Power device and control method thereof

Abstract

To avoid an occurrence of excess current and a state where no power is transmitted by a simple configuration and at low costs.SOLUTION: In a power device 10 and a control method thereof, by bringing an intermittent part 16 arranged on one power transmission path 14 among a plurality of power transmission paths 14 into a connection state, power is transmitted through the intermittent part 16 arranged on one power transmission path 14 in series and a one-direction rectification part 18. Then, by bringing an intermittent part 16 arranged on the other power transmission path 14 into the connection state, power is transmitted through the intermittent part 16 arranged on the other power transmission path 14 in series and the one-direction rectification part 18. Subsequently, the intermittent part 16 arranged on the one power transmission path 14 is brought into a cut-off state.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a power device in which a plurality of power storage units are connected in parallel to a connection unit via a plurality of power transmission paths, and a control method thereof. [Background technology]

[0002] Patent Document 1 discloses that when a main power supply provided in a vehicle and multiple auxiliary power supplies that are detachable from the vehicle are connected in parallel to a drive device such as a motor, power is output from an auxiliary power supply with a higher output voltage, or power is output in parallel from the multiple auxiliary power supplies. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-175864 A Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, the auxiliary power supply and the drive device are connected by turning on a switch built into the auxiliary power supply, and power is output from the auxiliary power supply to the drive device. Alternatively, the auxiliary power supply and the drive device are connected by controlling a converter and a switch provided in a power transmission path connecting the auxiliary power supply and the drive device, and power is output from the auxiliary power supply to the drive device.

[0005] However, because multiple auxiliary power sources are connected in parallel to the drive unit, if the switch is turned on while an auxiliary power source that has run out of power is connected to the drive unit, and a fully charged auxiliary power source is connected to the drive unit, there is a possibility that a circulating current, which is an overcurrent, will flow from the fully charged auxiliary power source to the auxiliary power source that has run out of power.

[0006] One way to avoid such an overcurrent is to turn off the switch on the auxiliary power supply when the auxiliary power supply discharges and runs out of power, and then turn on the switch on the fully charged auxiliary power supply. However, during the time period from when the switch on the auxiliary power supply that runs out of power is turned off to when the switch on the fully charged auxiliary power supply is turned on, no power is output to the drive device, making it difficult to drive the vehicle properly.

[0007] On the other hand, when a converter is provided, the same number of converters as the number of auxiliary power supplies are required, which increases costs and complicates control.

[0008] The present invention has been made in consideration of such problems, and aims to provide a power device and a control method thereof that can avoid the occurrence of overcurrent and a state in which power is not transmitted, with a simple configuration and at low cost. [Means for solving the problem]

[0009] A first aspect of the present invention is a power device having a plurality of power storage units, a plurality of power transmission paths connected to a plurality of the power storage units, and a connection unit that connects the plurality of power storage units in parallel via the plurality of power transmission paths, and has a one-way rectifier unit arranged in a plurality of the power transmission paths, and an interruption unit arranged in series with the one-way rectifier units in the plurality of power transmission paths, connecting and disconnecting the power storage units and the connection unit.

[0010] A second aspect of the present invention is a power device having a plurality of power storage units, a plurality of power transmission paths connected to a plurality of the power storage units, and a connection portion connecting the plurality of the power storage units in parallel via the plurality of power transmission paths, the power device having a plurality of first power transmission paths constituting the plurality of power transmission paths and connecting the plurality of the power storage units and the connection portion, a first interruption portion arranged on the plurality of first power transmission paths and connecting the power storage units and the connection portion, a plurality of second power transmission paths constituting the plurality of power transmission paths and connecting a portion of the first power transmission paths closer to the power storage units than the first interruption portion to the connection portion and connecting portions on the connection portion side to each other, a second interruption portion arranged on the plurality of second power transmission paths and connecting the power storage units and the connection portion, and a one-way rectification portion arranged between a portion of the plurality of second power transmission paths on the connection portion side and the connection portion.

[0011] A third aspect of the present invention is a control method for a power device in which a plurality of power storage units are connected in parallel to a connection unit via a plurality of power transmission paths, comprising the steps of: transmitting power through an interrupter unit and a one-way rectifier unit arranged in series in one of the plurality of power transmission paths by setting an interrupter unit arranged in one of the plurality of power transmission paths to a connected state; transmitting power through the interrupter unit and a one-way rectifier unit arranged in series in the other power transmission path by setting an interrupter unit arranged in the other power transmission path to a connected state; and setting the interrupter unit arranged in the one of the power transmission paths to a disconnected state.

[0012] A fourth aspect of the present invention is a control method for a power device in which a plurality of power storage units are connected in parallel to a connection unit via a plurality of power transmission paths, the plurality of power transmission paths being configured with a plurality of first power transmission paths connecting the plurality of power storage units to the connection unit and including a first interruption unit that connects the power storage units to the connection unit and disconnects the power storage units from the connection unit, and a plurality of second power transmission paths connecting a portion of the first power transmission paths closer to the power storage units than the first interruption unit and the connection unit, the portions of the first power transmission paths being connected to the connection unit, and including a second interruption unit that connects the power storage units to the connection unit and disconnects the power storage units from the connection unit, When a one-way rectifier is arranged between the connection portion side of the power transmission path and the connection portion, and the power device has a plurality of groups each consisting of the first power transmission path, the first interruption portion, the second power transmission path, and the second interruption portion, the method includes a step of setting the first interruption portion of one of the groups to a connected state, a step of setting the second interruption portion of one of the groups to a connected state, a step of setting the first interruption portion of one of the groups to a disconnected state, a step of setting the first interruption portion of the other group to a connected state, and a step of setting the second interruption portion of one of the groups to a disconnected state. Effect of the Invention

[0013] According to the present invention, a one-way rectifier is provided in the power transmission path, so that even if the interrupted parts of the multiple power transmission paths are connected, it is possible to prevent a circulating current, which is an overcurrent, from flowing around from a fully charged storage unit to a storage unit in an out-of-power state. Furthermore, by connecting the interrupted parts of the multiple power transmission paths, power is output from the fully charged storage unit via the connection part. This makes it possible to avoid the occurrence of a time period during which voltage is not transmitted (output) (a time period during which power supply to a load is interrupted). Furthermore, since it is a simple configuration in which the interrupted parts and the one-way rectifier are arranged in series in the power transmission path, it is inexpensive and easy to control. [Brief description of the drawings]

[0014] [Figure 1] 1 is a configuration diagram of a power device according to a first embodiment. [Diagram 2] 2 is a configuration diagram showing details of a power storage unit in FIG. 1. [Diagram 3] FIG. 1 is a schematic explanatory diagram of a power device of a comparative example. [Figure 4] FIG. 4A is an explanatory diagram of a case where one discontinuous portion in FIG. 3 is in a connected state, and FIG. 4B is an explanatory diagram of a case where two discontinuous portions in FIG. 3 are in a connected state. [Diagram 5] FIG. 5A is an explanatory diagram of when the interrupting unit on the side of the power-depleted storage unit is switched to a disconnected state, and FIG. 5B is an explanatory diagram of when the other interrupting unit is switched from the state of FIG. 5A to a connected state. [Figure 6] FIG. 6A is a schematic explanatory diagram of the power device according to the first embodiment, and FIG. 6B is an explanatory diagram of a case where one discontinuous portion in FIG. 6A is in a connected state. [Figure 7] FIG. 7A is an explanatory diagram of the case where two interrupting units are in a connected state, and FIG. 7B is an explanatory diagram of the case where the interrupting unit on the side of the power-depleted storage unit is switched to an interrupted state. [Figure 8] 5 is a flowchart showing a connection process of a power device according to the first embodiment. [Figure 9] 9A is an explanatory diagram of the processes in steps S1 and S2 in FIG. 8, and FIG. 9B is an explanatory diagram of the process in step S7 in FIG. [Figure 10] 10A is an explanatory diagram of the process of step S8 in FIG. 8, and FIG. 10B is an explanatory diagram of the process of step S9 in FIG. [Figure 11] 10 is a flowchart showing another connection process of the power device according to the first embodiment. [Figure 12] FIG. 11 is a configuration diagram of a power device according to a second embodiment. [Figure 13] FIG. 13A is a schematic explanatory diagram of the power device in FIG. 12, and FIG. 13B is an explanatory diagram of a case where one first intermittent portion in FIG. 13A is in a connected state. [Figure 14] FIG. 14A is an explanatory diagram when one second interrupting unit is switched to a connected state, and FIG. 14B is an explanatory diagram when a first interrupting unit on the side of a power-depleted storage unit is switched to a disconnected state. [Figure 15]FIG. 15A is an explanatory diagram of when the first interrupter on the fully charged storage unit side is switched to the connected state, and FIG. 15B is an explanatory diagram of when the second interrupter on the out-of-power storage unit side is switched to the disconnected state. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of a power device and a control method thereof according to the present invention will be described with reference to the accompanying drawings.

[0016] [1. Schematic configuration of the first embodiment] 1, a power device 10 according to a first embodiment of the present invention includes a plurality of power storage units 12, a plurality of power transmission paths 14, a plurality of interrupting units 16, a plurality of one-way rectifying units 18, a connection unit 20, and an ECU (Electronic Control Unit) 22. The power device 10 is applied to a power supply system of an electric vehicle 24, such as a unicycle, a two-wheeled vehicle, or a four-wheeled vehicle, for example.

[0017] The first embodiment is applicable not only to the electric vehicle 24 but also to vehicles equipped with a drive motor such as a hybrid vehicle. Therefore, the first embodiment is applicable to the power supply systems of various vehicles such as one-wheeled vehicles, two-wheeled vehicles, and four-wheeled vehicles.

[0018] The power device 10 is not limited to the power supply system of the electric vehicle 24, but can be applied to various power supply systems that supply power from a plurality of power storage units 12 to a load 38 (described later) and the like. Therefore, the power device 10 can be applied to the power supply systems of various mobile bodies such as vehicles, aircraft, flying objects, and ships on which people can ride. The power device 10 can also be applied to the power supply systems of various general-purpose devices that do not have people on board, specifically, (1) various chargers, (2) various dischargers, (3) various working machines such as general-purpose working machines, lawnmowers, tillers, and blowers, (4) electric devices without electric motors such as floodlights and lighting equipment, and (5) various devices installed in houses and buildings.

[0019] The multiple power storage units 12 are power storage devices that are detachable from the power device 10 and can be charged and discharged. For example, a battery pack of a detachable lithium ion battery is suitable as the power storage unit 12. In the first embodiment, it is sufficient that at least one power storage unit 12 is detachable from the power device 10.

[0020] FIG. 1 illustrates, as an example, a case in which four power storage units 12 (hereinafter also referred to as first to fourth power storage units 12a to 12d) are arranged, four power transmission paths 14 (hereinafter also referred to as first to fourth power transmission paths 14a to 14d) are electrically connected to the four power storage units 12, and interrupters 16 (hereinafter also referred to as first to fourth interrupters 16a to 16d) and one-way rectifiers 18 (hereinafter also referred to as first to fourth unidirectional rectifiers 18a to 18d) are arranged in the four power transmission paths 14.

[0021] In the first embodiment, at least two power storage units 12, two power transmission paths 14, two interrupting units 16, and two one-way rectifying units 18 may be disposed in the power device 10. In this case, one of the power storage units 12 becomes the first power storage unit 12a, and one of the power transmission paths 14 electrically connected to the first power storage unit 12a becomes the first power transmission path 14a. Therefore, one of the interrupting units 16 and one of the one-way rectifying units 18 disposed in the first power transmission path 14a become the first interrupting unit 16a and the first one-way rectifying unit 18a. In addition, the other power storage unit 12 becomes the second power storage unit 12b, and the other power transmission path 14 electrically connected to the second power storage unit 12b becomes the second power transmission path 14b. Therefore, the other interruption unit 16 and the other unidirectional rectification unit 18 arranged in the second power transmission path 14b become the second interruption unit 16b and the second unidirectional rectification unit 18b.

[0022] In the first embodiment, the first to fourth power storage units 12a to 12d are numbered in descending order of voltage (hereinafter also referred to as battery voltage) or in descending order of power storage amount such as SOC (State Of Charge) before the first to fourth power storage units 12a to 12d are output (discharged). Therefore, the arrangement order (connection order) of the first to fourth power storage units 12a to 12d in the power device 10 may be random.

[0023] In this case, once the numbers are assigned, the order does not change even if the battery voltage or SOC of the first to fourth power storage units 12a to 12d changes due to subsequent discharging. However, when a power storage unit 12 that is out of charge is removed from the power device 10 and replaced with a fully charged power storage unit 12, the numbering process may be performed again. In addition, when some power storage units 12 have approximately the same battery voltage or SOC value, the power storage units 12 with the same value are numbered in an arbitrary order.

[0024] The multiple power transmission paths 14 electrically connect the output side of any one of the power storage units 12 to the connection unit 20. In this case, the multiple power transmission paths 14 have a positive electrode line 26 and a negative electrode line 28. The positive electrodes of the multiple power storage units 12 are electrically connected to the positive electrode line 26 of any one of the power transmission paths 14. The negative electrodes of the multiple power storage units 12 are electrically connected to the negative electrode line 28 of any one of the power transmission paths 14.

[0025] The connection unit 20 is a junction box that connects the multiple power transmission paths 14 in parallel. That is, the input side of the connection unit 20 is provided with multiple input side positive terminals 30 connected to any of the positive lines 26 of the multiple power transmission paths 14, and multiple input side negative terminals 32 connected to any of the negative lines 28 of the multiple power transmission paths 14. The output side of the connection unit 20 is provided with one output side positive terminal 34 and one output side negative terminal 36. Inside the connection unit 20, the multiple input side positive terminals 30 are connected in parallel to the output side positive terminal 34, and the multiple input side negative terminals 32 are connected in parallel to the output side negative terminal 36. As a result, the multiple power storage units 12 are connected in parallel to the connection unit 20 via the multiple power transmission paths 14.

[0026] A load 38, such as a motor and a power drive unit (PDU) of the electric vehicle 24, is electrically connected to the output side (output side positive terminal 34, output side negative terminal 36) of the connection unit 20. The load 38 is not limited to a motor and a PDU, but may be any device or equipment that uses the power of the multiple power storage units 12. Furthermore, on the output side of the connection unit 20, general electrical equipment 40, which is an auxiliary device of the electric vehicle 24, is connected in parallel to the load 38. Therefore, the multiple power storage units 12 are connected in parallel to the load 38 and the general electrical equipment 40 via the multiple power transmission paths 14 and the connection unit 20.

[0027] The PDU is an inverter that converts DC power supplied from the multiple power storage units 12 via the multiple power transmission paths 14 and the connection unit 20 into AC power. The motor receives the AC power converted by the PDU and drives the motor to run the electric vehicle 24. Although general electrical equipment 40 is illustrated in FIG. 1, the general electrical equipment 40 may be included in the load 38.

[0028] The interrupting portion 16 and the one-way rectifying portion 18 are arranged in series in the positive line 26 of the multiple power transmission paths 14. That is, the interrupting portion 16 and the one-way rectifying portion 18 are connected in series in the positive line 26.

[0029] The interrupter 16 is a switching means (switching element) such as a contactor or relay that switches the positive line 26 between the power storage unit 12 side and the connection unit 20 side to a connected state or a disconnected state based on a control signal from the ECU 22.

[0030] The unidirectional rectifier 18 is a rectifier such as a diode that passes a current so as to transmit power only in the direction from the power storage unit 12 to the connection unit 20. Thus, the unidirectional rectifier 18 prevents a current from flowing in the direction from the connection unit 20 to the power storage unit 12.

[0031] In other words, the power device 10 of the first embodiment supplies power from the multiple power storage units 12 to the load 38 and general electrical equipment 40 via the multiple power transmission paths 14 and the connection units 20 by discharging the multiple power storage units 12.

[0032] In the power device 10, the multiple power storage units 12, the load 38, and the general electrical equipment 40 can transmit and receive signals or information via a communication line 42 that constitutes a CAN (Controller Area Network) of the electric vehicle 24. The ECU 22 is an electronic control device mounted on the electric vehicle 24, and functions as a control unit that controls each part of the power device 10 by reading and executing a program stored in a non-volatile memory (not shown).

[0033] Specifically, the ECU 22 acquires various pieces of information related to the plurality of power storage units 12 from the plurality of power storage units 12 via the communication line 42. In addition, the ECU 22 acquires output requests of the load 38 and the general electrical components 40 from the load 38 and the general electrical components 40 via the communication line 42.

[0034] The ECU 22 supplies control signals to the multiple interrupters 16 based on the acquired information, and controls the multiple interrupters 16 to switch the multiple interrupters 16 between a connected state or a disconnected state. As a result, power according to an output request is supplied from the multiple power storage units 12 to the load 38 and general electrical equipment 40 via the multiple power transmission paths 14 and the connection unit 20. In other words, the ECU 22 controls the transmission of power from the multiple power storage units 12 to the load 38 and general electrical equipment 40 via the multiple power transmission paths 14 by controlling the multiple interrupters 16 to switch between a connected state or a disconnected state.

[0035] Fig. 2 is an internal configuration diagram of the multiple power storage units 12. The multiple power storage units 12 have the same configuration, and Fig. 2 illustrates only one power storage unit 12. Also, Fig. 2 illustrates each component of the power device 10 other than the power storage unit 12 in a simplified manner. As shown in Fig. 2, the multiple power storage units 12 are battery packs that accommodate a switch 44, a battery 46, a battery management system (BMU) 48, a resistor 50, a temperature sensor 52, and a communication unit 54.

[0036] The positive electrode of the battery 46 is electrically connected to the positive electrode line 26 of the power transmission path 14 via the switch 44 and the positive electrode terminal of the power storage unit 12. The negative electrode of the battery 46 is electrically connected to the negative electrode line 28 of the power transmission path 14 via a resistor 50 and the negative electrode terminal of the power storage unit 12. In addition, the communication unit 54 transmits and receives signals or information to and from the ECU 22 via the communication line 42.

[0037] The BMU 48 is started when the switch 44 is turned on under the control of the ECU 22 and power is supplied from a built-in battery (not shown) provided in the power device 10. The BMU 48 monitors the battery 46 and performs other functions.

[0038] Specifically, the BMU 48 electrically connects the battery 46 to the power transmission path 14 by turning on the switch 44 based on a control signal received by the communication unit 54 from the ECU 22 via the communication line 42. The BMU 48 also sequentially detects the voltage values ​​across the resistor 50, and sequentially calculates the current value of the current (discharge current in the first embodiment) flowing through the battery 46 based on the detected voltage value and the resistance value of the resistor 50. The BMU 48 also sequentially detects the value (voltage value) of the voltage (battery voltage) of the battery 46, and sequentially calculates the SOC of the battery 46 based on the detected voltage value and the calculated current value. Furthermore, the BMU 48 also sequentially acquires the temperature of the battery 46 (hereinafter referred to as battery temperature) detected by a temperature sensor 52 such as a thermistor.

[0039] The BMU 48 sequentially transmits various pieces of information, including the voltage value, the current value, the SOC, and the battery temperature, from the communication unit 54 to the ECU 22 via the communication line 42. Therefore, the ECU 22 sequentially acquires each piece of information described above, and can determine whether to switch the multiple interrupters 16 to a connected state or a disconnected state based on each piece of acquired information.

[0040] [2. Characteristic Functions of the First Embodiment] Next, characteristic functions of the power device 10 according to the first embodiment (hereinafter also referred to as characteristic functions of the first embodiment) will be described with reference to Figures 3 to 7B. The characteristic functions of the first embodiment are to prevent overcurrent from flowing even when multiple interrupters 16 are in a connected state by providing a one-way rectifier 18 in the power transmission path 14, and to prevent the occurrence of a time period during which power is not transmitted (output) to the load 38 and the general electrical equipment 40.

[0041] <2.1 Problems (comparative example)> 3 to 5B are conceptual diagrams illustrating problems that arise when a power device 60 of a comparative example is used. In the comparative example, components that are the same as those of the power device 10 (see FIGS. 1 and 2) according to the first embodiment are described with the same reference numerals. Also, in FIGS. 3 to 5B, for ease of explanation, the configuration of the power device 60 of the comparative example is illustrated in a simplified manner. Therefore, it should be noted that, for ease of explanation, general electrical components 40 and the like are not illustrated in FIGS. 3 to 5B.

[0042] The power device 60 of the comparative example differs from the power device 10 according to the first embodiment in that it does not include a one-way rectification unit 18 (see FIGS. 1 and 2), as shown in Fig. 3. Note that Fig. 3 illustrates a case in which the multiple interrupters 16 are in an interrupted state and the SOC of the multiple power storage units 12 is 100%. In other words, Fig. 3 illustrates a state before power is supplied from each power storage unit 12 to the load 38, and each power storage unit 12 is fully charged.

[0043] Here, as shown in Fig. 4A, when only interruption unit 16 (first interruption unit 16a) electrically connected to one power storage unit 12 (first power storage unit 12a) is switched to the connected state, a current flows from first power storage unit 12a to load 38 via first interruption unit 16a, and power supply from first power storage unit 12a to load 38 is started. As a result, first power storage unit 12a is discharged, and the SOC of first power storage unit 12a decreases from 100%. Note that in Figs. 4A to 5B, a line electrically connected to a path for supplying power to load 38 is shown by a thick line.

[0044] When first power storage unit 12a is discharged and SOC falls to 0%, first power storage unit 12a runs out of power. Then, second interrupter 16b electrically connected to second power storage unit 12b is switched to a connected state as shown in Fig. 4B. This causes a current to flow from second power storage unit 12b to load 38 via second interrupter 16b, and power supply from second power storage unit 12b to load 38 begins.

[0045] In this case, because first interrupter 16a is in a connected state, a circulating current, which is an overcurrent, occurs between second fully charged power storage unit 12b and first power storage unit 12a in an out-of-charge state due to a difference in battery voltage (hereinafter referred to as a battery voltage difference) or a difference in SOC (hereinafter referred to as a SOC difference (electrical storage amount difference)). This circulating current flows from second power storage unit 12b through second interrupter 16b and first interrupter 16a to first power storage unit 12a.

[0046] In order to avoid the occurrence of such an overcurrent (circulating current), it is conceivable to switch the first interrupter 16a to a cut-off state when the first power storage unit 12a is discharged and the SOC falls to 0%, as shown in Fig. 5A, and then switch the second power storage unit 12b to a connected state, as shown in Fig. 5B. However, with this method, during the time period from when the first power storage unit 12a is switched to the cut-off state to when the second interrupter 16b is switched to the connected state, no power is supplied from the multiple power storage units 12 to the load 38 (power supply is interrupted). This makes it difficult to drive the electric vehicle 24 appropriately.

[0047] <2.2 Overview of Characteristic Functions of the First Embodiment> Fig. 6A is a conceptual diagram illustrating a characteristic function of the first embodiment for solving the above problems. Fig. 6A illustrates a simplified configuration of the power device 10 in Fig. 1. Therefore, for the sake of convenience, Fig. 6A also omits the illustration of the general electrical equipment 40 and the like.

[0048] A characteristic function of the first embodiment is that the first to fourth interrupting units 16a to 16d and the first to fourth unidirectional rectifying units 18a to 18d are connected in series in the first to fourth power transmission paths 14a to 14d. Note that Fig. 6A shows a state before power is supplied to the load 38, and the first to fourth power storage units 12a to 12d are in a fully charged state (SOC: 100%).

[0049] 6B, when only first interrupter 16a is switched to the connected state, power can be supplied from first power storage unit 12a to load 38 via first interrupter 16a and first one-way rectifier 18a. As a result, output (discharge) of power from first power storage unit 12a begins, and the SOC of first power storage unit 12a decreases from 100%.

[0050] Next, as shown in FIG. 7A, when the first interrupter 16a is in the connected state, the second storage unit 12b is switched to the connected state. This allows power to be supplied from the second storage unit 12b to the load 38 via the second interrupter 16b and the second one-way rectifier 18b. In this case, since the first one-way rectifier 18a is provided, even if there is a difference in SOC between the first storage unit 12a and the second storage unit 12b, it is possible to prevent a circulating current (overcurrent) from flowing from the second storage unit 12b to the first storage unit 12a. In addition, since the second interrupter 16b is switched to the connected state when the first interrupter 16a is in the connected state, it is possible to avoid a time period during which power supply to the load 38 is interrupted. The second storage unit 12b may be switched to the connected state at a timing when the SOC of the first storage unit 12a falls to a predetermined threshold (lower discharge threshold).

[0051] Next, after it is confirmed that power supply from the second power storage unit 12b to the load 38 has started, the first interrupter 16a is switched to the interrupted state as shown in Fig. 7B. In this manner, in the first embodiment, the power supply from the first power storage unit 12a to the load 38 can be switched to the power supply from the second power storage unit 12b to the load 38 reliably and efficiently.

[0052] In the above description, the multiple interrupting units 16 are switched between the connected state and the disconnected state based on the magnitude or SOC difference of the multiple power storage units 12. In the characteristic function of the first embodiment, it is also possible to switch the multiple interrupting units 16 between the connected state and the disconnected state based on the battery voltage difference of the multiple power storage units 12 corresponding to the SOC difference.

[0053] <2.3 Specific method of power supply using characteristic functions of the first embodiment> Next, a specific method for supplying power to the load 38 using the characteristic functions of the first embodiment will be described with reference to FIGS.

[0054] FIG. 8 is a flowchart illustrating a case in which the first to fourth power storage units 12a to 12d (see FIGS. 1, 2, and 6A to 7B) are sequentially connected to the connection unit 20 by switching the first to fourth interruption units 16a to 16d to a connected state or a disconnected state depending on the battery voltage difference or SOC difference between the first to fourth power storage units 12a to 12d.

[0055] 8, four battery packs 70 (hereinafter also referred to as first to fourth battery packs 70a to 70d) that can become the power storage unit 12 are mounted on the power device 10. As a result, the first to fourth battery packs 70a to 70d are capable of transmitting and receiving signals or information to and from the ECU 22 via the communication line 42.

[0056] 9A to 10B typically illustrate that the first to fourth battery packs 70a to 70d are capable of communicating with the ECU 22. In addition, in Fig. 9A to 10B, the magnitude of the battery voltage or SOC of each of the battery packs 70a to 70d is illustrated by a bar graph with multiple segments.

[0057] In this case, the first to fourth battery packs 70a to 70d detect the battery voltages and SOCs, and transmit the detection results to the ECU 22 via the communication line 42. The ECU 22 acquires the detection results of the battery voltages and SOCs of the first to fourth battery packs 70a to 70d via the communication line 42.

[0058] In step S2 in FIG. 8, ECU 22 (see FIGS. 1, 2 and 9A) numbers the current first to fourth battery packs 70a to 70d in order from the battery pack with the largest battery voltage or SOC (capacity), and assigns them as first to fourth power storage units 12a to 12d.

[0059] 9A, the battery packs having the largest battery voltages or SOCs are the third battery pack 70c, the first battery pack 70a, the second battery pack 70b, and the fourth battery pack 70d. Therefore, in step S2, the third battery pack 70c is assigned to the first power storage unit 12a, the first battery pack 70a is assigned to the second power storage unit 12b, the second battery pack 70b is assigned to the third power storage unit 12c, and the fourth battery pack 70d is assigned to the fourth power storage unit 12d.

[0060] Therefore, in the first embodiment, it should be noted that the order in which the first to fourth battery packs 70a to 70d are connected to the power device 10 may differ from the order in which the first to fourth power storage units 12a to 12d are numbered. Also, when there are multiple battery packs 70 with the same battery voltage or SOC, the battery packs 70 with the same value may be numbered in any order.

[0061] Then, the ECU 22 notifies the first to fourth battery packs 70a to 70d of the result of the numbering process via the communication line 42. Thus, the first to fourth battery packs 70a to 70d can recognize to which power storage unit 12 they are assigned by receiving the notification from the ECU 22. Note that when the numbering process is performed in step S2, the assigned numbers do not change even if the battery voltages or SOCs of the first to fourth power storage units 12a to 12d fluctuate in the subsequent process.

[0062] ECU 22 acquires an output request from load 38 and general electrical equipment 40 via communication line 42. ECU 22 controls first to fourth interrupters 16a to 16d so as to output (discharge) electric power according to the output request from first to fourth power storage units 12a to 12d. Then, in step S3, ECU 22 determines whether the battery voltage difference or SOC difference between first power storage unit 12a and fourth power storage unit 12d is within a first predetermined value (third predetermined value).

[0063] If the battery voltage difference or SOC difference between the first power storage unit 12a and the fourth power storage unit 12d exceeds a first predetermined value (step S3: NO), the process proceeds to step S4, and the ECU 22 determines whether the battery voltage difference or SOC difference between the first power storage unit 12a and the second power storage unit 12b is within a second predetermined value (third predetermined value).

[0064] When the battery voltage difference or SOC difference between first power storage unit 12a and second power storage unit 12b exceeds the second predetermined value (step S4: NO), ECU 22 determines that when first power storage unit 12a and second power storage unit 12b are connected, a circulating current (overcurrent) corresponding to the battery voltage difference or SOC difference (capacity difference) may flow from first power storage unit 12a to second power storage unit 12b. In the next step S5, ECU 22 determines to supply (output) power from first power storage unit 12a to load 38 by switching only first interrupter 16a to the connected state.

[0065] As a result, the ECU 22 supplies a control signal to the first interrupter 16a to switch the first interrupter 16a from a disconnected state to a connected state. As a result, power is supplied from the first power storage unit 12a to the load 38 and the general electrical equipment 40 via the first interrupter 16a, the first one-way rectifier 18a, and the connection unit 20.

[0066] In the next step S6, ECU 22 determines whether the battery voltage difference or the SOC difference between first power storage unit 12a and third power storage unit 12c is within a third predetermined value (second predetermined value, third predetermined value).

[0067] When the battery voltage difference or SOC difference between the first and third power storage units 12a and 12c exceeds a third predetermined value (step S6: NO), the ECU 22 determines that connecting the first and third power storage units 12a and 12c may cause a circulating current (overcurrent) corresponding to the battery voltage difference or SOC difference (capacity difference) to flow from the first and third power storage units 12a and 12c, and decides to maintain the current connection state.

[0068] Thereafter, ECU 22 returns to step S3 and repeatedly executes the processes in and after step S3. Note that first to fourth power storage units 12a to 12d successively detect the battery voltages and SOCs, and transmit the detection results to ECU 22 via communication line 42. Therefore, in the processes in and after step S3, ECU 22 executes the processes in and after step S3 using the most recent battery voltages and SOCs of first to fourth power storage units 12a to 12d (step S3 → step S4 → step S5 → step S6).

[0069] As first power storage unit 12a continues to output power to load 38 and general electrical equipment 40, the battery voltage or SOC of first power storage unit 12a gradually decreases over time from the fully charged state. Then, in step S4, when the battery voltage difference or SOC difference between first power storage unit 12a and second power storage unit 12b is within the second predetermined value (step S4: YES), ECU 22 determines that even if first power storage unit 12a and second power storage unit 12b are connected to each other, no circulating current (overcurrent) will flow from first power storage unit 12a to second power storage unit 12b.

[0070] Next, the ECU 22 proceeds to step S7, and decides to supply (output) power from the first power storage unit 12a and the second power storage unit 12b to the load 38 by switching the second power storage unit 16b to a connected state while maintaining the first power storage unit 16a in a connected state.

[0071] As a result, the ECU 22 supplies a control signal to the second interrupter 16b to switch the second interrupter 16b from a disconnected state to a connected state. As a result, power supply is started from the second power storage unit 12b to the load 38 and the general electrical components 40 via the second interrupter 16b, the second one-way rectifier 18b, and the connection unit 20. Fig. 9B illustrates that in step S7, the first interrupter 16a and the second interrupter 16b are brought into a connected state, so that power is supplied from the first power storage unit 12a and the second power storage unit 12b to the load 38.

[0072] After step S7, the process proceeds to step S6, where ECU 22 again determines whether the battery voltage difference or SOC difference between first power storage unit 12a and third power storage unit 12c is within the third predetermined value. In this case, if the battery voltage difference or SOC difference between first power storage unit 12a and third power storage unit 12c exceeds the third predetermined value (step S6: NO), ECU 22 determines that if first to third power storage units 12a to 12c are connected, a circulating current (overcurrent) corresponding to the battery voltage difference or SOC difference (capacity difference) may flow from first power storage unit 12a and second power storage unit 12b to third power storage unit 12c, and determines to maintain the current connection state.

[0073] Thereafter, the ECU 22 returns to step S3, and repeats the processes from step S3 onwards (step S3 -> step S4 -> step S7 -> step S6).

[0074] The battery voltage or SOC of first power storage unit 12a and second power storage unit 12b gradually decreases over time as power is continuously output from first power storage unit 12a and second power storage unit 12b to load 38 and general electrical equipment 40. Then, in step S6, when the battery voltage difference or SOC difference between first power storage unit 12a and third power storage unit 12c is within the third predetermined value (step S6: YES), ECU 22 determines that even if first to third power storage units 12a to 12c are connected, a circulating current (overcurrent) will not flow from first power storage unit 12a and second power storage unit 12b to third power storage unit 12c.

[0075] Next, the ECU 22 proceeds to step S8, and decides to supply (output) power from the first to third power storage units 12a to 12c to the load 38 by switching the third power storage unit 16c to a connected state while maintaining the first and second power storage units 16a and 16b in a connected state.

[0076] As a result, the ECU 22 supplies a control signal to the third interrupter 16c to switch the third interrupter 16c from a disconnected state to a connected state. As a result, power supply is started from the third power storage unit 12c to the load 38 and the general electrical components 40 via the third interrupter 16c, the third one-way rectifier 18c, and the connection unit 20. Fig. 10A illustrates that the first to third interrupter units 16a to 16c are switched to the connected state in step S8, so that power is supplied from the first to third power storage units 12a to 12c to the load 38.

[0077] After step S8, the ECU 22 returns to step S3, and repeats the processes from step S3 onwards (step S3 -> step S4 -> step S7 -> step S6 -> step S8).

[0078] The battery voltages or SOCs of the first to third power storage units 12a to 12c gradually decrease over time as power is continuously output from the first to third power storage units 12a to 12c to the load 38 and the general electrical components 40. Then, in step S3, when the battery voltage difference or SOC difference between the first power storage unit 12a and the fourth power storage unit 12d is within the first predetermined value (step S3: YES), ECU 22 determines that even if the first to fourth power storage units 12a to 12d are connected, a circulating current (overcurrent) will not flow from the first to third power storage units 12a to 12c to the fourth power storage unit 12d.

[0079] Next, the ECU 22 proceeds to step S9, and decides to supply (output) power from the first to fourth power storage units 12a to 12d to the load 38 by switching the fourth power storage unit 16d to a connected state while maintaining the first to third power storage units 16a to 16c in a connected state.

[0080] As a result, the ECU 22 supplies a control signal to the fourth interrupter 16d to switch the fourth interrupter 16d from a disconnected state to a connected state. As a result, power supply is started from the fourth power storage unit 12d to the load 38 and the general electrical components 40 via the fourth interrupter 16d, the fourth one-way rectifier 18d, and the connection unit 20. Fig. 10B illustrates that the first to fourth interrupter units 16a to 16d are switched to the connected state in step S9, so that power is supplied from the first to fourth power storage units 12a to 12d to the load 38.

[0081] In the next step S10, ECU 22 determines whether the battery voltage or SOC of first to fourth power storage units 12a to 12d has decreased to a discharge lower limit threshold. If the battery voltage or SOC has decreased to a discharge lower limit threshold (step S10: YES), ECU 22 determines that first to fourth power storage units 12a to 12d have run out of power, and determines to stop power supply to load 38 and general electrical equipment 40.

[0082] As a result, the ECU 22 stops supplying the control signals to the first to fourth interrupters 16a to 16d, and switches the first to fourth interrupters 16a to 16d from a connected state to a disconnected state. As a result, the power supply from the first to fourth power storage units 12a to 12d to the load 38 and the general electrical equipment 40 ends.

[0083] In the flowchart of FIG. 8, the first to third predetermined values ​​may be the same value or may be different values ​​from each other.

[0084] Fig. 11 is a flowchart obtained by partially modifying Fig. 8. That is, Fig. 8 describes a case in which first to fourth power storage units 12a to 12d are connected in sequence to output electric power to load 38 and general electrical equipment 40. In Fig. 11, electric power is supplied from first power storage unit 12a and second power storage unit 12b to load 38 and general electrical equipment 40, and then, when first power storage unit 12a and second power storage unit 12b drop to the lower discharge threshold, electric power supply is switched to from third power storage unit 12c and fourth power storage unit 12d to load 38 and general electrical equipment 40.

[0085] In this case, after processing steps S1 and S2 in FIG. 8, the process proceeds to step S11 in FIG. 11, where ECU 22 determines whether the battery voltage difference or SOC difference between first power storage unit 12a and second power storage unit 12b is within a fourth predetermined value (third predetermined value).

[0086] When the battery voltage difference or SOC difference between first power storage unit 12a and second power storage unit 12b exceeds the fourth predetermined value (step S11: NO), ECU 22 determines that there is a possibility that a circulating current (overcurrent) corresponding to the battery voltage difference or SOC difference (capacity difference) will flow if the respective power storage units 12 are connected. Then, in the next step S12, ECU 22 prohibits parallel connection of the respective power storage units 12 and determines to supply (output) electric power from first power storage unit 12a to load 38 by, for example, switching only first interrupter 16a to the connected state.

[0087] As a result, the ECU 22 supplies a control signal to the first interrupter 16a to switch the first interrupter 16a from a disconnected state to a connected state. As a result, power is supplied from the first power storage unit 12a to the load 38 and the general electrical equipment 40 via the first interrupter 16a, the first one-way rectifier 18a, and the connection unit 20.

[0088] Thereafter, the ECU 22 returns to step S1 and repeats the processes of steps S1, S2 and S11.

[0089] As first power storage unit 12a continues to output power to load 38 and general electrical equipment 40, the battery voltage or SOC of first power storage unit 12a gradually decreases over time from the fully charged state. Then, in step S11, when the battery voltage difference or SOC difference between first power storage unit 12a and second power storage unit 12b is within the fourth predetermined value (step S11: YES), ECU 22 determines that even if first power storage unit 12a and second power storage unit 12b are connected to each other, a circulating current (overcurrent) will not flow from first power storage unit 12a to second power storage unit 12b.

[0090] Then, the process proceeds to step S13, where ECU 22 determines whether the battery voltage difference or the SOC difference between third power storage unit 12c and fourth power storage unit 12d is within a fifth predetermined value (first predetermined value, third predetermined value).

[0091] If the battery voltage difference or SOC difference between the third power storage unit 12c and the fourth power storage unit 12d is within the fifth predetermined value (step S13: YES), the ECU 22 determines that even if the third power storage unit 12c and the fourth power storage unit 12d are connected, no circulating current (overcurrent) will flow from the third power storage unit 12c to the fourth power storage unit 12d.

[0092] Next, the ECU 22 proceeds to step S14, and in response to the affirmative determination result in step S11, determines to supply (output) electric power from the first power storage unit 12a and the second power storage unit 12b to the load 38 by switching the second interruption unit 16b to a connection state while maintaining the connection state of the first interruption unit 16a. As a result, the ECU 22 supplies a control signal to the second interruption unit 16b, and switches the second interruption unit 16b from a disconnection state to a connection state. As a result, electric power supply from the second power storage unit 12b to the load 38 and the general electrical components 40 via the second interruption unit 16b, the second one-way rectification unit 18b, and the connection unit 20 is started.

[0093] In the next step S15, ECU 22 determines whether the battery voltage or SOC of first power storage unit 12a and second power storage unit 12b has decreased to a lower discharge threshold value. If the battery voltage or SOC has decreased to a lower discharge threshold value (step S15: YES), ECU 22 proceeds to step S16 and determines to switch power supply from third power storage unit 12c and fourth power storage unit 12d to load 38 and general electrical equipment 40 because first power storage unit 12a and second power storage unit 12b are in a power-starved state.

[0094] In this case, the ECU 22 first supplies a control signal to the third interruption unit 16c and the fourth interruption unit 16d while maintaining the connection state of the first interruption unit 16a and the second interruption unit 16b, and switches the third interruption unit 16c and the fourth interruption unit 16d from the disconnection state to the connection state. As a result, power supply from the third power storage unit 12c and the fourth power storage unit 12d to the load 38 and the general electrical equipment 40 is started via the third interruption unit 16c and the fourth interruption unit 16d, the third one-way rectification unit 18c and the fourth one-way rectification unit 18d, and the connection unit 20. Next, the ECU 22 stops the control signal to the first interruption unit 16a and the second interruption unit 16b, and switches the connection state from the disconnection state to the disconnection state.

[0095] In the next step S17, the ECU 22 determines whether the battery voltage or SOC of the third power storage unit 12c and the fourth power storage unit 12d has fallen to the discharge lower limit threshold. If the battery voltage or SOC has fallen to the discharge lower limit threshold (step S17: YES), the ECU 22 determines that the third power storage unit 12c and the fourth power storage unit 12d are in a power-starved state, and determines to stop the power supply to the load 38 and the general electrical equipment 40. As a result, the ECU 22 stops the supply of control signals to the third interrupter 16c and the fourth interrupter 16d, and switches the third interrupter 16c and the fourth interrupter 16d from a connected state to a disconnected state. As a result, the power supply from the third power storage unit 12c and the fourth power storage unit 12d to the load 38 and the general electrical equipment 40 ends.

[0096] On the other hand, in step S13, when the battery voltage difference or the SOC difference between the third power storage unit 12c and the fourth power storage unit 12d exceeds the fifth predetermined value (step S13: NO), the ECU 22 determines that there is a possibility that a circulating current (overcurrent) will flow from the third power storage unit 12c to the fourth power storage unit 12d when the third power storage unit 12c and the fourth power storage unit 12d are connected. Then, the ECU 22 proceeds to step S18, and supplies a control signal to the second interrupter 16b to switch the second interrupter 16b from the disconnected state to the connected state in the same manner as in step S14, thereby executing power supply from the first power storage unit 12a and the second power storage unit 12b to the load 38 and the general electrical equipment 40 via the first interrupter 16a and the second interrupter 16b, the first unidirectional rectifier 18a and the second unidirectional rectifier 18b, and the connection unit 20.

[0097] In the next step S19, ECU 22 determines whether the battery voltage difference or the SOC difference between first power storage unit 12a and third power storage unit 12c is within a sixth predetermined value (second predetermined value, third predetermined value).

[0098] The battery voltage or SOC of first power storage unit 12a and second power storage unit 12b gradually decreases over time as power is continuously output from first power storage unit 12a and second power storage unit 12b to load 38 and general electrical component 40. Therefore, in step S19, when the battery voltage difference or SOC difference between first power storage unit 12a and third power storage unit 12c is within the sixth predetermined value (step S19: YES), ECU 22 determines that even if first to third power storage units 12a to 12c are connected, a circulating current (overcurrent) will not flow from first power storage unit 12a and second power storage unit 12b to third power storage unit 12c.

[0099] Then, the ECU 22 proceeds to step S20 and determines to supply (output) electric power from the first to third power storage units 12a to 12c to the load 38. In this case, the ECU 22 supplies a control signal to the third interruption unit 16c while maintaining the connection state of the first interruption unit 16a and the second interruption unit 16b, thereby switching the third interruption unit 16c from a disconnected state to a connected state. As a result, electric power supply from the third power storage unit 12c to the load 38 and the general electrical components 40 via the third interruption unit 16c, the third one-way rectification unit 18c, and the connection unit 20 is started.

[0100] The battery voltages or SOCs of the first to third power storage units 12a to 12c gradually decrease over time as power is continuously output from the first to third power storage units 12a to 12c to the load 38 and the general electrical components 40. Therefore, in step S21, when the battery voltage difference or SOC difference between the third power storage unit 12c and the fourth power storage unit 12d is within the seventh predetermined value (first predetermined value) (step S21: YES), the ECU 22 determines that even if the third power storage unit 12c and the fourth power storage unit 12d are connected, a circulating current (overcurrent) will not flow from the third power storage unit 12c to the fourth power storage unit 12d.

[0101] In the next step S22, the ECU 22 stops the supply of the control signal to the third interruption unit 16c while maintaining the connection state of the first interruption unit 16a and the second interruption unit 16b, and switches the third interruption unit 16c from the connection state to the interruption state. As a result, power supply is switched from the first power storage unit 12a and the second power storage unit 12b to the load 38 and the general electrical equipment 40. Then, the ECU 22 executes the process of step S15.

[0102] In other words, the processing of steps S18 to S22 is executed to connect the first to third power storage units 12a to 12c in parallel to the load 38 and general electrical equipment 40 and discharge the third power storage unit 12c in order to reduce the battery voltage difference or SOC difference between the third power storage unit 12c and the fourth power storage unit 12d and make the third power storage unit 12c and the fourth power storage unit 12d connectable.

[0103] [3. Description of the Second Embodiment] A power device 80 according to the second embodiment will be described with reference to Figures 12 to 15B. In the power device 80 according to the second embodiment, the same components as those in the power device 10 according to the first embodiment (see Figures 1, 2, and 6A to 7B) are given the same reference symbols and detailed descriptions thereof will be omitted.

[0104] The power device 80 according to the second embodiment differs from the power device 10 according to the first embodiment in that there is only one one-way rectification section 82 and a total of eight interruption sections 84 are provided. It should also be noted that in the power device 80 according to the second embodiment, the meanings of "first" and "second" attached to the interruption sections 84 and the like are different from those in the power device 10 according to the first embodiment.

[0105] Specifically, in the power device 80 according to the second embodiment, the multiple power storage units 12 are also connected in parallel to the connection unit 20 via multiple power transmission paths 86. However, in the power device 80 according to the second embodiment, the multiple power transmission paths 86 are composed of a first power transmission path 86a and a second power transmission path 86b that are electrically connected in parallel between the power storage units 12 and the connection unit 20.

[0106] A first power transmission path 86a of the multiple power transmission paths 86 corresponds to the multiple power transmission paths 14 of the power device 10 according to the first embodiment. Therefore, the multiple first power transmission paths 86a have a positive electrode line 26 and a negative electrode line 28. An interrupted portion 84 (hereinafter also referred to as a first interrupted portion 84a) is arranged in the multiple positive electrode lines 26. The multiple first interrupted portions 84a correspond to the multiple interrupted portions 16 of the power device 10 according to the first embodiment.

[0107] In the multiple power transmission paths 86, one end of the second power transmission path 86b is connected to a location on the positive electrode line 26 of the first power transmission path 86a between the power storage unit 12 and the first interrupter 84a. The other ends of the multiple second power transmission paths 86b are connected to each other and to an input side terminal 88 of the connection unit 20. The input side terminal 88 is electrically connected to the multiple input side positive electrode terminals 30 of the connection unit 20. As a result, in the multiple power transmission paths 86, the second power transmission path 86b is electrically connected in parallel to the first power transmission path 86a.

[0108] An interrupter 84 (hereinafter also referred to as a second interrupter 84b) is disposed between one end of the second power transmission paths 86b and a connection point of the other end of the second power transmission paths 86b. The second interrupters 84b are switching means that are switched between a connected state and a disconnected state by a control signal from the ECU 22, similar to the first interrupters 84a.

[0109] One unidirectional rectifier 82 is disposed between the connection points of the other ends of the multiple second power transmission paths 86b and the input terminal 88 of the connection unit 20. The one unidirectional rectifier 82 corresponds to the multiple unidirectional rectifiers 18 of the power device 10 according to the first embodiment. Therefore, one unidirectional rectifier 82 and multiple second interrupters 84b are disposed in the multiple second power transmission paths 86b. Furthermore, when viewed for each second power transmission path 86b, the unidirectional rectifier 82 and the second interrupters 84b are connected (disposed) in series.

[0110] Thus, in the power device 80 according to the second embodiment, the terms "first" and "second" affixed to the first and second interruption parts 84a and 84b constituting the interruption part 84 and the first and second power transmission paths 86a and 86b constituting the multiple power transmission paths 86 are used to define the connection relationship with the multiple power storage parts 12. Note that this is not stipulated by the magnitude of the battery voltage or SOC (power storage amount) as in the power device 10 according to the first embodiment.

[0111] Next, the operation of the power device 80 when switching power supply from one power storage unit 12 to the load 38 to power supply from the other power storage unit 12 to the load 38 will be described with reference to Figs. 13A to 15B. Figs. 13A to 15B are conceptual diagrams illustrating a simplified configuration of the power device 80 in Fig. 12. Therefore, for ease of explanation, general electrical components 40 and the like are omitted from Figs. 13A to 15B. Note that Fig. 13A illustrates a case where the multiple first interrupting units 84a and the multiple second interrupting units 84b are in an interrupted state, that is, a state before power is supplied to the load 38, and the multiple power storage units 12 are in a fully charged state (SOC: 100%).

[0112] Here, when a first power transmission path 86a connected to one power storage unit 12, a first interruption unit 84a arranged on the first power transmission path 86a, a second power transmission path 86b connected in parallel to the first power transmission path 86a, and a second interruption unit 84b arranged on the second power transmission path 86b are considered as one set, the power device 80 has a plurality of sets. Fig. 13A to Fig. 15B show a case where a state in which power is transmitted (output) to the load 38 via one set of first power transmission path 86a connected to one power storage unit 12 is switched to a state in which power is transmitted (output) to the load 38 via the other set of first power transmission path 86a connected to the other power storage unit 12.

[0113] In this case, first, in response to a control signal supplied from the ECU 22 (see FIG. 12), only the first interrupter 84a of one pair (one pair) is switched to a connected state as shown in FIG. 13B. This allows power to be supplied from the power storage unit 12 to the load 38 via the first interrupter 84a and the first power transmission path 86a in the one pair. This starts discharging the power storage unit 12 (output of power), and the SOC of the power storage unit 12 drops from 100%.

[0114] 14A , when the first interrupter 84a of one set is in the connected state, the ECU 22 supplies a control signal to the second interrupter 84b of one set to switch the second interrupter 84b from the disconnected state to the connected state. As a result, in the one set, a path is formed through which power is supplied from the power storage unit 12 to the load 38 via the first interrupter 84a and the first power transmission path 86a, and a path is formed through which power is supplied from the power storage unit 12 to the load 38 via the second interrupter 84b, the one-way rectifier 82, and the second power transmission path 86b.

[0115] 14B, the supply of the control signal from the ECU 22 to the first interrupter 84a of one of the pairs is stopped, and the first interrupter 84a is switched from the connected state to the disconnected state. As a result, in the one pair, power is supplied from the power storage unit 12 to the load 38 via the second interrupter 84b, the one-way rectifier 82, and the second power transmission path 86b.

[0116] Thereafter, when the battery voltage or SOC of the power storage unit 12 in one pair falls to the discharge lower limit threshold, the ECU 22 starts supplying a control signal to the first interrupter 84a in the other pair. Blocking From the state connection The state is switched to the ON state, and power starts to be supplied from the other power storage unit 12 to the load 38 via the other pair of first interlocking unit 84a and first power transmission path 86a.

[0117] In this case, since the first interrupter 84a of one set is in an interrupted state and the one-way rectifier 82 is provided, it is possible to prevent an overcurrent from flowing from the other fully charged power storage unit 12 to the one power storage unit 12 that has run out of power. It is also possible to avoid the occurrence of a state in which power supply to the load 38 is interrupted.

[0118] Next, the ECU 22 stops supplying the control signal to the second interrupter 84b of one pair. As a result, in one pair, the second interrupter 84b is switched from the connected state to the disconnected state as shown in Fig. 15B. In the other pair, power is continuously supplied from the other power storage unit 12 to the load 38 via the first interrupter 84a and the first power transmission path 86a.

[0119] Incidentally, the power device 80 according to the second embodiment is also capable of processing the supply of power to the load 38 shown in Figs. 8 to 11, similarly to the power device 10 according to the first embodiment.

[0120] [4. Effects of this embodiment] As described above, the first embodiment relates to a power device 10 having a plurality of power storage units 12, a plurality of power transmission paths 14 connected to the plurality of power storage units 12, and a connection unit 20 that connects the plurality of power storage units 12 in parallel via the plurality of power transmission paths 14. The power device 10 has one-way rectification units 18 arranged in the plurality of power transmission paths 14, and an interruption unit 16 that is arranged in series with the one-way rectification units 18 in the plurality of power transmission paths 14 and interrupts the power storage units 12 and the connection unit 20.

[0121] The first embodiment also relates to a control method for a power device 10 in which a plurality of power storage units 12 are connected in parallel to a connection unit 20 via a plurality of power transmission paths 14. The control method includes the steps of: switching an interrupter 16 arranged in one of the plurality of power transmission paths 14 to a connected state to transmit power via the interrupter 16 and one-way rectifier 18 arranged in series in one of the power transmission paths 14 (steps S14, S18); switching an interrupter 16 arranged in the other power transmission path 14 to a connected state to transmit power via the interrupter 16 and one-way rectifier 18 arranged in series in the other power transmission path 14 (steps S16, S20); and switching the interrupter 16 arranged in one of the power transmission paths 14 to a disconnected state (step S16).

[0122] In this way, since the one-way rectifier 18 is provided in the power transmission path 14, even if the interrupters 16 of the multiple power transmission paths 14 are connected, it is possible to prevent a circulating current (overcurrent) from flowing from a fully charged storage unit 12 to a storage unit 12 in an out-of-battery state. Furthermore, when the interrupters 16 of the multiple power transmission paths 14 are connected, power is output from the fully charged storage unit 12 via the connection unit 20, so it is possible to avoid the occurrence of a time period during which power is not transmitted (output) (a time period during which power supply to the load 38 is interrupted). Furthermore, since the configuration is simple, in which the interrupters 16 and the one-way rectifier 18 are arranged in series in the power transmission path 14, it is inexpensive and easy to control.

[0123] To explain in more detail, in the first embodiment, since the multiple interrupting units 16 can be switched between a connected state and a disconnected state individually, it is possible to individually permit or prohibit the output (discharge) of power from all the power storage units 12. Therefore, in the first embodiment, even if the power device 10 is equipped with a power storage unit 12 in a power-starved state, it is possible to adjust the number of power storage units 12 connected to the load 38 by switching the interrupting unit 16 connected to the power storage unit 12 to a disconnected state. In other words, in the first embodiment, it is possible to connect the power storage units 12 to the load 38 in any connection pattern regardless of the number of power storage units 12. This makes it possible to use up all the power storage units 12 to the end while controlling the output of power from the multiple power storage units 12 to the load 38.

[0124] Here, the power device 10 according to the first embodiment further has an ECU 22 (control unit) that controls the interrupter 16 to switch between a connected state in which the power storage unit 12 and the connection unit 20 are connected, or a disconnected state in which the power storage unit 12 and the connection unit 20 are disconnected.

[0125] In this case, one of the multiple power transmission paths 14 becomes the first power transmission path 14a, the one-way rectifier 18 arranged in the first power transmission path 14a becomes the first one-way rectifier 18a, and the interrupter 16 arranged in the first power transmission path 14a becomes the first interrupter 16a. The other of the multiple power transmission paths 14 becomes the second power transmission path 14b, the one-way rectifier 18 arranged in the second power transmission path 14b becomes the second unidirectional rectifier 18b, and the interrupter 16 arranged in the second power transmission path 14b becomes the second interrupter 16b.

[0126] When transitioning from a state in which power is transmitted only through the first power transmission path 14a due to the first interruption unit 16a being in a connected state and the second interruption unit 16b being in a disconnected state to a state in which power is transmitted only through the second power transmission path 14b, the ECU 22 first connects the second interruption unit 16b to a connected state and then connects the first interruption unit 16a to a disconnected state.

[0127] In this way, since the one-way rectifier 18 (the first one-way rectifier 18a, the second one-way rectifier 18b) is arranged on both the first power transmission path 14a and the second power transmission path 14b, it is possible to prevent a circulating current (overcurrent) from flowing from the second power storage unit 12b to the first power storage unit 12a due to a battery voltage difference. In addition, since the first interrupter 16a is switched to the interrupted state after both the first interrupter 16a and the second interrupter 16b are in the connected state, it is possible to prevent interruption of the power supply to the load 38 at the time of switching.

[0128] Moreover, the power device 10 according to the first embodiment further includes an ECU 22 (controller) that controls the transmission of power through the multiple power transmission paths 14 by controlling the interrupter 16 to switch between a connection state in which the power storage unit 12 and the connection unit 20 are connected and a disconnection state in which the power storage unit 12 and the connection unit 20 are disconnected. The ECU 22 numbers the multiple power storage units 12 in order from the power storage unit 12 having the largest battery voltage or SOC (power storage amount). Thus, when transmitting power through two of the multiple power transmission paths 14, the ECU 22 controls the multiple interrupters 16 so that power is transmitted through the first power transmission path 14a connected to the first power storage unit 12a and the second power transmission path 14b connected to the second power storage unit 12b.

[0129] As a result, power can be output in order from first power storage unit 12a and second power storage unit 12b having larger battery voltage or SOC to load 38. Therefore, power can be extracted from each of two power storage units 12 connected in parallel.

[0130] In addition, when the battery voltage difference or SOC difference (difference in power storage amount) between the third power storage unit 12c and the fourth power storage unit 12d exceeds a fifth predetermined value or a seventh predetermined value (first predetermined value), the ECU 22 controls the multiple interrupters 16 to transmit power via the first to third power transmission paths 14a to 14c connected to the first to third power storage units 12a to 12c before switching from a state in which power is transmitted via the first power transmission path 14a connected to the first power storage unit 12a and the second power transmission path 14b connected to the second power storage unit 12b to a state in which power is transmitted via the third power transmission path 14c connected to the third power storage unit 12c and the fourth power transmission path 14d connected to the fourth power storage unit 12d.

[0131] As a result, the battery voltage or SOC of third power storage unit 12c decreases over time due to the output of power from third power storage unit 12c. As a result, the battery voltage difference or SOC difference between third power storage unit 12c and fourth power storage unit 12d becomes equal to or smaller than the fifth predetermined value, and power supply from third power storage unit 12c and fourth power storage unit 12d to load 38 can be easily and efficiently switched to. In addition, while power is being supplied from third power storage unit 12c and fourth power storage unit 12d to load 38, first power storage unit 12a and second power storage unit 12b that have been discharged earlier can be charged, and therefore power device 10 can be used efficiently.

[0132] To explain in more detail, by drawing power for each two power storage units 12 connected in parallel to the load 38, control is easier than drawing power from four or more power storage units 12 connected in parallel to the load 38. Also, while drawing power for each two power storage units 12, it is possible to replace a power storage unit 12 from which power is not being drawn (a power storage unit 12 that is low on electricity).

[0133] In addition, when the battery voltage difference or SOC difference between the first power storage unit 12a and the third power storage unit 12c exceeds a third predetermined value or a sixth predetermined value (second predetermined value), the ECU 22 controls the multiple interrupters 16 to maintain a state in which power is transmitted via the first power transmission path 14a connected to the first power storage unit 12a and the second power transmission path 14b connected to the second power storage unit 12b, while prohibiting the transmission of power via the third power transmission path 14c connected to the third power storage unit 12c.

[0134] This makes it possible to prevent a circulating current (overcurrent) from flowing from the first and second power storage units 12a and 12b to the third power storage unit 12c, while supplying power from the first and second power storage units 12a and 12b to the load 38 to discharge the power, thereby making it possible to use up the power in the first and second power storage units 12a and 12b.

[0135] Furthermore, when the battery voltage difference or SOC difference between two power storage units 12 is within any one of first to sixth predetermined values ​​(third predetermined value), ECU 22 controls multiple interrupting units 16 so that a power storage unit 12 having a battery voltage or SOC within the predetermined value is connected to connection unit 20. On the other hand, when the battery voltage difference or SOC difference between two power storage units 12 exceeds the predetermined value, ECU 22 controls multiple interrupting units 16 so as to connect any one of power storage units 12 to connection unit 20 or to maintain the current connection state between power storage unit 12 and connection unit 20.

[0136] This makes it possible to reliably prevent the occurrence of a circulating current (overcurrent) and interruption of the power supply to the load 38.

[0137] In this case, the power storage units 12 are power storage devices that are detachable from the power device 10, and the ECU 22 performs a numbering process for the power storage units 12 when at least one power storage unit 12 is replaced.

[0138] This allows efficient supply of power from a plurality of power storage units 12 to load 38.

[0139] The second embodiment relates to a power device 80 having a plurality of power storage units 12, a plurality of power transmission paths 86 connected to the plurality of power storage units 12, and a connection unit 20 that connects the plurality of power storage units 12 in parallel via the plurality of power transmission paths 86. The power device 80 has a plurality of first power transmission paths 86a that form a plurality of power transmission paths 86 and connect a plurality of power storage units 12 and the connection unit 20, a first interruption section 84a that is arranged on the plurality of first power transmission paths 86a and connects and disconnects the power storage unit 12 and the connection unit 20, a plurality of second power transmission paths 86b that form the plurality of power transmission paths 86 and connects a portion of the first power transmission paths 86a that is closer to the power storage unit 12 than the first interruption section 84a to the connection unit 20 and has portions on the connection unit 20 side connected to each other, second interruption sections 84b that are arranged on the plurality of second power transmission paths 86b and connect and disconnect the power storage unit 12 and the connection unit 20, and a one-way rectification section 82 that is arranged between a portion of the plurality of second power transmission paths 86b on the connection unit 20 side and the connection unit 20.

[0140] The second embodiment relates to a control method for a power device 80 in which a plurality of power storage units 12 are connected in parallel to a connection unit 20 via a plurality of power transmission paths 86. In the control method, the plurality of power transmission paths 86 are composed of a plurality of first power transmission paths 86a that connect the plurality of power storage units 12 and the connection unit 20 and in which a first interruption portion 84a that connects the power storage units 12 and the connection unit 20 is disposed, and a plurality of second power transmission paths 86b that connect a portion of the first power transmission paths 86a closer to the power storage units 12 than the first interruption portion 84a to the connection unit 20 and in which portions on the connection portion 20 side are connected to each other and in which a second interruption portion 84b that connects the power storage units 12 and the connection unit 20 is disposed. In this case, a one-way rectifier 82 is arranged between the connection portion 20 side of the multiple second power transmission paths 86b and the connection portion 20, and the power device 80 has multiple groups, each group consisting of a first power transmission path 86a, a first interruption portion 84a, a second power transmission path 86b and a second interruption portion 84b.

[0141] The control method includes the steps of connecting the first interrupting portion 84a of one set to a connected state as shown in FIG. 13B, connecting the second interrupting portion 84b of one set to a connected state as shown in FIG. 14A, connecting the first interrupting portion 84a of one set to a disconnected state as shown in FIG. 14B, connecting the first interrupting portion 84a of the other set to a connected state as shown in FIG. 15A, and connecting the second interrupting portion 84b of one set to a disconnected state as shown in FIG. 15B.

[0142] In the second embodiment, the one-way rectifier 82 is provided in the power transmission path 86. Therefore, even if the interrupters 84 (first interrupter 84a, second interrupter 84b) of the multiple power transmission paths 86 are connected, it is possible to prevent a circulating current (overcurrent) from flowing from the fully charged storage unit 12 to the storage unit 12 in the low-power state. Furthermore, when the interrupters 84 of the multiple power transmission paths 86 are connected, power is output from the fully charged storage unit 12 via the connection unit 20. This makes it possible to avoid a time period during which no voltage is transmitted (output) (a time period during which power supply to the load 38 is interrupted). Furthermore, the simple configuration in which the interrupters 84 (second interrupter 84b) and the one-way rectifier 82 are arranged in series in the power transmission path 14 is inexpensive and easy to control.

[0143] Here, the power device 80 according to the second embodiment further includes an ECU 22 (controller) that controls the first interrupter 84a and the second interrupter 84b to switch between a connected state in which the power storage unit 12 and the connection unit 20 are connected, and a disconnected state in which the power storage unit 12 and the connection unit 20 are disconnected. In this case, the power device 80 includes a plurality of sets, each set being made up of the first power transmission path 86a, the first interrupter 84a, the second power transmission path 86b, and the second interrupter 84b.

[0144] When the ECU 22 transitions from a state in which power is transmitted only through the first power transmission path 86a of one set to a state in which power is transmitted only through the first power transmission path 86a of the other set because the first interruption part 84a of one set is in a connected state and the first interruption part 84a of the other set is in a disconnected state, the ECU 22 sets the second interruption part 84b of one set to a connected state and then the first interruption part 84a of one set to a disconnected state, and then sets the first interruption part 84a of the other set to a connected state and then the second interruption part 84b of the one set to a disconnected state.

[0145] This makes it possible to switch the power supply from the storage unit 12 connected to one set to the load 38 to the power supply from the storage unit 12 connected to the other set to the load 38, while avoiding the occurrence of circulating current (overcurrent) and the occurrence of periods when the power supply to the load 38 is interrupted.

[0146] In the power devices 10, 80 according to the first and second embodiments, the unidirectional rectifiers 18, 82 are rectifiers that pass a current so as to transmit power only in the direction from the power storage unit 12 to the connection unit 20.

[0147] This makes it possible to prevent a circulating current (overcurrent) from flowing and supply power from the power storage unit 12 to the load 38 without controlling the one-way rectifiers 18 and 82 in any way. Furthermore, the cost can be kept low compared to the case where a DC-DC converter is installed.

[0148] It should be noted that the present invention is not limited to the above-described embodiment, and various configurations can be adopted based on the contents of this specification. [Explanation of symbols]

[0149] 10, 60, 80...power device 12...electricity storage unit 14, 86... power transmission path 14a, 86a... first power transmission path 14b, 86b... second power transmission path 16, 84... interrupted portion 16a, 84a...First interrupted portion 16b, 84b...Second interrupted portion 18, 82...One-way rectifier section 20...Connection section

Claims

1. A power device including a plurality of power storage units, a plurality of power transmission paths connected to the plurality of power storage units, and a connection unit connecting the plurality of power storage units in parallel via the plurality of power transmission paths, a plurality of first power transmission paths that constitute the plurality of power transmission paths and connect the plurality of power storage units and the connection unit; a first connecting / disconnecting unit that is disposed in a plurality of the first power transmission paths and connects / disconnects the power storage unit and the connection unit; a plurality of second power transmission paths that constitute the plurality of power transmission paths, connect a portion of the first power transmission path that is closer to the power storage unit than the first intermittent portion to the connection portion, and have portions on the connection portion that are connected to each other; a second interrupting unit disposed in each of the second power transmission paths and configured to connect and disconnect the power storage unit and the connection unit; a one-way rectifier disposed between the points where the second power transmission paths are connected to each other on the connection portion side and an input side terminal of the connection portion; A power device having

2. 2. The power device according to claim 1, a control unit that controls the first interrupter and the second interrupter to switch between a connection state in which the power storage unit and the connection unit are connected and a disconnection state in which the power storage unit and the connection unit are disconnected, the power device includes a plurality of sets, each set being the first power transmission path, the first interruption unit, the second power transmission path, and the second interruption unit; The control unit is When the first interrupting portion of one set is in a connected state and the first interrupting portion of the other set is in a disconnected state, a transition is made from a state in which power is transmitted only through the first power transmission path of the one set to a state in which power is transmitted only through the first power transmission path of the other set, A power device which sets the second interruption part of one of the sets to a connected state, then sets the first interruption part of the one of the sets to a disconnected state, and then sets the first interruption part of the other set to a connected state, and then sets the second interruption part of the one of the sets to a disconnected state.

3. 3. The power device according to claim 1, a control unit that controls the first interrupting unit and the second interrupting unit to switch between a connection state in which the power storage unit and the connection unit are connected and a disconnection state in which the power storage unit and the connection unit are disconnected, thereby controlling the transmission of power through the plurality of power transmission paths; The control unit is numbering the plurality of power storage units in order starting from the power storage unit having the largest voltage or the largest amount of stored power; A power device that controls the first and second interrupting units so that, when transmitting power through two of the multiple power transmission paths, the power transmission path is transmitted through the power transmission path connected to a first storage unit and the power transmission path connected to a second storage unit.

4. 4. The power device according to claim 3, The control unit is When a voltage difference or a power storage amount difference between the third power storage unit and the fourth power storage unit exceeds a first predetermined value, A power device that controls a plurality of first interrupting units and a plurality of second interrupting units to transmit power via a plurality of the power transmission paths connected to the first to third power storage units before switching from a state in which power is transmitted via the power transmission path connected to the first power storage unit and the power transmission path connected to the second power storage unit to a state in which power is transmitted via the power transmission path connected to the third power storage unit and the power transmission path connected to the fourth power storage unit.

5. 3. The power device according to claim 2, the plurality of power storage units are power storage devices that are detachable from the power device, the control unit, when at least one of the power storage units is replaced, performs a numbering process on the plurality of power storage units and controls the sets of the power storage units in an order assigned by the numbering process; The order of the power device does not change until the numbering process is performed again.

6. In the power device according to any one of claims 1 to 5, The electric power device is provided with one of the unidirectional rectifier units.

7. A control method for a power device in which a plurality of power storage units are connected in parallel to a connection unit via a plurality of power transmission paths, comprising: The plurality of power transmission paths include a plurality of first power transmission paths connecting the plurality of power storage units and the connection unit, the first connection / disconnection units being disposed to connect and disconnect the power storage units and the connection unit; a plurality of second power transmission paths that connect a portion of the first power transmission path closer to the power storage unit than the first interruption portion to the connection portion, the portions of the first power transmission path closer to the connection portion being connected to each other, and in which a second interruption portion that interrupts the power storage unit and the connection portion is disposed; It is composed of a one-way rectifier is disposed between the points where the second power transmission paths are connected to each other on the connection portion side and an input side terminal of the connection portion, a first step of connecting the first intermittent unit of one of the sets to a connected state when the power device has a plurality of sets, each set being made up of the first power transmission path, the first intermittent unit, the second power transmission path, and the second intermittent unit; a second step of connecting the second interrupting unit of the one set to a connected state when a voltage or an amount of stored power of the power storage unit of the one set is reduced due to use of power after the first step; a third step of setting the first interrupting portion of the one set in an interrupted state after the second step; a fourth step of connecting the first interrupting unit of the other set to a connected state when the voltage or the amount of stored power of the power storage unit of the one set has decreased to a discharge lower limit threshold value after the third step; a fifth step of interrupting the second interrupting unit of the one set when the power storage unit of the one set runs out of power after the fourth step; A method for controlling a power device comprising the steps of:

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