related to overcharge of the battery 10 can be identified in advance at the design stage of the vehicle 1 or the like, for example, and thus the upper limit value of the predetermined range for which the battery 10 does not reach overcharge at the time when the heater 70 is stopped can be determined in accordance with the supplied electric power Pc and the consumption electric power Ph of the heater 70. The lower limit value of the predetermined range is set to a value that is smaller than the upper limit value of the predetermined range by an amount of several percent (for example, 1%) of the SOC, for example, on the basis of a specification related to the charge amount of the battery 10. Further details of the SOC constant control will be described later. Note that the SOC constant control corresponds to an example of "charge amount control" of the present disclosure.

[0048] Note that the ECU 80 can also be configured to be divided into a plurality of ECUs in terms of functions. For example, the ECU 80 can be divided into an ECU having a function of controlling charging of the battery 10 and an ECU having a function of controlling the heater 70.

[0049] <<AC charging device>>

[0050] The AC charging device 300 includes an AC power source 310, an EVSE (Electric Vehicle Supply Equipment) 320, and a charging cable 330. A connector 340 configured to be connectable to the inlet 40 of the vehicle 1 is provided at a top end of the charging cable 330.

[0051] The AC power source 310 is constituted by, for example, a commercial system power source, but is not limited thereto, and various power sources can be applied.

[0052] The EVSE 320 controls supply and cutoff of AC power from the AC power source 310 to the vehicle 1 via the charging cable 330. The EVSE 320 is provided with a CCID (Charging Circuit Interrupt Device) 321 and a CPLT control circuit 322. The CCID 321 is a relay provided in a power supply path from the AC power source 310 to the vehicle 1.

[0053] The CPLT control circuit 322 generates a CPLT signal (pilot signal) and transmits the generated CPLT signal to the ECU 80 of the vehicle 1 via a signal line included in the charging cable 330. The CPLT signal is operated by a potential. The CPLT control circuit 322 controls the CCID 321 on the basis of the potential of the CPLT signal. That is, the ECU 80 can remotely operate the CCID 321 by operating the potential of the CPLT signal. Note that, as to a method of changing the potential of the CPLT signal, a publicly known method can be used, although not described in detail herein, and, for example, a circuit structure disclosed in Japanese Patent Application Publication No. 2016-82801 or the like can be applied.

[0054] <Heating of battery during AC charging>

[0055] In the AC charging, in a case where the temperature of the battery is lower than a reference temperature, it is preferable to cause the heater 70 to operate to raise the temperature of the battery 10 to the reference temperature Tth or higher. The reference temperature Tth is determined on the basis of the electric power required for running the vehicle 1 after the AC charging. For example, a value obtained by adding a predetermined margin to the electric power required for running the vehicle 1 can be set as an output electric power limit value Wout, and a temperature derived by comparing the output electric power limit value Wout and the SOC at the completion of the AC charging with a map can be set as the reference temperature Tth. The SOC at the completion of the AC charging is, for example, full charge.

[0056] In addition, it is desirable to quickly complete the warming of the battery 10 and shorten the time required for AC charging. In a case where the electric power supplied from the AC charging device 300 to the vehicle 1 (supplied electric power Pc) is sufficiently large relative to the consumption electric power Ph of the heater 70, both the charging of the battery 10 and the driving of the heater 70 can be simultaneously performed. On the other hand, there can be a case where the supplied electric power Pc is small to such an extent that both the charging of the battery 10 and the driving of the heater 70 cannot be simultaneously performed. Moreover, in a case where the supplied electric power Pc and the consumption electric power Ph of the heater 70 are of the same extent, when both the charging of the battery 10 and the driving of the heater 70 are simultaneously performed, the battery current IB (charge / discharge current) becomes small and the detection error of the current sensor 16 is mixed in, and accurate calculation of the SOC based on the current integration method cannot be performed. Thus, in the vehicle 1 of the present embodiment, the ECU 80 does not perform the same SOC constant control, but selectively performs the 1st to 3rd SOC constant controls depending on the relationship between the supplied electric power Pc and the consumption electric power Ph of the heater 70.

[0057] Specifically, the ECU 80 compares the supplied electric power Pc with the maximum value Ph+α of the consumption electric power Ph of the heater 70 that can be obtained and the minimum value Ph-α of the consumption electric power Ph of the heater 70 that can be obtained, taking into account the control offset value a of the heater 70. The ECU 80 performs the 1st SOC constant control in a case where the supplied electric power Pc is larger than the maximum value Ph+α (Pc > Ph+α). The ECU 80 performs the 2nd SOC constant control in a case where the supplied electric power Pc is smaller than the minimum value Ph-α (Pc < Ph-α). The ECU 80 performs the 3rd SOC constant control in a case where the supplied electric power Pc is equal to or smaller than the maximum value Ph+α and equal to or larger than the minimum value Ph-α (Ph-α ≤ Pc ≤ Ph+α). Note that, in the present embodiment, as described above, the heater 70 is controlled by the ECU 80 to have a constant heating amount (consumption electric power) (for example, a maximum heating amount), but in a case where the heating amount is changed each time, it is only necessary to calculate the consumption electric power Ph of the heater 70 each time.

[0058] (1) 1st SOC constant control: Pc > Ph+α

[0059] The 1st SOC constant control is control in which the charging and the warming of the battery 10 are simultaneously performed from the start of AC charging, and after the SOC of the battery 10 reaches the upper limit value of the predetermined range, the warming is always continued until the battery temperature TB reaches the reference temperature Tth, and the charging is intermittently performed.

[0060] Figure 2 is a view for explaining the 1st SOC constant control. Figure 2 and the 2nd SOC constant control described later Figure 3 , 4the vertical axis indicates the SOC of the battery 10, and the horizontal axis indicates time. CP0 of the vertical axis indicates the SOC of the battery 10 at the start of AC charging, CP1 indicates the lower limit value of the predetermined range, CP2 indicates the upper limit value of the predetermined range, and CPmax indicates the SOC of the battery 10 at full charge.

[0061] At time tO, the ECU 80 starts AC charging, and starts the temperature increase of the battery 10 by driving the heater 70 using a part of the supplied electric power Pc while charging the battery 10 using a part of the supplied electric power Pc. Thereby, the SOC of the battery 10 increases, and the battery temperature TB also increases. Note that, in the present embodiment, the SOC of the battery 10 is controlled to be within the predetermined range by the ECU 80. Figure 2 Figure 3 4

[0062] At time t1, when the SOC of the battery 10 reaches the upper limit value CP2 of the predetermined range, the ECU 80 stops the supply of the supplied electric power Pc from the AC charging device 300, and drives the heater 70 using the electric power of the battery 10. That is, the charging of the battery 10 is stopped, but the temperature increase of the battery 10 is continued. Thereby, from time t1 to time t2, the SOC of the battery 10 decreases from the upper limit value CP2. Note that, the stop of the supply of the supplied electric power Pc in AC charging is realized, for example, by disconnecting the CCID 321. The CCID 321 is remotely operated, for example, by the operation of the potential of the CPLT signal by the ECU 80.

[0063] At time t2, when the SOC of the battery 10 decreases to the lower limit value CP1 of the predetermined range, the ECU 80 starts the supply of the supplied electric power Pc from the AC charging device 300 again, and performs the charging and temperature increase of the battery 10 by the supplied electric power Pc. Thereby, the SOC of the battery 10 increases from time t2 to time t3.

[0064] At time t3, when the SOC of the battery 10 reaches the upper limit value CP2 of the predetermined range, the ECU 80 stops the supply of the supplied electric power Pc from the AC charging device 300, and drives the heater 70 using the electric power of the battery 10. Thereby, from time t3 to time t4, the SOC of the battery 10 decreases from the upper limit value CP2.

[0065] At time t4, when the SOC of the battery 10 decreases to the lower limit value CP1 of the predetermined range, the ECU 80 starts the supply of the supplied electric power Pc from the AC charging device 300 again, and performs the charging and temperature increase of the battery 10 by the supplied electric power Pc.

[0066] ​​​Thus, the ECU 80 warms up the battery temperature TB to the reference temperature Tth or higher while maintaining the SOC of the battery 10 in the predetermined range. Note that the ECU 80 ends the first SOC constant control when the battery temperature TB becomes the reference temperature Tth or higher, and charges the battery 10 to CPmax (full charge). When the SOC of the battery 10 reaches CPmax, the ECU 80 ends the AC charging.

[0067] (2) Second SOC Constant Control: Pc < Ph - a

[0068] The second SOC constant control is control in which, first, the battery 10 is charged to the upper limit value CP2 of the predetermined range without warming up the battery 10, and after the SOC of the battery 10 reaches the upper limit value of the predetermined range, the supply of the supply power Pc from the AC charging device 300 is continued while intermittently performing warming up until the battery temperature TB reaches the reference temperature Tth. That is, in the second SOC constant control, the supply of the supply power Pc from the AC charging device 300 is always continued.

[0069] Figure 3 is a graph for explaining the second SOC constant control.

[0070] At time t10, the ECU 80 starts the AC charging, and starts charging of the battery 10 using the supply power Pc. Thus, from time t10 to time t11, the SOC of the battery 10 rises.

[0071] At time t11, when the SOC of the battery 10 reaches the upper limit value CP2 of the predetermined range, the ECU 80 stops charging of the battery 10 (PB = 0), and uses the supply power Pc for driving of the heater 70. An insufficient part of the power for driving the heater 70 is taken out from the battery 10. Thus, from time t11 to time t12, the SOC of the battery 10 decreases from the upper limit value CP2.

[0072] At time t12, when the SOC of the battery 10 decreases to the lower limit value CP1 of the predetermined range, the ECU 80 stops the heater 70 to stop warming up of the battery 10. Also, the ECU 80 uses the supply power Pc for charging of the battery 10 (PB = Pc), and performs charging of the battery 10. Thus, the SOC of the battery 10 rises from time t12 to time t13. When attention is paid to the warming up of the battery 10, the battery 10 warms up for a time (warming up time Time A) between time t11 and time t12.

[0073] Here, in the second SOC constant control, Figure 3In the middle, the SOC versus time relationship when the supply of the supply electric power Pc from the AC charging device 300 is stopped when the SOC of the battery 10 reaches the upper limit value CP2 of the predetermined range is shown by a broken line U1. When the supply of the supply electric power Pc from the AC charging device 300 is stopped, the electric power for driving the heater 70 is taken out from the battery 10, so the SOC of the battery 10 decreases rapidly to the lower limit value CP1 compared with the case where the supply of the supply electric power Pc from the AC charging device 300 is continued. Then, the heater 70 is stopped at this time. That is, the warming-up time TimeB of the battery 10 in this case is the time between the time tll and the time tx (tll < tx < tl2). The warming-up time TimeB is shorter than the warming-up time TimeA. In this way, by continuing the supply of the supply electric power Pc from the AC charging device 300, it is possible to slow down the decrease of the SOC of the battery 10. As a result, it is possible to extend the warming-up time of the battery 10, so it is possible to quickly complete the warming-up of the battery 10 (it is possible to quickly make the battery temperature TB the reference temperature Tth or more).

[0074] At the time t13, when the SOC of the battery 10 reaches the upper limit value CP2 of the predetermined range, the ECU 80 stops the charging to the battery 10 (PB = 0) and uses the supply electric power Pc for the driving of the heater 70. The insufficient part of the electric power for driving the heater 70 is taken out from the battery 10. Therefore, from the time t13 to the time tl4, the SOC of the battery 10 decreases from the upper limit value CP2.

[0075] At the time tl4, when the SOC of the battery 10 decreases to the lower limit value CP1 of the predetermined range, the ECU 80 stops the heater 70 and performs the charging of the battery 10 by the supply electric power Pc.

[0076] In this way, the ECU 80 warms up the battery temperature TB to the reference temperature Tth or more while maintaining the SOC of the battery 10 in the predetermined range. In the execution of the 2nd SOC constant control, by continuing the supply of the supply electric power Pc from the AC charging device 300, it is possible to slow down the decrease of the SOC at the time of the driving of the heater and extend the warming-up time. Note that the ECU 80 ends the 2nd SOC constant control when the battery temperature TB becomes the reference temperature Tth or more and charges the battery 10 to CPmax (full charge). When the SOC of the battery 10 reaches CPmax, the ECU 80 ends the AC charging.

[0077] Note that, in the above, an example is explained in which when the SOC of the battery 10 reaches the upper limit value CP2 of the predetermined range, the charging to the battery 10 is stopped (PB = 0), and the supply electric power Pc is used for driving of the heater 70, but it is also possible to charge the battery 10 with the supply electric power Pc while taking out the driving electric power of the heater 70 from the battery 10.

[0078] (3) 3rd SOC Constant Control: Ph - a ≤ Pc ≤ Ph + a

[0079] The 3rd SOC constant control is control in which, first, the battery 10 is charged to the upper limit value CP2 of the predetermined range without warming up the battery 10, and after the SOC of the battery 10 reaches the upper limit value of the predetermined range, the charging and the warming up of the battery 10 are exclusively performed until the battery temperature TB reaches the reference temperature Tth. That is, in the 3rd SOC constant control, the charging and the warming up of the battery 10 are alternately performed. In more detail, in the 3rd SOC constant control, the charging of the battery 10 based on the supply electric power Pc accepted from the AC charging device 300 and the warming up of the battery 10 based on the driving of the heater 70 using the electric power of the battery 10 are alternately performed.

[0080] Figure 4 is a graph for explaining the 3rd SOC constant control.

[0081] At time t20, the ECU 80 starts the AC charging, and starts the charging of the battery 10 using the supply electric power Pc. Due to this, from time t20 to time t21, the SOC of the battery 10 rises.

[0082] At time t21, when the SOC of the battery 10 reaches the upper limit value CP2 of the predetermined range, the ECU 80 stops the supply of the supply electric power Pc from the AC charging device 300, and stops the charging to the battery 10. Also, the ECU 80 drives the heater 70 using the electric power of the battery 10, and warms up the battery. Due to this, from time t21 to time t22, the SOC of the battery 10 decreases from the upper limit value CP2.

[0083] At time t22, when the SOC of the battery 10 decreases to the lower limit value CP1 of the predetermined range, the ECU 80 stops the heater 70, and stops the warming up of the battery 10. Also, the ECU 80 starts the supply of the supply electric power Pc from the AC charging device 300 again, and charges the battery 10. Due to this, the SOC of the battery 10 rises from time t22 to time t23.

[0084] At time t23, when the SOC of the battery 10 reaches the upper limit value CP2 of the predetermined range, the ECU 80 stops the supply of the supply electric power Pc from the AC charging device 300, and stops the charging of the battery 10. Also, the ECU 80 drives the heater 70 using the electric power of the battery 10, and warms up the battery. Thereby, from time t23 to time t24, the SOC of the battery 10 decreases from the upper limit value CP2.

[0085] At time t24, when the SOC of the battery 10 decreases to the lower limit value CP1 of the predetermined range, the ECU 80 stops the heater 70, and again starts the supply of the supply electric power Pc from the AC charging device 300, and performs the charging of the battery 10 using the supply electric power Pc.

[0086] Thus, the ECU 80 warms up the battery temperature TB to the reference temperature Tth or more while maintaining the SOC of the battery 10 in the predetermined range. In the case where the supply electric power Pc and the consumption electric power Ph of the heater 70 are of the same order (Ph-α ≤ Pc ≤ Ph+α), if both the charging of the battery 10 and the driving of the heater 70 are performed at the same time, the battery current IB (charge-discharge current) becomes small and the detection error of the current sensor 16 is mixed in, and accurate calculation of the SOC by the current integration method cannot be performed. In this case, by performing the charging and warming up of the battery 10 exclusively, the calculation accuracy of the SOC can be ensured. Note that the ECU 80 ends the third SOC constant control when the battery temperature TB becomes the reference temperature Tth or more, and charges the battery 10 to CPmax (full charge). When the SOC of the battery 10 reaches CPmax, the ECU 80 ends the AC charging.

[0087] <Process performed by ECU>

[0088] Figure 5 is a flowchart showing steps of a process performed by the ECU at the time of AC charging. Figure 5 The process shown in the flowchart of FIG. 10 is started by the ECU 80 when an operation for starting AC charging is performed. The operation for starting AC charging is, for example, an operation on a charging start button (not shown) of the AC charging device 300, an operation on a charging start icon displayed on a display screen of a navigation device (not shown) of the vehicle 1, or an operation of connecting the connector 340 to the inlet 40. The operation for starting AC charging can be performed by a user or by the vehicle 1 itself. Figure 5 Each step (hereinafter, the step is simply referred to as "S") of the flowchart shown in FIG. 10 is explained in a case where it is implemented by software processing based on the ECU 80, but a part or all of it can be implemented by hardware (electronic circuit) made in the ECU 80.

[0089] In S1, the ECU 80 acquires the battery temperature TB from the temperature sensor 17, and determines whether the battery temperature TB is less than the reference temperature Tth. The ECU 80 causes the process to proceed to S2 in a case where it is determined that the battery temperature TB is the reference temperature Tth or more (NO in S1). The ECU 80 causes the process to proceed to S3 in a case where it is determined that the battery temperature TB is less than the reference temperature Tth (YES in S1).

[0090] In S2, the ECU 80 executes normal charging control. The normal charging control is control to charge the battery 10 to full charge (CPmax) by the supply electric power Pc supplied from the AC charging device 300 by AC charging. In a case where the battery temperature TB is the reference temperature Tth or more, the battery 10 is not warmed up, and thus the SOC constant control is not executed, and the battery 10 is charged to full charge.

[0091] In S3, the ECU 80 calculates the supply electric power Pc supplied from the AC charging device 300. Specifically, the ECU 80 calculates the supply electric power Pc from the rated current of the charging cable 330 and the application voltage applied from the AC charging device 300 to the inlet 40. For example, the rated current of the charging cable 330 can be identified on the basis of the duty ratio of the CPLT signal. In addition, in a case where the ECU 80 sets the current in AC charging, the set current can be set as the rated current. Note that the ECU 80 operates the potential of the CPLT signal, and causes the CCID 321 of the AC charging device 300 to be in a closed state, and applies the voltage from the AC charging device 300 to the inlet 40.

[0092] In S4, the ECU 80 reads the specification information of the heater 70 from the memory 82. The specification information of the heater 70 includes information of the consumption electric power Ph of the heater 70.

[0093] In S5, the ECU 80 compares the supply electric power Pc with the consumption electric power Ph of the heater 70, and determines whether the supply electric power Pc is greater than the maximum value Ph+α that can be obtained by the consumption electric power Ph. The ECU 80 causes the process to proceed to S6 in a case where it is determined that the supply electric power Pc is greater than the maximum value Ph+α (YES in S5). The ECU 80 causes the process to proceed to S7 in a case where it is determined that the supply electric power Pc is the maximum value Ph+α or less (NO in S5).

[0094] In S6, the ECU 80 selects the 1st SOC constant control in the SOC constant control, and causes the process to proceed to S10.

[0095] In S7, the ECU 80 determines whether the supplied electric power Pc is smaller than the minimum value Ph-α that can be obtained from the consumed electric power Ph. The ECU 80, when it is determined that the supplied electric power Pc is smaller than the minimum value Ph-α (YES in S7), causes the process to proceed to S8. The ECU 80, when it is determined that the supplied electric power Pc is the minimum value Ph-α or more (NO in S7), causes the process to proceed to S9.

[0096] In S8, the ECU 80 selects the 2nd SOC constant control among the SOC constant controls to perform, and causes the process to proceed to S10.

[0097] In S9, the ECU 80 selects the 3rd SOC constant control among the SOC constant controls to perform, and causes the process to proceed to S10.

[0098] In S10, the ECU 80 performs the SOC constant control selected in any one of S6, S8, and S9.

[0099] As described above, the vehicle 1 of the present embodiment has the three, the 1st SOC constant control to the 3rd SOC constant control, as the SOC constant control to perform when the battery 10 is warmed up at the time of AC charging. The ECU 80 selectively performs the 1st SOC constant control to the 3rd SOC constant control depending on the relationship between the supplied electric power Pc and the consumed electric power Ph of the heater 70.

[0100] In a case where the supplied electric power Pc is larger than the maximum value Ph+α that can be obtained from the consumed electric power Ph (Pc > Ph+α), the ECU 80 performs the 1st SOC constant control. Thereby, the ECU 80 can quickly warm up the battery 10 while suppressing the battery 10 from reaching overcharge due to an increase in the charging electric power PB of the battery 10 accompanying the stop of the heater 70.

[0101] In a case where the supplied electric power Pc is smaller than the minimum value Ph-α that can be obtained from the consumed electric power Ph (Pc < Ph-α), the ECU 80 performs the 2nd SOC constant control. With the 2nd SOC constant control, the supply of the supplied electric power Pc from the AC charging device 300 is continued all the time, whereby the decrease in the SOC at the time of driving of the heater 70 (at the time of warming up) can be slowed down. Thus, compared to a case where the supply of the supplied electric power Pc from the AC charging device 300 is stopped at the time of driving of the heater 70, the warming up time can be extended, and thus the battery temperature can be quickly warmed up to the reference temperature Tth or more. Therefore, the AC charging can be quickly completed. Thus, by performing the 2nd SOC constant control, the increase in the AC charging time can be suppressed.

[0102] In a case where the supplied electric power Pc is equal to or lower than the maximum value Ph+α and equal to or higher than the minimum value Ph-α (Ph-α ≤ Pc ≤ Ph+α), the ECU 80 executes the 3rd SOC constant control. In a case where the supplied electric power Pc and the consumed electric power Ph of the heater 70 are of the same degree, when both the charging of the battery 10 and the driving of the heater 70 are executed at the same time, the battery current IB (charge / discharge current) becomes small and the detection error of the current sensor 16 is mixed in, and accurate calculation of the SOC based on the current integration method cannot be performed. In this case, the charging and the temperature increase of the battery 10 are executed exclusively by the 3rd SOC constant control, and thus the calculation accuracy of the SOC can be ensured.

[0103] The embodiments disclosed this time are illustrative all aspects and are by no means limiting. It is the scope of the disclosure and not the above-described embodiments to be shown by the claims, and it is intended to include all modifications equivalent to the meaning and the scope of the claims.

Claims

1. A vehicle configured to perform external charging of its onboard battery using power supplied from a power source outside the vehicle, characterized in that, including: the battery; a temperature sensor that detects a temperature of the battery; a temperature raising device that raises a temperature of the battery; and a control device that controls the external charging and the temperature raising device, wherein, in execution of the external charging, the control device executes, during a period in which the temperature of the battery is less than a reference temperature, a state of charge control that drives the temperature raising device to raise the temperature of the battery while maintaining a state of charge of the battery within a predetermined range, in the state of charge control, in a case where the supply power is less than a minimum value of a consumption power of the temperature raising device, the control device maintains the state of charge of the battery within the predetermined range while intermittently operating the temperature raising device while the battery continuously receives the supply power.

2. The vehicle according to claim 1, wherein in the state of charge control, in a case where the state of charge of the battery decreases to a lower limit value of the predetermined range, the control device stops the temperature raising device and charges the battery with the supply power.

3. The vehicle according to claim 1 or 2, wherein in the state of charge control, in a case where the supply power is greater than a maximum value of the consumption power, the control device intermittently executes charging of the battery in a manner that the state of charge of the battery becomes the predetermined range while always operating the temperature raising device.

4. The vehicle according to any one of claims 1 to 3, wherein in the state of charge control, in a case where the supply power is less than the maximum value of the consumption power and greater than the minimum value of the consumption power, the control device exclusively executes (i) charging of the battery with the supply power and (ii) operation of the temperature raising device with power of the battery without receiving the supply power in a manner that the state of charge of the battery becomes the predetermined range.

5. The vehicle according to any one of claims 1 to 4, wherein an upper limit value of the predetermined range is set to a value that does not cause overcharging of the battery due to an increase in charging power of the battery in execution of the state of charge control in which the temperature raising device is stopped, based on the supply power and the consumption power.

6. A method of external charging that charges a battery mounted in a vehicle with supply power supplied from a power supply outside the vehicle, the battery being capable of being raised in temperature by a temperature raising device, the method of external charging characterized by comprising: in execution of the external charging, during a period in which a temperature of the battery is less than a reference temperature, executing a state of charge control that drives the temperature raising device to raise the temperature of the battery while maintaining a state of charge of the battery within a predetermined range, in the state of charge control, in a case where the supply power is less than a minimum value of a consumption power of the temperature raising device, maintaining the state of charge of the battery within the predetermined range while intermittently operating the temperature raising device while the battery continuously receives the supply power. ​ 7. The method according to claim 6, wherein the external charging and the temperature raising device are controlled by a control device provided in the vehicle.

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