Degradation diagnosis device, degradation diagnosis system, and degradation diagnosis method

Abstract

The deterioration diagnosis device includes a resistance calculation unit that calculates the resistance of a storage battery of the storage battery system; a capacity calculation unit that calculates the capacity of the storage battery when the storage battery system is in use; a correlation determination unit that determines a correlation between the resistance and capacity of the storage battery based on the calculated resistance and capacity; and a capacity estimation unit that estimates the capacity of the storage battery in a capacity estimation interval between the x-1th use and the xth use of the storage battery system based on the correlation, wherein the resistance calculation unit calculates the resistance multiple times in a pre-estimation interval up to the x-1th use of the storage battery system and calculates the resistance in the capacity estimation interval, the correlation determination unit determines the correlation based on the resistance calculated in the pre-estimation interval and the capacity calculated during at least two uses among the 1st to the x-1th uses of the storage battery system, and the capacity estimation unit estimates the capacity of the storage battery based on the correlation and the resistance calculated in the capacity estimation interval.

Description

[Technical field]

[0001] The present disclosure relates to a degradation diagnosis device, a degradation diagnosis system, and a degradation diagnosis method. [Background technology]

[0002] In data centers and the like, storage battery systems are provided as emergency power sources to supply power to various devices in the event of an emergency in which power supply from the power grid is cut off. For example, an uninterruptible power supply (UPS) is used as the storage battery system.

[0003] In order to reliably supply power from the battery system to each device in a data center in an emergency, it is necessary to diagnose the deterioration of the battery system and know when to replace the battery system. Patent Document 1 discloses a capacity estimation method and a deterioration diagnosis device for a battery pack used as an emergency power source. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2003-22844 Summary of the Invention [Problem to be solved by the invention]

[0005] In order to diagnose the deterioration of the battery storage system, it is possible to stop the data center, forcibly discharge the battery storage system, and check the capacity of the battery storage system. In this case, the data center needs to be stopped for a long time, which may cause a disruption to the operation of the data center. In addition, the timing for performing the deterioration diagnosis of the battery storage system is limited.

[0006] In Patent Document 1, the internal resistance and capacity of at least two of the multiple cells that make up the battery pack are measured, and a linear equation that expresses the correlation between the internal resistance and capacity is determined based on the measurement results. The capacity of the battery pack is estimated by introducing the internal resistance of the other cells into this linear equation. In the structure of Patent Document 1, data for deterioration diagnosis, such as the correlation between the internal resistance and capacity of the storage battery, must be obtained in advance.

[0007] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a degradation diagnosis device, a degradation diagnosis system, and a degradation diagnosis method that are capable of performing degradation diagnosis of a storage battery system at any time without obtaining data for degradation diagnosis in advance. [Means for solving the problem]

[0008] A degradation diagnosis device according to the present disclosure is a degradation diagnosis device that diagnoses degradation of a storage battery system, and includes a resistance calculation unit that calculates a resistance of a storage battery of the storage battery system, a capacity calculation unit that calculates a capacity of the storage battery when the storage battery system is in use, a correlation determination unit that determines a correlation between the resistance and capacity of the storage battery based on the resistance calculated by the resistance calculation unit and the capacity calculated by the capacity calculation unit, and a capacity estimation unit that estimates a capacity of the storage battery in a capacity estimation interval between an x-1th use and an xth use of the storage battery system based on the correlation, where x is an integer equal to or greater than 3. the resistance calculation unit calculates the resistance a plurality of times in a pre-estimation interval up to an x-1th use of the storage battery system, and calculates the resistance in the capacity estimation interval, the correlation determination unit determines the correlation based on the resistance calculated by the resistance calculation unit in the pre-estimation interval and the capacity calculated by the capacity calculation unit during at least two uses among a 1st to an x-1th use of the storage battery system, and the capacity estimation unit estimates the capacity of the storage battery based on the correlation and the resistance calculated by the resistance calculation unit in the capacity estimation interval.

[0009] A deterioration diagnosis system according to the present disclosure includes the deterioration diagnosis device and the storage battery system, and the storage battery system has a storage battery and a storage battery control unit that controls the storage battery.

[0010] A degradation diagnosis method according to the present disclosure is a degradation diagnosis method for diagnosing degradation of a storage battery system, the degradation diagnosis method including: a resistance calculation step for calculating a resistance of a storage battery of the storage battery system; a capacity calculation step for calculating a capacity of the storage battery when the storage battery system is in use; a correlation determination step for determining a correlation between the resistance and capacity of the storage battery based on the resistance calculated in the resistance calculation step and the capacity calculated in the capacity calculation step; and a capacity estimation step for estimating a capacity of the storage battery in a capacity estimation interval between an x-1th use and an xth use of the storage battery system based on the correlation, where x is an integer equal to or greater than 3. and a step of calculating the resistance in the resistance calculation step, the resistance is calculated a plurality of times in a pre-estimation interval up to the x-1th use of the storage battery system, and the resistance is calculated in the capacity estimation interval. In the correlation determination step, the correlation is determined based on the resistance calculated in the resistance calculation step in the pre-estimation interval and the capacity calculated in the capacity calculation step during at least two uses among a 1st to an x-1th use of the storage battery system. In the capacity estimation step, the capacity of the storage battery is estimated based on the correlation and the resistance calculated in the resistance calculation step in the capacity estimation interval. Effect of the Invention

[0011] According to the present disclosure, it is possible to provide a degradation diagnosis device, a degradation diagnosis system, and a degradation diagnosis method that can perform degradation diagnosis of a storage battery system at any timing without obtaining data for degradation diagnosis in advance. [Brief description of the drawings]

[0012] [Figure 1A] FIG. 2 is a diagram illustrating an overall configuration of a data center according to a first embodiment during normal operation. [Figure 1B] FIG. 2 is a diagram illustrating an overall configuration of a data center according to a first embodiment in an emergency. [Diagram 2] 2 is a block diagram of a UPS, a calculation unit, and a display unit according to the first embodiment. [Diagram 3] 1 is a graph showing a change in the SOC of a storage battery according to a change in the usage state of a UPS. [Figure 4] 4 is a diagram for explaining calculation of the resistance and capacity of a storage battery and estimation of the capacity of the storage battery by a calculation unit according to the first embodiment. FIG. [Figure 5A] 1 is a graph showing an example of a voltage curve when a UPS is used from an upper limit voltage to a lower limit voltage. [Figure 5B] 1 is a graph showing an example of a current curve when a UPS is used from an upper limit voltage to a lower limit voltage. [Figure 5C] 1 is a graph showing an example of an SOC curve when a UPS is used from an upper limit voltage to a lower limit voltage. [Figure 6] 4 is a diagram for explaining estimation of the capacity of a storage battery by a calculation unit according to the first embodiment. FIG. [Figure 7] 4 is a flowchart showing an example of processing executed by the degradation diagnosis device according to the first embodiment. [Figure 8] 13 is a diagram for explaining estimation of the capacity of a storage battery by a calculation unit according to the second embodiment. FIG. [Figure 9] 13 is a diagram for explaining calculation of the resistance and capacity of a storage battery and estimation of the capacity of the storage battery by a calculation unit according to the third embodiment. FIG. [Figure 10A] 1 is a graph showing a normal distribution of resistance estimation errors. [Figure 10B] 1 is a graph showing a normal distribution of capacity estimation errors. [Figure 11] 13 is a diagram for explaining estimation of the capacity of a storage battery by a calculation unit according to the third embodiment. FIG. [Figure 12] FIG. 13 is a diagram for explaining estimation of the capacity of a storage battery by a calculation unit according to the fourth embodiment. [Figure 13] 1 is a graph showing changes in the capacity maintenance rate of a storage battery. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the scope of the present disclosure is not limited to the following embodiments, and may be modified as desired within the scope of the technical concept of the present disclosure.

[0014] Embodiment 1 First, there will be described a degradation diagnosis device, a degradation diagnosis system, and a degradation diagnosis method according to embodiment 1. The degradation diagnosis device according to the present embodiment is installed in a data center 1.

[0015] 1A and 1B are diagrams showing the overall configuration of a data center 1. As shown in FIG. 1A and FIG. 1B, the data center 1 is composed of a UPS (Uninterruptible Power Supply) 11, a server / storage 12, an AC / DC converter 13, a DC / DC converter 14, a pulse generating device 15, a calculation unit 16, a display unit 17, and the like. The data center 1 is connected to a power system 2. The UPS 11 is an example of a storage battery system. The pulse generating device 15, the calculation unit 16, and the display unit 17 constitute a degradation diagnosis device that diagnoses degradation of the UPS 11. The UPS 11, the pulse generating device 15, the calculation unit 16, and the display unit 17 constitute a degradation diagnosis system.

[0016] The server storage 12 is a device for storing data for a long period of time. The server storage 12 is used in devices such as computers and data communications. The server storage 12 is connected to the power system 2 via an AC / DC converter 13 and a DC / DC converter 14. The server storage 12 is connected to the UPS 11 via the DC / DC converter 14. In normal times, the server storage 12 is powered by the power system 2. At this time, the UPS 11 is not used and is in a standby state. In an emergency in which the power supply from the power system 2 to the server storage 12 is cut off, the server storage 12 is powered by the UPS 11. Hereinafter, the normal times will also be referred to as a time when the UPS 11 is not in use. The emergency times will also be referred to as a time when the UPS 11 is in use.

[0017] The UPS 11 includes a storage battery 21 and a BMU (Battery Management Unit) 22 (a storage battery control unit).

[0018] The storage battery 21 is a rechargeable secondary battery, and may be, for example, a lithium ion battery, a nickel metal hydride battery, or a lead storage battery. The BMU 22 controls charging and discharging of the storage battery 21. The BMU 22 has a protection function for preventing overcharging, overdischarging, overvoltage, overcurrent, temperature abnormality, and the like of the storage battery 21 based on the upper and lower limit voltages, maximum charge and discharge current, maximum cell temperature, and the like of the storage battery 21. The BMU 22 has a function for monitoring the state of the storage battery 21, such as voltage measurement, current measurement, power measurement, temperature measurement, full charge management, and remaining capacity management of the storage battery 21. The UPS 11 is provided with measurement sensors for measuring the voltage, current, and temperature of the storage battery 21. The measurement sensors include, for example, a voltage probe for measuring the voltage of the storage battery 21, a shunt resistor or Hall type current sensor for measuring the current of the storage battery 21, and a thermocouple for measuring the temperature of the storage battery 21.

[0019] The UPS 11 is connected to the power system 2. Normally (that is, when the UPS 11 is not in use), the UPS 11 is constantly charged by the power system 2.

[0020] 3 is a diagram showing a transition of the SOC (State Of Charge) of the storage battery 21 in response to a change in the usage state of the UPS 11. When the SOC is 0(%), it indicates that the storage battery 21 is in a completely discharged state, and when the SOC is 100(%), it indicates that the storage battery 21 is in a fully charged state.

[0021] As shown in FIG. 3, the SOC of the storage battery 21 is divided into an area A1 where the SOC remains at 100(%), an area A2 where the SOC decreases from 100(%) to X(%), and an area A3 where the SOC recovers from X(%) to 100(%).

[0022] Area A1 corresponds to a time when the UPS 11 is not in use. At this time, the storage battery 21 is not used to supply power to the server / storage 12, and is charged by the power system 2 to maintain a fully charged state. Area A2 corresponds to the time when the UPS 11 is in use. At this time, power supply from the power grid 2 to the server / storage 12 is cut off. The storage battery 21 is discharged to supply power to the server / storage 12, and the SOC of the storage battery 21 decreases. Area A3 corresponds to a time when the UPS 11 is not in use. In area A3, the power system 2 recovers, and the power supply to the server / storage 12 is switched from the UPS 11 to the power system 2. The storage battery 21 is charged by the power system 2 and returns to a fully charged state. Depending on the use of the UPS 11, the areas A1 to A3 are repeated.

[0023] In the data center 1, when the power system 2 is restored, the power supply to the server / storage 12 is switched from the UPS 11 to the power system 2, so in many cases the use of the UPS 11 ends without the storage battery 21 being completely discharged (i.e., the SOC does not drop to 0(%)). In FIG. 3, a case is shown in which the SOC of the storage battery 21 drops to X(%) in area A2, but the value of X differs depending on the time when the power supply from the power system 2 to the server / storage 12 is cut off. In the data center 1, the UPS 11 is used only in emergencies, so it is used infrequently and is often on standby in a fully charged state (i.e., in area A1).

[0024] The AC / DC converter 13 converts the AC power from the power system 2 into DC power. The DC / DC converter 14 converts the voltage of the power from the UPS 11 to a voltage suitable for the server / storage 12. The DC / DC converter 14 converts the voltage of the power from the power system 2 to a voltage suitable for the server / storage 12.

[0025] The pulse generator 15 is provided between the UPS 11 and the DC / DC converter 14. The pulse generator 15 switches on and off the discharge from the storage battery 21 of the UPS 11 to the server storage 12 by switching on and off the conduction of current between the UPS 11 and the DC / DC converter 14. The pulse generator 15 has a switch 25 and a pulse generating unit 26.

[0026] The pulse generating section 26 generates a pulse signal for switching the switch 25 between the on state and the off state.

[0027] The switch 25 is switched between an on state and an off state by a pulse signal from the pulse generating unit 26, thereby switching on and off the conduction of current between the UPS 11 and the DC / DC converter 14.

[0028] When the switch 25 is in the on state, power is discharged from the UPS 11 to the server / storage 12. In normal operation shown in Fig. 1A, when the switch 25 is in the on state, power is supplied to the server / storage 12 from both the power system 2 and the UPS 11. In emergency operation shown in Fig. 1B, the switch 25 is always in the on state, and power is supplied to the server / storage 12 from the UPS 11. When the switch 25 is in the OFF state, the current is cut off between the UPS 11 and the DC / DC converter 14 , and no power is discharged from the UPS 11 to the server / storage 12 .

[0029] The pulse generating device 15 may be configured, for example, with a resistor and a switch, as long as it is capable of switching on and off the discharge from the UPS 11 to the server / storage 12. In this case, the resistor may be, for example, a variable resistor, and the discharge from the UPS 11 to the server / storage 12 may be switched on and off by switching the resistance value in a pulse-like manner.

[0030] The calculation unit 16 estimates the capacity of the storage battery 21 in a capacity estimation section P1 between the x-1th use and the xth use of the UPS 11, and calculates a capacity maintenance rate of the storage battery 21 based on the estimated capacity of the storage battery 21. Here, x is an integer equal to or greater than 3. The capacity estimation section P1 corresponds to a time when the UPS 11 is not in use. In the following description, the section from the initial state to the x-1th use of the UPS 11 is referred to as a pre-estimation section P2. The pre-estimation section P2 includes the x-1th use of the UPS 11.

[0031] Fig. 2 is a block diagram of the UPS 11, the calculation unit 16, and the display unit 17. As shown in Fig. 2, the calculation unit 16 has an acquisition unit 31, a resistance calculation unit 32, a capacity calculation unit 33, a storage unit 34, a deterioration amount estimation unit 35, and a control unit 36.

[0032] The control unit 36 ​​controls the acquisition unit 31, the resistance calculation unit 32, the capacity calculation unit 33, and the deterioration amount estimation unit 35 by executing a program using a CPU (Central Processing Unit) or the like. The control unit 36 ​​also controls the pulse generation device 15. For example, the control unit 36 ​​gives an instruction to the pulse generation device 15 to generate a pulse signal for discharging the storage battery 21. Note that the control unit that controls the pulse generation device 15 may be provided separately from the control unit 36.

[0033] The acquisition unit 31 acquires, from the UPS 11, parameters of the storage battery 21 used for estimating the capacity of the storage battery 21. The parameters of the storage battery 21 include, for example, a current, a voltage, and a temperature of the storage battery 21. The acquisition unit 31 acquires the parameters of the storage battery 21 from the BMU 22. Note that the acquisition unit 31 may acquire the parameters of the storage battery 21 from a measurement sensor provided in the UPS 11, without going through the BMU 22.

[0034] The resistance calculation unit 32 calculates the resistance of the storage battery 21 based on the parameters of the storage battery 21 acquired by the acquisition unit 31. Specifically, the resistance calculation unit 32 calculates the resistance of the storage battery 21 based on the current and voltage responses of the storage battery 21 when the storage battery 21 is discharged. The discharge time of the storage battery 21 for calculating the resistance of the storage battery 21 is, for example, about 1 to 10 seconds. The calculated resistance is stored in the storage unit 34.

[0035] The resistance R of the storage battery 21 is calculated from the following formula (1) according to Ohm's law. In the following formula (1), I is the current of the storage battery 21 when the storage battery 21 is discharged, and V is the voltage of the storage battery 21 when the storage battery 21 is discharged. OCV is the open circuit voltage of the storage battery 21. The open circuit voltage of the storage battery 21 is the voltage when the storage battery 21 is left stationary in an unloaded state and there is no longer any voltage fluctuation.

[0036]

number

[0037] The resistance of the storage battery 21 varies depending on the temperature of the storage battery 21. Therefore, it is preferable that the temperature of the storage battery 21 is constant when the resistance of the storage battery 21 is calculated. When the temperature of the storage battery 21 varies, the resistance calculation unit 32 may correct the resistance of the storage battery 21 based on the temperature change of the storage battery 21. For example, a reference temperature may be determined in advance, and the resistance calculation unit 32 may correct the resistance of the storage battery 21 based on the difference between the temperature of the storage battery 21 and the reference temperature.

[0038] In Fig. 4, the resistance calculated by the resistance calculation unit 32 is indicated by a triangle. As shown in Fig. 4, the resistance calculation unit 32 calculates the resistance of the storage battery 21 multiple times in the pre-estimation interval P2. In addition, the resistance calculation unit 32 calculates the resistance of the storage battery 21 in the capacity estimation interval P1.

[0039] The pre-estimation section P2 includes an area A2 corresponding to when the UPS 11 is in use, and areas A1 and A3 corresponding to when the UPS 11 is not in use. The resistance calculation unit 32 calculates the resistance of the storage battery 21 in the areas A2 and A1 of the pre-estimation section P2. In the area A2 of the pre-estimation section P2, the resistance calculation unit 32 calculates the resistance of the storage battery 21 based on the current and voltage response of the storage battery 21 when power is supplied from the UPS 11 to the server storage 12. In the area A1 of the pre-estimation section P2, the resistance calculation unit 32 calculates the resistance of the storage battery 21 based on the current and voltage response of the storage battery 21 when the storage battery 21 is discharged by the pulse generating device 15 for a predetermined discharge time. In the area A2, the resistance of the storage battery 21 does not need to be calculated.

[0040] The capacity calculation unit 33 calculates the capacity of the storage battery 21 when the UPS 11 is in use, based on the parameters of the storage battery 21 acquired by the acquisition unit 31. The calculated capacity is stored in the storage unit . 4, the capacities calculated by the capacity calculation unit 33 are indicated by black circles. As shown in FIG 4, the capacity calculation unit 33 calculates the capacity of the storage battery 21 every time the UPS 11 is used.

[0041] Figure 5A shows the UPS 11 at an upper limit voltage V U to lower limit voltage V LFIG. 5A is a graph showing a voltage curve when the storage battery 21 is used until the battery 21 is fully discharged. FIG. 5B is a graph showing a current curve in the above case. FIG. 5C is a graph showing an SOC curve in the above case. In FIGS. 5A to 5C, time t1 is the time when the use of the UPS 11 starts (i.e., the time when the operation switches from normal to emergency), time t2 is the time when the current value changes from I1 to I2 due to a change in the usage status of the server / storage 12, which is the load, and time t3 is the time when the use of the UPS 11 ends (i.e., the time when the operation switches from emergency to normal). As shown in FIGS. 5A to 5C, the voltage, current, and SOC of the storage battery 21 are interrelated.

[0042] The capacity of the storage battery 21 can be calculated by integrating the current of the storage battery 21. For example, when the SOC of the storage battery 21 changes from 100(%) to 0(%) due to use of the UPS 11, the capacity Q of the storage battery 21 is calculated as in the following formula (2). Specifically, the capacity Q of the storage battery 21 is obtained by integrating the current I when the SOC changes from 100(%) to 0(%). The unit of the capacity Q of the storage battery 21 is Ah or Wh.

[0043]

number

[0044] Here, since the UPS 11 is used temporarily when the power system 2 is interrupted, it is rarely used from a fully charged state to a completely discharged state at a constant current or voltage. When the UPS 11 is used, if the UPS 11 is not used until it is fully discharged and the SOC changes from a(%) to b(%), the capacity Q of the storage battery 21 is calculated as in the following formula (3). Specifically, the current I of partial discharge when the SOC changes from a(%) to b(%) is integrated. The integrated result is multiplied by 100 / (ab) to obtain the capacity Q.

[0045]

number

[0046] The capacity of the storage battery 21 varies depending on the temperature of the storage battery 21. Therefore, it is preferable that the temperature of the storage battery 21 is constant when calculating the capacity of the storage battery 21. When the temperature of the storage battery 21 varies, the capacity calculation unit 33 may correct the capacity of the storage battery 21 based on the temperature change of the storage battery 21. For example, a reference temperature may be determined in advance, and the capacity calculation unit 33 may correct the capacity of the storage battery 21 based on the difference between the temperature of the storage battery 21 and the reference temperature.

[0047] The resistance calculated by the resistance calculation unit 32 and the capacitance calculated by the capacitance calculation unit 33 are stored as past data in the storage unit 34. The storage unit 34 is realized by a non-volatile or volatile semiconductor memory such as a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable Read Only Memory), or an EEPROM (Electrically Erasable and Programmable ROM).

[0048] The deterioration amount estimation unit 35 estimates the deterioration amount of the storage battery 21 based on the resistance of the storage battery 21 calculated by the resistance calculation unit 32 and the capacity of the storage battery 21 calculated by the capacity calculation unit 33. The deterioration amount estimation unit 35 has a correlation determination unit 41, a capacity estimation unit 42, and a capacity maintenance rate calculation unit 43.

[0049] The correlation determination unit 41 determines the correlation between the resistance and capacity of the storage battery 21 based on the resistance of the storage battery 21 calculated by the resistance calculation unit 32 and the capacity of the storage battery 21 calculated by the capacity calculation unit 33 .

[0050] FIG. 6 is a diagram for explaining the estimation of the capacity of the storage battery 21 by the calculation unit 16. In FIG. 6, the vertical axis indicates the capacity of the storage battery 21, and the horizontal axis indicates the resistance of the storage battery 21. Q1, Q2, . . . Qx-1 indicate the capacity of the storage battery 21 calculated by the capacity calculation unit 33 when the UPS 11 is used for the first, second, and x-1 times, respectively. R1, R2, . . . Rx-1 indicate the resistance of the storage battery 21 calculated by the capacity calculation unit 33 when the UPS 11 is used for the first, second, and x-1 times, respectively. In addition, when the calculation of the resistance of the storage battery 21 is not performed in the area A2, the resistances R1, R2, . . . Rx-1 of the storage battery 21 may be calculated based on the resistance of the storage battery 21 calculated by the resistance calculation unit 32 in the area A1. As shown in FIG. 6, the resistance of the storage battery 21 and the capacity of the storage battery 21 have a correlation. That is, when the UPS 11 deteriorates with use and the capacity of the storage battery 21 decreases, the resistance of the storage battery 21 increases.

[0051] The correlation determination unit 41 determines the correlation between the resistance and capacity of the storage battery 21 by obtaining an approximation curve Le that represents the correlation between the resistance and capacity of the storage battery 21. For example, in the example of Fig. 6, the approximation curve Le is expressed as a linear function by the following formula (4). Note that the approximation curve Le is not limited to a linear function as long as it is a function that can represent the correlation between the resistance and capacity of the storage battery 21.

[0052]

number

[0053] The correlation determination unit 41 determines the coefficient A and the constant B in the formula (4) based on the resistances R1, R2, . . . Rx-1 of the storage battery 21 calculated by the resistance calculation unit 32 and the capacities Q1, Q2, . . . Qx-1 of the storage battery 21 calculated by the capacity calculation unit 33. In this case, the correlation determination unit 41 can determine the correlation between the resistance and the capacity of the storage battery 21 by using at least two capacities of the capacities Q1, Q2, . . . Qx-1 of the storage battery 21 calculated by the capacity calculation unit 33. In order to improve accuracy, it is preferable to determine the correlation between the resistance and the capacity of the storage battery 21 by using three or more capacities of the capacities Q1, Q2, . . . Qx-1 of the storage battery 21 calculated by the capacity calculation unit 33.

[0054] The capacity estimation unit 42 estimates the capacity of the storage battery 21 in the capacity estimation interval P1 based on the correlation determined by the correlation determination unit 41 and the resistance of the storage battery 21 calculated in the capacity estimation interval P1 by the resistance calculation unit 32. Specifically, the capacity estimation unit 42 estimates the capacity Qe of the storage battery 21 in the capacity estimation interval P1 by introducing the resistance Re of the storage battery 21 calculated in the capacity estimation interval P1 by the resistance calculation unit 32 into the above formula (4).

[0055] The capacity maintenance rate calculation unit 43 calculates the capacity maintenance rate of the storage battery 21 based on the capacity Q of the storage battery 21. When the capacity maintenance rate of the storage battery 21 in the initial state until the UPS 11 is used for the first time is set to 100(%) (i.e., when the deterioration amount of the storage battery 21 is set to 0(%)), the capacity maintenance rate M(%) is expressed by the following formula (5). It should be noted that Q0 is the capacity of the storage battery 21 in the initial state. The capacity Q0 of the storage battery 21 can be estimated based on the resistances R1, R2, . . . Rx-1 of the storage battery 21 calculated by the resistance calculation unit 32 and the capacities Q1, Q2, . . . Qx-1 of the storage battery 21 calculated by the capacity calculation unit 33.

[0056]

number

[0057] When the capacity maintenance rate calculated by the capacity maintenance rate calculation unit 43 is equal to or lower than the threshold value, it is determined that the life of the UPS 11 has arrived. The threshold value may be, for example, 80(%) or 60(%). The deterioration amount estimation unit 35 may calculate the life of the UPS 11 or the replacement time of the UPS 11 based on the capacity maintenance rate calculated by the capacity maintenance rate calculation unit 43.

[0058] The display unit 17 is a display device such as a display. The display unit 17 displays parameters of the storage battery 21, the capacity of the storage battery 21, and the capacity maintenance rate of the storage battery 21. When the deterioration amount estimation unit 35 calculates the life or replacement time of the UPS 11, the display unit 17 may display the life or replacement time of the UPS 11.

[0059] FIG. 7 is a flowchart showing an example of the process flow of a degradation diagnosis method for the UPS 11.

[0060] First, it is determined whether the UPS 11 is in use (step S101).

[0061] If the UPS 11 is being used (step S101: YES), the UPS 101 discharges power to the server / storage 12, which is a load (step S102). The acquisition unit 31 acquires parameters of the storage battery 21 when the UPS 11 is in use (step S103). The resistance calculation unit 32 calculates the resistance of the storage battery 21 based on the parameters of the storage battery 21 acquired in step S103 (step S104). Step S104 corresponds to a resistance calculation step. The calculated resistance of the storage battery 21 is stored in the storage unit . The capacity calculation unit 33 calculates the capacity of the storage battery 21 based on the parameters of the storage battery 21 acquired in step S103 (step S105). Step S105 corresponds to a capacity calculation step. The calculated capacity of the storage battery 21 is stored in the storage unit . The process then proceeds to step S110.

[0062] If the UPS 11 is not in use (step S101: NO), the control unit 36 ​​causes the pulse generating unit 26 of the pulse generating device 15 to generate a pulse signal and causes the storage battery 21 to discharge for the discharge time (step S106). The acquiring unit 31 acquires the parameters of the storage battery 21 when the storage battery 21 is discharged by the pulse generating device 15 (step S107). The resistance calculation unit 32 calculates the resistance of the storage battery 21 based on the parameters of the storage battery 21 acquired in step S107 (step S108). Step S108 corresponds to a resistance calculation step. The deterioration amount estimation unit 35 determines a correlation between the resistance and capacity of the storage battery 21 based on the resistance of the storage battery 21 calculated in step S104 and the capacity of the storage battery 21 calculated in step S105, and estimates the capacity of the storage battery 21 based on the determined correlation and the resistance of the storage battery 21 calculated in step S108 (step S109). Step S109 corresponds to a correlation determination step and a capacity estimation step. The process then proceeds to step S110.

[0063] Thereafter, the control unit 36 ​​determines whether or not to end the deterioration diagnosis of the UPS 11 (step S110). If step S110 is YES, the process ends. If step S110 is NO, the process returns to step S101. For example, if it is preferable to continue estimating the capacity of the storage battery 21, step S110 is determined as NO. If the state of the storage battery 21 can be sufficiently grasped, step S110 is determined as YES, and the process ends.

[0064] As described above, the degradation diagnosis device according to the present embodiment includes a resistance calculation unit 32 that calculates the resistance of the storage battery 21 of the UPS 11, a capacity calculation unit 33 that calculates the capacity of the storage battery 21 when the UPS 11 is in use, a correlation determination unit 41 that determines a correlation between the resistance and capacity of the storage battery 21 based on the resistance calculated by the resistance calculation unit 32 and the capacity calculated by the capacity calculation unit 33, and a capacity estimation unit 42 that estimates the capacity of the storage battery 21 in a capacity estimation section P1 between the x-1th use and the xth use of the UPS 11 based on the correlation, where x is an integer of 3 or more. The resistance calculation unit 32 calculates the resistance multiple times in a pre-estimation section P2 up to the x-1th use of the UPS 11, and calculates the resistance in the capacity estimation section P1. The correlation determination unit 41 determines the correlation based on the resistance calculated by the resistance calculation unit 32 in the pre-estimation section P2 and the capacity calculated by the capacity calculation unit 33 at least two times among the first use to the x-1th use of the UPS 11. The capacity estimation unit 42 estimates the capacity of the storage battery 21 based on the correlation and the resistance calculated by the resistance calculation unit 32 in the capacity estimation section P1. Moreover, a degradation diagnosis system according to the present disclosure includes the above-described degradation diagnosis device and a UPS 11. The UPS 11 includes a storage battery 21 and a BMU 22 that controls the storage battery 21.

[0065] The degradation diagnosis method according to the present embodiment includes a resistance calculation step of calculating the resistance of the storage battery 21 of the UPS 11, a capacity calculation step of calculating the capacity of the storage battery 21 when the UPS 11 is in use, a correlation determination step of determining a correlation between the resistance and capacity of the storage battery 21 based on the resistance calculated in the resistance calculation step and the capacity calculated in the capacity calculation step, and a capacity estimation step of estimating the capacity of the storage battery 21 in a capacity estimation section P1 between the x-1th use and the xth use of the UPS 11 based on the correlation, where x is an integer of 3 or more. In the resistance calculation step, the resistance is calculated multiple times in a pre-estimation section P2 up to the x-1th use of the UPS 11, and the resistance is calculated in the capacity estimation section P1. In the correlation determination step, the correlation is determined based on the resistance calculated in the resistance calculation step in the pre-estimation section P2 and the capacity calculated in the capacity calculation step during at least two uses among the first use to the x-1th use of the UPS 11. In the capacity estimation step, the capacity of the storage battery 21 is estimated based on the correlation and the resistance calculated in the resistance calculation step in the capacity estimation section P1.

[0066] The capacity of the storage battery 21 in a capacity estimation section P1 between the x-1th use and the xth use of the UPS 11 can be estimated by calculating the resistance of the storage battery 21 in the capacity estimation section P1. Therefore, the deterioration diagnosis of the UPS 11 can be performed at any timing without stopping the data center 1. In addition, the correlation between the resistance and the capacity of the storage battery 21 can be determined based on the resistance calculated in the pre-estimation section P2 and the capacity calculated at least two uses among the nth to x-1th uses of the UPS 11. Therefore, the deterioration diagnosis of the UPS 11 can be performed without acquiring data for the deterioration diagnosis in advance. Therefore, the maintainability and versatility can be improved.

[0067] The degradation diagnosis device further includes a pulse generator 15 having a pulse generator 26 that generates a pulse signal, and a switch 25 that is switched between an on state and an off state by the pulse signal, and discharging the storage battery 21 by switching the switch 25. A resistance calculator 32 calculates the resistance of the storage battery 21 based on the measurement results of the current and voltage of the storage battery 21 when the storage battery 21 is discharged by the pulse generator 15 in the capacity estimation section P1. This allows the pulse generator 15 to easily perform degradation diagnosis of the UPS 11 at any timing.

[0068] In addition, the degradation diagnosis device further includes a capacity maintenance rate calculation unit 43 that calculates a capacity maintenance rate based on the capacity of the storage battery 21 estimated by the capacity estimation unit 42. This makes it possible to easily grasp the degradation state of the UPS 11.

[0069] The degradation diagnostic device further includes a display unit 17 on which the result of estimation of the capacity of the storage battery 21 by the capacity estimation unit 42 is displayed. This allows the degradation diagnosis result of the UPS 11 to be easily understood.

[0070] Embodiment 2 Next, a description will be given of a degradation diagnosis device, a degradation diagnosis system, and a degradation diagnosis method according to embodiment 2. The degradation diagnosis device according to this embodiment has a basic configuration similar to that of embodiment 1, so the description will focus on the differences.

[0071] The capacity of the storage battery 21 decreases significantly in the early stages as the UPS 11 is used. In this embodiment, the correlation determination unit 41 determines the correlation by excluding the resistance and capacity at the early stages from the resistance calculated by the resistance calculation unit 32 and the capacity calculated by the capacity calculation unit 33. In the example of Fig. 8, the correlation determination unit 41 determines the correlation (i.e., the approximation curve Le) by excluding the resistance R1 and capacity Q1 of the storage battery 21 during the first use of the UPS 11 and the resistance R2 and capacity Q2 of the storage battery 21 during the second use of the UPS 11.

[0072] As described above, in this embodiment, the correlation determination unit 41 determines the correlation based on the resistance calculated by the resistance calculation unit 32 in the pre-estimation section P2 and the capacity calculated by the capacity calculation unit 33 during at least two uses among the nth to x-1th uses of the UPS 11, where n is an integer equal to or greater than 2 and x is an integer equal to or greater than 4. This improves the accuracy of diagnosis of the UPS 11. It is more preferable that n is 3 or more and x is 5 or more.

[0073] Embodiment 3 Next, a description will be given of a degradation diagnosis device, a degradation diagnosis system, and a degradation diagnosis method according to embodiment 3. The degradation diagnosis device according to this embodiment has a basic configuration similar to that of embodiment 1, so the description will focus on the differences.

[0074] In this embodiment, the correlation determination unit 41 determines the correlation by excluding resistances and capacities with large errors from among the resistances calculated by the resistance calculation unit 32 and the capacities calculated by the capacity calculation unit 33. Specifically, as shown in FIG. 9, the correlation determination unit 41 determines a resistance estimation curve Lr indicating a change in the resistance of the storage battery 21 over time based on the resistances calculated by the resistance calculation unit 32. The correlation determination unit 41 determines a capacity estimation curve Lc indicating a change in the resistance of the storage battery 21 over time based on the capacity calculated by the capacity calculation unit 33. The correlation determination unit 41 determines the correlation by excluding resistances (resistances er1 and er2 in FIG. 9) whose errors (hereinafter referred to as resistance estimation errors) from the resistances calculated by the resistance calculation unit 32 and the resistance estimation curve Lr are equal to or greater than a first threshold, and capacities (capacities ec1 in FIG. 9) whose errors (hereinafter referred to as capacity estimation errors) from the capacity estimation curve Lc are equal to or greater than a second threshold, from among the resistances calculated by the resistance calculation unit 32. The first threshold and the second threshold are determined, for example, as follows. That is, as shown in FIG. 10A, assuming that the resistance estimation error appears according to a normal distribution and the standard deviation with respect to the average of the resistance estimation error is σ1, the first threshold is, for example, 2σ1. The first threshold may be 3σ1. As shown in FIG. 10B, assuming that the capacitance estimation error appears according to a normal distribution and the standard deviation with respect to the average of the capacitance estimation error is σ2, the second threshold is, for example, 2σ2. The second threshold may be 3σ2.

[0075] In the example of FIG. 11, the correlation determination unit 41 determines the correlation (i.e., the approximate curve Le) by excluding the resistance R1 and capacity Q1 of the storage battery 21 during the first use of the UPS 11 and the resistance R3 and capacity Q3 of the storage battery 21 during the third use of the UPS 11 from the resistance calculated by the resistance calculation unit 32 and the capacity calculated by the capacity calculation unit 33.

[0076] As described above, in this embodiment, the correlation determining unit 41 determines the resistance estimation curve Lr based on the resistance calculated by the resistance calculating unit 32, and determines the capacity estimation curve Lc based on the capacity calculated by the capacity calculating unit 33. The correlation determining unit 41 determines the correlation by excluding resistances calculated by the resistance calculating unit 32, the error of which from the resistance estimation curve Lr is equal to or greater than a first threshold, and capacitances calculated by the capacity calculating unit 33, the error of which from the capacity estimation curve Lc is equal to or greater than a second threshold. This improves the accuracy of diagnosis of the UPS 11.

[0077] Embodiment 4 Next, a description will be given of a degradation diagnosis device, a degradation diagnosis system, and a degradation diagnosis method according to embodiment 4. The degradation diagnosis device according to this embodiment has a basic configuration similar to that of embodiment 3, so the description will focus on the differences.

[0078] In this embodiment, the correlation determining unit 41 weights the resistance calculated by the resistance calculating unit 32 and the capacitance calculated by the capacitance calculating unit 33 based on the capacitance-resistance error and the capacitance estimation error, and determines the correlation. i The capacity (actual measurement value) calculated by the capacity calculation unit 33 during the i-th use of the UPS 11 is Q i Then, Qx in the above formula (4) is changed to Q (ri) Then, it is expressed by the following formula (6).

[0079]

number

[0080] That is, from equation (4), the error E can be expressed by the following equation (7).

[0081]

number

[0082] In addition, the weight w i is the variance of the error E, σ 2Using this, it is expressed by the following formula (8).

[0083]

number

[0084] The correlation determining unit 41 determines the error E and the weight w i The coefficient A and the constant B in the formula (4) are determined so that the sum of products of the above formula (6) is minimized. That is, the correlation determination unit 41 weights the resistance calculated by the resistance calculation unit 32 and the capacity calculated by the capacity calculation unit 33 by calculating the coefficients A and B so that the above formula (6) is minimized. The correlation determination unit 41 determines the correlation (i.e., the approximation curve Le) based on the weighted resistance and capacity. Note that the weighting may be performed over the entire pre-estimation interval P2, or may be performed only on the latter half of the pre-estimation interval P2. When the weighting is performed only on the latter half of the pre-estimation interval P2, the accuracy of the deterioration diagnosis can be improved when the resistance and capacity of the storage battery 21 change significantly in the latter half of the life of the UPS 11 where the deterioration of the UPS 11 progresses.

[0085] As described above, in this embodiment, the correlation determination unit 41 determines a resistance estimation curve Lr based on the resistance calculated by the resistance calculation unit 32, and determines a capacity estimation curve Lc based on the capacity calculated by the capacity calculation unit 33. The correlation determination unit 41 weights the resistance calculated by the resistance calculation unit 32 and the capacity calculated by the capacity calculation unit 33 based on the error between the resistance calculated by the resistance calculation unit 32 and the resistance estimation curve Lr and the error between the capacity calculated by the capacity calculation unit 33 and the capacity estimation curve Lc, and determines the correlation. This improves the diagnosis accuracy of the UPS 11.

[0086] Embodiment 5. Next, a description will be given of a degradation diagnosis device, a degradation diagnosis system, and a degradation diagnosis method according to embodiment 5. The degradation diagnosis device according to this embodiment has a basic configuration similar to that of embodiment 1, so the description will focus on the differences.

[0087] In this embodiment, the capacity maintenance rate calculation unit 43 calculates the life of the UPS 11 based on the calculated capacity maintenance rate. 13 is a graph showing the transition of the capacity maintenance rate of the storage battery 21 with the horizontal axis representing time to the power of 0.5. As shown in FIG. 13, when the horizontal axis represents time to the power of 0.5, the capacity maintenance rate of the storage battery 21 has a tendency to decrease linearly. That is, when the elapsed time from the initial state is t, the capacity maintenance rate M can be expressed by the following formula (9). Note that C and D are constants and are determined based on the capacity maintenance rate calculated by the capacity maintenance rate calculation unit 43.

[0088]

number

[0089] From the above formula (9), the life of UPS11 is end is expressed by the following formula (10).

[0090]

number

[0091] For example, assuming that the life of the UPS 11 is when the capacity maintenance rate drops to 60(%), the life of the UPS 11 can be reduced by setting M=60(%) in the above formula (10). end can be calculated.

[0092] It should be noted that the embodiments may be combined, modified, or omitted as appropriate.

[0093] For example, in the above embodiment, a case has been described in which deterioration of the UPS 11 is diagnosed, but the deterioration diagnosis device, deterioration diagnosis system, and deterioration diagnosis method disclosed herein can be applied to diagnosing deterioration of a storage battery system other than a UPS.

[0094] The above-mentioned control unit 36 ​​has a computer system therein. Then, a program for realizing the functions of each component included in the above-mentioned data center 1 may be recorded on a computer-readable recording medium, and the program recorded on the recording medium may be read into and executed by a computer system to perform the above-mentioned processing in the control unit 36. Also, hardware other than the control unit 36 ​​may perform the above-mentioned processing.

[0095] Here, "loading the program recorded on the recording medium into a computer system and executing it" includes installing the program into a computer system. The "computer system" here includes the OS and hardware such as peripheral devices.

[0096] Furthermore, a "computer system" may include multiple computer devices connected via a network including the Internet or communication lines such as a WAN, LAN, or leased line. Furthermore, a "computer-readable recording medium" refers to portable media such as flexible disks, optical magnetic disks, ROMs, and CD-ROMs, and storage devices such as hard disks built into a computer system. In this way, the recording medium storing the program may be a non-transitory recording medium such as a CD-ROM.

[0097] The recording medium also includes a recording medium installed inside or outside and accessible from a distribution server to distribute the program. The program may be divided into a plurality of parts, each of which may be downloaded at a different timing and then combined in each configuration of the data center 1, and each of the divided programs may be distributed by a different distribution server. Furthermore, the "computer-readable recording medium" includes a recording medium that holds a program for a certain period of time, such as a volatile memory (RAM) in a computer system that becomes a server or a client when a program is transmitted via a network. The above program may also be a recording medium for realizing part of the above-mentioned functions. Furthermore, the recording medium may be a so-called difference file (difference program) that can realize the above-mentioned functions in combination with a program already recorded in the computer system. [Explanation of symbols]

[0098] 1...data center, 2...power system, 11...UPS (battery storage system), 12...server / storage (load), 15...pulse generator, 16...calculation unit, 17...display unit, 21...battery, 22...BMU (battery storage control unit), 25...switch, 26...pulse generator, 31...acquisition unit, 32...resistance calculation unit, 33...capacity calculation unit, 34...storage unit, 35...deterioration amount estimation unit, 36...control unit, 41...correlation determination unit, 42...capacity estimation unit, 43...capacity maintenance rate calculation unit

Claims

1. A deterioration diagnosis device for diagnosing deterioration of a storage battery system, A resistance calculation unit that calculates a resistance of a storage battery of the storage battery system; a capacity calculation unit that calculates a capacity of the storage battery when the storage battery system is in use; a correlation determination unit that determines a correlation between a resistance and a capacity of the storage battery based on the resistance calculated by the resistance calculation unit and the capacity calculated by the capacity calculation unit; a capacity estimation unit that estimates a capacity of the storage battery in a capacity estimation section between an x-1th use and an xth use of the storage battery system based on the correlation, where x is an integer equal to or greater than 3; Equipped with The resistance calculation unit calculates the resistance a plurality of times in a pre-estimation interval up to the x-1th use of the storage battery system, and calculates the resistance in the capacity estimation interval; the correlation determination unit determines the correlation based on the resistance calculated by the resistance calculation unit in the pre-estimation section and the capacity calculated by the capacity calculation unit during at least two uses among a first use to an x−1th use of the storage battery system; the capacity estimation unit estimates a capacity of the storage battery based on the correlation and the resistance calculated by the resistance calculation unit in the capacity estimation section; A storage battery whose resistance is calculated by the resistance calculation unit and whose capacity is calculated by the capacity calculation unit in the pre-estimation interval is the same as a storage battery whose capacity is estimated by the capacity estimation unit in the capacity estimation interval. Deterioration diagnosis device.

2. The present invention further includes a pulse generating device having a pulse generating unit that generates a pulse signal and a switch that is switched between an on state and an off state by the pulse signal, and discharging the storage battery by switching the switch, The resistance calculation unit calculates the resistance of the storage battery based on measurement results of a current and a voltage of the storage battery when the storage battery is discharged by the pulse generating device in the capacity estimation section. The deterioration diagnosis device according to claim 1 .

3. A capacity maintenance rate calculation unit that calculates a capacity maintenance rate based on the capacity of the storage battery estimated by the capacity estimation unit, The deterioration diagnostic device according to claim 1 or 2.

4. A display unit on which the estimation result of the capacity of the storage battery by the capacity estimation unit is displayed, The deterioration diagnostic device according to claim 1 or 2.

5. the correlation determination unit determines the correlation based on the resistance calculated by the resistance calculation unit in the pre-estimation section and the capacity calculated by the capacity calculation unit during at least two uses among an n-th use to an x−1-th use of the storage battery system; n is an integer of 2 or more, and x is an integer of 4 or more; The deterioration diagnostic device according to claim 1 or 2.

6. the correlation determination unit determines a resistance estimation curve based on the resistance calculated by the resistance calculation unit, determines a capacitance estimation curve based on the capacitance calculated by the capacitance calculation unit, and determines the correlation by excluding, from the resistances calculated by the resistance calculation unit, resistances having an error from the resistance estimation curve that is equal to or greater than a first threshold value, and capacitances having an error from the capacitance estimation curve that is equal to or greater than a second threshold value, from the capacitances calculated by the capacitance calculation unit. The deterioration diagnostic device according to claim 1 or 2.

7. the correlation determination unit determines a resistance estimation curve based on the resistance calculated by the resistance calculation unit, determines a capacitance estimation curve based on the capacitance calculated by the capacitance calculation unit, and weights the resistance calculated by the resistance calculation unit and the capacitance calculated by the capacitance calculation unit based on an error between the resistance calculated by the resistance calculation unit and the resistance estimation curve and an error between the capacitance calculated by the capacitance calculation unit and the capacitance estimation curve, thereby determining the correlation. The deterioration diagnostic device according to claim 1 or 2.

8. The storage battery system is connected to a load via a switch, and when the switch is in an on state, power is supplied from the storage battery system to the load; When the storage battery system is not in use, power is not supplied from the storage battery system to the load, and power is supplied from a power grid to the load; When the storage battery system is in use, power is not supplied from the power grid to the load, and power is supplied from the storage battery system to the load. The deterioration diagnostic device according to claim 1 or 2.

9. The degradation diagnosis device according to claim 1 or 2, The storage battery system; Equipped with The storage battery system includes a storage battery and a storage battery control unit that controls the storage battery. Deterioration diagnosis system.

10. A degradation diagnosis method for diagnosing degradation of a storage battery system, comprising: A resistance calculation step of calculating a resistance of a storage battery of the storage battery system; A capacity calculation step of calculating a capacity of the storage battery during use of the storage battery system; a correlation determination step of determining a correlation between the resistance and the capacity of the storage battery based on the resistance calculated in the resistance calculation step and the capacity calculated in the capacity calculation step; a capacity estimation step of estimating a capacity of the storage battery in a capacity estimation section between an x-1th use and an xth use of the storage battery system based on the correlation, where x is an integer equal to or greater than 3; Equipped with In the resistance calculation step, the resistance is calculated a plurality of times in a pre-estimation section up to the x-1th use of the storage battery system, and the resistance is calculated in the capacity estimation section; In the correlation determination step, the correlation is determined based on the resistance calculated in the resistance calculation step in the pre-estimation section and the capacity calculated in the capacity calculation step at least two uses among a first use to an x−1th use of the storage battery system; In the capacity estimation step, a capacity of the storage battery is estimated based on the correlation and the resistance calculated in the resistance calculation step in the capacity estimation section; A storage battery whose resistance is calculated by the resistance calculation step and whose capacity is calculated by the capacity calculation step in the pre-estimation section is the same as a storage battery whose capacity is estimated by the capacity estimation step in the capacity estimation section. Deterioration diagnosis method.

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