JP2018196274A - Battery system - Google Patents

Abstract

To provide a battery system having an improved power supply efficiency in a battery system which includes a secondary battery and a fuel cell.SOLUTION: A battery system 1 includes: a drive motor 50; a secondary battery 20 which charges power to be supplied to the drive motor; and a fuel cell 30 which generates electric power to be charged to the secondary battery. The battery system 1 further includes: a power storage device 10 which charges power to be supplied to the drive motor; switchover units SW1-SW5 which can change between a first supply mode, in which power is supplied from the secondary battery to the drive motor without using the power charged in the power storage device, and a second supply mode in which power is supplied from the power storage device and the secondary battery to the drive motor in a state that the power storage device is connected in series with the secondary battery; and a control device 100 which controls the operation of the switchover units to thereby control the change of the mode of power supply to the drive motor. The power storage device is charged using power generated by the fuel cell.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a battery system.

  In recent years, a battery system including a secondary battery that stores electric power supplied to a load and a fuel cell that generates electric power charged to the secondary battery is used in various apparatuses. For example, as described in Patent Document 1, in an electric vehicle that travels by the output of a driving motor that is driven using electric power supplied from a secondary battery, the electric power generated by the fuel cell is There is an electric vehicle that allows the vehicle to continue running while charging a secondary battery and suppressing a remaining capacity (SOC: State Of Charge) of the secondary battery and depleting power. In such an electric vehicle, for example, the secondary battery is charged by an external power source, and the fuel cell is activated in accordance with a decrease in the remaining capacity of the secondary battery while the electric vehicle is traveling.

JP 2014-143851 A

  By the way, in said battery system mounted in an electric vehicle etc., it is thought desirable to improve the power supply efficiency which is the efficiency about supply of electric power. Specifically, in the battery system described above, the electric power stored in the secondary battery is supplied to the load via a power line connecting the secondary battery and the load. For example, in the supply of power from the secondary battery to the load, power loss occurs due to the internal resistance of the secondary battery and the electrical resistance of the power line. Such power loss can be a factor of reducing power supply efficiency in the battery system.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is a novel and capable of improving power supply efficiency in a battery system including a secondary battery and a fuel cell. It is to provide an improved battery system.

  In order to solve the above problems, according to an aspect of the present invention, a load, a secondary battery that stores electric power supplied to the load, and a fuel cell that generates electric power charged to the secondary battery, A power storage device that stores power supplied to the load, and a first power supply from the secondary battery to the load without using the power stored in the power storage device. A switching unit capable of switching between a supply mode and a second supply mode for supplying power from the power storage device and the secondary battery to the load in a state where the power storage device and the secondary battery are connected in series; And a control device that controls switching of a power supply mode to the load by controlling an operation of the switching unit, and the power storage device is charged using power generated by the fuel cell. Battery Stem is provided.

  In the first supply mode, the control device forms a closed circuit in which the secondary battery and the load are connected in series without including the power storage device, and in the second supply mode, the power storage device, A closed circuit in which a secondary battery and the load are connected in series may be formed.

  The battery system may be mounted on an electric vehicle, and the load may include a drive motor for the electric vehicle.

  The electric power stored in the secondary battery may be mainly used for driving the driving motor, and the electric power generated by the fuel cell may be mainly used for charging the secondary battery.

  The secondary battery may be connected to an external power source outside the electric vehicle, and may be charged using electric power supplied from the external power source.

  The control device switches the supply mode to the first supply mode when it is determined that the power demand value of the load is less than or equal to a reference value, and the power request value is determined to be greater than the reference value The supply mode may be switched to the second supply mode.

  The control device may determine whether or not the required power value is equal to or less than the reference value based on travel information that is information related to travel of the electric vehicle.

  The travel information may include an accelerator opening of the electric vehicle.

  The travel information may include a road gradient on which the electric vehicle travels.

  The control device may control switching of the supply mode according to a comparison result between a difference between a current value and a current request value in the load and a threshold value.

  The controller cancels an increase in power loss in the battery system caused by an increase in electrical resistance in the battery system that occurs when the supply mode is switched from the first supply mode to the second supply mode. Switching from the first supply mode to the second supply mode may be performed so that the power loss is reduced.

  The power storage device is connected to the fuel cell via a first power conversion device capable of converting a voltage, and the control device controls the operation of the first power conversion device and the fuel cell, thereby You may control supply to the said electrical storage apparatus of the electric power generated with a battery.

  The secondary battery is connected to the fuel cell via a second power conversion device capable of converting a voltage, and the control device controls the operations of the second power conversion device and the fuel cell, thereby You may control supply to the said secondary battery of the electric power generated with a fuel cell.

  The second power conversion device is capable of bi-directionally converting voltage, and the control device stores power in the secondary battery by controlling operations of the first power conversion device and the second power conversion device. The supplied power may be controlled to the power storage device.

  The power storage device may have a small internal resistance compared to the internal resistance of the secondary battery.

  The power storage device may be an electric double layer capacitor.

  As described above, according to the present invention, it is possible to improve power supply efficiency in a battery system including a secondary battery and a fuel cell.

It is a schematic diagram which shows the general electric circuit containing a battery and load. It is a schematic diagram which shows an example of schematic structure of the battery system which concerns on embodiment of this invention. It is a block diagram which shows an example of a function structure of the control apparatus which concerns on the same embodiment. It is a flowchart which shows an example of the flow of the process in the mode switching control which the control apparatus which concerns on the same embodiment performs. It is explanatory drawing which shows the flow of the electric power in 1st supply mode in the battery system which concerns on the same embodiment. It is explanatory drawing which shows the flow of the electric power in 2nd supply mode in the battery system which concerns on the same embodiment. It is a flowchart which shows the example different from FIG. 4 of the flow of the process in the mode switching control which the control apparatus which concerns on the same embodiment performs. It is a schematic diagram which shows an example of schematic structure of the battery system which concerns on a modification.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

<1. Power loss in electrical circuits>
First, prior to the description of the battery system 1 according to the embodiment of the present invention, the power loss caused by the electric resistance in the general electric circuit 9 will be described with reference to FIG.

  FIG. 1 is a schematic diagram showing a general electric circuit 9 including a battery 901 and a load 903.

  Battery 901 is connected to load 903 via power line 902. Here, when the internal resistance of the battery 901 is Rv, the electric resistance of the power line 902 is Ra, and the current is I, the potential difference Vr due to the voltage drop caused by the electric resistance in the electric circuit 9 is expressed by the following formula (1 ).

  Therefore, when the electromotive force of the battery 901 is V, the voltage VL applied to the load 903 is expressed by the following equation (2).

  Therefore, the power PL supplied to the load 903 is represented by the following formula (3).

In the formula (3), I × V corresponds to the output of the battery 901, and I ² × (Rv + Ra) corresponds to the power loss caused by the electric resistance in the electric circuit 9. Thus, the power PL supplied to the load 903 is smaller than the output of the battery 901 by the amount of power loss caused by the electrical resistance in the electrical circuit 9. Further, as shown in the equation (3), the power loss caused by the electric resistance in the electric circuit 9 is proportional to the square of the current I. Therefore, for example, when the current is increased with an increase in the required power value of the load 903, the power loss tends to increase significantly. Thereby, the power supply efficiency in the electric circuit 9 can be reduced.

<2. Battery system configuration>
Then, with reference to FIG.2 and FIG.3, the structure of the battery system 1 which concerns on embodiment of this invention is demonstrated. The battery system 1 is a battery system mounted on an electric vehicle. Hereinafter, the battery system 1 of the electric vehicle will be described as an example, but the battery system according to the present invention may be applied to another device different from the electric vehicle.

  FIG. 2 is a schematic diagram illustrating an example of a schematic configuration of the battery system 1 according to the present embodiment.

  For example, as shown in FIG. 2, the battery system 1 includes a power storage device 10, a secondary battery 20, a fuel cell 30, an inverter 40, a drive motor 50, a first power converter 60, Two power converters 70, an accelerator opening sensor 91, an acceleration sensor 92, a first battery sensor 93, a second battery sensor 94, and a control device 100 are provided. The inverter 40 and the drive motor 50 correspond to an example of a load according to the present invention. As described above, the load according to the present invention may include the drive motor 50 of the electric vehicle.

  The electric vehicle on which the battery system 1 is mounted can run using a drive motor 50 that is driven using electric power supplied from the secondary battery 20 as a drive source. In addition, the electric vehicle travels while charging the secondary battery 20 using the electric power generated by the fuel cell 30 and suppressing the remaining capacity SOC of the secondary battery 20 from being reduced and depleting the electric power. Can continue.

  The battery system 1 is mounted on, for example, a fuel cell range extender type electric vehicle. In the battery system 1 mounted on the fuel cell range extender type electric vehicle, specifically, the electric power stored in the secondary battery 20 is mainly used to drive the drive motor 50 and is generated by the fuel cell 30. Electric power is mainly used to charge the secondary battery 20. The electric power generated by the fuel cell 30 may be used for driving the drive motor 50. For example, the power generated by the fuel cell 30 may be used to drive the drive motor 50 in addition to the power stored in the secondary battery 20. The ratio of the frequency used for driving the driving motor 50 between the electric power stored in the secondary battery 20 and the electric power generated by the fuel cell 30 is not particularly limited. Further, in the battery system 1 mounted on the fuel cell range extender type electric vehicle, specifically, the secondary battery 20 can be connected to an external power source outside the electric vehicle, and the electric power supplied from the external power source. Can be used for charging.

  In the battery system 1, a switch for switching a power supply mode to the inverter 40 as a load is provided in a part of a power line connecting the devices. For example, the battery system 1 includes a first switch SW1, a second switch SW2, a third switch SW3, a fourth switch SW4, and a fifth switch SW5 as such switches. The first switch SW1, the second switch SW2, the third switch SW3, the fourth switch SW4, and the fifth switch SW5 correspond to an example of a switching unit according to the present invention. In the following description, it is assumed that when the switch is ON, the portion where the switch is provided is connected and can be energized, and when the switch is OFF, the portion where the switch is provided is blocked and not energized. To do.

  For example, the secondary battery 20 is connected to the inverter 40 via the first switch SW1 and the third switch SW3. Specifically, the first switch SW1 and the third switch SW3 are provided between the high voltage side of the secondary battery 20 and the high voltage side of the inverter 40. The secondary battery 20 is connected to the fuel cell 30 via the second power conversion device 70.

  For example, the low voltage side of the power storage device 10 is connected to the high voltage side of the secondary battery 20 via the second switch SW2. As described above, the power storage device 10 can be connected to the secondary battery 20 in series. The high voltage side of the power storage device 10 is connected to the high voltage side of the inverter 40 via the fourth switch SW4. In addition, the power storage device 10 is connected to the fuel cell 30 via the first power conversion device 60. Specifically, the low voltage side of the power storage device 10 is connected to the low voltage side of the first power converter 60 via the fifth switch SW5. The first power conversion device 60 is connected to the fuel cell 30 in parallel with the second power conversion device 70.

  When the first switch SW1, the third switch SW3, and the fifth switch SW5 are ON, and the second switch SW2 and the fourth switch SW4 are OFF, the secondary battery 20 without the power storage device 10 and the inverter 40 Is formed in a closed circuit. Thereby, the first supply mode for supplying power from the secondary battery 20 to the inverter 40 without using the power stored in the power storage device 10 is realized.

  On the other hand, when the first switch SW1, the third switch SW3, and the fifth switch SW5 are OFF and the second switch SW2 and the fourth switch SW4 are ON, the power storage device 10, the secondary battery 20, and the inverter 40 Is formed in a closed circuit. Thereby, the second supply mode for supplying power from the power storage device 10 and the secondary battery 20 to the inverter 40 in a state where the power storage device 10 and the secondary battery 20 are connected in series is realized.

  Thus, the first switch SW1, the second switch SW2, the third switch SW3, the fourth switch SW4, and the fifth switch SW5 can be switched between the first supply mode and the second supply mode.

  Each switch is driven by a drive device (not shown), and the operation of each switch can be controlled by controlling the operation of the drive device. The operations of the first switch SW1, the second switch SW2, and the fifth switch SW5 may be interlocked, and the operations of the third switch SW3 and the fourth switch SW4 may be interlocked. In this case, the operations of the drive device that drives the first switch SW1, the second switch SW2, and the fifth switch SW5 in conjunction with each other and the drive device that drives the third switch SW3 and the fourth switch SW4 in conjunction with each other are controlled. Thus, the operation of each switch can be controlled. The type of each switch is not particularly limited. For example, a semiconductor switch such as a transistor is preferably used as each switch. Note that a mechanical switch such as a relay may be used as each switch.

  The power storage device 10 is a device that can charge and discharge electric power. Specifically, power storage device 10 may have a small internal resistance compared to the internal resistance of secondary battery 20. For example, an electric double layer capacitor is used as the power storage device 10. Further, a hybrid capacitor such as a lithium ion capacitor may be used as the power storage device 10. A hybrid capacitor means a device in which one electrode is an electric double layer and the other electrode is a secondary battery that utilizes a redox reaction. Note that the type of the power storage device 10 is not limited to such an example. The type of power storage device 10 may be different from the type of secondary battery 20 or may be the same as the type of secondary battery 20.

  For example, the power storage device 10 may be configured to include a plurality of power storage device modules 11 that can charge and discharge power. Further, the plurality of power storage device modules 11 can be connected in series or in parallel. 2 illustrates an example in which two power storage device modules 11 are connected in parallel to each other, the number of power storage device modules 11 and connection paths are not limited to the example.

  The power storage device 10 stores power supplied to the load. Specifically, the power storage device 10 stores power that is a power source of the drive motor 50 and is supplied to the inverter 40. The power storage device 10 is additionally used as a power supply source to the inverter 40 in the second supply mode. The electromotive force of the power storage device 10 is smaller than, for example, the electromotive force of the secondary battery 20. Specifically, the electromotive force of the power storage device 10 can be about 10% to 20% of the electromotive force of the secondary battery 20. Note that the electromotive force of power storage device 10 may be approximately the same as that of secondary battery 20 or may be large.

  Note that the electric power stored in the power storage device 10 may be supplied to auxiliary machines that are components such as various electric components, electronic devices, air conditioners in the vehicle interior, and display devices provided in the electric vehicle.

  The secondary battery 20 is a battery that can charge and discharge electric power. As the secondary battery 20, for example, a lithium ion battery, a lithium ion polymer battery, a nickel metal hydride battery, a nickel cadmium battery, or a lead storage battery is used. Note that the type of the secondary battery 20 is not limited to such an example.

  For example, the secondary battery 20 may be configured to include a plurality of secondary battery modules 21 that can charge and discharge power. Each secondary battery module 21 may be configured to include a plurality of cells connected in series. The plurality of secondary battery modules 21 can be connected in series or in parallel. In addition, in FIG. 2, although the example in which the four secondary battery modules 21 connected in series are connected in parallel is shown, the number of secondary battery modules 21 and a connection path | route are not limited to the example which concerns.

  The secondary battery 20 stores the electric power supplied to the load. Specifically, the secondary battery 20 is a main power source of the driving motor 50 and stores the power supplied to the inverter 40. The secondary battery 20 is used as a power supply source to the inverter 40 regardless of the supply mode.

  In addition, the electric power stored in the secondary battery 20 may be supplied to an auxiliary device provided in the electric vehicle. Further, the secondary battery 20 can be connected to an external power source outside the electric vehicle via a charging circuit and a connector (not shown), and is charged using power supplied from the external power source in a state of being connected to the external power source. obtain.

  The fuel cell 30 is a battery that can generate electricity by reacting hydrogen gas and oxygen gas. The fuel cell 30 is connected to a hydrogen tank (not shown), and the hydrogen tank is filled with, for example, high-pressure hydrogen supplied to the fuel cell 30. Hydrogen gas is supplied from the hydrogen tank to the fuel cell 30 by a motor pump or the like (not shown). The fuel cell 30 is supplied with air as oxygen gas by a compressor or the like (not shown). By controlling the supply amount of hydrogen gas and oxygen gas to the fuel cell 30, the output of the fuel cell 30 is controlled.

  The fuel cell 30 generates electric power that is charged to the secondary battery 20. Specifically, the fuel cell 30 generates low-voltage power as compared with the electromotive force of the secondary battery 20. The electric power generated by the fuel cell 30 is mainly used for charging the secondary battery 20. The electric power generated by the fuel cell 30 is also used for charging the power storage device 10.

  The inverter 40 performs bidirectional power conversion. The inverter 40 includes, for example, a three-phase bridge circuit.

  Specifically, the inverter 40 can convert supplied DC power into AC power and supply it to the drive motor 50. Further, the inverter 40 can convert AC power regenerated by the drive motor 50 into DC power and supply it to the secondary battery 20. The inverter 40 is provided with a switching element, and the conversion of power by the inverter 40 is controlled by controlling the operation of the switching element.

  The drive motor 50 can output power by being driven (powering drive) using supplied electric power. As the drive motor 50, for example, a three-phase AC motor is used. Further, the drive motor 50 may have a function (regeneration function) as a generator that is regeneratively driven when the electric vehicle is decelerated and generates power using the rotational energy of the wheels.

  Specifically, the drive motor 50 can output power for driving the drive wheels of the electric vehicle. The power output from the drive motor 50 is transmitted to, for example, a differential device (not shown), and is distributed and transmitted to the pair of left and right drive wheels by the differential device.

  The 1st power converter device 60 has a function as what is called a DCDC converter, and can convert a voltage. The first power converter 60 includes, for example, a so-called chopper circuit.

  Specifically, the first power conversion device 60 performs unidirectional voltage conversion from the fuel cell 30 side to the power storage device 10 side. The first power conversion device 60 can boost the power generated by the fuel cell 30 and supply it to the power storage device 10. The electric power generated by the fuel cell 30 is supplied to the power storage device 10 as DC power.

  The first power converter 60 is provided with a switching element, and the conversion of power by the first power converter 60 is controlled by controlling the operation of the switching element. In addition, the step-up ratio in the first power conversion device 60 is controlled by controlling the duty ratio in the switching operation of the switching element.

  The 2nd power converter device 70 has a function as what is called a DCDC converter, and can convert voltage. The second power conversion device 70 includes, for example, a so-called chopper circuit.

  Specifically, the second power conversion device 70 performs unidirectional voltage conversion from the fuel cell 30 side to the secondary battery 20 side. The second power conversion device 70 can boost the power generated by the fuel cell 30 and supply it to the secondary battery 20. The electric power generated by the fuel cell 30 is supplied to the secondary battery 20 as DC power.

  The second power conversion device 70 is provided with a switching element, and the conversion of power by the second power conversion device 70 is controlled by controlling the operation of the switching element. Note that the boost ratio in the second power converter 70 is controlled by controlling the duty ratio in the switching operation of the switching element.

  The accelerator opening sensor 91 detects the accelerator opening of the electric vehicle, which is the depression amount of the accelerator pedal, and outputs the detection result.

  The acceleration sensor 92 detects acceleration generated in the electric vehicle and outputs a detection result. For example, a sensor capable of detecting acceleration in three directions is used as the acceleration sensor 92.

  First battery sensor 93 detects information related to the state of power storage device 10 and outputs a detection result. For example, the first battery sensor 93 detects the open circuit voltage and the remaining capacity SOC of the power storage device 10 as such information.

  The second battery sensor 94 detects information related to the state of the secondary battery 20 and outputs a detection result. For example, the second battery sensor 94 detects the open circuit voltage and the remaining capacity SOC of the secondary battery 20 as such information.

  The control device 100 includes a CPU (Central Processing Unit) that is an arithmetic processing unit, a ROM (Read Only Memory) that is a storage element that stores programs used by the CPU, operational parameters, and the like, and parameters that change as appropriate during execution of the CPU. It is composed of a RAM (Random Access Memory) or the like that is a storage element for temporary storage.

  FIG. 3 is a block diagram illustrating an example of a functional configuration of the control device 100 according to the present embodiment. For example, as illustrated in FIG. 3, the control device 100 includes a determination unit 110 and a control unit 130.

  The determination unit 110 executes each determination and outputs a determination result to the control unit 130.

  The control unit 130 controls the operation of each device by outputting an operation command to each device provided in the battery system 1. For example, as illustrated in FIG. 3, the control unit 130 includes a supply mode control unit 131, a drive control unit 132, and a charge control unit 133.

  The supply mode control unit 131 controls the operation of the first switch SW1, the second switch SW2, the third switch SW3, the fourth switch SW4, and the fifth switch SW5 according to the determination result by the determination unit 110, thereby reducing the load. The switching of the power supply mode to the inverter 40 is controlled. As described above, the mode switching control for controlling the switching of the power supply mode to the inverter 40 is executed by the determination unit 110 and the supply mode control unit 131.

  The drive control unit 132 controls the operation of the inverter 40 to execute drive control for controlling the power supplied to the drive motor 50.

  The charge control unit 133 controls the operation of the first power conversion device 60, the second power conversion device 70, and the fuel cell 30, thereby performing charge control that controls the supply of power to the power storage device 10 and the secondary battery 20. Run.

  Further, the control device 100 receives information output from each device. Communication between the control device 100 and each device is realized by using, for example, CAN (Controller Area Network) communication. For example, the control device 100 receives information output from the accelerator opening sensor 91, the acceleration sensor 92, the first battery sensor 93, and the second battery sensor 94. The functions of the control device 100 according to the present embodiment may be divided by a plurality of control devices. In that case, the plurality of control devices may be connected to each other via a communication bus such as CAN.

<3. Battery system operation>
Then, with reference to FIGS. 4-7, operation | movement of the battery system 1 which concerns on embodiment of this invention is demonstrated.

  FIG. 4 is a flowchart illustrating an example of a process flow in the mode switching control executed by the control device 100 according to the present embodiment. FIG. 5 is an explanatory diagram showing the flow of power during the first supply mode in the battery system 1 according to the present embodiment. FIG. 6 is an explanatory diagram showing the flow of power during the second supply mode in the battery system 1 according to the present embodiment. FIG. 7 is a flowchart showing an example different from FIG. 4 of the process flow in the mode switching control executed by the control device 100 according to the present embodiment.

[3-1. Mode switching control]
First, the mode switching control executed by the determination unit 110 and the supply mode control unit 131 will be described. In the mode switching control, the determination unit 110 and the supply mode control unit 131 repeat, for example, the control flow shown in FIG. 4 at a preset time interval.

  When the control flow shown in FIG. 4 is started, first, in step S501, the determination unit 110 determines whether or not the required power value of the drive motor 50 as a load is equal to or less than a reference value. When it is determined that the power requirement value of the drive motor 50 is equal to or less than the reference value (step S501 / YES), the process proceeds to step S503. On the other hand, if it is determined that the required power value of the drive motor 50 is greater than the reference value (step S501 / NO), the process proceeds to step S505. Specifically, the reference value is that the power loss caused by the electrical resistance in the battery system 1 when the power supply mode to the inverter 40 is the first supply mode, and the supply mode is the second supply mode. This value corresponds to a value that can be used to determine whether or not the required power value of the drive motor 50 is large enough to be larger than the case, and is a value that can be appropriately changed according to the design specifications of the battery system 1.

  For example, the determination unit 110 determines whether or not the power requirement value of the drive motor 50 is equal to or less than a reference value based on travel information that is information related to travel of the electric vehicle. The travel information is information serving as an index of the required power value of the drive motor 50, and may include, for example, the accelerator opening of the electric vehicle and the gradient of the road surface on which the electric vehicle travels.

  The determination unit 110 may determine that the required power value of the drive motor 50 is less than or equal to the reference value when the accelerator opening of the electric vehicle is less than or equal to the reference opening. Specifically, the reference opening is an accelerator opening that has a relatively high possibility that the required power value of the driving motor 50 becomes the reference value, and can be stored in advance in a storage element of the control device 100.

  Moreover, the determination part 110 may determine with the electric power requirement value of the drive motor 50 being below a reference value, when the gradient of the road surface on which an electric vehicle drive | works is below a reference | standard gradient. The determination unit 110 can calculate, for example, a pitch angle, which is an angle of inclination with respect to the pitch direction of the electric vehicle, as a road surface gradient based on acceleration generated in the electric vehicle. Specifically, the reference gradient is a gradient of a road surface in which the power demand value of the drive motor 50 is relatively likely to be a reference value, and can be stored in advance in a storage element of the control device 100.

  In the above description, the example in which the determination in step S501 is performed by comparing the accelerator opening with the reference opening or comparing the road surface gradient with the reference gradient has been described. However, the determination method in step S501 is limited to such an example. Not. For example, the determination unit 110 calculates whether or not the power requirement value of the driving motor 50 is equal to or less than the reference value by calculating the power requirement value of the driving motor 50 and comparing the calculation result with the reference value. You may judge. The calculation of the required power value of the drive motor 50 can be performed, for example, using a map that defines the relationship between various travel information and the required power value.

  In step S503, the supply mode control unit 131 switches the supply mode to the first supply mode. The first supply mode is a supply mode in which power is supplied from the secondary battery 20 to the inverter 40 as a load without using the power stored in the power storage device 10.

  For example, the supply mode control unit 131 switches to the first supply mode by turning on the first switch SW1, the third switch SW3, and the fifth switch SW5 and turning off the second switch SW2 and the fourth switch SW4. I do. Thereby, as shown in FIG. 5, a closed circuit is formed in which the secondary battery 20 and the inverter 40 are connected in series without including the power storage device 10. As described above, the supply mode control unit 131 forms a closed circuit in which the secondary battery 20 and the inverter 40 as a load are connected in series without including the power storage device 10 in the first supply mode. Specifically, in such a closed circuit, current flows in the order of the secondary battery 20, the first switch SW 1, the third switch SW 3, the inverter 40, and the secondary battery 20. Therefore, as indicated by the solid line arrow F <b> 19 in FIG. 5, power is supplied from the secondary battery 20 to the inverter 40 without using the power stored in the power storage device 10.

  In the first supply mode, the power storage device 10 is not used as a power supply source for the inverter 40, and the secondary battery 20 is used as a power supply source for the inverter 40. Therefore, the electromotive force of the power supply source to the inverter 40 corresponds to the electromotive force of the secondary battery 20.

  Further, in the first supply mode, when the second switch SW2 is turned off, the series connection between the power storage device 10 and the secondary battery 20 is interrupted. Thereby, it is suppressed that an electric current flows from the high voltage | pressure side of the secondary battery 20 to the 1st power converter device 60 side. Further, in the first supply mode, when the fourth switch SW4 is turned off, the series connection between the power storage device 10 and the inverter 40 is interrupted. Thereby, for example, when regenerative power generation is performed by the drive motor 50, current is prevented from flowing from the high voltage side of the inverter 40 to the power storage device 10 side. Note that a current flows from the high voltage side of the inverter 40 to the power storage device 10 side by providing a diode that regulates the direction of the current in one direction from the power storage device 10 side to the inverter 40 side instead of the fourth switch SW4. Is suppressed.

  In step S505, the supply mode control unit 131 switches the supply mode to the second supply mode. The second supply mode is a supply mode in which power is supplied from the power storage device 10 and the secondary battery 20 to the inverter 40 as a load in a state where the power storage device 10 and the secondary battery 20 are connected in series.

  For example, the supply mode control unit 131 switches to the second supply mode by turning off the first switch SW1, the third switch SW3, and the fifth switch SW5 and turning on the second switch SW2 and the fourth switch SW4. I do. Thereby, as shown in FIG. 6, a closed circuit is formed in which the power storage device 10, the secondary battery 20, and the inverter 40 are connected in series. Thus, supply mode control unit 131 forms a closed circuit in which power storage device 10, secondary battery 20, and inverter 40 as a load are connected in series in the second supply mode. Specifically, in such a closed circuit, a current flows through the secondary battery 20, the second switch SW 2, the power storage device 10, the fourth switch SW 4, the inverter 40, and the secondary battery 20 in this order. Therefore, as indicated by a solid arrow F29 in FIG. 6, power is supplied from the power storage device 10 and the secondary battery 20 to the inverter 40 in a state where the power storage device 10 and the secondary battery 20 are connected in series.

  In the second supply mode, the power storage device 10 and the secondary battery 20 connected in series are used as a power supply source to the inverter 40. Therefore, the electromotive force of the power supply source to inverter 40 corresponds to a value obtained by adding the electromotive force of power storage device 10 to the electromotive force of secondary battery 20. As described above, in the second supply mode, the electromotive force of the power supply source to the inverter 40 is compared with the first supply mode by additionally using the power storage device 10 as a power supply source to the inverter 40. And get bigger.

  In the second supply mode, when the fifth switch SW5 is turned off, the connection between the low voltage side of the power storage device 10 and the low voltage side of the first power conversion device 60 is cut off. Thereby, it is suppressed that an electric current flows from the high voltage | pressure side of the secondary battery 20 to the 1st power converter device 60 side.

  After step S503 or step S505, the control flow shown in FIG. 4 ends.

  Note that the control flow executed in the mode switching control is not limited to the example shown in FIG. For example, the determination unit 110 and the supply mode control unit 131 may execute the control flow shown in FIG. 7 in the mode switching control. Note that the control flow shown in FIG. 7 is an example of a control flow executed when the power supply mode to the inverter 40 is the first supply mode. For example, the control flow shown in FIG. 7 is repeated at a preset time interval when the supply mode is the first supply mode.

  When the control flow shown in FIG. 7 is started, first, in step S701, the determination unit 110 obtains a value obtained by subtracting the current value from the current request value in the drive motor 50 as a load from the threshold value. Determine whether it is larger. If it is determined that the value obtained by subtracting the current value from the current request value in the drive motor 50 is greater than the threshold value (step S701 / YES), the process proceeds to step S703. On the other hand, when it is determined that the value obtained by subtracting the current value from the current request value in the drive motor 50 is equal to or less than the threshold value (step S701 / NO), the control flow shown in FIG. The supply mode is maintained in the first supply mode.

  Here, when the current request value in the drive motor 50 is relatively large with respect to the current current value, it is predicted that the current supplied from the secondary battery 20 to the inverter 40 increases. Specifically, when the supply mode of the power to the inverter 40 is the first supply mode, the threshold value is the power loss caused by the electrical resistance in the battery system 1, and the supply mode is the second supply mode. This value corresponds to a value that can be used to determine whether or not the current supplied to the inverter 40 increases to an extent that the current is increased.

  Specifically, the determination unit 110 calculates a target torque of the driving motor 50 according to the traveling state of the vehicle, and calculates a current request value in the driving motor 50 according to the difference between the target torque and the actual torque. obtain. The determination unit 110 can calculate the target torque based on various parameters including the accelerator opening, for example. In addition, for example, the electric vehicle is equipped with a torque sensor that detects the torque that is actually output from the drive motor 50, and the control device 100 receives the detection result output from the torque sensor to acquire the actual torque. Can do.

  In step S703, the supply mode control unit 131 switches the supply mode from the first supply mode to the second supply mode.

  When the supply mode of power to the inverter 40 is the second supply mode, for example, the control device 100 has a value obtained by subtracting the current request value from the current current value in the drive motor 50 greater than the threshold value. Is determined, the supply mode is switched from the second supply mode to the first supply mode. On the other hand, when it is determined that the value obtained by subtracting the current request value from the current current value in drive motor 50 is equal to or less than the threshold value, control device 100 maintains the supply mode in the second supply mode.

  As described above, the control device 100 may control the switching of the supply mode according to the comparison result between the difference between the current value and the current request value in the driving motor 50 as a load and the threshold value.

  As described above, in the second supply mode, unlike the first supply mode, the power storage device 10 is additionally used as a power supply source to the inverter 40. Thereby, the electrical resistance in the battery system 1 is increased by switching the supply mode from the first supply mode to the second supply mode. Here, an increase in electrical resistance in the battery system 1 can be a factor that increases power loss in the battery system 1. On the other hand, in the second supply mode, the electromotive force of the power supply source to the inverter 40 is larger than that in the first supply mode, so that it is supplied from the secondary battery 20 to the inverter 40 as will be described later. An increase in current can be suppressed. Thereby, an increase in power loss caused by the electrical resistance in the battery system 1 can be suppressed.

  Therefore, the control device 100 in the mode switching control, specifically, in the battery system 1 due to an increase in electrical resistance in the battery system 1 caused by switching the supply mode from the first supply mode to the second supply mode. Switching from the first supply mode to the second supply mode is performed so that the increase in power loss is offset and the power loss is reduced.

  For example, the reference value in step S501 of the control flow shown in FIG. 4 or the threshold value in step S701 of the control flow shown in FIG. 7 is an increase in power loss in the battery system 1 due to an increase in electrical resistance in the battery system 1. Is appropriately set to a value at which switching from the first supply mode to the second supply mode can be performed so that the power loss is reduced.

[3-2. Drive control]
Next, drive control executed by the drive control unit 132 will be described.

  In the drive control, the drive control unit 132 controls the operation of the inverter 40 so that the power supplied to the drive motor 50 matches the required power value. More specifically, the drive control unit 132 determines the current supplied from the power supply source including at least the secondary battery 20 to the inverter 40 and the drive motor from the inverter 40 based on the current supply mode and the required power value. The current supplied to 50 is controlled. Here, in the second supply mode, as described above, the electromotive force of the power supply source to the inverter 40 is larger than that in the first supply mode. Therefore, if the power requirement values are the same, in the second supply mode, the current supplied to the inverter 40 can be reduced compared to the first supply mode. Therefore, in the second supply mode, although the required power value is larger than that in the first supply mode, it is possible to suppress an increase in the current supplied from the secondary battery 20 to the inverter 40.

[3-3. Charge control]
Next, charge control executed by the charge control unit 133 will be described.

  The charging control unit 133 controls the supply of the electric power generated by the fuel cell 30 to the power storage device 10 by controlling the operations of the first power conversion device 60 and the fuel cell 30 in the charging control. Specifically, the charging control unit 133 can charge the power generated by the fuel cell 30 by the power storage device 10 by causing the first power conversion device 60 to perform a switching operation while the fuel cell 30 is activated. The voltage is boosted to a sufficient voltage and supplied to the power storage device 10. Thereby, the power storage device 10 is charged using the electric power generated by the fuel cell 30.

  For example, the charging control unit 133 performs charging of the power storage device 10 using the power generated by the fuel cell 30 when the remaining capacity SOC of the power storage device 10 is lower than the first reference capacity. Specifically, the first reference capacity is a value that can determine whether or not the open circuit voltage of power storage device 10 is excessively low, and can be stored in advance in a storage element of control device 100.

  As described above, since the fifth switch SW5 is ON in the first supply mode, the power storage device 10 is connected to the first power conversion device 60 on the high voltage side and the low voltage side. Therefore, as indicated by the broken line arrow F <b> 11 in FIG. 5, the electric power generated by the fuel cell 30 can be supplied to the power storage device 10 via the first power conversion device 60 in the first supply mode. Therefore, the charging control unit 133 can execute the charging of the power storage device 10 using the power generated by the fuel cell 30 in the first supply mode.

  Further, the charging control unit 133 controls the supply of the power generated by the fuel cell 30 to the secondary battery 20 by controlling the operations of the second power conversion device 70 and the fuel cell 30 in the charging control. Specifically, the charge control unit 133 charges the power generated by the fuel cell 30 by the secondary battery 20 by causing the second power conversion device 70 to perform a switching operation while the fuel cell 30 is activated. The voltage is boosted to a possible voltage and supplied to the secondary battery 20. Thereby, the secondary battery 20 is charged using the electric power generated by the fuel cell 30.

  For example, when the remaining capacity SOC of the secondary battery 20 is lower than the second reference capacity, the charge control unit 133 performs charging of the secondary battery 20 using power generated by the fuel cell 30. Specifically, the second reference capacity is a value that can determine whether or not the open-circuit voltage of the secondary battery 20 is excessively low, and can be stored in advance in the storage element of the control device 100.

  The secondary battery 20 is connected to the second power converter 70 on the high voltage side and the low voltage side regardless of the supply mode. Therefore, as indicated by the broken line arrow F12 in FIG. 5 and the broken line arrow F22 in FIG. 6, in the first supply mode and the second supply mode, the electric power generated by the fuel cell 30 passes through the second power conversion device 70. The secondary battery 20 can be supplied. Therefore, the charging control unit 133 can execute the charging of the secondary battery 20 using the power generated by the fuel cell 30 in the first supply mode and the second supply mode.

  For example, when the remaining capacity SOC of the secondary battery 20 is lower than the second reference capacity, the charge control unit 133 causes the fuel cell 30 to generate power that can charge the secondary battery 20 relatively quickly. . Further, even when the remaining capacity SOC of the secondary battery 20 is equal to or higher than the second reference capacity, the charging control unit 133 is relatively low when the remaining capacity SOC of the power storage device 10 is lower than the first reference capacity. The fuel cell 30 may perform idling power generation for generating electric power. The electric power generated in the idling power generation can be used for charging the power storage device 10.

  Note that the charging control unit 133 may control the supply of the electric power regenerated by the drive motor 50 to the secondary battery 20 by controlling the operation of the inverter 40 when the electric vehicle is decelerated. At the time of deceleration of the electric vehicle, the driving motor 50 is not driven by powering, so the supply mode is switched to the first supply mode. Therefore, as illustrated in FIG. 5, a closed circuit is formed in which the secondary battery 20 and the inverter 40 are connected in series without including the power storage device 10. Thereby, the secondary battery 20 can be charged using the electric power regenerated by the drive motor 50.

<4. Effect of battery system>
Then, the effect of the battery system 1 which concerns on embodiment of this invention is demonstrated.

  In the battery system 1 according to the present embodiment, the first supply mode for supplying power from the secondary battery 20 to the inverter 40 as a load without using the power stored in the power storage device 10, the power storage device 10 and the secondary The second supply mode for supplying power from the power storage device 10 and the secondary battery 20 to the inverter 40 as a load can be switched while the battery 20 is connected in series. Thereby, the electromotive force of the power supply source to the inverter 40 can be increased by switching the supply mode from the first supply mode to the second supply mode. Therefore, it is possible to suppress an increase in the current supplied from the secondary battery 20 to the inverter 40 as the power requirement value of the drive motor 50 increases. Therefore, an increase in power loss caused by the electrical resistance in the battery system 1 can be suppressed. Therefore, it is possible to improve the power supply efficiency in the battery system 1 including the secondary battery 20 and the fuel cell 30.

  Furthermore, in the battery system 1 according to the present embodiment, the power storage device 10 is charged using electric power generated by the fuel cell 30. As a result, it is possible to suppress the remaining capacity SOC of the power storage device 10 from being reduced and the power from being depleted, so that the switching to the second supply mode can be continuously performed. Moreover, since the electric power generated in the idling power generation of the fuel cell 30 can be effectively used for charging the power storage device 10, the frequency with which the start and stop of the fuel cell 30 are repeated can be reduced. As a result, it is possible to suppress a decrease in energy efficiency due to repeated starting and stopping of the fuel cell 30.

  The battery system 1 can be mounted on a fuel cell range extender type electric vehicle. Thereby, it is possible to improve the power supply efficiency in the battery system 1 mounted on such an electric vehicle. Further, it is possible to suppress a decrease in energy efficiency due to repeated starting and stopping of the fuel cell 30 mounted on such an electric vehicle. In the battery system 1 mounted on the fuel cell range extender type electric vehicle, specifically, the electric power stored in the secondary battery 20 is mainly used to drive the drive motor 50 and is generated by the fuel cell 30. The electric power used is mainly used for charging the secondary battery 20. Alternatively, in the battery system 1 mounted on the fuel cell range extender type electric vehicle, specifically, the secondary battery 20 can be connected to an external power source outside the electric vehicle, and the electric power supplied from the external power source. Can be used for charging.

  Further, in the battery system 1, in the first supply mode, a closed circuit is formed in which the secondary battery 20 and the inverter 40 are connected in series without including the power storage device 10, and in the second supply mode, the power storage device 10 Then, a closed circuit in which the secondary battery 20 and the inverter 40 are connected in series can be formed. Accordingly, in the first supply mode, it is specifically realized that the secondary battery 20 is used as a power supply source to the inverter 40 without using the power storage device 10 as a power supply source to the inverter 40. . Further, in the second supply mode, it is specifically realized that the power storage device 10 and the secondary battery 20 connected in series are used as a power supply source to the inverter 40.

  In the battery system 1, when it is determined that the power requirement value of the drive motor 50 as a load is equal to or less than the reference value, the supply mode is switched to the first supply mode, and the power requirement value of the drive motor 50 is The supply mode can be switched to the second supply mode when it is determined that the reference value is greater than the reference value. Thereby, according to the electric power requirement value of the drive motor 50, a supply mode can be switched appropriately. Therefore, it is possible to appropriately suppress an increase in the current supplied from the secondary battery 20 to the inverter 40 as the power requirement value of the driving motor 50 increases. Therefore, an increase in power loss caused by the electrical resistance in the battery system 1 can be appropriately suppressed.

  Further, in the battery system 1, it can be determined whether or not the power requirement value of the driving motor 50 as a load is equal to or less than a reference value based on traveling information that is information related to traveling of the electric vehicle. Thereby, it is possible to appropriately determine whether or not the power requirement value of the drive motor 50 is equal to or less than the reference value.

  Further, in the battery system 1, the travel information includes the accelerator opening of the electric vehicle, and it can be determined based on the accelerator opening whether or not the required power value of the driving motor 50 as a load is equal to or less than a reference value. Thereby, it can be determined more appropriately according to the accelerator opening whether or not the required power value of the drive motor 50 is equal to or less than the reference value.

  In the battery system 1, the travel information includes a road surface gradient on which the electric vehicle travels, and it is determined based on the road surface gradient whether or not the required power value of the drive motor 50 as a load is equal to or less than a reference value. obtain. Thereby, it can be more appropriately determined according to the gradient of the road surface whether or not the required power value of the drive motor 50 is equal to or less than the reference value.

  In the battery system 1, the switching of the supply mode can be controlled according to the comparison result between the difference between the current value and the current request value in the driving motor 50 as a load and the threshold value. Here, when the current request value in the drive motor 50 is relatively large with respect to the current current value, it is predicted that the current supplied from the secondary battery 20 to the inverter 40 increases. Therefore, the current supplied from the secondary battery 20 to the inverter 40 is appropriately suppressed from being increased by switching the supply mode according to the comparison result between the difference between the current value and the current request value and the threshold value. can do. Therefore, an increase in power loss caused by the electrical resistance in the battery system 1 can be appropriately suppressed.

  Further, in the battery system 1, the increase in power loss in the battery system 1 due to the increase in electric resistance in the battery system 1 caused by switching the supply mode from the first supply mode to the second supply mode is offset and the power is increased. Switching from the first supply mode to the second supply mode can be performed so that the loss is reduced. Thereby, it is suppressed that the power loss in the battery system 1 increases due to the increase in electrical resistance in the battery system 1 caused by switching the supply mode from the first supply mode to the second supply mode. Therefore, an increase in power loss caused by the electric resistance in the battery system 1 can be more effectively suppressed.

  In the battery system 1, the operation of the first power conversion device 60 and the fuel cell 30 is controlled, so that the supply of power generated by the fuel cell 30 to the power storage device 10 can be controlled. Thereby, the electrical storage apparatus 10 can be charged appropriately. Therefore, it can suppress more effectively that the remaining capacity SOC of the electrical storage apparatus 10 falls and electric power is exhausted.

  In the battery system 1, the operation of the second power conversion device 70 and the fuel cell 30 is controlled, so that the supply of power generated by the fuel cell 30 to the secondary battery 20 can be controlled. Thereby, the secondary battery 20 can be appropriately charged. Therefore, it can suppress more effectively that the remaining capacity SOC of the secondary battery 20 falls, and electric power is exhausted.

  Further, in the battery system 1, the power storage device 10 can have an internal resistance that is smaller than the internal resistance of the secondary battery 20. Thereby, since the internal resistance of power storage device 10 can be made relatively small, an increase in power loss caused by the electrical resistance in battery system 1 can be more effectively suppressed in the second supply mode. .

  In the battery system 1, the power storage device 10 can be an electric double layer capacitor. Thereby, since the electrical storage apparatus 10 can be reduced in size, the freedom degree of the layout in the battery system 1 can be improved.

<5. Modification>
Then, with reference to FIG. 8, the battery system 5 which concerns on a modification is demonstrated.

  FIG. 8 is a schematic diagram illustrating an example of a schematic configuration of a battery system 5 according to a modification.

  In the battery system 5 which concerns on a modification, compared with the battery system 1 mentioned above, the structure of the 2nd power converter device 80 differs.

  The 2nd power converter device 80 concerning a modification has a function as what is called a DCDC converter, and can convert a voltage bidirectionally. The second power converter 80 includes, for example, a so-called chopper circuit.

  Specifically, the second power conversion device 80 performs bidirectional voltage conversion between the fuel cell 30 side and the secondary battery 20 side. The second power converter 80 can boost the power generated by the fuel cell 30 and supply it to the secondary battery 20. The electric power generated by the fuel cell 30 is supplied to the secondary battery 20 as DC power. Further, the second power conversion device 80 can step down the power stored in the secondary battery 20 and supply it to the first power conversion device 60. The electric power stored in the secondary battery 20 is supplied to the first power conversion device 60 as DC power. In that case, the first power conversion device 60 can boost the power supplied from the secondary battery 20 via the second power conversion device 80 and supply the boosted power to the power storage device 10.

  The second power converter 80 is provided with a switching element, and the conversion of power by the second power converter 80 is controlled by controlling the operation of the switching element. Specifically, the step-up ratio for voltage conversion from the fuel cell 30 side to the secondary battery 20 side in the second power converter 80 is controlled by controlling the duty ratio in the switching operation of the switching element. . Further, by controlling the duty ratio in the switching operation of the switching element, the step-down ratio for the voltage conversion from the secondary battery 20 side to the first power conversion device 60 side in the second power conversion device 80 is controlled. .

  In the modification, the charging control unit 133 controls the operation of the first power conversion device 60 and the second power conversion device 80 in the charging control, so that the power stored in the secondary battery 20 is supplied to the power storage device 10. The supply can be controlled. Specifically, the charging control unit 133 can charge the power stored in the secondary battery 20 by the power storage device 10 by causing the first power conversion device 60 and the second power conversion device 80 to perform a switching operation. The voltage is converted and supplied to the power storage device 10. Thereby, the power storage device 10 is charged using the power stored in the secondary battery 20.

  For example, the charge control unit 133 uses the power stored in the secondary battery 20 when the remaining capacity SOC of the power storage device 10 is lower than the first reference capacity and the fuel cell 30 is not activated. 10 charge is performed. In addition, the charging control unit 133 has such a power that the remaining capacity SOC of the power storage device 10 is lower than the first reference capacity, and the power generated by the fuel cell 30 can charge the power storage device 10 relatively quickly. If smaller, charging of the power storage device 10 using the power stored in the secondary battery 20 may be executed.

  As described above, since the fifth switch SW5 is ON in the first supply mode, the power storage device 10 is connected to the first power conversion device 60 on the high voltage side and the low voltage side. The secondary battery 20 is connected to the second power converter 80 on the high voltage side and the low voltage side regardless of the supply mode. The first power conversion device 60 is connected to the fuel cell 30 in parallel with the second power conversion device 80. Therefore, as indicated by the dashed arrow F51 in FIG. 7, in the first supply mode, the power stored in the secondary battery 20 is transferred to the power storage device 10 via the second power conversion device 80 and the first power conversion device 60. Can be supplied. Therefore, the charging control unit 133 can execute the charging of the power storage device 10 using the power stored in the secondary battery 20 in the first supply mode.

  In the battery system 5 according to the modification, the second power conversion device 80 can convert the voltage bidirectionally. Moreover, supply of the electric power stored in the secondary battery 20 to the power storage device 10 is controlled by controlling the operations of the first power conversion device 60 and the second power conversion device 80. As a result, even when the fuel cell 30 is not activated or when the power generated by the fuel cell 30 is smaller than the power that can charge the power storage device 10 relatively quickly, the power storage device 10 Can be charged properly. Therefore, since it can suppress more effectively that the remaining capacity SOC of the electrical storage apparatus 10 falls and electric power is exhausted, the effect which can be switched to 2nd supply mode continuously can be improved. it can.

<6. Conclusion>
As described above, according to the present embodiment, the first supply mode for supplying power from the secondary battery 20 to the load without using the power stored in the power storage device 10, the power storage device 10 and the secondary battery. The second supply mode for supplying power from the power storage device 10 and the secondary battery 20 to the load can be switched in a state in which the power supply device 20 is connected in series. Thereby, since the electromotive force of the power supply source to the load can be increased by switching the supply mode, it is possible to suppress an increase in the current supplied to the load as the power demand value of the load increases. be able to. Therefore, an increase in power loss caused by the electrical resistance in the battery system 1 can be suppressed. Therefore, it is possible to improve the power supply efficiency in the battery system 1 including the secondary battery 20 and the fuel cell 30.

  Furthermore, in the battery system 1 according to the present embodiment, the power storage device 10 is charged using electric power generated by the fuel cell 30. As a result, it is possible to suppress the remaining capacity SOC of the power storage device 10 from being reduced and the power from being depleted, so that the switching to the second supply mode can be continuously performed. Moreover, since the electric power generated in the idling power generation of the fuel cell 30 can be effectively used for charging the power storage device 10, the frequency with which the start and stop of the fuel cell 30 are repeated can be reduced. As a result, it is possible to suppress a decrease in energy efficiency due to repeated starting and stopping of the fuel cell 30.

  In the above, the power lines connecting the respective devices in the battery system 1 have been described with reference to the drawings. However, the connection paths of the power lines connecting the respective devices in the battery system 1 and the arrangement of the switches are related examples. It is not limited. Specifically, the connection path of the power line and the arrangement of the switches are configured such that the first supply mode for supplying power from the secondary battery 20 to the load without using the power stored in the power storage device 10, What is necessary is just to implement | achieve switchable to the 2nd supply mode which supplies electric power to the load from the electrical storage apparatus 10 and the secondary battery 20 in the state connected with the secondary battery 20 in series. For example, a switch may be further added to the battery system 1. Some switches may be omitted and may be replaced with other electric elements such as a diode.

  In the above description, the example in which the power storage device 10 can be charged using the power generated by the fuel cell 30 in the first supply mode has been described. However, the power storage device using the power generated by the fuel cell 30 is described. The 10 charging may be executable in the second supply mode. In that case, the supply mode control unit 131 connects the low voltage side of the power storage device 10 and the low voltage side of the first power converter 60 by turning on the fifth switch SW5 in the second supply mode. Here, in order to suppress a current from flowing from the high voltage side of the secondary battery 20 to the first power converter 60 side, for example, a transformer is provided between the first power converter 60 and the second power converter 70. Provided. As a result, the first power conversion device 60 and the second power conversion device 70 are insulated from each other, so that the fuel can be prevented from flowing from the high voltage side of the secondary battery 20 to the first power conversion device 60 side. The power storage device 10 can be charged using the power generated by the battery 30.

  Moreover, in the above, although the battery system 1 mounted in an electric vehicle was demonstrated as an example of the battery system which concerns on this invention, the battery system which concerns on this invention may be applied to other apparatuses different from an electric vehicle. For example, the battery system according to the present invention may be mounted on a railway or other transport machine equipped with a fuel cell.

  In the above description, the inverter 40 and the driving motor 50 are described as examples of the load according to the present invention, but the load according to the present invention is not limited to the example. The load which concerns on this invention should just be able to consume the electric power supplied, and may change suitably according to the apparatus in which a battery system is mounted.

  In the above description, the acceleration sensor 92 is used to calculate the road gradient. However, another sensor different from the acceleration sensor 92 may be used to calculate the road gradient. For example, a triaxial gyro sensor may be used as such a sensor. In that case, the acceleration sensor 92 may be omitted from the configuration of the battery system 1.

  The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can make various modifications or application examples within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1,5 Battery system 10 Electric power storage apparatus 11 Electric power storage apparatus module 20 Secondary battery 21 Secondary battery module 30 Fuel cell 40 Inverter 50 Driving motor 60 1st power converter 70, 80 2nd power converter 91 Accelerator opening degree sensor 92 Acceleration sensor 93 First battery sensor 94 Second battery sensor 100 Control device 110 Determination unit 130 Control unit 131 Supply mode control unit 132 Drive control unit 133 Charge control unit SW1 First switch SW2 Second switch SW3 Third switch SW4 Fourth switch SW5 5th switch

Claims (16)

Load,
A secondary battery for storing electric power supplied to the load;
A fuel cell for generating electric power charged in the secondary battery;
A battery system comprising:
A power storage device that stores power supplied to the load;
The first supply mode for supplying power from the secondary battery to the load without using the power stored in the power storage device, and the power storage device and the secondary battery are connected in series. A switching unit capable of switching between a power storage device and a second supply mode for supplying power from the secondary battery to the load;
A control device that controls switching of a power supply mode to the load by controlling the operation of the switching unit;
Further comprising
The power storage device is charged using electric power generated by the fuel cell.
Battery system. In the first supply mode, the control device forms a closed circuit in which the secondary battery and the load are connected in series without including the power storage device, and in the second supply mode, the power storage device, Forming a closed circuit in which a secondary battery and the load are connected in series;
The battery system according to claim 1. The battery system is mounted on an electric vehicle,
The load includes a drive motor for the electric vehicle.
The battery system according to claim 1 or 2. The power stored in the secondary battery is mainly used for driving the drive motor,
The power generated by the fuel cell is mainly used for charging the secondary battery.
The battery system according to claim 3. The secondary battery can be connected to an external power source outside the electric vehicle, and is charged using electric power supplied from the external power source.
The battery system according to claim 3 or 4. The control device switches the supply mode to the first supply mode when it is determined that the power demand value of the load is less than or equal to a reference value, and the power request value is determined to be greater than the reference value Switching the supply mode to the second supply mode,
The battery system according to any one of claims 3 to 5. The control device determines whether or not the power requirement value is equal to or less than the reference value based on travel information that is information related to travel of the electric vehicle.
The battery system according to claim 6. The travel information includes an accelerator opening of the electric vehicle,
The battery system according to claim 7. The travel information includes a slope of a road surface on which the electric vehicle travels.
The battery system according to claim 7 or 8. The control device controls switching of the supply mode according to a comparison result between a difference between a current value and a current request value in the load and a current request value,
The battery system according to any one of claims 1 to 9. The controller cancels an increase in power loss in the battery system caused by an increase in electrical resistance in the battery system that occurs when the supply mode is switched from the first supply mode to the second supply mode. Performing a switch from the first supply mode to the second supply mode so that the power loss is reduced;
The battery system according to any one of claims 1 to 10. The power storage device is connected to the fuel cell via a first power conversion device capable of converting a voltage,
The control device controls supply of the electric power generated by the fuel cell to the power storage device by controlling operations of the first power conversion device and the fuel cell.
The battery system according to any one of claims 1 to 11. The secondary battery is connected to the fuel cell via a second power conversion device capable of converting voltage,
The control device controls supply of the electric power generated by the fuel cell to the secondary battery by controlling operations of the second power conversion device and the fuel cell.
The battery system according to claim 12. The second power converter is capable of converting a voltage bidirectionally,
The control device controls the supply of power stored in the secondary battery to the power storage device by controlling operations of the first power conversion device and the second power conversion device.
The battery system according to claim 13. The power storage device has a small internal resistance compared to the internal resistance of the secondary battery.
The battery system according to any one of claims 1 to 14. The power storage device is an electric double layer capacitor,
The battery system according to claim 15.

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