JPWO2017163990A1 - Monitoring device, monitoring system, and monitoring method - Google Patents

Abstract

  The monitoring device 100 is a monitoring device that monitors the state of the plurality of battery cells 11 in order to detect the occurrence of liquid leakage while suppressing the enlargement of the device and the complication of the configuration, and the battery after the discharge is completed. Using a first condition based on the voltage difference between the cells 11, a leakage detector 102 that detects the occurrence of leakage from the voltage of each battery cell 11 is provided.

Description

  The present invention relates to a monitoring device, a monitoring system, and a monitoring method for monitoring battery leakage.

  In recent years, secondary batteries that can be repeatedly charged and discharged have been used in a wide range of applications. Some power storage systems using secondary batteries constitute a monitoring system that detects aging of secondary batteries and abnormalities in the system. When the monitoring system detects an abnormality, a maintenance staff is dispatched to the site where the abnormality has occurred to perform maintenance work such as replacement or repair of parts. One of the abnormalities that occur in the power storage system is a leakage of a secondary battery. Some secondary batteries have electrodes and electrolytes sealed inside the exterior body, and when the exterior body is damaged, leakage occurs in which the electrolyte solution leaks out of the exterior body. When a liquid leak occurs, the maintenance procedure and tools necessary for the maintenance work are different from those when other abnormalities occur. Therefore, it is preferable to detect the abnormality due to the liquid leakage separately from the other abnormality.

  Patent Document 1 discloses a liquid leakage detection device including a sensor that detects that an electrolytic solution has adhered in order to detect leakage. This liquid leak detection device detects a change in resistance of the sensor caused by the electrolytic solution adhering to the sensor surface as the occurrence of liquid leak.

Japanese Patent Laying-Open No. 2005-238881 JP 2005-235420 A

  However, the liquid leak detection device described in Patent Document 1 needs to be provided with a sensor in addition to the configuration of the conventional secondary battery, and the size is increased by the space for installing the sensor, the cost is increased, and the configuration is increased. There was a problem of becoming complicated.

  Therefore, an object of the present invention is to provide a monitoring device, a monitoring system, and a monitoring method that solve the above-described problems.

The monitoring device according to the present invention comprises:
A monitoring device for monitoring the state of a plurality of battery cells,
A liquid leakage detection unit that detects the occurrence of liquid leakage from the voltage of each battery cell using a first condition based on the voltage difference between the battery cells after completion of discharge is provided.

The monitoring system according to the present invention comprises:
A plurality of battery cells;
A voltage detector for detecting a voltage value of each of the plurality of battery cells;
A monitoring device that monitors the state of the plurality of battery cells based on the voltage value;
The monitoring device includes a liquid leakage detection unit that detects the occurrence of liquid leakage using a first condition based on a voltage difference between battery cells after completion of discharge.

The monitoring method according to the present invention comprises:
A monitoring method for monitoring a state of a plurality of battery cells,
Obtaining a voltage difference between the battery cells of the plurality of battery cells after completion of discharge;
Detecting occurrence of liquid leakage using a first condition based on the voltage difference.

  According to the present invention, it is possible to detect the occurrence of liquid leakage while suppressing the enlargement of the apparatus and the complexity of the configuration.

It is a figure which shows the function structure of the monitoring system which concerns on the 1st Embodiment of this invention. It is a function block diagram of the monitoring apparatus 100 of FIG. It is a graph which shows the characteristic of the deterioration degree of the battery cell which leaked. It is a graph which shows the characteristic of the voltage difference between the cells of the leaked battery cell. It is a graph which shows the characteristic of the fall amount of the cell voltage of the battery cell which leaked. 3 is a flowchart for explaining an operation example of the monitoring apparatus 100 of FIG. 1. It is a functional block diagram of the monitoring apparatus 200 which concerns on the 2nd Embodiment of this invention. It is a flowchart for demonstrating the operation example of the monitoring apparatus 200 of FIG. It is a figure for demonstrating determination of a leak level. It is a functional block diagram of the monitoring apparatus 300 which concerns on the 3rd Embodiment of this invention. It is a flowchart for demonstrating the operation example of the monitoring apparatus 300 of FIG. It is a figure which shows the hardware structural example of a monitoring system.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In addition, in this specification and drawing, the description which overlaps may be abbreviate | omitted by attaching | subjecting the same code | symbol about the component which has the same function.

<First Embodiment>
(Functional configuration of the monitoring system)
FIG. 1 is a diagram showing a functional configuration of a monitoring system according to the first embodiment of the present invention. The monitoring system includes a battery group 10 including a plurality of battery cells 11, a voltage detection unit 20 that detects a voltage value of each battery cell 11, and a monitoring device 100 that monitors the state of the battery group 10.

  The battery group 10 includes a plurality of battery cells 11. The battery group 10 may have a battery module in which a plurality of battery cells 11 are stored in a housing. The battery cell 11 is a secondary battery that can be repeatedly charged and discharged. The battery cell 11 may be a lithium ion secondary battery, for example. Although not shown, each battery cell 11 includes an exterior body, an electrode and an electrolytic solution stored in the exterior body.

  Each of the battery cells 11 and the voltage detection unit 20 are connected by a voltage detection line. Although one voltage detection unit 20 is shown in FIG. 1, a plurality of voltage detection units 20 may be provided for each battery cell 11, or a plurality of battery cells 11 and a unit as one unit. May be provided. The voltage detector 20 can detect the voltage value of each battery cell 11. The voltage detector 20 and the monitoring device 100 are connected by a communication line or the like. The voltage detection unit 20 notifies the monitoring device 100 of the detected voltage value. The monitoring device 100 can receive the voltage value from the voltage detection unit 20 and determine the state of the battery cell 11 based on the received voltage value.

  Although not shown, the battery group 10 is connected to a load that is driven by using the electric power stored in the battery group 10 and a charge / discharge control unit that controls charging and discharging of the battery group 10. Is configured. The monitoring device 100 monitors the state of this power storage system.

(Functional configuration of monitoring device 100)
FIG. 2 is a diagram illustrating a functional configuration of the monitoring apparatus 100 of FIG. The monitoring device 100 includes a battery state acquisition unit 101, a liquid leakage detection unit 102, and a notification unit 103. The battery state acquisition unit 101 acquires information indicating the state of the battery group 10. The battery state acquisition unit 101 acquires, for example, the voltage value of each battery cell 11 detected by the voltage detection unit 20. The battery state acquisition unit 101 can also acquire information indicating whether the battery group 10 is in a charged state, in a discharged state, or neither.

  The leak detection unit 102 can detect the leak of the battery cell 11 based on the information acquired by the battery state acquisition unit 101. The liquid leakage detection unit 102 can detect the occurrence of liquid leakage from information indicating the state of the battery cell 11 without using a sensor or the like that detects the liquid in contact with the detection surface.

  The notification unit 103 notifies the occurrence of liquid leakage when the liquid leakage detection unit 102 detects the occurrence of liquid leakage. Various forms of the notification destination and the notification method can be considered according to the configuration of the monitoring system. For example, the notification destination may be a user of the power storage system or a management business operator that manages a plurality of power storage systems. The notification method may be, for example, a notification method using an image or light, or a notification method using sound.

(Characteristics of battery cell where leakage occurred)
3-5 is a figure for demonstrating the characteristic which appears in the state of the battery cell in which the liquid leak generate | occur | produced. Specifically, FIG. 3 is a graph showing the relationship between the number of battery cell cycles and SOH (State Of Health). FIG. 4 is a graph showing changes in cell voltage over time. FIG. 5 is a graph showing the relationship between the elapsed time after completion of charging and the amount of decrease in cell voltage for each battery cell.

  FIG. 3 shows the number of cycles and SOH for a standard battery cell in which no leakage occurs (hereinafter referred to as a standard cell) and a battery cell in which leakage occurs (hereinafter referred to as a leakage cell). The relationship is shown. In contrast to the standard cell, the SOH gradually decreases as the number of cycles increases, whereas in the leak cell, the SOH decreases gradually as the number of cycles increases until the specific number of cycles s1, If it exceeds s1, the amount of decrease in SOH suddenly increases. In the battery cell 11, an electrode and an electrolytic solution are enclosed in an exterior body. The electrolyte is sealed in a larger amount than necessary for charging / discharging, and when there is no leakage, between the electrodes and around the stack of electrodes Exists. When the exterior body is damaged, the electrolyte leaks out of the exterior body. In the initial state where the liquid leakage occurs, the surplus amount of the electrolytic solution leaks out of the exterior body, so that the battery capacity is less affected. Therefore, up to the number of cycles s1 in FIG. 3, it is considered that the surplus of the electrolyte has leaked out and is in the initial state of the leak. Thereafter, when the leakage proceeds and the electrolyte used for charging and discharging the battery is insufficient, the SOH rapidly decreases. As the leakage progresses, the battery capacity is greatly affected, and the electrolyte solution may touch other parts such as the battery cells installed around the leaking battery cell, requiring replacement. is there. For this reason, when liquid leakage occurs, it is preferable to detect it at the earliest possible stage.

  FIG. 4 shows a maximum cell voltage that is a voltage value of a high voltage cell having the highest cell voltage, a minimum cell voltage that is a voltage value of a low voltage cell having the lowest cell voltage, and a voltage difference ΔV ( (Maximum cell voltage−minimum cell voltage). In this power storage system, charging is performed by the CCCV method, and after charging with a constant current until the voltage of the battery group 10 reaches a predetermined voltage, when the predetermined voltage is reached, the current value is reduced to a constant voltage. Charging is performed (CCCV: Constant Current Constant Voltage). The discharge completion condition is any of the conditions in which the battery group 10 reaches a predetermined voltage, any one of the battery cells 11 reaches a predetermined voltage, or the accumulated discharge capacity reaches a predetermined value. The inventors of the present invention have found that the voltage difference between the battery cells after the completion of the discharge becomes large when a leakage occurs. In this example, the voltage difference between the highest cell voltage and the lowest cell voltage increases toward the time points T1 and T2 when the discharge is completed. For this reason, the voltage difference between the battery cells after completion of discharge is large. This seems to be because the capacity of the cell in which the liquid leakage occurred is decreasing.

  FIG. 5 shows the elapsed time after the completion of charging and the amount of decrease in cell voltage for the three battery cells 11. In FIG. 5, the voltage drop amount is expressed as a negative value. The cell 01 is a standard battery cell 11 in which no leakage occurs. Cell 02 and cell 03 are battery cells 11 in which liquid leakage occurs. The cell 03 has a larger amount of electrolyte leaked than the cell 02, and the leakage is progressing. The inventors of the present invention have found that when a leakage occurs, a change in cell voltage with time in a state in which neither charging nor discharging after completion of charging is performed becomes large. In this example, the voltage drop amount of the cell 02 and the cell 03 is larger than that of the cell 01. Further, it can be seen that the amount of voltage drop in the cell 03 where the liquid leakage is more advanced is large. In this tendency, the vicinity of the leaked portion where the leak is occurring is altered and the resistance is large, so that the voltage distribution in the battery becomes non-uniform. It is considered that the voltage was large when the current was flowing, but the voltage was made uniform in the battery cell and the voltage drop was increased if the current was not flowing.

(Leakage detection operation example)
FIG. 6 is a flowchart for explaining an example of an operation in which the monitoring apparatus 100 according to the first embodiment of the present invention determines whether or not liquid leakage has occurred.

  First, the monitoring device 100 determines the first condition based on the voltage difference between the battery cells after completion of the discharge. Specifically, the battery state acquisition unit 101 acquires a voltage difference between cells after completion of discharge. At this time, the battery state acquisition unit 101 acquires the voltage values after completion of the discharge of all the battery cells 11 to be monitored by the monitoring system, records them in a storage unit (not shown), and for all combinations, between the cells. Get the voltage difference. Or it is good also considering the difference of the voltage value of each battery cell 11 and the average value of the voltage value of several other battery cell 11 as a voltage difference between cells (step S101).

  When the liquid leakage detection unit 102 receives a voltage difference between cells after completion of discharge from the battery state acquisition unit 101, the leakage detection unit 102 determines whether each voltage difference is larger than a predetermined first condition threshold value. The first condition threshold value can be set to 600 mV, for example, when the lithium ion battery is discharged at a rate of about 0.3 C (step S102).

When at least one of the plurality of voltage differences has a voltage difference larger than the first condition threshold, the liquid leakage detection unit 102 determines that the first condition is satisfied. Subsequently, the battery state acquisition unit 101 analyzes the amount of decrease in the cell voltage with time after completion of charging, which has already been acquired and has been charged immediately before. For example, the battery state acquisition unit 101 acquires the cell voltage of each of the battery cells 11 at a predetermined time interval from the time when charging is completed, and calculates the amount of decrease. At this time, the battery state acquisition unit 101 may acquire the decrease amount of the cell voltage after completion of charging for all the battery cells 11.
Or the battery state acquisition part 101 may acquire the fall amount of the cell voltage of the battery cell 11 used in order to calculate the said voltage difference about the voltage difference larger than a 1st condition threshold value (step S103).

  The liquid leakage detection unit 102 determines whether or not the amount of decrease in the cell voltage after completion of charging is greater than the second condition threshold value. The second condition threshold can be set to −15 mV, for example, 4 hours after the completion of charging (step S104).

  The leak detection unit 102 determines that the second condition is satisfied when the amount of time-dependent decrease in the cell voltage after completion of charging is greater than the second condition threshold, and the battery cell 11 has leaked. It determines with having generate | occur | produced (step S105).

  If the voltage difference is equal to or smaller than the first condition threshold value in step S102, and if the cell voltage decrease amount is equal to or smaller than the second condition threshold value in step S104, the liquid leakage detection unit 102 has no liquid leakage. And another abnormality determination is executed (step S106).

(Modification)
In the above example, the battery state acquisition unit 101 records the voltage values for all the battery cells 11, but the battery state acquisition unit 101 determines the voltages of the plurality of battery cells 11 in order to suppress the storage capacity. Of the values, only the highest voltage value and the lowest voltage value may be stored. Since the battery cell 11 in which liquid leakage has occurred often exhibits the lowest voltage value or the highest voltage value, it is possible to detect the liquid leakage even in this case. When the battery state acquisition unit 101 acquires only the highest voltage value and the lowest voltage value, the liquid leakage detection unit 102 determines in step S102 the voltage difference between the highest voltage value and the lowest voltage value, and the first condition. Compare with the threshold. In this case, in step S104, the leak detection unit 102 compares the amount of decrease with time of the highest voltage value and the amount of decrease with time of the lowest voltage value with the second condition threshold value.

  The leak detection unit 102 can use values suitable for detecting leak as the first condition threshold and the second condition threshold. These values may be predetermined values based on, for example, experiments. Further, the amount of decrease in cell voltage with time after completion of charging varies depending on the degree of deterioration of the battery cell 11, and the battery cell 11 having a high degree of deterioration is a battery having a low degree of deterioration even when no leakage occurs. Compared with the cell 11, the amount of decrease tends to increase. For this reason, the leak detection part 102 can use the value according to the deterioration degree of each battery cell 11 as a 2nd condition threshold value.

  Moreover, in the charge / discharge control part which controls charge and discharge of the battery group 10, the cell balance operation | movement which controls charging / discharging so that the voltage difference between the battery cells 11 becomes small is performed. For example, in the case where the cell balance operation is set to be executed when the voltage difference between the battery cells 11 is equal to or greater than a predetermined threshold, the first condition threshold is used to determine the execution of the cell balance operation. It can also be set to the same value as the threshold value. In this case, the liquid leakage detection unit 102 can detect the occurrence of liquid leakage based on the presence / absence and execution frequency of the cell balance operation.

(effect)
As described above, according to the first embodiment of the present invention, it is possible to detect liquid leakage from the characteristics of the battery cell 11 without adding a special component such as a sensor that detects that the electrolytic solution has been touched. Can do. For this reason, the space required when providing a sensor is unnecessary, and in the monitoring apparatus 100, the enlargement of the battery group 10, an increase in cost, and the complexity of a structure can be suppressed. In addition, when a leak is detected using a sensor, the sensor may not be provided depending on the structure of the battery group 10. However, in this embodiment, the sensor is not necessary and the leak is not dependent on the configuration of the battery group 10. Can be detected. In addition, when detecting a leak using a sensor, the state in which the electrolyte is attached to the sensor is considered to be a state in which the degree of the leak has increased. In this embodiment, when the voltage difference between cells after completion of discharge or the amount of decrease in cell voltage after completion of charging occurs to the extent that a change that can be determined as leakage occurs, the leakage level is usually the amount of electrolyte attached to the sensor. In many cases, the initial stage is more than the level of leakage. Therefore, according to this embodiment, it is possible to detect liquid leakage at an earlier stage than using the sensor. In addition, when a sensor is used, even if liquid leakage actually occurs, the liquid leakage cannot be detected if the electrolytic solution does not adhere to the sensor. On the other hand, in the present embodiment, it is possible to detect the leaked liquid wherever the electrolytic solution leaked from the exterior body flows out.

  In addition, when an abnormality due to leakage occurs, the tools required by maintenance personnel to replace or collect the battery cells in order to deal with the leaked electrolyte are different from those of other abnormalities. For this reason, since it is possible to detect the occurrence of liquid leakage before going to the site where the battery cell 11 is installed, it becomes possible for maintenance personnel to prepare tools for coping with the liquid leakage in advance, and for maintenance. The work efficiency can be improved.

<Second Embodiment>
(Functional configuration of monitoring device 200)
The monitoring system according to the second embodiment of the present invention is configured to include a monitoring device 200 instead of the monitoring device 100 in the first embodiment shown in FIG. FIG. 7 is a diagram illustrating a functional configuration of the monitoring apparatus 200 according to the second embodiment of the present invention. The monitoring device 200 includes a battery state acquisition unit 101, a leak detection unit 102, a notification unit 203, and a leak level determination unit 204. That is, the monitoring device 200 includes a notification unit 203 instead of the notification unit 103 of the monitoring device 100, and further includes a liquid leakage level determination unit 204.

  When the leak detection unit 102 detects the occurrence of a leak, the leak level determination unit 204 determines the level of the leak. Specifically, the liquid leakage level determination unit 204 determines the level of liquid leakage based on the ratio at which the voltage value of the specific battery cell 11 is the lowest among the plurality of battery cells 11 in a predetermined period. Can do. Moreover, the leak level determination part 204 may determine the level of leak based on the execution frequency of the cell balance operation | movement which makes the voltage difference between battery cells small.

  The notification unit 203 can notify the level of leakage in addition to the function of notifying the occurrence of leakage of the notification unit 103. The notification method may be a notification method using, for example, an image or light, or may be a notification method using sound.

(Operation example of the monitoring device 200)
FIG. 8 is a flowchart for explaining an operation example of the monitoring apparatus 200. The monitoring device 200 first performs a leakage determination (step S200). This leakage determination corresponds to steps S101 to S105 in FIG. Subsequently, the leakage level determination unit 204 determines whether or not the leakage detection unit 102 has detected leakage (step S201).

  When the liquid leakage is detected, the liquid leakage level determination unit 204 determines the liquid leakage level (step S202).

  Specifically, the leakage level determination unit can determine the leakage level based on a ratio at which the voltage value of the specific battery cell 11 is the lowest among the plurality of battery cells 11 in a predetermined period. it can. FIG. 9 is a diagram for explaining an example of a method for determining a leakage level. FIG. 9 shows the number of the low-pressure cell that is the battery cell having the lowest voltage value among the plurality of battery cells 11 at the ten time points. In addition, 10 time points are sampled at regular time intervals in the time from the start to the completion of discharge. Of the ten time points, the low-pressure cell number is “13” at eight time points, the low-pressure cell number is “1” at one time point, and the low-pressure cell number is “5” at one time point. It is. In this case, among the plurality of battery cells 11, the ratio at which the voltage value of the specific battery cell 11 having the cell number “13” is lowest is 80%. The leak level determination unit 204 determines the leak level using a threshold for this ratio. For example, when the ratio at which the voltage value of a specific battery cell 11 is the lowest is 80% or more, the liquid leakage level determination unit 204 determines that the liquid leakage level is high and is a serious liquid leakage, and is less than 80%. It can be determined that the leakage level is low and the leakage is slight. Alternatively, the liquid leakage level determination unit 204 may determine the liquid leakage level based on the execution frequency of the cell balance operation. In addition, cell balance operation | movement reduces a voltage difference, when the voltage difference of the some battery cell 11 becomes more than predetermined value. The leakage level determination unit 204 can determine that the leakage level is higher as the execution frequency of the cell balance operation is higher. Furthermore, the liquid leakage level determination unit 204 determines the liquid leakage level based on both the ratio at which the voltage value of the specific battery cell 11 is the lowest among the plurality of battery cells 11 and the execution frequency of the cell balance operation. You can also.

  Returning to the description of FIG. When the leakage level determination unit 204 determines the leakage level, the determination result is input to the notification unit 203, and the notification unit 203 notifies the occurrence of leakage and the leakage level (step S203).

(Modification)
In the above, the leak level determination unit 204 uses one threshold value to determine whether the leak level is a serious leak with a leak level higher than a predetermined standard or a minor leak with a low leak level. However, the present invention is not limited to such an example. The leak level may be indicated by a numerical value corresponding to the level, or may be indicated in a plurality of stages using a plurality of threshold values.

(effect)
As described above, according to the second embodiment of the present invention, when a leak is detected, the level of the leak can be detected. Depending on the level of leakage, the parts that need to be replaced and the tools needed for repair may vary. For example, in the case of a severe leak with a high leak level, the liquid may adhere to the container storing the battery group 10 and the container may be rusted if it is made of metal. It is necessary to prepare. For this reason, since the level of the liquid leakage can be known before going to the site where the battery cell 11 is installed, it becomes possible to examine a tool that maintenance personnel bring for repair or replacement.

<Third Embodiment>
(Functional configuration of monitoring device 300)
FIG. 10 is a diagram illustrating a functional configuration of the monitoring apparatus 300 according to the third embodiment of the present invention.

  The monitoring device 300 monitors the state of the plurality of battery cells 11 and uses the first condition based on the voltage difference between the battery cells 11 after the discharge is completed to generate leakage from the voltage of each battery cell 11. A liquid leakage detection unit 102 for detection is provided.

(Operation example of the monitoring device 300)
FIG. 11 is a flowchart for explaining an operation example of the monitoring apparatus 300. The liquid leakage detection unit 102 detects the occurrence of liquid leakage using the first condition.

  The monitoring device 300 detects the occurrence of liquid leakage using the first condition when the SOH value of the specific battery cell 11 is greatly deviated from the estimated SOH value according to the usage period. Is possible. The estimated SOH value varies depending on the usage environment of the power storage system or the characteristics of the battery cell itself. For this reason, when the difference between the actual value of SOH and the estimated value for each battery cell 11 is equal to or greater than a predetermined threshold value (degradation degree threshold value), the monitoring device 300 uses the first condition to leak liquid. You may detect generation | occurrence | production of.

(effect)
As described above, according to the third embodiment of the present invention, it is possible to detect the occurrence of liquid leakage while suppressing the enlargement of the apparatus and the complexity of the configuration.

(Hardware configuration example)
The monitoring system of the present invention described using the first to third embodiments can be applied to various power storage systems including battery cells. For example, the monitoring system can be applied to a power storage system including a storage battery that stores power used in each home.

  FIG. 12 is a configuration diagram illustrating an example of a hardware configuration of a power storage system 400 to which the monitoring system according to the first to third embodiments of the present invention is applicable.

  The power storage system 400 includes a storage battery 401, a HEMS (Home Energy Management System) 402, a smart meter 403, a monitor 404, a distribution board 405, an electric load 406, a power generation device 407, and an electric vehicle 408. . The power storage system 400 is connected to the Internet 600 and a power transmission network 500 owned by a power company.

  Storage battery 401 includes a secondary battery that can be repeatedly charged and discharged, such as a battery cell. The storage battery 401 can store electricity generated by the power generation device 407 and electricity supplied from a commercial power source (not shown), and can supply the stored electricity to the electrical load 406 and the like.

  The HEMS 402 is a control device that grasps the usage status of energy and controls and manages the power storage system 400 so that it can be efficiently operated as a whole. The HEMS 402 can be connected to, for example, a server 601 on the Internet 600, and can report the usage status of energy in the power storage system 400 to the server 601 or operate in accordance with an instruction from the server 401. Further, the HEMS 402 is connected to the storage battery 401, the electric load 406, and the like through a communication path, and can control the operation of the storage battery 401, the electric load 406, and the like. The HEMS 402 can notify the use status of energy in the power storage system 400 and an abnormality occurring in the power storage system 400 using the monitor 404.

  The storage battery 401, smart meter 403, electric load 406, power generator 407, electric vehicle 408, and the like are connected via a distribution board 405. Thereby, electricity sent from the power transmission network 500 via the smart meter 403 or electricity generated by the power generation device 407 is supplied to the electric load 406 or the storage battery 401 or stored in the storage battery 401 or the electric vehicle 408. Electricity is supplied to the electric load 406.

  The smart meter 403 is a power meter having a communication function. By connecting the smart meter 403 to the HEMS 402, it becomes possible to grasp the usage status of electricity in both the power storage system 400 and the power company.

  The monitor 404 is connected to the HEMS 402 and is an example of an output device that outputs information related to the power storage system 400 such as electricity usage status. The monitor 404 may be a dedicated monitor for the power storage system 400, or may be a device such as a personal computer (PC), a television receiver, a smartphone, or a tablet terminal.

  The electric load 406 is a device that consumes electric power in the power storage system 400, and is, for example, a television receiver, a PC, an air conditioner, a lighting fixture, or the like.

  The power generation device 407 is a solar power generation device, for example, and generates electricity from an energy source such as sunlight. Electricity generated by the power generation device 407 is stored in the storage battery 401 and the electric vehicle 408, or sold to a power company.

  The electric vehicle 408 is a vehicle including a battery cell, and can be used as a storage battery by being connected to the power storage system 400. The electric vehicle 408 can supply the stored electricity to the electric load 406 when the amount of electricity used is large or during a power failure.

(Correspondence relationship between monitoring system functional configuration and hardware configuration)
An example of a correspondence relationship between the functional configuration of the monitoring system illustrated in FIG. 1 and the hardware configuration illustrated in FIG. 12 will be described. When the monitoring system illustrated in FIG. 1 is applied to the power storage system 400 in FIG. 12, the battery group 10 is, for example, a secondary battery provided in the storage battery 401 or the electric vehicle 408. When the battery group 10 is a secondary battery provided in the storage battery 401, the voltage detection unit 20 may also be provided in a housing in which the secondary battery of the storage battery 401 is stored. In this case, the monitoring device 100 may be provided in the HEMS 402 or may be provided in the storage battery 401. Alternatively, the monitoring device 100 may be provided in the server 601 on the Internet 600.

  When the battery group 10 is a secondary battery provided in the electric vehicle 408, the voltage detection unit 20 can also be provided in the electric vehicle 408. In this case, the function of the monitoring device 100 may be provided in the electric vehicle 408 or may be provided in the HEMS 402. For example, the function of the notification unit 103 of the monitoring device 100 may be realized by a monitor provided in the electric vehicle 408, for example.

  Furthermore, the monitoring device 100 is not necessarily realized by one device, and the monitoring device 100 may be realized by a plurality of devices that differ for each function. For example, a part of the function of the monitoring device 100 may be provided in the HEMS 402, and the other part of the function of the monitoring device 100 may be provided in the server 601. In the above description, the correspondence relationship between the monitoring device 100 and the hardware configuration in FIG. 12 is shown, but the same applies to the monitoring device 200, and the monitoring device 100 can be read as the monitoring device 200.

  While the present invention has been described with reference to the embodiments, the present invention is not limited to the above embodiments. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the technical idea of the present invention.

  For example, in the above embodiment, the occurrence of liquid leakage is detected using the first condition and the second condition, but the present invention is not limited to such an example. For example, the occurrence of liquid leakage can be detected using conditions other than the second condition together with the first condition. Alternatively, it may be determined that leakage has occurred when the first condition is satisfied, but the determination accuracy is improved by using other conditions such as the second condition together.

  The order in which the steps of the flowcharts shown in the above embodiments are executed does not necessarily have to be described. Unless otherwise specified, various modifications that can be conceived by those skilled in the art can be made. For example, in the above-described embodiment, the second condition is determined after the first condition is determined, but the present invention is not limited to such an example. For example, the determination of the second condition can be executed before the determination of the first condition.

Furthermore, in addition to the steps of the flowchart shown in the above embodiment, other conditions may be added for determining leakage. For example, although the first condition and the second condition are determined for all the battery cells 11 in the above embodiment, the present invention is not limited to such an example.
For example, the battery cells 11 that perform liquid leakage determination can be narrowed down using other conditions such as the SOH value. The determination of the first condition and the second condition may be performed only for the battery cell 11 whose SOH value is equal to or less than a predetermined threshold value.

  As an example of a power storage system to which the monitoring system of the above embodiment can be applied, a home power storage system has been described as an example, but the present invention is not limited to such an example. The monitoring system of the above embodiment can be applied to various power storage systems that use the battery cells 11. At this time, the functions of the monitoring devices 100 and 200 may be realized by one device or a plurality of devices. Monitoring devices 100 and 200, voltage detection unit 20, and battery group 10 may be provided in the same housing, or may be provided in separate housings. Various changes can be made to the hardware configuration.

A part or all of the above embodiment can be described as in the following supplementary notes, but is not limited thereto.
(Appendix 1) A monitoring device for monitoring the state of a plurality of battery cells,
A monitoring device comprising a liquid leakage detection unit that detects the occurrence of liquid leakage from the voltage of each battery cell using a first condition based on a voltage difference between battery cells after completion of discharge.
(Supplementary note 2) The monitoring device according to supplementary note 1, wherein the liquid leakage detection unit detects the occurrence of liquid leakage by further using a second condition based on a time-dependent decrease in cell voltage after completion of charging. .
(Additional remark 3) The said leak detection part has the voltage difference between the battery cells after completion of discharge larger than a 1st condition threshold value, and the time-dependent fall amount of the cell voltage after charge completion is more than a 2nd condition threshold value. If it is larger, the monitoring device according to appendix 2, wherein it is determined that liquid leakage has occurred.
(Appendix 4) The second condition is that the amount of time-dependent decrease in the cell voltage after completion of charging is greater than a second condition threshold,
The monitoring device according to appendix 2 or 3, wherein the leak detection unit uses a value corresponding to a degree of deterioration of each battery cell as the second condition threshold.
(Supplementary note 5) The monitoring apparatus according to any one of supplementary notes 1 to 4, further comprising a leakage level determination unit that determines a level of the leakage when the leakage detection unit detects the occurrence of leakage. .
(Additional remark 6) The said liquid leakage level determination part determines the level of the said liquid leakage based on the ratio from which the voltage value of a specific battery cell becomes the minimum among these battery cells in a predetermined period. 5. The monitoring device according to 5.
(Additional remark 7) The said liquid leakage level determination part determines the level of the said liquid leakage based on the execution frequency of the cell balance operation | movement which makes the voltage difference between battery cells small. Monitoring device.
(Additional remark 8) The said leak detection part determines whether the said 1st condition is satisfy | filled based on the execution frequency of the cell balance operation | movement which makes the voltage difference between cells small, and detects generation | occurrence | production of a leak. The monitoring device according to any one of appendices 1 to 7.
(Supplementary note 9) After the discharge is completed, when the voltage difference between the highest voltage value and the lowest voltage value among the voltages of the plurality of battery cells is equal to or greater than a predetermined first condition threshold, The monitoring apparatus according to any one of appendices 1 to 8, which determines that the first condition is satisfied.
(Additional remark 10) The said leakage detection part is a case where the amount of reduction | decrease of the voltage value of the high voltage cell with the highest voltage among these battery cells is more than a said 2nd condition threshold value after completion of charging, or these several The monitoring apparatus according to claim 3, wherein when the amount of decrease in the voltage value of the low-voltage cell having the lowest voltage among the battery cells is equal to or greater than the second condition threshold value, it is determined that the second condition is satisfied.
(Supplementary Note 11) When the difference between the actual value of the deterioration level and the estimated value for each battery cell is equal to or greater than the deterioration level threshold value, the leakage detection unit generates liquid leakage using the first condition. The monitoring device according to attachment 1, wherein the monitoring device is detected.
(Supplementary note 12) a plurality of battery cells;
A voltage detector for detecting a voltage value of each of the plurality of battery cells;
A monitoring device that monitors the state of the plurality of battery cells based on the voltage value;
The said monitoring apparatus is a monitoring system provided with the leak detection part which detects generation | occurrence | production of a leak using the 1st conditions based on the voltage difference between the battery cells after completion of discharge.
(Supplementary note 13) A monitoring method for monitoring the state of a plurality of battery cells,
Obtaining a voltage difference between the battery cells of the plurality of battery cells after completion of discharge;
Detecting the occurrence of liquid leakage using the first condition based on the voltage difference.

  This application claims the priority on the basis of Japanese application Japanese Patent Application No. 2016-56874 for which it applied on March 22, 2016, and takes in those the indications of all here.

DESCRIPTION OF SYMBOLS 11 Battery cell 20 Voltage detection part 100 Monitoring apparatus 101 Battery state acquisition part 102 Liquid leakage detection part 103 Notification part 200 Monitoring apparatus 203 Notification part 204 Liquid leakage level determination part 300 Monitoring apparatus

Claims (13)

A monitoring device for monitoring the state of a plurality of battery cells,
A monitoring device comprising a leakage detection means for detecting the occurrence of leakage from the voltage of each battery cell using a first condition based on a voltage difference between the battery cells after completion of discharge.   The monitoring device according to claim 1, wherein the leakage detection unit detects the occurrence of leakage by further using a second condition based on a time-dependent decrease in cell voltage after completion of charging.   The liquid leakage detection means, when the voltage difference between the battery cells after the completion of discharge is larger than the first condition threshold, and the amount of decrease in the cell voltage over time after the completion of charging is greater than the second condition threshold, The monitoring device according to claim 2, wherein the monitoring device determines that leakage has occurred. The second condition is that the amount of decrease in cell voltage over time after completion of charging is greater than a second condition threshold value,
The monitoring device according to claim 2 or 3, wherein the leak detection unit uses a value corresponding to a degree of deterioration of each battery cell as the second condition threshold.   The monitoring apparatus according to any one of claims 1 to 4, further comprising a leakage level determination unit that determines a level of the leakage when the leakage detection unit detects the occurrence of leakage.   The said leak level determination means determines the level of the said leak based on the ratio from which the voltage value of a specific battery cell becomes the minimum among these battery cells in a predetermined period. Monitoring device.   The monitoring device according to claim 5, wherein the leakage level determination unit determines the leakage level based on a frequency of execution of a cell balance operation that reduces a voltage difference between battery cells.   The liquid leakage detection means determines whether or not the first condition is satisfied based on a frequency of execution of a cell balance operation for reducing a voltage difference between cells, and detects the occurrence of liquid leakage. 8. The monitoring device according to any one of 1 to 7.   When the voltage difference between the highest voltage value and the lowest voltage value among the voltages of the plurality of battery cells is equal to or greater than a predetermined first condition threshold value after the discharge is completed, The monitoring apparatus according to claim 1, wherein the monitoring apparatus determines that the condition is satisfied.   The liquid leakage detection means, after completion of charging, when the amount of decrease in the voltage value of the high voltage cell having the highest voltage among the plurality of battery cells is equal to or greater than the second condition threshold, or among the plurality of battery cells The monitoring apparatus according to claim 3, wherein when the amount of decrease in the voltage value of the lowest voltage cell having the lowest voltage is equal to or greater than the second condition threshold, it is determined that the second condition is satisfied.   The liquid leakage detection means detects the occurrence of liquid leakage using the first condition when the difference between the actual value of the deterioration level and the estimated value for each battery cell is equal to or greater than the deterioration level threshold. The monitoring apparatus according to claim 1. A plurality of battery cells;
Voltage detecting means for detecting the voltage value of each of the plurality of battery cells;
A monitoring device that monitors the state of the plurality of battery cells based on the voltage value;
The monitoring system includes a liquid leakage detection unit that detects occurrence of liquid leakage using a first condition based on a voltage difference between battery cells after completion of discharge. A monitoring method for monitoring a state of a plurality of battery cells,
Obtaining a voltage difference between the battery cells of the plurality of battery cells after completion of discharge;
Detecting the occurrence of liquid leakage using the first condition based on the voltage difference.

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