Power supply system

Abstract

A power supply system is provided which is capable of outputting electric power from two power storage devices with less circuit loss. The power supply system is provided with: a power circuit which connects a first and a second battery with a load circuit; a power control means which controls the output electric power of the first and second batteries by operating the first and second power circuits; and a permissible output upper limit acquisition means which acquires a first permissible output upper limit P1_lim for the output electric power of the first battery and a second permissible output upper limit P2_lim for the output electric power of the second battery; and the power control means switches a battery output control mode to a first priority output mode or a second priority output mode based on a first battery temperature T1 and a second battery temperature T2, the first priority output mode being to increase the output electric power of the first battery to the first permissible output upper limit P1_lim in preference to the second battery, and the second priority output mode being to increase the output electric power of the second battery to the second permissible output upper limit P2_lim in preference to the first battery.

Description

Technical Field

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

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

[0003] For example, Patent Document 1 discloses a power 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. According to this power system with two batteries having different characteristics, it is possible, for example, to drive using only the power output from the capacity-type battery, or to drive using power obtained by combining the power output from the capacity-type battery and the power output from the output-type battery.

[0004] [Existing Technical Documents]

[0005] [Patent Literature]

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

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

[0008] However, if power is supplied from the battery to the drive motor via the electrical circuit, various circuit losses will occur. Furthermore, among the circuit losses generated in the entire power system, the losses caused by the internal resistance of the battery are the greatest. However, conventional power systems have not adequately considered the circuit losses that occur when power is output from each battery.

[0009] The purpose of this invention is to provide a power supply system that can output power from two energy storage devices with less circuit loss.

[0010] [Technical means to solve the problem]

[0011] (1) The power supply system of the present invention (e.g., power supply system 1 below) includes: a first energy storage device (e.g., first battery B1 below); a second energy storage device (e.g., second battery B2 below); a load circuit (e.g., load circuit 4 below), which includes a rotary motor (e.g., drive motor M below); a power circuit (e.g., first power circuit 2 and second power circuit 3 below), which connects the first and second energy storage devices to the load circuit; and a power control means (e.g., management electronic control unit below). Unit (ECU) 71, motor ECU 72, and converter ECU 73) control the output power of the first and second energy storage devices by operating the power circuit; the power system is characterized by having: temperature acquisition means (e.g., the first battery ECU 74, the second battery ECU 75, the first battery sensor unit 81, and the second battery sensor unit 82 described below), which acquires the temperature of the first energy storage device, i.e., a first temperature (e.g., the first battery temperature T1 described below), and the temperature of the second energy storage device, i.e., a second temperature (e.g., the second battery temperature T2 described below); and a permitted output limit acquisition means (e.g., the management ECU 71, the first battery ECU 74, the second battery ECU 75, and the first battery sensor unit 82 described below). The unit 81 and the second battery sensor unit 82 acquire a first permissible output limit (e.g., the first permissible output limit P1_lim below) for the output power of the first energy storage device and a second permissible output limit (e.g., the second permissible output limit P2_lim below) for the output power of the second energy storage device; and the power control means, based on the first and second temperatures, switches the control mode to a first priority output mode or a second priority output mode, wherein the first priority output mode increases the output power of the first energy storage device to the first permissible output limit before the second energy storage device, and the second priority output mode increases the output power of the second energy storage device to the second permissible output limit before the first energy storage device.

[0012] (2) In this case, preferably, the power system further includes: a cooling circuit (e.g., the cooling circuit 9 and its first cooling device 91 and second cooling device 92 described below) that cools the first energy storage device and the second energy storage device; and a cooling output control means (e.g., the cooling circuit ECU 76 described below) that controls the first cooling output of the cooling circuit for the first energy storage device and the second cooling output of the energy storage device for the second energy storage device; and the cooling output control means, when the first temperature is less than (below) a first temperature standard value (e.g., the first temperature standard value T1_bs described below), reduces the first cooling output compared to when the first temperature is above the first temperature standard value, and when the second temperature is less than a second temperature standard value (e.g., the second temperature standard value T2_bs described below), reduces the second cooling output compared to when the second temperature is above the second temperature standard value.

[0013] (3) In this case, it is preferable that the power control means sets the control mode to the first priority output mode when the first temperature is above the first temperature standard value and the second temperature is below the second temperature standard value, and sets the control mode to the second priority output mode when the first temperature is below the first temperature standard value and the second temperature is above the second temperature standard value.

[0014] (4) In this case, preferably, the power system further includes a loss acquisition means (e.g., the management ECU 71 described below), which acquires a first loss (e.g., the first loss Ploss1 described below) and a second loss (e.g., the second loss Ploss2 described below), wherein the first loss is the loss generated by the first energy storage device and the power circuit when the control mode is set to the first priority output mode, and the second loss is the loss generated by the second energy storage device and the power circuit when the control mode is set to the second priority output mode; and wherein the power control means sets the control mode to the second priority output mode when the first temperature is above the first temperature standard value and the second temperature is above the second temperature standard value, and the first loss is greater than the second loss, and sets the control mode to the first priority output mode when the second loss is greater than the first loss.

[0015] (5) In this case, preferably, the power supply system further comprises: a first power circuit (e.g., the first power circuit 2 below) having the first energy storage device; a second power circuit (e.g., the second power circuit 3 below) having the second energy storage device; a voltage converter (e.g., the voltage converter 5 below) for converting voltage between the first power circuit and the second power circuit; and a power converter (e.g., the power converter 43 below) for connecting the first power circuit to the rotary motor; and the power control means, when the first temperature is above the first temperature standard value and the second temperature is above the second temperature standard value, sets the control mode to the first priority output mode.

[0016] (6) In this case, it is preferable that the heat capacity of the second energy storage device is less than that of the first energy storage device, and that the power control means sets the control mode to the second priority output mode when the first temperature is less than the first temperature standard value and the second temperature is less than the second temperature standard value.

[0017] [The effects of the invention]

[0018] (1) Among the circuit losses generated in a power system that connects the first and second energy storage devices to the load circuit using an electrical circuit, the circuit losses generated by the first or second energy storage device are particularly large. Furthermore, the circuit losses generated by the first and second energy storage devices vary depending on their respective temperatures. In this invention, the power control means, based on the first and second temperatures, switches the control mode to a first priority output mode or a second priority output mode. The first priority output mode increases the output power of the first energy storage device to a first permissible output limit before the second energy storage device, and the second priority output mode increases the output power of the second energy storage device to a second permissible output limit before the first energy storage device. Therefore, according to this invention, it is possible to switch the energy storage device used in a preferred manner to reduce the circuit losses generated in the entire power system. Furthermore, by reducing circuit losses, it is also possible to continuously drive the rotary motor for a longer period of time.

[0019] (2) In this invention, the cooling output control means, when the first temperature is less than the first temperature standard value, reduces the first cooling output of the cooling circuit compared to when the first temperature is above the first temperature standard value; and when the second temperature is less than the second temperature standard value, reduces the second cooling output of the cooling circuit compared to when the second temperature is above the second temperature standard value. Thus, while rapidly increasing both the first and second temperatures, it is possible to suppress power consumption in the cooling circuit, thereby enabling the continuous operation of the rotary motor for a longer period.

[0020] (3) The power control method sets the control mode to the first priority output mode when the first temperature is above the first temperature standard value and the second temperature is below the second temperature standard value, so that the first energy storage device with the higher temperature discharges first. This reduces circuit losses compared to the case where the second energy storage device with the lower temperature discharges first. Furthermore, the power control method sets the control mode to the second priority output mode when the first temperature is below the first temperature standard value and the second temperature is above the second temperature standard value, so that the second energy storage device with the higher temperature discharges first. This also reduces circuit losses compared to the case where the first energy storage device with the lower temperature discharges first.

[0021] (4) In this invention, the loss acquisition means acquires a first loss when the control mode is set to a first priority output mode, and a second loss when the control mode is set to a second priority output mode. Furthermore, the power control means, when the first loss is greater than the second loss if the first temperature is above a first temperature standard value and the second temperature is above a second temperature standard value, sets the control mode to a second priority output mode with lower loss; and when the second loss is greater than the first loss, sets the control mode to a first priority output mode with lower loss. This further reduces circuit losses in the power supply system.

[0022] (5) In this invention, the first energy storage device is connected to the rotating electric machine via a power converter, and the second energy storage device is connected to the rotating electric machine via both a power converter and a voltage converter. Therefore, assuming that the circuit losses in the first energy storage device and the second energy storage device are equal, in the second priority output mode, more power passes through the voltage converter than in the first priority output mode, resulting in greater losses in the second priority output mode. Therefore, the power control means, when the first temperature is above the first temperature standard value and the second temperature is above the second temperature standard value, sets the control mode to the lower-loss first priority output mode. This further reduces circuit losses in the power supply system.

[0023] (6) In this invention, the power control means, when the first temperature is less than the first temperature standard value and the second temperature is less than the second temperature standard value, sets the control mode to the second priority output mode, so that the second energy storage device with a smaller heat capacity is discharged first. This enables the second energy storage device to heat up quickly, thereby further reducing circuit losses in the power supply system. Attached Figure Description

[0024] Figure 1 A diagram illustrating the structure of a vehicle equipped with a power supply system according to the first embodiment of the present invention.

[0025] Figure 2This is a diagram illustrating an example of the circuit structure of a voltage converter.

[0026] Figure 3 A diagram illustrating an example of the circuit structure of a cooling circuit.

[0027] Figure 4 A flowchart illustrating the specific procedures for power management processing.

[0028] Figure 5A A flowchart (one) illustrating the specific procedure for processing the target through power calculation.

[0029] Figure 5B A flowchart (Part Two) illustrating the specific procedure for processing the target through power calculation.

[0030] Figure 6 A diagram illustrating an example of a control mode determination table.

[0031] Figure 7 This diagram illustrates an example of a control mode determination table for a power supply system according to a second embodiment of the present invention. Detailed Implementation

[0032] [First Implementation]

[0033] The first embodiment of the present invention will now be described with reference to the accompanying drawings.

[0034] Figure 1 This diagram illustrates the structure of a four-wheeled electric vehicle V (hereinafter referred to as "vehicle") equipped with the power system 1 of this embodiment. Furthermore, this embodiment describes the case where the power system 1 is mounted in the four-wheeled vehicle V, but the present invention is not limited thereto. The power system of the present invention is not limited to the four-wheeled vehicle V, but is also applicable to mobile bodies that move using propulsion generated by a rotary motor, such as ride-on vehicles, ships, robots, and unmanned aerial vehicles.

[0035] The vehicle V includes: a drive wheel W; a drive motor M connected to the drive wheel W as a rotary motor; and a power system 1 that supplies and receives power between the drive motor M and the first battery B1 and the second battery B2 described below. In this embodiment, the vehicle V is primarily described as a vehicle that accelerates and decelerates using the power generated by the drive motor M, but the invention is not limited to this. The vehicle V can also be a so-called hybrid vehicle equipped with a drive motor M and an engine as power sources.

[0036] A drive motor M is connected to the drive wheel W via a power transmission mechanism (not shown). The torque generated by the drive motor M, supplied with three-phase AC power from the power system 1, is transmitted to the drive wheel W via the power transmission mechanism (not shown), causing the drive wheel W to rotate and thus propelling the vehicle V. Furthermore, the drive motor M functions as a generator when the vehicle V decelerates, generating regenerative power and imparting a regenerative braking torque corresponding to the magnitude of this regenerative power to the drive wheel W. The regenerative power generated by the drive motor M appropriately charges the batteries B1 and B2 of the power system 1.

[0037] 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 power circuit 2 and the second power circuit 3; a load circuit 4 having various electrical loads including a drive motor M; a cooling circuit 9 for cooling either the first battery B1 or the second battery B2; and an electronic control unit group 7 that controls the flow of power in the power circuits 2, 3, and 4, the charging and discharging of batteries B1 and B2, and the cooling output of the cooling circuit 9 by operating the power circuits 2, 3, and 4, the cooling circuit 9, and the voltage converter 5. The electronic control unit group 7 includes a management ECU 71 (which functions as a computer), a motor ECU 72, a converter ECU 73, a first battery ECU 74, a second battery ECU 75, and a cooling circuit ECU 76.

[0038] The first battery B1 is a secondary battery capable of simultaneously converting chemical energy into electrical energy through discharge and electrical energy into chemical energy through charging. Hereinafter, a case will be described using a so-called lithium-ion battery that utilizes the movement of lithium ions between electrodes for charging and discharging as this first battery B1, but the present invention is not limited thereto.

[0039] The first battery B1 is provided with a first battery sensor unit 81 for inferring the internal state of the first battery B1. The first battery sensor unit 81 consists of multiple sensors that detect physical quantities such as the charge rate (expressed as a percentage of battery capacity) or temperature required to obtain the remaining amount of the first battery B1 in the first battery ECU 74, and send signals corresponding to the detected values ​​to the first battery ECU 74. More specifically, the first battery sensor unit 81 consists of a voltage sensor for detecting the terminal voltage of the first battery B1, a current sensor for detecting the current flowing in the first battery B1, and a temperature sensor for detecting the temperature of the first battery B1.

[0040] The second battery B2 is a secondary battery capable of simultaneously converting chemical energy into electrical energy through discharge and electrical energy into chemical energy through charging. Hereinafter, the case where a so-called lithium-ion battery, which utilizes the movement of lithium ions between electrodes for charging and discharging, is used as this second battery B2 will be described, but the present invention is not limited thereto. For example, a capacitor may also be used as the second battery B2.

[0041] The second battery B2 is equipped with a second battery sensor unit 82 for inferring the internal state of the second battery B2. The second battery sensor unit 82 consists of multiple sensors that detect physical quantities necessary for obtaining the charging rate or temperature of the second battery B2 in the second battery ECU 75, and send signals corresponding to the detected values ​​to the second battery ECU 75. More specifically, the second battery sensor unit 82 consists of a voltage sensor for detecting the terminal voltage of the second battery B2, a current sensor for detecting the current flowing in the second battery B2, and a temperature sensor for detecting the temperature of the second battery B2.

[0042] Here, the characteristics of the first battery B1 are compared with those of the second battery B2.

[0043] Compared to the second battery B2, the first battery B1 has a lower output weight density and a higher energy weight density. Furthermore, the first battery B1 has a larger discharge capacity than the second battery B2. In other words, the first battery B1 is superior to the second battery B2 in terms of energy weight density. 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, with its superior energy weight density, is a capacity-type energy storage device primarily designed for high capacity, while the second battery B2, with its superior output weight density, is an output-type energy storage device primarily designed for high output. Therefore, in the power system 1, the first battery B1 is used as the main power source, and the second battery B2 is used as an auxiliary power source to assist the first battery B1. Additionally, the second battery B2 has a smaller heat capacity than the first battery B1. Therefore, the temperature of the second battery B2 rises faster than that of the first battery B1.

[0044] The first power circuit 2 includes: a first battery B1; first power lines 21p and 21n, which connect the positive and negative terminals of the first battery B1 to the positive and negative terminals of the high-voltage side of the voltage converter 5; and a positive contactor 22p and a negative contactor 22n, which are provided on the first power lines 21p and 21n.

[0045] Contactors 22p and 22n are normally open. They open when there is no external command signal input to disconnect the two electrodes of the first battery B1 from the first power lines 21p and 21n. They close when there is a command signal input to connect the first battery B1 to the first power lines 21p and 21n. These contactors 22p and 22n open and close according to the command signal sent from the first battery ECU 74. Furthermore, the positive contactor 22p is a pre-charge contactor with a pre-charge resistor, which is used to mitigate the inrush current flowing to the multiple smoothing capacitors disposed in the first power circuit 2 or the load circuit 4, etc.

[0046] The second power circuit 3 includes: a second battery B2; second power lines 31p and 31n, which connect the positive and negative terminals of the second battery B2 to the positive and negative terminals of the low-voltage side of the voltage converter 5; a positive contactor 32p and a negative contactor 32n, which are provided on the second power lines 31p and 31n; and a current sensor 33, which is provided on the second power line 31p.

[0047] Contactors 32p and 32n are normally open. They open when there is no external command signal input to disconnect the two electrodes of the second battery B2 from the second power lines 31p and 31n. They close when there is a command signal input to connect the second battery B2 to the second power lines 31p and 31n. These contactors 32p and 32n open and close according to the command signal sent from the second battery ECU 75. Furthermore, the positive contactor 32p is a pre-charge contactor with a pre-charge resistor, which is used to mitigate the inrush current flowing to the multiple smoothing capacitors installed in the first power circuit 2 or the load circuit 4, etc.

[0048] The current sensor 33 sends a detection signal corresponding to the current flowing through it to the converter ECU 73. This current is the current flowing in the second power line 31p, i.e., the current flowing in the voltage converter 5. Furthermore, in this embodiment, the direction of the current flowing through it is set as positive from the second power circuit 3 side to the first power circuit 2 side, and negative from the first power circuit 2 side to the second power circuit 3 side. That is, the current flowing through the voltage converter 5 is positive when the second battery B2 is discharging and negative when the second battery B2 is charging.

[0049] The load circuit 4 includes: a vehicle auxiliary machine 42; a power converter 43 connected to a drive motor M; and load power lines 41p and 41n that connect the vehicle auxiliary machine 42 and the power converter 43 to the first power circuit 2.

[0050] The vehicle auxiliary unit 42 consists of multiple electrical loads, including a battery heater, an air compressor, a DC-DC converter, and an on-board charger. The vehicle auxiliary unit 42 is connected to the first power lines 21p and 21n of the first power circuit 2 via load power lines 41p and 41n, and operates by consuming power from the first power lines 21p and 21n. Information related to the operating status of the various electrical loads constituting the vehicle auxiliary unit 42 is sent, for example, to the management ECU 71.

[0051] The power converter 43 is connected to the first power lines 21p and 21n in parallel with the vehicle auxiliary machine 42, utilizing load power lines 41p and 41n. The power converter 43 converts power between the first power lines 21p and 21n and the drive motor M. The power converter 43 is, for example, a pulse-width modulation (PWM) inverter equipped with a bridge circuit bridging multiple switching elements (e.g., insulated-gate bipolar transistors, IGBTs) and utilizing pulse-width modulation, and has the function of converting DC power to AC power. The power converter 43 has its DC input / output side connected to the first power lines 21p and 21n, and its AC input / output side connected to the coils of the U-phase, V-phase, and W-phase of the drive motor M. The power converter 43 drives the switching elements of each phase to turn on / off according to the gate drive signal generated from the gate drive circuit (not shown) of the motor ECU 72 at a predetermined time. As a result, it converts the DC power of the first power lines 21p and 21n into three-phase AC power and supplies it to the drive motor M, or converts the three-phase AC power supplied from the drive motor M into DC power and supplies it to the first power lines 21p and 21n.

[0052] Voltage converter 5 connects the first power circuit 2 and the second power circuit 3, and transforms the voltage between the two circuits 2 and 3. This voltage converter 5 uses a known boost circuit.

[0053] Figure 2This diagram illustrates an example of the circuit structure of voltage converter 5. Voltage converter 5 connects the first power lines 21p and 21n connected to the first battery B1 and the second power lines 31p and 31n connected to the second battery B2, and transforms the voltage between the first power lines 21p and 21n and the second power lines 31p and 31n. Voltage converter 5 is a full-bridge DC-DC converter, constructed by combining a first reactor L1, a second reactor L2, a first high-arm element 53H, a first low-arm element 53L, a second high-arm element 54H, a second low-arm element 54L, a negative bus 55, low-voltage side terminals 56p and 56n, high-voltage side terminals 57p and 57n, and a smoothing capacitor (not shown).

[0054] Low-voltage side terminals 56p and 56n are connected to the second power line 31p and 31n, and high-voltage side terminals 57p and 57n are connected to the first power line 21p and 21n. Negative busbar 55 is the wiring that connects the low-voltage side terminal 56n to the high-voltage side terminal 57n.

[0055] One end of the first reactor L1 is connected to the low-voltage side terminal 56p, and the other end is connected to the connection node 53 between the first high-arm element 53H and the first low-arm element 53L. The first high-arm element 53H and the first low-arm element 53L each possess a known power switching element such as an IGBT or a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET), and a return-current diode connected to this power switching element. The high-arm element 53H and the low-arm element 53L are connected in series between the high-voltage side terminal 57p and the negative bus 55 in the aforementioned order.

[0056] The collector of the power switching element of the first high-arm element 53H is connected to the high-voltage side terminal 57p, and its emitter is connected to the collector of the first low-arm element 53L. The emitter of the power switching element of the first low-arm element 53L is connected to the negative bus 55. The return diode provided on the first high-arm element 53H is oriented from the first reactor L1 toward the high-voltage side terminal 57p. Similarly, the return diode provided on the first low-arm element 53L is oriented from the negative bus 55 toward the first reactor L1.

[0057] One end of the second reactor L2 is connected to the low-voltage side terminal 56p, and the other end is connected to the connection node 54 between the second high-arm element 54H and the second low-arm element 54L. The second high-arm element 54H and the second low-arm element 54L each have a known power switching element such as an IGBT or MOSFET, and a return-current diode connected to the power switching element. The aforementioned high-arm element 54H and low-arm element 54L are connected in series between the high-voltage side terminal 57p and the negative bus 55 in the order described.

[0058] The collector of the power switching element of the second high-arm element 54H is connected to the high-voltage side terminal 57p, and its emitter is connected to the collector of the second low-arm element 54L. The emitter of the power switching element of the second low-arm element 54L is connected to the negative bus 55. The return diode provided on the second high-arm element 54H is oriented from the second reactor L2 toward the high-voltage side terminal 57p. Similarly, the return diode provided on the second low-arm element 54L is oriented from the negative bus 55 toward the second reactor L2.

[0059] The voltage converter 5 alternately turns on / off the first high arm element 53H and the second low arm element 54L, and the first low arm element 53L and the second high arm element 54H, according to the gate drive signal generated from the gate drive circuit (not shown) of the converter ECU73 at a predetermined time, thereby changing the voltage between the first power lines 21p, 21n and the second power lines 31p, 31n.

[0060] The static voltage of the second battery B2 is maintained at a level lower than that of the first battery B1. Therefore, the voltage of the first power lines 21p and 21n is generally higher than that of the second power lines 31p and 31n. Thus, when driving the drive motor M using both the power output from the first battery B1 and the power output from the second battery B2, the converter ECU 73 operates the voltage converter 5 to perform a boost function. The boost function refers to boosting the power of the second power lines 31p and 31n connected to the low-voltage side terminals 56p and 56n and outputting it to the first power lines 21p and 21n connected to the high-voltage side terminals 57p and 57n, thereby allowing positive current to flow from the second power lines 31p and 31n side to the first power lines 21p and 21n side. In addition, when suppressing the discharge of the second battery B2 and using only the power output from the first battery B1 to drive the drive motor M, the converter ECU73 disconnects the voltage converter 5 so that current does not flow from the first power lines 21p and 21n to the second power lines 31p and 31n.

[0061] Additionally, during deceleration, the regenerative power output from the drive motor M to the first power lines 21p and 21n is used to charge either the first battery B1 or the second battery B2. In this case, the converter ECU 73 operates the voltage converter 5 to perform a step-down function. The step-down function refers to the function of stepping down the power of the first power lines 21p and 21n connected to the high-voltage side terminals 57p and 57n, and outputting it to the second power lines 31p and 31n connected to the low-voltage side terminals 56p and 56n. This causes a negative current to flow from the first power lines 21p and 21n side to the second power lines 31p and 31n side.

[0062] Return to Figure 1 The first battery ECU 74 is a computer primarily responsible for monitoring the status of the first battery B1 and controlling the opening and closing of contactors 22p and 22n in the first power circuit 2. Based on a known algorithm using detection values ​​sent from the first battery sensor unit 81, the first battery ECU 74 calculates various parameters representing the internal state of the first battery B1. More specifically, it calculates the temperature of the first battery B1 (hereinafter also referred to as "first battery temperature"), the internal resistance of the first battery B1, the static voltage of the first battery B1, the closed-circuit voltage of the first battery B1, the first charging rate corresponding to the charging rate of the first battery B1, and the degree of degradation of the first battery B1. Information related to the parameters representing the internal state of the first battery B1 obtained by the first battery ECU 74 is, for example, sent to the management ECU 71.

[0063] The second battery ECU 75 is a computer primarily responsible for monitoring the status of the second battery B2 and controlling the opening and closing of contactors 32p and 32n in the second power circuit 3. Based on a known algorithm using detection values ​​sent from the second battery sensor unit 82, the second battery ECU 75 calculates various parameters representing the internal state of the second battery B2. More specifically, it calculates the temperature of the second battery B2 (hereinafter also referred to as "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 charging rate equivalent to the charging rate of the second battery B2, and the degree of degradation of the second battery B2. Information related to the parameters representing the internal state of the second battery B2 obtained by the second battery ECU 75 is, for example, sent to the management ECU 71.

[0064] The management ECU 71 is the computer that primarily manages the flow of power throughout the entire power system 1. The management ECU 71 performs operations as described below. Figure 4 The power management process described generates an inverter power command signal and a converter power command signal. The inverter power command signal is equivalent to an instruction for the power passing through the power converter 43, i.e., the power passing through the inverter. The converter power command signal is equivalent to an instruction for the power passing through the voltage converter 5, i.e., the power passing through the converter.

[0065] The motor ECU 72 is a computer that primarily operates the power converter 43 to control the flow of power between the first power circuit 2 and the drive motor M, i.e., the flow of power through the inverter. Furthermore, the inverter power flow is positive when power flows from the first power circuit 2 to the drive motor M, i.e., when the drive motor M is running under power. Conversely, the inverter power flow is negative when power flows from the drive motor M to the first power circuit 2, i.e., when the drive motor M is regenerating. The motor ECU 72 operates the power converter 43 according to the inverter power flow command signal sent from the management ECU 71, so that the inverter power flow corresponding to the command passes through the power converter 43; in other words, it generates torque in the drive motor M corresponding to the inverter power flow.

[0066] The converter ECU 73 is a computer that primarily operates the voltage converter 5 to control the flow of power between the first power circuit 2 and the second power circuit 3, i.e., the converter's power flow. The converter's power flow is positive when power flows from the second power circuit 3 to the first power circuit 2, i.e., when power is released from the second battery B2 and supplied to the first power circuit 2. Conversely, the converter's power flow is negative when power flows from the first power circuit 2 to the second power circuit 3, i.e., when power from the first power circuit 2 is used to charge the second battery B2. The converter ECU 73 operates the voltage converter 5 according to the converter power flow command signal sent from the management ECU 71, causing the converter to flow power according to the command. More specifically, the converter ECU 73 calculates a target current based on the converter power flow command signal, which is a target current for the current flowing through the voltage converter 5, and operates the voltage converter 5 according to a known feedback control algorithm to make the current flowing through the voltage converter (hereinafter also referred to as the "actual current flowing through") detected by the current sensor 33 reach the target current.

[0067] As described above, in power system 1, the voltage converter 5 and power converter 43 are operated using the management ECU 71, motor ECU 72, and converter ECU 73 to control the power flowing through the voltage converter 5 or power converter 43. This allows control of the output power of the first battery B1 (i.e., the first battery output power) and the output power of the second battery B2 (i.e., the second battery output power). Therefore, in this embodiment, the power control means for controlling the output power of the first battery and the output power of the second battery is composed of the management ECU 71, motor ECU 72, and converter ECU 73. More specifically, by using the above-mentioned power control means to control the power of the converter to P2 and the power of the inverter to P1+P2, the output power of the first battery and the output power of the second battery can be controlled as P1 and P2, respectively.

[0068] Figure 3 A diagram showing the circuit structure of cooling circuit 9.

[0069] The cooling circuit 9 includes: a first cooling device 91 for cooling the first battery B1; a second cooling device 92 for cooling the second battery B2; and a third cooling device 93 for cooling the voltage converter 5 and the power converter 43.

[0070] The first cooling device 91 includes: a first cooling water circulation path 911, which includes a cooling water flow channel formed on the battery casing accommodating the first battery B1; a first heat exchanger 912 and a first cooling water pump 913 disposed on the first cooling water circulation path 911; and a heating device 94 connected to the first cooling water circulation path 911.

[0071] The first cooling water pump 913 rotates according to a command input from the cooling circuit ECU 76, causing cooling water to circulate within the first cooling water circulation path 911. The first heat exchanger 912 facilitates heat exchange between the cooling water circulating within the first cooling water circulation path 911 and the outside air, thereby cooling the cooling water that has heated up due to heat exchange with the first battery B1. The first heat exchanger 912 includes a cooling fan that rotates according to a command input from the cooling circuit ECU 76.

[0072] The heating device 94 includes: a bypass flow path 941 that connects the inlet and outlet of the first heat exchanger 912 in the first cooling water circulation path 911 and bypasses the first heat exchanger 912; a heater 942 and a heating pump 943, which are provided on the bypass flow path 941; and three-way valves 944 and 945, which are provided at both ends of the bypass flow path 941 and the connection portion of the first cooling water circulation path 911.

[0073] The heating pump 943 rotates according to the command input from the cooling circuit ECU 76, causing the cooling water to circulate in the first cooling water circulation path 911 and the bypass flow path 941. The heater 942 consumes power supplied by a battery (not shown) to generate heat, thereby warming the cooling water flowing in the bypass flow path 941.

[0074] Three-way valves 944 and 945 open and close according to commands from the cooling circuit ECU 76, switching the flow path of cooling water between the first heat exchanger 912 side and the heater 942 side. Therefore, the first cooling device 91 has both cooling and heating functions. The cooling function utilizes the cooling water cooled by the first heat exchanger 912 to cool the first battery B1, and the heating function utilizes the cooling water heated by the heater 942 to heat the first battery B1.

[0075] The cooling circuit ECU 76 operates the first heat exchanger 912, the first cooling water pump 913, the heater 942, the heating pump 943, and the three-way valves 944 and 945 based on the first battery temperature sent from the first battery ECU 74, the detection value of the first cooling water temperature sensor (not shown) that detects the temperature of the cooling water flowing in the first cooling water circulation path 911, the detection value of the external 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. Here, the first cooling output refers to a parameter that increases or decreases depending on the cooling performance of the first cooling device 91 for the first battery B1, such as setting the speed of the cooling fan on the first heat exchanger 912. The specific procedure for controlling the first cooling output in the cooling circuit ECU 76 will be described below.

[0076] The second cooling device 92 includes, for example, a cooling fan that supplies external air into the battery casing housing the second battery B2. The second cooling device 92 rotates according to instructions from the cooling circuit ECU 76, supplying external air into the battery casing of the second battery B2, thereby cooling the second battery B2.

[0077] 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 external 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 refers to a parameter that increases or decreases depending on the cooling performance of the second cooling device 92 for the second battery B2, such as the rotational speed of the cooling fan of the second cooling device 92. Furthermore, the specific procedure for controlling the second cooling output in the cooling circuit ECU 76 will be described below.

[0078] The third cooling device 93 includes: a third cooling water circulation path 931, which includes a cooling water flow channel formed on a frame on which the voltage converter 5 and the power converter 43 are provided; and a third heat exchanger 932 and a third cooling water pump 933, which are provided on the third cooling water circulation path 931.

[0079] The third cooling water pump 933 rotates according to a command input from the cooling circuit ECU 76, causing cooling water to circulate within the third cooling water circulation path 931. The third heat exchanger 932 facilitates heat exchange between the cooling water circulating within the third cooling water circulation path 931 and the outside air, thereby cooling the cooling water that has heated up due to heat exchange with the voltage converter 5 and the power converter 43. The third heat exchanger 932 is equipped with a cooling fan that rotates according to a command input from the cooling circuit ECU 76.

[0080] The cooling circuit ECU 76 operates the third heat exchanger 932 and the third cooling water pump 933 based on the detection value of a cooling water temperature sensor (not shown) or instructions from the management ECU 71, thereby controlling the third cooling output, which corresponds to the cooling performance of the third cooling device 93 for the voltage converter 5 or the power converter 43.

[0081] As described above, in this embodiment, the first cooling device 91 for cooling the first battery B1 and the third cooling device 93 for cooling the voltage converter 5, etc., are water-cooled and cooled by heat exchange with cooling water. The second cooling device 92 for cooling the second battery B2, whose heat capacity is less than that of the first battery B1, is air-cooled and cooled by heat exchange with outside air. However, the present invention is not limited to this. The first cooling device 91 may also be air-cooled, the second cooling device 92 may also be water-cooled, and the third cooling device 93 may also be air-cooled. In addition, in this embodiment, the circulation channel of the cooling water used to cool the first battery B1 and the circulation channel of the cooling water used to cool the voltage converter 5 or the power converter 43 are different systems. However, the present invention is not limited to this. Both the voltage converter 5 and the power converter 43, or any one of them, may be cooled by the cooling water used to cool the first battery B1.

[0082] Figure 4 A flowchart illustrating the specific procedure of the power management process is provided. This power management process is repeated at a predetermined cycle in the management ECU 71 from the moment the driver turns on the start switch (not shown) to start the vehicle V and the power system 1, until the driver turns off the start switch to stop the vehicle V and the power system 1.

[0083] First, in step S1, the ECU 71 is managed based on the driver's input to pedals such as the accelerator or brake pedal (see...). Figure 1 The operation amount is calculated to determine the driving torque required by the driver and convert this required driving torque into electricity. The required power Pmot_d of the inverter is then calculated, which is equivalent to the power required by the inverter in the power converter 43, i.e., the required output of the drive motor M. Then, the process moves to step S2.

[0084] Next, in step S2, the management ECU71, based on the demand calculated in step S1, performs the following steps (refer to the section below) via power Pmot_d. Figure 5A and Figure 5BThe target is calculated by power calculation, thereby calculating the target converter power Pcnv_cmd and the target inverter power Pmot_cmd, where the target converter power Pcnv_cmd is equivalent to the target power for the converter and the target inverter power Pmot_cmd is equivalent to the target power for the inverter. Then, the process proceeds to step S3.

[0085] Next, in step S3, the management ECU 71 generates a converter power command signal corresponding to the target converter power Pcnv_cmd and sends it to the converter ECU 73, proceeding to step S8. Thus, the power corresponding to the target converter power Pcnv_cmd is used for charging and discharging from the second battery B2.

[0086] Next, in step S4, the management ECU 71 generates an inverter power command signal corresponding to the target inverter power command Pmot_cmd and sends it to the motor ECU 72. Figure 4 The processing is now complete. Consequently, between the first power circuit 2 and the drive motor M, the power corresponding to the power Pmot_cmd supplied by the target inverter flows. Furthermore, the power obtained by subtracting the power Pcnv_cmd supplied by the target converter from the power Pmot_cmd supplied by the target inverter is used to charge and discharge the first battery B1.

[0087] Figure 5A and Figure 5B A flowchart illustrating the specific procedure for processing the target through power calculations.

[0088] First, in step S11, the management ECU 71 obtains the temperature T1 of the first battery and the temperature T2 of the second battery from the first battery ECU 74 and the second battery ECU 75 respectively, and then proceeds to step S12.

[0089] Next, in step S12, the management ECU 71 obtains the first charge rate SOC1 and the second charge rate SOC2 from the first battery ECU 74 and the second battery ECU 75 respectively, and then proceeds to step S13.

[0090] Next, in step S13, the management ECU71 retrieves a preset chart based on the first battery temperature T1 and the first charge rate SOC1 obtained in steps S11 and S12, and calculates the first allowable output limit P1_lim, which is equivalent to the current upper limit of the allowable output power for the first battery B1, and then proceeds to step S14.

[0091] Next, in step S14, the management ECU71 retrieves a preset chart based on the second battery temperature T2 and the second charge rate SOC2 obtained in steps S11 and S12, and calculates the second allowable output limit P2_lim, which is equivalent to the current upper limit of the allowable output power for the second battery B2, and then proceeds to step S15.

[0092] Next, in step S15, the management ECU 71 determines whether the demand inverter power Pmot_d obtained in step S1 is above the sum of the first allowable output limit P1_lim and the second allowable output limit P2_lim (i.e., the upper limit of the allowable output power for the entire battery including the first battery B1 and the second battery B2). If the determination result in step S15 is yes (YES), the management ECU 71 proceeds to step S16 to implement a limiting process, which limits the demand inverter power Pmot_d to below the sum of the first allowable output limit P1_lim and the second allowable output limit P2_lim, and then proceeds to step S17. More specifically, the management ECU 71 redefines the sum of the first allowable output limit P1_lim and the second allowable output limit P2_lim as the demand inverter power Pmot_d, thereby limiting the demand inverter power Pmot_d. In addition, if the determination result in step S15 is negative (NO), the management ECU71 proceeds to step S17 without implementing the restriction processing in step S16.

[0093] Next, in step S17, the management ECU 71, based on the first battery temperature T1 and the second battery temperature T2 obtained in step S11, retrieves... Figure 6 The illustrated control mode determination table is used to set the battery output control mode corresponding to the current temperature state of the first battery B1 and the second battery B2, and then proceeds to step S20.

[0094] Figure 6 A diagram illustrating an example of a control mode determination table.

[0095] like Figure 6 As shown, the management ECU71 can set the battery output control mode to any one of the first priority output mode, the second priority output mode, and the low-loss battery priority output mode.

[0096] Figure 6In this context, "appropriate temperature" for the first battery B1 means that its temperature T1 is above a specified first temperature standard value T1bs, and "low temperature" for the first battery B1 means that its temperature T1 is below the first temperature standard value T1bs. Similarly, "appropriate temperature" for the second battery B2 means that its temperature T2 is above a specified second temperature standard value T2bs, and "low temperature" for the second battery B2 means that its temperature T2 is below the second temperature standard value T2bs. Here, the first temperature standard value T1bs is set, for example, within the target temperature range where the output characteristics of the first battery B1 are optimal; more specifically, it is set as the lower limit of this target temperature range. Likewise, the second temperature standard value T2bs is set, for example, within the target temperature range where the output characteristics of the second battery B2 are optimal; more specifically, it is set as the lower limit of this target temperature range.

[0097] When the battery output control mode is set to the first priority output mode, the management ECU 71 increases the output power of the first battery B1 to the first allowable output limit P1_lim, prioritizing the second battery B2. That is, when the demand inverter power Pmot_d does not exceed the first allowable output limit P1_lim, the management ECU 71 uses the first battery B1 to provide all the demand inverter power Pmot_d; when the demand inverter power Pmot_d exceeds the first allowable output limit P1_lim, it calculates the target converter power Pcnv_cmd and the target inverter power Pmot_cmd, and uses the second battery B2 to provide the shortfall.

[0098] When the battery output control mode is set to the second priority output mode, the management ECU 71 increases the output power of the second battery B2 to the second allowable output limit P2_lim, prioritizing the first battery B1. That is, when the demand inverter power Pmot_d does not exceed the second allowable output limit P2_lim, the management ECU 71 uses the second battery B2 to provide all the demand inverter power Pmot_d; when the demand inverter power Pmot_d exceeds the second allowable output limit P2_lim, it calculates the target converter power Pcnv_cmd and the target inverter power Pmot_cmd, and uses the first battery B1 to provide the shortfall.

[0099] When the battery output control mode is set to the low-loss battery priority output mode, the ECU71, as explained below, compares the loss generated by the entire power system 1 when the first battery B1 is output first with the loss generated by the entire power system 1 when the second battery B2 is output first, and prioritizes the output of the battery with lower loss.

[0100] according to Figure 6 The illustrated control mode determination table shows that, when the first battery B1 is at a suitable temperature and the second battery B2 is at a low temperature (T1 ≥ T1bs and T2 < T2bs), the management ECU 71 should prioritize outputting power from the first battery B1, which has a suitable temperature and minimal battery loss, thus setting the battery output control mode to the first priority output mode. When the first battery B1 is at a low temperature and the second battery B2 is at a suitable temperature (T1 < T1bs and T2 ≥ T2bs), the management ECU 71 should prioritize outputting power from the second battery B2, which has a suitable temperature and minimal battery loss, thus setting the battery output control mode to the second priority output mode.

[0101] When both battery B1 and battery B2 are at appropriate temperatures (T1≥T1bs and T2≥T2bs), the management ECU 71 sets the battery output control mode to the low-loss battery priority output mode. Conversely, when both battery B1 and battery B2 are at low temperatures (T1<T1bs and T2<T2bs), meaning that using either battery would result in significant losses, power should be prioritized from battery B2, which has a smaller heat capacity and can heat up quickly. Therefore, the battery output control mode is set to the second priority output mode.

[0102] Return to Figure 5B In step S20, the management ECU71 sets the demand inverter via power Pmot_d as the target inverter via power Pmot_cmd, and then proceeds to step S21.

[0103] Next, in step S21, the management ECU 71 determines whether the battery output control mode set in step S17 is a low-loss battery priority output mode. If the determination result of step S21 is no, the management ECU 71 proceeds to step S22.

[0104] In step S22, the management ECU 71 determines whether the battery output control mode set in step S17 is the first priority output mode. If the determination result of step S22 is yes, the management ECU 71 proceeds to step S23.

[0105] In step S23, the management ECU 71 determines whether the power supply Pmot_d of the demand inverter is above the first allowable output limit P1_lim. If the determination result in step S23 is yes, the management ECU 71 proceeds to step S24, where the second battery B2 is used to supplement the insufficient portion of the first battery B1. The value obtained by subtracting the first allowable output limit P1_lim from the power supply Pmot_d of the demand inverter is set as the target converter power supply Pcnv_cmd, and the target power supply calculation process ends. Alternatively, if the determination result in step S23 is no, the management ECU 71 proceeds to step S25, where the value 0 is set as the target converter power supply Pcnv_cmd, and the target power supply calculation process ends.

[0106] Furthermore, if the determination result in step S22 is negative, i.e., the battery output control mode is the second priority output mode, the management ECU 71 proceeds to step S26. In step S26, the management ECU 71 determines whether the power demand of the inverter via Pmot_d is above the second allowable output limit P2_lim. If the determination result in step S26 is positive, the management ECU 71 proceeds to step S27, sets the second allowable output limit P2_lim to the power demand of the target converter via Pcnv_cmd, and the target power calculation process ends. Alternatively, if the determination result in step S26 is negative, the management ECU 71 proceeds to step S28, sets the power demand of the inverter via Pmot_d to the power demand of the target converter via Pcnv_cmd, and the target power calculation process ends.

[0107] In addition, if the determination result of step S21 is yes, that is, if the battery output control mode is the low-loss battery priority output mode, the management ECU71 will proceed to step S29.

[0108] In step S29, the management ECU 71 calculates the first loss Ploss1 and the second loss Ploss2. The first loss Ploss1 corresponds to the loss generated in the first battery B1, the second battery B2 and the voltage converter 5 when the battery output control mode is set to the first priority output control mode. The second loss Ploss2 corresponds to the loss generated in the first battery B1, the second battery B2 and the voltage converter 5 when the battery output control mode is set to the second priority output control mode. Then, the process proceeds to step S30.

[0109] More specifically, the management ECU 71 first obtains the temperature, internal resistance, charging rate, and degradation level of each of the first battery B1 and the second battery B2 from the first battery ECU 74 and the second battery ECU 75. Next, the management ECU 71 calculates the power output from each battery B1 and B2 and the power passing through the voltage converter 5 when the battery output control mode is set to the first priority output control mode. Using the aforementioned power and the obtained temperature, internal resistance, charging rate, and degradation level, it calculates the first loss Ploss1. Furthermore, the management ECU 71 calculates the power output from each battery B1 and B2 and the power passing through the voltage converter 5 when the battery output control mode is set to the second priority output mode. Using the aforementioned power and the obtained temperature, internal resistance, charging rate, and degradation level, it calculates the second loss Ploss2.

[0110] In step S30, the management ECU 71 determines whether the first loss Ploss1 is greater than the second loss Ploss2. If the determination result in step S30 is yes, the management ECU 71 should set the battery output control mode to the second priority output mode with lower loss, and then proceed to step S26. If no, the battery output control mode should be set to the first priority output mode with lower loss, and then proceed to step S23.

[0111] Return to Figure 3 The procedure for controlling the first and second cooling outputs using the cooling circuit ECU76 is explained.

[0112] The cooling circuit ECU76 switches the cooling output control mode for controlling the first and second cooling outputs based on the first battery temperature T1 and the second battery temperature T2. For example... Figure 6 As shown, the cooling circuit ECU76 can independently set the cooling output control mode of the first cooling output and the cooling output control mode of the second cooling output to either the normal mode or the low output mode.

[0113] according to Figure 6 The illustrated control mode determination table shows that when the first battery B1 is at an appropriate temperature (T1 ≥ T1bs), the management ECU 71 sets the cooling output control mode of the first cooling output to normal mode; when the first battery B1 is at a low temperature (T1 < T1bs), the management ECU 71 sets the cooling output control mode of the second cooling output to normal mode; when the second battery B2 is at a low temperature (T2 < T2bs), the management ECU 71 sets the cooling output control mode of the second cooling output to low mode.

[0114] First, let's explain the case where the cooling output control mode is in normal mode.

[0115] When the cooling output control mode of the first cooling output is in normal mode, the cooling circuit ECU76 calculates the first control input (e.g., the duty cycle of the motor driving the cooling fan) for the first cooling device 91 in a manner that the first battery temperature, the value detected by the first coolant temperature sensor, and the value detected by the external air temperature sensor are sent by the first battery ECU74, so that the first battery temperature reaches the first target temperature set within the target temperature range of the first battery B1, and inputs this first control input to the first cooling device 91, thereby controlling the first cooling output.

[0116] In addition, when the cooling output control mode of the second cooling output is in normal mode, the cooling circuit ECU76 calculates a second control input (e.g., the duty cycle of the motor driving the cooling fan) for the second cooling device 92 based on the known second basic cooling algorithm using the second battery temperature sent by the second battery ECU75 and the detection value of the external air temperature sensor, so that the second battery temperature reaches the second target temperature set within the target temperature range of the second battery B2, and inputs this second control input to the second cooling device 92, thereby controlling the second cooling output.

[0117] Next, we will explain the case where the cooling output control mode is in low output mode.

[0118] When the cooling output control mode of the first cooling output is in low output mode, the cooling circuit ECU 76 subtracts a predetermined correction value from the first control input calculated based on the first basic cooling algorithm, thereby correcting the first control input to the direction of reducing cooling performance. This corrected first control input is then input to the first cooling device 91 to control the first cooling output. Therefore, when the first battery B1 is at a low temperature, the cooling circuit ECU 76 reduces the first cooling output compared to a suitable temperature.

[0119] Furthermore, when the cooling output control mode for the second cooling output is in low output mode, the cooling circuit ECU 76 subtracts a predetermined correction value from the second control input calculated based on the aforementioned second basic cooling algorithm, thereby correcting the second control input to a direction that reduces cooling performance. This corrected second control input is then input to the second cooling device 92 to control the second cooling output. Therefore, when the second battery B2 is at a low temperature, the cooling circuit ECU 76 reduces the second cooling output compared to a suitable temperature condition.

[0120] The power supply system 1 according to this embodiment will achieve the following effects.

[0121] (1) In power system 1, management ECU 71 switches the battery output control mode to a first priority output mode or a second priority output mode based on the temperature of the first battery T1 and the temperature of the second battery T2. The first priority output mode increases the output power of the first battery B1 before the second battery B2 to a first allowable output limit P1_lim, and the second priority output mode increases the output power of the second battery B2 before the first battery B1 to a second allowable output limit P2_lim. Therefore, according to power system 1, the battery that is used preferentially can be switched to reduce the circuit losses generated in the entire power system 1. In addition, by reducing circuit losses, the driving range of vehicle V can also be extended.

[0122] (2) When the first battery temperature T1 is less than the first temperature standard value T1bs, the cooling circuit ECU76 reduces the first cooling output of the first cooling device 91 compared to when the first battery temperature T1 is above the first temperature standard value T1bs. When the second battery temperature T2 is less than the second temperature standard value T2bs, the cooling output of the second cooling device 92 reduces the second cooling output compared to when the second battery temperature T2 is above the second temperature standard value T2bs. Thus, while rapidly increasing the first battery temperature T1 and the second battery temperature T2 respectively, the power consumption of the cooling devices 91 and 92 can be suppressed, thereby further extending the driving range of the vehicle V.

[0123] (3) When the temperature of the first battery T1 is above the first temperature standard value T1bs and the temperature of the second battery T2 is below the second temperature standard value T2bs, the management ECU 71 sets the battery output control mode to the first priority output mode, so that the first battery B1 with the appropriate temperature discharges first. This reduces circuit losses compared to the case where the second battery B2 with the lower temperature discharges first. Furthermore, when the temperature of the first battery T1 is below the first temperature standard value T1bs and the temperature of the second battery T2 is above the second temperature standard value T2bs, the management ECU 71 sets the battery output control mode to the second priority output mode, so that the second battery B2 with the appropriate temperature discharges first. This also reduces circuit losses compared to the case where the first battery B1 with the lower temperature discharges first.

[0124] (4) The management ECU 71 acquires the first loss Ploss1 when the battery output control mode is set to the first priority output mode, and the second loss Ploss2 when the battery output control mode is set to the second priority output mode. Furthermore, when the first battery temperature T1 is above the first temperature standard value T1bs and the second battery temperature T2 is above the second temperature standard value T2bs, if the first loss Ploss1 is greater than the second loss Ploss2, the management ECU 71 sets the battery output control mode to the second priority output mode with lower loss; if the second loss Ploss2 is greater than the first loss Ploss1, the battery output control mode is set to the first priority output mode with lower loss. This further reduces circuit losses in the power supply system 1.

[0125] (5) When the temperature of the first battery T1 is less than the first temperature standard value T1bs and the temperature of the second battery T2 is less than the second temperature standard value T2bs, the management ECU71 sets the battery output control mode to the second priority output mode, so that the second battery B2 with smaller heat capacity is discharged first. This enables the second battery B2 to heat up quickly, thus further reducing the circuit loss in the power system 1.

[0126] [Second Implementation]

[0127] Next, the power supply system of the second embodiment of the present invention will be described with reference to the accompanying drawings. The structure of the control mode determination table of the power supply system in this embodiment is different from that of the power supply system 1 in the first embodiment.

[0128] Figure 7 This diagram illustrates an example of a control mode determination table used as a reference in the power supply system of this embodiment. Figure 7 The control mode determination table shown above, regarding the battery output control mode when both battery 1 (B1) and battery 2 (B2) are at appropriate temperatures, is consistent with... Figure 6 The control mode determination table shown is different.

[0129] according to Figure 7 The illustrated control mode determination table shows that when both the first battery B1 and the second battery B2 are at appropriate temperatures (T1≥T1bs and T2≥T2bs), the battery output control mode is set to the first priority output mode.

[0130] The power supply system according to this embodiment will achieve the following effects.

[0131] (6) In the power supply system, the first battery B1 is connected to the drive motor M via power converter 43, and the second battery B2 is connected to the drive motor M via power converter 43 and voltage converter 5. Therefore, assuming that the circuit loss in the first battery B1 is equal to the circuit loss in the second battery B2, in the second priority output mode, more power passes through the voltage converter 5 than in the first priority output mode, so the loss in the second priority output mode is greater than that in the first priority output mode. Therefore, the management ECU sets the battery output control mode to the first priority output mode with lower loss when the temperature T1 of the first battery is above the first temperature standard value T1bs and the temperature T2 of the second battery is above the second temperature standard value T2bs. This can further reduce the circuit loss in the power supply system.

[0132] The above description illustrates one embodiment of the present invention, but the invention is not limited thereto. Appropriate modifications to the local structure are possible within the scope of the invention.

[0133] Figure Labels

[0134] V: Vehicle (moving entity)

[0135] M: Drive motor (rotary electric motor)

[0136] 1: Power System

[0137] 2: First power circuit (power circuit)

[0138] B1: First battery (first energy storage device)

[0139] 3: Second power circuit (power circuit)

[0140] B2: Second battery (second energy storage device)

[0141] 4: Load circuit

[0142] 43: Power Converter

[0143] 5: Voltage converter

[0144] 7: Electronic Control Unit Group

[0145] 71: ECU Management (Power Control Methods, Permissible Output Limit Acquisition Methods, Loss Acquisition Methods)

[0146] 72: Motor ECU (Electric Control Unit)

[0147] 73: Converter ECU (Electrical Control Unit)

[0148] 74: Battery ECU (Temperature acquisition method, Allowable output limit acquisition method)

[0149] 75: Second Battery ECU (Temperature Acquisition Method, Permissible Output Limit Acquisition Method)

[0150] 76: Cooling circuit ECU (cooling output control mechanism)

[0151] 81: First battery sensor unit (temperature acquisition method, permissible output upper limit acquisition method)

[0152] 82: Second battery sensor unit (temperature acquisition method, permissible output upper limit acquisition method)

[0153] 9: Cooling circuit

[0154] 91: First Cooling Unit

[0155] 92: Second Cooling Unit

Claims

1. A power supply system, comprising: First energy storage device; Second energy storage device; A load circuit, which includes a rotating motor; A power circuit that connects the first and second energy storage devices to the load circuit; The power control means controls the output power of the first and second energy storage devices by operating the power circuit; A cooling circuit that cools the first energy storage device and the second energy storage device; and, A cooling output control means that controls the first cooling output of the cooling circuit for the first energy storage device and the second cooling output of the cooling circuit for the second energy storage device; The power supply system is characterized by having: A temperature acquisition method that acquires the temperature of the first energy storage device, i.e., a first temperature, and the temperature of the second energy storage device, i.e., a second temperature; and, The means for obtaining the permissible output limit is to obtain a first permissible output limit for the output power of the first energy storage device and a second permissible output limit for the output power of the second energy storage device. Furthermore, the power control method, based on the first and second temperatures, switches the control mode to a first priority output mode or a second priority output mode. The first priority output mode increases the output power of the first energy storage device to the first permissible output limit before the second energy storage device. The second priority output mode increases the output power of the second energy storage device to the second permissible output limit before the first energy storage device. Furthermore, the cooling output control means reduces the first cooling output when the first temperature is less than the first temperature standard value compared to when the first temperature is above the first temperature standard value, and reduces the second cooling output when the second temperature is less than the second temperature standard value compared to when the second temperature is above the second temperature standard value.

2. A power supply system, comprising: First energy storage device; Second energy storage device; A load circuit, which includes a rotating motor; A power circuit that connects the first and second energy storage devices to the load circuit; The power control means controls the output power of the first and second energy storage devices by operating the power circuit; The power supply system is characterized by having: A temperature acquisition method that acquires the temperature of the first energy storage device, i.e., a first temperature, and the temperature of the second energy storage device, i.e., a second temperature; and, The means for obtaining the permissible output limit is to obtain a first permissible output limit for the output power of the first energy storage device and a second permissible output limit for the output power of the second energy storage device. The power control method, based on the first and second temperatures, switches the control mode to a first priority output mode or a second priority output mode. The first priority output mode increases the output power of the first energy storage device before the second energy storage device, up to the first permissible output limit. The second priority output mode increases the output power of the second energy storage device before the first energy storage device, up to the second permissible output limit. The power control means sets the control mode to the first priority output mode when the first temperature is above the first temperature standard value and the second temperature is below the second temperature standard value, and sets the control mode to the second priority output mode when the first temperature is below the first temperature standard value and the second temperature is above the second temperature standard value.

3. The power supply system according to claim 2, characterized in that: It also has loss acquisition means, which acquires a first loss and a second loss. The first loss is the loss generated by the first energy storage device and the power circuit when the control mode is set to the first priority output mode, and the second loss is the loss generated by the second energy storage device and the power circuit when the control mode is set to the second priority output mode. Furthermore, when the first temperature is above the first temperature standard value and the second temperature is above the second temperature standard value, and the first loss is greater than the second loss, the power control means sets the control mode to the second priority output mode; when the second loss is greater than the first loss, the control mode is set to the first priority output mode.

4. The power supply system according to claim 2, characterized in that... It also has: A first power circuit having the first energy storage device; A second power circuit having the second energy storage device; A voltage converter that transforms voltage between the first power circuit and the second power circuit; as well as, A power converter that connects the first power circuit to the rotating motor; Furthermore, the power control means sets the control mode to the first priority output mode when the first temperature is above the first temperature standard value and the second temperature is above the second temperature standard value.

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

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