Power supply system

Abstract

To provide a power supply system capable of outputting electric power from two power storage devices with small circuit loss.SOLUTION: A power supply system comprises: electric power circuits that connect first and second batteries with a load circuit; electric power control means for controlling output electric power of the first and second batteries by operating the first and second electric power circuits; and allowable output upper limit acquisition means for acquiring a first allowable output upper limit P1_lim with respect to the output electric power of the first battery and a second allowable output upper limit P2_lim with respect to the output electric power of the second battery. On the basis of a temperature T1 of the first battery and a temperature T2 of the second battery, the electric power control means performs battery output control mode switching between a first priority output mode, in which the output electric power of the first battery is increased to the first allowable output upper limit P1_lim prior to the second battery, and a second priority output mode, in which the output electric power of the second battery is increased to the second allowable output upper limit P2_lim prior to the first battery.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a power supply system. More specifically, it relates to a power supply system including two power storage devices.

Background Art

[0002] In recent years, the development of electric vehicles such as electric transportation equipment equipped with a drive motor as a power generation source and hybrid vehicles equipped with a drive motor and an internal combustion engine as power generation sources has been active. Such electric vehicles are also equipped with a power storage device (such as a battery and a capacitor) to supply electric energy to the drive motor. In recent years, those equipped with a plurality of power storage devices having different characteristics have also been developed.

[0003] For example, Patent Document 1 shows a power supply system for an electric vehicle in which a capacitive battery and an output-type battery are connected to a drive motor via a power circuit. According to a power supply system including two batteries having different characteristics such as this, for example, it is possible to travel only by the power output from the capacitive battery or to travel by the power obtained by combining the power output from the capacitive battery and the power output from the output-type battery.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, when power is supplied from a battery to a drive motor via a power circuit, various circuit losses occur. Among the circuit losses occurring in the entire power system, the loss due to the internal resistance of the battery is particularly the largest. However, in the conventional power supply system, the circuit losses that occur when power is output from each battery are not sufficiently considered.

[0006] An object of the present invention is to provide a power supply system capable of outputting power from two power storage devices with low circuit losses.

Means for Solving the Problems

[0007] (1) The power supply system according to the present invention (for example, the power supply system 1 described later) includes a first power storage device (for example, the first battery B1 described later), a second power storage device (for example, the second battery B2 described later), a load circuit including a rotating electrical machine (for example, the drive motor M described later) (for example, the load circuit 4 described later), a power circuit (for example, the first power circuit 2 and the second power circuit 3 described later) that connects the first and second power storage devices and the load circuit, power control means (for example, the management ECU 71, the motor ECU 72, and the converter ECU 73 described later) that controls the output power of the first and second power storage devices by operating the power circuit, temperature acquisition means (for example, the first battery ECU 74, the second battery ECU 75, the first battery sensor unit 81, and the second battery sensor unit 82 described later) that acquires a first temperature (for example, the first battery temperature T1 described later) that is the temperature of the first power storage device and a second temperature (for example, the second battery temperature T2 described later) that is the temperature of the second power storage device, and allowable output upper limit acquisition means (for example, the management ECU 71, the first battery ECU 74, the second battery ECU 75, the first battery sensor unit 81, and the second battery sensor unit 82 described later) that acquires a first allowable output upper limit (for example, the first allowable output upper limit P1_lim described later) for the output power of the first power storage device and a second allowable output upper limit (for example, the second allowable output upper limit P2_lim described later) for the output power of the second power storage device. The power control means is characterized by switching the control mode to a first priority output mode in which the output power of the first power storage device is increased to the first allowable output upper limit with priority over the second power storage device or a second priority output mode in which the output power of the second power storage device is increased to the second allowable output upper limit with priority over the first power storage device based on the first and second temperatures.

[0008] (2) In this case, the power supply system further includes a cooling circuit (for example, the cooling circuit 9 described later, and its first cooling device 91 and second cooling device 92) for cooling the first power storage device and the second power storage device, and a cooling output control means (for example, the cooling circuit ECU 76 described later) for controlling a first cooling output to the first power storage device by the cooling circuit and a second cooling output to the second power storage device by the cooling circuit. When the first temperature is less than a first temperature reference value (for example, the first temperature reference value T1_bs described later), the cooling output control means reduces the first cooling output compared to the case where the first temperature is equal to or higher than the first temperature reference value. When the second temperature is less than a second temperature reference value (for example, the second temperature reference value T2_bs described later), it is preferable that the second cooling output is reduced compared to the case where the second temperature is equal to or higher than the second temperature reference value.

[0009] (3) In this case, when the first temperature is equal to or higher than the first temperature reference value and the second temperature is less than the second temperature reference value, the power control means preferably sets the control mode to the first priority output mode. When the first temperature is less than the first temperature reference value and the second temperature is equal to or higher than the second temperature reference value, it is preferable that the control mode is set to the second priority output mode.

[0010] (4) In this case, the power supply system further includes a loss acquisition means (for example, the management ECU 71 described later) for acquiring a first loss (for example, the first loss Ploss1 described later) generated in the first power storage device and the power circuit when the control mode is the first priority output mode, and a second loss (for example, the second loss Ploss2 described later) generated in the second power storage device, the second power storage device, and the power circuit when the control mode is the second priority output. When the first temperature is equal to or higher than the first temperature reference value and the second temperature is equal to or higher than the second temperature reference value, if the first loss is greater than the second loss, the power control means preferably sets the control mode to the second priority output mode. If the second loss is greater than the first loss, it is preferable that the control mode is set to the first priority output mode.

[0011] (5) In this case, the power supply system further includes a first power circuit having the first power storage device (for example, the first power circuit 2 described later), a second power circuit having the second power storage device (for example, the second power circuit 3 described later), a voltage converter that converts a voltage between the first power circuit and the second power circuit (for example, the voltage converter 5 described later), and a power converter that connects the first power circuit and the rotating electrical machine (for example, the power converter 43 described later). When the first temperature is equal to or higher than the first temperature reference value and the second temperature is equal to or higher than the second temperature reference value, it is preferable that the power control means sets the control mode to the first priority output mode.

[0012] (6) In this case, the heat capacity of the second power storage device is smaller than the heat capacity of the first power storage device. When the first temperature is lower than the first temperature reference value and the second temperature is lower than the second temperature reference value, it is preferable that the power control means sets the control mode to the second priority output mode.

Advantages of the Invention

[0013] (1) Among the circuit losses occurring in a power supply system in which a first power storage device and a second power storage device are connected to a load circuit by a power circuit, the circuit loss occurring particularly in the first power storage device or the second power storage device is the largest. Also, the circuit losses occurring in these first and second power storage devices vary depending on their respective temperatures. In contrast, in the present invention, the power control means, based on the first and second temperatures, switches the control mode to a first priority output mode in which the output power of the first power storage device is increased to the first allowable output upper limit with priority over the second power storage device, or a second priority output mode in which the output power of the second power storage device is increased to the second allowable output upper limit with priority over the first power storage device. Therefore, according to the present invention, it is possible to switch the power storage device to be preferentially used so that the circuit loss occurring in the entire power supply system is reduced. Also, by reducing the circuit loss, it becomes possible to continuously drive the rotating electrical machine for a long time.

[0014] (2) In the present invention, when the first temperature is lower than the first temperature reference value, the cooling output control means reduces the first cooling output by the cooling circuit compared to the case where the first temperature is equal to or higher than the first temperature reference value. When the second temperature is lower than the second temperature reference value, the cooling output control means reduces the second cooling output by the cooling circuit compared to the case where the second temperature is lower than the second temperature reference value. As a result, while rapidly increasing the first temperature and the second temperature respectively, the power consumption in the cooling circuit can be suppressed, so that the rotating electrical machine can be continuously driven for a longer time.

[0015] (3) When the first temperature is equal to or higher than the first temperature reference value and the second temperature is lower than the second temperature reference value, the power control means sets the control mode to the first priority output mode and preferentially discharges the relatively high-temperature first power storage device. Thereby, the circuit loss can be made smaller than in the case of preferentially discharging the relatively low-temperature second power storage device. Also, when the first temperature is lower than the first temperature reference value and the second temperature is equal to or higher than the second temperature reference value, the power control means sets the control mode to the second priority output mode and preferentially discharges the relatively high-temperature second power storage device. Thereby, the circuit loss can be made smaller than in the case of preferentially discharging the relatively low-temperature first power storage device.

[0016] (4) In the present invention, the loss acquisition means acquires the first loss when the control mode is the first priority output mode and the second loss when the control mode is the second priority output mode. Also, when the first temperature is equal to or higher than the first temperature reference value and the second temperature is equal to or higher than the second temperature reference value, if the first loss is greater than the second loss, the power control means sets the control mode to the second priority output mode with lower loss, and if the second loss is greater than the first loss, the power control means sets the control mode to the first priority output mode with lower loss. Thereby, the circuit loss in the power supply system can be further reduced.

[0017] (5) In the present invention, the first power storage device is connected to the rotating electrical machine via a power converter, and the second power storage device is connected to the rotating electrical machine via a power converter and a voltage converter. Therefore, assuming that the circuit loss in the first power storage device is equal to the circuit loss in the second power storage device, in the second priority output mode, more power passes through the voltage converter than in the first priority output mode, so the loss is greater in the second priority output mode than in the first priority output mode. Thus, when the first temperature is equal to or higher than the first temperature reference value and the second temperature is equal to or higher than the second temperature reference value, the power control means sets the control mode to the first priority output mode with lower loss. Thereby, the circuit loss in the power supply system can be further reduced.

[0018] (6) In the present invention, when the first temperature is lower than the first temperature reference value and the second temperature is lower than the second temperature reference value, the power control means sets the control mode to the second priority output mode and preferentially discharges from the second power storage device having a relatively small heat capacity. Thereby, the second power storage device can be quickly heated up, and the circuit loss in the power supply system can be further reduced.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5A

Figure 5B

Figure 6

Figure 7

Mode for carrying out the invention

[0020] <First Embodiment> Hereinafter, the first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing the configuration of a four-wheeled electric vehicle V (hereinafter simply referred to as "vehicle") equipped with the power supply system 1 according to the present embodiment. In the present embodiment, the case where the power supply system 1 is mounted on a four-wheeled vehicle V will be described, but the present invention is not limited to this. The power supply system according to the present invention may be applied not only to a four-wheeled vehicle V but also to a moving body that moves by a driving force generated by a rotating electric machine, such as a saddle-riding type vehicle, a ship, a robot, and an unmanned aerial vehicle.

[0021] The vehicle V includes drive wheels W, a drive motor M as a rotating electric machine connected to the drive wheels W, and a power supply system 1 that exchanges electric power between the drive motor M and the first battery B1 and the second battery B2 described later. In the present embodiment, the vehicle V will be described as an example that mainly accelerates and decelerates by the power generated by the drive motor M, but the present invention is not limited to this. The vehicle V may be a so-called hybrid vehicle equipped with a drive motor M and an engine as power generation sources.

[0022] The drive motor M is connected to the drive wheels W via a power transmission mechanism (not shown). The torque generated by the drive motor M by supplying three-phase AC power from the power supply system 1 to the drive motor M is transmitted to the drive wheels W via a power transmission mechanism (not shown), rotates the drive wheels W, and causes the vehicle V to travel. Further, the drive motor M exhibits the function of a generator when the vehicle V decelerates, generates regenerative power, and applies a regenerative braking torque corresponding to the magnitude of the regenerative power to the drive wheels W. The regenerative power generated by the drive motor M is appropriately charged to the batteries B1 and B2 of the power supply system 1.

[0023] The power supply system 1 includes a first power circuit 2 to which a first battery B1 is connected, a second power circuit 3 to which a second battery B2 is connected, a voltage converter 5 that connects 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 that cools the first battery B1 and the second battery B2, and an electronic control unit group 7 that controls the flow of power in these power circuits 2, 3, 4, the charging and discharging of the batteries B1, B2, and the cooling output of the cooling circuit 9 by operating these power circuits 2, 3, 4, the cooling circuit 9, and the voltage converter 5. The electronic control unit group 7 includes a 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, each of which is a computer.

[0024] The first battery B1 is a secondary battery capable of both discharging, which converts chemical energy into electrical energy, and charging, which converts electrical energy into chemical energy. Hereinafter, the case where a so-called lithium-ion battery that performs charging and discharging by the movement of lithium ions between electrodes is used as the first battery B1 will be described, but the present invention is not limited thereto.

[0025] The first battery B1 is provided with a first battery sensor unit 81 for estimating the internal state of the first battery B1. The first battery sensor unit 81 is composed of a plurality of sensors that detect physical quantities necessary for obtaining the state of charge (the stored amount of the battery expressed as a percentage) corresponding to the remaining amount of the first battery B1, the temperature, etc. in the first battery ECU 74, and transmit a signal corresponding to the detected value to the first battery ECU 74. More specifically, the first battery sensor unit 81 is composed of a voltage sensor that detects the terminal voltage of the first battery B1, a current sensor that detects the current flowing through the first battery B1, a temperature sensor that detects the temperature of the first battery B1, and the like.

[0026] The second battery B2 is a secondary battery capable of both discharging, which converts chemical energy into electrical energy, and charging, which converts electrical energy into chemical energy. Hereinafter, the case where a so-called lithium-ion battery that performs charge and discharge by the movement of lithium ions between electrodes is used as this second battery B2 will be described, but the present invention is not limited thereto. For the second battery B2, for example, a capacitor may be used.

[0027] The second battery B2 is provided with a second battery sensor unit 82 for estimating the internal state of the second battery B2. The second battery sensor unit 82 is composed of a plurality of sensors that detect physical quantities necessary for obtaining the state of charge, temperature, etc. of the second battery B2 in the second battery ECU 75 and transmit a signal corresponding to the detected value to the second battery ECU 75. More specifically, the second battery sensor unit 82 is composed of a voltage sensor that detects the terminal voltage of the second battery B2, a current sensor that detects the current flowing through the second battery B2, a temperature sensor that detects the temperature of the second battery B2, and the like.

[0028] Here, the characteristics of the first battery B1 and the characteristics of the second battery B2 are compared. The first battery B1 has a lower output weight density and a higher energy weight density than the second battery B2. Also, the first battery B1 has a larger discharge capacity than the second battery B2. That is, the first battery B1 is superior to the second battery B2 in terms of energy weight density. Note that the energy weight density is the amount of electric power per unit weight [Wh / kg], and the output weight density is the electric power per unit weight [W / kg]. Therefore, the first battery B1 with excellent energy weight density is a capacity-type capacitor mainly for high capacity, and the second battery B2 with excellent output weight density is an output-type capacitor mainly for high output. For this reason, in the power supply system 1, the first battery B1 is used as the main power supply, and the second battery B2 is used as a secondary power supply to supplement this first battery B1. Also, the second battery B2 has a smaller heat capacity than the first battery B1. Therefore, the temperature of the second battery B2 rises more quickly than that of the first battery B1.

[0029] The first power circuit 2 includes a first battery B1, first power lines 21p and 21n that connect the positive and negative electrodes of the first battery B1 to the positive and negative terminal electrodes on the high-voltage side of the voltage converter 5, and a positive electrode contactor 22p and a negative electrode contactor 22n provided on these first power lines 21p and 21n.

[0030] The contactors 22p and 22n are of the normally open type, which are open and cut off the conduction between the two electrodes of the first battery B1 and the first power lines 21p and 21n when no command signal is input from the outside, and are closed and connect the first battery B1 and the first power lines 21p and 21n when a command signal is input. These contactors 22p and 22n open and close according to a command signal transmitted from the first battery ECU 74. The positive electrode contactor 22p is a precharge contactor having a precharge resistor for relaxing the inrush current to a plurality of smoothing capacitors provided in the first power circuit 2, the load circuit 4, etc.

[0031] The second power circuit 3 includes a second battery B2, second power lines 31p and 31n that connect the positive and negative electrodes of the second battery B2 to the positive and negative terminal electrodes on the low-voltage side of the voltage converter 5, a positive electrode contactor 32p and a negative electrode contactor 32n provided on these second power lines 31p and 31n, and a current sensor 33 provided on the second power line 31p.

[0032] The contactors 32p and 32n are of the normally open type, which are open and cut off the conduction between the two electrodes of the second battery B2 and the second power lines 31p and 31n when no command signal is input from the outside, and are closed and connect the second battery B2 and the second power lines 31p and 31n when a command signal is input. These contactors 32p and 32n open and close according to a command signal transmitted from the second battery ECU 75. The positive electrode contactor 32p is a precharge contactor having a precharge resistor for relaxing the inrush current to a plurality of smoothing capacitors provided in the first power circuit 2, the load circuit 4, etc.

[0033] The current sensor 33 transmits a detection signal corresponding to the current flowing through the second power line 31p, that is, the passing current flowing through the voltage converter 5, to the converter ECU 73. In this embodiment, the direction of the passing current is defined such that the direction from the second power circuit 3 side to the first power circuit 2 side is positive, and the direction from the first power circuit 2 side to the second power circuit 3 side is negative. That is, the passing current of the voltage converter 5 is positive when the second battery B2 discharges and negative when the second battery B2 charges.

[0034] The load circuit 4 includes a vehicle accessory 42, a power converter 43 to which the drive motor M is connected, and load power lines 41p and 41n that connect the vehicle accessory 42 and the power converter 43 to the first power circuit 2.

[0035] The vehicle accessory 42 is composed of a plurality of electrical loads such as a battery heater, an air compressor, a DC-DC converter, and an in-vehicle charger. The vehicle accessory 42 is connected to the first power lines 21p and 21n of the first power circuit 2 by the load power lines 41p and 41n, and operates by consuming the power in the first power lines 21p and 21n. Information regarding the operating states of the various electrical loads that make up the vehicle accessory 42 is transmitted to, for example, the management ECU 71.

[0036] The power converter 43 is connected to the first power lines 21p and 21n in parallel with the vehicle auxiliary machine 42 by the 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 PWM inverter by pulse width modulation, including a bridge circuit configured by bridge-connecting a plurality of switching elements (for example, IGBTs), and has a function of converting DC power and AC power. The power converter 43 is connected to the first power lines 21p and 21n on its DC input / output side, and is connected to the U-phase, V-phase, and W-phase coils of the drive motor M on its AC input / output side. The power converter 43 drives the switching elements of each phase to be turned on / off according to the gate drive signals generated at a predetermined timing from a gate drive circuit (not shown) of the motor ECU 72, thereby converting the DC power on 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.

[0037] The voltage converter 5 connects the first power circuit 2 and the second power circuit 3, and converts the voltage between these two circuits 2 and 3. A known boost circuit is used for this voltage converter 5.

[0038] FIG. 2 is a diagram showing an example of the circuit configuration of the voltage converter 5. The voltage converter 5 connects the first power lines 21p and 21n to which the first battery B1 is connected and the second power lines 31p and 31n to which the second battery B2 is connected, and converts the voltage between these first power lines 21p and 21n and the second power lines 31p and 31n. The voltage converter 5 is a full-bridge type DCDC converter configured 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).

[0039] The low-voltage side terminals 56p and 56n are connected to the second power lines 31p and 31n, and the high-voltage side terminals 57p and 57n are connected to the first power lines 21p and 21n. The negative bus bar 55 is a wiring that connects the low-voltage side terminal 56n and the high-voltage side terminal 57n.

[0040] One end side of the first reactor L1 is connected to the low-voltage side terminal 56p, and the other end side 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 MOSFET, and a freewheeling diode connected to this power switching element. These high-arm element 53H and low-arm element 53L are connected in series in this order between the high-voltage side terminal 57p and the negative bus bar 55.

[0041] The collector of the power switching element of the first high-arm element 53H is connected to the high-voltage side terminal 57p, and its emitter is connected to the collector of the first low-arm element 53L. The emitter of the power switching element of the first low-arm element 53L is connected to the negative bus bar 55. The forward direction of the freewheeling diode provided in the first high-arm element 53H is in the direction from the first reactor L1 to the high-voltage side terminal 57p. Also, the forward direction of the freewheeling diode provided in the first low-arm element 53L is in the direction from the negative bus bar 55 to the first reactor L1.

[0042] One end side of the second reactor L2 is connected to the low-voltage side terminal 56p, and the other end side 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 a MOSFET, and a freewheeling diode connected to this power switching element. These high-arm element 54H and low-arm element 54L are connected in series in this order between the high-voltage side terminal 57p and the negative bus bar 55.

[0043] The collector of the power switching element of the second high arm element 54H is connected to the high voltage side terminal 57p, and its 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 forward direction of the freewheeling diode provided in the second high arm element 54H is from the second reactor L2 toward the high voltage side terminal 57p. Also, the forward direction of the freewheeling diode provided in the second low arm element 54L is from the negative bus 55 toward the second reactor L2.

[0044] The voltage converter 5 alternately turns on and 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 in accordance with a gate drive signal generated at a predetermined timing from a gate drive circuit (not shown) of the converter ECU 73, thereby converting the voltage between the first power lines 21p, 21n and the second power lines 31p, 31n.

[0045] The static voltage of the second battery B2 is basically maintained lower than the static voltage of the first battery B1. Therefore, basically, the voltage of the first power lines 21p, 21n is higher than the voltage of the second power lines 31p, 31n. Thus, when the converter ECU 73 drives the drive motor M 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 so that a boosting function is exhibited in the voltage converter 5. The boosting function refers to a function of boosting the power in the second power lines 31p, 31n to which the low voltage side terminals 56p, 56n are connected and outputting it to the first power lines 21p, 21n to which the high voltage side terminals 57p, 57n are connected, whereby a positive passing current flows from the second power lines 31p, 31n side to the first power lines 21p, 21n side. Also, when suppressing the discharge of the second battery B2 and driving the drive motor M using only the power output from the first battery B1, the converter ECU 73 turns off the voltage converter 5 so that no current flows from the first power lines 21p, 21n to the second power lines 31p, 31n.

[0046] When charging the first battery B1 and the second battery B2 with the regenerative power output from the drive motor M to the first power lines 21p and 21n during deceleration, the converter ECU 73 operates the voltage converter 5 so that the voltage converter 5 exhibits a step-down function. The step-down function refers to the function of stepping down the power in the first power lines 21p and 21n to which the high-voltage side terminals 57p and 57n are connected and outputting it to the second power lines 31p and 31n to which the low-voltage side terminals 56p and 56n are connected. As a result, a negative passing current flows from the first power lines 21p and 21n side to the second power lines 31p and 31n side.

[0047] Returning to FIG. 1, the first battery ECU 74 is a computer mainly responsible for monitoring the state of the first battery B1 and opening and closing the contactors 22p and 22n of the first power circuit 2. The first battery ECU 74 calculates various parameters representing the internal state of the first battery B1 based on a known algorithm using the detection values transmitted from the first battery sensor unit 81. More specifically, the temperature of the first battery B1 (hereinafter also referred to as the "first battery temperature"), the internal resistance of the first battery B1, the static voltage of the first battery B1, the closed-circuit voltage of the first battery B1, the first charge rate corresponding to the charge rate of the first battery B1, and the degree of deterioration of the first battery B1, etc. Information regarding the parameters representing the internal state of the first battery B1 acquired by the first battery ECU 74 is transmitted to, for example, the management ECU 71.

[0048] The second battery ECU 75 is a computer mainly responsible for monitoring the state of the second battery B2 and opening and closing the contacts 32p and 32n of the second power circuit 3. The second battery ECU 75 calculates various parameters representing the internal state of the second battery B2 based on a known algorithm using the detection values transmitted from the second battery sensor unit 82. More specifically, the temperature of the second battery B2 (hereinafter also referred to as the "second battery temperature"), the internal resistance of the second battery B2, the static voltage of the second battery B2, the closed-circuit voltage of the second battery B2, the second charge rate corresponding to the charge rate of the second battery B2, and the degree of deterioration of the second battery B2, etc. Information regarding the parameters representing the internal state of the second battery B2 acquired in the second battery ECU 75 is transmitted to, for example, the management ECU 71.

[0049] The management ECU 71 is a computer mainly responsible for managing the flow of power in the entire power supply system 1. The management ECU 71 executes a power management process, which will be described later with reference to FIG. 4, to generate an inverter passing power command signal corresponding to a command for the inverter passing power, which is the power passing through the power converter 43, and a converter passing power command signal corresponding to a command for the converter passing power, which is the power passing through the voltage converter 5.

[0050] The motor ECU 72 is a computer mainly responsible for operating the power converter 43 and controlling the flow of power between the first power circuit 2 and the drive motor M, that is, the flow of the inverter passing power. Hereinafter, the inverter passing power is considered positive when power flows from the first power circuit 2 to the drive motor M, that is, when the drive motor M is in the power running operation. The inverter passing power is considered negative when power flows from the drive motor M to the first power circuit 2, that is, when the drive motor M is in the regenerative operation. The motor ECU 72 operates the power converter 43 so that the inverter passing power corresponding to the command passes through the power converter 43 in response to the inverter passing power command signal transmitted from the management ECU 71. In other words, torque corresponding to the inverter passing power is generated in the drive motor M.

[0051] The converter ECU 73 is mainly a computer that operates the voltage converter 5 and controls the flow of power between the first power circuit 2 and the second power circuit 3, that is, the flow of converter passing power. In the following, the converter passing power is considered positive when power flows from the second power circuit 3 to the first power circuit 2, that is, when discharging power from the second battery B2 and supplying the first power circuit 2. Also, the converter passing power is considered negative when power flows from the first power circuit 2 to the second power circuit 3, that is, when charging the second battery B2 with the power in the first power circuit 2. The converter ECU 73 operates the voltage converter 5 so that the converter passing power corresponding to the command passes through the voltage converter 5 in accordance with the converter passing power command signal transmitted from the management ECU 71. More specifically, the converter ECU 73 calculates a target current, which is a target for the passing current in the voltage converter 5, based on the converter passing power command signal, and operates the voltage converter 5 according to a known feedback control algorithm so that the passing current detected by the current sensor 33 (hereinafter also referred to as "actual passing current") becomes the target current.

[0052] As described above, in the power supply system 1, the management ECU 71, the motor ECU 72, and the converter ECU 73 operate the voltage converter 5 and the power converter 43, and control the passing power in these voltage converter 5 and power converter 43, thereby controlling the first battery output power, which is the output power of the first battery B1, and the second battery output power, which is the output power of the second battery B2. Therefore, in the present embodiment, the power control means for controlling the first battery output power and the second battery output power is constituted by the management ECU 71, the motor ECU 72, and the converter ECU 73. More specifically, by controlling the converter passing power to P2 and the inverter passing power to P1 + P2 by the above power control means, the first battery output power and the second battery output power can be controlled to P1 and P2, respectively.

[0053] Figure 3 is a diagram showing the circuit configuration of the cooling circuit 9. 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.

[0054] The first cooling device 91 includes a first cooling water circulation path 911 including a cooling water flow path formed in a battery case that houses the first battery B1, a first heat exchanger 912 and a first cooling water pump 913 provided in the first cooling water circulation path 911, and a heating device 94 connected to the first cooling water circulation path 911.

[0055] The first cooling water pump 913 rotates according to a command input from the cooling circuit ECU 76 and circulates the cooling water in the first cooling water circulation path 911. The first heat exchanger 912 cools the cooling water heated by heat exchange with the first battery B1 by promoting heat exchange between the cooling water circulating in the first cooling water circulation path 911 and the outside air. The first heat exchanger 912 includes a radiator fan that rotates according to a command input from the cooling circuit ECU 76.

[0056] 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 provided in the bypass path 941, and three-way valves 944, 945 provided at the connection portions between both ends of the bypass path 941 and the first cooling water circulation path 911.

[0057] The heating pump 943 rotates according to a command input from the cooling circuit ECU 76 and circulates the cooling water in the first cooling water circulation path 911 and the bypass path 941. The heater 942 generates heat by consuming electric power supplied from a battery (not shown) and raises the temperature of the cooling water flowing through the bypass path 941.

[0058] The three-way valve 944, 945 opens and closes according to a command from the cooling circuit ECU 76, and switches the flow path of the cooling water between the first heat exchanger 912 side and the heater 942 side. Therefore, in the first cooling device 91, there are two functions: a cooling function of cooling the first battery B1 by circulating the cooling water cooled by the first heat exchanger 912, and a heating function of heating the first battery B1 by circulating the cooling water heated by the heater 942.

[0059] The cooling circuit ECU 76 controls the first cooling output of the first battery B1 by the first cooling device 91 by operating the first heat exchanger 912, the first cooling water pump 913, the heater 942, the heating pump 943, and the three-way valves 944, 945 based on the first battery temperature transmitted from the first battery ECU 74, the detection value of a first cooling water temperature sensor (not shown) that detects the temperature of the cooling water flowing through the first cooling water circulation path 911, the detection value of an outside air temperature sensor (not shown), and a command from the management ECU 71, etc. Here, the first cooling output is a parameter that increases or decreases according to the cooling performance of the first battery B1 by the first cooling device 91. For example, it is the rotational speed of the radiator fan provided in the first heat exchanger 912. The specific procedure for controlling the first cooling output in the cooling circuit ECU 76 will be described later.

[0060] The second cooling device 92 includes, for example, a cooling fan that supplies outside air into the battery case that houses the second battery B2. The second cooling device 92 rotates according to a command from the cooling circuit ECU 76, and cools the second battery B2 by supplying outside air into the battery case of the second battery B2.

[0061] The cooling circuit ECU 76 controls the second cooling output of the second battery B2 by the second cooling device 92 by operating the second cooling device 92 based on the second battery temperature transmitted from the second battery ECU 75, the detected value of the outside air temperature sensor, and commands from the management ECU 71. Here, the second cooling output is a parameter that increases or decreases according to the cooling performance of the second battery B2 by the second cooling device 92, and is, for example, the rotational speed of the cooling fan of the second cooling device 92. Specific procedures for controlling the second cooling output in the cooling circuit ECU 76 will be described later.

[0062] The third cooling device 93 includes a third cooling water circulation path 931 including a cooling water flow path formed in the housing where the voltage converter 5 and the power converter 43 are installed, and a third heat exchanger 932 and a third cooling water pump 933 provided in the third cooling water circulation path 931.

[0063] The third cooling water pump 933 rotates according to a command input from the cooling circuit ECU 76 and circulates the cooling water in the third cooling water circulation path 931. The third heat exchanger 932 cools the cooling water heated by heat exchange with the voltage converter 5 and the power converter 43 by promoting heat exchange between the cooling water circulating in the third cooling water circulation path 931 and the outside air. The third heat exchanger 932 includes a radiator fan that rotates according to a command input from the cooling circuit ECU 76.

[0064] The cooling circuit ECU 76 controls the third cooling output corresponding to the cooling performance of the voltage converter 5 and the power converter 43 by the third cooling device 93 by operating the third heat exchanger 932 and the third cooling water pump 933 based on the detected value of a cooling water temperature sensor (not shown) and commands from the management ECU 71.

[0065] As described above, in this embodiment, the first cooling device 91 that cools the first battery B1 and the third cooling device 93 that cools the voltage converter 5 and the like are water-cooled devices that cool by heat exchange with cooling water. The second cooling device 92 that cools the second battery B2 having a smaller heat capacity than the first battery B1 is an air-cooled device that cools by heat exchange with outside air. However, the present invention is not limited to this. The first cooling device 91 may be air-cooled, the second cooling device 92 may be water-cooled, or the third cooling device 93 may be air-cooled. Also, in this embodiment, the circulation flow path of the cooling water for cooling the first battery B1 and the circulation flow path of the cooling water for cooling the voltage converter 5 and the power converter 43 are separate systems, but the present invention is not limited to this. Both the voltage converter 5 and the power converter 43 or either of them may be cooled by the cooling water for cooling the first battery B1.

[0066] Figure 4 is a flowchart showing a specific procedure of the power management process. This power management process is repeatedly executed at a predetermined cycle in the management ECU 71 from when the driver turns on a start switch (not shown) to start the vehicle V and the power supply system 1 until the driver turns off the start switch again to stop the vehicle V and the power supply system 1.

[0067] First, in step S1, the management ECU 71 calculates the required driving torque by the driver based on the operation amounts of pedals such as the accelerator pedal and the brake pedal (see FIG. 1) by the driver, and by converting this required driving torque into electric power, calculates the requirement for the inverter passing power in the power converter 43, that is, the required inverter passing power Pmot_d corresponding to the required output in the drive motor M, and proceeds to step S2.

[0068] Next, in step S2, the management ECU 71 executes a target passing power calculation process, which will be described later with reference to FIGS. 5A and 5B, etc., based on the required inverter passing power Pmot_d calculated in step S1. As a result, the target converter passing power Pcnv_cmd corresponding to the target for the converter passing power and the target inverter passing power Pmot_cmd corresponding to the target for the inverter passing power are calculated. Then, the process proceeds to step S3.

[0069] Next, in step S3, the management ECU 71 generates a converter passing power command signal corresponding to the target converter passing power Pcnv_cmd, transmits this to the converter ECU 73, and then proceeds to step S8. As a result, the power corresponding to the target converter passing power Pcnv_cmd is charged and discharged from the second battery B2.

[0070] Next, in step S4, the management ECU 71 generates an inverter passing power command signal corresponding to the target inverter passing power Pmot_cmd, transmits this to the motor ECU 72, and ends the process of FIG. 4. As a result, the power corresponding to the target inverter passing power Pmot_cmd flows between the first power circuit 2 and the drive motor M. Also, as a result, the power obtained by subtracting the target converter passing power Pcnv_cmd from the target inverter passing power Pmot_cmd is charged and discharged from the first battery B1.

[0071] FIGS. 5A and 5B are flowcharts showing the specific procedure of the target passing power calculation process.

[0072] First, in step S11, the management ECU 71 acquires the first battery temperature T1 and the second battery temperature T2 from the first battery ECU 74 and the second battery ECU 75, respectively, and then proceeds to step S12.

[0073] Next, in step S12, the management ECU 71 acquires the first state of charge SOC1 and the second state of charge SOC2 from the first battery ECU 74 and the second battery ECU 75, respectively, and then proceeds to step S13.

[0074] Next, in step S13, the management ECU 71 searches a predetermined map based on the first battery temperature T1 and the first state of charge SOC1 acquired in steps S11 and S12, and calculates a first allowable output upper limit P1_lim corresponding to the upper limit of the allowable output power for the current first battery B1, and then proceeds to step S14.

[0075] Next, in step S14, the management ECU 71 searches a predetermined map based on the second battery temperature T2 and the second state of charge SOC2 acquired in steps S11 and S12, and calculates a second allowable output upper limit P2_lim corresponding to the upper limit of the allowable output power for the current second battery B2, and then proceeds to step S15.

[0076] Next, in step S15, the management ECU 71 determines whether the required inverter passing power Pmot_d acquired in step S1 is greater than or equal to the sum of the first allowable output upper limit P1_lim and the second allowable output upper limit P2_lim (that is, the upper limit of the allowable output power for the total batteries including the first battery B1 and the second battery B2). If the determination result in step S15 is YES, the management ECU 15 proceeds to step S16, performs a limit process to limit the required inverter passing power Pmot_d to be less than or equal to the sum of the first allowable output upper limit P1_lim and the second allowable output upper limit P2_lim, and then proceeds to step S17. More specifically, the management ECU 71 limits the required inverter passing power Pmot_d by redefining the sum of the first allowable output upper limit P1_lim and the second allowable output upper limit P2_lim as the required inverter passing power Pmot_d. If the determination result in step S15 is NO, the management ECU 71 proceeds to step S17 without performing the limit process in step S16.

[0077] Next, in step S17, the management ECU 71 searches a control mode determination table as illustrated in FIG. 6 based on the first battery temperature T1 and the second battery temperature T2 acquired in step S11, sets a battery output control mode corresponding to the current temperature states of the first battery B1 and the second battery B2, and proceeds to step S20.

[0078] FIG. 6 is a diagram showing an example of the control mode determination table. As shown in FIG. 6, the management ECU 71 can set the battery output control mode to any one of a first priority output mode, a second priority output mode, and a low-loss battery priority output mode.

[0079] In FIG. 6, the "appropriate temperature" of the first battery B1 means a state where the first battery temperature T1 is equal to or higher than a predetermined first temperature reference value T1bs, and the "low temperature" of the first battery B1 means a state where the first battery temperature T1 is lower than the first temperature reference value T1bs. Also, the "appropriate temperature" of the second battery B2 means a state where the second battery temperature T2 is equal to or higher than a predetermined second temperature reference value T2bs, and the "low temperature" of the second battery B2 means a state where the second battery temperature T2 is lower than the second temperature reference value T2bs. Here, the first temperature reference value T1bs is set, for example, within the target temperature range of the first battery B1 in which the output characteristics of the first battery B1 are in the most preferable state, and more specifically, at the lower limit value of this target temperature range. Also, the second temperature reference value T2bs is set, for example, within the target temperature range of the second battery B2 in which the output characteristics of the second battery B2 are in the most preferable state, and more specifically, at the lower limit value of this target temperature range.

[0080] When the management ECU 71 sets the battery output control mode to the first priority output mode, it increases the output power of the first battery B1 to the first allowable output upper limit P1_lim prior to the second battery B2. That is, when the required inverter passing power Pmot_d does not exceed the first allowable output upper limit P1_lim, all of the required inverter passing power Pmot_d is covered by the first battery B1, and when the required inverter passing power Pmot_d exceeds the first allowable output upper limit P1_lim, the target converter passing power Pcnv_cmd and the target inverter passing power Pmot_cmd are calculated such that this shortage is covered by the second battery B2.

[0081] When the management ECU 71 sets the battery output control mode to the second priority output mode, it increases the output power of the second battery B2 to the second allowable output upper limit P2_lim prior to the first battery B1. That is, when the required inverter passing power Pmot_d does not exceed the second allowable output upper limit P2_lim, all of the required inverter passing power Pmot_d is covered by the second battery B2, and when the required inverter passing power Pmot_d exceeds the second allowable output upper limit P2_lim, the target converter passing power Pcnv_cmd and the target inverter passing power Pmot_cmd are calculated such that this shortage is covered by the first battery B1.

[0082] When the management ECU 71 sets the battery output control mode to the low-loss battery priority output mode, as described below, it compares the losses that occur in the entire power supply system 1 when the first battery B1 is preferentially output with the losses that occur in the entire power supply system 1 when the second battery B2 is preferentially output, and preferentially outputs the battery with the lower loss.

[0083] According to the control mode determination table illustrated in FIG. 6, when the first battery B1 is at an appropriate temperature and the second battery B2 is at a low temperature (T1≧T1bs and T2<T2bs), the management ECU 71 sets the battery output control mode to the first priority output mode in order to preferentially output power from the first battery B1 that is at an appropriate temperature and has low losses in the battery. When the first battery B1 is at a low temperature and the second battery B2 is at an appropriate temperature (T1<T1bs and T2≧T2bs), the management ECU 71 sets the battery output control mode to the second priority output mode in order to preferentially output power from the second battery B2 that is at an appropriate temperature and has low losses in the battery.

[0084] When both the first battery B1 and the second battery B2 are at an appropriate temperature (T1≧T1bs and T2≧T2bs), the management ECU 71 sets the battery output control mode to the low-loss battery priority output mode. Also, when both the first battery B1 and the second battery B2 are at a low temperature (T1<T1bs and T2<T2bs), that is, when it is considered that large losses will occur regardless of which battery is used, the battery output control mode is set to the second priority output mode in order to preferentially output power from the second battery B2 that has a smaller heat capacity and can be quickly heated up.

[0085] Returning to FIG. 5B, in step S20, the management ECU 71 sets the required inverter passing power Pmot_d as the target inverter passing power Pmot_cmd, and proceeds to step S21.

[0086] Next, in step S21, the management ECU 71 determines whether the battery output control mode set in step S17 is the low-loss battery priority output mode. If the determination result in step S21 is NO, the management ECU 71 proceeds to step S22.

[0087] In step S22, the management ECU 71 determines whether the battery output control mode set in step S17 is the first priority output mode. If the determination result in step S22 is YES, the management ECU 71 proceeds to step S23.

[0088] In step S23, the management ECU 71 determines whether the required inverter passing power Pmot_d is greater than or equal to the first allowable output upper limit P1_lim. If the determination result in step S23 is YES, the management ECU 71 proceeds to step S24, subtracts the first allowable output upper limit P1_lim from the required inverter passing power Pmot_d to obtain a value, sets this value as the target converter passing power Pcnv_cmd, and ends the target passing power calculation process. If the determination result in step S23 is NO, the management ECU 71 proceeds to step S25, sets the value 0 as the target converter passing power Pcnv_cmd, and ends the target passing power calculation process.

[0089] If the determination result in step S22 is NO, that is, when the battery output control mode is the second priority output mode, the management ECU 71 proceeds to step 26. In step S26, the management ECU 71 determines whether the required inverter passing power Pmot_d is greater than or equal to the second allowable output upper limit P2_lim. If the determination result in step S26 is YES, the management ECU 71 proceeds to step S27, sets the second allowable output upper limit P2_lim as the target converter passing power Pcnv_cmd, and ends the target passing power calculation process. If the determination result in step S26 is NO, the management ECU 71 proceeds to step S28, sets the required inverter passing power Pmot_d as the target converter passing power Pcnv_cmd, and ends the target passing power calculation process.

[0090] If the determination result in step S21 is YES, that is, when the battery output control mode is the low-loss battery priority output mode, the management ECU 71 proceeds to step S29.

[0091] In step S29, when the management ECU 71 sets the battery output control mode to the first priority output control mode, the management ECU 71 calculates a first loss Ploss1 corresponding to the losses generated in the first battery B1, the second battery B2, and the voltage converter 5, and a second loss Ploss2 corresponding to the losses generated in the first battery B1, the second battery B2, and the voltage converter 5 when the battery output control mode is set to the second priority output control mode, and then proceeds to step S30.

[0092] More specifically, the management ECU 71 first acquires the temperature, internal resistance, charge rate, and degree of deterioration of each of the first battery B1 and the second battery B2 from the first battery ECU 74 and the second battery ECU 75. Next, when the battery output control mode is set to the first priority output control mode, the management ECU 71 calculates the power output from each of the batteries B1 and B2 and the power passing through the voltage converter 5, and calculates the first loss Ploss1 by using these powers and the acquired temperature, internal resistance, charge rate, degree of deterioration, etc. Further, when the battery output control mode is set to the second priority output mode, the management ECU 71 calculates the power output from each of the batteries B1 and B2 and the power passing through the voltage converter 5, and calculates the second loss Ploss2 by using these powers and the acquired temperature, internal resistance, charge rate, degree of deterioration, etc.

[0093] In step S30, the management ECU 71 determines whether the first loss Ploss1 is greater than the second loss Ploss2. If the determination result in step S30 is YES, the management ECU 71 proceeds to step S26 to set the battery output control mode to the lower-loss second priority output mode. If the determination result is NO, the management ECU 71 proceeds to step S23 to set the battery output control mode to the lower-loss first priority output mode.

[0094] Returning to FIG. 3, a procedure for controlling the first cooling output and the second cooling output by the cooling circuit ECU 76 will be described.

[0095] The cooling circuit ECU 76 switches the cooling output control mode for controlling the first and second cooling outputs based on the first battery temperature T1 and the second battery temperature T2. As shown in FIG. 6, the cooling circuit ECU 76 can independently set the cooling output control mode of the first cooling output and the cooling output control mode of the second cooling output to either the normal mode or the low output mode.

[0096] According to the control mode determination table illustrated in FIG. 6, when the first battery B1 is at an appropriate temperature (T1 ≥ T1bs), the management ECU 71 sets the cooling output control mode of the first cooling output to the normal mode, and when the first battery B1 is at a low temperature (T1 < T1bs), the management ECU 71 sets the cooling output control mode of the first cooling output to the low output mode. Also, when the second battery B2 is at an appropriate temperature (T2 ≥ T2bs), the management ECU 71 sets the cooling output control mode of the second cooling output to the normal mode, and when the second battery B2 is at a low temperature (T2 < T2bs), the management ECU 71 sets the cooling output control mode of the second cooling output to the low output mode.

[0097] First, the case where the cooling output control mode is the normal mode will be described. When the cooling output control mode of the first cooling output is the normal mode, the cooling circuit ECU 76 calculates, based on a known first basic cooling algorithm using the first battery temperature transmitted from the first battery ECU 74, the detected value of the first coolant temperature sensor, and the detected value of the outside air temperature sensor, a first control input (for example, the duty ratio of the motor driving the radiator fan) for the first cooling device 91 such that the first battery temperature becomes the first target temperature defined within the target temperature range of the first battery B1, and controls the first cooling output by inputting this first control input to the first cooling device 91.

[0098] When the cooling output control mode of the second cooling output is the normal mode, the cooling circuit ECU 76 uses the second battery temperature transmitted from the second battery ECU 75 and the detected value of the outside air temperature sensor, and based on a known second basic cooling algorithm, so that the second battery temperature becomes the second target temperature defined within the target temperature range of the second battery B2, calculates the second control input (for example, the duty ratio of the motor driving the cooling fan) for the second cooling device 92, and controls the second cooling output by inputting this second control input to the second cooling device 92.

[0099] Next, the case where the cooling output control mode is the low output mode will be described. When the cooling output control mode of the first cooling output is the low output mode, the cooling circuit ECU 76 corrects the first control input to the side of reduced cooling performance by subtracting a predetermined correction value from the first control input calculated based on the above-described first basic cooling algorithm, and controls the first cooling output by inputting this corrected first control input to the first cooling device 91. For this reason, when the first battery B1 is at a low temperature, the cooling circuit ECU 76 makes the first cooling output smaller than when it is at an appropriate temperature.

[0100] When the cooling output control mode of the second cooling output is the low output mode, the cooling circuit ECU 76 corrects the second control input to the side of reduced cooling performance by subtracting a predetermined correction value from the second control input calculated based on the above-described second basic cooling algorithm, and controls the second cooling output by inputting this corrected second control input to the second cooling device 92. For this reason, when the second battery B2 is at a low temperature, the cooling circuit ECU 76 makes the second cooling output smaller than when it is at an appropriate temperature.

[0101] According to the power supply system 1 according to this embodiment, the following effects are obtained. (1) In the power supply system 1, the management ECU 71 switches the battery output control mode based on the first battery temperature T1 and the second battery temperature T2 to the first priority output mode in which the output power of the first battery B1 is increased to the first allowable output upper limit P1_lim with priority over the second battery B2, or the second priority output mode in which the output power of the second battery B2 is increased to the second allowable output upper limit P2_lim with priority over the first battery B1. Therefore, according to the power supply system 1, it is possible to switch the battery to be preferentially used so that the circuit loss generated in the entire power supply system 1 is reduced. Also, by reducing the circuit loss, it is possible to increase the travelable distance of the vehicle V.

[0102] (2) When the first battery temperature T1 is less than the first temperature reference value T1bs, the cooling circuit ECU 76 reduces the first cooling output by the first cooling device 91 compared to the case where the first battery temperature T1 is equal to or higher than the first temperature reference value T1bs. When the second battery temperature T2 is less than the second temperature reference value T2bs, the cooling circuit ECU 76 reduces the second cooling output by the second cooling device 92 compared to the case where the second battery temperature T2 is less than the second temperature reference value T2bs. As a result, while rapidly increasing the first battery temperature T1 and the second battery temperature T2 respectively, the power consumption in the cooling devices 91 and 92 can be suppressed, so that the travelable distance of the vehicle V can be further increased.

[0103] (3) When the first battery temperature T1 is equal to or higher than the first temperature reference value T1bs and the second battery temperature T2 is less than the second temperature reference value T2bs, the management ECU 71 sets the battery output control mode to the first priority output mode and preferentially discharges the first battery B1 at an appropriate temperature. Thereby, the circuit loss can be made smaller than when preferentially discharging the relatively low-temperature second battery B2. Also, when the first battery temperature T1 is less than the first temperature reference value T1bs and the second battery temperature T2 is equal to or higher than the second temperature reference value T2bs, the management ECU 71 sets the battery output control mode to the second priority output mode and preferentially discharges the second battery B2 at an appropriate temperature. Thereby, the circuit loss can be made smaller than when preferentially discharging the relatively low-temperature first battery B1.

[0104] (4) The management ECU 71 acquires the first loss Ploss1 when the battery output control mode is the first priority output mode and the second loss Ploss2 when the battery output control mode is the second priority output mode. Also, when the first battery temperature T1 is equal to or higher than the first temperature reference value T1bs and the second battery temperature T2 is equal to or higher than the second temperature reference value T2bs, if the first loss Ploss1 is greater than the second loss Ploss2, the management ECU 71 sets the battery output control mode to the second priority output mode with lower loss, and if the second loss Ploss2 is greater than the first loss Ploss1, the management ECU 71 sets the battery output control mode to the first priority output mode with lower loss. Thereby, the circuit loss in the power supply system 1 can be further reduced.

[0105] (5) When the first battery temperature T1 is less than the first temperature reference value T1bs and the second battery temperature T2 is less than the second temperature reference value T2bs, the management ECU 71 sets the battery output control mode to the second priority output mode and preferentially discharges from the second battery B2 with a relatively small heat capacity. Thereby, the second battery B2 can be quickly heated up, and the circuit loss in the power supply system 1 can be further reduced.

[0106] <Second Embodiment> Next, a power supply system according to the second embodiment of the present invention will be described with reference to the drawings. The configuration of the control mode determination table of the power supply system according to this embodiment is different from that of the power supply system 1 according to the first embodiment.

[0107] FIG. 7 is a diagram showing an example of a control mode determination table referred to in the power supply system according to this embodiment. The control mode determination table shown in FIG. 7 is different from the control mode determination table shown in FIG. 6 in that the battery output control mode is different when both the first battery B1 and the second battery B2 are at an appropriate temperature.

[0108] According to the control mode determination table illustrated in FIG. 7, when both the first battery B1 and the second battery B2 are at an appropriate temperature (T1 ≧ T1bs and T2 ≧ T2bs), the management ECU sets the battery output control mode to the first priority output mode.

[0109] The power supply system according to this embodiment has the following effects. (6) In the power supply system, the first battery B1 is connected to the drive motor M via the power converter 43, and the second battery B2 is connected to the drive motor M via the power converter 43 and the voltage converter 5. Therefore, assuming that the circuit loss in the first battery B1 is equal to the circuit loss in the second battery B2, in the second priority output mode, more power passes through the voltage converter 5 than in the first priority output mode, so the loss is greater in the second priority output mode than in the first priority output mode. Therefore, when the first battery temperature T1 is equal to or higher than the first temperature reference value T1bs and the second battery temperature T2 is equal to or higher than the second temperature reference value T2bs, the management ECU sets the battery output control mode to the first priority output mode with lower loss. Thereby, the circuit loss in the power supply system can be further reduced.

[0110] As described above, one embodiment of the present invention has been described, but the present invention is not limited to this. Within the scope of the gist of the present invention, the detailed configuration may be appropriately changed.

Explanation of Reference Numerals

[0111] V... Vehicle (Moving Body) M... Driving Motor (Rotating Electric Machine) 1... Power System 2... First Power Circuit (Power Circuit) B1... First Battery (First Power Storage Device) 3... Second Power Circuit (Power Circuit) B2... Second Battery (Second Power Storage Device) 4... Load Circuit 43... Power Converter 5... Voltage Converter 7... Electronic Control Unit Group 71... Management ECU (Power Control Means, Allowable Output Upper Limit Acquisition Means, Loss Acquisition Means) 72... Motor ECU (Power Control Means) 73... Converter ECU (Power Control Means) 74... First Battery ECU (Temperature Acquisition Means, Allowable Output Upper Limit Acquisition Means) 75... Second Battery ECU (Temperature Acquisition Means, Allowable Output Upper Limit Acquisition Means) 76... Cooling Circuit ECU (Cooling Output Control Means) 81... First Battery Sensor Unit (Temperature Acquisition Means, Allowable Output Upper Limit Acquisition Means) 82... Second Battery Sensor Unit (Temperature Acquisition Means, Allowable Output Upper Limit Acquisition Means) 9... Cooling Circuit 91... First Cooling Device 92... Second Cooling Device

Claims

1. a first power storage device, a second power storage device, a load circuit including a rotating electrical machine, a power circuit connecting the first and second power storage devices and the load circuit, a power control means for controlling the output power of the first and second power storage devices by operating the power circuit, and comprising a power supply system, a temperature acquisition means for acquiring a first temperature which is the temperature of the first power storage device and a second temperature which is the temperature of the second power storage device, a permissible output upper limit acquisition means for acquiring a first permissible output upper limit for the output power of the first power storage device and a second permissible output upper limit for the output power of the second power storage device, when the first temperature is equal to or higher than a first temperature reference value and the second temperature is lower than a second temperature reference value, the power control means sets the control mode to a first priority output mode in which the output power of the first power storage device is increased to the first permissible output upper limit with priority over the second power storage device; and when the first temperature is lower than the first temperature reference value and the second temperature is equal to or higher than the second temperature reference value, the power control means sets the control mode to a second priority output mode in which the output power of the second power storage device is increased to the second permissible output upper limit with priority over the first power storage device. The power supply system is characterized by this.

2. a cooling circuit for cooling the first power storage device and the second power storage device, a cooling output control means for controlling a first cooling output for the first power storage device by the cooling circuit and a second cooling output for the second power storage device by the cooling circuit, when the first temperature is lower than the first temperature reference value, the cooling output control means reduces the first cooling output compared to when the first temperature is equal to or higher than the first temperature reference value; and when the second temperature is lower than the second temperature reference value, the cooling output control means reduces the second cooling output compared to when the second temperature is equal to or higher than the second temperature reference value. The power supply system according to claim 1 is characterized by this.

3. further comprising a loss acquisition means for acquiring a first loss occurring in the first power storage device and the power circuit when the control mode is the first priority output mode and a second loss occurring in the second power storage device and the power circuit when the control mode is the second priority output mode, When the first temperature is equal to or higher than the first temperature reference value and the second temperature is equal to or higher than the second temperature reference value, the power control means sets the control mode to the second priority output mode when the first loss is greater than the second loss, and sets the control mode to the first priority output mode when the second loss is greater than the first loss. The power supply system according to claim 2, characterized in that.

4. A first power circuit having the first power storage device; A second power circuit having the second power storage device; A voltage converter that converts a voltage between the first power circuit and the second power circuit; A power converter that connects the first power circuit and the rotating electrical machine, further comprising: When the first temperature is equal to or higher than the first temperature reference value and the second temperature is equal to or higher than the second temperature reference value, the power control means sets the control mode to the first priority output mode. The power supply system according to claim 2, characterized in that.

5. The heat capacity of the second power storage device is smaller than the heat capacity of the first power storage device, When the first temperature is less than the first temperature reference value and the second temperature is less than the second temperature reference value, the power control means sets the control mode to the second priority output mode. The power supply system according to any one of claims 2 to 4, characterized in that.

6. A first power storage device, A second power storage device, A load circuit including a rotating electrical machine, A power circuit that connects the first and second power storage devices and the load circuit, Power control means for controlling the output power of the first and second power storage devices by operating the power circuit, A cooling circuit for cooling the first power storage device and the second power storage device, A power supply system comprising cooling output control means for controlling a first cooling output to the first power storage device by the cooling circuit and a second cooling output to the second power storage device by the cooling circuit, Temperature acquisition means for acquiring a first temperature that is the temperature of the first power storage device and a second temperature that is the temperature of the second power storage device, And allowable output upper limit acquisition means for acquiring a first allowable output upper limit for the output power of the first power storage device and a second allowable output upper limit for the output power of the second power storage device. The power control means switches the control mode based on the first and second temperatures to a first priority output mode in which the output power of the first power storage device is increased to the first allowable output upper limit with priority over the second power storage device or a second priority output mode in which the output power of the second power storage device is increased to the second allowable output upper limit with priority over the first power storage device. The cooling output control means reduces the first cooling output when the first temperature is less than the first temperature reference value compared to when the first temperature is equal to or higher than the first temperature reference value, and reduces the second cooling output when the second temperature is less than the second temperature reference value compared to when the second temperature is equal to or higher than the second temperature reference value. A power supply system characterized by this.

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