Vehicle

Abstract

To early raise a temperature of a power storage device to a sufficient temperature at a start of charging of the power storage device while suppressing a decrease in energy efficiency.SOLUTION: A power storage system includes: a power storage device; a first heater and second heater capable of heating the power storage device, using electric power; and a control device. The first heater is disposed more away from the power storage device than the second heater. The control device can execute: first heating control for heating the power storage device, using both the first heater and second heater; and second heating control for heating the power storage device, using only the second heater of the first heater and second heater. The control device executes the first heating control when a predetermined heating condition is met at a start of charging of the power storage device. Then, the control device executes the second heating control instead of the first heating control when a predetermined switching condition is met during charging of the power storage device and during execution of the first heating control.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a power storage system and a vehicle equipped with the power storage system.

Background Art

[0002] Japanese Patent Application Laid-Open No. 2020-113383 (Patent Document 1) discloses a power storage system (specifically, a power storage battery charging system) that heats a power storage battery with an electric heater provided around the power storage battery. In this power storage system, in addition to the electric heater, the power storage battery is also heated by a charger by utilizing the heat generated by the charger when it is energized. In the power storage system described in Patent Document 1, the power storage battery is heated to increase the effective capacity of the power storage battery of the electric vehicle when the electric vehicle starts or is charging.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the technology described in Patent Document 1, by utilizing the heat generation of the charger, the amount of heat (heating amount) for heating the power storage device is increased without increasing the number of electric heaters used for heating the power storage device. In such a technology, since the power storage device is heated using an electric heater and a charger provided around the power storage device, the energy loss may be small. However, the heating amount by the charger is smaller than the heating amount by the electric heater. Therefore, a sufficient heating amount is not always obtained.

[0005] For example, if the power storage device is in a low-temperature state at the start of charging, the charging power is limited due to a decrease in the current that the power storage device can accept, and there may arise a problem that the charging time of the power storage device (i.e., the time required until the charging of the power storage device is completed) becomes long. In order to shorten the charging time of the power storage device, it is required to raise the temperature of the power storage device in the low-temperature state to a sufficient temperature at an early stage at the start of charging of the power storage device. It is difficult to raise the temperature of the power storage device in the low-temperature state to a sufficient temperature at an early stage by the technique described in the above Patent Document 1.

[0006] The present disclosure has been made to solve the above problems, and an object thereof is to raise the temperature of the power storage device to a sufficient temperature at an early stage at the start of charging of the power storage device while suppressing a decrease in energy efficiency.

Means for Solving the Problems

[0007] The power storage system according to the present disclosure includes a power storage device, a first heater and a second heater configured to be able to heat the power storage device using power, and a control device. The first heater is arranged farther from the power storage device than the second heater. The control device is configured to be able to execute a first heating control for heating the power storage device using both the first heater and the second heater, and a second heating control for heating the power storage device using only the second heater among the first heater and the second heater. The control device executes the first heating control when a predetermined heating condition is satisfied at the start of charging of the power storage device. Then, when a predetermined switching condition is satisfied during charging of the power storage device and during execution of the first heating control, the control device executes the second heating control instead of the first heating control.

[0008] In a power storage system, it is rare for a plurality of electric heaters to be arranged around the power storage device. However, there are many power storage systems in which one electric heater is arranged near the power storage device and another electric heater is arranged at a position far from the power storage device. Therefore, in the above configuration, the power storage device is heated using a plurality of electric heaters (the first and second heaters). However, the energy consumed to raise the temperature of the power storage device tends to be more in the electric heater (the first heater) located at a position farther from the power storage device than in the electric heater (the second heater) existing near the power storage device. A part of the energy (heat) generated at a position far from the power storage device is lost before being transmitted to the power storage device. For this reason, it is considered that the heating of the power storage device by the second heater is more energy-efficient than the heating of the power storage device by the first heater.

[0009] In this regard, when a predetermined heating condition is satisfied at the start of charging of the power storage device, the control device executes first heating control. According to such control, it becomes possible to execute the first heating control as needed at the start of charging of the power storage device, and to raise the temperature of the power storage device to a sufficient temperature early by the first and second heaters. The above-mentioned predetermined heating condition may be satisfied when the heating amount is not sufficient with only the second heater.

[0010] Furthermore, when a predetermined switching condition is satisfied, the control device switches from the first heating control to the second heating control. According to such control, after the temperature of the power storage device is raised to a sufficient temperature by the first heating control, it becomes possible to adjust the temperature of the power storage device (for example, keep it warm) by the second heating control. The above-mentioned predetermined switching condition may be satisfied when a sufficient heating amount can be ensured with only the second heater. By switching from the first heating control to the second heating control, the heating of the power storage device by the first heater, which is relatively low in energy efficiency, is stopped, and only the heating of the power storage device by the second heater, which is relatively high in energy efficiency, is continued. Thereby, a decrease in energy efficiency is suppressed.

Effect of the Invention

[0011] According to the present disclosure, it is possible to quickly raise the temperature of the power storage device to a sufficient temperature at the start of charging of the power storage device while suppressing a decrease in energy efficiency.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0013] Embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and their description will not be repeated.

[0014] FIG. 1 is a diagram showing a schematic configuration of a vehicle according to this embodiment. As shown in FIG. 1, the vehicle 1 is an electric vehicle (xEV) equipped with the power storage system according to this embodiment. The vehicle 1 is, for example, a four-wheel BEV (battery electric vehicle). However, the vehicle 1 may be another electric vehicle such as a plug-in hybrid vehicle. Further, the vehicle 1 may be configured to be capable of non-contact charging. The number of wheels is also arbitrary, and may be three wheels or five or more wheels.

[0015] Vehicle 1 includes a thermal management circuit 100 and an ECU (Electronic Control Unit) 500. The ECU 500 includes a processor 501, a RAM (Random Access Memory) 502, and a storage device 503. As the processor 501, for example, a CPU (Central Processing Unit) can be adopted. The storage device 503 is configured to be able to store the stored information. In addition to programs, information (maps, mathematical formulas, various parameters, etc.) used in the programs is stored in the storage device 503. In this embodiment, by the processor 501 executing the programs stored in the storage device 503, various controls in the ECU 500 (see FIGS. 3 and 4, for example) are executed. However, the various controls in the ECU 500 may be executed by hardware (electronic circuits) instead of software.

[0016] The thermal management circuit 100 is configured to perform thermal management of the vehicle 1 using a heat medium. The thermal management circuit 100 includes a first circuit 110, a second circuit 120, and a third circuit 130. Further, the thermal management circuit 100 includes a capacitor 140, a refrigeration cycle 150, a chiller 160, a five-way valve 310, and a reservoir tank (R / T) 320. The five-way valve 310 and the reservoir tank 320 are shared by the second circuit 120 and the third circuit 130. Further, the capacitor 140, the refrigeration cycle 150, and the chiller 160 are arranged between the first circuit 110 and the second circuit 120 and function as an example of the "heat transfer mechanism" according to the present disclosure.

[0017] The first circuit 110 includes a first flow path through which a first heat medium flows. The first circuit 110 includes a pump 111, an electric heater 112 (first heater), a three-way valve 113, a heater core 114, a reservoir tank (R / T) 115, and a radiator 118. The three-way valve 113 switches the path of the first heat medium. The pump 111 circulates the first heat medium through the first circuit 110. Specifically, the pump 111 passes the first heat medium sucked up from the reservoir tank 115 through the condenser 140, the electric heater 112, the heater core 114 or the radiator 118 connected by the three-way valve 113 in this order, and then returns it to the reservoir tank 115. The first heat medium exchanges heat with each device during passage. The pump 111, the electric heater 112, and the three-way valve 113 are controlled by the ECU 500. The radiator 118 functions as a heat exchanger. Heat exchange occurs between the first heat medium flowing through the first circuit 110 and the outside air by the radiator 118.

[0018] The five-way valve 310 switches the path of the second heat medium. The five-way valve 310 has five ports P1 to P5. The ECU 500 controls the five-way valve 310 to be in any one of the first to fifth connection patterns described below. Hereinafter, the ports P1, P2, P3, P4, and P5 may be simply denoted as "P1", "P2", "P3", "P4", and "P5", respectively.

[0019] In the first connection pattern, P1 and P2 are connected, P3 and P4 are connected, and P5 is in a non-connected state. In the second connection pattern, P1 and P2 are connected, P4 and P5 are connected, and P3 is in a non-connected state. In the third connection pattern, P1 and P5 are connected, P3 and P4 are connected, and P2 is in a non-connected state. In the fourth connection pattern, P2 and P4 are connected, P1 and P3 are connected, and P5 is in a non-connected state. In the fifth connection pattern, P2 and P4 are connected, P1 and P5 are connected, and P3 is in a non-connected state.

[0020] Flow paths 120a and 120b are respectively connected to ports P1 and P2 of the five-way valve 310. Flow path 120a is a flow path connecting port P1 and the reservoir tank 320. Flow path 120b is a flow path connecting port P2 and the reservoir tank 320. When P1 and P2 of the five-way valve 310 are connected (for example, the first and second connection patterns), a second circuit 120 including flow paths 120a and 120b is formed.

[0021] A pump 121 and a chiller 160 (described later) are arranged in flow path 120a. A battery 200 and an electric heater 220 (second heater) are arranged in flow path 120b. The pump 121 circulates a second heat medium through the second circuit 120. Specifically, the pump 121 passes the second heat medium sucked up from the reservoir tank 320 through the chiller 160, the five-way valve 310, the electric heater 220, and the battery 200 in this order, and then returns it to the reservoir tank 320. The second heat medium exchanges heat with each device during passage. A second heat medium that exchanges heat with the battery 200 flows in flow path 120b. The pump 121 and the electric heater 220 are controlled by the ECU 500. A BMS (Battery Management System) 210 for monitoring the state of the battery 200 is provided in the battery 200.

[0022] Flow paths 130b and 130a are respectively connected to ports P3 and P4 of the five-way valve 310. Flow paths 130b and 130a are flow paths connecting port P3 and P4 and the reservoir tank 320 respectively. When P3 and P4 of the five-way valve 310 are connected (for example, the first and third connection patterns), a third circuit 130 including flow paths 130a and 130b is formed.

[0023] In this embodiment, a heat medium (second heat medium) of the same type as the heat medium circulating in the second circuit 120 circulates in the third circuit 130. Note that the first heat medium circulating in the first circuit 110 is a heat medium of a type different from the second heat medium. Also, the third heat medium used in the refrigeration cycle 150 described later is also a heat medium of a type different from the first and second heat media. For example, the first heat medium may be a known heat medium for heating. The second heat medium may be insulating oil or antifreeze. The third heat medium may be a known heat medium for a refrigeration cycle. However, it is not limited to this, and each of the first to third heat media can be appropriately changed.

[0024] In the flow path 130a, a pump 131, an SPU (Smart Power Unit) 132, a front motor PCU (Fr-PCU) 133, a rear motor PCU (Rr-PCU) 134, and oil coolers (O / C) 135, 136 are arranged. The pump 131 circulates the second heat medium through the third circuit 130. Specifically, the pump 131 passes the second heat medium sucked from the reservoir tank 320 through the SPU 132, the Fr-PCU 133, the Rr-PCU 134, the oil cooler 135, the oil cooler 136, and the five-way valve 310 in this order, and then returns it to the reservoir tank 320. The second heat medium exchanges heat with each device during passage. The SPU 132 functions as an in-vehicle charger / discharger (charger and discharger) for the battery 200. However, it is not essential for the vehicle 1 to have an external power supply function (e.g., V2H function). The SPU 132 includes, for example, a power conversion circuit. PCU means "Power Control Unit". Each of the Fr-PCU 133 and the Rr-PCU 134 drives an MG (motor generator), not shown, using the power supplied from the battery 200. The torque output by the MG rotates the drive wheels of the vehicle 1 via a transaxle (T / A). The battery 200 functions as a traction battery. Each PCU may include a bidirectional inverter. The SPU 132 and each PCU are controlled by the ECU 500. The T / A functions as a power transmission mechanism. Each of the oil coolers 135, 136 cools the oil supplied to the T / A of the vehicle 1 by an electric oil pump (EOP). The second heat medium flowing through the oil coolers 135, 136 exchanges heat with the oil for the T / A. One or more temperature sensors for detecting the temperature of the second heat medium flowing through the flow path 130a may be provided at a predetermined location (e.g., near each PCU).

[0025] A flow path 170a is connected to port P5 of the five-way valve 310. The flow path 170a is a flow path that connects port P5 and the reservoir tank 320. A radiator 170 is provided in the flow path 170a. The radiator 170 functions as a heat exchanger. Heat exchange occurs between the heat medium flowing through the flow path 170a and the outside air by means of the radiator 170. The ECU 500 can cool the second heat medium by heat exchange in the radiator 170 by connecting the flow path 120a or 130a to the flow path 170a by means of the five-way valve 310.

[0026] A third heat medium circulates in the refrigeration cycle 150. The refrigeration cycle 150 includes a compressor 151, an electric expansion valve 152, an evaporator 153, an evaporative pressure regulator (EPR) 154, and an electric expansion valve 155. The condenser 140 is connected to both the first circuit 110 and the refrigeration cycle 150 and functions as a heat exchanger. Heat exchange occurs between the first heat medium flowing through the first circuit 110 and the third heat medium circulating in the refrigeration cycle 150 by means of the condenser 140. The chiller 160 is connected to both the refrigeration cycle 150 and the flow path 120a and functions as a heat exchanger. When the five-way valve 310 is in the first or second connection pattern, heat exchange occurs between the third heat medium circulating in the refrigeration cycle 150 and the second heat medium flowing through the second circuit 120 by means of the chiller 160. Thus, the condenser 140, the refrigeration cycle 150, and the chiller 160 are configured to effect heat transfer between the first heat medium flowing through the first circuit 110 and the second heat medium flowing through the second circuit 120. The refrigeration cycle 150 (including the compressor 151 and various valves) is controlled by the ECU 500. One or more pressure sensors and one or more temperature sensors for detecting the pressure and temperature of the third heat medium flowing through the refrigeration cycle 150 may be provided at predetermined locations.

[0027] FIG. 2 is a diagram showing the configuration of the battery 200 and the BMS 210. Referring to FIG. 2, the battery 200 is an assembled battery formed by connecting N cells 2-1 to 2-N. N is a natural number of 2 or more, and may be less than 100 or 100 or more. The cells 2-1 to 2-N are connected in series. However, the connection mode of the cells in the assembled battery is not limited to series connection, and may include parallel connection. The electric heater 220 is disposed near the battery 200 and configured to heat the second heat medium flowing through the flow path 120b.

[0028] The BMS 210 includes a current sensor 211 that detects the current flowing through the battery 200 (assembled battery), voltage sensors 212-1 to 212-N and temperature sensors 213-1 to 213-N respectively corresponding to the cells 2-1 to 2-N, and a temperature sensor 215 that detects the ambient temperature of the battery 200. The temperature sensor 215 detects the temperature of the second heat medium flowing through the flow path 120b near the battery 200. The detection results by each sensor are input to the ECU 500.

[0029] Based on the signals from each sensor, the ECU 500 can acquire the current of the battery 200, the ambient temperature of the battery 200, and the voltage and temperature of each cell of the battery 200. Further, the ECU 500 can calculate the SOC (State Of Charge) of each cell from the detection results by each sensor. The SOC represents the ratio of the current stored power to the fully charged state stored power, for example, expressed as 0 to 100%. Note that the configuration of the BMS 210 can be changed as appropriate.

[0030] Vehicle 1 is equipped with an inlet 250. The inlet 250 functions as a charging port. The EVSE (Electric Vehicle Supply Equipment) 800 includes a charging cable 810 that extends outward from the main body of the EVSE 800. The connector 820 (tip) of the charging cable 810 is configured to be detachable from the inlet 250. When the connector 820 of the charging cable 810 connected to the main body of the EVSE 800 is connected to the inlet 250 of the parked vehicle 1, the vehicle 1 is in an electrically connected state (plugged-in state) with the EVSE 800. The EVSE 800 and the power grid PG are electrically connected. Therefore, the plugged-in vehicle 1 is electrically connected to the power grid PG. The power grid PG is a power grid constructed by power transmission and distribution facilities. A plurality of power generation plants are connected to the power grid PG.

[0031] When the plugged-in vehicle 1 performs external charging (charging of the battery 200 with power from outside the vehicle), the power supplied from the power grid PG is input to the inlet 250 via the EVSE 800. The SPU 132 uses the power input to the inlet 250 to generate charging power according to an instruction from the ECU 500 and inputs the generated charging power to the battery 200. The EVSE 800 supplies, for example, alternating current power to the inlet 250. The SPU 132 may perform AC / DC conversion and voltage transformation to generate the charging power. However, the power supply method of the EVSE 800 is not limited to the AC method and may be the DC method.

[0032] The air conditioner 2 mounted on the vehicle 1 performs air conditioning (heating and cooling) inside the vehicle 1 using the first circuit 110 and the refrigeration cycle 150. The electric heater 112 heats the first heat medium in the first circuit 110 according to a command from the ECU 500. The heater core 114 warms the air inside the vehicle compartment by heat exchange with the first heat medium. Also, the evaporator 153 of the refrigeration cycle 150 cools the air inside the vehicle compartment.

[0033] The battery 200 supplies power to various devices included in the thermal management circuit 100 shown in FIG. 1. The battery 200 may supply power to the electric heater 112 via a first power conversion circuit (for example, a DC / DC converter) not shown. The battery 200 may supply power to the electric heater 220 via a second power conversion circuit (for example, a DC / DC converter) not shown. In this embodiment, the drive voltage of the electric heater 112 is higher than the drive voltage of the electric heater 220. The maximum heat generation amount of the electric heater 112 is larger than that of the electric heater 220. The energy consumption at the time of maximum heat generation of the electric heater 112 is larger than that of the electric heater 220. Note that at least one of the various devices included in the thermal management circuit 100 may receive power supply from an in-vehicle battery other than the battery 200 (for example, an accessory battery not shown).

[0034] FIG. 3 is a flowchart showing the processing related to the charging control executed by the ECU 500. Each step in the flowchart is denoted by "S". The processing shown in this flowchart is started, for example, when the start condition for the above external charging (plug-in charging) is satisfied. Specifically, when the vehicle 1 is in the plug-in state (see FIG. 2), the start condition for external charging is satisfied, and the following processing flow (S11 to S19) may be started. However, when a failure of the thermal management circuit 100 is detected as a result of the failure diagnosis by the ECU 500, the start condition for external charging may not be satisfied.

[0035] Referring to FIG. 3, in S11, the ECU 500 acquires EVSE information indicating the specifications of the power supply equipment (for example, EVSE 800) connected to the vehicle 1 and battery temperature information indicating the current temperature of the battery 200. The EVSE information includes information indicating the output performance (for example, rated output) of the power supply equipment. The rated output corresponds to the maximum power value (kW) that the power supply equipment can output as defined in the specifications. The ECU 500 may receive the EVSE information from the power supply equipment by communicating with the power supply equipment connected to the vehicle 1. The battery temperature information includes the ambient temperature (temperature of the second heat medium) of the battery 200 detected by the BMS 210. Hereinafter, the rated output of the power supply equipment acquired in S11 is also referred to as "EVSE output". Also, the ambient temperature of the battery 200 acquired in S11 is also referred to as "battery temperature".

[0036] In S12, the ECU 500 determines initial heater control conditions based on the information acquired in S11. Specifically, the storage device 503 stores a map M1 in advance. The map M1 outputs heater control conditions according to the input values when the EVSE output and the battery temperature are input. The heater control conditions include identification information of the heater to be driven, the driving amount (heat generation amount) of the heater, and the target temperature used in heater control. The heater driven during external charging of the battery 200 is at least one of the electric heaters 112 and 220. Specifically, during external charging of the battery 200, the ECU 500 performs a first heating control (denoted as "heating A" in the map M1) for heating the battery 200 using both the electric heaters 112 and 220, and a second heating control (denoted as "heating B" in the map M1) for heating the battery 200 using only the electric heater 220 among the electric heaters 112 and 220, and executes either one of them as necessary. Also, the ECU 500 may adopt "no heater drive" (that is, neither of the electric heaters 112 and 220 is driven) during external charging of the battery 200 (denoted as "-" in the map M1). Hereinafter, the initial heater control conditions may be simply referred to as "initial conditions".

[0037] The map M1 shown in FIG. 3 defines initial conditions suitable for the cases where the EVSE output is 3.3 kW, 7 kW, and 11 kW, respectively. For each of the EVSE outputs of 11 kW and 7 kW, when the battery temperature is equal to or higher than the first threshold, "no heater drive" is defined as the initial condition; when the battery temperature is higher than the second threshold and lower than the first threshold, the second heating control is defined as the initial condition; and when the battery temperature is lower than the second threshold, the first heating control is defined as the initial condition. However, the first threshold (e.g., 5°C) and the second threshold (e.g., -10°C) for the EVSE output of 11 kW are higher than the first threshold (e.g., 0°C) and the second threshold (e.g., -15°C) for the EVSE output of 7 kW, respectively. For the rated output of 3.3 kW, when the battery temperature is equal to or higher than a predetermined value (e.g., -5°C), "no heater drive" is defined as the initial condition; and when the battery temperature is lower than the predetermined value, the second heating control is defined as the initial condition.

[0038] The calorific value of the electric heater 220 under the initial conditions is the same (e.g., 700 W) for any of the EVSE outputs of 11 kW, 7 kW, and 3.3 kW. Regarding the calorific value of the electric heater 112 under the initial conditions, the value for the EVSE output of 11 kW (e.g., 7000 W) is higher than the value for the EVSE output of 7 kW (e.g., 5000 W). Regarding the first heating control, the calorific value of the electric heater 112 may be set to be five times or more the calorific value of the electric heater 220.

[0039] The target temperature in the heater control increases as the EVSE output increases. The first target temperature for the first heating control is, for example, 10°C and 5°C for the EVSE outputs of 11 kW and 7 kW, respectively. The second target temperature for the second heating control is, for example, 5°C, 0°C, and -5°C for the EVSE outputs of 11 kW, 7 kW, and 3.3 kW, respectively. Each target temperature may be predetermined based on the temperature characteristics of the chargeable power of the battery 200. In the low temperature region where the temperature is lower than 0°C, the chargeable power of the battery 200 increases as the temperature of the battery 200 increases. In this embodiment, the second target temperature is lower than the first target temperature.

[0040] As described above, according to the map M1 shown in FIG. 3, as the EVSE output increases, the number of heaters to be driven increases, the driving amount of the heaters increases, and the target temperature increases. In S12, the ECU 500 uses such a map M1 to determine the initial conditions according to the EVSE output and the battery temperature acquired in S11. When the rated output of the power supply facility connected to the vehicle 1 does not match any of 3.3 kW, 7 kW, and 11 kW, the ECU 500 may adopt the initial conditions corresponding to the closest rated output (any of 3.3 kW, 7 kW, and 11 kW).

[0041] In the subsequent S13, while the ECU 500 executes the thermal management (first heating control, second heating control, or no heater driving) of the battery 200 according to the initial conditions determined in S12, the ECU 500 executes the external charging of the battery 200. In this embodiment, the ECU 500 drives the pumps 111, 121, and 131 in a state where the five-way valve 310 is in the first connection pattern (for example, see FIG. 5), and controls the electric heaters 112 and 220 according to the conditions determined in S12. For example, in the first heating control, the heat generated by the electric heater 112 is transmitted to the battery 200 through the first heat medium, the capacitor 140, the third heat medium (refrigeration cycle 150), the chiller 160, and the second heat medium, and the heat generated by the electric heater 220 is transmitted to the battery 200 through the second heat medium. Thereby, the temperature of the battery 200 rises. Further, the ECU 500 controls the SPU 132 so that the battery 200 is charged by the power supplied from the power supply facility outside the vehicle. Thereby, the SOC of the battery 200 rises.

[0042] In the subsequent S14, the ECU 500 acquires the current SOC of the battery 200 detected by the BMS 210. Subsequently, in S15, the ECU 500 determines whether to end the charging based on whether the charging end condition is satisfied. The charging end condition is satisfied, for example, when the SOC of the battery 200 reaches the target value. The target value may be 100% (the SOC value indicating full charge). Note that the charging end condition can be changed as appropriate.

[0043] If the charging end condition is not satisfied (NO in S15), the process proceeds to S16. In S16, the ECU 500 acquires the temperature of each cell of the current battery 200 detected by the BMS 210. Hereinafter, among the temperatures of each cell acquired in S16, the highest cell temperature is referred to as the "highest cell temperature", and the lowest cell temperature is referred to as the "lowest cell temperature".

[0044] In the subsequent S17, the ECU 500 determines whether the electric heater 112 is operating. If the first heating control is being executed in S13, it is determined as YES in S17 and the process proceeds to S18. On the other hand, if the first heating control is not being executed in S13, it is determined as NO in S17 and the process proceeds to S19. FIG. 4 is a diagram for explaining S18 and S19. The first heater control (S18) includes S181 to S184. The second heater control (S19) includes S191 to S193.

[0045] Referring to FIG. 4, in the first heater control (S18), in S181, the ECU 500 determines whether the lowest cell temperature (S16 in FIG. 3) is equal to or higher than the first target temperature (initial condition). If the lowest cell temperature is lower than the first target temperature (NO in S181), the electric heater 112 continues to operate under the initial conditions and the process proceeds to S19. In this case, the first heating control is continued. On the other hand, if the lowest cell temperature is equal to or higher than the first target temperature (YES in S181), in S182, the ECU 500 controls the electric heater 112 so that it operates with a heat generation amount smaller than the initial conditions (weak operation). Thereafter, the process proceeds to S183.

[0046] In S183, the ECU 500 determines whether the operating time of the electric heater 112 (the elapsed time since the start of operation) has exceeded a predetermined threshold value. The threshold value may be a limit value (allowable operating time) determined according to the component durability of the electric heater 112. If the operating time of the electric heater 112 does not exceed the above threshold value (NO in S183), the process proceeds to S19 with the electric heater 112 in the weak operation state (S182). In this case, the first heating control is continued. On the other hand, if the operating time of the electric heater 112 exceeds the above threshold value (YES in S183), the ECU 500 stops the electric heater 112 in S184. As a result, the control switches from the first heating control to the second heating control. Then, the process proceeds to S19.

[0047] In the second heater control (S19), the ECU 500 determines in S191 which of the first heating control, the second heating control, and no heater drive is used for heat management. If it is determined in S191 that there is "no heater drive" (initial condition), the process returns to S13 in FIG. 3. If it is determined in S191 that it is the "first heating control", the ECU 500 controls the electric heater 220 with the heat generation amount under the initial condition (fixed condition) in S192. Then, the process returns to S13 in FIG. 3, and the ECU 500 performs external charging of the battery 200 together with the first heating control determined in S18 and S19 according to the determined conditions. If it is determined in S191 that it is the "second heating control", the ECU 500 controls the electric heater 220 based on the maximum cell temperature (S16 in FIG. 3) and the second target temperature (initial condition) in S193. Then, the process returns to S13 in FIG. 3, and the ECU 500 performs external charging of the battery 200 together with the second heating control determined in S193 according to the determined conditions.

[0048] In FIG. 4, time chart Ex1 shows the state transition (first operation example) when the above first and second heater controls are executed under the initial conditions corresponding to the EVSE output “7 kW” and the battery temperature “−30° C.” In time chart Ex1, lines L1, L2, L11, L12, L13, and L20 indicate the first target temperature, the second target temperature, the battery temperature, the highest cell temperature, the lowest cell temperature, and the SOC, respectively. Also, regions E1, E2, E3, and E4 indicate the amounts of electric power consumed by the drive of the electric heater 112, the drive of the electric heater 220, the charging of the battery 200, and the energy loss (such as heat dissipation) among the electric power supplied from the power supply facility to the vehicle 1. “t” in the time chart means timing.

[0049] In time chart Ex1, the first heating control is executed according to the initial conditions. Thereafter, at t11, the lowest cell temperature (line L13) reaches the first target temperature (line L1), and the electric heater 112 enters the weak operation state. At t12, the operation time of the electric heater 112 exceeds the threshold value, and the electric heater 112 stops. As a result, the second heating control is executed instead of the first heating control. Also, since the highest cell temperature (line L12) is higher than the second target temperature (line L2), the ECU 500 sets the electric heater 220 to the standby state (substantially stopped state). Thereafter, at t13, the ECU 500 operates the electric heater 220 again to keep the highest cell temperature at the second target temperature.

[0050] Referring to FIG. 3 again, in S13, thermal management of the battery 200 and external charging are performed. When the charging end condition is satisfied (YES in S15), the series of processes shown in FIG. 3 ends. FIG. 5 is a diagram showing a second operation example of the power storage system according to this embodiment. The time chart Ex2 shows the state transition (second operation example) when the first and second heater controls shown in FIGS. 3 and 4 are executed under the initial conditions corresponding to the EVSE output "11 kW" and the battery temperature "-20°C". The lines and regions in the time chart Ex2 shown in FIG. 5 conform to the time chart Ex1 shown in FIG. 4. In the time chart Ex2, the first heating control is executed according to the initial conditions. As shown in FIG. 5, the ECU 500 performs thermal management of the battery 200 and external charging (S13 in FIG. 3) with the five-way valve 310 in the first connection pattern. Then, during the execution of the first heating control, the charging end condition is satisfied without the switching condition being satisfied. Thereby, the thermal management of the battery 200 and external charging end.

[0051] As described above, the thermal management method according to this embodiment includes the processes shown in FIGS. 3 and 4. The power storage system according to this embodiment includes a power storage device (battery 200), a first heater (electric heater 112) and a second heater (electric heater 220) configured to be able to heat the power storage device using electric power, and a control device (ECU 500). The electric heater 112 is arranged farther from the battery 200 than the electric heater 220. The ECU 500 executes the first heating control when a predetermined heating condition is satisfied at the start of charging of the battery 200. The ECU 500 executes the second heating control instead of the first heating control when a predetermined switching condition is satisfied during charging of the battery 200 and during the execution of the first heating control.

[0052] The heating of the battery 200 by the electric heater 220 is more energy-efficient than the heating of the battery 200 by the electric heater 112. According to the above control, at the start of charging of the battery 200, the first heating control is executed as necessary, and the electric heaters 112 and 220 can quickly raise the temperature of the battery 200 to a sufficient temperature. Further, according to the above control, after the temperature of the battery 200 has been raised to a sufficient temperature by the first heating control, the electric heater 112 is stopped, and the temperature of the battery 200 can be adjusted (for example, kept warm) by the second heating control. Thereby, a decrease in energy efficiency is suppressed.

[0053] In this embodiment, the ECU 500 controls the heating amount by the electric heater 112 based on the temperature of the battery 200 during the execution of the first heating control (S181, S182 in FIG. 4). Then, when a predetermined time has elapsed since the start of the first heating control (YES in S183 in FIG. 4), the above-described predetermined switching condition is satisfied. According to such a configuration, it becomes easy to control the heating amount by the electric heater 112 to an appropriate amount (an amount necessary and sufficient for raising the temperature of the battery 200) during the execution of the first heating control. Also, if the first heating control is continued for a long time, the energy efficiency may deteriorate. In this regard, in the above configuration, at the timing when a predetermined time has elapsed since the start of the first heating control, the ECU 500 switches from the first heating control to the second heating control. Thereby, a decrease in energy efficiency is suppressed.

[0054] The vehicle 1 shown in FIGS. 1 and 2 includes a first flow path (first circuit 110) through which a first heat medium flows, an air conditioner 2 that performs air conditioning inside the vehicle 1 by heat exchange with the first heat medium, a second flow path (flow path 120b) through which a second heat medium that exchanges heat with the battery 200 flows, and a heat transfer mechanism (condenser 140, refrigeration cycle 150, chiller 160) that performs heat transfer between the first heat medium and the second heat medium. The electric heater 112 is provided in the first flow path. The electric heater 220 is provided in the second flow path. With such a configuration, heat management of the vehicle 1 can be suitably performed by the first flow path (first heat medium), the second flow path (second heat medium), and the heat transfer mechanism. Further, since the electric heater 112 for the air conditioner 2 is used for heating the battery 200, it is not necessary to add a dedicated electric heater for heating the battery 200.

[0055] Also, when starting charging of the battery 200 using a power supply facility (for example, EVSE 800), the ECU 500 of the vehicle 1 determines whether or not the above-described predetermined heating conditions are satisfied using the output performance (for example, rated output) of the power supply facility and the temperature of the second heat medium. Specifically, the map M1 shown in FIG. 3 defines the heating conditions. According to such a configuration, it becomes easier to accurately determine whether or not it is necessary to execute the first heating control in which the energy consumption is larger than that of the second heating control when starting charging of the battery 200. The temperature of the second heat medium corresponds to the ambient temperature of the battery 200. When the output performance of the power supply facility is lower than the rated output due to a disaster (for example, lightning strike) or an abnormality of the generator, etc., the ECU 500 may acquire the latest output performance (for example, maximum output value) of the power supply facility and use the latest output performance instead of the rated output.

[0056] Each of the above-described heating conditions and switching conditions can be changed as appropriate. The processing flows shown in FIGS. 3 and 4 can be changed as appropriate. For example, depending on the purpose, the order of the processing may be changed, unnecessary steps may be omitted, or the content of any of the processing may be changed.

[0057] FIG. 6 is a diagram showing a modified example of the process shown in FIG. 4. The lines and regions in the time chart Ex3 (the third operation example) shown in FIG. 6 conform to the time chart Ex1 shown in FIG. 4. In S18A shown in FIG. 6, S182 and S183 in the process shown in FIG. 4 are omitted. In the time chart Ex3, the first heating control is executed according to the initial conditions, and at t30, the minimum cell temperature (line L13) reaches the first target temperature (line L1) (YES in S181). As a result, the switching condition is satisfied, and the electric heater 112 stops in S184. In the second heating control, the ECU 500 controls the electric heater 220 so that the maximum cell temperature (line L12) approaches the second target temperature (line L2) (S193).

[0058] The power storage system according to the above modified example includes a cell temperature sensor (temperature sensors 213-1 to 213-N shown in FIG. 2) that detects the cell temperature of each of the plurality of cells included in the battery 200 (battery pack). Then, when the lowest cell temperature in the battery 200 becomes equal to or higher than a predetermined temperature during charging of the battery 200 and during execution of the first heating control (YES in S181), the above-described switching condition is satisfied. Therefore, it becomes possible to quickly raise the temperature of all the cells included in the battery pack to a predetermined temperature (for example, a temperature at which the cells are appropriately charged).

[0059] The embodiments disclosed this time should be considered as illustrative in all respects and not restrictive. The scope of the present disclosure is indicated by the claims rather than the description of the above embodiments, and is intended to include all modifications within the meaning and scope equivalent to the claims.

Description of Reference Numerals

[0060] 1 Vehicle, 2 Air conditioner, 2-1 to 2-N Cells, 100 Thermal management circuit, 110 First circuit, 112 Electric heater, 120 Second circuit, 130 Third circuit, 140 Capacitor, 150 Refrigeration cycle, 160 Chiller, 200 Battery, 220 Electric heater, 500 ECU, 800 EVSE, PG Power system.

Claims

A vehicle comprising a power storage system, wherein: the power storage system includes: a power storage device; a first heater and a second heater configured to heat the power storage device using electric power; and a control device, the vehicle further includes: a first flow path through which a first heat medium flows; an air conditioner that performs air conditioning inside the vehicle by exchanging heat with the first heat medium; a second flow path through which a second heat medium that exchanges heat with the power storage device flows; and a heat transfer mechanism that transfers heat between the first heat medium and the second heat medium, the first heater is provided in the first flow path, the second heater is provided in the second flow path, the control device is configured to be capable of executing: a first heating control for heating the power storage device using both the first heater and the second heater; and a second heating control for heating the power storage device using only the second heater among the first heater and the second heater, when a predetermined heating condition is satisfied at the start of charging of the power storage device, the control device executes the first heating control, and when a predetermined switching condition is satisfied during charging of the power storage device and during execution of the first heating control, the control device executes the second heating control instead of the first heating control, charging of the power storage device is charging of the power storage device by electric power supplied from a power supply facility outside the vehicle, the control device determines whether or not the predetermined heating condition is satisfied using the output performance of the power supply facility and the temperature of the second heat medium at the start of charging of the power storage device using the power supply facility. A vehicle.

2. During execution of the first heating control, the control device controls the heating amount by the first heater based on the temperature of the power storage device. The vehicle according to claim 1, wherein the predetermined switching condition is satisfied when a predetermined time has elapsed since the start of the first heating control.

3. The power storage device is a battery pack configured by connecting a plurality of cells, the power storage system further includes a cell temperature sensor that detects the cell temperature of each of the plurality of cells included in the battery pack, and the predetermined switching condition is that the power storage device is being charged and the lowest cell temperature in the battery pack reaches a predetermined temperature or higher during execution of the first heating control. The vehicle according to claim 1, wherein the condition is satisfied. ​ ​ ​ ​ ​

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