JP2022117722A - Power source control device - Google Patents

Abstract

To provide a power source control device in which imbalance among a plurality of batteries can be easily redressed.SOLUTION: A power source control deice 10 is used for a power source system 3 in which a plurality of batteries (first high-voltage battery 71, second high-voltage battery 72) constituting a high-voltage battery 70 can be connected at least in parallel. The power source control deice 10 includes a power conversion unit 40 that performs power conversion between the first high-voltage battery 71 and the second high-voltage battery 72, and a control unit 12 that controls the power conversion unit. The control unit adjusts a voltage across one of the batteries and a voltage across the other battery by causing the power conversion unit to perform a step-down operation or a step-up operation.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a power control device.

Patent Literature 1 discloses a battery control device mounted on an electric vehicle. The battery control device disclosed in Patent Document 1 connects a plurality of batteries in parallel when the electric vehicle is running, and connects the plurality of batteries in series when the batteries are charged by an external power supply device.

JP 2018-85790 A JP 2012-50158 A

In the system disclosed in Patent Document 1, there is a concern that a state imbalance may occur between one of the batteries and the other battery, so in this type of system, a technology that easily corrects the imbalance of multiple batteries is applied. It is hoped that

The present disclosure provides a conversion device that facilitates correcting the imbalance of multiple batteries.

A power supply control device, which is one of the present disclosure,
A power supply control device used in a power supply system in which a plurality of batteries can be connected at least in parallel,
a power conversion unit that performs power conversion between one of the plurality of batteries and the other battery;
a control unit that controls the power conversion unit;
has
The control unit causes the power conversion unit to perform a step-down operation or a step-up operation to adjust the voltage across the one battery and the voltage across the other battery.

A power control apparatus that is one aspect of the present disclosure facilitates correcting imbalances among multiple batteries.

FIG. 1 is a block diagram schematically illustrating an in-vehicle system including a power control device according to the first embodiment. FIG. 2 is a circuit diagram specifically showing the power supply control device of the first embodiment and its periphery. FIG. 3 is a block diagram schematically exemplifying an in-vehicle system including the power control device of the second embodiment. FIG. 4 is a circuit diagram specifically showing the power supply control device of the second embodiment and its periphery. FIG. 5 is a block diagram schematically exemplifying an in-vehicle system including the power control device of the third embodiment. FIG. 6 is a circuit diagram specifically showing the power supply control device of the fourth embodiment and its periphery.

Embodiments of the present disclosure are listed and illustrated below. The features [1] to [13] exemplified below may be combined in any way within a consistent range.

[1] A power supply control device used in a power supply system in which a plurality of batteries can be connected at least in parallel,
a power conversion unit that performs power conversion between one of the plurality of batteries and the other battery;
a control unit that controls the power conversion unit;
has
A power supply control device, wherein the control unit causes the power conversion unit to perform a step-down operation or a step-up operation to adjust a voltage across the one battery and a voltage across the other battery.

In the power supply control device of [1] above, the control unit can control the power conversion unit to adjust the voltage across one battery and the voltage across the other battery. Therefore, this power control apparatus is easy to correct the imbalance of a plurality of batteries.

[2] The power control device described in [1] above has the following features. The power supply system has a switching unit that switches the connection state of the one battery and the other battery between series connection and parallel connection. A predetermined portion of the power conversion section is also used as the switching section.

The power supply system to which the power control device of [2] above is intended is one in which the connection state of one battery and another battery is switched between series connection and parallel connection, and the batteries tend to become unbalanced. There are concerns about the adverse effects of this situation. The power control apparatus described above is more useful because it can correct the imbalance of the batteries in such a power system. Moreover, since the power supply control device can also use at least a part of the power conversion unit as a part of the switching unit that switches the series/parallel connection of the plurality of batteries, the device can be simplified.

[3] The power control device described in [2] above has the following features. The power conversion section includes a plurality of semiconductor switches and an inductor, and has a DCDC converter that performs voltage conversion by turning on and off the plurality of semiconductor switches. The switching unit has a mechanical relay. The plurality of semiconductor switches includes a parallel switch connected in parallel with the mechanical relay. The parallel switch and the mechanical relay are provided in parallel in a path between the negative electrode of the one battery and the positive electrode of the other battery. Conduction is established between the negative electrode of the one battery and the positive electrode of the other battery when the mechanical relay is on.

The power supply control device of [3] above can perform a high-speed switching operation by a semiconductor switch when voltage conversion is performed between batteries by a DCDC converter. On the other hand, when one battery and another battery are switched to a series connection, the mechanical relay can be turned on to allow conduction between the negative electrode of one battery and the positive electrode of the other battery. In other words, conduction during series connection can be achieved by a component different from the switch that performs high-speed switching operation.

[4] The power supply control device described in [3] above has the following features. The DCDC converter has a bridge circuit. The bridge circuit includes a first series section in which a first semiconductor switch and a second semiconductor switch of the plurality of semiconductor switches are connected in series, and a third semiconductor switch and a fourth semiconductor switch of the plurality of semiconductor switches. A second series section in which a semiconductor switch is connected in series, and the inductor. The first series section is connected in parallel with the one battery. One end of the first semiconductor switch is electrically connected to the positive electrode of the one battery. One end of the second semiconductor switch is electrically connected to the negative electrode of the one battery. The second series section is connected in parallel with the other battery. One end of the third semiconductor switch is electrically connected to the positive electrode of the other battery. One end of the fourth semiconductor switch is electrically connected to the negative electrode of the other battery. One end of the inductor is electrically connected to a portion between the first semiconductor switch and the second semiconductor switch in the first series section. The other end of the inductor is electrically connected to a portion between the third semiconductor switch and the fourth semiconductor switch in the second series section. One of the mechanical relays is connected in parallel with the second semiconductor switch. Another mechanical relay is connected in parallel with the third semiconductor switch. When the one mechanical relay and the other mechanical relay are switched to the ON state, the switching unit switches the one battery through the one mechanical relay, the other mechanical relay, and the inductor. The negative electrode and the positive electrode of the other battery are electrically connected to connect the one battery and the other battery in series.

The power supply control device of [4] above enables voltage conversion between the two batteries by means of an H-bridge type bridge circuit, while efficiently utilizing the inductors and conductive paths of the bridge circuit to switch to series connection. make it possible.

[5] The power control device described in [2] above has the following features. The power conversion section has a DCDC converter that includes a plurality of switches and an inductor, and performs voltage conversion by turning on and off the plurality of switches. The plurality of switches includes a dual-purpose switch that is also used as the switching unit. The dual-purpose switch is provided on a path between the negative electrode of the one battery and the positive electrode of the other battery. When the dual-purpose switch is switched to an ON state, the switching unit establishes electrical continuity between the negative electrode of the one battery and the positive electrode of the other battery, thereby connecting the one battery and the other battery in series.

In the power supply control device of [5] above, the H-bridge type bridge circuit enables voltage conversion between the two batteries, while efficiently using the inductor and switch (double-purpose switch) of the bridge circuit for series connection. allow to switch. In particular, in the above power supply control device, some switches are used for both series-parallel switching and voltage conversion. be able to.

[6] The power control device described in any one of [2] to [5] above has the following characteristics. The switching unit includes a first relay interposed between the positive electrode of the one battery and the positive electrode of the other battery, and a second relay interposed between the negative electrode of the one battery and the negative electrode of the other battery. a relay; By switching the first relay and the second relay to the ON state, the positive electrode of the one battery and the positive electrode of the other battery are short-circuited, and the negative electrode of the one battery and the negative electrode of the other battery are connected. The one battery and the other battery are connected in parallel by shorting. When the power conversion unit performs the step-down operation or the step-up operation, the control unit gives an instruction to switch the first relay and the second relay to an OFF state, and The short circuit between the positive electrodes of the batteries is released, and the short circuit between the negative electrodes of the one battery and the negative electrodes of the other battery is released.

The power supply control device of [6] above can switch the one battery and the other battery to a parallel state by short-circuiting the positive electrode and the negative electrode by the first relay and the second relay, respectively. On the other hand, when power conversion is performed between batteries, this power supply control device switches the first relay and the second relay to the OFF state to release the short circuit, and can correct the imbalance while suppressing the sudden current. .

[7] The power control device described in any one of [1] to [6] above has the following characteristics. The power system has a power path. A first interrupting section that switches between a first interrupted state and a first released state is provided between the electrode of the one battery and the power path, and is provided between the electrode of the other battery and the power path. is provided with a second cutoff section that switches between a second cutoff state and a second released state, and when the first cutoff section is in the first cutoff state, continuity between the one battery and the power path is provided. is interrupted, and on the condition that the first interrupter is in the first released state, conduction between the one battery and the power path is permitted, and the second interrupter is in the second interrupted state. When the continuity between the other battery and the power path is interrupted, and the second disconnecting section is in the second release state, the continuity between the other battery and the power path is established. is allowed, and the power conversion unit performs a pair of first conductive paths, a pair of second conductive paths, and a step-down operation and a step-up operation between the pair of first conductive paths and the pair of second conductive paths and a conversion circuit for performing The pair of first conductive paths are configured to be short-circuited to both ends of the one battery when the first cutoff portion is in the first cutoff state and when the first cutoff portion is in the first released state. The pair of second conductive paths are configured to be short-circuited to both ends of the other battery when the second cutoff portion is in the second cutoff state and when the second cutoff portion is in the second released state.

The power supply control device of [7] above can perform an adjustment operation by the power converter even in a state where the power supply to the power path is interrupted by the first interrupter or the second interrupter.

[8] The power control device described in [1] above or the power control device cited in [1] in the power control device described in [7] above has the following features. The power supply system has a switching unit. The switching unit performs a first switching operation to switch the connection state of the one battery and the other battery between a series connection and a parallel connection, and the power conversion unit performs the first switching operation so that at least the switching unit performs the first switching operation. A second switching operation is performed to switch the connection state of the one battery and the other battery between a series connection state and a series disconnection state when not performed.

In the power supply control device of [8] above, the power conversion unit can perform the switching operation even when the switching unit cannot or does not perform the switching operation. Therefore, redundancy is further enhanced.

[9] The power control device according to the above [3] or [4], or the power control citing [3] in the power control device according to any one of the above [6] to [8] The device has the following features. A resistance value of the mechanical relay when the mechanical relay is on is smaller than a resistance value of the parallel relay when the parallel relay is on.

The power supply control device of [9] above can perform on-off operation at high speed by the semiconductor switch during power conversion, and when connecting two batteries in series, the on-operation of the mechanical relay It can be connected in series with reduced loss.

[10] The power control device described in any one of [1] to [9] above has the following characteristics. The control unit causes the power conversion unit to reduce a difference in output voltage or state of charge (SOC) between the one battery and the other battery when a predetermined start condition is satisfied. .

The power supply control device of [10] above can surely correct the imbalance of the output voltages of the two batteries or the imbalance of the SOC.

[11] The power supply control device described in [10] above has the following features. A switching unit for switching a connection state of the one battery and the other battery between a series connection and a parallel connection. When the one battery and the other battery are not connected in parallel, the control unit causes a difference in output voltage or SOC (State Of Charge) between the one battery and the other battery to be less than a certain value. On this condition, the one battery and the other battery are switched to parallel connection.

The power control device of [11] above can prevent switching to parallel connection in a state where the difference between the output voltages or SOCs of the two batteries is greater than a certain value. Therefore, this power supply control device can prevent excessive current from flowing from one battery to the other battery when switched to parallel connection.

[12] The power control device described in any one of [1] to [11] above has the following features. The power supply system has a power path through which power is supplied from the plurality of batteries. The switching unit and the power conversion unit are in a first state that allows power to be supplied from both the one battery and the other battery to the power path, and a state that allows power to be supplied from the one battery to the power path. a second state in which the supply of power from the other battery to the power path is interrupted; and a third state that cuts off the supply of power from the battery to the power path.

The power supply control device of [12] above can switch which battery to output to the power path by the switching unit and the power conversion unit. For example, this power supply control device is capable of outputting from the other battery instead of the battery when a situation occurs in which output from one of the batteries should not be performed or cannot be output.

[13] The power control device described in [12] above has the following features. The control unit determines whether power supply from each of the one battery and the other battery is in an abnormal state, and determines whether power supply from both the one battery and the other battery is in an abnormal state. The switching unit and the power conversion unit are set to the first state on the condition that the abnormal state is not present, the power supply from the other battery is in the abnormal state, and the power supply from the one battery is not in the abnormal state. the switching unit and the power conversion unit are set to the second state in the above case, and when the power supply from the one battery is in the abnormal state and the power supply from the other battery is not in the abnormal state, the switching unit and Let the said power conversion part be a said 3rd state.

The power supply control device of [13] above can supply power from both batteries to the power path after confirming that both batteries are not in an abnormal state. Further, this power supply control device can continue power supply using the one battery when the other battery is in an abnormal state, unless the one battery is in an abnormal state. Similarly, when one battery is in an abnormal state, this power supply control device can continue power supply using the other battery unless the other battery is in an abnormal state.

<First embodiment>
(In-vehicle system overview)
FIG. 1 illustrates a power system 3 including a power control device 10 according to the first embodiment of the present disclosure. The power system 3 is part of the in-vehicle system 2 . The in-vehicle system 2 is an electrical system mounted in a vehicle, and is a system that supplies power to a load based on power from a power source such as a battery.

Vehicles in which the in-vehicle system 2 is installed are, for example, vehicles such as PHEVs (Plug-in Hybrid Electric Vehicles) and EVs (Electric Vehicles). The in-vehicle system 2 includes a power supply system 3, a driving section 4, a high voltage load 5, a low voltage load 8, and the like. The power supply system 3 includes a power control device 10, a low voltage battery 74, a high voltage battery 70, and the like.

Drive unit 4 includes an inverter 7 and a motor 6 . The inverter 7 generates AC power (for example, three-phase AC) from DC power based on power supplied from the high-voltage battery 70 and supplies the AC power to the motor 6 . The motor 6 is, for example, a main machine system motor. The motor 6 is a device that rotates based on the power supplied from the high-voltage battery 70 and applies rotational force to the wheels of the vehicle.

High-voltage load 5 is a load that can operate with a relatively high voltage based on power from high-voltage battery 70 . In the example of FIG. 1, the high voltage load 5 is electrically connected to the power paths 81,82. The high-voltage load 5 is, for example, an air conditioner, a heater, or the like, and may be an electric device other than these.

The low-voltage loads 8 are various electric devices for vehicles that can operate with a relatively low voltage. The low-voltage load 8 is, for example, a starter motor, an alternator, a radiator cooling fan, and the like. Low voltage loads 8 may include electric power steering systems, electric parking brakes, lighting, wiper drives, navigation devices, and the like.

In this specification, the term "while the vehicle is running" includes a state in which the vehicle in which the in-vehicle system 2 is mounted is moving due to the operation of the motor 6 or the like, but is not limited to the state in which the vehicle is moving. When the vehicle is running, it includes a state in which the vehicle moves when the accelerator is stepped on. When the vehicle is running, it includes a state in which power is being supplied to any or all of the low-voltage loads 8 while the vehicle is stopped without moving. If the vehicle is a PHEV, the idling state of the engine is included when the vehicle is running.

The power supply system 3 is a system in which a first high-voltage battery 71 and a second high-voltage battery 72, which are examples of a plurality of batteries, are switched between serial connection and parallel connection. The power supply system 3 has a low-voltage battery 74 , a high-voltage battery 70 , a power control device 10 , and a voltage converter 60 .

When an external AC power supply (not shown) is connected to the vehicle, the power supply system 3 can charge the high voltage battery 70 and the low voltage battery 74 based on the AC power supplied from the external AC power supply. The vehicle has a connection terminal (not shown) to which an external AC power supply is connected, and the external AC power supply (not shown) can be connected to the connection terminal.

In the power supply system 3, a quick charger is connected to the connection terminals of the vehicle, and a voltage (for example, 800 V) exceeding the voltage specification of each of the first high voltage battery 71 and the second high voltage battery 72 is supplied from the quick charger. In this case, a DC voltage (for example, 800 V) exceeding the voltage specification of each of the first high-voltage battery 71 and the second high-voltage battery 72 is applied between the conductive paths 101 and 102 via a circuit (not shown). In this case, the control unit 12 can control the switching unit 30 (FIG. 2) to directly connect the first high voltage battery 71 and the second high voltage battery 72 . Details of the switching unit 30 will be described later.

On the other hand, in the power supply system 3, a quick charger is connected to the connection terminals of the vehicle, and a voltage (for example, 400 V) matching the voltage specifications of the first high voltage battery 71 and the second high voltage battery 72 is supplied from the quick charger. is supplied, a DC voltage (for example, 400 V) that meets the voltage specifications of the first high voltage battery 71 and the second high voltage battery 72 is applied between the conductive paths 101 and 102 via a circuit not shown. be done. In this case, the control unit 12 can control the switching unit 30 (FIG. 2) to connect the first high voltage battery 71 and the second high voltage battery 72 in parallel.

Power paths 81 and 82 are paths for supplying power from high-voltage battery 70 to inverter 7 . The power path 81 is a conductive path electrically connected to the positive electrode of the first high voltage battery 71 . Power path 82 is a conductive path that is electrically connected to ground. A fuse 97 is provided in the power path 82 . The fuse 97 cuts off the energization of the power path 82 when excessive current flows through the power path 82 .

The high voltage battery 70 includes a plurality of batteries, specifically a first high voltage battery 71 and a second high voltage battery 72 . Both the first high-voltage battery 71 and the second high-voltage battery 72 correspond to examples of batteries. The first high-voltage battery 71 corresponds to an example of one battery. The second high voltage battery 72 corresponds to an example of another battery. The high-voltage battery 70 is a power supply in which the first high-voltage battery 71 and the second high-voltage battery 72 are switched between series connection and parallel connection by a switching operation of the switching unit 30, which will be described later. High-voltage battery 70 is configured to be chargeable and dischargeable. A high-voltage battery 70 outputs a high voltage (for example, approximately 300 V) for driving the drive unit 4 . The output voltages of the first high-voltage battery 71 and the second high-voltage battery 72 when fully charged are higher than the output voltage of the low-voltage battery 74 when fully charged. The first high-voltage battery 71 and the second high-voltage battery 72 may be composed of lithium ion batteries, or may be composed of other types of storage batteries.

The positive electrode of the first high-voltage battery 71 is electrically connected to the power path 81 and the conductive path 51A and has the same potential as the power path 81 and the conductive path 51A. The negative electrode of the first high-voltage battery 71 is electrically connected to the conductive path 51B and has the same potential as the conductive path 51B. A fuse 95 is provided between the negative electrode of the first high voltage battery 71 and the conductive path 51B. The positive electrode of the second high-voltage battery 72 is electrically connected to the conductive path 52A and has the same potential as the conductive path 52A. The negative electrode of the second high-voltage battery 72 is electrically connected to the conducting path 52B and the power path 82 and can be at the same potential as the conducting path 52B and the power path 82 . A fuse 96 is provided between the negative electrode of the second high voltage battery 72 and the conductive path 52B and the power path 82 .

The low-voltage battery 74 is configured to be chargeable and dischargeable. A low-voltage battery 74 supplies power to the low-voltage load 8 . The low-voltage battery 74 may be composed of a lead-acid battery, or may be composed of other types of storage batteries. The low-voltage battery 74 outputs a predetermined voltage (eg, 12V) when fully charged.

The voltage conversion unit 60 is a DCDC converter that performs voltage conversion between the power paths 81 and 82 and the conducting paths 83 and 84 . The voltage conversion unit 60 can perform a step-down operation using the DC voltage applied to the power paths 81 and 82 as an input voltage, and perform a voltage conversion operation to apply a target output voltage to the conduction paths 83 and 84 . The voltage conversion unit 60 performs a step-up operation using the DC voltage applied to the conduction paths 83 and 84 as an input voltage, and can also perform a voltage conversion operation to apply a target output voltage to the power paths 81 and 82 . The conductive path 83 is a conductive path electrically connected to the positive electrode of the low-voltage battery 74 and one end of the low-voltage load 8 . The conductive path 84 is a conductive path electrically connected to the negative electrode of the low-voltage battery 74 and the other end of the low-voltage load 8, for example, a conductive path electrically connected to ground.

(Configuration of power control device)
As shown in FIG. 1 , the power supply control device 10 mainly includes a power conversion section 40 , a control section 12 , a management device 17 and a switching section 30 .

The control unit 12 is a device that performs various controls. The control unit 12 has an arithmetic function, an information processing function, a memory function, and the like. The control unit 12 may be configured by a plurality of electronic control devices, or may be configured by a single electronic control device. Control unit 12 controls power conversion unit 40 . A specific example of control of the power conversion unit 40 by the control unit 12 will be detailed later. The control unit 12 causes the power conversion unit 40 to perform a step-down operation or a step-up operation to adjust the voltage across the first high voltage battery 71 (one battery) and the voltage across the second high voltage battery 72 (another battery).

The management device 17 has a function of monitoring the high voltage battery 70 . The management device 17 continuously detects the output voltage, SOC (State Of Charge), of each of the plurality of batteries (the first high voltage battery 71 and the second high voltage battery 72 ) that constitute the high voltage battery 70 . In the example of FIG. 2 , the management device 17 is configured as part of the power control device 10 , but the management device 17 may be a device provided outside the power control device 10 .

The power converter 40 is a device that converts power between the first high voltage battery 71 (one battery) and the second high voltage battery 72 (another battery). The power conversion unit 40 converts power input from one of the first high-voltage battery 71 and the second high-voltage battery 72 and outputs the power to the other side.

The power converter 40 is a non-insulated DCDC converter. The power converter 40 is an H-bridge bidirectional DCDC converter. The power conversion unit 40 has a plurality of semiconductor switches 41, 42, 43, 44 and an inductor 46, and performs voltage conversion by turning on and off the plurality of semiconductor switches 41, 42, 43, 44. The semiconductor switches 41, 42, 43, and 44 are, for example, N-channel FETs (Field Effect Transistors). The power converter 40 includes a bridge circuit 40Z. The bridge circuit 40Z has a first series section 40A and a second series section 40B. The first series section 40A is a circuit in which a semiconductor switch 41 (first semiconductor switch) and a semiconductor switch 42 (second semiconductor switch) are connected in series. The second series section 40B is a circuit in which a semiconductor switch 43 (third semiconductor switch) and a semiconductor switch 44 (fourth semiconductor switch) are connected in series.

The first series section 40A is connected in parallel to the first high voltage battery 71 (one battery). One end (drain) of the semiconductor switch 41 is electrically connected to the positive electrode of the first high voltage battery 71 . One end (source) of the semiconductor switch 42 is electrically connected to the negative electrode of the first high voltage battery 71 . In the example of FIG. 2, the drain of the semiconductor switch 41, the conductive path 51A, and the positive electrode of the first high-voltage battery 71 are short-circuited and brought to the same potential. In the example of FIG. 2, the source of the semiconductor switch 42, the conductive path 51B, and the negative electrode of the first high-voltage battery 71 are short-circuited and brought to the same potential. The second series section 40B is connected in parallel with the second high-voltage battery 72 . One end (drain) of the semiconductor switch 43 is electrically connected to the positive electrode of the second high voltage battery 72 . One end (source) of the semiconductor switch 44 is electrically connected to the negative electrode of the second high voltage battery 72 . In the example of FIG. 2, the drain of the semiconductor switch 43, the conductive path 52A, and the positive electrode of the second high-voltage battery 72 are short-circuited and brought to the same potential. In the example of FIG. 2, the source of the semiconductor switch 44, the conductive path 52B, and the negative electrode of the second high-voltage battery 72 are short-circuited and brought to the same potential.

One end of inductor 26 is electrically connected to a portion between semiconductor switch 41 and semiconductor switch 42 in first series section 40A. One end of the inductor 46 is at the same potential as the source of the semiconductor switch 41 and the drain of the semiconductor switch 42 . The other end of inductor 46 is electrically connected to a portion between semiconductor switch 43 and semiconductor switch 44 in second series section 40B. The other end of the inductor 46 has the same potential as the source of the semiconductor switch 43 and the drain of the semiconductor switch 44 .

Conductive path 51A is a conductive path electrically connected to power path 81 . Conductive path 52B is a conductive path electrically connected to power path 82 . When the relay 31 is on, the conductive path 51A and the conductive path 52A are short-circuited. direction is blocked. When the relay 32 is on, the conductive path 51B and the conductive path 52B are short-circuited. direction is blocked.

The switching unit 30 is a device that switches the connection state of the first high-voltage battery 71 and the second high-voltage battery 72 between series connection and parallel connection. In the configuration of FIG. 2 , a predetermined portion (the inductor 46 and the conductive path connected to the inductor 46 , etc.) of the power conversion section 40 is also used as the switching section 30 . The switching unit 30 has relays 31, 32, 33, and 34 which are mechanical relays. The semiconductor switch 42 (second semiconductor switch) and the semiconductor switch 43 (third semiconductor switch) are parallel switches. A relay 34 is connected in parallel with the semiconductor switch 42 . The relay 34 corresponds to an example of one mechanical relay. A relay 33 is connected in parallel with the semiconductor switch 43 . The relay 33 corresponds to an example of another mechanical relay. Semiconductor switch 42 and relay 34 are provided in parallel in a path between the negative electrode of first high voltage battery 71 and the positive electrode of second high voltage battery 72 . Semiconductor switch 43 and relay 33 are also provided in parallel in the path between the negative electrode of first high voltage battery 71 and the positive electrode of second high voltage battery 72 .

The switching unit 30 includes a relay 31 interposed between the positive electrode of the first high voltage battery 71 and the positive electrode of the second high voltage battery 72 . The relay 31 corresponds to an example of a first relay. The switching unit 30 includes a relay 32 interposed between the negative electrode of the first high voltage battery 71 and the negative electrode of the second high voltage battery 72 . The relay 32 corresponds to an example of a second relay. By switching the relays 31 and 32 to the ON state, the positive electrode of the first high-voltage battery 71 and the positive electrode of the second high-voltage battery 72 are short-circuited, and the negative electrode of the first high-voltage battery 71 and the negative electrode of the second high-voltage battery 72 are connected. short circuit.

The switching unit 30 also includes semiconductor switches 41 , 42 , 43 , 44 . The switching unit 30 switches the first high voltage battery 71 and the second high voltage battery 72 in parallel by switching the relays 31 and 32 to the ON state and switching the relays 33 and 34 and the semiconductor switches 41, 42, 43 and 44 to the OFF state. to connect. In the parallel state, energization through the inductor 46 between the negative electrode of the first high voltage battery 71 and the positive electrode of the second high voltage battery 72 is interrupted.

The switching unit 30 connects the first high voltage battery 71 and the second high voltage battery 72 in series by switching the relays 33 and 34 to the ON state and switching the relays 31 and 32 and the semiconductor switches 41 and 44 to the OFF state. In the switching unit 30 , the negative electrode of the first high voltage battery 71 and the positive electrode of the second high voltage battery 72 are electrically connected via the relays 34 and 33 and the inductor 46 by switching the relays 34 and 33 to the ON state. When the switching unit 30 switches to the series connection in this manner, the semiconductor switches 42 and 43 may be maintained in an ON state or may be maintained in an OFF state. The resistance value across the relay 34 when the relay 34 is in the ON state is smaller than the resistance value across the semiconductor switch 42 (between the drain and source) when the semiconductor switch 42 is in the ON state. The resistance value across the relay 33 when the relay 33 is in the ON state is smaller than the resistance value across the semiconductor switch 43 (between the drain and source) when the semiconductor switch 43 is in the ON state.

The power paths 81 and 82 are paths for supplying power from the first high voltage battery 71 and the second high voltage battery 72 . The switching unit 30 and the power conversion unit 40 switch to a first state that allows power to be supplied from both the first high voltage battery 71 and the second high voltage battery 72 to the power paths 81 and 82 . The first state is the state of series connection or the state of parallel connection described above. The switching unit 30 and the power conversion unit 40 allow power to be supplied from the first high voltage battery 71 to the power paths 81 and 82, and block power from the second high voltage battery 72 to the power paths 81 and 82. It also switches to the second state. The second state is, for example, a state in which the semiconductor switches 41, 42, 43 and 44 are all turned off and the relays 31, 32, 33 and 34 are all turned off. The switching unit 30 and the power conversion unit 40 allow power to be supplied from the second high-voltage battery 72 to the power paths 81 and 82, and block power from the first high-voltage battery 71 to the power paths 81 and 82. It also switches to the third state. The third state is, for example, a state in which all of the semiconductor switches 41, 42, 43 and 44 are turned off and all of the relays 32, 33 and 34 are turned off.

(charging operation)
The power supply control device 10 gives the first instruction to the switching unit 30 when performing series charging. For example, the control unit 12 controls the first high-voltage battery 71 and the second high-voltage battery 72 when a voltage exceeding the voltage specifications of each of the first high-voltage battery 71 and the second high-voltage battery 72 is applied between the conducting paths 101 and 102 by a charging device (not shown). When charging the second high-voltage battery 72 , the first instruction is given to the switching unit 30 . The first instruction is an instruction to connect the first high-voltage battery 71 and the second high-voltage battery 72 in series. is an instruction to turn off. In this case, current flows from conductive path 101 to power path 81, first battery, semiconductor switch 42, inductor 46, semiconductor switch 43, second battery, power path 82, and conductive path 102 in this order, and the two batteries are charged. be.

The power supply control device 10 gives the second instruction to the switching unit 30 when performing parallel charging. For example, the power supply control device 10 applies voltages of the voltage specifications of the first high voltage battery 71 and the second high voltage battery 72 between the conduction paths 101 and 102 by a charging device (not shown). When charging the second high-voltage battery 72 , the second instruction is given to the switching unit 30 . The second instruction is an instruction to connect the first high-voltage battery 71 and the second high-voltage battery 72 in parallel. is an instruction to turn off.

(imbalance control operation)
The power supply control device 10 determines whether or not a predetermined condition is satisfied at a predetermined determination time, and if the predetermined condition is satisfied at the determination time, a plurality of batteries (the first high-voltage battery 71 and the second high-voltage battery 72) to reduce the imbalance. The predetermined determination timing may be, for example, when the high-voltage battery 70 is connected in series, or may be another timing. For example, the control unit 12 may determine whether or not a predetermined condition is satisfied during vehicle start-up when the start switch of the vehicle is in an ON state, and the external AC power supply and the power supply control device 10 are electrically connected. It may be determined whether or not a predetermined condition is satisfied when the connection is made. In a representative example described below, the determination timing is "when the high-voltage battery 70 is connected in series while the vehicle start switch is in the ON state and the vehicle is being started."

Specifically, the control unit 12 determines whether or not the predetermined condition is satisfied at the determination time. The predetermined condition is, for example, that "among the plurality of batteries, the difference between the output voltage of any one of the batteries and the output voltage of the second high-voltage battery 72 has increased by a predetermined value or more". The output voltage of a battery is, for example, the potential difference between the negative electrode (the electrode with the lowest potential in the battery) and the positive electrode (the electrode with the highest potential in the battery) in the battery. In the example described below, the controller 12 determines that the absolute value of the difference (|Va−Vb|) between the output voltage Va of the first high-voltage battery 71 and the output voltage Vb of the second high-voltage battery 72 becomes equal to or greater than the threshold value V1. This is referred to as "that a predetermined condition has been established". Then, when |Va−Vb|≧V1 at the determination timing, the control unit 12 causes the power conversion unit 40 to perform the imbalance suppressing operation.

In the example of FIG. 1, the management device 17 controls the output voltage Va of the first high-voltage battery 71 and the output voltage Vb of the second high-voltage battery 72 when power is being supplied to itself (for example, while the vehicle is being started). are continuously monitored, and the output voltages Va and Vb are continuously provided to the control unit 12 . The management device 17 may periodically apply the output voltages Va and Vb to the control unit 12 at short time intervals, or may apply the output voltages Va and Vb to the control unit 12 when a predetermined condition is satisfied. good. The control unit 12 continuously monitors the output voltages Va and Vb by acquiring information on the output voltages Va and Vb transmitted from the management device 17 . The control unit 12 monitors the output voltages Va and Vb at the determination time and continuously determines whether or not |Va-Vb|≧V1. The control unit 12 may periodically determine whether or not |Va-Vb|≧V1 at short time intervals, and when a predetermined condition is satisfied, |Va-Vb|≧V1. It may be determined whether

If it is determined that |Va−Vb|≧V1 at the determination time, the control unit 12 causes the power conversion unit 40 to perform the imbalance suppression operation. The timing at which the power conversion unit 40 is caused to perform the imbalance suppression operation may be the determination timing described above, or may be another predetermined timing. When causing the power conversion unit 40 to perform the imbalance suppression operation, the control unit 12 puts the battery with the higher output voltage into the discharge state or the charging stop state, and charges the battery with the lower output voltage. The power conversion unit 40 is caused to perform power conversion so as to perform power conversion. In this way, the control unit 12 allows the plurality of batteries (the first high-voltage battery 71 and the second high-voltage battery 72) to reduce the difference between the output voltages Va and Vb.

When the control unit 12 causes the power conversion unit 40 to perform the step-down operation or the step-up operation as the imbalance suppression operation, the control unit 12 gives an instruction to switch the relays 31 and 32 to the off state, and switches the positive electrode of the first high-voltage battery 71 and the second electrode. The short circuit of the positive electrode of the second high voltage battery 72 is released, and the short circuit of the negative electrode of the first high voltage battery 71 and the negative electrode of the second high voltage battery 72 is released. While maintaining the state in which the short circuit between the positive electrodes and the short circuit between the negative electrodes of the first high-voltage battery 71 and the second high-voltage battery 72 are released, the control unit 12 causes the power conversion unit 40 to perform a step-down operation or a step-up operation. Let In this case, of the pair of conductive paths 51A and 51B and the pair of conductive paths 52A and 52B, the control unit 12 sets the pair of conductive paths having a higher voltage between the conductive paths as the input-side conductive paths. The power conversion unit 40 lowers the voltage applied to the input-side conductive path and applies it to the output-side conductive path so that the pair of conductive paths having the lower voltage is used as the output-side conductive path. buck operation. When voltage conversion is performed to correct the imbalance between batteries in this way, the target voltage on the output side can be changed so as to gradually increase from the voltage across the output-side conduction path at the start of the step-down operation. Alternatively, it may be a predetermined value, or may be a fixed value approximately equal to the input voltage at the start of the step-down operation.

For example, when the first high-voltage battery 71 and the second high-voltage battery 72 are disconnected from the parallel connection (the batteries are connected in series or the batteries are electrically disconnected), the pair of conductive paths 51A, When the voltage across 51B (the output voltage of the first high voltage battery 71) is higher than the voltage across the pair of conductive paths 52A and 52B (the output voltage of the second high voltage battery 72), the controller 12 controls the pair of conductive paths 51A. , 51B, and apply a target DC voltage (output voltage) between the pair of conductive paths 52A and 52B. let it happen In this case, the target DC voltage may be changed so as to gradually increase from the voltage value between the pair of conductive paths 52A and 52B at the start of the step-down operation, or may be a predetermined value. It may be a fixed value that is approximately the same as the input voltage at the start of the step-down operation.

After starting the imbalance suppression operation described above, the control unit 12 ends the imbalance suppression operation when the termination condition is satisfied. The termination condition may be, for example, when the absolute value of the difference between the output voltage Va of the first high voltage battery 71 and the output voltage Vb of the second high voltage battery 72 becomes equal to or less than a certain value smaller than the threshold value V1. It may be the case where Va=Vb, or it may be the case where a certain period of time has elapsed since the start of the imbalance suppression operation.

For example, the control unit 12 controls the first high-voltage battery 71 and the second high-voltage battery 72 in a state in which the first high-voltage battery 71 and the second high-voltage battery 72 are not connected in parallel (for example, a state in which they are connected in series or a state in which they are electrically disconnected). and the second high-voltage battery 72 are connected in parallel, the above-described imbalance suppression operation is started, and after this start, the difference between the output voltages of the first high-voltage battery 71 and the second high-voltage battery 72 is a constant value. The first high-voltage battery 71 and the second high-voltage battery 72 may be switched to parallel connection on condition that the voltage becomes less than.

(Abnormal response operation)
The control unit 12 may have a function of determining whether power supply from each of the first high-voltage battery 71 and the second high-voltage battery 72 is in an abnormal state. The control unit 12 may place the switching unit 30 and the power conversion unit 40 in the above-described first state on condition that the power supply from both the first high-voltage battery 71 and the second high-voltage battery 72 is not in an abnormal state. When the power supply from the second high-voltage battery 72 is in an abnormal state and the power supply from the first high-voltage battery 71 is not in an abnormal state, the control unit 12 may set the switching unit 30 and the power conversion unit 40 to the above-described second state. good. The control unit 12 may set the switching unit 30 and the power conversion unit 40 to the third state when the power supply from the first high voltage battery 71 is in an abnormal state and the power supply from the second high voltage battery 72 is not in an abnormal state. . In this way, it is possible to confirm that both batteries are not in an abnormal state and to supply power from both batteries to the power path. Further, when one of the first high-voltage battery 71 and the second high-voltage battery 72 is in an abnormal state, the power supply control device 10 can continue power supply using the other unless the other is in an abnormal state. can. The power supply control device 10 can further add such functions to the switching unit 30 and the power conversion unit 40 .

When performing the above-described abnormality handling operation (switching between the first state, the second state, and the third state), the "abnormal state of the power supply from the first high voltage battery 71" is the output voltage of the first high voltage battery 71 or the SOC may fall below the threshold for abnormality determination, or the voltage applied between the conductive paths 51A and 51B may fall below the threshold with the output of the second high-voltage battery 72 cut off. may “The power supply from the second high-voltage battery 72 is in an abnormal state” may be the case where the output voltage or SOC of the second high-voltage battery 72 drops below the threshold for abnormality determination, and the first high-voltage battery 71 It may be the case that the voltage applied between the conductive paths 52A and 52B drops below the threshold while the output of the circuit is cut off.

The following description relates to the effects of the first embodiment.
In the power supply control device 10 , the control section 12 can control the power conversion section 40 to adjust the voltage across the first high voltage battery 71 and the voltage across the second high voltage battery 72 . Therefore, this power supply control device 10 can easily correct the imbalance of the plurality of batteries.

The power supply system 3 targeted by the power supply control device 10 switches the connection state of the first high-voltage battery 71 and the second high-voltage battery 72 between series connection and parallel connection. 72 is likely to become unbalanced, and there is concern about adverse effects when it becomes unbalanced. The power supply control device 10 is more useful because it can correct the imbalance between the first high voltage battery 71 and the second high voltage battery 72 in such a power supply system 3 . Moreover, since the power supply control device 10 can also use at least a part of the power conversion section 40 as a part of the switching section 30 for switching the series-parallel connection of the first high-voltage battery 71 and the second high-voltage battery 72, the device can be simplified. can be improved.

When the power conversion unit 40 (DCDC converter) performs voltage conversion between the first high-voltage battery 71 and the second high-voltage battery 72, the power supply control device 10 can perform high-speed switching operation with the semiconductor switch. On the other hand, when the first high-voltage battery 71 and the second high-voltage battery 72 are switched to a series connection, the mechanical relay is turned on to establish electrical continuity between the negative electrode of the first high-voltage battery 71 and the positive electrode of the second high-voltage battery 72. can be made In other words, a component different from a switch that performs a high-speed switching operation can be used to achieve conduction during series connection, and in particular, the ON operation of the mechanical relay enables series connection with reduced loss.

The power supply control device 10 enables voltage conversion between both batteries by the H-bridge type bridge circuit 40Z, while efficiently using the inductor 46 and conductive path of the bridge circuit 40Z to switch to series connection. do.

The power supply control device 10 short-circuits the positive electrodes and the negative electrodes of the first high-voltage battery 71 and the second high-voltage battery 72 using the relay 31 (first relay) and the relay 32 (second relay), respectively. The second high voltage battery 72 can be switched to a parallel state. On the other hand, when power conversion is performed between the first high-voltage battery 71 and the second high-voltage battery 72, the power supply control device 10 switches the relays 31 and 32 to the OFF state to release the short circuit, thereby causing a rapid current flow. Imbalances can be corrected while containing them.

<Second embodiment>
The following description relates to the second embodiment.
3 and 4 show an example of the power control device 210 of the second embodiment. A power supply control device 210 of the second embodiment includes a power converter 240 instead of the power converter 40, a switching unit 230 as a separate device from the power converter 240, and relays 91A, 91B, and 92A. , 92B is the same as the power supply control device 10 of the first embodiment. The in-vehicle system 202 is the same as the in-vehicle system 2 ( FIG. 1 ) according to the first embodiment except that a power control device 210 is provided instead of the power control device 10 . The power supply system 203 is the same as the power supply system 3 ( FIG. 1 ) according to the first embodiment except that a power supply control apparatus 210 and a switching unit 230 are provided instead of the power supply control apparatus 10 .

As shown in FIG. 4 , the power supply system 203 has a switching section 230 . The switching unit 230 performs a first switching operation of switching the connection state of the first high-voltage battery 71 and the second high-voltage battery 72 between series connection and parallel connection. When the first high-voltage battery 71 and the second high-voltage battery 72 are connected in series, the switching unit 230 short-circuits the negative electrode of the first high-voltage battery 71 and the positive electrode of the second high-voltage battery 72 by turning on the relay 232 . By turning off the relays 231 and 233, the short circuit between the positive electrodes and the short circuit between the negative electrodes of both batteries are released. On the other hand, when the first high-voltage battery 71 and the second high-voltage battery 72 are connected in parallel, the switching unit 230 turns off the relay 232 to connect the negative electrode of the first high-voltage battery 71 and the positive electrode of the second high-voltage battery 72 . By releasing the short circuit between and turning on the relays 231 and 233, the positive electrodes and the negative electrodes of both batteries are short-circuited.

The power converter 240 is the same as the power converter 40 of the first embodiment except that the relays 31, 32, 33, and 34 are omitted. The power control device 210 can perform the same charging operation, imbalance suppression operation, and abnormality handling operation as in the first embodiment.

The power conversion unit 240 switches the connection state of the first high-voltage battery 71 and the second high-voltage battery 72 between series connection and series disconnection at least when the switching unit 230 is not performing the first switching operation described above. A second switching operation may be performed. For example, even in a state in which the relays 231, 232, and 233 of the switching unit 230 are all turned off and the energization through the relays 231, 232, and 233 is interrupted, the semiconductor switches 42 and 43 are turned on, and the semiconductor switches are turned on. 41 and 44 are turned off, the first high voltage battery 71 and the second high voltage battery 72 can be connected in series. On the other hand, if the relays 231 and 233 are turned on and the relay 232 is turned off, the first high voltage battery 71 and the second high voltage battery 72 can be connected in parallel. In this power supply control device 210, the power conversion section 240 can perform the switching operation even when the switching section 230 cannot or does not perform the series switching operation. Therefore, redundancy is further enhanced.

In the power supply system 203 of FIG. 3, a relay 91A is provided between the positive electrode of the first high voltage battery 71 and the power converter 240, and a relay 91B is provided between the negative electrode of the first high voltage battery 71 and the power converter 240. is provided. When the relay 91A is on, the positive electrode of the first high voltage battery 71 and the conductive path 51A are short-circuited to enable conduction through the relay 91A, and when the relay 91A is off, the first high voltage battery Conduction is cut off between the positive electrode of 71 and the conductive path 51A via the relay 91A. When the relay 91B is on, the negative electrode of the first high voltage battery 71 and the conducting path 51B are short-circuited to enable conduction through the relay 91B, and when the relay 91B is off, the first high voltage battery Conduction between the negative electrode of terminal 71 and conductive path 51B is interrupted via relay 91B. Similarly, a relay 92A is provided between the positive electrode of second high-voltage battery 72 and power conversion unit 240, and a relay 92B is provided between the negative electrode of second high-voltage battery 72 and power conversion unit 240. When the relay 92A is on, the positive electrode of the second high-voltage battery 72 and the conductive path 52A are short-circuited to enable conduction through the relay 92A, and when the relay 92A is off, the second high-voltage battery The electrical connection between the positive terminal of 72 and the conductive path 52A is interrupted via the relay 92A. When the relay 92B is on, the negative electrode of the second high voltage battery 72 and the conductive path 52B are short-circuited to enable conduction through the relay 92B, and when the relay 92B is off, the second high voltage battery Conduction between the negative electrode of 72 and conductive path 52B is interrupted via relay 92B. In addition, illustration of the relays 91A, 91B, 92A, and 92B is omitted in FIG.

<Third Embodiment>
The following description relates to the third embodiment.
FIG. 5 shows an example of the power control device 310 of the third embodiment. The power control device 310 of the third embodiment has the same configuration and functions as the power control device 210 of the second embodiment. The power supply control device 310 differs from the second embodiment only in the configuration of the target power supply system. The power supply system 303 of FIG. 5 is similar to the power supply system 203 (FIG. 3) except that the switching unit 230 and the fuses 95 and 96 are omitted, and the relays 391, 392, 393, 394, 395 and 396 and the resistors 397 and 398 are provided. ).

Between the positive electrode of the first high-voltage battery 71 and the power path 81, a relay 391 (first cutoff section) is provided that switches between an off state (first cutoff state) and an on state (first cutoff state). When the relay 391 (first cutoff section) is in the OFF state (first cutoff state), conduction between the first high voltage battery 71 and the power line 81 is cut off, and the relay 391 (first cutoff section) is in the ON state. Conduction between the first high-voltage battery 71 and the power line 81 is permitted under the condition that it is in the (first released state). Between the negative electrode of the first high-voltage battery 71 and the power line 82, relays 393 and 395 (first cutoff units) that switch between an off state (first cutoff state) and an on state (first cutoff state) are provided. . When both the relays 393 and 395 (first cutoff section) are in the OFF state (first cutoff state), the conduction between the first high voltage battery 71 and the power line 82 is cut off, and the relays 393 and 395 (first breaker) is in the ON state (first released state), conduction between the first high voltage battery 71 and the power line 82 is permitted. When relay 395 is on and relay 393 is off, current supply from first high voltage battery 71 is suppressed more than when relay 393 is on.

A relay 392 (second interrupter) that switches between an OFF state (second interrupted state) and an ON state (second released state) is provided between the positive electrode of the second high-voltage battery 72 and the power line 81 . When the relay 392 (second cutoff section) is in the OFF state (second cutoff state), conduction between the second high voltage battery 72 and the power line 81 is cut off, and the relay 392 (second cutoff section) is in the ON state. Conduction between the second high-voltage battery 72 and the power line 81 is allowed on condition that the state is (second release state). Between the negative electrode of the second high-voltage battery 72 and the power path 82, relays 394 and 396 (second interrupter) that switch between an OFF state (second interrupted state) and an ON state (second released state) are provided. . When both of the relays 394, 396 (second cutoff section) are in the OFF state (second cutoff state), the conduction between the second high voltage battery 72 and the power line 82 is cut off, and the relays 394, 396 (second breaker) is in the ON state (second release state), conduction between the second high-voltage battery 72 and the power line 82 is permitted. When relay 396 is on and relay 394 is off, current supply from second high-voltage battery 72 is suppressed more than when relay 394 is on.

The power converter 240 is the same as in the second embodiment, and includes a pair of conductive paths 51A and 51B (first conductive path), a pair of conductive paths 52A and 52B (second conductive path), and a pair of conductive paths 51A. , 51B and a bridge circuit 42Z (conversion circuit) that performs step-down operation and step-up operation between the pair of conducting paths 52A and 52B. The pair of conducting paths 51A and 51B (first conducting paths) are in the OFF state (first breaking state) even when the relays 391, 393, 395 (first breaking units) are in the ON state (first releasing state). The configuration is such that a short-circuit can occur between both ends of the first high-voltage battery 71 at any time. The pair of conducting paths 52A, 52B (second conducting paths) are in an OFF state (second interruption state) even when the relays 392, 394, 396 (second interruption units) are in an ON state (second release state). The configuration is such that short-circuiting can occur between both ends of the second high-voltage battery 72 even when the voltage is low. In other words, the power control device 310 can perform the adjustment operation by the power converter 240 even when the power supply to the power paths 81 and 82 is interrupted by the first interrupter and the second interrupter.

The power supply system 303 allows power to be supplied from both the first high voltage battery 71 and the second high voltage battery 72 to the power paths 81 and 82 by turning on and off the relays 391, 392, 393, 394, 395 and 396. A first state and a second state in which power supply from the first high voltage battery 71 to the power paths 81 and 82 is permitted and power supply from the second high voltage battery 72 to the power paths 81 and 82 is cut off. , and a third state in which the supply of power from the second high voltage battery 72 to the power paths 81 and 82 is permitted and the supply of power from the first high voltage battery 71 to the power paths 81 and 82 is cut off. The power control device 310 can perform an abnormality handling operation in the same manner as the power control device 10 of the first embodiment. That is, the control unit 12 determines whether the power supply from each of the first high-voltage battery 71 and the second high-voltage battery 72 is in an abnormal state, is not in an abnormal state, and the second state is set when the power supply from the second high voltage battery 72 is in an abnormal state and the power supply from the first high voltage battery 71 is not in an abnormal state. The third state can be set when the power supply from the first high voltage battery 71 is in an abnormal state and the power supply from the second high voltage battery 72 is not in an abnormal state. The determination of the abnormal state of the first high-voltage battery 71 and the second high-voltage battery 72 can be performed in the same manner as in the first embodiment.

<Fourth Embodiment>
The power control device 410 of the fourth embodiment differs from the power control device 10 of the first embodiment (FIG. 1) only in that the power conversion unit 40 is changed to the power conversion unit 440 and the switching unit 30 is changed to the switching unit 430. ). A power supply system 403 according to the fourth embodiment differs from the power supply system 3 ( FIG. 1 ) according to the first embodiment only in that the power conversion section 40 is changed to a power conversion section 440 .

As shown in FIG. 6, the power conversion section 440 of the power control device 410 differs from the power conversion section 40 of the first embodiment only in that the relays 33 and 34 are omitted. The power converter 440 includes a bridge circuit 40Z similar to that of the first embodiment. The power conversion unit 440 is also a DCDC converter that performs voltage conversion by turning on/off the plurality of semiconductor switches 41 , 442 , 443 and 44 . The semiconductor switch 442 is a semiconductor switch similar to the semiconductor switch 42, and differs from the semiconductor switch 42 only in that the relay is not connected in parallel. The semiconductor switch 443 is a semiconductor switch similar to the semiconductor switch 43, and differs from the semiconductor switch 43 only in that the relay is not connected in parallel.

Of the semiconductor switches 41 , 442 , 443 , 44 , the semiconductor switches 442 , 443 are dual-purpose switches that are also used as the switching unit 430 . The semiconductor switches 442 and 443 (double-purpose switches) are provided on the path between the negative electrode of the first high voltage battery 71 and the positive electrode of the second high voltage battery 72 . Switching unit 430 connects the negative electrode of first high voltage battery 71 and the positive electrode of second high voltage battery 72 by switching semiconductor switches 442 and 443 (multipurpose switches) to the ON state, thereby connecting first high voltage battery 71 and second high voltage battery 72 . 2 high-voltage batteries 72 are connected in series. When the switching unit 430 is connected in series, both the relays 31 and 32 and the semiconductor switches 41 and 44 are turned off as in the first embodiment. When switching unit 430 is connected in parallel, both relays 31 and 32 are turned on, and semiconductor switches 41, 442, 443 and 44 are all turned off.

The power supply control device 410 can perform the same charging operation, imbalance suppression operation, and abnormality handling operation as in the first embodiment.

The power control device 410 efficiently utilizes the inductor 46 and the switch (multipurpose switch) of the bridge circuit 40Z to enable switching to series connection. In particular, in the above power supply control device, some switches are used for both series-parallel switching and voltage conversion. be able to.

<Other embodiments>
The present disclosure is not limited to the embodiments illustrated by the above description and drawings. For example, the features of the embodiments described above or below can be combined in any consistent manner. Also, any feature of any of the embodiments above or below may be omitted if not explicitly indicated as essential. Furthermore, the embodiments described above may be modified as follows.

In the above-described embodiment, the management device 17 is configured to monitor the output voltage and SOC of the first high-voltage battery 71 and the second high-voltage battery 72. output voltage and SOC may be monitored.

In the above-described embodiment, the plurality of batteries is configured to be switched between series connection and parallel connection, but a configuration may be employed in which the plurality of batteries is always connected in parallel. For example, in the above-described embodiment, the switching unit may be omitted, and when power is supplied from both one battery and another battery, parallel connection may always be used to supply power, and the switch may not be switched to series connection.

In the above-described embodiment, one battery and another battery are provided as a plurality of batteries. It may be a configuration (a configuration with three or more batteries).

Although the relays 31, 32, 33, and 34 are mechanical relays in the above-described embodiments, they may be semiconductor relays.

In the above-described embodiment, the power supply control device 10 performs the imbalance suppression operation so as to reduce the difference in output voltage when the above-described start condition is satisfied, but the present invention is not limited to this example. When the start condition described above is satisfied, the power supply control device 10 may perform an imbalance suppression operation to reduce the difference in SOC (State Of Charge). In this case, in the above-described embodiment, a battery with a relatively high output voltage among the plurality of batteries is replaced with a battery with a relatively high SOC among the plurality of batteries, and a battery with a relatively high output voltage among the plurality of batteries is replaced. A low battery may be replaced with a battery with a relatively low SOC among the plurality of batteries. In this case, the control unit 12 may perform the imbalance suppressing operation when the absolute value of the SOC difference of the plurality of batteries is equal to or greater than the threshold. When causing the power conversion unit 40 to perform the imbalance suppressing operation, the control unit 12 puts the battery with the larger SOC into the discharging state or the charging stop state, and charges the battery with the smaller SOC. , the power conversion unit 40 is caused to perform power conversion. Then, the control unit 12 may end the imbalance suppressing operation when the absolute value of the SOC difference of the plurality of batteries becomes equal to or less than a certain value smaller than the threshold.

Also in the power supply systems of the first, second, fourth and other embodiments, relays 391, 392, 393, 394, 395, 396 and resistors 397, 398 similar to those of the third embodiment are provided. good too. For example, a relay 391 similar to that of the third embodiment is provided between the positive electrode of the first high voltage battery 71 and the position P3, and a relay 391 similar to that of the third embodiment is provided between the negative electrode of the first high voltage battery 71 and the position P1. relays 393, 395 and resistor 397 may be provided. Similarly, a relay 392 similar to that in the third embodiment is provided between the positive electrode of the second high voltage battery 72 and the position P4, and a relay 392 similar to that in the third embodiment is provided between the negative electrode of the second high voltage battery 72 and the position P2. Similar relays 394, 396 and resistor 398 may be provided. In this example, the power supply system 3 supplies power from both the first high voltage battery 71 and the second high voltage battery 72 to the power paths 81 and 82 by turning on and off relays 391, 392, 393, 394, 395 and 396. a first state that allows power to be supplied from the first high voltage battery 71 to the power paths 81 and 82, and cuts off the power supply from the second high voltage battery 72 to the power paths 81 and 82. A second state and a third state in which power supply from the second high voltage battery 72 to the power paths 81 and 82 is allowed and power supply from the first high voltage battery 71 to the power paths 81 and 82 is cut off. , can be switched.

It should be noted that the embodiments disclosed this time should be considered as examples in all respects and not restrictive. The scope of the present invention is not limited to the embodiments disclosed this time, and includes all modifications within the scope indicated by the claims or within the scope equivalent to the claims. is intended.

3, 203, 303, 403: power supply system 10, 210, 310, 410: power supply control device 12: control unit 30, 230, 430: switching unit 31: relay (first relay)
32: Relay (second relay)
33: Relay (mechanical relay)
34: Relay (mechanical relay)
40, 240, 440: power conversion unit (DCDC converter)
81, 82: power paths 40, 240, 440: power conversion section 40A: first series section 40B: second series section 40Z: bridge circuit 41: semiconductor switch (first semiconductor switch)
42: semiconductor switch (second semiconductor switch, parallel switch)
43: semiconductor switch (third semiconductor switch, parallel switch)
44: semiconductor switch (fourth semiconductor switch)
46: Inductor 71: First high-voltage battery (battery, one battery)
72: Second high-voltage battery (battery, other battery)
442: Semiconductor switch (multipurpose switch)
443: Semiconductor switch (multipurpose switch)

Claims (6)

A power supply control device used in a power supply system in which a plurality of batteries can be connected at least in parallel,
a power conversion unit that performs power conversion between one of the plurality of batteries and the other battery;
a control unit that controls the power conversion unit;
has
A power supply control device, wherein the control unit causes the power conversion unit to perform a step-down operation or a step-up operation to adjust a voltage across the one battery and a voltage across the other battery. The power supply system has a switching unit that switches the connection state of the one battery and the other battery between series connection and parallel connection,
The power supply control device according to claim 1, wherein a predetermined part of said power conversion unit is also used as said switching unit. The power conversion unit includes a plurality of semiconductor switches and an inductor, and has a DCDC converter that performs voltage conversion by turning on and off the plurality of semiconductor switches,
The switching unit has a mechanical relay,
the plurality of semiconductor switches include a parallel switch connected in parallel to the mechanical relay;
the parallel switch and the mechanical relay are provided in parallel in a path between the negative electrode of the one battery and the positive electrode of the other battery;
3. The power supply control device according to claim 2, wherein when the mechanical relay is in an ON state, electrical continuity is established between the negative electrode of the one battery and the positive electrode of the other battery. The DCDC converter comprises a bridge circuit,
The bridge circuit is
a first series section in which a first semiconductor switch and a second semiconductor switch among the plurality of semiconductor switches are connected in series;
a second series section in which a third semiconductor switch and a fourth semiconductor switch among the plurality of semiconductor switches are connected in series;
the inductor;
with
The first series unit is connected in parallel to the one battery,
one end of the first semiconductor switch is electrically connected to the positive electrode of the one battery;
one end of the second semiconductor switch is electrically connected to the negative electrode of the one battery;
the second series unit is connected in parallel to the other battery;
one end of the third semiconductor switch is electrically connected to the positive electrode of the other battery;
one end of the fourth semiconductor switch is electrically connected to the negative electrode of the other battery;
one end of the inductor is electrically connected to a portion between the first semiconductor switch and the second semiconductor switch in the first series section;
the other end of the inductor is electrically connected to a portion between the third semiconductor switch and the fourth semiconductor switch in the second series section;
one said mechanical relay is connected in parallel with said second semiconductor switch;
The other mechanical relay is connected in parallel with the third semiconductor switch,
The switching unit switches the one battery through the one mechanical relay, the other mechanical relay, and the inductor by switching the one mechanical relay and the other mechanical relay to the ON state. 4. The power supply control device according to claim 3, wherein the negative electrode and the positive electrode of the other battery are electrically connected to connect the one battery and the other battery in series. The power conversion unit has a DCDC converter that includes a plurality of switches and an inductor, and performs voltage conversion by turning on and off the plurality of switches,
The plurality of switches includes a dual-purpose switch that is also used as the switching unit,
the dual-purpose switch is provided in a path between the negative electrode of the one battery and the positive electrode of the other battery;
The switching unit establishes electrical continuity between the negative electrode of the one battery and the positive electrode of the other battery by switching the dual-purpose switch to the ON state, thereby connecting the one battery and the other battery in series. Item 3. The power supply control device according to item 2. The switching unit includes a first relay interposed between the positive electrode of the one battery and the positive electrode of the other battery, and a second relay interposed between the negative electrode of the one battery and the negative electrode of the other battery. a relay;
By switching the first relay and the second relay to the ON state, the positive electrode of the one battery and the positive electrode of the other battery are short-circuited, and the negative electrode of the one battery and the negative electrode of the other battery are connected. The one battery and the other battery are connected in parallel by shorting,
The control unit provides an instruction to switch the first relay and the second relay to an OFF state when the power conversion unit performs the step-down operation or the step-up operation, and switches the positive electrode of the one battery to the other. The power supply control device according to any one of claims 2 to 5, wherein the short circuit of the positive electrode of the battery is released, and the short circuit of the negative electrode of the one battery and the negative electrode of the other battery is released.

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