Power storage equipment, determination device, and computer program

Abstract

Power storage equipment according to the present invention comprises: a plurality of power storage elements which are connected to each other in parallel; and a connection circuit which connects the plurality of power storage elements to an external current supply source or current supply destination. The connection circuit includes: a first current path which is connected to the current supply source or current supply destination; a plurality of second current paths which branch off from the first current path and are respectively connected to the plurality of power storage elements; a first current sensor which measures a current flowing through the first current path; and a plurality of second current sensors which individually measure currents that respectively flow through the plurality of second current paths. The power storage equipment comprises a determination unit which uses a measurement result of the first current sensor and measurement results of the plurality of second current sensors to determine whether or not there is an abnormality in the connection circuit.

Description

Electricity storage facility, determination device, and computer program

[0001] The present disclosure relates to a power storage facility, a determination device, and a computer program.

[0002] Energy storage facilities that store electricity supplied from power generation facilities such as solar power generation facilities and wind power generation facilities and supply the stored electricity to loads such as factories and office buildings as needed are becoming widespread.Energy storage facilities are equipped with a large number of energy storage elements (energy storage modules or banks).

[0003] JP 2019-125482 A

[0004] Conventionally, when an abnormality occurs in an energy storage facility that includes a large number of energy storage elements, it is not easy to identify the location of the abnormality.

[0005] The present disclosure aims to provide a power storage facility, a determination device, and a computer program that can determine whether an abnormality has occurred in a connection circuit that connects a power storage element to a current supply source or a current supply destination.

[0006] The present disclosure provides an energy storage facility including a plurality of energy storage elements connected in parallel and a connection circuit connecting the plurality of energy storage elements to an external current supply source or a current supply destination. The connection circuit includes a first current path connected to the current supply source or the current supply destination, a plurality of second current paths branching from the first current path and connected to the plurality of energy storage elements, a first current sensor measuring a current flowing through the first current path, and a plurality of second current sensors measuring a current flowing through each of the plurality of second current paths. The energy storage facility includes a determination unit that determines whether or not there is an abnormality in the connection circuit using a measurement result of the first current sensor and a measurement result of the plurality of second current sensors.

[0007] According to the present disclosure, it is possible to determine whether an abnormality has occurred in a connection circuit that connects an energy storage element to a current supply source or a current supply destination.

[0008] It is a schematic diagram showing the overall configuration of a power storage system including a storage battery equipment (an example of a power storage equipment). It is a schematic diagram showing the internal configuration of the storage battery equipment. It is an explanatory diagram explaining the circuit configuration of the storage battery equipment. It is a flowchart explaining the procedure of processing executed by the storage battery equipment. It is a block diagram explaining the internal configuration of a monitoring server. It is a flowchart explaining the procedure of processing executed by the monitoring server.

[0009] (1) A power storage facility according to the present disclosure includes a plurality of power storage elements connected in parallel and a connection circuit connecting the plurality of power storage elements to an external current supply source or a current supply destination. The connection circuit includes a first current path connected to the current supply source or the current supply destination, a plurality of second current paths branching from the first current path and connected to the plurality of power storage elements, a first current sensor measuring a current flowing through the first current path, and a plurality of second current sensors measuring a current flowing through each of the plurality of second current paths. The power storage facility includes a determination unit that determines whether or not there is an abnormality in the connection circuit using a measurement result of the first current sensor and a measurement result of the plurality of second current sensors.

[0010] The power storage facility is a facility that is installed alongside a power generation facility such as a solar power generation facility or a wind power generation facility, stores the power supplied from the power generation facility, and supplies the stored power to a load. An example of the power storage facility is an energy storage system (ESS). Alternatively, the power storage facility may be a power conditioner, a backup power supply device, or the like.

[0011] The energy storage facility includes a plurality of energy storage elements connected in parallel. The energy storage elements are, for example, modules each configured by connecting a plurality of energy storage cells in series, or banks each configured by connecting a plurality of modules in series. In the following embodiment, a configuration of an energy storage facility including a plurality of banks will be described.

[0012] In energy storage facilities with multiple banks, it is important to be able to accurately measure the current of each bank. The accuracy of determining and estimating the operating state, degradation state, and expected lifespan of the energy storage facility is affected by the accuracy of the current measurement of each bank. Energy storage facilities, which are social infrastructure, are expected to operate at all times. It is necessary to prevent improper current measurement from leading to a false judgment that a bank is abnormal when in fact there is no problem with the bank, which would result in the shutdown of the energy storage facility.

[0013] Since a power storage facility such as an ESS has many banks, each bank is provided with a large number of current sensors, and in such facilities, there is a relatively high possibility that an abnormality will occur in the current sensors.

[0014] In the energy storage facility described in (1) above, the presence or absence of an abnormality in the connection circuit is determined using the measurement results of the first current sensor that measures the current flowing through the first current path and the measurement results of the multiple second current sensors that individually measure the currents flowing through the multiple second current paths, so it is possible to determine whether there is an abnormality in the current path or in the current sensor. Here, a current path abnormality refers to a state in which the resistance of the current path becomes high for some reason, causing the current that should normally flow through the current path to no longer flow. A current sensor abnormality refers to a state in which the current sensor no longer indicates the current value that it should normally indicate.

[0015] With the configuration (1) above, even if the measured current value indicates an abnormal value, the cause can be determined, and it is possible to prevent the operation of the power storage facility from being stopped due to an erroneous decision.

[0016] (2) In the energy storage equipment described in (1) above, the judgment unit may compare a current value indicating the magnitude of the current measured by the first current sensor with a total value indicating the sum of the magnitudes of the individual currents measured by the multiple second current sensors, compare a ratio of the individual internal resistance values ​​of the multiple energy storage elements with a ratio of the magnitudes of the individual currents measured by the multiple second current sensors, and judge the presence or absence of an abnormality in the connection circuit based on the comparison result between the current value and the total value and the comparison result between the ratio of the internal resistance values ​​and the magnitudes of the currents.

[0017] According to the storage equipment of (2) above, it is possible to determine whether or not there is an abnormality in the connection circuit including the first current path, the multiple second current paths, the first current sensor, and the multiple second current sensors, based on the comparison result between the current value measured by the first current sensor and the total value of the current measured by the second current sensor, and the comparison result between the ratio of the internal resistance values ​​and the ratio of the magnitude of the current flowing through each storage element.

[0018] (3) In the energy storage equipment described in (1) or (2) above, the determination unit may determine that there is an abnormality in the first current sensor when the current value and the total value differ and the ratio of the internal resistance values ​​and the ratio of the current magnitudes are substantially equal.

[0019] The energy storage facility of (3) compares the ratio of the internal resistance values ​​with the ratio of the magnitude of the current flowing through each energy storage element, and if it determines that the two are substantially equal, it can determine that there is no abnormality in the second current sensor that measures the current flowing through each energy storage element. If the current value measured by the first current sensor and the total value of the current measured by the second current sensor are different, the energy storage facility can determine that there is an abnormality in the first current sensor. Here, "the ratio of the internal resistance values ​​and the ratio of the magnitude of the current are substantially equal" means that they are completely equal and that they deviate from being completely equal within an allowable error range.

[0020] (4) In the energy storage facility described in any one of (1) to (3) above, the determination unit may determine that there is an abnormality in at least one of the second current sensors when the current value and the total value differ and the ratio of the internal resistance values ​​and the ratio of the current magnitudes differ.

[0021] If the ratio of the internal resistance values ​​and the ratio of the magnitudes of the currents flowing through the storage elements differ, there is a possibility that an abnormality exists in one of the second current sensors or that an abnormality exists in the second current path.If the current value of the current measured by the first current sensor differs from the total current value measured by the second current sensor, this means that at least one of the second current sensors did not indicate the current value that it should have indicated, and therefore the storage equipment can determine that at least one of the second current sensors is abnormal.

[0022] (5) In the energy storage facility described in any one of (1) to (4) above, the determination unit may determine that there is an abnormality in at least one of the second current paths when the current value and the total value are substantially equal and the ratio of the internal resistance values ​​and the ratio of the current magnitudes are different.

[0023] If the ratio of the internal resistance values ​​and the ratio of the magnitudes of the currents flowing through the energy storage elements differ, there is a possibility that an abnormality exists in one of the second current sensors or in the second current path. Furthermore, if the current value of the current measured by the first current sensor and the sum of the currents measured by the second current sensor are substantially equal, this means that there are no abnormalities in the first current sensor and the second current sensor, and the energy storage equipment can be determined to have an abnormality in at least one of the second current paths. Here, "the current value of the current measured by the first current sensor and the sum of the currents measured by the second current sensor being substantially equal" means both a case where the current values ​​are completely equal and a case where the current values ​​deviate from being completely equal within the allowable error range.

[0024] (6) In the energy storage facility described in any one of (1) to (5) above, the judgment unit may judge that there is no abnormality in the connection circuit when the current value and the total value are substantially equal and the ratio of the internal resistance values ​​and the ratio of the current magnitudes are substantially equal.

[0025] In the storage equipment of (6) above, if the current value of the current measured by the first current sensor is substantially equal to the total value of the current measured by the second current sensor, and the ratio of the internal resistance values ​​to the ratio of the magnitude of the current flowing through each storage element is substantially equal, it can be determined that there is no abnormality in the first current path, the multiple second current paths, the first current sensor, and the multiple second current sensors.

[0026] (7) In the energy storage facility described in any one of (1) to (6) above, the energy storage element is a module formed by connecting a plurality of energy storage cells in series, or a bank formed by connecting a plurality of such modules in series.

[0027] According to the storage facility of (7) above, it is possible to avoid the mistaken determination that an abnormality has occurred in a module or bank when in fact there is no problem with the module or bank due to improper current measurement.

[0028] (8) The determination device of the present disclosure includes an acquisition unit that acquires measurement results of the first current sensor and measurement results of the second current sensors from an energy storage facility that includes a connection circuit including a plurality of energy storage elements connected in parallel, a first current path connected to an external current source or a current destination, a plurality of second current paths branching from the first current path and respectively connected to the plurality of energy storage elements, a first current sensor that measures the current flowing in the first current path, and a plurality of second current sensors that individually measure the current flowing in each of the plurality of second current paths, and a determination unit that determines whether or not there is an abnormality in the connection circuit using the acquired measurement results of the first current sensor and the measurement results of the plurality of second current sensors.

[0029] According to the determination device of (8) above, even if the measured current value indicates an abnormal value, it is possible to determine the cause of the abnormal value and prevent the power storage facility from being stopped due to an erroneous determination.

[0030] (9) A computer program disclosed herein is a computer program for causing a computer to execute a process of acquiring measurement results of the first current sensor and the second current sensors from an energy storage facility including a connection circuit including a plurality of energy storage elements connected in parallel, a first current path connected to an external current source or a current destination, a plurality of second current paths branching from the first current path and respectively connected to the plurality of energy storage elements, a first current sensor measuring the current flowing in the first current path, and a plurality of second current sensors individually measuring the current flowing in each of the plurality of second current paths, and determining whether or not there is an abnormality in the connection circuit using the acquired measurement results of the first current sensor and the measurement results of the second current sensors.

[0031] According to the computer program of (9) above, even if the measured current value indicates an abnormal value, the cause can be determined, and it is possible to prevent the operation of the power storage facility from being stopped due to an erroneous decision.

[0032] The present invention will be described in detail below with reference to the drawings showing embodiments. (Embodiment 1) Fig. 1 is a schematic diagram showing the overall configuration of a power storage system including a storage battery facility (an example of a power storage facility). The power storage system according to the embodiment includes a storage battery facility 1, a power generation facility 2, and a load 3. The storage battery facility 1 is, for example, an ESS, and stores power supplied from the power generation facility 2 and supplies the stored power to the load 3. The power generation facility 2 includes a solar power generation facility 21, a wind power generation facility 22, or the like. The load 3 includes power consumption facilities such as factories, office buildings, schools, hospitals, restaurants, and airports.

[0033] A power converter 20 is installed between the storage battery equipment 1 and the power generation equipment 2 and load 3. The power converter 20 is also called a PCS (Power Conditioning System). The power converter 20 converts the power (AC power or DC power) supplied from the power generation equipment 2 into DC power of a predetermined magnitude and supplies the converted DC power to the storage battery equipment 1. The storage battery equipment 11 stores the power supplied from the power generation equipment 2 via the power converter 20.

[0034] In response to an external request, the storage battery equipment 11 supplies the stored power to the load 3. The power supplied from the storage battery equipment 11 to the load 3 is converted from DC power to AC power by a power converter 20.

[0035] Alternatively, the storage battery equipment 11 may store the power supplied from the power grid 4 and supply the stored power to the power grid 4 .

[0036] The power storage system includes a monitoring server 5 that remotely monitors the storage battery equipment 1. The storage battery equipment 1 and the monitoring server 5 are communicably connected via a communication network NW. The communication network NW may be a general line such as the Internet or a dedicated line. The storage battery equipment 1 transmits and receives information to and from the monitoring server 5 via the communication network NW.

[0037] Fig. 2 is a schematic diagram showing the internal configuration of the battery storage facility 1. The battery storage facility 1 includes a container body 10 (see Fig. 1), a battery panel 11, and a control panel 12 housed in the container body 10. Fig. 2 shows an example configuration of the battery panel 11 and the control panel 12 housed in the container body 10. The battery storage facility 1 may include two or more battery panels 11. In addition to the battery panel 11 and the control panel 12, the container body 10 may also house auxiliary equipment such as an air conditioner and lighting devices.

[0038] The battery panel 11 includes a plurality of banks 111 and a management unit 112. Each bank 111 is configured by electrically connecting a plurality of storage modules BT in series. In the example of FIG. 2 , the battery panel 11 includes three banks 111, and each bank 111 is configured by electrically connecting a total of 18 storage modules BT in series in two vertical columns. These three banks 111 are connected in parallel with each other. A configuration in which a plurality of banks 111 are connected in parallel is also called a domain. The number of banks 111 included in the battery panel 11 and the number of storage modules BT that make up each bank 111 can be selected arbitrarily.

[0039] The power storage module BT is configured by connecting multiple power storage cells in series. In one example, the power storage cells are battery cells based on lithium-ion secondary batteries. Alternatively, the power storage cells may be battery cells based on all-solid-state batteries, lead batteries, redox flow batteries, zinc-air batteries, alkaline manganese batteries, lithium-sulfur batteries, sodium-sulfur batteries, silver-zinc oxide batteries, nickel-metal hydride batteries, molten salt thermal batteries, or the like, or may be capacitors. The number of power storage cells constituting the power storage module BT can be selected arbitrarily.

[0040] The management unit 112 is a device for monitoring the status of the bank 111. A management unit 112 is provided for each bank 111. In the example of FIG. 2, a management unit 112 is provided above each bank 111. Hereinafter, the management unit 112 provided in the battery panel 11 will be referred to as a bank BMU (Battery Management Unit) 112. The bank BMU 112 monitors the status of the corresponding bank 111 and notifies the obtained information about the bank 111 to a higher-level management unit (domain BMU 121 shown in FIG. 3).

[0041] In the following, an example will be described in which the storage battery equipment 1 includes one storage battery panel 11, and the storage battery panel 11 includes three banks 111.

[0042] FIG. 3 is an explanatory diagram illustrating the circuit configuration of the storage battery equipment 1. As described above, the storage battery panel 11 of the storage battery equipment 1 includes three banks 111 and three bank BMUs 112 provided corresponding to each bank 111. The control panel 12 of the storage battery equipment 1 includes a domain BMU 121 and a communication interface 122. The bank BMUs 112 and the domain BMUs 121 are communicatively connected. An existing communication standard such as CAN (Controller Area Network) is used for communication between the bank BMUs 112 and the domain BMUs 121. Alternatively, communication standards such as LIN (Local Interconnect Network), ECHONET (registered trademark), and ECHONET Light (registered trademark) may be used.

[0043] The bank 111 is connected to an external current supply source or a current supply destination via a main circuit MC. The external current supply source is the power generation facility 2 (or the power grid 4), and the external current supply destination is the load 3 (or the power grid 4).

[0044] In the following description, when the three banks 111 are to be distinguished from one another, the banks 111 are also referred to as banks 111A, 111B, and 111C. Similarly, when the three bank BMUs 112 are to be distinguished from one another, the banks BMUs 112 are also referred to as banks BMUs 112A, 112B, and 112C.

[0045] The main circuit MC includes a first current path P1 connected to a current source or a current destination, and three second current paths P2A to P2C branching from the first current path P1 and connected to the banks 111A to 111C, respectively. The main circuit MC also includes a first current sensor S1 that measures the current flowing through the first current path P1, and three second current sensors S2A to S2C that measure the current flowing through each of the second current paths P2A to P2C. The first current sensor S1 and the second current sensors S2A to S2C are existing current sensors such as Hall sensors. The first current sensor S1 outputs its measurement results to the domain BMU 121. The second current sensors S2A to S2C output their measurement results to the domain BMU 121 via the respective bank BMUs 112A to 112C.

[0046] The domain BMU 121 is a device for monitoring the status of a domain (an entire bank). The domain BMU 121 includes, for example, a central processing unit (CPU), read-only memory (ROM), and random access memory (RAM). The CPU included in the domain BMU 121 reads and executes a computer program stored in the ROM, causing the domain BMU 121 to function as the determination device of the present application. The RAM temporarily stores data generated during execution of the computer program and data acquired from the outside.

[0047] In the embodiment, the domain BMU 121 acquires the measurement results of the first current sensor S1 and the measurement results of the second current sensors S2A to S2C, and determines whether or not there is an abnormality in the main circuit 120 using the acquired measurement results of the first current sensor S1 and the second current sensor S2.

[0048] The domain BMU 121 outputs the determination result of whether or not there is an abnormality in the main circuit 120. For example, the domain BMU 121 notifies an external device via the communication interface 122. An example of an external device is a monitoring server 5 that monitors the status of the storage battery equipment 1. The communication interface 122 of the storage battery equipment 1 and the monitoring server 5 are communicatively connected via a communication network NWA such as the Internet. If the storage battery equipment 1 has a display unit such as a liquid crystal display, the determination result of whether or not there is an abnormality in the main circuit 120 may be output to the display unit and displayed on the display unit.

[0049] FIG. 4 is a flowchart illustrating the processing steps executed by the storage battery equipment 1. When executing the following procedure, it is assumed that the internal resistance of each bank 111A to 111C has been measured in advance. The internal resistance is determined by actually measuring the voltage of each bank 111A to 111C when constant current discharge is performed from each bank 111A to 111C. The voltage of each bank 111A to 111C is measured using a voltage sensor (not shown). If the current value when constant current discharge is performed from bank 111A is I (I is known because constant current discharge is performed) and the voltage value of bank 111A is V (V is the actual value measured by the voltage sensor), the internal resistance R of bank 111A can be calculated using the formula R = V / I. The same applies to the internal resistances of the other banks 111B and 111C. It is assumed that the internal resistance values ​​of banks 111A, 111B, and 111C (represented as Ra, Rb, and Rc, respectively) are determined in advance and stored in memory within the domain BMU 121.

[0050] When power is supplied to the load 3, the storage battery equipment 1 measures the current flowing through the first current path P1 with the first current sensor S1, and measures the currents flowing through the second current paths P2A to P2C with the second current sensors S2A to S2C, respectively (step S101). The measurement result by the current sensor S1 is output to the domain BMU 121. The measurement results by the current sensors S2A to S2C are output to the bank BMUs 112A to 112C, respectively.

[0051] The domain BMU 121 acquires the measurement result of the first current sensor S1 and acquires the measurement results of the second current sensors S2A to S2C through the bank BMUs 112A to 112C (step S102). The current value obtained as the measurement result of the first current sensor S1 is I, and the current values ​​obtained as the measurement results of the second current sensors S2A, S2B, and S2C are Ia, Ib, and Ic, respectively.

[0052] The domain BMU 121 compares the current value measured by the first current sensor S1 with the sum of the current values ​​Ia to Ic measured by the second current sensors S2A to S2C and determines whether they are equal (step S103). That is, the domain BMU 121 determines whether I = Ia + Ib + Ic. The two values ​​do not need to be completely identical numerically; a deviation within the allowable error range is acceptable. In this case, if the allowable error is ε1, the two values ​​are determined to be substantially equal if the difference between them is less than ε1. The allowable error ε1 is set appropriately. For example, the allowable error ε1 may be set artificially. Alternatively, the difference in the current values ​​(= |I - (Ia + Ib + Ic)|) may be measured using a normal connection circuit MC, and the allowable error ε may be set based on that difference.

[0053] If it is determined that the total current values ​​are equal (S103: YES), the domain BMU 121 compares the ratio of the internal resistance values ​​of each bank 111A to 111C (= Ra:Rb:Rc) with the ratio of the current values ​​measured by the second current sensors S2A to S2C (= Ia:Ib:Ic) to determine whether the two are equal (step S104). That is, the domain BMU 121 determines whether Ra:Rb:Rc = Ia:Ib:Ic. The two do not need to be completely identical in numerical terms; values ​​may differ within the allowable error range. For example, if allowable errors ε2 and ε3 are defined as |Ia / Ra - Ib / Rb| < ε2 and |Ia / Ra - Ic / Rc| < ε3, the two are determined to be substantially equal. The allowable errors ε2 and ε3 are set appropriately. For example, ε2 and ε3 may be set artificially. Alternatively, the ratio (Ia:Ib:Ic) may be actually measured using a normal connection circuit MC, and the allowable errors ε2 and ε3 may be set based on the ratio.

[0054] If it is determined that the total current values ​​are equal (S103: YES) and the ratios are equal (S104: YES), the domain BMU 121 determines that the current paths (first current path P1 and second current paths P2A to P2C) and current sensors (first current sensor S1 and second current sensors S2A to S2C) in the connection circuit MC are normal (step S106).

[0055] If the total current values ​​are equal (S103: YES) but the ratios are different (S104: NO), the domain BMU 121 determines that the first current sensor S1 and the second current sensors S2A-S2C are normal and that one of the second current paths P2A-P2C has an abnormality (step S107). If the domain BMU 121 determines that one of the second current paths P2A-P2C has an abnormality, it may identify which current path has an abnormality. In this embodiment, because the ratio of the internal resistance values ​​is known, the domain BMU 121 can identify a path through which no current, expected from the ratio of the internal resistance values, is flowing as the path with an abnormality.

[0056] If it is determined in step S103 that the total current values ​​are different (S103: NO), the domain BMU 121 compares the ratio of the internal resistance values ​​of each bank 111A to 111C (= Ra:Rb:Rc) with the ratio of the current values ​​measured by the second current sensors S2A to S2C (= Ia:Ib:Ic) to determine whether the two are equal (step S105). The determination method is the same as in step S104, and the domain BMU 121 determines whether Ra:Rb:Rc = Ia:Ib:Ic. The two do not need to be numerically identical; the values ​​may differ within the allowable error range.

[0057] If the total current values ​​are different (S103: NO) and the ratios are determined to be equal (S105: YES), the domain BMU 121 determines that the first current sensor S1 is abnormal (step S108).

[0058] If it is determined that the total current values ​​are different (S103: NO) and the ratios are different (S105: NO), the domain BMU 121 determines that one of the second current sensors S2A to S2C is abnormal (step S109).

[0059] The domain BMU 121 outputs the determination results of S106 to S109 (step S110). For example, the domain BMU 121 notifies the monitoring server 5 of the determination results via the communication interface 122. If the control panel 12 is equipped with a display unit such as a liquid crystal display, the domain BMU 121 may display the determination results on the display unit.

[0060] As described above, in embodiment 1, by using the measurement results of the current flowing through the first current path P1 and the measurement results of the current flowing through each of the second current paths P2A to P2C, it is possible to determine whether there is an abnormality in the first current path P1, the second current paths P2A to P2C, the first current sensor S1, or the second current sensors S2A to S2C that make up the main circuit MC.

[0061] Second Embodiment In a second embodiment, a configuration for executing a determination process in a monitoring server 5 will be described. The overall configuration of the power storage system and the internal configuration of the storage battery equipment 1 are the same as those in the first embodiment, and therefore description thereof will be omitted.

[0062] 5 is a block diagram illustrating the internal configuration of the monitoring server 5. The monitoring server 5 includes a control unit 51, a storage unit 52, a communication unit 53, an operation unit 54, a display unit 55, and the like.

[0063] The control unit 51 is an arithmetic circuit including, for example, a CPU, a ROM, a RAM, etc. The CPU included in the control unit 51 reads and executes various computer programs stored in the ROM and the storage unit 52, causing the control unit 51 to function as a determination device that determines an abnormality in the main circuit MC in the storage battery equipment 1. In the embodiment, the control unit 51 determines an abnormality in the main circuit MC based on measurement results obtained from the storage battery equipment 1.

[0064] Alternatively, the control unit 51 may be any arithmetic circuit including multiple CPUs, a multi-core CPU, a GPU (Graphics Processing Unit), a microcomputer, a volatile or non-volatile memory, etc. The control unit 51 may also include functions such as a timer that measures the elapsed time from when an instruction to start measurement is given until when an instruction to end measurement is given, a counter that counts numbers, and a clock that outputs date and time information.

[0065] The memory unit 52 includes a storage device such as a flash memory or a hard disk. Various computer programs and data are stored in the memory unit 52. The computer programs stored in the memory unit 52 include a determination processing program PG for causing a computer to execute processing for determining an abnormality in the main circuit MC based on measurement results acquired from the storage battery equipment 1. The data stored in the memory unit 52 includes parameters used in the determination processing program PG, data generated by the control unit 51, and the like.

[0066] A computer program including the diagnostic program PG is provided by a non-transitory recording medium RM on which the computer program is readably recorded. The recording medium RM is a portable memory such as a CD-ROM, a USB memory, or an SD (Secure Digital) card. The control unit 51 reads the desired computer program from the recording medium RM using a reading device (not shown) and stores the read computer program in the memory unit 52. Alternatively, the computer program including the determination processing program PG may be provided via communication.

[0067] The communication unit 53 includes a communication interface for transmitting and receiving various types of information. The communication unit 53 receives, for example, the measurement results of the first current sensor S1 and the second current sensors S2A to S2C transmitted by the storage battery equipment 5.

[0068] The operation unit 54 is equipped with input devices such as various switches and buttons and accepts operations by the administrator. The display unit 55 is equipped with a display device such as a liquid crystal display and displays information to be notified to the administrator. Alternatively, the monitoring server 5 may be configured to accept necessary operations via an external computer and transmit information to be notified to the administrator to the external computer. In this case, the operation unit 54 and the display unit 55 do not need to be installed in the monitoring server 5.

[0069] In the embodiment, the monitoring server 5 may be a single computer, or may be a computer system configured with multiple computers and peripheral devices, etc. The monitoring server 5 may be a virtual machine whose entity is virtualized, or may be a cloud.

[0070] In the embodiment, the determination processing program PG may be a single computer program or a program group consisting of multiple computer programs. The determination processing program PG may be executed by multiple computers working together.

[0071] 6 is a flowchart illustrating the procedure of processing executed by the monitoring server 5. In executing the following procedure, it is assumed that the internal resistance of each of the banks 111A to 111C has been measured in advance, and each measured value has been stored in the storage unit 52 of the monitoring server 5.

[0072] The control unit 51 of the monitoring server 5 acquires the measurement results of the first current sensor S1 and the measurement results of the second current sensors S2A to S2C from the storage battery equipment 1 via the communication unit 53 (step S201).

[0073] The control unit 51 uses the acquired measurement results to determine whether there is an abnormality in the main circuit MC. The determination procedure is the same as in the first embodiment. The control unit 51 compares the current value measured by the first current sensor S1 with the total value of the currents measured by the second current sensors S2A to S2C and determines whether they are equal (step S202). The control unit 51 compares the ratio of the internal resistance values ​​of each bank 111A to 111C with the ratio of the current values ​​measured by the second current sensors S2A to S2C and determines whether they are equal (steps S203 and S204).

[0074] If it is determined that the total values ​​are equal and the ratios are equal (S202: YES, S203: YES), the control unit 51 determines that the main circuit MC is normal (step S205).

[0075] If it is determined that the total values ​​are equal and the ratios are different (S202: YES, S203: NO), the control unit 51 determines that an abnormality exists in one of the second current paths P2A to P2C (step S206).

[0076] If it is determined that the total values ​​are different and the ratios are equal (S202: NO, S204: YES), the control unit 51 determines that there is an abnormality in the first current sensor S1 (step S207).

[0077] If the total values ​​and ratios are different (S202: NO, S204: NO), the control unit 51 determines that one of the second current sensors S2A to S2C is abnormal (step S208).

[0078] The control unit 51 outputs the determination results of S205 to S208 (step S209). For example, the control unit 51 may display the determination results on the display unit 55. Alternatively, the control unit 51 may notify the determination results to a terminal of an administrator or the like via the communication unit 53.

[0079] As described above, in embodiment 2, the external monitoring server 5 can determine whether there is an abnormality in the first current path P1, the second current paths P2A to P2C, the first current sensor S1, or the second current sensors S2A to S2C that constitute the main circuit MC of the storage battery equipment 1.

[0080] The disclosed embodiments are illustrative in all respects and are not restrictive. The scope of the present invention is defined by the claims, and includes all modifications within the meaning and scope of the claims.

[0081] For example, in the embodiment, the storage battery equipment 1 is configured to include one storage battery panel 11, and this storage battery panel 11 is configured to include three banks 111. Alternatively, the storage battery equipment 1 may be configured to include multiple storage battery panels 11, and each storage battery panel may be configured to include one or more banks 111.

[0082] In the embodiment, the power converter 20 is provided separately from the storage battery equipment 1. Alternatively, the storage battery equipment 1 may be provided with the power converter 20.

[0083] REFERENCE SIGNS LIST 1 Battery equipment (power storage equipment) 2 Power generation equipment 3 Load 4 Power system 5 Monitoring server 11 Battery panel 12 Control panel 111 Bank 112 Bank BMU 121 Domain BMU 122 Communication interface MC Connection circuit P1 First current path P2A to P2C Second current path S1 First current sensor S2A to S2C Second current sensor

Claims

1. A power storage facility comprising a plurality of energy storage elements connected in parallel, and a connection circuit connecting the plurality of energy storage elements to an external current supply source or current supply destination, wherein the connection circuit includes: a first current path connected to the current supply source or the current supply destination; a plurality of second current paths branching from the first current path and connected to the plurality of energy storage elements, respectively; a first current sensor measuring a current flowing through the first current path; and a plurality of second current sensors measuring individually the current flowing through each of the plurality of second current paths; and a determination unit determining the presence or absence of an abnormality in the connection circuit using the measurement results of the first current sensor and the measurement results of the plurality of second current sensors.

2. The energy storage facility according to claim 1, wherein the determination unit compares a current value indicating the magnitude of the current measured by the first current sensor with a total value indicating the sum of the magnitudes of the individual currents measured by the multiple second current sensors, compares a ratio of the individual internal resistance values ​​of the multiple energy storage elements with a ratio of the individual current magnitudes measured by the multiple second current sensors, and determines the presence or absence of an abnormality in the connection circuit depending on the comparison result between the current value and the total value and the comparison result between the ratio of the internal resistance values ​​and the ratio of the current magnitudes.

3. The energy storage facility according to claim 2, wherein the determination unit determines that there is an abnormality in the first current sensor when the current value and the total value differ and the ratio of the internal resistance values ​​and the ratio of the current magnitudes are substantially equal.

4. The energy storage facility according to claim 2, wherein the determination unit determines that there is an abnormality in at least one of the second current sensors when the current value and the total value differ and when the ratio of the internal resistance values ​​and the ratio of the current magnitudes differ.

5. The energy storage facility according to claim 2, wherein the determination unit determines that there is an abnormality in at least one of the second current paths when the current value and the total value are substantially equal and the ratio of the internal resistance values ​​and the ratio of the current magnitudes differ.

6. The energy storage facility according to claim 2, wherein the determination unit determines that there is no abnormality in the connection circuit when the current value and the total value are substantially equal and the ratio of the internal resistance values ​​and the ratio of the current magnitudes are substantially equal.

7. The energy storage facility according to any one of claims 1 to 6, wherein the energy storage element is a module formed by connecting a plurality of energy storage cells in series, or a bank formed by connecting a plurality of such modules in series.

8. The power storage facility according to any one of claims 1 to 7, further comprising a display unit that displays a determination result from the determination unit.

9. The energy storage facility according to any one of claims 1 to 7, further comprising a communication unit that notifies a manager or the like of the determination result from the determination unit.

10. A determination device comprising: an acquisition unit that acquires measurement results of the first current sensor and measurement results of the multiple second current sensors from an energy storage facility including a plurality of energy storage elements connected in parallel, a first current path connected to an external current source or current destination, a plurality of second current paths branching off from the first current path and connected to each of the plurality of energy storage elements, a first current sensor that measures a current flowing through the first current path, and a connection circuit including a plurality of second current sensors that individually measure a current flowing through each of the plurality of second current paths; and a determination unit that determines the presence or absence of an abnormality in the connection circuit using the acquired measurement results of the first current sensor and the measurement results of the multiple second current sensors.

11. A computer program for causing a computer to execute a process of acquiring measurement results of the first current sensor and the multiple second current sensors from an energy storage facility including a plurality of energy storage elements connected in parallel, a first current path connected to an external current source or a current destination, a plurality of second current paths branching off from the first current path and connected to the plurality of energy storage elements, a first current sensor measuring a current flowing through the first current path, and a connection circuit including a plurality of second current sensors measuring the current flowing through each of the multiple second current paths, and determining the presence or absence of an abnormality in the connection circuit using the acquired measurement results of the first current sensor and the measurement results of the multiple second current sensors.

12. A method for determining whether or not there is an abnormality in an electrical storage facility including a first current path connected to an external current source or a current destination, a first current path connected to an external current source or a current destination, a first current path connected to each of the first current paths, a first current sensor measuring a current flowing in the first current path, and a connection circuit including a first current sensor and a second current sensor measuring a current flowing in each of the second current paths, the method comprising: acquiring a measurement result of the first current sensor and a measurement result of the second current sensors from the electrical storage facility; and determining whether or not there is an abnormality in the connection circuit using the acquired measurement result of the first current sensor and the measurement results of the second current sensors.

13. A method for determining whether or not there is an abnormality in an electrical storage device, the method comprising: acquiring measurement results of the first current sensor and measurement results of the second current sensors from an electrical storage device including a plurality of electrical storage elements connected in parallel; a first current path connected to an external current source or a current destination; a plurality of second current paths branching off from the first current path and connected to each of the plurality of electrical storage elements; a first current sensor measuring a current flowing in the first current path; and a connection circuit including a plurality of second current sensors measuring individually a current flowing in each of the plurality of second current paths; determining whether or not there is an abnormality in the connection circuit using the acquired measurement results of the first current sensor and the acquired measurement results of the plurality of second current sensors; and displaying the determination result.

14. A method for determining whether or not there is an abnormality in the connection circuit from an energy storage facility including a plurality of energy storage elements connected in parallel, a first current path connected to an external current source or a current destination, a plurality of second current paths branching off from the first current path and connected to each of the plurality of energy storage elements, a first current sensor measuring the current flowing in the first current path, and a connection circuit including a plurality of second current sensors measuring the current flowing in each of the plurality of second current paths individually, the method comprising: acquiring a measurement result of the first current sensor and a measurement result of the plurality of second current sensors; determining whether or not there is an abnormality in the connection circuit using the acquired measurement result of the first current sensor and the measurement results of the plurality of second current sensors; and notifying a terminal of an administrator or the like of the determination result.

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