JP6301206B2 - Power storage device and control program - Google Patents

Description

  The present invention relates to a power storage device that supplies power to a load, and a control program therefor.

  In recent years, various power storage devices using storage batteries have been developed. For example, Patent Document 1 proposes an uninterruptible power supply that supplies power from a storage battery to a load and maintains the power supply to the load when an abnormality occurs in an AC power supply that supplies AC power to the load. ing. The uninterruptible power supply of Patent Literature 1 includes two power input units to which current from an AC power source is input, and a power output unit connected to each power input unit via a switching unit. When an abnormality occurs in one or both of the two power output units, the switching unit disconnects the connection between the power input unit and the power output unit where the abnormality has occurred, and connects the power output unit and the storage battery. Moreover, the uninterruptible power supply of patent document 1 is comprised so that an output track, a power input part, and a storage battery can be cut away.

  Moreover, in the uninterruptible power supply of Patent Document 1, an overcurrent detection unit configured by a circuit breaker is provided between the switching unit and each power input unit. For example, when the AC power supply fails due to a short circuit and an overcurrent is input to each power input unit, the circuit breaker of the overcurrent detection unit is turned off, and the connection between each power input unit and the switching unit is cut off.

JP 2004-254470 A

  By the way, in the uninterruptible power supply of Patent Document 1, when a load with a large inrush current is connected to the power output unit, such as a non-inverter refrigerator equipped with a motor, an overcurrent is applied to the power input unit when starting this load. May be entered. However, in general, since the circuit breaker current threshold is set to be constant regardless of the current flow time, when an overcurrent exceeding the current threshold is input to the power input unit, the overcurrent detection unit is And immediately disconnects the connection with the switching unit.

  As described above, in the uninterruptible power supply of Patent Document 1, for example, when a load having a large inrush current is activated, a malfunction that the connection between the power input unit and the switching unit is interrupted when there is no abnormality in the alternating current is caused. May occur.

  Therefore, an object of the present invention is to provide a power storage device that can reduce the occurrence of malfunctions and a control program therefor.

  The present invention is a power storage device that supplies power to a load, the lithium ion storage battery, an external power supply mode that supplies power from an external power source to the load, and supplies power from the lithium ion storage battery to the load A switching unit that switches between battery power supply modes and a connection path that electrically connects the external power source and the switching unit, and when an overcurrent flows through the connection path for a predetermined time, the connection between the external power source and the switching unit When the current exceeding the current threshold flows through the connection path and the allowable time for allowing the current greater than the current threshold has passed, the connection between the external power supply and the switching unit is established. And a control unit that controls the blocking means so as to block. The current threshold changes according to the allowable time so that the current threshold decreases as the allowable time increases.

  The control unit of the power storage device has a blocking means so as not to cut off the connection between the external power source and the switching unit until an allowable time elapses when a current having a magnitude equal to or greater than the current threshold flows from the external power source to the switching unit. To control. In addition, the current threshold used for determining whether or not to disconnect the connection between the external power source and the switching unit changes according to the allowable time so that the current threshold decreases as the allowable time increases. According to such a configuration, even when a load having a large inrush current, such as a load including a motor, is connected to the power storage device and a large current flows at the time of activation of the load, the load has a certain amount of time. The current is allowed. That is, even in such a case, it is possible to suppress the immediate disconnection of the connection between the external power source and the switching unit, and as a result, it is possible to reduce the occurrence of malfunction in the power storage device.

  The power storage device may further include another blocking unit that is provided in the connection path and that blocks the connection between the external power source and the switching unit after the blocking unit when an overcurrent flows. By providing a plurality of shut-off means in this way, the switching unit and the like can be reliably protected from overcurrent.

  In the above power storage device, the current threshold is set in advance and a non-overcurrent threshold having a magnitude equal to or smaller than the rated current value of another interrupting means, and the overcurrent threshold that is preset and larger than the rated current value of another interrupting means And may be included. By setting such an overcurrent threshold, disconnection of the connection between the external power source and the switching unit due to inrush current or the like can be more reliably suppressed.

  In the above power storage device, the current threshold value may include a plurality of overcurrent threshold values. Thus, by setting a plurality of overcurrent thresholds in stages, the connection between the external power supply and the switching unit is cut off in an appropriate allowable time according to the magnitude of the current input from the external power supply to the power storage device. be able to.

In the power storage device, the plurality of overcurrent threshold values may be set along a curve represented by the following expression (1) in a coordinate system in which the current I is on the vertical axis and the time t is on the horizontal axis. Here, k is a constant determined so that the curve represented by the following expression (1) is positioned below the operation characteristic curve of another blocking means in the coordinate system.

  According to the above configuration, since the overcurrent threshold is regularly set, the magnitude and time of the input current that can be allowed by the power storage device can be easily grasped.

  In the power storage device, the control unit may detect a state of the power storage device and set a current threshold value according to the state of the power storage device. According to this configuration, it is possible to control the operation of the blocking unit using an appropriate current threshold value according to the state of the power storage device.

  The state of the power storage device may include a current value flowing through the connection path. In addition, the control unit can set the current threshold value so that the current threshold value is larger than the detected current value. According to this configuration, the operation of the cutoff means can be controlled by an appropriate current threshold corresponding to the current input from the external power supply.

  The state of the power storage device may include a temperature in the power storage device. Further, the control unit can reduce the value of the current threshold when the detected temperature rises. According to this configuration, when the temperature in the storage battery becomes high, the connection between the external power source and the switching unit can be quickly cut off.

  The present invention is a control program for a power storage device that supplies power to a load. The power storage device includes a lithium ion storage battery, an external power supply mode that supplies power from an external power source to the load, and a lithium ion storage battery. A switching unit that switches between the battery power supply mode for supplying the power to the load and a connection path that electrically connects the external power source and the switching unit, and when an overcurrent flows through the connection path for a predetermined time, And a blocking means for blocking the connection between the power source and the switching unit. The control program cuts off the connection between the external power supply and the switching unit when a current greater than or equal to the current threshold flows through the connection path and an allowable time for allowing a current greater than or equal to the current threshold has elapsed. The computer is caused to execute a function of controlling the blocking means. The current threshold changes according to the allowable time so that the current threshold decreases as the allowable time increases.

  According to the present invention, occurrence of malfunction of the power storage device can be reduced.

FIG. 1 is a functional block diagram illustrating a configuration example of a power storage device according to an embodiment of the present invention. FIG. 2 is a functional block diagram illustrating a more specific configuration example of the power storage device illustrated in FIG. 1. FIG. 3 is a flowchart when the control unit controls the shut-off means in the power storage device shown in FIG. FIG. 4 is a diagram illustrating an example of operating characteristics of the two circuit breakers and the circuit breaker in the power system in the power storage device illustrated in FIG. 1. FIG. 5 is a diagram illustrating an example of operation characteristics of two circuit breakers and a circuit breaker in a power system in the modification of the power storage device illustrated in FIG. 1. FIG. 6 is a diagram illustrating an example of operating characteristics of two circuit breakers and a circuit breaker for wiring in the power system in another modification of the power storage device illustrated in FIG. 1. FIG. 7 is a diagram illustrating an example of operating characteristics of two circuit breakers and a circuit breaker for wiring in a power system in still another modification of the power storage device illustrated in FIG. 1.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, about the structure which is the same or corresponds in a figure, the same code | symbol is attached | subjected and the same description is not repeated.

[Configuration of power storage device]
As shown in FIG. 1, the power storage device 1 according to the present embodiment includes a lithium ion storage battery 11, a switching unit 12, a blocking unit 13, another blocking unit 14, and a control unit 15. As illustrated in FIG. 2, the power storage device 1 may further include a battery management unit 16, a power supply unit 17, a conversion unit 18, a communication unit 19, a current detector D, and a rectifier R. Good. The lithium ion storage battery 11, the switching unit 12, the shut-off means 13 and 14, the control unit 15, the battery management unit 16, the power supply unit 17, the conversion unit 18, the communication unit 19, the current detector D, and the rectifier R are provided as a casing. In the frame 4. The power storage device 1 receives AC power from an electric power system as an external power source via the AC input terminal 2 and outputs AC power to the load 20 via the AC output terminal 3. Hereinafter, a configuration example of the power storage device 1 will be specifically described.

(Lithium ion storage battery)
The power storage device 1 includes one or more lithium ion storage batteries 11. When the power storage device 1 includes a plurality of lithium ion storage batteries 11, for example, as shown in FIG. 2, the battery packs 110 a and 110 b may be configured by the plurality of lithium ion storage batteries 11. Each battery pack 110a, 110b can be provided with monitoring units 111a, 111b.

  Each monitoring part 111a, 111b and the battery management part 16 to be described later are connected to the AC input terminal 2 without being insulated. Therefore, each monitoring part 111a, 111b and the battery management part 16 operate | move in the non-insulating part with respect to the alternating current input terminal 2, ie, the primary side into which alternating current power is input.

  Each monitoring part 111a, 111b monitors the state of each lithium ion storage battery 11 included in the battery packs 110a, 110b. Each monitoring part 111a, 111b detects the battery temperature of the lithium ion storage battery 11, a battery current, a battery voltage, remaining amount, etc., for example. Each of the monitoring units 111 a and 111 b transmits a signal or data indicating the detected state of the lithium ion storage battery 11 to the battery management unit 16.

  The monitoring units 111a and 111b may include switches 112a and 112b, respectively. When the monitoring units 111a and 111b detect an abnormality in the lithium ion storage battery 11, the monitoring units 111a and 111b turn off the switches 112a and 112b, and disconnect the connection between the conversion unit 18 and the lithium ion storage battery 11 described later.

  In the example of FIG. 2, the power storage device 1 is provided with two battery packs 110a and 110b. However, the power storage device 1 may be provided with only one battery pack, or three or more battery packs. It can also be provided. Moreover, the lithium ion storage battery 11 does not necessarily need to be provided in the power storage device 1 in the form of a battery pack, and may be incorporated in the power storage device 1 in an appropriate form in consideration of required power, usage environment, and the like.

(Switching part)
The switching unit 12 switches between an external power supply mode for supplying power from the power system to the load 20 and a battery power supply mode for supplying power from the lithium ion storage battery 11 to the load 20. When the switching unit 12 switches from the external power supply mode to the battery power supply mode, for example, when detecting a decrease or stop of AC power from the power system, the switching unit 12 connects the power system and the load 20 to the lithium ion storage battery 11. Switch to the connection with the load 20. In addition, when the switching unit 12 switches from the battery power supply mode to the external power supply mode, for example, when the power system recovers from an abnormality, the connection between the lithium ion storage battery 11 and the load 20 is switched between the power system and the load 20. Switch to connection.

  Although the switching part 12 is not specifically limited, For example, it can be comprised by well-known changeover switches, such as a relay. For example, in the external power supply mode, the connection between the power system and the load 20 is secured, while in the battery power supply mode, the relay is switched to cut off the connection between the power system and the load 20 and the lithium ion storage battery 11 A load 20 can be connected.

  In the present embodiment, switching control between the external power supply mode and the battery power supply mode in the switching unit 12 is performed by the control unit 15. However, a dedicated circuit may be provided separately from the control unit 15 and the switching control in the switching unit 12 may be performed by this dedicated circuit.

(Blocking means)
The blocking means 13 is provided in the connection path P. In the present embodiment, the blocking means 13 is provided between another blocking means 14 and the switching unit 12. However, the interruption | blocking means 13 may be provided between the interruption | blocking means 14 and an electric power grid | system. When the overcurrent flows through the connection path P, the interruption unit 13 interrupts the connection between the power system and the switching unit 12 before the interruption unit 14. The “overcurrent” is, for example, a current that exceeds the rated current of the interruption means 14. However, the present invention is not particularly limited to this, and a current exceeding any predetermined current value can be defined as an “overcurrent”.

  The interruption | blocking means 13 is a circuit breaker which interrupts | blocks wiring according to control from the outside, for example, includes switches, such as a relay. The shut-off means 13 switches the switch ON / OFF according to the control of the control unit 15.

(Another blocking means)
The interruption | blocking means 14 is provided in the connection path | route P which electrically connects an electric power grid | system and the switch part 12. FIG. The shut-off means 14 shuts off the connection between the power system and the switching unit 12 when an overcurrent flows through the connection path P for a predetermined time. However, the cutoff means 14 is configured to cut off the connection between the power system and the switching unit 12 after the cutoff means 13. That is, when the connection between the power system and the switching unit 12 is blocked by the blocking unit 13, the blocking unit 14 does not perform an operation for blocking the connection between the power system and the switching unit 12.

  The interruption | blocking means 14 is a circuit breaker for wiring which has the mechanism for interrupting | blocking wiring itself, and does not require the control from the outside especially. Although it does not specifically limit as the interruption | blocking means 14, For example, various fuses, such as a breaker and a slow blow fuse, etc. can be used. The interruption | blocking means 14 has an operation characteristic prescribed | regulated by the electric current value which flows into wiring, and the interruption | blocking time until it interrupts | blocks a wiring. The operating characteristic of the blocking means 14 is usually represented by an operating characteristic curve that varies inversely in a coordinate system with the current on the vertical axis and the time on the horizontal axis. That is, after the overcurrent flows in the connection path P, the time until the cutoff means 14 cuts off the connection between the power system and the switching unit 12 is shorter as the magnitude of the overcurrent becomes larger. The smaller it is, the longer it is.

(Control part)
Control unit 15 controls the operation of power storage device 1. The control unit 15 performs, for example, charge / discharge control of the lithium ion storage battery 11 and switching control between the external power supply mode and the battery power supply mode in the switching unit 12. The control unit 15 also controls the operation of the blocking means 13. Details of the control of the blocking means 13 by the control unit 15 will be described later.

  The control unit 15 may include, for example, a dedicated or general-purpose processor and a memory. In the control unit 15, the processor executes the control program stored in the memory, so that the lithium ion 11, the switching unit 12, the blocking unit 13, and the like can be controlled.

(Battery Management Department)
As described above, the battery management unit 16 can receive a signal or data indicating the state of the lithium ion storage battery 11 from the monitoring units 111a and 111b. The signal or data indicating the state of the lithium ion storage battery 11 received by the battery management unit 16 is transmitted to the outside through the control unit 15 and / or the communication unit 19, for example.

(Power supply unit)
The power supply unit 17 supplies power to each unit of the power storage device 1 using the power input from the AC input terminal 2 as a power source. The power supply unit 17 is connected to the AC input terminal 2, the control unit 15, the battery management unit 16, and the conversion unit 18, for example. The power supply unit 17 may be further connected to the monitoring units 111a and 111b and the communication unit 19 of the battery packs 110a and 110b. The power supply unit 17 converts the power input from the AC input terminal 2 into an appropriate voltage and outputs it to each unit of the power storage device 1.

  With such a configuration, the power consumed in the power storage device 1 can be supplied not by the power of the lithium ion storage battery 11 but by power from the outside. Therefore, more power can be supplied from the lithium ion storage battery 11 to the load 20. However, the power storage device 1 may have a configuration in which the power input from the AC input terminal 2 and the power supplied from the lithium ion storage battery 4 are used in combination or a configuration in which these are switched.

(Conversion unit)
The converter 18 converts AC power input from the AC input terminal 2 into DC power and outputs the DC power to the lithium ion storage battery 11. Moreover, the converter 18 converts the DC power output from the lithium ion storage battery 11 into AC power.

  The conversion unit 18 can include, for example, an inverter 181 and a DC / DC converter 182. The inverter 181 is connected to the AC input terminal 2, the AC output terminal 3, and the DC / DC converter 182. The inverter 181 converts AC power input from the AC input terminal 2 via the rectifier R into DC power and outputs the DC power to the DC / DC converter 182. The inverter 181 converts the DC power input from the DC / DC converter 182 into AC power, and supplies the AC power to the load 20 via the AC output terminal 3.

  The AC output terminal 3 may be, for example, an outlet that can connect the load 20. The forms of the AC input terminal 2 and the AC output terminal 3 are not limited to specific ones.

  The DC / DC converter 182 changes the voltage of the DC power output from the inverter 181 to a voltage suitable for the lithium ion storage battery 11 and outputs the DC power to the lithium ion storage battery 11. The DC / DC converter 182 changes the voltage of the DC power output from the lithium ion storage battery 11 to a voltage suitable for the load 20 and outputs the DC power to the inverter 181.

  Thus, the conversion part 18 can be reduced in size by comprising the conversion part 18 in a transformer-less system. The circuit configurations of the inverter 181 and the DC / DC converter 182 in the transformer-less converter 18 may be determined as appropriate.

  In addition, the structure of the conversion part 18 is not limited to the above-mentioned thing. For example, the conversion unit 18 can be configured by a combination of a rectifier that converts AC power to DC power and an inverter that converts DC power to AC power, a bidirectional inverter, or the like.

(Communication Department)
The communication unit 19 is a communication interface for the power storage device 1 to perform data communication with the outside. Communication between the communication unit 19 and the outside may be performed by wireless communication. The communication unit 19 can communicate with an external device connected to a network such as the Internet via an external router, for example.

  As described above, the communication unit 19 transmits the signal or data indicating the state of the lithium ion storage battery 11 received from the battery management unit 16 to, for example, an external management device (not shown). The communication unit 19 may further transmit the identification information of the power storage device 1, the information indicating the position, the information on the connection state with other devices, and the like to an external management device.

  The communication unit 19 may receive control data generated by an external management device based on a signal or data indicating the state of the lithium ion storage battery 11. The communication unit 19 can transmit this control data to the control unit 15. The control unit 15 may control the operation of the lithium ion storage battery 11 based on the received control data.

[Operation of power storage device]
Next, the operation of the power storage device 1 configured as described above will be described. In the present embodiment, in particular, the control of the blocking means 13 by the control unit 15 will be described in detail.

  FIG. 3 is a flowchart showing the control process of the blocking means 13 by the control unit 15. The control unit 15 detects the current flowing through the connection path P using the current detector D (step S1). More specifically, the current detector D constantly or periodically indicates the current flowing through the connection path P between the power system and the switching unit 12, that is, the current input from the power system to the power storage device 1 via the AC input terminal 2. And the detected current value is input from the current detector D to the control unit 15. The configuration of the current detector D is not particularly limited. For example, the current detector D can be configured using a known device such as a resistor.

  The control unit 15 determines whether or not the magnitude of the detected current is greater than or equal to the current threshold (step S2). The control unit 15 stores a plurality of preset current threshold values. Each current threshold is associated with an allowable time. More specifically, the current threshold used by the control unit 15 in the process of step S2 is determined according to the allowable time so that the current threshold decreases as the allowable time increases. The allowable time is a time during which a current having a magnitude equal to or larger than each current threshold can be allowed to flow through the connection path P.

  The plurality of current thresholds may include, for example, a non-overcurrent threshold having a magnitude equal to or smaller than the rated current value of the cutoff unit 14 and an overcurrent threshold larger than the rated current value of the cutoff unit 14. The control unit 15 may store at least one overcurrent threshold, but preferably stores a plurality of overcurrent thresholds. Moreover, the control part 15 should just memorize | store one or more non-overcurrent threshold values. When one non-overcurrent threshold value is stored in the control unit 15, this non-overcurrent threshold value is preferably a value smaller than the rated current of the cutoff means 14.

  When the magnitude of the detected current is greater than or equal to any of the plurality of current threshold values (YES in step S2), the control unit 15 corresponds to the maximum current threshold value among the current threshold values that are equal to or smaller than the detected current magnitude. It is determined whether the allowable time has elapsed (step S3). Hereinafter, the maximum current threshold value among the current threshold values equal to or smaller than the magnitude of the detected current is referred to as a maximum current threshold value.

  When a current equal to or greater than the maximum current threshold is detected in the connection path P and an allowable time corresponding to the maximum current threshold has elapsed, that is, when a current equal to or greater than the maximum current threshold flows for a corresponding allowable time (step S3). In the case of YES), the control unit 15 operates the blocking unit 13 to block the connection between the power system and the switching unit 12 (step S4). Specifically, the control unit 15 sends an electromagnetic signal for cutting off the connection between the power system and the switching unit 12 to the cutoff unit 13 and switches the switch of the cutoff unit 13 from ON to OFF by this electromagnetic signal.

  On the other hand, a current equal to or greater than the maximum current threshold is detected in the connection path P, but it is detected that the current flowing through the connection path P has decreased below the maximum current threshold before the allowable time corresponding to the maximum current threshold has elapsed. In the case (YES in step S2 and NO in step S3), the control unit 15 does not transmit an electromagnetic signal for blocking the connection between the power system and the switching unit 12 to the blocking unit 13. The control unit 15 does not block the connection between the power system and the switching unit 12, and returns to step S1 to continue the current detection in the connection path P. Subsequent processing (steps S2 to S4) is as already described.

  When the control unit 15 is configured by a dedicated or general-purpose processor and a memory, the processing in steps S1 to S4 may be performed by the processor executing a control program stored in the memory.

  Here, the processing of step S2 to step S4 will be described more specifically with reference to FIG.

In FIG. 4, a line indicated by a symbol OC ₁₃ represents an operating characteristic line of the blocking unit 13 controlled by the control unit 15 in a coordinate system in which the current I is on the vertical axis and the time t is on the horizontal axis. OC ₁₄ is an operating characteristic curve of the blocking means 14. OC _ps is an operating characteristic curve of a circuit breaker (breaker) for a distribution board (not shown) included in the power system.

In the coordinate system of FIG. 4, the operating characteristic line OC ₁₃ of the blocking means ₁₃ is located below the operating characteristic curve OC ₁₄ of the blocking means 14. That is, in FIG. 4, when an overcurrent exceeding the rated current of the interruption means 14 flows in the connection path P, the interruption means 13 operates before the interruption means 14 operates. It shows that the connection with the switching unit 12 is cut off. In the coordinate system of FIG. 4, the operating characteristic curve OC _ps of the circuit breaker for the distribution board is also located above the operating characteristic line OC ₁₃ of the breaking means 13.

The operating characteristic line _{OC 13} of the blocking means 13, three current threshold _{Th ex1, Th ex2, Th Nex} is present. The current threshold values Th _ex1 and Th _ex2 are overcurrent threshold values that are larger than the rated current value of the cutoff means 14. The current threshold value Th _Nex is a non-overcurrent threshold value that has a magnitude equal to or smaller than the rated current value of the cutoff means 14. The current threshold Th _Nex may be set to the same value as the rated current of the cutoff means 14 or may be set to a value smaller than the rated current of the cutoff means 14.

The overcurrent threshold _values Th _ex1 and Th _ex2 and the non-overcurrent threshold value Th _Nex are associated with allowable times t _ex1 , t _ex2 and t _Nex , respectively. The relationship between the overcurrent thresholds Th _ex1 and Th _ex2 and the non-overcurrent threshold Th _Nex is expressed by Th _ex1 > Th _ex2 > Th _Nex . The relationship between the allowable times t _ex1 , t _ex2 and t _Nex is represented by t _ex1 <t _ex2 <t _Nex . That is, in the example of FIG. 4, the current threshold changes according to the allowable time so that the current threshold increases as the allowable time decreases.

For example, when a current having a magnitude greater than or equal to the overcurrent threshold Th _ex1 is detected, the control unit 15 allows the current to flow until the allowable time t _ex1 elapses. When a current having a magnitude equal to or larger than the overcurrent threshold Th _ex1 flows for the allowable time t _ex1 , an electromagnetic signal is transmitted from the control unit 15 to the cutoff means 13. The cutoff means 13 receives this electromagnetic signal, turns off the switch, and cuts off the connection between the power system and the switching unit 12.

In the above case, since the magnitude of the detected current is equal to or greater than the overcurrent threshold Th _ex1 , the overcurrent threshold Th _ex2 and the non-overcurrent threshold Th _Nex are naturally exceeded. However, the determination in step S2 uses the maximum current threshold Th _ex1 among the current thresholds Th _ex1 , Th _ex2 , and Th _Nex that are equal to or smaller than the magnitude of the detected current. That is, the control unit 15 determines whether or not allowable time t _ex1 corresponding to the current threshold Th _ex1 has elapsed, when the allowable time t _ex1 has elapsed, controls the blocking means 13 power system and switching unit 12 is disconnected.

When it is detected that the current in the connection path P has decreased _{below the} overcurrent threshold Th _ex1 before the allowable time t _ex1 has elapsed, the control unit 15 does not operate the cutoff unit 13 and the power system and the switching unit 12 Do not block the connection. However, even when the detected current is lower than the overcurrent threshold Th _ex1 , if the overcurrent threshold Th _ex2 or more or the non-overcurrent threshold Th _Nex or more, as described below, the power system and the switching unit 12 may be disconnected.

When a current smaller than the overcurrent threshold Th _{ex1 and} larger than the overcurrent threshold Th _ex2 is detected, the control unit 15 allows the current to flow until the allowable time t _ex2 elapses. When a current smaller than the overcurrent threshold Th _{ex1 and} greater than the overcurrent threshold Th _ex2 flows for the allowable time t _ex2 , an electromagnetic signal is transmitted from the control unit 15 to the cutoff means 13. The cutoff means 13 receives this electromagnetic signal, turns off the switch, and cuts off the connection between the power system and the switching unit 12.

When it is detected that the current in the connection path P has decreased _{below the} overcurrent threshold Th _{ex2 before the} allowable time t _ex2 has elapsed, the control unit 15 does not operate the cutoff unit 13 and the power system and the switching unit 12 Do not block the connection. However, even if the detected current is lower than the overcurrent threshold Th _ex2 , the connection between the power system and the switching unit 12 may be interrupted as described below if the detected current is equal to or greater than the non-overcurrent threshold Th _Nex. is there.

When a current smaller than the overcurrent threshold Th _{ex2 and} greater than or _equal to the non-overcurrent threshold Th _Nex is detected, the control unit 15 allows the current to flow until the allowable time _tNex elapses. When a current that is smaller than the overcurrent threshold Th _{ex2 and} greater than or _equal to the non-overcurrent threshold Th _Nex flows for the allowable time t _Nex , an electromagnetic signal is transmitted from the control unit 15 to the cutoff means 13. The cutoff means 13 receives this electromagnetic signal, turns off the switch, and cuts off the connection between the power system and the switching unit 12.

[Effect of the embodiment]
As described above, in the power storage device 1 of the present embodiment, even when a current equal to or greater than the current threshold flows through the connection path P, the power system and the switching unit until the allowable time corresponding to the current threshold elapses. 12 is not cut off. In addition, the current threshold used for determining whether or not to disconnect the connection between the power system and the switching unit 12 changes according to the allowable time so that the current threshold decreases as the allowable time increases. For this reason, even when a load having a large inrush current, such as a non-inverter refrigerator including a motor, is connected to the power storage device 1 and a large current is input from the power system when starting the load, a certain amount of time is required. If so, this current can be allowed. Therefore, according to the power storage device 1, even when starting a load with a large inrush current, it is possible to prevent the connection between the power system and the switching unit 12 from being immediately interrupted. Generation can be reduced.

  By the way, in the case of a power storage device including a lead storage battery or the like, generally, a heavy load such as a non-inverter refrigerator is not connected. For this reason, in a power storage device including a lead storage battery or the like, there is no problem that a large current is input from the power system for load activation or the like, and the connection between the power system and the switching unit is immediately interrupted. On the other hand, since the said electrical storage apparatus 1 is equipped with the lithium ion storage battery 11 in which a high output is possible compared with a lead storage battery etc., when the alternating current power from an electric power system falls or stops etc., the lithium ion storage battery 11 carries out. It is possible to operate a heavy load. That is, a heavy load can be connected to the power storage device 1. For this reason, in the said electrical storage apparatus 1, when starting a heavy load, etc., when a big electric current is input from a power grid, it is necessary to prevent that a connection with a power grid and the switching part 12 is interrupted | blocked immediately. high.

  In general, many circuit breakers use bimetal that uses Joule integration. Such a circuit breaker has few malfunctions upon entry, but lacks the ability to instantaneously interrupt a short circuit. There are expensive products such as thermal electromagnetic circuit breakers, but such products are not suitable for inexpensive power storage devices.

  In general, when a load that is incompatible with the power storage device (for example, a load having a large inrush power or a load exceeding the rating) is connected, it is necessary to perform operations such as replacement of a fuse and a breaker recovery operation. Such work requires specialized knowledge and is difficult for many users. However, with the power storage device 1 according to the present embodiment, the user can restore the switching unit 12 and / or the blocking unit 13 by a simple button operation or remote operation.

  The switching unit 12 of the power storage device 1 performs switching from the external power supply mode to the battery power supply mode when a decrease or stop of the AC power from the power system is detected, and the load 20 is connected to the lithium ion storage battery 11. Connect to. In the present embodiment, as described above, since the connection between the power system and the switching unit 12 is suppressed when there is no abnormality in AC power, such as when the load is activated, the switching unit 12 is suppressed. It is possible to prevent unnecessary mode switching from occurring. As a result, the switching unit 12 can be protected.

  The power storage device 1 includes not only the blocking unit 13 but also another blocking unit 14. Therefore, the switching unit 12, the conversion unit 18, the electric wire, and the like can be reliably protected from overcurrent. However, in the power storage device 1, the blocking unit 14 may not be provided.

  In the power storage device 1, the non-overcurrent threshold and the overcurrent threshold are set in advance. The overcurrent threshold is set to be larger than the rated current value of the cutoff means 14. For this reason, the interruption | blocking with the electric power system by the inrush current etc. and the switch part 12 can be suppressed more reliably.

  In the power storage device 1, a plurality of overcurrent threshold values are set in advance. For this reason, according to the overcurrent input into the electrical storage apparatus 1 from an electric power grid | system, the connection of an electric power grid | system and the switch part 12 can be interrupted | blocked in appropriate permissible time.

[Modification]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

(1) In the above embodiment, an example in which two overcurrent thresholds Th _ex1 and Th _ex2 are set has been described, but three or more overcurrent thresholds may be set. In the example shown in FIG. 5, three overcurrent thresholds Th _ex1a , Th _ex2a , and Th _ex3a exist on the operating characteristic line OC _13a of the blocking means 13. Also in the example shown in FIG. 5, the operating characteristic line OC _{13 a} of the blocking means ₁₃ is located below the operating characteristic curve OC ₁₄ of the blocking means 14.

Even when the number of overcurrent thresholds increases, the control unit 15 controls the blocking means 13 in the same manner as in the above embodiment. That is, when the control unit 15 detects a current having a magnitude greater than any of the three overcurrent thresholds Th _ex1a , Th _ex2a , Th _ex3a and the non-overcurrent threshold Th _{Nex in} the connection path P, the control unit 15 sets the maximum current threshold. When the corresponding permissible time has elapsed, the blocking means 13 is operated to disconnect the connection between the power system and the switching unit 12.

In the example of FIG. 5, three overcurrent thresholds Th _ex1a , Th _ex2a , and Th _ex3a are set. However, as many overcurrent thresholds as possible are set so that the operating characteristic line OC _13a becomes closer to a curve. Is preferred.

(2) As illustrated in FIG. 6, the overcurrent threshold is set along a curve C represented by the following expression (1) in a coordinate system in which the current I is on the vertical axis and the time t is on the horizontal axis. You can also K in the following formula (1) is a constant determined so that the curve C is positioned below the operating characteristic curve OC ₁₄ of the blocking means 14. The value of k may be set as appropriate in consideration of the current consumption of the load 20 connected to the power storage device 1. FIG. 6 depicts a schematic shape of the curve C represented by the following formula (1), and does not depict the curve C strictly according to the following formula (1).

In operation characteristic line _{OC 13b} of the blocking means 13 in FIG. 6, along the curve C, 4 single overcurrent threshold _{Th ex1b, Th ex2b, Th ex3b} , Th ex4b is set. Thus, by regularly setting the overcurrent thresholds Th _ex1b , Th _ex2b , Th _ex3b , Th _ex4b , the magnitude and time of the current that can be allowed by the power storage device 1, that is, The magnitude and time of the current at which the connection with the switching unit 12 is not interrupted can be more easily grasped.

  (3) Although the current threshold is set in advance in the above embodiment, the control unit 15 can also detect the state of the power storage device 1 and set the current threshold according to the state of the power storage device 1.

(3-1) For example, as illustrated in FIG. 7, when detecting the current I _ex flowing through the connection path P, the control unit 15 can change the current threshold from Th _ex to Th _{ex ′} . The current threshold value Th _{ex ′} is a value smaller than the original current threshold value Th _{ex ′} and larger than the detection current I _ex . Although not particularly illustrated, when a current larger than the current threshold Th _ex is detected in the connection path P, a current threshold larger than the current threshold Th _ex and the detected current can be set.

  With such a configuration, the operation of the cutoff means 13 can be controlled using an appropriate current threshold corresponding to the magnitude of the current input from the power system to the power storage device 1. That is, even when the magnitude of the current input from the power system to the power storage device 1 varies according to the load 20 or the like connected to the power storage device 1, the operation of the cutoff means 13 is controlled according to the change. It becomes possible to do.

(3-2) Further, for example, the control unit 15 may detect the temperature in the power storage device 1. The controller 15 can also change the current threshold value Th _ex to a smaller current threshold value Th _{ex ′} when the temperature in the power storage device 1 rises. According to such a configuration, when the temperature in the power storage device 1 becomes high, the shut-off unit 13 can be operated quickly, and the connection between the power system and the switching unit 12 can be quickly shut off.

  (4) In the above embodiment, the control unit 15 that performs charge / discharge control of the lithium ion storage battery 11 and switching control of the switching unit 12 also performs control of the blocking means 13, but is not particularly limited thereto. . The power storage device 1 may include a control unit that controls the blocking means 13 separately from the control unit that performs charge / discharge control and switching control.

  (5) In the above embodiment, the control of the shut-off means 13 is performed by the control unit 15 provided in the power storage device 1, but the shut-off means 13 is shut off by executing a control program by a computer different from the power storage device 1. Control of the means 13 may be performed. The computer may include a dedicated or general-purpose processor and memory. In this case, the blocking unit 13 is controlled by the processor executing the control program stored in the memory.

  (6) In the above embodiment, the blocking means 13 is configured using a switch, but the configuration of the blocking means 13 is not particularly limited to this. For example, the inverter 181 can be a blocking means for blocking the connection between the power system and the switching unit 12. That is, when an allowable time for allowing a current larger than the current threshold to flow through the connection path P and allowing a current larger than the current threshold has elapsed, the control unit 15 turns off the inverter 181. The connection between the power system and the switching unit 12 can also be cut off.

  DESCRIPTION OF SYMBOLS 1: Power storage device, 11: Lithium ion storage battery, 12: Switching part, 13: Shut-off means, 14: Another shut-off means, 15: Control part

Claims (8)

A power storage device that supplies power to a load,
A lithium ion battery,
A switching unit that switches between an external power supply mode for supplying power from an external power source to the load and a battery power supply mode for supplying power from the lithium ion storage battery to the load;
A shut-off means provided in a connection path for electrically connecting the external power source and the switching unit, and shuts off the connection between the external power source and the switching unit when an overcurrent flows through the connection path for a predetermined time; ,
Provided in the connection path, the overcurrent flows in the connection path for a predetermined time, and when the blocking means blocks the connection between the external power source and the switching unit, the operation for blocking the connection is not performed, Another blocking means for blocking the connection when the blocking means fails to block the connection;
When a current larger than a current threshold flows through the connection path and an allowable time for allowing a current larger than the current threshold has elapsed, the connection between the external power source and the switching unit is changed to the other A control unit for controlling the blocking means to shut off before the blocking means;
With
The power storage device, wherein the current threshold changes according to the allowable time so that the current threshold decreases as the allowable time increases. The power storage device according to claim 1,
The another blocking means is a power storage device that blocks the connection without requiring external control. The power storage device according to claim 1 or 2,
The power storage device, wherein an operating characteristic line of the other shut-off means represented in a coordinate system with the current I on the vertical axis and the time t on the horizontal axis is set to be higher than the operating characteristic line of the shut-off means. The power storage device according to any one of claims 1 to 3,
The current threshold value includes a plurality of overcurrent threshold values. The power storage device according to claim 4,
The plurality of overcurrent thresholds are in a coordinate system in which the current I is on the vertical axis and the time t is on the horizontal axis.
The electrical storage apparatus set along the curve represented by following Formula (1).

Here, k is a constant determined so that the curve represented by the above formula (1) in the coordinate system is located below the operation characteristic curve of the other blocking means. The power storage device according to claim 1,
The control unit detects a state of the power storage device, and sets the current threshold according to the state of the power storage device. The power storage device according to claim 6,
The state of the power storage device includes the temperature in the power storage device,
The said control part is an electrical storage apparatus which makes the value of the said current threshold value small, when the said detected temperature rises. A control program for a power storage device that supplies power to a load,
The power storage device
A lithium ion battery,
A switching unit that switches between an external power supply mode for supplying power from an external power source to the load and a battery power supply mode for supplying power from the lithium ion storage battery to the load;
A shut-off means provided in a connection path for electrically connecting the external power source and the switching unit, and shuts off the connection between the external power source and the switching unit when an overcurrent flows through the connection path for a predetermined time; ,
Provided in the connection path, the overcurrent flows in the connection path for a predetermined time, and when the blocking means blocks the connection between the external power source and the switching unit, the operation for blocking the connection is not performed, Another blocking means for blocking the connection when the blocking means could not block the connection,
The control program is
When a current larger than a current threshold flows through the connection path and an allowable time for allowing a current larger than the current threshold has elapsed, the connection between the external power source and the switching unit is changed to the other A function of controlling the blocking means to shut off before the blocking means;
To the computer,
The control program, wherein the current threshold is changed according to the allowable time so that the current threshold decreases as the allowable time increases.

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