JP2017139843A - Power storage system and control method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power storage system which can achieve both of a high energy density and a high output density more reliably.SOLUTION: A method for controlling a power storage system 10 comprises the steps of discharging or charging a first power storage device 11 in response to a power feeding request and a power-accumulating request, and discharging or charging a second power storage device 12 according to a remaining capacity of the first power storage device 11 in the power storage system 10 in which the first power storage device 11 and the second power storage device 12 are connected in parallel with each other, the first power storage device 11 is higher, in output density, than the second power storage device 12, and the second power storage device 12 is higher, in energy density, than the first power storage device 11.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a high energy density power storage device, a power storage system including a high power density power storage device, and a control method thereof.

  Conventionally, for example, a power storage system disclosed in Patent Document 1 is known as a power storage system that achieves both high energy density and high power density. The power storage system includes a power converter, a secondary battery, a capacitor, and a control device. The load side terminal of the power converter is connected to the load. Moreover, the power supply side terminal of the power converter is connected to the secondary battery and is connected to the capacitor in parallel with the secondary battery via the DC / DC converter. The DC / DC converter is controlled by the control device so that the capacitor is charged and discharged with priority over the secondary battery.

JP, 2006-001936, A

  In the electric power storage system of Patent Literature 1, the remaining capacity of the capacitor is not adjusted, and the capacitor is controlled to be charged and discharged with priority over the secondary battery. For this reason, there is a possibility that the capacitor cannot be discharged when the remaining capacity of the capacitor is small, or the capacitor cannot be charged when the remaining capacity of the capacitor is large. Therefore, this power storage system has room for improvement in terms of both high energy density and high power density.

  The present invention has been made to solve such problems, and an object of the present invention is to provide an electric power storage system and a control method therefor capable of achieving both high energy density and high output density more reliably. .

  According to a control method of an electric power storage system according to an aspect of the present invention, a first power storage device and a second power storage device are connected in parallel to each other, and an output density of the first power storage device is greater than an output density of the second power storage device. And in the power storage system in which the energy density of the second power storage device is higher than the energy density of the first power storage device, the first power storage device is discharged or charged in response to a power supply request and a power storage request. The second power storage device is discharged or charged according to the remaining capacity of the first power storage device.

  In this power storage system control method, when there is no power supply request and no power storage request, and the remaining capacity of the first power storage device is not within a predetermined range, the remaining capacity of the first power storage device is at or near a predetermined range. As described above, the second power storage device may be discharged or charged.

  In the control method of the power storage system, when there is a power supply request and the remaining capacity of the first power storage device is not within a predetermined range, the discharge power or charge power of the first power storage device and the second power storage device The first power storage device may be discharged or charged and the second power storage device may be discharged or charged so that the total power of the discharge power or the charge power of the power becomes the power required for the power supply.

  Here, in the control method of the power storage system, when there is a power supply request and the remaining capacity of the first power storage device is greater than the predetermined range, the remaining capacity of the first power storage device is the predetermined range or the The first power storage device may be discharged and the second power storage device may be charged so as to approach. Further, in the control method of the power storage system, when there is a power supply request and the remaining capacity of the first power storage device is less than the predetermined range, the remaining capacity of the first power storage device is at or near the predetermined range. Alternatively, the first power storage device may be discharged or charged and the second power storage device may be discharged so as to suppress the remaining capacity of the first power storage device from becoming smaller than the predetermined range. Good.

  Further, in the control method of the power storage system, when there is a demand for power storage, if the remaining capacity of the first power storage device is not within a predetermined range, the discharge power or charge power of the first power storage device and the second power storage device The first power storage device may be discharged or charged and the second power storage device may be discharged or charged so that the total power of the discharge power or the charge power becomes the power required for the power storage.

  Here, in the control method of the power storage system, when there is a power storage request, if the remaining capacity of the first power storage device is less than the predetermined range, the remaining capacity of the first power storage device is the predetermined range or the same. The first power storage device may be charged and the second power storage device may be discharged so as to approach. Further, in the control method of the power storage system, when there is a power storage request and the remaining capacity of the first power storage device is greater than the predetermined range, the remaining capacity of the first power storage device is at or near the predetermined range. Alternatively, the first power storage device may be discharged or charged and the second power storage device may be charged so that the remaining capacity of the first power storage device is further suppressed from exceeding the predetermined range. Good.

  In addition, the power storage system used in the method for controlling the power storage system includes an electric circuit capable of connecting and disconnecting the first power storage device and the second power storage device without using a charge / discharge control circuit, and the first power storage system. When charging the discharge power of the device to the second power storage device, or when charging the discharge power of the second power storage device to the first power storage device, the first power storage device and the second power storage device are connected. May be.

  A power storage system according to another aspect of the present invention controls a first power storage device, a second power storage device connected in parallel to the first power storage device, the first power storage device, and the second power storage device. And an output density of the first power storage device is higher than an output density of the second power storage device, and an energy density of the second power storage device is higher than an energy density of the first power storage device. The control device is configured to discharge or charge the first power storage device according to a power supply request and a power storage request, and to discharge or charge the second power storage device according to a remaining capacity of the first power storage device. ing.

  The present invention has the above-described configuration, and provides an effect that it is possible to provide an electric power storage system and a control method thereof that can more reliably achieve both high energy density and high output density.

  The above object, other objects, features, and advantages of the present invention will become apparent from the following detailed description of preferred embodiments with reference to the accompanying drawings.

It is a functional block diagram which shows the structure of the electric power storage system which concerns on Embodiment 1 of this invention. It is a flowchart which shows an example of the control method of the electric power storage system of FIG. It is a flowchart which shows an example of the control method of the electric power storage system of FIG. It is a flowchart which shows an example of the control method of the electric power storage system of FIG. It is a figure which shows schematically the profile of the electric power feeding and stored electric power with respect to the electric power storage system of FIG. FIG. 6A is a diagram schematically showing charge / discharge power of each power storage device in response to a power supply request for high power output, and FIG. 6B schematically shows charge / discharge power of each power storage device in response to a power supply request for low power output. FIG. 6C is a diagram schematically showing charge / discharge power of each power storage device in response to a power storage request with a high power input, and FIG. 6D shows charge / discharge power of each power storage device in response to a power storage request with a low power input. It is a figure shown roughly. It is a functional block diagram which shows the structure of the electric power storage system which concerns on Embodiment 2 of this invention.

  Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. In the following description, the same or corresponding elements are denoted by the same reference symbols throughout the drawings, and redundant description thereof is omitted.

(Embodiment 1)
The configuration of the power storage system 10 according to the first embodiment will be described with reference to FIG. The power storage system 10 includes a first power storage device 11, a second power storage device 12, and a control device 13. The first power storage device 11 and the second power storage device 12 are connected in parallel to each other. The power storage system 10 is connected to an external device 31 via a DC / AC inverter 30. The external device 31 consumes power output from the power storage system 10 or supplies power to the power storage system 10.

  The DC / AC inverter (power converter) 30 has a load side terminal connected to an external device 31. The DC / AC inverter 30 converts the DC power input to the power supply side terminal into AC power, and outputs the AC power from the load side terminal. Further, the DC / AC inverter 30 converts AC power input to the load side terminal into DC power, and outputs the DC power from the power source side terminal. The first power storage device 11 and the second power storage device 12 are connected in parallel to each other on the power supply side terminal. The first power storage device 11 is connected to the power supply side terminal of the DC / AC inverter 30 via the DC / DC converter 15.

  Specifically, the second power storage device 12 is connected to the power supply side terminal of the DC / AC inverter 30 via the DC link 14 configured by a pair of wires, and the first power storage device 11 is connected to the DC link 14 via the DC / AC inverter 30. It is connected via a DC converter 15.

  The first power storage device 11 is a high output power storage device having a higher output density than the second power storage device 12. Examples of the first power storage device 11 include a capacitor and a secondary battery. Examples of the capacitor include a lithium ion capacitor and an electric double layer capacitor. In the case where the first power storage device 11 is a capacitor having general characteristics, the first power storage device 11 stores the charge directly (without going through a reaction) and directly releases the stored charge.

  The DC / DC converter 15 changes the current of the first power storage device 11 by changing the conduction rate. The DC / DC converter 15 may have a step-up function or a step-down function that can change the voltage. A DC reactor 16 (DCL) is connected in series with the DC / DC converter 15 between the connection point of the first power storage device 11 and the DC / DC converter 15. The DC reactor 16 smoothes the current output from the DC / DC converter 15 or input to the DC / DC converter 15.

  The second power storage device 12 is a large-capacity power storage device having a higher energy density than the first power storage device 11. As the 2nd electrical storage apparatus 12, a lithium ion battery, a nickel metal hydride battery, and a lead acid battery are used, for example. In this case, the second power storage device 12 accumulates the charge through a chemical reaction or a physical reaction, and releases the accumulated charge through a reverse reaction.

  Control device 13 controls charging / discharging of first power storage device 11 and second power storage device 12 by DC / DC converter 15. For example, the control device 13 discharges or charges the first power storage device 11 according to the power supply request and the power storage request. Further, the second power storage device 12 is discharged or charged according to the remaining capacity (State Of Charge) of the first power storage device 11 (hereinafter referred to as “first SOC”). The control device 13 includes an arithmetic processing unit and a storage unit that stores a control program. An MPU and a CPU are exemplified as the arithmetic processing unit, and a memory is exemplified as the storage unit. The control device 13 may be configured by a single control device 13 that performs centralized control, or may be configured by a plurality of control devices 13 that perform distributed control in cooperation with each other.

  Next, a control method of the power storage system 10 will be specifically described with reference to FIGS. The control method shown in FIGS. 2 to 4 is controlled by the control device 13. The control device 13 is connected to an external controller, and acquires a power supply request or a power storage request of an external device 31 connected to the power storage system 10 from an external controller (not shown).

  First, the control device 13 monitors whether or not a power supply request or a power storage request for the external device 31 is input from the external controller (step S1). When the power supply request and the power storage request are not input to the control device 13 (step S1: NO), the control device 13 determines whether or not the first SOC is within a predetermined range (step S2). This first SOC is obtained by measuring voltage or current. That is, when the first power storage device 11 is a capacitor having a general characteristic, the first SOC is proportional to the square of the voltage of the first power storage device 11, and thus the first SOC is measured by measuring the voltage of the first power storage device 11. Is obtained. Further, the current value of charging / discharging of the first power storage device 11 is measured, and the amount of charge input / output to / from the first power storage device 11 is obtained by integrating the current value, and the first SOC is obtained from this charge amount.

  The predetermined range is determined in advance based on, for example, a charge / discharge profile of the power storage system 10. For example, in the charge / discharge profile of the power storage system 10 shown in FIG. 5, three discharges (time d) are performed from the power storage system 10, and one charge (time c) is performed in the power storage system 10. ing. In each of these discharges, 10% of the first SOC is output from the power storage system 10, and in charging, 30% of the first SOC is supplied to the power storage system 10. For this reason, the predetermined range can be set to 30% or more and 70% or less of the first SOC.

  Note that a power supply request is input to the control device 13 at time d, and a power storage request is input to the control device 13 at time c. During this time i, there is no power supply request or power storage request, and it is determined here whether or not the first SOC is within a predetermined range.

  If the first SOC is not within the predetermined range (step S2: NO), the second power storage device 12 is discharged or charged so that the first SOC is within the predetermined range or close to the predetermined range (step S3). That is, when the first SOC is less than the predetermined range, the control device 13 outputs a discharge command for the second power storage device 12 to the DC / DC so that the power output from the second power storage device 12 is stored in the first power storage device 11. Output to the converter 15. On the other hand, when the first SOC is greater than the predetermined range, the control device 13 outputs a charge command for the second power storage device 12 to the DC so that the power output from the first power storage device 11 is stored in the second power storage device 12. / Output to DC converter 15. As a result, the first SOC falls within a predetermined range, and the first power storage device 11 can be discharged and charged in response to a power supply request or a power storage request.

  On the other hand, when the first SOC is within the predetermined range (step S2: YES), even if there is a power supply request or a power storage request, charging and discharging can be performed from the first power storage device 11 in response to this request. For this reason, it is not necessary to discharge or charge the 2nd electrical storage apparatus 12 so that 1st SOC may be in a predetermined range or it.

  Moreover, in the process of step S1, when a power supply request or a power storage request is input to the control device 13 (step S1: YES), the control device 13 determines whether or not the first SOC is within a predetermined range ( Step S4). If the first SOC is within the predetermined range (step S4: YES), the power required for power supply can be covered by the discharged power of the first power storage device 11, and the first power storage device 11 can store the power required for power storage. . For this reason, the control apparatus 13 discharges from the 1st electrical storage apparatus 11 according to a power supply request | requirement, or charges from the 1st electrical storage apparatus 11 according to an electrical storage request | requirement (step S5).

  That is, as shown in FIGS. 6A (b) and 6B (b), the electric power W1 corresponding to the power Wd of the power supply request is discharged from the first power storage device 11, or FIGS. 6C (b) and 6D (b) As shown, the power W1 corresponding to the power Wc required for power storage is stored in the first power storage device 11. In FIG. 6, the power required for power supply and the discharge power are indicated by an upward (positive direction) arrow vector, and the power required for storage and the charge power are indicated by a downward (negative direction) arrow vector.

  On the other hand, if the first SOC is not within the predetermined range (step S4: NO), the control device 13 determines whether or not the request from the external controller is a power supply request (step S6). If it is a power supply request (step S6: YES), the total power of the discharge power or charge power of the first power storage device 11 and the discharge power or charge power of the second power storage device 12 becomes the power Wd of the power supply request. As described above, the first power storage device 11 is discharged or charged, and the second power storage device 12 is discharged or charged.

  For example, when the power supply request is made, if the first SOC is larger than a predetermined range (step S7: YES), the first power storage device 11 is discharged and the second power storage device 12 is charged so that the first SOC is at or near the predetermined range. Let Therefore, the control device 13 discharges the first power storage device 11 so that the total power of the discharge power of the first power storage device 11 and the charge power of the second power storage device 12 becomes the power required for power supply, and the second The power storage device 12 is charged (step S8). However, it is assumed that the power storage system 10 is designed so that the power Wd requested for power supply does not exceed the allowable output power of the first power storage device 11. In this case, as shown in FIG. 6A (a) and FIG. 6B (a), the discharge power W1 of the first power storage device 11−the charge power W2 of the second power storage device 12 = the power Wd of the power supply request. Thus, the discharge power W1 of the first power storage device 11 covers the power Wd requested for power supply, and the remaining power W2 is charged in the second power storage device 12. As a result, it is possible to respond to a power supply request while reducing the first SOC so that the first SOC is within or close to a predetermined range.

  On the other hand, when the first SOC is smaller than the predetermined range at the time of the power supply request (step S7: NO), the control device 13 determines whether or not the power of the power supply request is a high power output (step S9). Here, when the power of the power supply request is equal to or greater than the allowable output power of the second power storage device 12, it is determined that the power is a high power output.

  When the power required for the power supply is a high power output (step S9: YES), the first power storage device 11 is discharged and the second power storage device 12 is controlled so as to suppress the first SOC from being further reduced from the predetermined range. Is discharged. Therefore, the control device 13 discharges the first power storage device 11 so that the total power of the discharge power of the first power storage device 11 and the discharge power of the second power storage device 12 becomes the power required for power supply, and the second The power storage device 12 is discharged (step S10). In this case, as shown in FIG. 6A (c), the discharge power W1 of the first power storage device 11 + the discharge power W2 of the second power storage device 12 = the power Wd of the power supply request. The discharge power W2 of the second power storage device 12 is less than or equal to the allowable output power of the second power storage device 12. Therefore, the power Wd requested for power supply is covered by the discharge power W2 of the second power storage device 12, and the first power storage device 11 discharges the insufficient power W1. Thereby, it is possible to respond to a power supply request while suppressing a decrease in the first SOC due to discharge.

  When the power required for power supply is a high power output (step S9: YES), control device 13 discharges first power storage device 11 and second power storage device 12 when the first SOC is less than 0%. It may be prohibited. In this case, the power storage system 10 may be stopped. Thereby, the overdischarge of the 1st electrical storage apparatus 11 is prevented, and deterioration of the electric power storage system 10 can be suppressed.

  On the other hand, when the power required for power supply is not a high power output (step S9: NO), the first power storage device 11 is charged and the second power storage device 12 is discharged so that the first SOC is within a predetermined range or close thereto. Therefore, the control device 13 charges the first power storage device 11 so that the total power of the charging power of the first power storage device 11 and the discharge power of the second power storage device 12 becomes the power required for power supply, and the second The power storage device 12 is discharged (step S11). In this case, as shown in FIG. 6B (c), the discharge power W2 of the second power storage device 12−the charge power W1 of the first power storage device 11 = the power Wd of the power supply request. The discharge power W2 of the second power storage device 12 is equal to or less than the allowable output power of the second power storage device 12. As a result, the power Wd requested for power supply is covered by the discharge power W2 of the second power storage device 12, and the remaining power W1 is charged in the first power storage device 11. Thereby, it is possible to respond to the power supply request while increasing the first SOC.

  Further, when it is determined in step S6 that it is not a power supply request but a power storage request (step S6: NO), the discharge power or charge power of the first power storage device 11 and the discharge power or charge power of the second power storage device 12 The first power storage device 11 is discharged or charged and the second power storage device 12 is discharged or charged so that the total power becomes the power Wc required for power storage.

  For example, when the first SOC is less than a predetermined range at the time of the power storage request (step S12: YES), the first power storage device 11 is charged and the second power storage device 12 is discharged so that the first SOC is at or near the predetermined range. Let Therefore, the control device 13 charges the first power storage device 11 so that the total power of the charging power of the first power storage device 11 and the discharge power of the second power storage device 12 becomes the power required for power storage, The power storage device 12 is discharged (step S13). However, it is assumed that the power storage system 10 is designed so that the power Wc required for power storage does not exceed the allowable input power of the first power storage device 11. In this case, as shown in FIG. 6C (c) and FIG. 6D (c), the charging power W1 of the first power storage device 11−the discharging power W2 of the second power storage device 12 = the power Wc of the power storage request. The discharge power W2 of the second power storage device 12 is less than or equal to the allowable output power of the second power storage device 12. As a result, since the first power storage device 11 is charged with the power Wc required for power storage and the discharge power W2 of the second power storage device 12, the first SOC can be increased to approach or reach a predetermined range. .

  On the other hand, when the first SOC is greater than the predetermined range (step S12: NO), the control device 13 determines whether or not the power required for storage is a high power input (step S14). Here, when the power required for the power storage is equal to or higher than the allowable input power of the second power storage device 12, it is determined that the power is a high power input (step S14: YES). In this case, the first power storage device 11 is charged and the second power storage device 12 is charged so as to suppress the first SOC from being further larger than the predetermined range. Therefore, the control device 13 charges the first power storage device 11 so that the total power of the charging power of the first power storage device 11 and the charging power of the second power storage device 12 becomes the power required for storage, and the second The power storage device 12 is charged (step S15). In this case, as shown in FIG. 6C (a), the charging power W1 of the first power storage device 11 + the charging power W2 of the second power storage device 12 = the power Wc of the power storage request. The charging power W2 of the second power storage device 12 is equal to or less than the allowable input power of the second power storage device 12. As a result, the power Wc required for power storage is stored in the second power storage device 12, and the surplus power W1 is stored in the first power storage device 11, thereby suppressing the increase in the first SOC due to power storage while responding to the power storage request. it can.

  When the power required for the power storage is a high power input (step S14: YES), control device 13 prohibits charging of first power storage device 11 and second power storage device 12 when the first SOC is 100% or more. May be. In this case, the power storage system 10 may be stopped. Thereby, the overcharge of the 1st electrical storage apparatus 11 is prevented, and deterioration and thermal runaway of the electric power storage system 10 can be suppressed.

  On the other hand, when the power required for power storage is not a high power input (step S14: NO), the first power storage device 11 is discharged and the second power storage device 12 is charged so that the first SOC is within a predetermined range or close to it. Therefore, the control device 13 discharges the first power storage device 11 so that the total power of the discharge power of the first power storage device 11 and the charge power of the second power storage device 12 becomes the power required for power storage, and the second The power storage device 12 is charged (step S16). In this case, as shown in FIG. 6D (a), the charging power W2 of the second power storage device 12−the discharging power W1 of the first power storage device 11 = the power Wc of the power storage request. The charging power W2 of the second power storage device 12 is equal to or less than the allowable input power of the second power storage device 12. Thereby, the second power storage device 12 stores the power Wc of the power storage request, responds to the power storage request, stores the discharge power W1 of the first power storage device 11, and reduces the first SOC to a predetermined range or a value close thereto. Can do.

  According to the above configuration, the first power storage device 11 is discharged or charged according to the power supply request and the power storage request, and the second power storage device 12 is discharged or charged according to the remaining capacity of the first power storage device 11. Thereby, the power storage system 10 can achieve both high energy density and high power density more reliably.

  For example, when there is no power supply request and power storage request, if the first SOC is not within a predetermined range, the second power storage device 12 is discharged or charged so that the first SOC is at or near the predetermined range. As a result, the first SOC is adjusted within a predetermined range, so that the situation where the first SOC is small and the first power storage device 11 cannot be discharged, and the situation where the first SOC is small and the first power storage device 11 cannot be charged are avoided. Can do.

  Further, when there is a power supply request, if the first SOC is not within the predetermined range, the total power of the discharge power or charge power of the first power storage device 11 and the discharge power or charge power of the second power storage device 12 is the power supply request. The first power storage device 11 is discharged or charged and the second power storage device 12 is discharged or charged so that it becomes electric power. As a result, the first power storage device 11 or the second power storage device 12 can supply the power required for power supply, and the first SOC can be prevented from leaving the predetermined range.

  Further, when there is a power storage request, if the first SOC is not within the predetermined range, the total power of the discharge power or charge power of the first power storage device 11 and the discharge power or charge power of the second power storage device 12 is the power storage request. The first power storage device 11 is discharged or charged and the second power storage device 12 is discharged or charged so that it becomes electric power. Thereby, while the electric power of an electrical storage request | requirement is covered by the 1st electrical storage apparatus 11 or the 2nd electrical storage apparatus 12, it can suppress that 1st SOC leaves | separates from the predetermined range.

(Embodiment 2)
The configuration of the power storage system 10 according to the second embodiment will be described with reference to FIG. The power storage system 10 further includes an electric circuit 17 that can connect and disconnect the first power storage device 11 and the second power storage device 12 without using a charge / discharge control circuit.

  Specifically, a first DC / DC converter 18 is connected in series to the first power storage device 11, and a second DC / DC converter 19 is connected in series to the second power storage device 12. The first power storage device 11 and the second power storage device 12 are connected in parallel via a first DC / DC converter 18 and a second DC / DC converter 19. The first DC link 20 between the first power storage device 11 and the first DC / DC converter 18 and the second DC link 21 between the second power storage device 12 and the second DC / DC converter 19 are connected by the electric circuit 17. The switch 17 is provided in the electric circuit 17.

  The control device 13 controls the first power storage device 11 by the first DC / DC converter 18 and controls the second power storage device 12 by the second DC / DC converter 19. In addition, the control device 13 controls the switch 22 to connect or cut off the electric circuit 17 between the first power storage device 11 and the second power storage device 12. In this way, when the electric circuit 17 is connected, the first power storage device 11 and the second power storage device 12 are directly connected without going through the charge / discharge circuit such as the first DC / DC converter 18 and the second DC / DC converter 19. .

  For example, when charging the discharge power of the first power storage device 11 into the second power storage device 12 or when charging the discharge power of the second power storage device 12 into the first power storage device 11, the control device 13 controls the switch 22. Then, the electric circuit 17 is connected. As a result, the power output from one of the first power storage device 11 and the second power storage device 12 is input to the other device without passing through the first DC / DC converter 18 and the second DC / DC converter 19. Therefore, power loss in the first DC / DC converter 18 and the second DC / DC converter 19 can be reduced.

  Further, for example, when the discharge power from the second power storage device 12 is supplied to an external device (not shown) without charging the first power storage device 11, the control device 13 controls the switch 22 to 17 is shut off. Thereby, the electric power output from the second power storage device 12 is supplied to the external device via the second DC / DC converter 19. Therefore, the electric power according to the power supply request can be supplied from the power storage system 10 to the external device.

  The power storage system 10 in FIG. 7 includes the first DC / DC converter 18 and the second DC / DC converter 19. On the other hand, if charging / discharging of the 1st electrical storage apparatus 11 and the 2nd electrical storage apparatus 12 can be controlled, either one of the 1st DC / DC converter 18 and the 2nd DC / DC converter 19 will be provided in the electric power storage system 10. It only has to be.

  From the above description, many modifications and other embodiments of the present invention will be apparent to persons skilled in the art. Accordingly, the foregoing description should be construed as illustrative only and is provided for the purpose of teaching those skilled in the art the best mode of carrying out the invention. The details of the structure and / or function may be substantially changed without departing from the spirit of the invention.

  INDUSTRIAL APPLICABILITY The power storage system and the control method thereof according to the present invention are useful as a power storage system and a control method thereof that can achieve both high energy density and high power density more reliably.

10: Power storage system 11: First power storage device 12: Second power storage device 13: Control device 17: Electric circuit

Claims (10)

The first power storage device and the second power storage device are connected in parallel to each other, the output density of the first power storage device is higher than the output density of the second power storage device, and the energy density of the second power storage device is In the power storage system, which is higher than the energy density of the first power storage device,
Discharging or charging the first power storage device according to a power supply request and a power storage request;
A control method for an electric power storage system, wherein the second power storage device is discharged or charged according to a remaining capacity of the first power storage device.   If the remaining capacity of the first power storage device is not within a predetermined range when there is no power supply request and the power storage request, the second power storage device is set so that the remaining capacity of the first power storage device is at or near the predetermined range. The method for controlling the power storage system according to claim 1, wherein the power storage system is discharged or charged.   When there is a power supply request and the remaining capacity of the first power storage device is not within a predetermined range, the total power of the discharge power or charge power of the first power storage device and the discharge power or charge power of the second power storage device 3. The method for controlling the power storage system according to claim 1, wherein the first power storage device is discharged or charged and the second power storage device is discharged or charged so that the power of the power supply request is obtained.   When there is a power supply request, if the remaining capacity of the first power storage device is greater than the predetermined range, the first power storage device is discharged so that the remaining capacity of the first power storage device is at or near the predetermined range. The method for controlling the power storage system according to claim 3, wherein the second power storage device is charged.   When there is a power supply request, if the remaining capacity of the first power storage device is less than the predetermined range, the remaining capacity of the first power storage device is set to or close to the predetermined range, or the first power storage device 4. The control of the power storage system according to claim 3, wherein the first power storage device is discharged or charged and the second power storage device is discharged so as to suppress a remaining capacity of the battery from being further reduced from the predetermined range. Method.   If the remaining capacity of the first power storage device is not within a predetermined range when the power storage request is present, the total power of the discharge power or charge power of the first power storage device and the discharge power or charge power of the second power storage device 6. The power storage system according to claim 1, wherein the first power storage device is discharged or charged and the second power storage device is discharged or charged so that power becomes the power required by the power storage. Control method.   When there is a power storage request, if the remaining capacity of the first power storage device is less than the predetermined range, the first power storage device is charged so that the remaining capacity of the first power storage device is at or near the predetermined range. And controlling the power storage system according to claim 6, wherein the second power storage device is discharged.   If the remaining capacity of the first power storage device is greater than the predetermined range when the power storage request is made, the remaining capacity of the first power storage device is set to or close to the predetermined range, or the first power storage device The control of the power storage system according to claim 6, wherein the first power storage device is discharged or charged and the second power storage device is charged so as to prevent the remaining capacity of the battery from further exceeding the predetermined range. Method. The power storage system includes an electric circuit that can connect and disconnect the first power storage device and the second power storage device without using a charge / discharge control circuit,
When charging the second power storage device with the discharge power of the first power storage device, or when charging the first power storage device with the discharge power of the second power storage device, the first power storage device and the second power storage device The method for controlling the power storage system according to any one of claims 1 to 8, wherein the device is connected to the apparatus. A first power storage device;
A second power storage device connected in parallel to the first power storage device;
A control device for controlling the first power storage device and the second power storage device,
The output density of the first power storage device is higher than the output density of the second power storage device, and the energy density of the second power storage device is higher than the energy density of the first power storage device,
The controller is
Discharging or charging the first power storage device according to a power supply request and a power storage request;
A power storage system configured to discharge or charge the second power storage device according to a remaining capacity of the first power storage device.

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