Power System

Abstract

A power supply system is provided that can quickly ensure the power output performance of an energy storage device during cold starts. The power supply system includes: a capacity-type first battery; an output-type second battery with a smaller thermal capacity than the first battery; a voltage converter for converting voltage between a first power circuit and a second power circuit; a power converter for converting power between the first power circuit and a drive motor; and a power control means for operating the voltage converter and the power converter to control the charging and discharging of the first and second batteries. Upon startup, the power control means executes power path control for power transfer between the first and second batteries until the total output limit Ptot_max of all batteries (combining the first and second batteries) exceeds a drivable threshold Pready1. Then, it executes a second priority control that prioritizes the discharge of the second battery over the first battery until the first output limit P1_max of the first battery exceeds a margin drivability threshold Pready2.

Description

Technical Field

[0001] This invention relates to a power supply system. More specifically, it relates to a power supply system having two energy storage devices. Background Technology

[0002] In recent years, electric vehicles have flourished, including electric transportation equipment powered by a drive motor and hybrid vehicles powered by both a drive motor and an internal combustion engine. These electric vehicles also incorporate energy storage devices (batteries and capacitors, etc.) or fuel cells to supply power to the drive motor. Furthermore, in recent years, electric vehicles equipped with multiple power sources with different characteristics have also been developed.

[0003] Patent Document 1 discloses an invention relating to an electric vehicle that operates using electricity output from a first and a second energy storage device. For energy storage devices such as secondary batteries or capacitors, their power output performance decreases as the temperature drops. Therefore, when starting an electric vehicle in a low-temperature environment (a so-called cold start), it is necessary to heat up the energy storage devices until the power output performance required to operate the electric vehicle is ensured. The electric vehicle shown in Patent Document 1, during a cold start, transfers power between the first and second energy storage devices, utilizing the heat generated during charging and discharging to heat both devices.

[0004] [Existing technical documents]

[0005] [Patent Literature]

[0006] [Patent Document 1] Japanese Patent No. 4379441 Summary of the Invention

[0007] [The problem the invention aims to solve]

[0008] The electric vehicle shown in Patent Document 1, during cold start, performs power transfer between the first and second energy storage devices as described above until the desired driving performance (e.g., the level of driving performance with sufficient leeway described later) is ensured using these energy storage devices. Therefore, it is possible that time will be wasted before the vehicle can be driven.

[0009] The purpose of this invention is to provide a power supply system that can quickly ensure the power output performance of the energy storage device during cold start.

[0010] [Technical means to solve the problem]

[0011] (1) The power supply system of the present invention (e.g., power supply system 1 described below) includes: a first power circuit (e.g., first power circuit 2 described below) having a first energy storage device (e.g., first battery B1 described below); a second power circuit (e.g., second power circuit 3 described below) having a second energy storage device (e.g., second battery B2 described below) with a smaller heat capacity than the first energy storage device; a voltage converter (e.g., voltage converter 5 described below) for converting voltage between the first power circuit and the second power circuit; a power converter (e.g., power converter 43 described below) for converting power between the first power circuit and a rotary motor (e.g., drive motor M described below); and a power control means (e.g., electronic control unit described below). Unit (ECU) 71, motor ECU 72, and converter ECU 73) control the charging and discharging of the first and second energy storage devices by operating the voltage converter and the power converter; the power system is characterized in that: after startup, the power control means executes power path control for the transmission and reception of power between the first and second energy storage devices until a first condition related to the power output performance of either or both of the first and second energy storage devices (e.g., the first output limit P1_max, the second output limit P2_max, and the total output limit Ptot_max, described later) is met; then, a second priority control is executed to make the second energy storage device discharge more preferentially than the first energy storage device until a second condition related to the power output performance of either or both of the first and second energy storage devices is met.

[0012] (2) In this case, it is preferable that the second energy storage device has a higher output weight density and a lower energy weight density compared to the first energy storage device.

[0013] (3) The power supply system of the present invention (e.g., power supply system 1 described later) includes: a first power circuit (e.g., first power circuit 2 described later) having a first energy storage device (e.g., first battery B1 described later); a second power circuit (e.g., second power circuit 3 described later) having a second energy storage device (e.g., second battery B2 described later), the second energy storage device having a higher output weight density and a lower energy weight density than the first energy storage device; a voltage converter (e.g., voltage converter 5 described later) for converting voltage between the first power circuit and the second power circuit; a power converter (e.g., power converter 43 described later) for converting power between the first power circuit and a rotating motor (e.g., drive motor M described later); and a power control means (e.g., management ECU 71, motor ECU 72, and converter ECU 73 described later) for controlling the voltage converter and the power supply. The converter operates to control the charging and discharging of the first and second energy storage devices; the power system is characterized in that: after startup, the power control means executes power path control for transmitting and receiving power between the first and second energy storage devices until a first condition related to the power output performance of either or both of the first and second energy storage devices (e.g., the first output limit P1_max, the second output limit P2_max, and the total output limit Ptot_max, described later) is met; then, a second priority control is executed to make the second energy storage device discharge with higher priority than the first energy storage device until a second condition related to the power output performance of either or both of the first and second energy storage devices (e.g., the first output limit P1_max, the second output limit P2_max, and the total output limit Ptot_max, described later) is met.

[0014] (4) In this case, it is preferable that the heat capacity of the second energy storage device is less than that of the first energy storage device.

[0015] (5) In this case, preferably, the power supply system further includes a demand output acquisition means for obtaining the demand output of the rotating motor (e.g., the management ECU 71 and pedal type P described later), and the power control means, under the second priority control, operates the voltage converter and the power converter so that the demand output can be output from the first energy storage device minus the upper limit of the power that can be output from the second energy storage device, i.e., the second output upper limit, which is the insufficient portion.

[0016] (6) In this case, preferably, the second condition is that the upper limit of the power that can be output from the first energy storage device, i.e., the first output upper limit, exceeds the second condition threshold, and the power control means performs ordinary control to make the first energy storage device discharge more preferentially than the second energy storage device.

[0017] (7) In this case, it is preferable that the power control means, under the normal control, uses the power output from the first energy storage device to charge the second energy storage device.

[0018] (8) In this case, preferably, the power system further includes: a first cooling device (e.g., the first cooling device 91 described later) for cooling the first energy storage device; and a first cooling output control device (e.g., the management ECU 71 and cooling circuit ECU 76 described later) for controlling the first cooling output of the first cooling device; and the first cooling output control device makes the first cooling output smaller during the period before the second condition is met than after the second condition is met.

[0019] (9) In this case, preferably, the power system further includes: a second cooling device (e.g., the second cooling device 92 described later) for cooling the second energy storage device; and a second cooling output control device (e.g., the management ECU 71 and cooling circuit ECU 76 described later) for controlling the second cooling output of the second cooling device; and the second cooling output control device causes the second cooling output to be smaller during the period before the first condition is met than after the first condition is met.

[0020] [The effects of the invention]

[0021] (1) In this invention, after the power system is started, the power control means executes power path control for the transfer of power between the first and second energy storage devices, causing the first and second energy storage devices to heat up until a first condition related to the power output performance of either or both of the first and second energy storage devices is met. Then, the power control means executes a second priority control that prioritizes the discharge of the second energy storage device over the first energy storage device until a second condition related to power output performance is met. Here, in this invention, an energy storage device with a smaller heat capacity than the first energy storage device is used as the second energy storage device. Thus, according to this invention, by executing power path control and the second priority control during cold start, the second energy storage device can heat up more rapidly than the first energy storage device, and therefore, the necessary power output performance can be quickly ensured by primarily utilizing the second energy storage device.

[0022] (2) In this invention, an output-type energy storage device with a higher output weight density and a lower energy weight density than the first energy storage device is used as the second energy storage device. This allows the second energy storage device to heat up rapidly when performing power path control and second priority control. Therefore, the necessary power output performance can be ensured more quickly by mainly utilizing the second energy storage device.

[0023] (3) In this invention, an output-type energy storage device with a higher output weight density and a lower energy weight density than the first energy storage device is used as the second energy storage device. Therefore, according to this invention, by performing power path control and second priority control during cold start, the output-type second energy storage device can heat up more rapidly than the capacity-type first energy storage device. Thus, the necessary power output performance can be quickly ensured by mainly utilizing the second energy storage device.

[0024] (4) In this invention, an energy storage device with a smaller heat capacity than the first energy storage device is used as the second energy storage device. This allows the second energy storage device to heat up more quickly when performing power path control and second priority control. Therefore, the second energy storage device can be mainly used to ensure the necessary power output performance more quickly.

[0025] (5) In this invention, the power control means, under a second priority control, operates the voltage converter and the power converter so that the insufficient portion obtained by subtracting the upper limit of the power that can be output from the second energy storage device from the required output of the rotating motor from the first energy storage device, i.e., the second output upper limit, is obtained. Thus, after the first condition is met, by supplying the rotating motor with power corresponding to the required output from the first power circuit, the rotating motor can be driven while actively discharging from the second energy storage device, thereby enabling the second energy storage device to heat up rapidly.

[0026] (6) In this invention, the power control means, after executing the second priority control until the first output upper limit of the first energy storage device exceeds the second condition threshold, executes ordinary control that prioritizes the discharge of the second energy storage device (or, the output-type second energy storage device) with a smaller heat capacity than the first energy storage device. Therefore, after the second condition is met, the first energy storage device can be further heated, thus further improving the power output performance of the first energy storage device.

[0027] (7) In this invention, the power control means, under normal control after the second condition is met, uses the power output from the first energy storage device to charge the second energy storage device. As a result, sufficient reserve capacity can be ensured for the second energy storage device, which has become sufficiently high in terms of power output performance through power path control and second priority control, and the heating of the first energy storage device is promoted, thereby further increasing the power output performance of the first energy storage device.

[0028] (8) In this invention, the first cooling output control device makes the first cooling output of the first cooling device during the period before the second condition is met, i.e., the period during which the second energy storage device is mainly heated by power path control and second priority control, shorter than the period after the second condition is met. As a result, the time until the second condition is met can be shortened.

[0029] (9) In this invention, the second cooling output control device makes the second cooling output of the second cooling device that cools the second energy storage device, during the period before the first condition is met (i.e., the period during which the second energy storage device is heated by power path control), shorter than the period during which the second energy storage device is heated by executing the second priority control after the first condition is met. This shortens the time until the first condition is met, i.e., until power can be supplied to the rotating motor. Attached Figure Description

[0030] Figure 1 This is a diagram showing the structure of a vehicle equipped with a power supply system according to an embodiment of the present invention.

[0031] Figure 2 This is a diagram illustrating an example of the circuit structure of a voltage converter.

[0032] Figure 3 This is a diagram illustrating an example of the circuit structure of a cooling circuit.

[0033] Figure 4 It is a flowchart showing the specific procedures for power management.

[0034] Figure 5 It is a flowchart representing the specific procedure for cold start control.

[0035] Figure 6 It is a timing diagram showing the time changes of the first output limit, the second output limit, and the total output limit when cold start control is executed at startup. Detailed Implementation

[0036] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0037] Figure 1 This diagram illustrates the structure of a four-wheeled electric vehicle V (hereinafter simply referred to as "vehicle") equipped with the power system 1 of this embodiment. Furthermore, this embodiment describes the case where the power system 1 is mounted on the four-wheeled vehicle V, but the present invention is not limited thereto. Not limited to the four-wheeled vehicle V, the power system of the present invention can also be applied to mobile bodies that move using propulsion generated by a rotary motor, such as riding vehicles, ships, robots, and drones, or to stationary power sources.

[0038] The vehicle V includes: a drive wheel W; a drive motor M connected to the drive wheel W as a rotary motor; and a power system 1 that exchanges power between the drive motor M and the first battery B1 and the second battery B2 described below. Furthermore, this embodiment illustrates an example where the vehicle V primarily utilizes the power generated by the drive motor M for acceleration and deceleration, but the invention is not limited to this. The vehicle V may also be configured as a so-called hybrid vehicle, equipped with both a drive motor M and an engine as power sources.

[0039] A drive motor M is connected to a drive wheel W via a transmission mechanism (not shown). The torque generated by the drive motor M, supplied with three-phase AC power from the power supply system 1, is transmitted to the drive wheel W via the transmission mechanism (not shown), causing the drive wheel W to rotate and thus propelling the vehicle V. Furthermore, when the vehicle V decelerates, the drive motor M functions as a generator, producing regenerative power and applying a regenerative braking torque corresponding to the magnitude of this regenerative power to the drive wheel W. The regenerative power generated by the drive motor M appropriately charges batteries B1 and B2 in the power supply system 1.

[0040] The power system 1 includes: a first power circuit 2 connected to a first battery B1; a second power circuit 3 connected to a second battery B2; a voltage converter 5 connecting the first power circuit 2 and the second power circuit 3; a load circuit 4 having various electrical loads including a drive motor M; a cooling circuit 9 for cooling the first battery B1 or the second battery B2; and an electronic control unit group 7 that controls the flow of power in the power circuits 2, 3, and 4, the charging and discharging of batteries B1 and B2, and the cooling output of the cooling circuit 9 by operating the power circuits 2, 3, and 4, the cooling circuit 9, and the voltage converter 5. Each of the electronic control unit groups 7 includes a computer (i.e., management ECU 71), a motor ECU 72, a converter ECU 73, a first battery ECU 74, a second battery ECU 75, and a cooling circuit ECU 76.

[0041] The first battery B1 is a secondary battery capable of both discharging and charging. Discharging refers to converting chemical energy into electrical energy, and charging refers to converting electrical energy into chemical energy. Hereinafter, a case is described where a so-called lithium-ion battery is used as the first battery B1, but the present invention is not limited thereto. The so-called lithium-ion battery utilizes the movement of lithium ions between electrodes to perform charging and discharging.

[0042] A first battery sensor unit 81 is provided for the first battery B1, which is used to infer the internal state of the first battery B1. The first battery sensor unit 81 is composed of multiple sensors that detect physical quantities such as the charge rate (expressed as a percentage of battery capacity) or temperature required to obtain the remaining amount of the first battery B1 in the first battery ECU 74, and send signals corresponding to the detected values ​​to the first battery ECU 74. More specifically, the first battery sensor unit 81 is composed of a voltage sensor for detecting the terminal voltage of the first battery B1, a current sensor for detecting the current flowing through the first battery B1, and a temperature sensor for detecting the temperature of the first battery B1.

[0043] The second battery B2 is a rechargeable battery capable of both discharging and charging. Discharging refers to the conversion of chemical energy into electrical energy, and charging refers to the conversion of electrical energy into chemical energy. Hereinafter, a case is described using a so-called lithium-ion battery as the second battery B2, but the present invention is not limited thereto. The so-called lithium-ion battery utilizes the movement of lithium ions between electrodes for charging and discharging. For example, a capacitor may also be used as the second battery B2.

[0044] A second battery sensor unit 82 is provided for the second battery B2, which is used to infer the internal state of the second battery B2. The second battery sensor unit 82 is composed of multiple sensors that detect physical quantities required to obtain the corresponding charge rate or temperature of the second battery B2 in the second battery ECU 75, and send signals corresponding to the detected values ​​to the second battery ECU 75. More specifically, the second battery sensor unit 82 is composed of a voltage sensor for detecting the terminal voltage of the second battery B2, a current sensor for detecting the current flowing through the second battery B2, and a temperature sensor for detecting the temperature of the second battery B2.

[0045] Here, the characteristics of the first battery B1 are compared with those of the second battery B2.

[0046] Compared to the second battery B2, the first battery B1 has a lower output weight density and a higher energy weight density. Furthermore, the discharge capacity of the first battery B1 is greater than that of the second battery B2. That is, in terms of energy weight density, the first battery B1 is superior to the second battery B2. Moreover, energy weight density refers to electricity per unit weight [Wh / kg], while output weight density is electricity per unit weight [W / kg]. Therefore, the first battery B1, with its superior energy weight density, is a capacity-type energy storage device primarily designed for high capacity, while the second battery B2, with its superior output weight density, is an output-type energy storage device primarily designed for high output. Therefore, in power system 1, the first battery B1 is used as the main power source, and the second battery B2 is used as a supplementary power source to supplement the first battery B1. Additionally, the thermal capacity of the second battery B2 is less than that of the first battery B1. Therefore, the second battery B2 heats up more rapidly than the first battery B1.

[0047] The first power circuit 2 includes: a first battery B1; first power lines 21p and 21n, connecting the positive and negative terminals of the first battery B1 to the positive and negative terminals of the high-voltage side of the voltage converter 5; and a positive contactor 22p and a negative contactor 22n, disposed on the first power lines 21p and 21n.

[0048] Contactors 22p and 22n are normally open contactors. They open when no external command signal is input, thereby cutting off the conduction between the two electrodes of the first battery B1 and the first power lines 21p and 21n. They close when a command signal is input, thereby connecting the first battery B1 and the first power lines 21p and 21n. The contactors 22p and 22n open and close according to the command signal sent from the first battery ECU 74. Furthermore, the positive contactor 22p is a pre-charge contactor with a pre-charge resistor, which is used to mitigate the inrush current flowing to the multiple smoothing capacitors disposed in the first power circuit 2 or load circuit 4, etc.

[0049] The second power circuit 3 includes: a second battery B2; second power lines 31p and 31n, connecting the positive and negative terminals of the second battery B2 to the positive and negative terminals of the low-voltage side of the voltage converter 5; a positive contactor 32p and a negative contactor 32n, disposed on the second power lines 31p and 31n; and a current sensor 33, disposed on the second power line 31p.

[0050] Contactors 32p and 32n are normally open contactors. They open when no external command signal is input, thereby cutting off the conduction between the two electrodes of the second battery B2 and the second power lines 31p and 31n. They close when a command signal is input, thereby connecting the second battery B2 and the second power lines 31p and 31n. The contactors 32p and 32n open and close according to the command signal sent from the second battery ECU 75. Furthermore, the positive contactor 32p is a pre-charge contactor with a pre-charge resistor, which is used to mitigate the inrush current flowing to the multiple smoothing capacitors disposed in the first power circuit 2 or the load circuit 4, etc.

[0051] The current sensor 33 sends a detection signal corresponding to the current flowing through the converter ECU 73. This current is the current flowing through the second power line 31p, i.e., the current flowing through the voltage converter 5. Furthermore, in this embodiment, the direction of the current flowing through the converter is defined as positive from the second power circuit 3 side towards the first power circuit 2 side, and negative from the first power circuit 2 side towards the second power circuit 3 side. That is, the current flowing through the voltage converter 5 becomes positive when the second battery B2 is discharging and negative when the second battery B2 is charging.

[0052] The load circuit 4 includes: a vehicle auxiliary machine 42; a power converter 43 connected to a drive motor M; and load power lines 41p and 41n connecting the vehicle auxiliary machine 42 and the power converter 43 to the first power circuit 2.

[0053] The vehicle auxiliary unit 42 consists of multiple electrical loads, including a battery heater, an air compressor, a DC-DC converter, and an on-board charger. The vehicle auxiliary unit 42 is connected to the first power lines 21p and 21n of the first power circuit 2 via load power lines 41p and 41n, and operates by consuming power from the first power lines 21p and 21n. Information related to the operating status of the various electrical loads constituting the vehicle auxiliary unit 42 is sent, for example, to the management ECU 71.

[0054] The power converter 43 is connected to the first power lines 21p and 21n in parallel with the vehicle auxiliary equipment 42 via load power lines 41p and 41n. The power converter 43 converts power between the first power lines 21p and 21n and the drive motor M. The power converter 43 is, for example, a pulse width modulation (PWM) inverter that includes a bridging circuit comprising multiple switching elements (e.g., insulated-gate bipolar transistors, IGBTs) and utilizes pulse width modulation, and has the function of converting DC power to AC power. The power converter 43 is connected to the first power lines 21p and 21n on its DC input / output side, and to the coils of the U-phase, V-phase, and W-phase of the drive motor M on its AC input / output side. The power converter 43 drives the switching elements of each phase to turn on / off according to the gate drive signal generated from the gate drive circuit (not shown) of the motor ECU 72 at a predetermined time, thereby converting the DC power in the first power lines 21p and 21n into three-phase AC power and supplying it to the drive motor M, or converting the three-phase AC power supplied from the drive motor M into DC power and supplying it to the first power lines 21p and 21n.

[0055] Voltage converter 5 connects the first power circuit 2 and the second power circuit 3, and transforms the voltage between the two circuits 2 and 3. A known boost circuit is used in this voltage converter 5.

[0056] Figure 2 This diagram illustrates an example of the circuit structure of voltage converter 5. Voltage converter 5 connects the first power lines 21p and 21n connected to the first battery B1 and the second power lines 31p and 31n connected to the second battery B2, and transforms the voltage between the first power lines 21p and 21n and the second power lines 31p and 31n. Voltage converter 5 is a full-bridge DC-DC converter, constructed by combining a first reactor L1, a second reactor L2, a first high-arm element 53H, a first low-arm element 53L, a second high-arm element 54H, a second low-arm element 54L, a negative bus 55, low-voltage side terminals 56p and 56n, high-voltage side terminals 57p and 57n, and a smoothing capacitor (not shown).

[0057] Low-voltage side terminals 56p and 56n are connected to the second power lines 31p and 31n, and high-voltage side terminals 57p and 57n are connected to the first power lines 21p and 21n. Negative busbar 55 is the wiring connecting low-voltage side terminal 56n and high-voltage side terminal 57n.

[0058] One end of the first reactor L1 is connected to the low-voltage side terminal 56p, and the other end is connected to the connection node 53 between the first high-arm element 53H and the first low-arm element 53L. The first high-arm element 53H and the first low-arm element 53L each include a known power switching element such as an IGBT or a Metal Oxide Semiconductor Field Effect Transistor (MOSFET), and a return-current diode connected to the power switching element. The high-arm element 53H and the low-arm element 53L are connected in series between the high-voltage side terminal 57p and the negative bus 55.

[0059] The collector of the power switching element in the first high-arm element 53H is connected to the high-voltage side terminal 57p, and the emitter is connected to the collector of the first low-arm element 53L. The emitter of the power switching element in the first low-arm element 53L is connected to the negative bus 55. The return diode on the first high-arm element 53H is oriented from the first reactor L1 toward the high-voltage side terminal 57p. Similarly, the return diode on the first low-arm element 53L is oriented from the negative bus 55 toward the first reactor L1.

[0060] One end of the second reactor L2 is connected to the low-voltage side terminal 56p, and the other end is connected to the connection node 54 between the second high-arm element 54H and the second low-arm element 54L. The second high-arm element 54H and the second low-arm element 54L each include a known power switching element such as an IGBT or MOSFET, and a return diode connected to the power switching element. The high-arm element 54H and the low-arm element 54L are connected in series between the high-voltage side terminal 57p and the negative bus 55.

[0061] The collector of the power switching element of the second high-arm element 54H is connected to the high-voltage side terminal 57p, and the emitter is connected to the collector of the second low-arm element 54L. The emitter of the power switching element of the second low-arm element 54L is connected to the negative bus 55. The return diode provided on the second high-arm element 54H is oriented from the second reactor L2 toward the high-voltage side terminal 57p. Similarly, the return diode provided on the second low-arm element 54L is oriented from the negative bus 55 toward the second reactor L2.

[0062] The voltage converter 5 alternately turns on / off the first high arm element 53H and the second low arm element 54L, and the first low arm element 53L and the second high arm element 54H, according to the gate drive signal generated from the gate drive circuit (not shown) of the converter ECU73 at a predetermined time, thereby changing the voltage between the first power lines 21p, 21n and the second power lines 31p, 31n.

[0063] The static voltage of the second battery B2 is maintained at a level lower than that of the first battery B1. Therefore, the voltage of the first power lines 21p and 21n is generally higher than that of the second power lines 31p and 31n. Thus, when the drive motor M is driven using both the power output from the first battery B1 and the power output from the second battery B2, the converter ECU 73 operates the voltage converter 5 to perform a boost function. The boost function refers to boosting the power in the second power lines 31p and 31n connected to the low-voltage side terminals 56p and 56n and outputting it to the first power lines 21p and 21n connected to the high-voltage side terminals 57p and 57n, thereby allowing positive current to flow from the second power lines 31p and 31n side to the first power lines 21p and 21n side. In addition, while suppressing the discharge of the second battery B2 and using only the power output from the first battery B1 to drive the drive motor M, the converter ECU73 disconnects the voltage converter 5 so that current does not flow from the first power lines 21p, 21n to the second power lines 31p, 31n.

[0064] Additionally, during deceleration, the regenerative power output from the drive motor M to the first power lines 21p and 21n is used to charge either the first battery B1 or the second battery B2. In this case, the converter ECU 73 operates the voltage converter 5 to enable it to perform a step-down function. The step-down function refers to the function of reducing the voltage in the first power lines 21p and 21n connected to the high-voltage side terminals 57p and 57n and outputting it to the second power lines 31p and 31n connected to the low-voltage side terminals 56p and 56n. This causes a negative current to flow from the first power lines 21p and 21n side to the second power lines 31p and 31n side.

[0065] As described above, in the power supply system 1, the voltage converter 5 and the power converter 43 are operated using the management ECU 71, the motor ECU 72, and the converter ECU 73 to control the power flowing through the voltage converter 5 or the power converter 43, thereby controlling the charging and discharging of the first battery B1 and the second battery B2. Therefore, in this embodiment, the power control means for controlling the charging and discharging of the first battery B1 and the second battery B2 is composed of the management ECU 71, the motor ECU 72, and the converter ECU 73.

[0066] Return to Figure 1 The first battery ECU 74 is a computer primarily responsible for monitoring the state of the first battery B1 and controlling the opening and closing of contactors 22p and 22n in the first power circuit 2. Based on a known algorithm using detection values ​​sent from the first battery sensor unit 81, the first battery ECU 74 calculates various parameters representing the internal state of the first battery B1. More specifically, it calculates the temperature of the first battery B1, its internal resistance, its static voltage, its closed-circuit voltage, a first output limit corresponding to the upper limit of the power that can be output from the first battery B1, and a first state of charge (SOC) corresponding to the charging rate of the first battery B1. Information related to the parameters representing the internal state of the first battery B1 obtained by the first battery ECU 74 is, for example, sent to the management ECU 71.

[0067] The second battery ECU 75 is a computer primarily responsible for monitoring the state of the second battery B2 and controlling the opening and closing of contactors 32p and 32n in the second power circuit 3. Based on known algorithms using detection values ​​sent from the second battery sensor unit 82, the second battery ECU 75 calculates various parameters representing the internal state of the second battery B2. More specifically, it calculates the temperature of the second battery B2, its internal resistance, its static voltage, its closed-circuit voltage, a second output limit corresponding to the upper limit of the power that can be output from the second battery B2, and a second state of charge (SOC) corresponding to the charging rate of the second battery B2. Information related to the parameters representing the internal state of the second battery B2 obtained by the second battery ECU 75 is, for example, sent to the management ECU 71.

[0068] The management ECU 71 is a computer primarily responsible for managing the flow of power throughout the entire power system 1. The management ECU 71 utilizes the reference after execution... Figure 4 The power management process generates a torque command signal and a converter power command signal. The torque command signal is equivalent to a command for the torque generated by the drive motor M, and the converter power command signal is equivalent to a command for the power supplied through the voltage converter 5.

[0069] The motor ECU 72 is a computer that primarily operates the power converter 43, controlling the flow of power between the first power circuit 2 and the drive motor M, specifically the flow of power through the inverter via the power converter 43. Furthermore, when power flows from the first power circuit 2 to the drive motor M, i.e., when the drive motor M is accelerating, the inverter power supply is set to positive. Conversely, when power flows from the drive motor M to the first power circuit 2, i.e., when the drive motor M is regenerating, the inverter power supply is set to negative. The motor ECU 72 operates the power converter 43 based on a torque command signal calculated according to the command for inverter power supply in the management ECU 71, causing the drive motor M to generate torque corresponding to that command.

[0070] The converter ECU 73 is a computer that primarily operates the voltage converter 5, controlling the flow of power between the first power circuit 2 and the second power circuit 3, that is, controlling the flow of power through the converter of power passing through the voltage converter 5. Furthermore, when power flows from the second power circuit 3 to the first power circuit 2, i.e., when power is released from the second battery B2 and supplied to the first power circuit 2, the converter's power supply is set to positive. Conversely, when power flows from the first power circuit 2 to the second power circuit 3, i.e., when the second battery B2 is charged using power from the first power circuit 2, the converter's power supply is set to negative. The converter ECU 73 operates the voltage converter 5 according to the converter power supply command signal sent from the management ECU 71, causing the converter power supply corresponding to the command to pass through the voltage converter 5. More specifically, the converter ECU73 calculates the target current as the target for the through current in the voltage converter 5 based on the power command signal of the converter, and operates the voltage converter 5 according to a known feedback control algorithm so that the through current (hereinafter also referred to as "actual through current") detected by the current sensor 33 reaches the target current.

[0071] Figure 3 This is a diagram showing the circuit structure of cooling circuit 9.

[0072] The cooling circuit 9 includes: a first cooling device 91 for cooling the first battery B1, a second cooling device 92 for cooling the second battery B2, and a third cooling device 93 for cooling the voltage converter 5 and the power converter 43.

[0073] The first cooling device 91 includes: a first cooling water circulation path 911, which includes a cooling water flow path formed on the battery case containing the first battery B1; a first heat exchanger 912 and a first cooling water pump 913, which are disposed on the first cooling water circulation path 911; and a heating device 94, which is connected to the first cooling water circulation path 911.

[0074] A first cooling water pump 913 rotates according to a command input from the cooling circuit ECU 76, causing cooling water to circulate within a first cooling water circulation path 911. A first heat exchanger 912 facilitates heat exchange between the cooling water circulating within the first cooling water circulation path 911 and external air, thereby cooling the cooling water that has heated up due to heat exchange with the first battery B1. The first heat exchanger 912 includes a cooling fan that rotates according to a command input from the cooling circuit ECU 76.

[0075] The heating device 94 includes: a bypass path 941 that connects the inlet and outlet of the first heat exchanger 912 in the first cooling water circulation path 911 and bypasses the first heat exchanger 912; a heater 942 and a heating pump 943 disposed in the bypass path 941; and three-way valves 944 and 945 disposed at the connection points between the two ends of the bypass path 941 and the first cooling water circulation path 911.

[0076] The heating pump 943 rotates according to the command input from the cooling circuit ECU 76, causing the cooling water to circulate in the first cooling water circulation path 911 and the bypass path 941. The heater 942 consumes power supplied by a battery (not shown) to generate heat, thereby raising the temperature of the cooling water flowing through the bypass path 941.

[0077] Three-way valves 944 and 945 open and close according to commands from the cooling circuit ECU 76, switching the flow path of cooling water between the first heat exchanger 912 side and the heater 942 side. Therefore, the first cooling device 91 has both cooling and heating functions. The cooling function refers to cooling the first battery B1 by circulating cooling water cooled by the first heat exchanger 912, and the heating function refers to heating the first battery B1 by circulating cooling water heated by the heater 942. The cooling circuit ECU 76 operates the first heat exchanger 912, the first cooling water pump 913, the heater 942, the heating pump 943, and the three-way valves 944 and 945 based on the detection value of a cooling water temperature sensor (not shown) or commands from the management ECU 71, thereby controlling a first cooling output equivalent to the cooling performance of the first cooling device 91 for the first battery B1. Therefore, in this embodiment, the first cooling output control device controlling the first cooling output of the first cooling device 91 consists of the management ECU 71 and the cooling circuit ECU 76.

[0078] The second cooling device 92 is, for example, a cooling fan that supplies external gas to the battery case housing the second battery B2. The second cooling device 92 rotates according to instructions from the cooling circuit ECU 76, supplying external gas to the battery case of the second battery B2, thereby cooling the second battery B2.

[0079] The third cooling device 93 includes: a third cooling water circulation path 931, which includes a cooling water flow path formed on a frame on which the voltage converter 5 and the power converter 43 are provided; and a third heat exchanger 932 and a third cooling water pump 933, which are provided on the third cooling water circulation path 931.

[0080] The third cooling water pump 933 rotates according to commands input from the cooling circuit ECU 76, causing cooling water to circulate within the third cooling water circulation path 931. The third heat exchanger 932 facilitates heat exchange between the cooling water circulating within the third cooling water circulation path 931 and the external air, thereby cooling the cooling water that has been heated due to heat exchange with the voltage converter 5 and the power converter 43. The third heat exchanger 932 includes a cooling fan that rotates according to commands input from the cooling circuit ECU 76.

[0081] The cooling circuit ECU 76 operates the third heat exchanger 932 and the third cooling water pump 933 based on the detection value of the cooling water temperature sensor (not shown) or the command from the management ECU 71, thereby controlling a third cooling output with cooling performance equivalent to that of the third cooling device 93 for the voltage converter 5 or the power converter 43.

[0082] As described above, in this embodiment, the first cooling device 91 for cooling the first battery B1 and the third cooling device 93 for cooling the voltage converter 5, etc., are water-cooled and cooled by heat exchange with cooling water. The second cooling device 92 for cooling the second battery B2, which has a smaller heat capacity than the first battery B1, is air-cooled and cooled by heat exchange with external gas. However, the present invention is not limited to this. The first cooling device 91 may be air-cooled, the second cooling device 92 water-cooled, and the third cooling device 93 air-cooled. Furthermore, in this embodiment, the circulation path of the cooling water used to cool the first battery B1 and the circulation path of the cooling water used to cool the voltage converter 5 or the power converter 43 are different systems. However, the present invention is not limited to this. Either the voltage converter 5 or the power converter 43, or any one of them, may also be cooled using the same cooling water used to cool the first battery B1.

[0083] Figure 4 This is a flowchart illustrating the specific procedures of the power management process. This power management process, from the driver turning on the start switch (not shown) to start the vehicle V and the power system 1, to the driver turning off the start switch again to stop the vehicle V and the power system 1, is repeatedly executed in the management ECU 71 at a predetermined cycle.

[0084] First, in step S1, the management ECU 71 obtains the upper limit of the power output from the first battery B1 (i.e., the first output limit P1_max) and the upper limit of the power output from the second battery B2 (i.e., the second output limit P2_max) from the first battery ECU 74 and the second battery ECU 75 respectively as parameters representing the current power output performance of the first battery B1 and the second battery B2, and then proceeds to step S2.

[0085] Secondly, in step S2, the management ECU 71 determines whether the first output upper limit P1_max obtained in step S1 is greater than the margin driving threshold Pready2 (P1_max > Pready2) which is set as the second condition threshold. Furthermore, the margin driving threshold Pready2 is, for example, equivalent to the power available for margin driving, and more specifically, equivalent to the power available for high-speed driving that can be performed using the driving force generated by the drive motor M without full power.

[0086] If the determination result in step S2 is YES, that is, if the first battery B1 is heated to the point where it can be driven with sufficient power output from the first battery B1 and the power output performance of the first battery B1 is ensured, then proceed to step S3.

[0087] In step S3, the management ECU 71 calculates the target converter power Pcnv_cmd corresponding to the target power target for the converter in voltage converter 5 and the target inverter power Pmot_cmd corresponding to the target power target for the inverter in power converter 43 by performing normal control that prioritizes the discharge of the first battery B1 over the second battery B2, and then proceeds to step S5.

[0088] Here, under normal control, the ECU 71 is managed to essentially ensure that the inverter in the power converter 43 receives power Pmot_d (refer to the following description) in accordance with the power demand of the drive motor M. Figure 5 In step S15, the target converter power supply Pcnv_cmd and the target inverter power supply Pmot_cmd are calculated entirely from the power output from the first battery B1. Furthermore, if the aforementioned inverter power supply Pmot_d exceeds the first output limit P1_max of the first battery B1, the management ECU 71 calculates the target converter power supply Pcnv_cmd and the target inverter power supply Pmot_cmd by subtracting the first output limit P1_max from the demand inverter power supply Pmot_d from the second battery B2. Additionally, under normal control, the management ECU 71 appropriately charges the second battery B2 using the power output from the first battery B1, ensuring that the second SOC of the second battery B2 is appropriately obtained from the second battery ECU 75 and maintained within a predetermined second SOC target range. That is, when the second SOC is lower than the lower limit of the second SOC target range, the management ECU71 sets the target converter to a negative value via power Pcnv_cmd, thereby using the power output from the first battery B1 to charge the second battery B2.

[0089] Furthermore, if the determination result in step S2 is negative (NO), that is, if the first battery B1 has not been heated to a level where it can be driven comfortably using only the power output from the first battery B1, the process proceeds to step S4. In step S4, the process is referenced after execution. Figure 5 The cold start control is described, which calculates the power supply Pcnv_cmd of the target converter and the power supply Pmot_cmd of the target inverter, and then proceeds to step S5.

[0090] Next, in step S5, the management ECU 71 generates a converter power command signal corresponding to the target converter power Pcnv_cmd and sends the converter power command signal to the converter ECU 73, then proceeds to step S6. Thus, power corresponding to the target converter power Pcnv_cmd is charged or released from the second battery B2.

[0091] Next, in step S6, the management ECU 71 generates a torque command signal based on the power Pmot_cmd transmitted by the target inverter and sends this torque command signal to the motor ECU 72, then ends the power management process. More specifically, the management ECU 71 calculates the target drive torque by converting the power Pmot_cmd transmitted by the target inverter into torque, and generates a torque command signal corresponding to the target drive torque. The motor ECU 72 operates the power converter 43 based on this torque command signal. Thus, the power corresponding to the power Pmot_cmd transmitted by the target inverter flows between the first power circuit 2 and the drive motor M.

[0092] Figure 5 It is a flowchart representing the specific procedure for cold start control.

[0093] First, in step S11, the management ECU71 adds the first output upper limit P1_max obtained in step S1 to the second output upper limit P2_max, thereby calculating the total output upper limit Ptot_max, which is equivalent to the upper limit of the power that can be output from all batteries, as a parameter representing the power output performance of all batteries that combine the first battery B1 and the second battery B2, and then proceeds to step S12.

[0094] Secondly, in step S12, the management ECU 71 determines whether the total output upper limit Ptot_max calculated in step S11 is greater than the drivable threshold Pready1 (Ptot_max > Pready1), which is set as the first condition threshold. This drivable threshold Pready1 is set to a value smaller than the aforementioned margin drivability threshold Pready2. More specifically, this drivable threshold Pready1 is, for example, equivalent to the lower limit of the electric power available for urban driving using the driving force generated by the drive motor M.

[0095] If the determination result in step S12 is negative, that is, if it is not ensured that the power output performance of the first battery B1 and the second battery B2 is sufficient to drive in the city using the power output from all the batteries, the process proceeds to step S13.

[0096] In step S13, the management ECU71 sets the target inverter to 0 via power Pmot_cmd to prevent vehicle V from driving, and then proceeds to step S14.

[0097] Secondly, in step S14, the management ECU71, using power path control that performs power transfer between the first battery B1 and the second battery B2, calculates the target converter's power Pcnv_cmd and then transfers it to... Figure 4 Step S5. Under this power path control, the management ECU 71 first obtains the first SOC and the second SOC from the battery ECUs 74 and 75, and determines the discharge battery and the recharge battery based on the first SOC and the second SOC. The management ECU 71 essentially designates the battery with the higher SOC among batteries B1 and B2 as the discharge battery, and the battery with the lower SOC among batteries B1 and B2 as the recharge battery. Furthermore, the management ECU 71 calculates the target converter power Pcnv_cmd within the upper limit of the discharge battery's output, by transferring power from the discharge battery to the recharge battery via the voltage converter 5. For example, when the first battery B1 is designated as the discharge battery and the second battery B2 as the recharge battery, the management ECU 71 calculates the target converter power Pcnv_cmd within the range of 0 to -P1_max. Similarly, when the second battery B2 is designated as the discharge battery and the first battery B1 is designated as the recharge battery, the management ECU 71 calculates the target converter power Pcnv_cmd within the range of 0 to P2_max. Therefore, under power path control, power is supplied from the discharge battery to the rechargeable battery via voltage converter 5, and the discharge battery and rechargeable battery are heated. In addition, when the SOC of the discharge battery is lower than a specified lower limit or the SOC of the rechargeable battery exceeds a specified upper limit, the management ECU 71 sets the current discharge battery as the rechargeable battery and the current rechargeable battery as the discharge battery, thereby executing power path control until the condition of step S12 (Ptot_max > Pready1) is met, causing the first battery B1 and the second battery B2 to heat up.

[0098] Additionally, if the determination result in step S12 is yes, that is, if the power output performance of the first battery B1 and the second battery B2 is ensured to the extent that the power output from all batteries can be used for driving in urban areas, the process proceeds to step S15.

[0099] In step S15, the management ECU 71, based on the driver's use of pedals such as the accelerator pedal or brake pedal (see...), performs a process that... Figure 1 The system calculates the required driving torque for the driver by adjusting the amount of power input, and converts this required driving torque into electricity. Then, it calculates the required output of the inverter corresponding to the required output of the drive motor M, and then proceeds to step S16.

[0100] Secondly, in step S16, the management ECU71 determines whether the power demand Pmot_d calculated in step S15 is below the total output limit Ptot_max calculated in step S11.

[0101] If the determination result in step S16 is yes, the management ECU 71 proceeds to step S17, sets the power supply Pmot_d of the demand inverter to the power supply Pmot_cmd of the target inverter, and then proceeds to step S19 (Pmot_cmd = Pmot_d). Alternatively, if the determination result in step S16 is no, the management ECU 71 proceeds to step S18, sets the total output limit Ptot_max to the power supply Pmot_cmd of the target inverter, and then proceeds to step S19 (Pmot_cmd = Ptot_max). As described above, after satisfying the conditions of step S12, the management ECU 71 sets the power supply Pmot_cmd of the target inverter within the range of 0 to the total output limit Ptot_max to allow driving.

[0102] In step S19, the management ECU 71 executes a second priority control that prioritizes the charging and discharging of the second battery B2 over the first battery B1, thereby calculating the target converter via power Pcnv_cmd, and then transferring to... Figure 4 Step S5.

[0103] Here, under the second priority control, the management ECU 71 calculates the target converter's power Pcnv_cmd in a manner that essentially ensures the target inverter's power Pmot_cmd is entirely supplied by the power output from the second battery B2. Furthermore, if the target inverter's power Pmot_cmd exceeds the second output limit P2_max of the second battery B2, the management ECU 71 calculates the target converter's power Pcnv_cmd by subtracting the insufficient portion obtained from the second output limit P2_max from the first battery B1. As described above, after satisfying the conditions of step S12, the management ECU 71 executes the second priority control, which focuses on raising the temperature of the second battery B2 by actively charging and discharging it, until the conditions are met. Figure 4 Until the conditions of step S2 are met.

[0104] Figure 6 This is a timing diagram showing the time changes of the first output limit P1_max, the second output limit P2_max, the total output limit Ptot_max, the first cooling output, and the second cooling output when the vehicle V and the power system 1 are started and the cold start control described above is executed.

[0105] First, at time t0, the driver starts the vehicle V and the power system 1. Because the first battery B1 and the second battery B2 have been completely cooled down due to prolonged exposure to low temperatures, therefore... Figure 6 The statement indicates the case where the first output limit P1_max at time t0 is insufficient to meet the margin driving threshold Pready2, and the total output limit Ptot_max is also insufficient to meet the drivable threshold Pready1 (refer to...). Figure 4 Step S2 and Figure 5 Step S12). Therefore, after starting at time t0, the ECU 71 is controlled to prevent vehicle V from driving (refer to step S12). Figure 5 Step S13), and perform power path control for power transmission and reception between the first battery B1 and the second battery B2 (see step S13). Figure 5 Step S14), until the condition is met. Figure 5 The conditions for step S12 are met. Therefore, after time t0, the first battery B1 and the second battery B2 gradually heat up, and the first output upper limit P1_max and the second output upper limit P2_max increase. Furthermore, at this time, because the heat capacity of the second battery B2 is less than that of the first battery B1, the temperature of the second battery B2 will rise more rapidly than the temperature of the first battery B1, and the second output upper limit P2_max will also rise more rapidly than the first output upper limit P1_max.

[0106] Then, at time t1, the total output limit Ptot_max exceeds the drivable threshold Pready1. That is, at time t1, the following condition is met. Figure 5 The conditions for step S12. Therefore, the management ECU 71 sets the vehicle V to a drivable state (see step S12). Figure 5 Steps S15 to S18), and a second priority control is executed to give priority to charging and discharging of the first battery B1 over the second battery B2 (see step S15 to S18). Figure 5 Step S19), until the condition is met. Figure 4 The condition for step S2 is met. Therefore, after time t1, the second output limit P2_max increases further because the second battery B2 heats up more aggressively.

[0107] Then, at time t2, the total output limit Ptot_max exceeds the margin driving threshold Pready2. Therefore, although vehicle V does not meet the condition at time t2... Figure 4 The conditions of step S2 are met, but the output of all batteries combined with the first battery B1 and the second battery B2 can be used to enable leeway driving.

[0108] Then, at time t3, the first output upper limit P1_max exceeds the margin driving threshold Pready2. That is, at time t3, the following condition is met. Figure 4The conditions for step S2. Therefore, the management ECU 71 executes the normal control that prioritizes the discharge of the first battery B1 over the second battery B2 (see reference). Figure 4 Step S3).

[0109] As described above, in order to enable the vehicle V to drive quickly and with sufficient driving capacity during a cold start, the power system 1 needs to rapidly heat up the second battery B2 under power path control during time t0 to time t1 and under second priority control after time t1. Therefore, the cooling circuit ECU 76 preferably starts at time t0 and continues until the desired conditions are met at time t1. Figure 5 During the period up to the condition in step S12, the second cooling output of the second cooling device 92 is set to low, and after time t1, the second cooling output is set to normal. That is, the cooling circuit ECU 76, preferably after starting at time t0, remains set to normal until the condition is met at time t1. Figure 5 During the period up to the condition in step S12, the second cooling output is made smaller than the second cooling output after time t1. Furthermore, the cooling circuit ECU76 will raise the first output upper limit P1_max to the margin driving threshold Pready2 as quickly as possible; therefore, it is preferable to raise it from startup at time t0 until the condition is met at time t2. Figure 4 During the period up to step S2, the first cooling output of the first cooling device 91 is set to low, and after time t2, the first cooling output is set to normal. That is, the cooling circuit ECU 76, preferably after starting at time t0, remains set to normal until the condition is met at time t2. Figure 4 During the period up to the condition of step S2, the first cooling output of the first cooling device 91 is smaller than the first cooling output after time t2.

[0110] According to the power supply system 1 of this embodiment, the following effects are produced.

[0111] (1) The ECU71, after the vehicle V starts, performs power path control between the first battery B1 and the second battery B2, causing the batteries B1 and B2 to heat up until the first condition related to the total output limit Ptot_max of all batteries combining the first battery B1 and the second battery B2 is met. Figure 5 Step S12) is then executed. Then, the ECU 71 is managed to perform a second priority control that prioritizes the discharge of the second battery B2 over the first battery B1, until a second condition related to the first output limit P1_max of the first battery B1 is met. Figure 4Up to step S2). Here, in power system 1, a battery with a smaller thermal capacity than the first battery B1 is used as the second battery B2. Thus, according to power system 1, by performing power path control and second priority control during cold start, the second battery B2 can be heated up more rapidly than the first battery B1, and therefore, the necessary power output performance can be quickly ensured by mainly utilizing the second battery B2.

[0112] (2) In the power supply system 1, an output type battery with a smaller heat capacity than the first battery B1, a higher output weight density than the first battery B1, and a lower energy weight density than the first battery B1 is used as the second battery B2. This allows the second battery B2 to heat up more quickly when performing power path control and second priority control. Therefore, the second battery B2 can be mainly used to ensure the necessary power output performance more quickly.

[0113] (3) In power supply system 1, an output-type battery with a higher output weight density and a lower energy weight density than the first battery B1 is used as the second battery B2. Therefore, according to power supply system 1, by performing power path control and second priority control during cold start, the output-type second battery B2 can be heated up more rapidly than the capacity-type first battery B1. Thus, the necessary power output performance can be quickly ensured by mainly utilizing the second battery B2.

[0114] (4) The ECU 71, under the second priority control, operates the voltage converter 5 and the power converter 43 so that the demand inverter, which outputs power from the first battery B1 to the demand output in the drive motor M, can subtract the second output limit P2_max from the power Pmot_d to obtain the insufficient portion. Thus, after the first condition is met, by supplying the demand-corresponding power from the first power circuit 2 to the drive motor M, it is possible to generate propulsion force to move the vehicle V while actively discharging from the second battery B2, thereby enabling the second battery B2 to heat up rapidly.

[0115] (5) The ECU 71, after executing the second priority control, executes normal control to prioritize the discharge of the second battery B2, which has a smaller heat capacity than the first battery B1, until the first output limit P1_max of the first battery B1 exceeds the margin driving threshold Pready2. This allows the first battery B1 to be further heated after the second condition is met, thus further improving the power output performance of the first battery B1.

[0116] (6) The ECU 71, under normal control after the second condition is met, uses the power output from the first battery B1 to charge the second battery B2. As a result, the second battery B2, which can achieve sufficiently high power output performance through power path control and second priority control, ensures sufficient remaining power and promotes the heating of the first battery B1, thereby further increasing the power output performance of the first battery B1.

[0117] (7) The cooling circuit ECU76 makes the first cooling output of the first cooling device 91 shorter during the period before the second condition is met, i.e., the period during which the second battery B2 is mainly heated by power path control and second priority control, than after the second condition is met. As a result, the time until the second condition is met can be shortened, i.e., the time until the first battery B1 can be used for drivability.

[0118] (8) The cooling circuit ECU76 causes the second cooling output of the second cooling device 92, which cools the second battery B2, to be less during the period before the first condition is met (i.e., the period during which the second battery B2 is heated by power path control) than during the period after the first condition is met (i.e., the period during which the second battery B2 is heated by executing the second priority control). This shortens the time until the first condition is met, i.e., until propulsion force for moving the vehicle V can be generated.

[0119] The above description illustrates one embodiment of the present invention, but the invention is not limited thereto. The structure of minor parts can be appropriately modified within the scope of the spirit of the invention.

[0120] For example, in the above embodiment, under cold start control, the condition related to the total output limit Ptot_max of all batteries combining the first battery B1 and the second battery B2 is met ( Figure 5 Step S12) transitions from power path control to second priority control, but the invention is not limited thereto. For example, the transition from normal control to second priority control may also occur when conditions such as the first output limit P1_max of the first battery B1 or the second output limit P2_max of the second battery B2 are met.

[0121] Furthermore, in the above embodiment, under cold start control, the condition related to the first output upper limit P1_max of the first battery B1 is met ( Figure 4 Step S2) transitions from second priority control to normal control, but the present invention is not limited thereto. For example, the transition from second priority control to normal control may also occur when conditions such as satisfying the second output upper limit P2_max for the second battery B2, or the total output upper limit Ptot_max of all batteries combining the first battery B1 and the second battery B2 are met.

[0122] Figure Labels

[0123] V: Vehicle

[0124] 1: Power System

[0125] 2: First power circuit

[0126] B1: First battery (first energy storage device)

[0127] 3: Second power circuit

[0128] B2: Second battery (second energy storage device)

[0129] 4: Load circuit

[0130] 43: Power Converter

[0131] 5: Voltage converter

[0132] 7: Electronic Control Unit Group

[0133] 71: ECU Management (Electrical Control System, First Cooling Output Control Device)

[0134] 72: Motor ECU (Electric Control Unit)

[0135] 73: Converter ECU (Electrical Control Unit)

[0136] 76: Cooling circuit ECU (first cooling output control device, second cooling output control device)

[0137] 9: Cooling circuit

[0138] 91: First cooling device

[0139] 92: Second cooling device

Claims

1. A power supply system comprising: The first power circuit has a first energy storage device; The second power circuit has a second energy storage device with a smaller heat capacity than the first energy storage device; A voltage converter that transforms voltage between the first power circuit and the second power circuit; A power converter that converts power between the first power circuit and the rotating motor; as well as, The power control means controls the charging and discharging of the first energy storage device and the second energy storage device by operating the voltage converter and the power converter; The power supply system is characterized by: The power control method, after being started, Power path control is performed to transmit and receive power between the first and second energy storage devices until a first condition related to the power output performance of either or both of the first and second energy storage devices is met. A second priority control is executed, which prioritizes the discharge of the second energy storage device over the first energy storage device, until a second condition related to the power output performance of either or both the first and second energy storage devices is met. The first condition is that the sum of the upper limit of the power that can be output from the first energy storage device (i.e., the first output limit) and the upper limit of the power that can be output from the second energy storage device (i.e., the second output limit) exceeds the first condition threshold. The second condition is that the first output upper limit exceeds a second condition threshold that is defined as being greater than the first condition threshold.

2. The power supply system according to claim 1, characterized in that: Compared to the first energy storage device, the second energy storage device has a higher output weight density and a lower energy weight density.

3. A power supply system comprising: The first power circuit has a first energy storage device; The second power circuit has a second energy storage device. Compared with the first energy storage device, the second energy storage device has a higher output weight density and a lower energy weight density. A voltage converter that transforms voltage between the first power circuit and the second power circuit; A power converter that converts power between the first power circuit and the rotating motor; as well as, The power control means controls the charging and discharging of the first energy storage device and the second energy storage device by operating the voltage converter and the power converter; The power supply system is characterized by: The power control method, after being started, Power path control is performed to transmit and receive power between the first and second energy storage devices until a first condition related to the power output performance of either or both of the first and second energy storage devices is met. A second priority control is executed, which prioritizes the discharge of the second energy storage device over the first energy storage device, until a second condition related to the power output performance of either or both the first and second energy storage devices is met. The first condition is that the sum of the upper limit of the power that can be output from the first energy storage device (i.e., the first output limit) and the upper limit of the power that can be output from the second energy storage device (i.e., the second output limit) exceeds the first condition threshold. The second condition is that the first output upper limit exceeds a second condition threshold that is defined as being greater than the first condition threshold.

4. The power supply system according to any one of claims 1 to 3, characterized in that: It also includes means for obtaining the required output of the rotary motor. The power control means, under the second priority control, operates the voltage converter and the power converter so that the insufficient portion obtained by subtracting the upper limit of the power that can be output from the second energy storage device from the required output from the first energy storage device, i.e., the second output upper limit, can be output.

5. The power supply system according to any one of claims 1 to 3, characterized in that: The power control means perform ordinary control that prioritizes the discharge of the first energy storage device over the second energy storage device.

6. The power supply system according to claim 5, characterized in that: The power control means, under the normal control, uses the power output from the first energy storage device to charge the second energy storage device.

7. The power supply system according to any one of claims 1 to 3, characterized in that... Also includes: The first cooling device cools the first energy storage device; as well as, A first cooling output control device controls the first cooling output of the first cooling device; Furthermore, the first cooling output control device causes the first cooling output to be smaller during the period before the second condition is met than after the second condition is met.

8. The power supply system according to any one of claims 1 to 3, characterized in that... Also includes: The second cooling device cools the second energy storage device. as well as, The second cooling output control device controls the second cooling output of the second cooling device. Furthermore, the second cooling output control device causes the second cooling output to be smaller during the period before the first condition is met than after the first condition is met.

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