JP5741385B2 - Battery charging system - Google Patents

Description

  The present invention relates to a battery charging system, and more particularly to a technique for supplying power from a battery to another battery.

  Conventionally, an electric vehicle and a hybrid vehicle that travel with a driving force from an electric motor are known. Generally, a battery for storing electric power to be supplied to an electric motor is mounted on an electric vehicle. The battery is charged with electric power supplied from the outside of the electric vehicle, for example, at a charging station or at home. As another charging method, Japanese Patent Laying-Open No. 2010-252520 discloses supplying electric power from the battery of one vehicle to the battery of the other vehicle.

JP 2010-252520 A

  However, JP 2010-252520 A assumes only the case where power is supplied from one battery to another battery, and does not assume the case where power is supplied from a plurality of batteries to another battery. .

  An object of the present invention is to suitably supply power from a plurality of batteries to another battery.

  In one embodiment, a battery charging system includes three or more bidirectional converters and a controller that controls the bidirectional converters. The control device preferentially supplies power to a specific battery from the battery with a large surplus power amount among the batteries connected to each of the plurality of bidirectional converters, and the surplus power amount of the battery that has discharged the power When the difference between the surplus power amount of another battery that is not being charged is equal to or less than the threshold value, power is supplied to a specific battery from a plurality of batteries that have the surplus power amount difference equal to or less than the threshold value. And controlling a plurality of bidirectional converters.

  According to this configuration, the remaining capacity of the battery serving as a power source can be leveled by preferentially discharging from a battery having a large power margin and then discharging from a plurality of batteries. Therefore, the difference in remaining capacity between batteries can be reduced. As a result, power can be suitably supplied from a plurality of batteries to other batteries.

  In another embodiment, the specific battery is the battery having the lowest remaining capacity among the batteries connected to each bidirectional converter.

According to this configuration, the remaining capacity of the battery that has consumed power can be preferentially recovered.
In yet another embodiment, the specific battery is the battery having the largest amount of power shortage among the batteries connected to each bidirectional converter.

According to this configuration, the remaining capacity of the battery that has consumed power can be preferentially recovered.
In yet another embodiment, the specific battery is a battery designated by the user from among the batteries connected to each bidirectional converter.

  According to this configuration, for example, the remaining capacity of the battery that the user desires to use can be preferentially recovered.

  In yet another embodiment, the charging system bypasses a plurality of bidirectional converters and directly connects a specific battery and a battery with the largest amount of surplus power, and the specific battery is identified from the battery with the largest amount of surplus power. A bypass circuit that supplies power to the battery is further provided. The control device has the same type of battery as that of the battery with the largest amount of surplus power, or the specification of a specific battery and the specification of the battery with the largest amount of surplus power are the same. In this case, the bypass circuit bypasses the plurality of bidirectional converters and directly connects the specific battery and the battery having the largest surplus power.

  According to this configuration, it is possible to charge a specific battery without losing power by the bidirectional converter.

It is a schematic block diagram which shows an electric vehicle. It is a figure which shows the electric system of an electric vehicle. It is a figure which shows a charging system. It is a figure which shows a charging system in case a commercial power source is available. It is a figure which shows the charging system when not using a commercial power source or when not using a commercial power source. It is a figure which shows the charging system in the case of supplying electric power from two batteries to one battery. It is a figure which shows the charging system of the state which bypassed the charger and connected two batteries directly. It is a flowchart which shows the process which a controller performs.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  Referring to FIG. 1, an electric motor 100, a battery 110, and an ECU (Electronic Control Unit) 120 are mounted on the electric vehicle. The electric vehicle travels by the driving force from the electric motor 100. That is, the electric motor 100 is mounted on an electric vehicle as a drive source.

  Electric motor 100 is a three-phase AC rotating electric machine including, for example, a U-phase coil, a V-phase coil, and a W-phase coil. The electric motor 100 is driven by electric power stored in the battery 110. The driving force of the electric motor 100 is transmitted to the driving wheel 130.

  At the time of regenerative braking of the electric vehicle, the electric motor 100 is driven by the drive wheels 130, and the electric motor 100 operates as a generator. As a result, the electric motor 100 operates as a regenerative brake that converts braking energy into electric power. The electric power generated by the electric motor 100 is stored in the battery 110.

  The battery 110 is an assembled battery configured by connecting a plurality of battery modules in which a plurality of battery cells are integrated in series. The voltage of the battery 110 is about 200V, for example. In addition to the electric motor 100, the battery 110 is charged with electric power supplied from a power source external to the electric vehicle.

  In the present embodiment, an electric vehicle is used as an example, but a hybrid vehicle equipped with an engine such as an internal combustion engine or an electric vehicle with a cruising range extending function may be used. A fuel cell vehicle equipped with a fuel cell may be used.

  ECU 120 controls electric motor 100, battery 110, and the like. In the present embodiment, the ECU 120 includes a remaining capacity (SOC: State Of Charge) [%] of the battery 110, an excess amount of power [kWh] of the battery 110, a shortage of the amount of power of the battery 110, a model of the battery 110, Various information such as the specifications of the battery 110 are calculated and stored.

  As an example, the remaining capacity of the battery 110 is calculated from a discharge power amount and a charge power amount of the battery 110 using a known method. The surplus power amount of the battery 110 corresponds to a value obtained by converting a difference or difference between a predetermined lower limit value of the remaining capacity of the battery 110 and the current remaining capacity into a power amount. The shortage of the electric energy of the battery 110 corresponds to a value obtained by converting the difference between the remaining capacity at the time of full charge and the current remaining capacity or the difference into the electric energy.

  In the present embodiment, communication device 140 is further mounted on the electric vehicle. The communication device 140 is used to communicate with a controller of a charging system, which will be described later, by an arbitrary communication method such as wireless or wired. The communication device 140 charges various information such as the voltage of the battery 110, the remaining capacity of the battery 110, the surplus power amount of the battery 110, the shortage of the power amount of the battery 110, the model of the battery 110, the specifications of the battery 110, and the like. Sent to the system controller.

  The electric system of the electric vehicle will be further described with reference to FIG. The electric vehicle is provided with a converter 200 and an inverter 210.

  Converter 200 includes a reactor, two npn transistors, and two diodes. One end of the reactor is connected to the positive electrode side of each battery, and the other end is connected to the connection point of the two npn transistors.

  Two npn-type transistors are connected in series. The npn type transistor is controlled by the ECU 120. A diode is connected between the collector and emitter of each npn transistor so that a current flows from the emitter side to the collector side.

  For example, an IGBT (Insulated Gate Bipolar Transistor) can be used as the npn transistor. Instead of the npn type transistor, a power switching element such as a power MOSFET (Metal Oxide Semiconductor Field-Effect Transistor) can be used.

  When the electric power discharged from the battery 110 is supplied to the electric motor 100, the voltage is boosted by the converter 200. Conversely, when the battery 110 is charged with the power generated by the electric motor 100, the voltage is stepped down by the converter 200.

  Inverter 210 includes a U-phase arm, a V-phase arm, and a W-phase arm. The U-phase arm, V-phase arm and W-phase arm are connected in parallel. Each of the U-phase arm, the V-phase arm, and the W-phase arm has two npn transistors connected in series. Between the collector and emitter of each npn-type transistor, a diode for passing a current from the emitter side to the collector side is connected. A connection point of each npn transistor in each arm is connected to an end portion different from a neutral point of each coil of electric motor 100.

  The inverter 210 converts a direct current supplied from the battery 110 into an alternating current and supplies the alternating current to the electric motor 100. Further, the inverter 210 converts the alternating current generated by the electric motor 100 into a direct current. Converter 200 and inverter 210 are controlled by ECU 120.

  A charging station for charging a battery will be described with reference to FIG. The charging station includes an AC / DC conversion circuit (bidirectional inverter) 402, chargers (bidirectional DC / DC converters) 410, 420, 430, a relay 440, a controller 450, and a switching circuit 460. A system 400 is provided. Although three chargers 410, 420, and 430 are shown in FIG. 3, four or more chargers may be provided. Further, the number and configuration of relays are not limited to those illustrated.

  As an example, the charging system 400 is provided with three ports 471, 472, and 473 so that batteries of three vehicles can be connected. In addition, you may comprise so that the battery of four or more vehicles can be connected. A battery that is not mounted on the vehicle may be connectable to the charging system 400. The charging system 400, particularly the chargers 410, 420, and 430 are controlled by the controller 450.

  The AC / DC conversion circuit 402 is composed of a single-phase bridge circuit. The AC / DC conversion circuit 402 converts AC power supplied from, for example, a facility (such as a power plant or substation) owned by an electric power company into DC power. The AC / DC conversion circuit 402 can also function as a boost chopper circuit that boosts the voltage by using a coil as a reactor.

  Chargers 410, 420, and 430 are connected between AC / DC conversion circuit 402 and the battery. Chargers 410, 420, and 430 output power for charging batteries 114, 116, and 118 as an example. The chargers 410, 420, and 430 are insulating chargers having an insulating transformer. It is not necessary to use an insulated charger. The batteries 114, 116, and 118 may be mounted on the vehicle or installed at a specific location.

  Further, in the present embodiment, chargers 410, 420, and 430 have functions as bidirectional DC / DC converters, and therefore, from batteries 114, 116, and 118 connected to respective chargers 410, 420, and 430. It is also possible to operate to discharge.

  Relay 440 is provided between AC / DC conversion circuit 402 and chargers 410, 420, and 430. When relay 440 is opened, commercial power supply 470 and chargers 410, 420, and 430 are disconnected.

  Switching circuit 460 includes relays 461, 462 and 463, and a bypass circuit 464. Relays 461, 462, and 463 are provided between chargers 410, 420, and 430 and batteries 114, 116, and 118, respectively. When relay 461 is opened, charging system 400 and battery 114 are disconnected. Similarly, charging system 400 and battery 116 are disconnected when relay 462 is opened, and charging system 400 and battery 118 are disconnected when relay 463 is opened.

  The bypass circuit 464 bypasses the plurality of chargers 410, 420, and 430, directly connects the batteries, and supplies power from the battery to another battery. The bypass circuit 464 includes relays 465 and 466. In the present embodiment, a combination of directly connected batteries can be selected by combining relays 461, 462, 463 and relays 465, 466.

  The controller 450 controls the AC / DC conversion circuit 402, the chargers 410, 420, and 430, the relays 440, 461, 462, and 463, and the bypass circuit 464. In addition, the controller 450 receives various information such as the battery voltage, the remaining battery capacity, the excess battery power, the battery power shortage, the battery model, and the battery specifications from the communication device mounted on each vehicle. Receive the information.

  For example, when the commercial power source 470 is available, the controller 450 closes the relay 440 and closes at least one of the relays 461, 462, and 463 as shown in FIG. Each charger 410, 420, 430 is controlled to charge at least one of 118.

  On the other hand, in a predetermined time zone such as a power outage or daytime, the controller 450 opens the relay 440, and the surplus battery among the batteries 114, 116, 118 connected to the chargers 410, 420, 430, respectively. Multiple chargers that preferentially supply power to the battery with the lowest remaining capacity, the battery with the least amount of power shortage, or the battery specified by the user from the battery with the highest power 410, 420 and 430 are controlled. Whether or not a power failure has occurred is determined by controller 450 based on, for example, whether or not the input voltage of AC / DC conversion circuit 402 is below a threshold value.

  Further, when the difference between the surplus power amount of the battery that has discharged power and the surplus power amount of the other battery that is not being charged is equal to or less than the threshold value, the controller 450 determines that the difference in surplus power amount is the threshold value. The plurality of chargers 410, 420, and 430 are controlled so that power is supplied from the following plurality of batteries to a specific battery to be charged. The threshold value is predetermined by the developer as a predetermined value equal to or greater than “0”. Therefore, when the surplus power amount of a battery that has discharged power is the same as the surplus power amount of another battery that is not being charged, power is supplied from a plurality of batteries with the same surplus power amount to a specific battery to be charged. The plurality of chargers 410, 420, and 430 are controlled so as to be supplied.

  As an example, it is assumed that the surplus electric energy of the battery 118 is the largest among the batteries 114, 116, and 118 connected to each of the plurality of chargers 410, 420, and 430. Further, it is assumed that the remaining capacity of the battery 114 is the lowest among the batteries 114, 116, and 118.

  In this case, as shown in FIG. 5, the relay 440 and the relay 462 are opened, and the relay 461 and the relay 463 are closed. As a result, the battery 118 and the battery 114 are connected via the charger 410 and the charger 430. In this state, charger 430 is controlled by controller 450 to discharge from battery 118. The charger 410 is controlled by the controller 450 so as to supply the electric power discharged from the battery 118 to the battery 114.

  Until the difference between the surplus power amount of the battery 118 and the surplus power amount of the battery 116 becomes equal to or less than the threshold (for example, the surplus power amount of the battery 118 becomes the same as the surplus power amount of the battery 116) ), The relay 462 is further closed as shown in FIG. As a result, the battery 116 is connected to the battery 114 via the charger 410 and the charger 420. In this state, charger 430 is controlled by controller 450 to discharge from battery 118, and charger 420 is controlled by controller 450 to discharge from battery 116. The charger 410 is controlled by the controller 450 so as to supply electric power discharged from the battery 118 and the battery 116 to the battery 114.

  For example, charging of the battery 114 is continued until the remaining capacity of the battery 114 reaches a predetermined target value, or until the remaining capacity of the battery 118 or the remaining capacity of the battery 116 reaches a predetermined lower limit value. The

  The remaining capacity of the batteries 116 and 118 serving as the power source can be leveled by preferentially discharging from the battery 118 having a large power margin and then discharging from the plurality of batteries 116 and 118. Therefore, the difference in remaining capacity between the battery 116 and the battery 118 can be reduced. By leveling the remaining capacities of the battery 116 and the battery 118, the power of the battery 116 and the battery 118 can be equally ensured even during a power failure. Therefore, both the vehicle equipped with battery 116 and the vehicle equipped with battery 118 can be maintained in a travelable state.

In addition, the controller 450 determines whether the type of the specific battery to be charged is the same as the type of the battery having the largest surplus power, or the specification of the specific battery to be charged and the surplus power. When the specification of the battery having the largest amount is the same, the battery having the largest surplus electric energy and the specific battery to be charged is bypassed by bypassing the chargers 410, 420, and 430 to the bypass circuit 464. And connect directly.

  As an example, it is assumed that the surplus power amount of the battery 118 is the largest, the remaining capacity of the battery 114 is the lowest, and the model of the battery 114 and the model of the battery 118 are the same. In this case, as shown in FIG. 7, the relay 440 and the relay 462 are opened, and the relay 461, the relay 463, the relay 465, and the relay 466 are closed. As a result, the battery 118 and the battery 114 are directly connected to bypass the charger 410 and the charger 430. Thereby, electric power is spontaneously supplied from the battery 118 to the battery 114. Therefore, battery 114 can be charged without causing power loss in chargers 410 and 430.

  With reference to FIG. 8, a process executed by controller 450 in the present embodiment will be described. The processing described below may be realized by software, may be realized by hardware, or may be realized by cooperation of software and hardware.

  In step (hereinafter, step is abbreviated as S) 100, it is determined whether a power failure has occurred or whether the current time is included in a preset time zone. When a power failure occurs or when the current time is included in a preset time zone (YES in S100), in S102, between AC / DC conversion circuit 402 and chargers 410, 420, 430 Relay 440 is opened.

  Thereafter, in S104, the battery to be charged is specified. As an example, when a user designates a battery by operating the controller 450, the designated battery is specified as a battery to be charged. When the user does not designate a battery, the battery having the lowest remaining battery capacity may be specified as the battery to be charged, and the battery having the largest power shortage may be specified as the battery to be charged.

  In S106, a battery that is preferentially discharged is specified. As an example, a battery having the largest surplus power is identified. Thereafter, in S108, it is determined whether the type of the specific battery to be charged is the same as the type of the battery that is preferentially discharged. You may determine whether the specification of the specific battery used as charge object and the specification of the battery discharged preferentially are the same.

  The type of the specific battery to be charged is the same as the type of the battery to be discharged preferentially, or the specification of the specific battery to be charged and the specification of the battery to be discharged preferentially are the same (YES in S108), in S110, a specific battery to be charged and a battery that is discharged preferentially are directly connected, bypassing the charger.

  Thereafter, when the voltage of the specific battery to be charged matches the preferentially discharged battery (YES in S112), the battery to be charged is specified again in S104, and the subsequent processing is repeated.

  If the type of the specific battery to be charged is different from the type of the battery that is discharged preferentially (NO in S108), the battery that is discharged preferentially and has the largest surplus electric power is determined in S114. The plurality of chargers 410, 420, and 430 are controlled so as to supply power to a specific battery to be charged.

  Thereafter, when the surplus power amount of the discharged battery and the surplus power amount of the other battery that is not being charged are equal to or less than the threshold value (YES in S116), the difference in surplus power amount is determined in S118. A plurality of chargers 410, 420, and 430 are controlled so that power is supplied to a specific battery from a plurality of batteries having a threshold value equal to or less than a threshold value.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  100 electric motor, 110, 114, 116, 118 battery, 140 communication device, 400 charging system, 402 AC / DC conversion circuit, 410, 420, 430 charger, 440, 461, 462, 463, 465, 466 relay, 450 Controller, 460 switching circuit, 464 bypass circuit, 470 commercial power supply, 471, 472, 473 ports.

Claims (5)

Three or more bidirectional converters;
A control device for controlling the plurality of bidirectional converters,
The controller is
Among the batteries connected to each of the plurality of bidirectional converters, power is supplied to a specific battery preferentially from a battery with a large surplus power,
When the difference between the surplus power amount of the battery that has discharged power and the surplus power amount of another battery that is not being charged is less than or equal to the threshold value, a plurality of batteries in which the difference in surplus power amount is less than or equal to the threshold value The battery charging system that controls the plurality of bidirectional converters to supply power to the specific battery.   The battery charging system according to claim 1, wherein the specific battery is a battery having a lowest remaining capacity among the batteries connected to each of the bidirectional converters.   2. The battery charging system according to claim 1, wherein the specific battery is a battery having a largest amount of power shortage among batteries connected to each of the bidirectional converters.   The battery charging system according to claim 1, wherein the specific battery is a battery designated by a user from among the batteries connected to each of the bidirectional converters. Three or more bidirectional converters;
A control device for controlling the plurality of bidirectional converters;
A bypass circuit that bypasses the plurality of bidirectional converters, directly connects a specific battery and a battery having the largest surplus power amount, and supplies power from the battery having the largest surplus power amount to the specific battery; With
The controller is
Determining whether the type or specification of the specific battery is the same as the type or specification of the battery with the largest excess power,
When the model of the specific battery is the same as the model of the battery having the largest surplus electric power, or the specifications of the specific battery and the specifications of the battery having the largest surplus electric power are the same In this case, the bypass circuit bypasses the plurality of bidirectional converters, and the specific battery and the battery having the largest surplus electric energy are directly connected,
When the type of the specific battery is different from the type of the battery having the largest surplus power, or when the specification of the specific battery is different from the specification of the battery having the largest surplus power, the plurality of of the connected battery to each of the bi-directional converter, to preferentially supply power to excess power amount is larger battery or et previous SL particular battery, and excess power amount of the battery was discharged power, charging the difference between in the other non excess power amount of the battery falls below the threshold value, the difference between the amount of power surplus is to supply power to a plurality of batteries or et previous SL particular battery below the threshold as such, that controls the plurality of bi-directional converter, a battery charging system.

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