Power System

Abstract

The present invention provides a power supply system for a vehicle that can use two batteries to travel in multiple operating modes, and the power supply system is capable of maintaining each battery in a state suitable for the operating mode. The vehicle power supply system includes: a management ECU that controls the output power of a first battery and a second battery in normal mode or output priority mode; a first cooling device that cools the first battery; a second cooling device that cools the second battery; and a cooling circuit ECU that controls the first cooling output of the first cooling device and the second cooling output of the second cooling device. When the operating mode of the management ECU is output priority mode and the first battery has cooling margin, the cooling circuit ECU increases the first cooling output compared to when the operating mode is normal mode. When the operating mode is output priority mode and the second battery has cooling margin, the cooling circuit ECU increases the second cooling output compared to when the operating mode is normal mode.

Description

Technical Field

[0001] The present invention relates to a power supply system, and more particularly, to a power supply system including two power storage devices and a cooling device for the power storage devices. Background Art

[0002] In recent years, the development of electric vehicles has been booming, including electric transportation equipment equipped with a drive motor as a power source, and hybrid vehicles equipped with a drive motor and an internal combustion engine as power sources. These electric vehicles also include electrical storage devices (such as batteries and capacitors) to supply energy to the drive motor. Furthermore, electric vehicles equipped with multiple electrical storage devices with different characteristics have also been developed in recent years.

[0003] For example, Patent Document 1 shows a power supply system for an electric vehicle in which a capacity-type battery and an output-type battery are connected to a drive motor via a power circuit. This power supply system, equipped with two batteries having different characteristics, allows the vehicle to travel in various operating modes, such as normal mode (in which the vehicle travels solely on power output from the capacity-type battery) or output-priority mode (in which the vehicle compensates for a high output shortfall caused by power output from the capacity-type battery alone).

[0004] Prior art literature

[0005] Patent Literature

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-70078 Summary of the Invention

[0007] Technical problems to be solved by the present invention

[0008] However, charging and discharging batteries at high temperatures can accelerate their degradation. Therefore, as shown in Patent Document 1, most power supply systems incorporate cooling circuits to cool the batteries and maintain their temperature at an appropriate level. However, for power supply systems capable of operating in multiple modes, there has been insufficient research into how to tailor cooling methods to each operating mode.

[0009] An object of the present invention is to provide a power supply system that can drive a rotating electric machine in a plurality of operation modes using two power storage devices, and the power supply system can maintain each power storage device in a state suitable for the operation mode.

[0010] Solutions to the Problem

[0011] (1) The power supply system of the present invention (e.g., power supply system 1 described later) includes: a first power storage device (e.g., first battery B1 described later); a second power storage device (e.g., second battery B2 described later); a load circuit (e.g., load circuit 4 described later) including a rotating electrical machine (e.g., drive motor M described later); a power circuit (e.g., first power circuit 2 and second power circuit 3 described later) connecting the first power storage device and the second power storage device to the load circuit; and a power control unit (e.g., management electronic control unit described later). The first power storage device and the second power storage device are controlled by a first cooling device (e.g., a first cooling device 91 to be described later) to cool the first power storage device; the second cooling device (e.g., a second cooling device 92 to be described later) to cool the second power storage device; a cooling output control unit (e.g., a cooling circuit ECU 76 to be described later) to control the first cooling output of the first cooling device and the second cooling output of the second cooling device; and a cooling margin acquisition unit (e.g., a cooling circuit ECU 76 to be described later) to acquire the cooling margin according to the first cooling device. The power supply system comprises a first cooling margin (for example, the first cooling margin PC1_mar described later) that increases or decreases according to the difference between the first maximum cooling output and the first cooling output, and a second cooling margin (for example, the second cooling margin PC2_mar described later) that increases or decreases according to the difference between the second maximum cooling output of the second cooling device and the second cooling output. The power supply system is characterized in that: when the operation mode of the power control unit is the output priority mode and the first cooling margin is above the first cooling margin threshold, the cooling output control unit makes the first cooling output greater than the case where the operation mode is the normal mode; and when the operation mode is the output priority mode and the second cooling margin is above the second cooling margin threshold, the cooling output control unit makes the second cooling output greater than the case where the operation mode is the normal mode.

[0012] (2) In this case, the power supply system preferably further includes: a temperature acquisition unit (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) for acquiring a first temperature of the first power storage device and a second temperature of the second power storage device; and a temperature margin acquisition unit (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) for acquiring a first temperature margin (for example, the first temperature margin T1_mar described later) that increases or decreases according to the difference between the first upper limit temperature of the first power storage device and the first temperature, and a second temperature margin (for example, the second temperature margin T2_mar described later) that increases or decreases according to the difference between the second upper limit temperature of the second power storage device and the second temperature, and the power control unit controls the first output power and the second output power based on the first cooling margin and the second cooling margin and the first temperature margin and the second temperature margin.

[0013] (3) In this case, it is preferred that when the first cooling margin is greater than the first cooling margin threshold and the first temperature margin is greater than the first temperature margin threshold, the power control unit makes the first output power greater than the case where the first cooling margin or the first temperature margin is less than the first cooling margin threshold or the first temperature margin threshold, and when the second cooling margin is greater than the second cooling margin threshold and the second temperature margin is greater than the second temperature margin threshold, the power control unit makes the second output power greater than the case where the second cooling margin or the second temperature margin is less than the second cooling margin threshold or the second temperature margin threshold.

[0014] (4) In this case, it is preferred that when the first cooling margin is less than the first cooling margin threshold, the cooling output control unit increases the first cooling output to the first maximum cooling output; when the second cooling margin is less than the second cooling margin threshold, the cooling output control unit increases the second cooling output to the second maximum cooling output; when the first cooling margin is less than the first cooling margin threshold and the first temperature margin is less than the first temperature margin threshold, the power control unit makes the first output power smaller than when the first cooling margin or the first temperature margin is greater than the first cooling margin threshold or the first temperature margin threshold; when the second cooling margin is less than the second cooling margin threshold and the second temperature margin is less than the second temperature margin threshold, the power control unit makes the second output power smaller than when the second cooling margin or the second temperature margin is greater than the second cooling margin threshold or the second temperature margin threshold.

[0015] (5) In this case, it is preferred that the temperature margin acquisition unit calculates the first temperature margin based on a first temperature difference between the first upper limit temperature and the first temperature and a first heat capacity of the first power storage device, and calculates the second temperature margin based on a second temperature difference between the second upper limit temperature and the second temperature and a second heat capacity of the second power storage device.

[0016] (6) In this case, preferably, when the first cooling output and the second cooling output are respectively greater than the first cooling margin threshold and the second cooling margin threshold, and the first temperature margin and the second temperature margin are respectively greater than the first temperature margin threshold and the second temperature margin threshold, the power control unit gives priority to outputting the power storage device having the larger temperature margin of either the first temperature margin or the second temperature margin.

[0017] (7) In this case, it is preferred that the heat capacity of the first power storage device is greater than the heat capacity of the second power storage device, and when the first cooling margin and the second cooling margin are respectively greater than the first cooling margin threshold and the second cooling margin threshold, and the first temperature margin and the second temperature margin are respectively greater than the first temperature margin threshold and the second temperature margin threshold, the power control unit causes the first power storage device to output with higher priority than the second power storage device.

[0018] Effects of the Invention

[0019] (1) In the present invention, the power control unit controls the output power of the first and second power storage devices in normal mode or in an output priority mode that allows a higher output than normal mode. The cooling output control unit controls the first and second cooling outputs of the first and second cooling devices. The cooling margin acquisition unit acquires the first and second cooling margins that increase or decrease based on the difference between the first and second maximum cooling outputs of the first and second cooling devices and the first and second cooling outputs. Furthermore, when the operating mode is output priority mode and the first cooling margin is greater than a first cooling margin threshold, the cooling output control unit increases the first cooling output compared to when the operating mode is normal mode. When the operating mode is output priority mode and the second cooling margin is greater than a second cooling margin threshold, the cooling output control unit increases the second cooling output compared to when the operating mode is normal mode. Here, when the operating mode is output priority mode, the output of each power storage device increases, and therefore, the amount of heat generated also tends to increase. Therefore, in the present invention, when the cooling capacity of each cooling device is large—that is, when there is room for increased cooling output—the cooling output is increased in anticipation of the increase in heat generated by each power storage device. This allows each power storage device to be maintained at an appropriate temperature in output priority mode, enabling rapid output increases based on demand. Furthermore, this reduces the likelihood of power storage devices being restricted due to excessive temperature increases.

[0020] (2) In the present invention, the power control unit controls the first and second output powers based on the first and second cooling margins and the first and second temperature margins. This allows the first and second output powers to be controlled to appropriate levels, anticipating the potential for increase in cooling output of each cooling device.

[0021] (3) In the present invention, when the operating mode is the output mode and each cooling margin is greater than each cooling margin threshold, as described above, the cooling output control unit increases each cooling output compared to the normal mode. Furthermore, when each cooling margin is greater than each cooling margin threshold and each temperature margin is greater than each temperature margin threshold, the power control unit increases each output power compared to when each cooling margin or each temperature margin is less than each cooling margin threshold or each temperature margin threshold. This increases the output power of each power storage device while suppressing excessive temperature increases in each power storage device.

[0022] (4) In the present invention, when each cooling margin is less than each cooling margin threshold, the cooling output control unit increases each cooling output to each maximum cooling output. When each cooling margin is less than each cooling margin threshold and each temperature margin is less than each temperature margin threshold, the power control unit reduces each output power compared to when each cooling margin or each temperature margin is equal to or greater than each cooling margin threshold. This promotes a decrease in the temperature of each power storage device, allowing the output power of each power storage device to be increased again.

[0023] (5) In the present invention, the temperature margin unit calculates each temperature margin based on the temperature differences and the heat capacity of each power storage device. This allows the power control unit to prevent excessive temperature increases in each power storage device while taking into account the heat capacity of each power storage device and to control the output power of each power storage device to an appropriate level.

[0024] (6) In the present invention, when each cooling margin is greater than or equal to each cooling margin threshold and each temperature margin is greater than or equal to each temperature margin threshold, the power control unit prioritizes output to the power storage device having the greater temperature margin, as calculated by taking into account the heat capacity as described above. This prevents excessive temperature increases in each power storage device and allows the output power of each power storage device to be controlled to an appropriate level.

[0025] (7) In the present invention, when each cooling margin is greater than or equal to each cooling margin threshold and each temperature margin is greater than or equal to each temperature margin threshold, the power control unit prioritizes output from the first power storage device having a larger heat capacity over the second power storage device having a smaller heat capacity. This prevents excessive temperature increases in each power storage device and maintains the output power of each power storage device at an appropriate level. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a diagram showing the configuration of a vehicle equipped with the power supply system according to the first embodiment of the present invention.

[0027] Figure 2 This is a diagram showing an example of a circuit configuration of a voltage converter.

[0028] Figure 3 This is a diagram showing an example of a circuit configuration of a cooling circuit.

[0029] Figure 4 This is a flowchart showing the specific procedure of the power management process.

[0030] Figure 5A This is a flowchart (part 1) showing the procedure for calculating target converter-passed power and target inverter-passed power in the output priority mode.

[0031] Figure 5B This is a flowchart (part 2) showing the procedure for calculating the target converter pass-through power and the target inverter pass-through power in the output priority mode.

[0032] Figure 6 This is a diagram showing an example of an operation table that determines the output and cooling method of the battery based on the temperature margin and the cooling margin.

[0033] Figure 7 This is a diagram showing an example of an operation table of the power supply system according to the second embodiment of the present invention. DETAILED DESCRIPTION

[0034] <First embodiment>

[0035] Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

[0036] Figure 1 This figure shows the structure of a four-wheeled electric vehicle V (hereinafter referred to simply as "vehicle") equipped with the power supply system 1 according to this embodiment. Furthermore, while this embodiment describes the case where the power supply system 1 is installed on the four-wheeled vehicle V, the present invention is not limited to this embodiment. The power supply system of the present invention is not limited to four-wheeled vehicles V; it can also be applied to mobile objects such as saddle-type vehicles, ships, robots, and drones that utilize the thrust generated by rotating electric machines, or to stationary power sources.

[0037] A vehicle V includes drive wheels W, a drive motor M serving as a rotating electrical machine connected to the drive wheels W, and a power supply system 1 that exchanges electric power between the drive motor M and a first battery B1 and a second battery B2, described later. While this embodiment describes an example in which the vehicle V is accelerated and decelerated primarily using the power generated by the drive motor M, the present invention is not limited thereto. The vehicle V may also be a so-called hybrid vehicle equipped with both the drive motor M and an engine as power sources.

[0038] The drive motor M is connected to the drive wheels W via a transmission mechanism (not shown). Three-phase AC power is supplied to the drive motor M from the power supply system 1, and the torque generated by the drive motor M is transmitted to the drive wheels W via the transmission mechanism (not shown), rotating the drive wheels W and causing the vehicle V to travel. Furthermore, when the vehicle V decelerates, the drive motor M functions as a generator, generating regenerative power and applying regenerative braking torque corresponding to the amount of this regenerative power to the drive wheels W. The regenerative power generated by the drive motor M appropriately charges the batteries B1 and B2 of the power supply system 1.

[0039] The power supply 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 and second power circuits 2 and 3; a load circuit 4 having various electrical loads including a drive motor M; a cooling circuit 9 for cooling the first and second batteries B1 and B2; and an electronic control unit 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. The electronic control unit 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.

[0040] First battery B1 is a secondary battery capable of both discharge and charge. Discharge converts chemical energy into electrical energy, while charge converts electrical energy into chemical energy. While the following description uses a so-called lithium-ion battery as first battery B1, the present invention is not limited to this. Such so-called lithium-ion batteries are charged and discharged by the movement of lithium ions between electrodes.

[0041] A first battery sensor unit 81 is provided for the first battery B1. This unit is used to estimate the internal state of the first battery B1. The first battery sensor unit 81 is composed of multiple sensors that detect physical quantities necessary for obtaining the first battery ECU 74's information about the remaining charge of the first battery B1, such as the charge rate (battery charge level expressed as a percentage) and temperature, and transmits signals corresponding to the detected values to the first battery ECU 74. More specifically, the first battery sensor unit 81 includes 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.

[0042] Second battery B2 is a secondary battery capable of both discharge and charge. Discharge refers to converting chemical energy into electrical energy, while charge refers to converting electrical energy into chemical energy. While the following describes the use of a so-called lithium-ion secondary battery as second battery B2, the present invention is not limited to this. Such lithium-ion secondary batteries are charged and discharged by the movement of lithium ions between electrodes. For example, a capacitor may also be used as second battery B2.

[0043] A second battery sensor unit 82 is provided for the second battery B2, which is used to estimate the internal state of the second battery B2. The second battery sensor unit 82 is composed of multiple sensors that detect physical quantities necessary for obtaining the second battery B2's charge rate and temperature in the second battery ECU 75 and transmit signals corresponding to the detected values to the second battery ECU 75. More specifically, the second battery sensor unit 82 includes 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.

[0044] Here, the characteristics of the first battery B1 and the characteristics of the second battery B2 are compared.

[0045] 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. In other words, the first battery B1 is superior to the second battery B2 in terms of energy weight density. Furthermore, energy weight density refers to the amount of electricity per unit weight [Wh / kg], while output weight density refers to the amount of electricity per unit weight [W / kg]. Therefore, the first battery B1, which has an excellent energy weight density, is a capacity-type battery whose primary purpose is high capacity, while the second battery B2, which has an excellent output weight density, is an output-type battery whose primary purpose is high output. Therefore, in the power supply system 1, the first battery B1 is used as the main power source, and the second battery B2 is used as a secondary power source to supplement the first battery B1. Furthermore, the heat capacity of the first battery B1 is greater than that of the second battery B2. Therefore, the temperature of the first battery B1 rises more slowly than that of the second battery B2.

[0046] The first power circuit 2 includes: a first battery B1; first power lines 21p and 21n, connecting the positive and negative poles of the above-mentioned first battery B1 with the positive terminal and negative terminal on the high-voltage side of the voltage converter 5; and a positive contactor 22p and a negative contactor 22n, which are arranged on the above-mentioned first power lines 21p and 21n.

[0047] Contactors 22p and 22n are normally open contactors. When no external command signal is input, they open, thereby severing the conduction between the two electrodes of first battery B1 and first power lines 21p and 21n. When a command signal is input, they close, thereby connecting first battery B1 to first power lines 21p and 21n. These contactors 22p and 22n open and close in response to command signals sent from first battery ECU 74. Furthermore, positive contactor 22p is a precharge contactor equipped with a precharge resistor, which mitigates inrush current flowing into multiple smoothing capacitors provided in first power circuit 2 or load circuit 4.

[0048] The second power circuit 3 includes: a second battery B2; second power lines 31p and 31n, connecting the positive and negative poles of the above-mentioned second battery B2 with the positive terminal and negative terminal on the low-voltage side of the voltage converter 5; a positive contactor 32p and a negative contactor 32n, arranged on the above-mentioned second power lines 31p and 31n; and a current sensor 33, arranged on the second power line 31p.

[0049] Contactors 32p and 32n are normally open contactors. When no external command signal is input, they open, thereby severing the conduction between the two electrodes of second battery B2 and second power lines 31p and 31n. When a command signal is input, they close, thereby connecting second battery B2 to second power lines 31p and 31n. These contactors 32p and 32n open and close in response to command signals sent from the second battery ECU 75. Furthermore, the positive contactor 32p is a precharge contactor equipped with a precharge resistor, which mitigates inrush current flowing into the multiple smoothing capacitors provided in the first power circuit 2 or the load circuit 4.

[0050] Current sensor 33 transmits a detection signal corresponding to the current flowing through second power line 31p, that is, the current flowing through voltage converter 5, to converter ECU 73. Furthermore, in this embodiment, the direction of the current flowing is defined as positive, with the direction from second power circuit 3 toward first power circuit 2 being positive, and negative, with the direction from first power circuit 2 toward second power circuit 3 being negative. That is, the current flowing through voltage converter 5 becomes positive when second battery B2 is discharging, and becomes negative when second battery B2 is charging.

[0051] The load circuit 4 includes a vehicle auxiliary device 42 , a power converter 43 connected to the drive motor M, and load power lines 41 p and 41 n connecting the vehicle auxiliary device 42 and the power converter 43 to the first power circuit 2 .

[0052] The vehicle auxiliary equipment 42 is composed of multiple electrical loads, including a battery heater, an air compressor, a direct current (DC) converter, and an onboard charger. The vehicle auxiliary equipment 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 regarding the operating status of the various electrical loads that make up the vehicle auxiliary equipment 42 is transmitted, for example, to the management ECU 71.

[0053] 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 PWM inverter that includes a bridge circuit formed by bridging multiple switching elements (e.g., insulated gate bipolar transistors (IGBTs)) and utilizes pulse width modulation. It has the function of converting DC power into AC power. The power converter 43 is connected to the first power lines 21p and 21n on its DC input and output sides, and to the U-phase, V-phase, and W-phase coils of the drive motor M on its AC input and output sides. The power converter 43 drives the switching elements of each phase on / off according to the gate drive signal generated by the unillustrated gate drive circuit of the motor ECU 72 at a specified timing, 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.

[0054] The voltage converter 5 connects the first power circuit 2 and the second power circuit 3, and converts the voltage between the two circuits 2 and 3. A known boost circuit is used for the voltage converter 5.

[0055] Figure 2This diagram shows an example of the circuit configuration of voltage converter 5. Voltage converter 5 connects first power lines 21p and 21n connected to first battery B1 and second power lines 31p and 31n connected to second battery B2, converting the voltage between these first and second power lines 21p and 21n. 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 terminals 56p and 56n, high-voltage terminals 57p and 57n, and a smoothing capacitor (not shown).

[0056] Low-voltage terminals 56p and 56n are connected to second power lines 31p and 31n, and high-voltage terminals 57p and 57n are connected to first power lines 21p and 21n. Negative bus 55 is wiring that connects low-voltage terminal 56n and high-voltage terminal 57n.

[0057] One end of the first reactor L1 is connected to the low-voltage 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 freewheeling diode connected to the power switching element. The high-arm element 53H and the low-arm element 53L are connected in series, sequentially, between the high-voltage terminal 57p and the negative bus 55.

[0058] The collector of the power switching element of the first high-arm element 53H is connected to the high-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 of the first low-arm element 53L is connected to the negative bus 55. The forward direction of the freewheeling diode provided in the first high-arm element 53H is from the first reactor L1 toward the high-side terminal 57p. Furthermore, the forward direction of the freewheeling diode provided in the first low-arm element 53L is from the negative bus 55 toward the first reactor L1.

[0059] One end of the second reactor L2 is connected to the low-voltage 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 freewheeling 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 terminal 57p and the negative bus 55.

[0060] The collector of the power switching element of the second high-arm element 54H is connected to the high-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 forward direction of the freewheeling diode provided in the second high-arm element 54H is from the second reactor L2 toward the high-side terminal 57p. Furthermore, 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.

[0061] The voltage converter 5 alternately drives 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 on / off according to a gate drive signal generated from an unillustrated gate drive circuit of the converter ECU 73 at a prescribed timing, thereby converting the voltage between the first power lines 21p, 21n and the second power lines 31p, 31n.

[0062] The static voltage of second battery B2 is generally maintained lower than that of first battery B1. Therefore, the voltage of first power lines 21p, 21n is generally higher than the voltage of second power lines 31p, 31n. Therefore, when driving motor M using both the power output from first battery B1 and the power output from second battery B2, converter ECU 73 operates voltage converter 5 to perform its voltage boosting function. The voltage boosting function boosts the power flowing in second power lines 31p, 31n, connected to low-voltage terminals 56p, 56n, and outputs it to first power lines 21p, 21n, connected to high-voltage terminals 57p, 57n. This causes positive current to flow from second power lines 31p, 31n to first power lines 21p, 21n. Furthermore, when suppressing discharge of second battery B2 and driving motor M using only the power output from first battery B1, converter ECU 73 disconnects voltage converter 5 so that current does not flow from first power lines 21p, 21n to second power lines 31p, 31n.

[0063] Furthermore, when charging first battery B1 or second battery B2 using regenerative electric power output from drive motor M to first power lines 21p, 21n during deceleration, converter ECU 73 operates voltage converter 5 to perform its voltage step-down function. The voltage step-down function steps down the voltage of electric power flowing through first power lines 21p, 21n connected to high-voltage terminals 57p, 57n and outputs it to second power lines 31p, 31n connected to low-voltage terminals 56p, 56n. This causes a negative current to flow from first power lines 21p, 21n to second power lines 31p, 31n.

[0064] Back to Figure 1 The first battery ECU 74 is a computer primarily responsible for monitoring the state of the first battery B1 and operating the contactors 22p and 22n of the first power circuit 2. Using a known algorithm using detection values transmitted from the first battery sensor unit 81, the first battery ECU 74 calculates various parameters indicating the internal state of the first battery B1. More specifically, it calculates 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 quiescent voltage of the first battery B1, the closed circuit voltage of the first battery B1, a first output upper limit corresponding to the upper limit of the power outputtable from the first battery B1, a first state of charge (SOC) corresponding to the charge rate of the first battery B1, and a first temperature margin of the first battery B1. Information regarding the parameters indicating the internal state of the first battery B1 obtained by the first battery ECU 74 is transmitted, for example, to the management ECU 71.

[0065] Here, the first temperature margin is a parameter indicating the margin associated with the temperature of the first battery B1. More specifically, the first temperature margin is defined as a parameter that increases or decreases depending on the difference between the first battery upper limit temperature (the upper limit of the operating temperature range of the first battery B1) and the first battery temperature. The first battery ECU 74 calculates the first temperature margin by subtracting the first battery temperature from a predetermined first battery upper limit temperature. Therefore, as the first battery temperature rises and approaches the first battery upper limit temperature, the first temperature margin decreases.

[0066] The second battery ECU 75 is a computer primarily responsible for monitoring the state of the second battery B2 and operating the contactors 32p and 32n of the second power circuit 3. Based on a known algorithm using the detection values transmitted from the second battery sensor unit 82, the second battery ECU 75 calculates various parameters indicating the internal state of the second battery B2. More specifically, it calculates 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 output upper limit corresponding to the upper limit of the power that can be output from the second battery B2, the second state of charge corresponding to the charge rate of the second battery B2, and the second temperature margin of the second battery B2. Information regarding the parameters indicating the internal state of the second battery B2 obtained by the second battery ECU 75 is transmitted, for example, to the management ECU 71.

[0067] Here, the second temperature margin is a parameter indicating the margin associated with the temperature of the second battery B2. More specifically, the second temperature margin is defined as a parameter that increases or decreases depending on the difference between the second battery upper limit temperature (the upper limit of the operating temperature range of the second battery B2) and the second battery temperature. The second battery ECU 75 calculates the second temperature margin by subtracting the second battery temperature from a predetermined second battery upper limit temperature. Therefore, as the second battery temperature rises and approaches the second battery upper limit temperature, the second temperature margin decreases.

[0068] Furthermore, charging and discharging a high-temperature battery may accelerate its degradation. Therefore, the first output upper limit of the first battery B1 and the second output upper limit of the second battery B2 are set to decrease as their respective temperatures increase.

[0069] The management ECU 71 is a computer that mainly manages the flow of power in the entire power supply system 1. The management ECU 71 refers to Figure 4 The power management processing described above generates an inverter power instruction signal and a converter power instruction signal, wherein the inverter power instruction signal is equivalent to an instruction for the power passing through the power converter 43, i.e., the inverter power instruction signal, and the converter power instruction signal is equivalent to an instruction for the power passing through the voltage converter 5, i.e., the converter power instruction signal.

[0070] The motor ECU 72 is a computer that mainly operates the power converter 43 and controls the flow of power between the first power circuit 2 and the drive motor M, that is, the flow of inverter-through power. Furthermore, in the following, when power flows from the first power circuit 2 to the drive motor M, that is, when the drive motor M is accelerating, the inverter-through power is set to positive. In addition, when power flows from the drive motor M to the first power circuit 2, that is, when the drive motor M is regenerating, the inverter-through power is set to negative. The motor ECU 72 operates the power converter 43 according to the inverter-through power instruction signal sent from the management ECU 71, so that the inverter-through power corresponding to the instruction passes through the power converter 43, in other words, so that the drive motor M generates a torque corresponding to the inverter-through power.

[0071] The converter ECU 73 is a computer that primarily operates the voltage converter 5 and controls the flow of power between the first power circuit 2 and the second power circuit 3, namely, the flow of converter pass power. Hereinafter, when power flows from the second power circuit 3 to the first power circuit 2, that is, when power is discharged from the second battery B2 and supplied to the first power circuit 2, the converter pass power is set to positive. Furthermore, when power flows from the first power circuit 2 to the second power circuit 3, that is, when second battery B2 is charged with power from the first power circuit 2, the converter pass power is set to negative. Based on a converter pass power command signal transmitted from the management ECU 71, the converter ECU 73 operates the voltage converter 5 so that the converter pass power corresponding to the command passes through the voltage converter 5. More specifically, based on the converter pass power command signal, the converter ECU 73 calculates a target current for the current flowing through the voltage converter 5 and, using a known feedback control algorithm, operates the voltage converter 5 so that the current flowing through the voltage converter 5 (hereinafter also referred to as the "actual current flowing through") detected by the current sensor 33 reaches the target current.

[0072] As described above, in power supply system 1, the management ECU 71, motor ECU 72, and converter ECU 73 operate the voltage converter 5 and power converter 43, controlling the power passing through the voltage converter 5 or power converter 43. This controls the output power of first battery B1 (i.e., first battery output power) and the output power of second battery B2 (i.e., second battery output power). Therefore, in this embodiment, the power control unit that controls the first and second battery output powers is comprised of the management ECU 71, motor ECU 72, and converter ECU 73. More specifically, the power control unit controls the converter power passing through to P2 and the inverter power passing through to P1+P2, thereby controlling the first and second battery output powers to P1 and P2, respectively.

[0073] Figure 3 1 is a diagram showing the circuit configuration of the cooling circuit 9 .

[0074] Cooling circuit 9 includes a first cooling device 91 that cools first battery B1 , a second cooling device 92 that cools second battery B2 , and a third cooling device 93 that cools voltage converter 5 and power converter 43 .

[0075] The first cooling device 91 includes: a first cooling water circulation path 911, including a cooling water flow path formed in the battery case (battery case) accommodating the first battery B1; a first heat exchanger 912 and a first cooling water pump (pump) 913, which are arranged in the above-mentioned first cooling water circulation path 911; and a heating device 94, which is connected to the first cooling water circulation path 911.

[0076] The first cooling water pump 913 rotates in response to commands input from the cooling circuit ECU 76, circulating the cooling water within the first cooling water circulation path 911. The first heat exchanger 912 cools the cooling water, which has been 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 cooling fan that rotates in response to commands input from the cooling circuit ECU 76.

[0077] The heating device 94 includes: a bypass path 941, which 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, which are arranged in the bypass path 941; and three-way valves 944 and 945, which are arranged in the connection part between the two ends of the bypass path 941 and the first cooling water circulation path 911.

[0078] The heating pump 943 rotates according to a command input from the cooling circuit ECU 76 to circulate the cooling water through the first cooling water circulation path 911 and the bypass path 941. The heater 942 generates heat by consuming power supplied from a battery (not shown), thereby increasing the temperature of the cooling water flowing through the bypass path 941.

[0079] Three-way valves 944 and 945 open and close in response to commands from the cooling circuit ECU 76, switching the flow path of the cooling water between the first heat exchanger 912 side and the heater 942 side. Thus, the first cooling device 91 has both a cooling function and a heating function. The cooling function cools the first battery B1 by circulating the cooling water cooled by the first heat exchanger 912, and the heating function heats the first battery B1 by circulating the cooling water heated by the heater 942.

[0080] The cooling circuit ECU 76 operates the first heat exchanger 912, the first cooling water pump 913, the heater 942, the warming pump 943, and the three-way valves 944 and 945 based on the first battery temperature transmitted from the first battery ECU 74, the detection value of the first cooling water temperature sensor (not shown) detecting the temperature of the cooling water flowing through the first cooling water circulation path 911, the detection value of the outside air temperature sensor (not shown), and instructions from the management ECU 71. This controls the first cooling output of the first cooling device 91 for the first battery B1. The first cooling output is a parameter that increases or decreases depending on the cooling performance of the first cooling device 91 for the first battery B1, and is, for example, the rotational speed of a cooling fan provided in the first heat exchanger 912.

[0081] Furthermore, the cooling circuit ECU 76 calculates a first cooling margin corresponding to the margin for cooling the first battery B1 by the first cooling device 91 and transmits this first cooling margin to the management ECU 71. More specifically, the cooling circuit ECU 76 calculates the first cooling margin as the value obtained by subtracting the current first cooling output from the first maximum cooling output (e.g., the maximum speed of the cooling fan), which corresponds to the maximum value of the first cooling output of the first cooling device 91. In other words, this first cooling margin increases or decreases based on the difference between the first maximum cooling output and the first cooling output. The specific sequence in which the cooling circuit ECU 76 controls the first cooling output will be described later.

[0082] The second cooling device 92 includes, for example, a cooling fan that supplies external air into the battery case housing the second battery B2. The second cooling device 92 rotates in response to a command from the cooling circuit ECU 76 to supply external air into the battery case of the second battery B2, thereby cooling the second battery B2.

[0083] The cooling circuit ECU 76 operates the second cooling device 92 based on the second battery temperature sent from the second battery ECU 75, the detection value of the outside air temperature sensor, and instructions from the management ECU 71, thereby controlling the second cooling output of the second cooling device 92 for the second battery B2. Here, the second cooling output is a parameter that increases or decreases according to the cooling performance of the second cooling device 92 for the second battery B2, and is, for example, the rotational speed of the cooling fan of the second cooling device 92.

[0084] The cooling circuit ECU 76 also calculates a second cooling margin corresponding to the margin for cooling the second battery B2 by the second cooling device 92, and transmits this second cooling margin to the management ECU 71. More specifically, the cooling circuit ECU 76 calculates the second cooling margin as the value obtained by subtracting the current second cooling output from the second maximum cooling output (e.g., the maximum speed of the cooling fan), which corresponds to the maximum value of the second cooling output of the second cooling device 92. In other words, this second cooling margin increases or decreases based on the difference between the second maximum cooling output and the second cooling output. The specific sequence in which the cooling circuit ECU 76 controls the second cooling output will be described later.

[0085] The third cooling device 93 includes a third cooling water circulation path 931 including a cooling water flow path formed in a housing in which the voltage converter 5 and the power converter 43 are installed, and a third heat exchanger 932 and a third cooling water pump 933 installed in the third cooling water circulation path 931 .

[0086] Third cooling water pump 933 rotates in response to commands input from cooling circuit ECU 76, circulating cooling water within third cooling water circulation path 931. Third heat exchanger 932 cools the cooling water, which has been heated by heat exchange with voltage converter 5 and power converter 43, by promoting heat exchange between the cooling water circulating within third cooling water circulation path 931 and the outside air. Third heat exchanger 932 includes a cooling fan that rotates in response to commands input from cooling circuit ECU 76.

[0087] 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 instruction from the management ECU 71, thereby controlling the third cooling output corresponding to the cooling performance of the third cooling device 93 for the voltage converter 5 or the power converter 43.

[0088] 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 and other components are water-cooled using heat exchange with cooling water, while 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 using heat exchange with the 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, and the third cooling device 93 may be air-cooled. Furthermore, in this embodiment, the cooling water circulation path for cooling the first battery B1 and the cooling water circulation path for cooling the voltage converter 5 or the power converter 43 are separate systems, but the present invention is not limited to this. Either or both of the voltage converter 5 and the power converter 43 may be cooled using the cooling water used to cool the first battery B1.

[0089] Figure 4 This is a flowchart showing the specific sequence of the power management process. This power management process is repeatedly executed in a predetermined cycle in the management ECU 71, starting when the driver turns on a start switch (not shown) to start the vehicle V and the power supply system 1, and ending when the driver turns off the start switch again to stop the vehicle V and the power supply system 1.

[0090] First, in step S1, the management ECU 71 controls the accelerator pedal, brake pedal, and other pedals (see Figure 1 ) operation amount, calculates the driver's required driving torque, and converts the required driving torque into electric power, thereby calculating the required inverter power Pmot_d equivalent to the required output of the drive motor M in the power converter 43, and transferring to step S2.

[0091] Next, in step S2, the management ECU 71 determines whether the required inverter power passing through Pmot_d calculated in step S1 is equal to or greater than the high output threshold value Phigh. If the determination result in step S2 is NO, the management ECU 71 proceeds to step S3. If the determination result in step S2 is YES, the management ECU 71 proceeds to step S4.

[0092] Next, in step S3, the management ECU 71 calculates a target converter power Pcnv_cmd, corresponding to the target converter power, and a target inverter power Pmot_cmd, corresponding to the target inverter power, in normal mode, and then proceeds to step S7. In normal mode, the management ECU 71 calculates the target converter power Pcnv_cmd and target inverter power Pmot_cmd so that power is input to and output from the first battery B1 and the second battery B2 according to a target ratio calculated based on a predetermined algorithm. Furthermore, in normal mode, the management ECU 71 limits the target inverter power Pmot_cmd to below the high output threshold Phigh.

[0093] Next, in step S7, management ECU 71 generates a converter power command signal corresponding to target converter power Pcnv_cmd, transmits this converter power command signal to converter ECU 73, and then proceeds to step S8. As a result, power corresponding to target converter power Pcnv_cmd is charged or discharged from second battery B2.

[0094] Next, in step S8, the management ECU 71 generates an inverter through power command signal corresponding to the target inverter through power Pmot_cmd, sends the inverter through power command signal to the motor ECU 72, and ends the process. Figure 4 As a result, electric power corresponding to the target inverter pass power Pmot_cmd flows between the first power circuit 2 and the drive motor M. In addition, as a result, electric power obtained by subtracting the target converter pass power Pcnv_cmd from the target inverter pass power Pmot_cmd is charged or discharged from the first battery B1.

[0095] Next, in step S4, the management ECU 71 determines whether the driver has pressed an energy priority button (not shown). In other words, it determines whether the driver has not instructed to allow execution of the output priority mode, described below. If the determination result in step S4 is yes, the management ECU 71 proceeds to step S5, where it executes a limit process to limit the required inverter power passing through Pmot_d calculated in step S1 to less than a specified value, and then proceeds to step S3. In the limit process in step S5, the management ECU 71 limits the required inverter power passing through Pmot_d by, for example, setting the high output threshold value Phigh to the required inverter power passing through Pmot_d.

[0096] If the result of the determination in step S4 is negative, the management ECU 71 proceeds to step S6. In step S6, the management ECU 71 performs the following operations as shown in FIG. Figure 5A and Figure 5BAs described above, in the output priority mode that allows a larger inverter through-power than in the normal mode, the target converter through-power Pcnv_cmd and the target inverter through-power Pmot_cmd are calculated, and the process proceeds to step S7.

[0097] Figure 5A and Figure 5B This is a flowchart showing the procedure for calculating the target converter-passed power Pcnv_cmd and the target inverter-passed power Pmot_cmd in the output priority mode.

[0098] First, in step S11 , the management ECU 71 obtains the first temperature margin T1_mar and the second temperature margin T2_mar from the first battery ECU 74 and the second battery ECU 75 , respectively, and then proceeds to step S12 .

[0099] Next, in step S12 , the management ECU 71 obtains the first battery cooling margin PC1_mar and the second battery cooling margin PC2_mar from the cooling circuit ECU 76 , and the process proceeds to step S13 .

[0100] Next, in step S13 , the management ECU 71 obtains the first output upper limit P1_max and the second output upper limit P2_max from the first battery ECU 74 and the second battery ECU 75 , respectively, and the process proceeds to step S14 .

[0101] Next, in step S14, the management ECU 71 searches for the battery cooling margin PC1_mar and the battery cooling margin PC2_mar based on the first temperature margin T1_mar, the second temperature margin T2_mar, and the first battery cooling margin PC1_mar and the second battery cooling margin PC2_mar. Figure 6 The operation table shown in FIG. 1 is used to obtain information related to the priority output battery and output upper limit correction information.

[0102] Figure 6 This is a diagram showing an example of an operation table for determining the output and cooling method of the battery based on the temperature margin and the cooling margin.

[0103] exist Figure 6In the table, "temperature margin" indicates that the first temperature margin T1_mar is greater than or equal to the first temperature margin threshold, or the second temperature margin T2_mar is greater than or equal to the second temperature margin threshold. "no temperature margin" indicates that the first temperature margin T1_mar is less than or equal to the first temperature margin threshold, or the second temperature margin T2_mar is less than or equal to the second temperature margin threshold. "cooling margin" indicates that the first cooling margin PC1_mar is greater than or equal to the first cooling margin threshold, or the second cooling margin PC2_mar is greater than or equal to the second cooling margin threshold. Furthermore, "no cooling margin" indicates that the first cooling margin PC1_mar is less than or equal to the first cooling margin threshold, or the second cooling margin PC2_mar is less than or equal to the second cooling margin threshold.

[0104] Hereinafter, a case where the first temperature margin T1_mar is greater than or equal to the first temperature margin threshold is referred to as a case where the first battery B1 has a temperature margin, and a case where the first temperature margin T1_mar is less than the first temperature margin threshold is referred to as a case where the first battery B1 has no temperature margin. A case where the second temperature margin T2_mar is greater than or equal to the second temperature margin threshold is referred to as a case where the second battery B2 has a temperature margin, and a case where the second temperature margin T2_mar is less than the second temperature margin threshold is referred to as a case where the second battery B2 has no temperature margin. A case where the first cooling margin PC1_mar is greater than or equal to the first cooling margin threshold is referred to as a case where the first battery B1 has a cooling margin, and a case where the first cooling margin PC1_mar is less than the first cooling margin threshold is referred to as a case where the first battery B1 has no cooling margin. Furthermore, a case where the second cooling margin PC2_mar is greater than or equal to the second cooling margin threshold is referred to as a case where the second battery B2 has a cooling margin, and a case where the second cooling margin PC2_mar is less than the second cooling margin threshold is referred to as a case where the second battery B2 has no cooling margin.

[0105] The priority output battery represents a battery that is prioritized for output up to its output limit. As described below, if the priority output battery is the first battery B1, the first battery B1 is prioritized for outputting power up to its first output limit P1_max. If the priority output battery is the second battery B2, the second battery B2 is prioritized for outputting power up to its second output limit P2_max. If there is no priority output battery, the ratio between the output power of the first battery B1 and the output power of the second battery B2 is controlled to achieve a predetermined target ratio, as described below.

[0106] according to Figure 6In the example operation table shown, if first battery B1 has a temperature margin and room for cooling, first battery B1 is determined as the priority output battery. If second battery B2 has a temperature margin and room for cooling, second battery B2 is basically determined as the priority output battery. Furthermore, if both first battery B1 and second battery B2 have a temperature margin and room for cooling, first battery B1, which has a large heat capacity and is less likely to heat up, is determined as the priority output battery.

[0107] In addition, Figure 6 In the operation table shown in FIG. 1 , “first output upper limit: DOWN” indicates that the first output upper limit P1_max of the first battery B1 is corrected downward, and “second output upper limit: DOWN” indicates that the second output upper limit P2_max of the second battery B2 is corrected downward. Figure 6 In the example of the operation table shown, the first output upper limit P1_max is corrected downward when the first battery B1 has neither temperature margin nor cooling margin, and the second output upper limit P2_max is corrected downward when the second battery B2 has neither temperature margin nor cooling margin.

[0108] Back to Figure 5A In step S15 , the management ECU 71 corrects the first output upper limit P1_max and the second output upper limit P2_max based on the output upper limit correction information acquired in step S14 , and then proceeds to step S16 .

[0109] Next, in step S16, the management ECU 71 determines whether the demanded inverter power Pmot_d obtained in step S1 is greater than the sum of the first output upper limit P1_max and the second output upper limit P2_max. If the management ECU 71 determines yes in step S16, the process proceeds to step S17, where it performs a restriction process to limit the demanded inverter power Pmot_d to less than a specified value, and then proceeds to step S18. In the restriction process in step S17, the management ECU 71 limits the demanded inverter power Pmot_d by, for example, setting the sum of the first output upper limit P1_max and the second output upper limit P2_max as the demanded inverter power Pmot_d. If the management ECU 71 determines no in step S16, the process proceeds to step S18 without performing the restriction process described above.

[0110] Next, in step S18 , the management ECU 71 sets the required inverter-passing power Pmot_d as the target inverter-passing power Pmot_cmd, and the process proceeds to step S19 .

[0111] Next, in step S19, the management ECU 71 determines whether the priority output battery acquired in step S14 is the first battery B 1. The management ECU 71 proceeds to step S20 if the determination result in step S19 is yes, and proceeds to step S23 if the determination result in step S19 is no.

[0112] Next, in step S20, the management ECU 71 determines whether the required inverter power Pmot_d is greater than the first output upper limit P1_max. If the determination result of step S20 is yes, the management ECU 71 proceeds to step S21, sets the value obtained by subtracting the first output upper limit P1_max from the required inverter power Pmot_d as the target converter power Pcnv_cmd, and then proceeds to step S22. Figure 4 If the result of the determination in step S20 is negative, the management ECU 71 proceeds to step S22, sets the value 0 as the target converter passing power Pcnv_cmd, and proceeds to step S30. Figure 4 As described above, when the first battery B1 is set as the priority output battery, the first battery B1 is made to output electric power with priority over the second battery B2 up to the first output upper limit P1_max.

[0113] Next, in step S23, the management ECU 71 determines whether the priority output battery acquired in step S14 is the second battery B2. If the determination result in step S23 is yes, the management ECU 71 proceeds to step S24, and if the determination result in step S23 is no, the management ECU 71 proceeds to step S27.

[0114] Next, in step S24, the management ECU 71 determines whether the required inverter power Pmot_d is greater than the second output upper limit P2_max. If the determination result of step S24 is yes, the management ECU 71 proceeds to step S25, sets the second output upper limit P2_max as the target converter power Pcnv_cmd, and proceeds to step S26. Figure 4 If the result of the determination in step S24 is negative, the management ECU 71 proceeds to step S26, sets the required inverter through power Pmot_d to the target converter through power Pcnv_cmd, and proceeds to step S27. Figure 4 As described above, when the second battery B2 is set as the priority output battery, the second battery B2 is allowed to output electric power with higher priority than the first battery B1 up to the second output upper limit P2_max.

[0115] Next, in step S27, the management ECU 71 calculates a target ratio r, which corresponds to a target ratio of the output power of the second battery B2 to the output power of the first battery B1, and then proceeds to step S28. The management ECU 71 calculates the target ratio r based on, for example, the first SOC, the second SOC, the first output upper limit P1_max, and the second output upper limit P2_max, so that the output power of each battery B1 and B2 does not exceed the respective output upper limits P1_max and P2_max.

[0116] Next, in step S28, the management ECU 71 calculates the target converter transmission power Pcnv_cmd based on the following equation so that the power is output from the first battery B1 and the second battery B2 at the target ratio r, and then transfers to step S28. Figure 4 As described above, when neither the first battery B1 nor the second battery B2 is a priority output battery, the ratio of the output power of the first battery B1 to the output power of the second battery B2 is controlled so as to achieve the target ratio r.

[0117] Pcnv_cmd = Pmot_d × (r / (1+r))

[0118] As described above, when the operation mode is the output priority mode, the management ECU 71 controls the output power of the first battery B1 and the second battery B2 based on the required inverter passing power Pmot_d, the first cooling margin PC1_mar, the second cooling margin PC2_mar, the first temperature margin T1_mar, and the second temperature margin T2_mar.

[0119] In addition, as reference Figure 6 As described above, when first battery B1 has both a temperature margin and a cooling margin, management ECU 71 sets first battery B1 as the priority output battery. This allows first battery B1 to output power up to its first output upper limit, prioritizing second battery B2 over second battery B2. Therefore, when first battery B1 has both a temperature margin and a cooling margin, management ECU 71 increases the output power of first battery B1 compared to when first battery B1 has no temperature margin or no cooling margin.

[0120] Furthermore, when the second battery B2 has both a temperature margin and a cooling margin, the management ECU 71 basically sets the second battery B2 as the priority output battery, thereby giving the second battery B2 priority over the first battery B1 in outputting power up to its second output upper limit. Therefore, when the second battery B2 has both a temperature margin and a cooling margin, the management ECU 71 basically increases the output power of the second battery B2 compared to when the second battery B2 has no temperature margin or no cooling margin.

[0121] Furthermore, when both the first battery B1 and the second battery B2 have temperature margins and cooling margins, the management ECU 71 sets the first battery B1 having a larger heat capacity as the priority output battery. This allows the first battery B1 to output power to a first output upper limit with priority over the second battery B2.

[0122] In addition, as reference Figure 6 As described above, the management ECU 71 corrects the first upper output limit P1_max downward when the first battery B1 has neither a temperature margin nor a cooling margin. Therefore, when the first battery B1 has neither a temperature margin nor a cooling margin, the management ECU 71 reduces the output power of the first battery B1 compared to when the first battery B1 has a temperature margin or a cooling margin.

[0123] Furthermore, the management ECU 71 corrects the second upper output limit P2_max downward when the second battery B2 has neither a temperature margin nor a cooling margin. Therefore, when the second battery B2 has neither a temperature margin nor a cooling margin, the management ECU 71 makes the output power of the second battery B2 lower than when the second battery B2 has a temperature margin or a cooling margin.

[0124] Back to Figure 3 , a procedure for controlling the first cooling output and the second cooling output by the cooling circuit ECU 76 will be described.

[0125] As reference Figure 4 As described above, when the operation mode in the power management process is the output priority mode (see Figure 4 Step S6), it is allowed to operate in normal mode (refer to Figure 4 In step S3), a larger amount of power passes through the inverter. Therefore, when the operating mode is output priority mode, the heat generated by first battery B1 and second battery B2 tends to be greater than when the operating mode is normal mode. Therefore, the cooling circuit ECU 76 changes the control algorithm for the first and second cooling outputs according to the operating mode during power management processing.

[0126] First, a case where the operation mode is the normal mode will be described.

[0127] When the operating mode is normal mode, the cooling circuit ECU76 calculates the first control input for the first cooling device 91 (for example, the duty ratio of the motor driving the cooling fan) based on a known first basic cooling algorithm using the first battery temperature sent from the first battery ECU74, the detection value of the first cooling water temperature sensor, and the detection value of the external air temperature sensor, so that the first battery temperature reaches a predetermined first target temperature, and inputs the first control input to the first cooling device 91, thereby controlling the first cooling output.

[0128] In addition, when the operating mode is normal mode, the cooling circuit ECU76 calculates the second control input for the second cooling device 92 (for example, the duty cycle of the motor driving the cooling fan) based on a known second basic cooling algorithm using the second battery temperature sent from the second battery ECU75 and the detection value of the external air temperature sensor, so that the second battery temperature reaches a predetermined second target temperature, and inputs the second control input to the second cooling device 92, thereby controlling the second cooling output.

[0129] Next, a case where the operation mode is the output priority mode will be described.

[0130] When the operation mode is the output priority mode, the cooling circuit ECU 76 controls the first cooling output based on the first basic cooling algorithm, the first temperature margin T1_mar, and the first cooling margin PC1_mar. More specifically, the cooling circuit ECU 76 first searches for the first cooling output based on the first temperature margin T1_mar and the first cooling margin PC1_mar. Figure 6 The operation map shown in FIG. 1 is used to obtain information related to the first cooling mode of the first battery B1. Figure 6 In the example of the operation diagram, when the first battery B1 has sufficient cooling capacity, the first cooling mode is set to "active cooling." On the other hand, when the first battery B1 has no sufficient cooling capacity, the first cooling mode is set to "cooling max."

[0131] Next, the cooling circuit ECU 76 calculates the Figure 6Based on the first cooling mode information obtained from the operating map, the cooling circuit ECU 76 corrects the first control input calculated based on the first basic cooling algorithm and inputs this corrected first control input to the first cooling device 91, thereby controlling the first cooling output. When the first cooling mode is "aggressive cooling," the cooling circuit ECU 76 adds a correction value calculated based on the first temperature margin T1_mar to the first control input calculated based on the first basic cooling algorithm, thereby correcting the first control input toward improved cooling performance. Therefore, when the operating mode is output priority mode and the first cooling mode is "aggressive cooling," the cooling circuit ECU 76 increases the first cooling output compared to when the operating mode is normal mode. Furthermore, when the first cooling mode is "cooling max," the cooling circuit ECU 76 sets the first control input to its maximum value, regardless of the calculation result of the first control input based on the first basic cooling algorithm. Therefore, when the operating mode is output priority mode and the first cooling mode is "cooling max," the cooling circuit ECU 76 increases the first cooling output to the first maximum cooling output.

[0132] Furthermore, when the operation mode is the output priority mode, the cooling circuit ECU 76 controls the second cooling output based on the second basic cooling algorithm, the second temperature margin T2_mar, and the second cooling margin PC2_mar. More specifically, first, the cooling circuit ECU 76 retrieves the second cooling output based on the second temperature margin T2_mar and the second cooling margin PC2_mar. Figure 6 The operation diagram shown in FIG. 1 is used to obtain information related to the second cooling mode of the second battery B2. Figure 6 In the example of the operation diagram, when the second battery B2 has sufficient cooling capacity, the second cooling mode is set to "active cooling." On the other hand, when the second battery B2 has no sufficient cooling capacity, the second cooling mode is set to "cooling max."

[0133] Next, the cooling circuit ECU 76 calculates the Figure 6The cooling circuit ECU 76 uses the second cooling mode information obtained from the operating map to correct the second control input calculated based on the second basic cooling algorithm and input this corrected second control input to the second cooling device 92, thereby controlling the second cooling output. When the second cooling mode is "aggressive cooling," the cooling circuit ECU 76 adds a correction value calculated based on the second temperature margin T2_mar to the second control input calculated based on the second basic cooling algorithm, thereby correcting the second control input toward improved cooling performance. Therefore, when the operating mode is output priority mode and the second cooling mode is "aggressive cooling," the cooling circuit ECU 76 increases the second cooling output compared to when the operating mode is normal mode. Furthermore, when the second cooling mode is "cooling max," the cooling circuit ECU 76 sets the second control input to its maximum value, regardless of the calculation result of the second control input based on the second basic cooling algorithm. Therefore, when the operating mode is output priority mode and the second cooling mode is "cooling max," the cooling circuit ECU 76 increases the second cooling output to the second maximum cooling output.

[0134] According to the power supply system 1 of this embodiment, the following effects are produced.

[0135] (1) In normal mode or output priority mode, which allows a higher output than normal mode, the management ECU 71 controls the output power of batteries B1 and B2. The cooling circuit ECU 76 controls the first and second cooling outputs of the cooling devices 91 and 92. The cooling circuit ECU 76 obtains cooling margins PC1_mar and PC2_mar, which increase or decrease based on the difference between the first and second maximum cooling outputs of the cooling devices 91 and 92 and the first and second cooling outputs. Furthermore, when the operating mode is output priority mode and there is a cooling margin for the first battery B1, the cooling circuit ECU 76 increases the first cooling output compared to when the operating mode is normal mode. When the operating mode is output priority mode and there is a cooling margin for the second battery B2, the cooling circuit ECU 76 increases the second cooling output compared to when the operating mode is normal mode. Here, when the operating mode is output priority mode, the output of each battery B1 and B2 increases, and therefore, the amount of heat generated also tends to increase. Therefore, in power supply system 1, when batteries B1 and B2 have sufficient cooling capacity, that is, when there is room for increased cooling output, the cooling output is increased in anticipation of increases in heat generation from batteries B1 and B2. This allows batteries B1 and B2 to be maintained at appropriate temperatures in output priority mode, enabling rapid output increases based on demand. This also reduces the risk of excessive temperature increases in batteries B1 and B2, which could limit their output.

[0136] (2) Management ECU 71 controls the output power of batteries B1 and B2 based on the cooling margins PC1_mar and PC2_mar and the temperature margins T1_mar and T2_mar. This allows the output power of batteries B1 and B2 to be controlled to an appropriate level, anticipating the potential for increase in cooling output of cooling devices 91 and 92.

[0137] (3) When the operating mode is output mode and each battery B1, B2 has margin for cooling, as described above, the cooling circuit ECU 76 increases the cooling output of each cooling device 91, 92 compared to the normal mode. Furthermore, when each battery B1, B2 has margin for temperature and margin for cooling, the management ECU 71 increases the output power of each battery B1, B2 compared to the case where each battery B1, B2 has no margin for temperature or no margin for cooling. This increases the output power of each battery B1, B2 while also suppressing excessive temperature increases in each battery B1, B2.

[0138] (4) When batteries B1 and B2 have no cooling margin, the cooling circuit ECU 76 increases the cooling output of each cooling device 91 and 92 to its maximum cooling output. When batteries B1 and B2 have neither a temperature margin nor a cooling margin, the management ECU 71 reduces the output power of each battery B1 and B2 compared to the case where batteries B1 and B2 have no temperature margin or no cooling margin. This accelerates the temperature drop of each battery B1 and B2, allowing the output power of each battery B1 and B2 to be increased again.

[0139] (5) The battery ECUs 74 and 75 calculate the temperature margins T1_mar and T2_mar, respectively, based on the temperature difference between the upper limit temperature of each battery B1 and B2 and the current temperature, and the heat capacity of each battery B1 and B2. This allows the management ECU 71 to prevent excessive temperature increases in each battery B1 and B2, taking into account the heat capacity of each battery B1 and B2, and to control the output power of each battery B1 and B2 to an appropriate level.

[0140] <Second embodiment>

[0141] The power supply system of this embodiment differs from the power supply system 1 of the first embodiment in the order of calculating the first temperature margin T1_mar and the second temperature margin T2_mar and in the configuration of the operation table.

[0142] In the power supply system 1 of the first embodiment, the first battery ECU 74 calculates the first temperature margin by subtracting the first battery temperature from the first battery upper limit temperature, and the second battery ECU 75 calculates the second temperature margin by subtracting the second battery temperature from the second battery upper limit temperature.

[0143] In contrast, in the power supply system of this embodiment, the first battery ECU calculates a first temperature margin by multiplying a coefficient that increases or decreases based on the first heat capacity of the first battery B1 by a first temperature difference obtained by subtracting the first battery temperature from the first battery upper limit temperature. Furthermore, the second battery ECU calculates a second temperature margin by multiplying a coefficient that increases or decreases based on the second heat capacity of the second battery B2 by a second temperature difference obtained by subtracting the second battery temperature from the second battery upper limit temperature. In other words, the temperature margins of each of batteries B1 and B2 in the power supply system of this embodiment are corrected to values that increase with increasing heat capacity.

[0144] Figure 7 This is a diagram showing an example of an operation table referred to by the power supply system of this embodiment. Figure 7 The operation table shown is the same as Figure 6 The difference between the operation tables shown is the method of determining the priority output battery when both the first battery B1 and the second battery B2 have both a temperature margin and a cooling margin.

[0145] If both the first battery B1 and the second battery B2 have both a temperature margin and a cooling margin, the management ECU determines the battery with the greater temperature margin, either the first or the second, calculated based on thermal capacity as described above, as the priority output battery. More specifically, if the first temperature margin is greater than the second temperature margin, the management ECU determines the first battery B1 as the priority output battery, and if the second temperature margin is greater than the first temperature margin, the management ECU determines the second battery B2 as the priority output battery.

[0146] According to the power supply system of this embodiment, the following effects are produced.

[0147] (6) When both the first battery B1 and the second battery B2 have both a temperature margin and a cooling margin, the management ECU prioritizes the output of power to the battery having the greater temperature margin, T1_mar or T2_mar, calculated by taking the heat capacity into consideration as described above. This prevents excessive temperature increases in the batteries B1 and B2 and allows the output power of the batteries B1 and B2 to be controlled to an appropriate level.

[0148] (7) When both the first battery B1 and the second battery B2 have both sufficient temperature and cooling margins, the management ECU prioritizes the output of the first battery B1, which has a larger heat capacity, over the second battery B2, which has a smaller heat capacity. This prevents excessive temperature increases in each battery B1 and B2, while maintaining the appropriate output power levels for each battery B1 and B2.

[0149] While one embodiment of the present invention has been described above, the present invention is not limited thereto and the structure of the finer parts may be appropriately modified within the scope of the gist of the present invention.

[0150] Reference numerals

[0151] 1: Power system

[0152] 2: First power circuit

[0153] 3: Second power circuit

[0154] 4: Load circuit

[0155] 5: Voltage Converter

[0156] 7: Electronic control unit group

[0157] 9: Cooling circuit

[0158] 21n, 21p: First power line

[0159] 22n, 32n: Negative contactor

[0160] 22p, 32p: Positive contactor

[0161] 31n, 31p: Second power line

[0162] 33: Current sensor

[0163] 41n, 41p: Load power lines

[0164] 42: Vehicle auxiliary equipment

[0165] 43: Power Converter

[0166] 53, 54: Connecting nodes

[0167] 53H: First high arm component

[0168] 53L: First lower arm element

[0169] 54H: Second high arm element

[0170] 54L: Second lower arm element

[0171] 55: Negative bus

[0172] 56n, 56p: low-voltage side terminals

[0173] 57n, 57p: high-voltage side terminals

[0174] 71: Management ECU (power control unit, first cooling output control device)

[0175] 72: Motor ECU (Electric Power Control Unit)

[0176] 73: Converter ECU (Power Control Unit)

[0177] 74: First battery ECU

[0178] 75: Second battery ECU

[0179] 76: Cooling circuit ECU (first cooling output control device, second cooling output control device)

[0180] 81: First battery sensor unit

[0181] 82: Second battery sensor unit

[0182] 91: First cooling device

[0183] 92: Second cooling device

[0184] 93: The third cooling device

[0185] 94: Heating device

[0186] 911: First cooling water circulation path

[0187] 912: First heat exchanger

[0188] 913: First cooling water pump

[0189] 931: Third cooling water circulation path

[0190] 932: Third heat exchanger

[0191] 933: The third cooling water pump

[0192] 941: Bypass path

[0193] 942: Heater

[0194] 943: Heating pump

[0195] 944, 945: Three-way valve

[0196] B1: First battery (first power storage device)

[0197] B2: Second battery (second power storage device)

[0198] L1: first reactor

[0199] L2: Second reactor

[0200] M: drive motor

[0201] P: Pedal

[0202] P1_max: first output upper limit

[0203] P2_max: Second output upper limit

[0204] PC1_mar: First battery cooling margin

[0205] PC2_mar: Second battery cooling margin

[0206] Pcnv_cmd: Target converter passes power

[0207] Phigh: high output threshold

[0208] Pmot_cmd: The target inverter passes the power

[0209] Pmot_d: Demand inverter through power

[0210] r: target ratio

[0211] S1~S8, S11~S28: Steps

[0212] T1_mar: first temperature margin

[0213] T2_mar: Second temperature margin

[0214] V:Vehicle (moving object)

[0215] W: driving wheel

Claims

1. A power supply system comprising: a first power storage device; a second power storage device; a load circuit including a rotating motor; a power circuit connecting the first power storage device and the second power storage device to the load circuit; a power control unit that controls a first output power of the first power storage device and a second output power of the second power storage device in a normal mode or an output priority mode that allows a larger output from the power circuit to the load circuit than in the normal mode; a first cooling device for cooling the first power storage device; a second cooling device for cooling the second power storage device; as well as a cooling output control unit, configured to control a first cooling output of the first cooling device and a second cooling output of the second cooling device, The power supply system is characterized by comprising: a cooling margin acquisition unit configured to acquire a first cooling margin that increases or decreases according to a difference between a first maximum cooling output of the first cooling device and the first cooling output, and a second cooling margin that increases or decreases according to a difference between a second maximum cooling output of the second cooling device and the second cooling output; a temperature acquiring unit that acquires a first temperature of the first power storage device and a second temperature of the second power storage device; and a temperature margin acquisition unit that acquires a first temperature margin that increases or decreases according to a difference between a first upper limit temperature of the first power storage device and the first temperature, and a second temperature margin that increases or decreases according to a difference between a second upper limit temperature of the second power storage device and the second temperature; When the operation mode of the power control unit is the output priority mode and the first cooling margin is greater than a first cooling margin threshold, the cooling output control unit increases the first cooling output compared to when the operation mode is the normal mode. When the operation mode is the output priority mode and the second cooling margin is equal to or greater than a second cooling margin threshold, the cooling output control unit increases the second cooling output compared to when the operation mode is the normal mode. The power control unit controls the first output power and the second output power based on the first and second cooling margins and the first and second temperature margins.

2. The power supply system according to claim 1, wherein: When the first cooling margin is greater than or equal to the first cooling margin threshold and the first temperature margin is greater than or equal to the first temperature margin threshold, the power control unit increases the first output power compared to a case where the first cooling margin or the first temperature margin is less than or equal to the first cooling margin threshold or the first temperature margin threshold. When the second cooling margin is greater than the second cooling margin threshold and the second temperature margin is greater than the second temperature margin threshold, the power control unit makes the second output power greater than when the second cooling margin or the second temperature margin is less than the second cooling margin threshold or the second temperature margin threshold.

3. The power supply system according to claim 2, wherein: When the first cooling margin is less than the first cooling margin threshold, the cooling output control unit increases the first cooling output to the first maximum cooling output. When the second cooling margin is less than the second cooling margin threshold, the cooling output control unit increases the second cooling output to the second maximum cooling output. When the first cooling margin is less than the first cooling margin threshold and the first temperature margin is less than the first temperature margin threshold, the power control unit makes the first output power smaller than when the first cooling margin or the first temperature margin is equal to or greater than the first cooling margin threshold. When the second cooling margin is less than the second cooling margin threshold and the second temperature margin is less than the second temperature margin threshold, the power control unit makes the second output power smaller than when the second cooling margin or the second temperature margin is the second cooling margin threshold or above the second temperature margin threshold.

4. The power supply system according to claim 2 or 3, characterized in that: The temperature margin acquisition unit calculates the first temperature margin based on a first temperature difference between the first upper limit temperature and the first temperature and a first heat capacity of the first power storage device, and calculates the second temperature margin based on a second temperature difference between the second upper limit temperature and the second temperature and a second heat capacity of the second power storage device.

5. The power supply system according to claim 4, wherein: When the first cooling output and the second cooling output are respectively greater than the first cooling margin threshold and the second cooling margin threshold, and the first temperature margin and the second temperature margin are respectively greater than the first temperature margin threshold and the second temperature margin threshold, the power control unit gives priority to outputting the power storage device having the larger temperature margin of the first temperature margin or the second temperature margin.

6. The power supply system according to claim 2 or 3, characterized in that: The heat capacity of the first power storage device is greater than the heat capacity of the second power storage device, When the first cooling margin and the second cooling margin are respectively greater than the first cooling margin threshold and the second cooling margin threshold, and the first temperature margin and the second temperature margin are respectively greater than the first temperature margin threshold and the second temperature margin threshold, the power control unit causes the first power storage device to output with higher priority than the second power storage device.

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