Power supply system

Abstract

The present invention provides a power supply system that can continuously supply the remaining power of multiple battery units to the power grid as much as possible, or that can continuously charge multiple battery units from the power grid. [Solution] A power supply system for supplying power to a power grid, comprising a battery unit 5 having a battery 16, a converter 17 provided between the battery 16 and the power grid or other power grid to increase or decrease the voltage output from the battery 16, control units 11 and 12 that control the converter 17, and a DC-DC converter 15 connected to the battery 16 that increases or decreases the voltage of the battery 16 and outputs it, and an auxiliary battery 10 that outputs power to operate the control units 11 and 12 and stores the power supplied from the DC-DC converter 15, wherein a plurality of battery units 5 are connected in parallel.

Description

Technical Field

[0001] This invention relates to a power supply system composed of a plurality of battery units.

Background Art

[0002] Patent Document 1 describes a stationary battery device that reuses a plurality of vehicle driving batteries. Each of these driving batteries includes a battery unit for storing power, an acceleration sensor, a voltage sensor, a current sensor, a temperature sensor, a storage unit, a control unit, etc., and each battery is connected to the power grid via a DC-DC converter, a power conditioner, and a relay.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The control unit and DC-DC converter provided in the battery device described in Patent Document 1 usually operate by being supplied with power from a low-voltage power source. Therefore, when the power of the constant-voltage power source decreases and the control unit and DC-DC converter cannot be operated, there is a possibility that power cannot be supplied to the power grid even though sufficient power remains in the battery unit.

[0005] This invention is made by focusing on the above technical problems, and the object of this invention is to provide a power supply system that can continuously supply the remaining power of a plurality of battery units to the power grid as much as possible, or continuously charge a plurality of battery units from the power grid.

Means for Solving the Problems

[0006] To achieve the above objective, this invention provides a power supply system for supplying power to a power system or storing power supplied from the power system or other power systems, comprising: a battery; a battery unit having a battery; a converter provided between the battery and the power system or other power system for increasing or decreasing the voltage output from the battery or the voltage input to the battery; a control unit for controlling the converter; a DC-DC converter connected to the battery and outputting the voltage of the battery; and an auxiliary battery that outputs power to operate the control unit and stores power supplied from the DC-DC converter, wherein a plurality of the battery units are connected in parallel.

[0007] Furthermore, in this invention, the system control unit further comprises a system control unit that outputs a command signal to the control unit in the battery unit, and the system control unit may output a command signal to the control unit provided in the faulty battery unit to cut off the power supply between the battery, the converter and the DC-DC converter in the faulty battery unit when any of the battery units among the plurality of battery units fails.

[0008] Furthermore, this invention includes a system control unit that operates when power is supplied from a commercial power source, and the system control unit may be configured to output a command signal to the control unit in the battery unit to operate the converter.

[0009] Furthermore, in this invention, the system control unit may be connected to an uninterruptible power supply (UPS) that continues to supply power to the system control unit when power cannot be supplied to the system control unit from the commercial power supply.

[0010] Furthermore, in this invention, at least one of the battery, the converter, the control unit, and the DC-DC converter may be configured by reusing the battery, the converter, the control unit, and the DC-DC converter that were installed in an electric vehicle. [Effects of the Invention]

[0011] The power supply system in this invention comprises a battery unit having a battery, a converter provided between the battery and a power system or other power system that increases or decreases the voltage output from the battery or the voltage input to the battery, a control unit that controls the converter, a DC-DC converter connected to the battery that increases or decreases the battery voltage and outputs it, and an auxiliary battery that outputs power to operate the control unit and stores the power supplied from the DC-DC converter, with multiple battery units connected in parallel. Therefore, even if any one of the battery units fails, power can continue to be supplied from the other battery units to the control units provided in each battery unit. In other words, power can continue to be output to the power system, or power can continue to be charged in the power system or other power systems. That is, it can continue to function as a battery device. Furthermore, because power can be supplied from each battery unit to the control unit provided in each battery unit in this way, the capacity of the auxiliary battery can be reduced, and the size of the power supply system can be suppressed. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 is a diagram illustrating an example of a power supply system in an embodiment of the present invention. [Figure 2] Figure 2 is a diagram illustrating an example of a battery module. [Figure 3] Figure 3 is a flowchart illustrating an example of the control performed by the system ECU when any battery unit fails. [Figure 4]Figure 4 is a flowchart illustrating an example of the control performed by the system ECU in the event of a power outage. [Modes for carrying out the invention]

[0013] This invention will be described based on the embodiments shown in the figures. The embodiments described below are merely examples of how this invention can be implemented and do not limit it.

[0014] An example of a power supply system in an embodiment of this invention is schematically shown in Figure 1. The power supply system 1 shown in Figure 1 comprises a system control unit 2, a battery device 3, and a power conditioner 4 as an input / output unit.

[0015] The system control unit 2 is configured to output a command signal that either activates the battery device 3 or prohibits the output of power from any of the battery units 5 provided in the battery device 3 (described later). This system control unit 2 consists of a system ECU 6, a stabilized power supply 7, and an uninterruptible power supply 8.

[0016] The system ECU 6 is an electronic control unit mainly composed of a microcomputer, and is configured to determine a command signal to be output to the battery device 3 based on the input signal and pre-stored maps and calculation formulas. Specifically, for example, if it receives a signal that the battery unit 5 has failed from the ECUs 11, 12, and 13 located in the battery device 3 (described later), it outputs a command signal to prohibit the output of power from the battery unit 5. Also, for example, if the power grid connected to the power supply system 1 is configured to be supplied with power from another power source such as commercial power, and the power conditioner 4 inputs information about a power outage where power is not supplied to the power grid from that other power source such as commercial power, it outputs a command signal to supply power from the battery device 3 to the power grid. Note that in Figure 1, communication lines are shown with double lines.

[0017] The system ECU 6 described above operates by receiving power from a commercial power supply or similar source. Therefore, a stabilized power supply 7 is provided between the system ECU 6 and a commercial power supply (not shown) to rectify the voltage input from the commercial power supply and output it as the operating voltage for the system ECU 6.

[0018] Furthermore, an uninterruptible power supply (UPS) 8 is connected between the stabilized power supply 7 and the system ECU 6 so that the system ECU 6 can operate even in the event of a power outage where power is not supplied to the power system from the commercial power supply. In other words, if a power outage occurs and power is not input to the stabilized power supply 7 from the commercial power supply, and the stabilized power supply 7 cannot supply power to the system ECU 6, the system ECU 6 can continue to operate by supplying power from the UPS 8.

[0019] The battery device 3 comprises multiple battery modules 9, each having multiple battery units 5, and these battery modules 9 are connected in parallel. Power is supplied to each battery module 9 from the auxiliary battery 10, and this power is supplied to the EV-ECU 11, MG-ECU 12, battery ECU 13, and system main relay (SMR) 14, which will be described later. Furthermore, the power output from each battery unit 5 is supplied to the auxiliary battery 10 via the DC-DC converter 15, which will be described later, meaning that each battery unit 5 can individually charge the auxiliary battery 10. In addition, each battery module 9 is electrically connected to the power conditioner 4. Note that in Figure 1, relatively low-voltage power lines are shown with thin lines, and relatively high-voltage power lines are shown with thick lines.

[0020] The power conditioner 4 converts the DC voltage input from the battery device 3 into an AC voltage and outputs it to a power grid (not shown). Also, it converts the AC voltage input from another power grid such as the power grid or a power generation device (not shown) into a DC voltage and supplies it to the battery device 3 to charge the battery device 3. For example, when power is not supplied from a commercial power source or the like to the power grid of the power supply destination due to a power outage or the like, the power conditioner 4 outputs a signal indicating the power outage to the system ECU 6.

[0021] FIG. 2 shows a diagram for explaining an example of the battery module 9 described above. As shown in FIG. 2, the battery module 9 is configured by connecting three battery units 5 in parallel. Those battery units 5 are those obtained by reusing a battery unit provided as a traveling battery for a moving body such as a vehicle, and include a high-voltage battery 16, a boost circuit 17, a DCDC converter 15, an SMR 14, an EV-ECU 11, an MG-ECU 12, and a battery ECU 13.

[0022] The high-voltage battery 16 is, for example, a battery obtained by reusing a traveling battery for a moving body such as an electric vehicle or a hybrid vehicle, and is composed of a secondary battery such as a lithium-ion battery or a nickel-hydrogen battery, or a secondary battery such as an electric double-layer capacitor. Note that the high-voltage battery 16 may be a battery pack in which the above secondary batteries are connected in series. This high-voltage battery 16 corresponds to the "battery" in the embodiment of this invention.

[0023] The boost circuit 17 is configured to boost the voltage of the high-voltage battery 16 and output it to the power conditioner 4, and also to step down the voltage input from the power conditioner 4 and output it to the high-voltage battery 16. That is, the boost circuit 17 functions as a converter. This boost circuit 17 reuses a converter provided in a power control unit of an electric vehicle or a hybrid vehicle. This boost circuit 17 corresponds to the "converter" in the embodiment of this invention.

[0024] The DC-DC converter 15 is configured to step down the voltage of the high-voltage battery 16. This DC-DC converter 15 reuses a DC-DC converter that was originally installed to step down the output voltage of the traction battery when supplying power from the traction battery to auxiliary equipment such as lighting installed in the vehicle, or to a low-voltage auxiliary battery.

[0025] SMR14 is a relay configured to electrically connect or disconnect the high-voltage battery 16 and the boost circuit 17 and DC-DC converter 15, and reuses a relay that selectively connects or disconnects the vehicle's traction battery and converter. Specifically, it includes a solenoid (not shown), and is configured to connect the high-voltage battery 16 and the boost circuit 17 and DC-DC converter 15 by supplying power from the auxiliary battery 10 to the solenoid.

[0026] The EV-ECU11 is an electronic control unit configured to operate when power is supplied from the auxiliary battery 10, and is configured to output command signals to the MG-ECU12 and the battery ECU13. The EV-ECU11 is mainly composed of a microcomputer and outputs command signals to the MG-ECU12 and the battery ECU13 based on the input signals. Specifically, for example, when the system ECU6 receives a signal to output power from the battery unit 5, it outputs a command signal to the battery ECU13 to connect the high-voltage battery 16 to the boost circuit 17 and the DC-DC converter 15, and outputs a command signal to the MG-ECU12 to boost the output voltage of the high-voltage battery 16 to the required voltage. Alternatively, when the system ECU6 receives a signal to charge the battery unit 5, it outputs a command signal to the battery ECU13 to connect the high-voltage battery 16 to the boost circuit 17 and the DC-DC converter 15, and outputs a command signal to the MG-ECU12 to step down the voltage to the required voltage for charging the high-voltage battery 16.

[0027] Furthermore, if the EV-ECU11 is unable to properly control the battery unit 5 due to a break in a component of the battery unit 5 or a break in its communication line (power line), it outputs a signal to the system ECU6. The system ECU6 then determines which battery unit 5 has failed and outputs a command signal to the EV-ECU11 to shut off the SMR14.

[0028] The EV-ECU11 is a controller that was installed in the vehicle. For example, when controlling the motor as the driving force source of the vehicle, it is a controller that determines the command signal for whether or not to connect the traction battery and the power control unit, and the command signal for the voltage value to be boosted or lowered by the power control unit. In other words, it is installed in the vehicle together with the MG-ECU12 and battery ECU13, and the configuration for exchanging signals with the MG-ECU12 and battery ECU13 is reused in the same configuration as when it was installed in the vehicle.

[0029] The MG-ECU12 is a controller for controlling the boost circuit 17. Specifically, it is configured to determine the gate signals (power) of the switching elements (not shown) that make up the boost circuit 17 based on command signals for boosting the output voltage of the high-voltage battery 16 and command signals for stepping down the voltage to the voltage required to charge the high-voltage battery 16, and to output the determined gate signals to the boost circuit 17. Like the EV-ECU11, the MG-ECU12 also operates when power is supplied from the auxiliary battery 10, and is configured to output the gate signals (power) of the boost circuit 17 based on that power.

[0030] The battery ECU 13 is a controller for controlling the SMR 14 and the DC-DC converter 15. Specifically, when a command signal to output power from the high-voltage battery 16 or to charge the high-voltage battery 16 is input from the EV-ECU 11, the battery ECU 13 outputs power to the SMR 14 to put it into a conductive state (connected state). When the battery unit 5 fails and the battery ECU 13 receives a command signal from the EV-ECU 11 to put the SMR 14 into a disconnected state, the battery ECU 13 outputs a signal to put the SMR 14 into a disconnected state, that is, a signal to cut off the power supplied to the SMR 14 from the auxiliary battery 10. The EV-ECU 11, MG-ECU 12, and battery ECU 13 described above may be a single ECU configured as an integrated unit, and these ECUs 11, 12, and 13 correspond to the "control unit" in the embodiment of this invention.

[0031] Furthermore, when charging the auxiliary battery 10, or when supplying power to each ECU 11, 12, 13 after the power supply system 1 has started up, a gate signal (power) is output to a switching element (not shown) provided in the DC-DC converter 15 so that the voltage output from the battery device 3 via the DC-DC converter 15 becomes a predetermined voltage.

[0032] Figure 3 shows a flowchart illustrating an example of control performed by the system ECU 11 when any of the battery units 5 fail. In this control example, first, it is determined whether or not there is a system start request (step S1). Step S1 can determine that there is a system start request if, for example, the operating switch of the power system 1 is turned on, there is a request from the battery device 3 to output power to the power system, or there is a request from the power system or another power system such as a generator to charge the battery device 3. Specifically, for example, it can be determined that there is a system start request if the applied voltage of the power system is below the target voltage, or if the output voltage of the battery device 3, in other words, the voltage applied to the power conditioner 4, is below a predetermined voltage, or if the power input to the power conditioner 4 from the power system or other power systems is above a predetermined power.

[0033] If step S1 is negatively determined due to the absence of a system startup request, this routine is terminated. Conversely, if step S1 is positively determined due to a system startup request, a command signal is output to the EV-ECU 11 to supply power from the auxiliary battery 10 to the battery device 3 and start the respective ECUs 11, 12, and 13 located in each battery unit 5 (step S2). This starts the battery device 3. In other words, the battery device 3 becomes capable of outputting power to the power system and supplying power to the auxiliary battery 10 or the ECUs 11, 12, and 13 located in the battery device 3 via the DC-DC converter 15.

[0034] Next, a command signal to output power from each DCDC converter 15 is output to the battery ECU 13 (step S3). That is, power is supplied from the DCDC converter 15 to each ECU 11, 12, and 13. Specifically, the SMR 14 is switched to a conductive state, and the DCDC converter 15 is controlled so that the voltage output from the battery device 3 by the DCDC converter 15 becomes the operating voltage for each ECU 11, 12, and 13. As a result, each ECU 11, 12, and 13 can operate with the power supplied from each high-voltage battery 16, and the power of the auxiliary battery 10 is not consumed.

[0035] Next, it is determined whether or not any of the battery units 5 have failed (step S4). This step S4 can be determined based on the signals input from the EV-ECU 11 provided in each battery unit 5 to the system ECU 6.

[0036] If step S4 is negatively determined because none of the battery units 5 are faulty, step S4 is repeated. That is, power is supplied from each DCDC converter 15 to each ECU 11, 12, and 13 to keep the battery device 3 running. Conversely, if step S4 is positively determined because any of the battery units 5 have failed, the faulty battery unit 5 is degraded (step S5). That is, a command signal is output to the EV-ECU 11 provided in the faulty battery unit 5 to switch the SMR 14 in that battery unit 5 to a shut-off state. In other words, the power output from the faulty battery unit 5 is stopped.

[0037] Then, power is continuously supplied from the DC-DC converters 15 located in the other battery units (normal battery units) 5, excluding the faulty battery unit 5, to each of the ECUs 11, 12, and 13 located in all of the battery units 5, including the ECUs 11, 12, and 13 located in the faulty battery unit 5 (step S6), and this routine is completed.

[0038] Figure 4 shows a flowchart illustrating an example of control performed by the system ECU6 in the event of a power outage. Steps identical to those shown in the control example in Figure 3 are given the same step numbers and their explanations are omitted.

[0039] After supplying power from each high-voltage battery 16 to each ECU 11, 12, and 13 and operating them, it is determined whether or not a power outage has occurred in which power is not supplied to the power grid from another power source such as commercial power (step S11). This step S11 can be determined by detecting the signal input from the power conditioner 4 to the system ECU 6 or the input voltage of the stabilized power supply 7.

[0040] If step S11 is negatively determined because no power outage has occurred, step S11 is repeated. That is, power is supplied from each DCDC converter 15 to each ECU 11, 12, 13 to keep the battery unit 3 running. Conversely, if step S11 is positively determined because a power outage has occurred, power is supplied from the DCDC converters 15 in all battery units 5 to each ECU 11, 12, 13 in each battery unit 5 (step S12). Then, after the power of the high-voltage batteries 16 in all battery units 5 has been used up, power is supplied from the auxiliary battery 10 to each ECU 11, 12, 13 in all battery units 5 (step S13), and this routine ends. That is, all ECUs 11, 12, 13 are kept running until the power of the auxiliary battery 10 has been used up.

[0041] As described above, by connecting each battery unit 5 in parallel and providing a DC-DC converter 15 for each battery unit 5, even if one of the battery units 5 fails, power can continue to be supplied from the other battery units 5 to the ECUs 11, 12, and 13 installed in each battery unit 5. In other words, the battery device 3 can continue to output power to the power system, or the power system or other power systems can supply power to the battery device 3 to continue charging, meaning that the battery device 3 can continue to function. Furthermore, because power can be supplied from each battery unit 5 to the ECUs 11, 12, and 13 installed in each battery unit 5 in this way, the capacity of the auxiliary battery 10 can be reduced, and the size of the power supply system 1 can be suppressed.

[0042] Furthermore, in electric vehicles, the load on the high-voltage battery and boost circuit changes significantly due to the relatively instantaneous changes in the driver's operation and the surrounding environment, leading to rapid deterioration of the high-voltage battery and boost circuit. Also, because of these large load changes, even if steady-state operation with small load changes is possible, the high-voltage battery and boost circuit cannot be used as the vehicle's power supply system in order to maintain their reliability. Therefore, by reusing the high-voltage battery 16 and boost circuit 17 that were installed in the vehicle to construct each battery unit 5, it is possible to reduce the cost of the power supply system 1 and contribute to environmental protection.

[0043] Furthermore, when using multiple battery units 5 that reuse high-voltage batteries 16 and boost circuits 17 that were installed in the vehicle, as described above, there will be variations in the degree of deterioration among the battery units 5, resulting in variations in their usable period. Therefore, by configuring the system so that other battery units 5 can be used independently even if one of the battery units 5 fails, as described above, the opportunities for the battery device 3 to become unusable due to maintenance or parts replacement can be reduced.

[0044] Furthermore, if any of the battery units 5 fail, by continuing to supply power to each of the ECUs 11, 12, and 13 provided in all battery units 5, including the failed battery unit 5, it is possible to prevent the erasure of diagnostic information stored in the ECUs 11, 12, and 13 provided in the failed battery unit 5. This allows for the acquisition of diagnostic information during maintenance, which contributes to identifying faulty parts and determining the cause of the failure.

[0045] Furthermore, even during a power outage, each DC-DC converter 15 can supply power to each ECU 11, 12, and 13, allowing them to continue operating. Therefore, the uninterruptible power supply 8 only needs to keep the system ECU 6 running, which helps to prevent the uninterruptible power supply 8 from becoming larger, and thus helps to prevent the power supply system 1 from becoming larger or more expensive. [Explanation of Symbols]

[0046] 1. Power System 2. System Control Unit 3. Battery device 4 Power Conditioner 5 Battery Unit 6 System ECU 7 Stabilized power supply 8 Uninterruptible power supply (UPS) 9 Battery Modules 10. Auxiliary battery 11 EV-ECU 12 MG-ECU 13 Battery ECU 14. System Main Relay (SMR) 15 DC-DC converters 16 High-voltage batteries 17 Boost Circuit

Claims

1. A power supply system that supplies power to a power grid or stores power supplied from the said power grid or other power grids, A battery unit comprising: a battery; a converter provided between the battery and the power system or the other power system for increasing or decreasing the voltage output from the battery or the voltage input to the battery; a control unit for controlling the converter; and a DC-DC converter connected to the battery for increasing or decreasing the battery's voltage and outputting it. The system includes an auxiliary battery that outputs power to operate the control unit and stores power supplied from the DC-DC converter, Multiple battery units are connected in parallel. A power supply system characterized by the following features.

2. A power supply system according to claim 1, The battery unit further comprises a system control unit that outputs a command signal to the control unit, The system control unit outputs a command signal to the control unit provided in the faulty battery unit to cut off power to the battery, the converter, and the DC-DC converter in the faulty battery unit if any of the battery units fail. A power supply system characterized by the following features.

3. A power supply system according to claim 1, It has a system control unit that operates by being powered by commercial power, The system control unit is configured to output a command signal to operate the converter to the control unit in the battery unit. A power supply system characterized by the following features.

4. A power supply system according to claim 3, The system control unit is connected to an uninterruptible power supply (UPS) that continues to supply power to the system control unit when power cannot be supplied to the system control unit from the commercial power supply. A power supply system characterized by the following features.

5. A power supply system according to any one of claims 1 to 4, At least one of the battery, converter, control unit, and DC-DC converter is configured by reusing the battery, converter, control unit, and DC-DC converter that were installed in an electric vehicle. A power supply system characterized by the following features.

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