1
FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10, Rule 13]
DEGRADATION DIAGNOSIS DEVICE, DEGRADATION DIAGNOSIS SYSTEM,
AND DEGRADATION DIAGNOSIS METHOD
MITSUBISHI ELECTRIC CORPORATION, A CORPORATION ORGANISED AND
EXISTING UNDER THE LAWS OF JAPAN, WHOSE ADDRESS IS 7-3,
MARUNOUCHI 2-CHOME, CHIYODA-KU, TOKYO 1008310, JAPAN
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE
INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.
SPECIFICATION
2
DESCRIPTION
Technical Field
[0001]
The present disclosure relates to a degradation diagnosis device, a degradation
diagnosis system, and a degradation diagnosis method.5
Background Art
[0002]
In a data center or the like, a storage battery system as an emergency power supply
is provided to supply electric power to each device in an emergency when electric supply
from a power system is cut off. For example, an uninterruptible power supply (UPS) is10
used as the storage battery system.
[0003]
To reliably supply electric power from the storage battery system to each device
of the data center in an emergency, it is necessary to diagnose the degradation of the storage
battery system and grasp the replacement time of the storage battery system. Patent15
Document 1 discloses a capacity estimation method and a degradation diagnosis device of
a battery pack as an emergency power supply.
Citation List
Patent Documents
[0004]20
Patent Document 1: Japanese Unexamined Patent Application, First Publication
No. 2003-22844
3
Summary of Invention
Problem to be Solved by the Invention
[0005]
To diagnose the degradation of the storage battery system, it is considered to stop
the data center and forcibly discharge the storage battery system to check the capacity of5
the storage battery of the storage battery system. In this case, it is necessary to stop the
data center for a long time, and there is a possibility of hindering the operation of the data
center. In addition, the timing of performing the degradation diagnosis of the storage
battery system is limited.
[0006]10
In Patent Document 1, internal resistances and capacities of at least two single
batteries among a plurality of single batteries constituting a battery pack are measured, and
a linear expression representing a correlation between the internal resistance and the
capacity is determined based on the measurement results. The capacity of the battery
pack is estimated by introducing the internal resistance of the other single battery into this15
linear expression. In the structure of Patent Document 1, it is necessary to acquire data
for degradation diagnosis such as a correlation between the internal resistance and the
capacity of the storage battery in advance.
[0007]
The present disclosure has been made to solve the above-described issues, and an20
object of the present disclosure is to provide a degradation diagnosis device, a degradation
diagnosis system, and a degradation diagnosis method capable of performing degradation
diagnosis of a storage battery system at any timing without acquiring data for degradation
diagnosis in advance.
Means to Solve the Problem25
4
[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 configured to calculate a resistance of a storage
battery of the storage battery system, a capacity calculation unit configured to calculate a5
capacity of the storage battery during use of the storage battery system, a correlation
determination unit configured to determine a correlation between the resistance and the
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 configured to estimate the capacity of the storage battery in a capacity10
estimation interval between an (x-1)-th use and an x-th use of the storage battery system
based on the correlation, where x is an integer of 3 or more, in which the resistance
calculation unit calculates the resistance a plurality of times in a pre-estimation interval up
to the (x-1)-th use of the storage battery system and calculates the resistance in the capacity
estimation interval, the correlation determination unit determines the correlation based on15
the resistance calculated by the resistance calculation unit in the pre-estimation interval
and the capacity calculated by the capacity calculation unit in at least two uses of the
storage battery system among a first use to the (x-1)-th use, 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.20
[0009]
A degradation diagnosis system according to the present disclosure includes the
degradation diagnosis device and the storage battery system, in which the storage battery
system includes a storage battery and a storage battery control unit configured to control
the storage battery.25
5
[0010]
A degradation diagnosis method according to the present disclosure is a
degradation diagnosis method for diagnosing degradation of a storage battery system, and
includes 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 storage5
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, and a capacity estimation step of estimating the
capacity of the storage battery in a capacity estimation interval between an (x-1)-th use and10
an x-th use of the storage battery system based on the correlation, where x is an integer of
3 or more, in which in the resistance calculation step, the resistance is calculated a plurality
of times in a pre-estimation interval up to the (x-1)-th 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 the15
resistance calculation step in the pre-estimation interval and the capacity calculated in the
capacity calculation step in at least two uses of the storage battery system among a first
use to the (x-1)-th use, and 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.20
Effects 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
capable of performing degradation diagnosis of a storage battery system at any timing25
6
without acquiring data for degradation diagnosis in advance.
Brief Description of Drawings
[0012]
[FIG. 1A] A diagram showing the overall configuration of a data center according
to a first embodiment in a normal time.5
[FIG. 1B] A diagram showing an overall configuration of the data center
according to the first embodiment in an emergency.
[FIG. 2] A block diagram of a UPS, an operation unit, and a display unit according
to the first embodiment.
[FIG. 3] A graph showing a transition of an SOC of a storage battery according to10
a change in a usage state of the UPS.
[FIG. 4] A diagram showing calculation of the resistance and the capacity of a
storage battery and estimation of the capacity of the storage battery by an operation unit
according to the first embodiment.
[FIG. 5A] A graph showing an example of a voltage curve in a case where the15
UPS is used from an upper limit voltage to a lower limit voltage.
[FIG. 5B] A graph showing an example of a current curve in a case where the UPS
is used from the upper limit voltage to the lower limit voltage.
[FIG. 5C] A graph showing an example of an SOC curve in a case where the UPS
is used from the upper limit voltage to the lower limit voltage.20
[FIG. 6] A diagram showing estimation of the capacity of a storage battery by the
operation unit according to the first embodiment.
[FIG. 7] A flowchart showing an example of processing executed by the
degradation diagnosis device according to the first embodiment.
[FIG. 8] A diagram showing estimation of the capacity of a storage battery by the25
7
operation unit according to a second embodiment.
[FIG. 9] A diagram showing calculation of the resistance and the capacity of a
storage battery and estimation of the capacity of the storage battery by an operation unit
according to a third embodiment.
[FIG. 10A] A graph showing the normal distribution of a resistance estimation5
error.
[FIG. 10B] A graph showing the normal distribution of a capacity estimation error.
[FIG. 11] A diagram showing estimation of the capacity of a storage battery by
the operation unit according to the third embodiment.
[FIG. 12] A diagram showing estimation of the capacity of a storage battery by10
the operation unit according to a fourth embodiment.
[FIG. 13] A graph showing a transition of the capacity retention ratio of a storage
battery.
Description of Embodiments
[0013]15
Hereinafter, embodiments of the present disclosure will be described with
reference to drawings. The scope of the present disclosure is not limited to the following
embodiments, and can be changed in any way within the scope of technical ideas of the
present disclosure.
[0014]20
First embodiment.
First, a degradation diagnosis device, a degradation diagnosis system, and a
degradation diagnosis method according to a first embodiment will be described. The
degradation diagnosis device according to the present embodiment is installed in the data
center 1.25
8
[0015]
FIGs. 1A and 1B are diagrams showing the overall configuration of a data center
1. As shown in FIGs. 1A and 1B, the data center 1 is constituted by an uninterruptible
power supply (UPS) 11, a server storage 12, an AC/DC converter 13, a DC/DC converter
14, a pulse generation device 15, an operation unit 16, a display unit 17, and the like. The5
data center 1 is connected to the power system 2. The UPS 11 is an example of a storage
battery system. The pulse generation device 15, the operation unit 16, and the display
unit 17 constitute a degradation diagnosis device that diagnoses degradation of the UPS 11.
The UPS 11, the pulse generation device 15, the operation unit 16, and the display unit 17
constitute a degradation diagnosis system.10
[0016]
The server storage 12 is a device for storing data for a long period of time. The
server storage 12 is used in a device such as a computer or data communication. The
server storage 12 is connected to the power system 2 via the AC/DC converter 13 and the
DC/DC converter 14. The server storage 12 is connected to the UPS 11 via a DC/DC15
converter 14. In a normal time, the server storage 12 is supplied with power by the power
system 2. In this case, the UPS 11 is not used and is in a standby state. In an emergency
in which the electric supply from the power system 2 to the server storage 12 is cut off, the
server storage 12 is supplied with power by the UPS 11. Hereinafter, the normal time
will also be referred to as a time when the UPS 11 is not in use. The emergency is also20
referred to as a case where the UPS 11 is in use.
[0017]
The UPS 11 includes a storage battery 21 and a battery management unit (BMU)
22 (storage battery control unit).
25
9
[0018]
The storage battery 21 is a secondary battery that is capable of charging and
discharging. The storage battery 21 is, for example, a lithium ion battery, a nickel
hydrogen battery, or a lead storage battery.
The BMU 22 controls charging and discharging of the storage battery 21. The5
BMU 22 has a protection function of preventing overcharging, overdischarging,
overvoltage, overcurrent, temperature abnormality, and the like of the storage battery 21
based on the upper and lower limit voltages, the maximum charging and discharging
current, the maximum cell temperature, and the like of the storage battery 21. The BMU
22 has a state monitoring function of the storage battery 21, such as voltage measurement,10
current measurement, power measurement, temperature measurement, full charge
management, and remaining capacity management of the storage battery 21. The UPS
11 is provided with a measurement sensor that measures a voltage, a current, and a
temperature of the storage battery 21. The measurement sensor includes, for example, a
voltage probe for measuring a voltage of the storage battery 21, a shunt resistor type or a15
hall type current sensor for measuring a current of the storage battery 21, and a
thermocouple for measuring a temperature of the storage battery 21.
[0019]
The UPS 11 is connected to the power system 2. In a normal time (that is, in a
case where the UPS 11 is not in use), the UPS 11 is constantly charged by the power system20
2.
[0020]
FIG. 3 is a diagram showing a transition of a state of charge (SOC) of the storage
battery 21 according to a change in a usage state of the UPS 11. A case where the SOC
is 0 (%) indicates that the storage battery 21 is in a completely discharged state, and a case25
10
where the SOC is 100 (%) 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 a region A1
in which the SOC is retained at 100 (%), a region A2 in which the SOC decreases from
100 (%) to X (%), and a region A3 in which the SOC recovers from X (%) to 100 (%).5
[0022]
The region A1 corresponds to a case where the UPS 11 is not in use. In this case,
the storage battery 21 is not used for electric supply to the server storage 12, and is charged
by the power system 2 to retain a fully charged state.
The region A2 corresponds to a case where the UPS 11 is in use. In this case,10
the electric supply from the power system 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 is decreased.
The region A3 corresponds to a case where the UPS 11 is not in use. In the
region A3, the power system 2 is restored, and the electric power supply to the server15
storage 12 is switched from the UPS 11 to the power system 2. The storage battery 21 is
charged by the power system 2 to return to a fully charged state.
The regions A1 to A3 are repeated depending on the use of the UPS 11.
[0023]
It is noted that in the data center 1, in a case where the power system 2 is restored,20
since electric supply to the server storage 12 is switched from the UPS 11 to the power
system 2, use of the UPS 11 is often terminated before the storage battery 21 is completely
discharged (that is, before the SOC is lowered to 0 (%)). FIG. 3 shows a case where the
SOC of the storage battery 21 is decreased to X (%) in the region A2, but the value of X
varies depending on the time during which the electric supply from the power system 2 to25
11
the server storage 12 is cut off. In addition, in the data center 1, since the UPS 11 is used
only in an emergency, the UPS 11 is used infrequently and often stands in a fully charged
state (that is, in the area A1).
[0024]
The AC/DC converter 13 converts the alternating current power from the power5
system 2 into direct current power.
The DC/DC converter 14 converts the voltage of the electric power from the UPS
11 into a voltage corresponding to the server storage 12. The DC/DC converter 14
converts the voltage of the electric power from the power system 2 into a voltage
corresponding to the server storage 12.10
[0025]
The pulse generation device 15 is provided between the UPS 11 and the DC/DC
converter 14. The pulse generation device 15 switches on and off the conduction of the
current between the UPS 11 and the DC/DC converter 14 to switch on and off the
discharging from the storage battery 21 of the UPS 11 to the server storage 12. The pulse15
generation device 15 includes a switch 25 and a pulse generation unit 26.
[0026]
The pulse generation unit 26 generates a pulse signal for switching between an on
state and an off state of the switch 25.
[0027]20
The switch 25 is switched between an on state and an off state by the pulse signal
from the pulse generation unit 26 to switch on and off the conduction of the current
between the UPS 11 and the DC/DC converter 14.
[0028]
In a case where the switch 25 is in an on state, the discharge occurs from the UPS25
12
11 to the server storage 12. In a normal time shown in FIG. 1A, in a case where the switch
25 is in an on state, the server storage 12 is supplied with power from both the power
system 2 and the UPS 11. In the emergency shown in FIG. 1B, the switch 25 is always
in an on state, and the server storage 12 is supplied with power from the UPS 11.
In a case where the switch 25 is in an off state, the current is blocked between the5
UPS 11 and the DC/DC converter 14, and the discharge does not occur from the UPS 11
to the server storage 12.
[0029]
It is noted that the pulse generation device 15 is only required to be allowed to
switch on and off of the discharge from the UPS 11 to the server storage 12, for example,10
may be constituted by a resistor and a switch. In this case, the resistor is, for example, a
variable resistor, and the on and off of the discharge from the UPS 11 to the server storage
12 may be switched by switching the resistance value in a pulsed manner.
[0030]
The operation unit 16 estimates the capacity of the storage battery 21 in the15
capacity estimation interval P1 between the (x-1)-th use and the x-th use of the UPS 11,
and calculates the capacity retention ratio of the storage battery 21 based on the estimated
capacity of the storage battery 21. It is noted that x is an integer of 3 or more. The
capacity estimation interval P1 corresponds to a case where the UPS 11 is not in use. In
addition, in the following description, an interval from the initial state to the (x-1)-th use20
of the UPS 11 is referred to as a pre-estimation interval P2. The pre-estimation interval
P2 includes the (x-1)-th use of the UPS 11.
[0031]
FIG. 2 is a block diagram of the UPS 11, the operation unit 16, and the display
unit 17. As shown in FIG. 2, the operation unit 16 includes an acquisition unit 31, a25
13
resistance calculation unit 32, a capacity calculation unit 33, a storage unit 34, a
degradation 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 degradation amount estimation unit 35 by5
executing a program by a central processing unit (CPU) or the like. In addition, the
control unit 36 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 ordering
the storage battery 21 to discharge. It is noted that the control unit configured to control
the pulse generation device 15 may be provided separately from the control unit 36.10
[0033]
The acquisition unit 31 acquires the parameter of the storage battery 21 to be used
for estimating the capacity of the storage battery 21 from the UPS 11. 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 parameter of the storage battery15
21 from the BMU 22. The acquisition unit 31 may acquire the parameter of the storage
battery 21 from the measurement sensor provided in the UPS 11 without through the BMU
22.
[0034]
The resistance calculation unit 32 calculates the resistance of the storage battery20
21 based on the parameter 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 response of the current and the voltage of the storage battery 21 in
a case where 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 125
14
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 Expression (1) below
according to Ohm’s law. In Expression (1), I is a current of the storage battery 21 in a
case where the storage battery 21 is discharged, and V is a voltage of the storage battery5
21 in a case where the storage battery 21 is discharged. The OCV is an open circuit
voltage of the storage battery 21. The open circuit voltage of the storage battery 21 is a
voltage in a case where the storage battery 21 is left to stand in a no-load state and the
voltage is not fluctuated.
[0036]10
[0037]
The resistance of the storage battery 21 changes depending on the temperature of
the storage battery 21. Therefore, it is preferable that the temperature of the storage
battery 21 in a case of calculating the resistance of the storage battery 21 is constant. In15
a case where the temperature of the storage battery 21 changes, the resistance calculation
unit 32 may correct the resistance of the storage battery 21 according to the change in the
temperature of the storage battery 21. For example, a reference temperature may be
predetermined, and the resistance calculation unit 32 may correct the resistance of the
storage battery 21 according to a difference between the temperature of the storage battery20
21 and the reference temperature.
[0038]
In FIG. 4, the resistance calculated by the resistance calculation unit 32 is
15
represented by a triangle. As shown in FIG. 4, the resistance calculation unit 32
calculates the resistance of the storage battery 21 a plurality of 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]5
The pre-estimation interval P2 includes a region A2 corresponding to a case where
the UPS 11 is in use and regions A1 and A3 corresponding to a case where the UPS 11 is
not in use. The resistance calculation unit 32 calculates the resistance of the storage
battery 21 in the region A2 and the region A1 in the pre-estimation interval P2. In the
region A2 of the pre-estimation interval P2, the resistance calculation unit 32 calculates10
the resistance of the storage battery 21 according to the response of the current and the
voltage of the storage battery 21 in a case where the server storage 12 is supplied with
power from the UPS 11. In the region A1 of the pre-estimation interval P2, the resistance
calculation unit 32 calculates the resistance of the storage battery 21 according to the
response of the current and the voltage of the storage battery 21 in a case where the storage15
battery 21 is discharged for a predetermined discharge time by the pulse generation device
15. In the region A2, the resistance of the storage battery 21 may not be calculated.
[0040]
The capacity calculation unit 33 calculates the capacity of the storage battery 21
in a case where the UPS 11 is in use, according to the parameter of the storage battery 2120
acquired by the acquisition unit 31. The calculated capacity is stored in the storage unit
34.
In FIG. 4, the capacity calculated by the capacity calculation unit 33 is represented
by a black circle. As shown in FIG. 4, the capacity calculation unit 33 calculates the
capacity of the storage battery 21 each time the UPS 11 is used.25
16
[0041]
FIG. 5A is a graph showing a voltage curve in a case where the UPS 11 is used
from the upper limit voltage VU to the lower limit voltage VL. 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, a time point t1 is a time point at which the use of the UPS 11 is5
started (that is, a time point at which the use of the UPS 11 is switched from normal time
to emergency), a time point t2 is a time point at which the current value is changed from I1
to I2 because of a change in the use status of the server storage 12 that is the load, and a
time point t3 is a time point at which the use of the UPS 11 is ended (that is, a time point
at which the use of the UPS 11 is switched from emergency to normal time). As shown10
in FIGs. 5A to 5C, the voltage, the current, and the SOC of the storage battery 21 are related
to each other.
[0042]
The capacity of the storage battery 21 can be calculated by integrating the current
of the storage battery 21. For example, in a case where the SOC of the storage battery 2115
changes from 100 (%) to 0 (%) by using the UPS 11, the capacity Q of the storage battery
21 is calculated as in Expression (2). Specifically, the capacity Q of the storage battery
21 is obtained by integrating the current I in a case where the SOC changes from 100 (%)
to 0 (%). The unit of the capacity Q of the storage battery 21 is Ah or Wh.
[0043]20
17
[0044]
Here, since the UPS 11 is temporarily used when the power system 2 is cut off,
the UPS 11 is rarely used from a fully charged state to a completely discharged state at a
constant current or a constant voltage. In a case where the UPS 11 is in use, in a case
where the UPS 11 is not used to the completely discharged state and the SOC changes from5
a (%) to b (%), the capacity Q of the storage battery 21 is calculated as Expression (3).
Specifically, the current I of the partial discharge in a case where the SOC changes from a
(%) to b (%) is integrated. The capacity Q is obtained by multiplying the integrated result
by 100/(a - b).
[0045]10
[0046]
The capacity of the storage battery 21 changes depending on the temperature of
the storage battery 21. Therefore, it is preferable that the temperature of the storage
battery 21 in a case of calculating the capacity of the storage battery 21 is constant. In a15
case where the temperature of the storage battery 21 changes, the capacity calculation unit
33 may correct the capacity of the storage battery 21 according to the change in the
temperature of the storage battery 21. For example, a reference temperature may be
predetermined, and the capacity calculation unit 33 may correct the capacity of the storage
battery 21 according to a difference between the temperature of the storage battery 21 and20
the reference temperature.
[0047]
The resistance calculated by the resistance calculation unit 32 and the capacity
18
calculated by the capacity calculation unit 33 are stored in the storage unit 34 as past data.
The storage unit 34 is formed by, for example, a non-volatile or volatile semiconductor
memory such as a random access memory (RAM), a read only memory (ROM), a flash
memory, an erasable programmable read only memory (EPROM), or an electrically
erasable and programmable ROM (EEPROM).5
[0048]
The degradation amount estimation unit 35 estimates the degradation 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 degradation amount estimation unit 35 includes a10
correlation determination unit 41, a capacity estimation unit 42, and a capacity retention
ratio calculation unit 43.
[0049]
The correlation determination unit 41 determines a correlation between the
resistance and the capacity of the storage battery 21 based on the resistance of the storage15
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 showing the estimation of the capacity of the storage battery
21 by the operation unit 16. In FIG. 6, a vertical axis indicates the capacity of the storage20
battery 21, and a horizontal axis indicates the resistance of the storage battery 21. Q1,
Q2, ..., and Qx-1 each indicate the capacity of the storage battery 21 calculated by the
capacity calculation unit 33 in the first use, the second use, ..., and (x-1)th use of the UPS
11. R1, R2, ..., and Rx-1 each indicate the resistance of the storage battery 21 calculated
by the capacity calculation unit 33 in the first use, the second use, ..., and (x-1)th use of the25
19
UPS 11. In a case where the resistance of the storage battery 21 is not calculated in the
region A2, the resistances R1, R2, ..., and 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 region 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, in a case where the UPS5
11 is degradated by use and the capacity of the storage battery 21 is decreased, the
resistance of the storage battery 21 is increased.
[0051]
The correlation determination unit 41 determines the correlation between the
resistance and the capacity of the storage battery 21 by obtaining the approximate curve10
Le representing the correlation between the resistance and the capacity of the storage
battery 21. For example, in the example of FIG. 6, the approximate curve Le is
represented by Expression (4) as a linear function. It is noted that the approximate curve
Le may be any function that can indicate the correlation between the resistance and the
capacity of the storage battery 21, and is not limited to the linear function.15
[0052]
[0053]
The correlation determination unit 41 determines the coefficient A and the
constant B in Expression (4) based on the resistances R1, R2, ..., and Rx-1 of the storage20
battery 21 calculated by the resistance calculation unit 32 and the capacities Q1, Q2, ...,
and 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 among
20
the capacities Q1, Q2, ..., and Qx-1 of the storage battery 21 calculated by the capacity
calculation unit 33. To improve the 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 among the capacities Q1, Q2, ..., and Qx-1 of the storage battery 21 calculated
by the capacity calculation unit 33.5
[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 by the
resistance calculation unit 32 in the capacity estimation interval P1. Specifically, the10
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 by the resistance calculation unit 32 in the capacity estimation interval P1 into
Expression (4).
[0055]15
The capacity retention ratio calculation unit 43 calculates the capacity retention
ratio of the storage battery 21 based on the capacity Q of the storage battery 21. In a case
where the capacity retention ratio of the storage battery 21 in the initial state until the first
use of the UPS 11 is set to 100 (%) (that is, in a case where the degradation amount of the
storage battery 21 is set to 0 (%)), the capacity retention ratio M (%) is represented by20
Expression (5). It is 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, ..., and Rx-1 of the storage battery 21 calculated by the resistance calculation unit
32 and the capacities Q1, Q2, ..., and Qx-1 of the storage battery 21 calculated by the
capacity calculation unit 33.25
21
[0056]
[0057]
In a case where the capacity retention ratio calculated by the capacity retention
ratio calculation unit 43 is equal to or less than the threshold value, it is determined that5
the life of the UPS 11 has arrived. The threshold value may be, for example, 80 (%) or
60 (%). It is noted that the degradation amount estimation unit 35 may calculate the life
of the UPS 11, the replacement time of the UPS 11, or the like based on the capacity
retention ratio calculated by the capacity retention ratio calculation unit 43.
[0058]10
The display unit 17 is a display device such as a display. The display unit 17
displays a parameter of the storage battery 21, the capacity of the storage battery 21, the
capacity retention ratio of the storage battery 21, and the like. In a case where the
degradation 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 11.15
[0059]
FIG. 7 is a flowchart showing an example of a flow of processing of the
degradation diagnosis method of the UPS 11.
[0060]
First, it is determined whether or not the UPS 11 is being used (Step S101).20
[0061]
In a case where the UPS 11 is used (Step S101: YES), the discharge from the UPS
101 to the server storage 12 as the load is performed (Step S102).
22
The acquisition unit 31 acquires the parameter of the storage battery 21 in a case
where the UPS 11 is in use (Step S103).
The resistance calculation unit 32 calculates the resistance of the storage battery
21 based on the parameter of the storage battery 21 acquired in Step S103 (Step S104).
Step S104 corresponds to a resistance calculation step. The calculated resistance of the5
storage battery 21 is stored in the storage unit 34.
The capacity calculation unit 33 calculates the capacity of the storage battery 21
based on the parameter of the storage battery 21 acquired in Step S103 (Step S105). Step
S105 corresponds to the capacity calculation step. The calculated capacity of the storage
battery 21 is stored in the storage unit 34.10
Thereafter, the processing proceeds to Step S110.
[0062]
In a case where the UPS 11 is not in use (Step S101: NO), the control unit 36
makes the pulse generation unit 26 of the pulse generation device 15 generate a pulse signal,
thereby the storage battery 21 is discharged for a discharge time (Step S106).15
The acquisition unit 31 acquires the parameter of the storage battery 21 in a case
where the storage battery 21 is discharged by the pulse generation device 15 (Step S107).
The resistance calculation unit 32 calculates the resistance of the storage battery
21 based on the parameter of the storage battery 21 acquired in Step S107 (Step S108).
Step S108 corresponds to the resistance calculation step.20
The degradation amount estimation unit 35 determines a correlation between the
resistance and the 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).25
23
Step S109 corresponds to a correlation determination step and a capacity estimation step.
Thereafter, the processing proceeds to Step S110.
[0063]
Thereafter, the control unit 36 determines whether or not to end the degradation
diagnosis of the UPS 11 (Step S110). In a case where the determination result in Step5
S110 is YES, the processing ends. In a case where the determination result in Step S110
is NO, the process returns to Step S101. For example, a case where it is preferable to
continue the estimation of the capacity of the storage battery 21 is determined as Step S110:
NO. A case where the state of the storage battery 21 can be sufficiently grasped is
determined as Step S110: YES, and the processing ends.10
[0064]
As described above, the degradation diagnosis device according to the present
embodiment includes the resistance calculation unit 32 that calculates the resistance of the
storage battery 21 of the UPS 11, the capacity calculation unit 33 that calculates the
capacity of the storage battery 21 in a case where the UPS 11 is in use, the correlation15
determination unit 41 that determines the correlation between the resistance and the
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 the
capacity estimation unit 42 that estimates the capacity of the storage battery 21 in the
capacity estimation interval P1 between the (x-1)-th use and the x-th use of the UPS 1120
based on the correlation. Provided that x is an integer of 3 or more. The resistance
calculation unit 32 calculates the resistance a plurality of times in the pre-estimation
interval P2 before the (x-1)-th use of the UPS 11 and calculates the resistance in the
capacity estimation interval P1. The correlation determination unit 41 determines a
correlation based on the resistance calculated by the resistance calculation unit 32 in the25
24
pre-estimation interval P2 and the capacity calculated by the capacity calculation unit 33
in at least two uses of the UPS 11 among a first use to the (x-1)-th use. 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
interval P1.5
In addition, the degradation diagnosis system according to the present disclosure
includes the degradation diagnosis device and the UPS 11. The UPS 11 includes a storage
battery 21 and a BMU 22 that controls the storage battery 21.
[0065]
In addition, the degradation diagnosis method according to the present10
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 in a case where the UPS 11 is in use, a correlation determination step
of determining a correlation between the resistance and the capacity of the storage battery
21 based on the resistance calculated in the resistance calculation step and the capacity15
calculated in the capacity calculation step, and a capacity estimation step of estimating the
capacity of the storage battery 21 in a capacity estimation interval P1 between the (x-1)-th
use and the x-th use of the UPS 11 based on the correlation. Provided that x is an integer
of 3 or more. In the resistance calculation step, the resistance is calculated a plurality of
times in the pre-estimation interval P2 before the (x-1)-th use of the UPS 11 and the20
resistance is calculated in the capacity estimation interval P1. In the correlation
determination step, the correlation is determined based on the resistance calculated in the
resistance calculation step in the pre-estimation interval P2 and the capacity calculated in
the capacity calculation step in at least two uses of the UPS 11 among a first use to the (x-
1)-th use. In the capacity estimation step, the capacity of the storage battery 21 is25
25
estimated based on the correlation and the resistance calculated in the resistance calculation
step in the capacity estimation interval P1.
[0066]
The capacity of the storage battery 21 in the capacity estimation interval P1
between the (x-1)-th use and the x-th use of the UPS 11 can be estimated by calculating5
the resistance of the storage battery 21 in the capacity estimation interval P1. Therefore,
it is possible to perform the degradation diagnosis of the UPS 11 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 interval P2 and the capacity calculated in at least two uses of the UPS10
11 among a first use to the (x-1)-th use. Therefore, it is possible to perform the
degradation diagnosis of the UPS 11 without acquiring the data for the degradation
diagnosis in advance. Therefore, the maintainability and versatility can be improved.
[0067]
In addition, the degradation diagnosis device further includes a pulse generation15
device 15 including a pulse generation unit 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, the pulse
generation device 15 allowing the storage battery 21 to be discharged by switching the
switch 25. The resistance calculation unit 32 calculates the resistance of the storage
battery 21 based on the measurement results of the current and the voltage of the storage20
battery 21 in a case where the storage battery 21 is discharged by the pulse generation
device 15 in the capacity estimation interval P1. As a result, the degradation diagnosis
of the UPS 11 can be easily performed at any timing using the pulse generation device 15.
[0068]
In addition, the degradation diagnosis device further includes a capacity retention25
26
ratio calculation unit 43 that calculates the capacity retention ratio based on the capacity
of the storage battery 21 estimated by the capacity estimation unit 42. As a result, it is
possible to easily grasp the degradation state of the UPS 11.
[0069]
In addition, the degradation diagnosis device further includes the display unit 175
on which the estimation result of the capacity of the storage battery 21 by the capacity
estimation unit 42 is displayed. As a result, it is possible to easily grasp the degradation
diagnosis result of the UPS 11.
[0070]
Second embodiment.10
Next, a degradation diagnosis device, a degradation diagnosis system, and a
degradation diagnosis method according to a second embodiment will be described.
Since a basic configuration of the degradation diagnosis device according to the present
embodiment is the same as that of the first embodiment, descriptions will focus on
differences.15
[0071]
The decrease in the capacity of the storage battery 21 associated with the use of
the UPS 11 tends to be large in the initial stage. In the present embodiment, the
correlation determination unit 41 determines the correlation by excluding the resistance
and the capacitance in the initial stage among the resistance calculated by the resistance20
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 (that
is, the approximate curve Le) by excluding the resistance R1 and the capacity Q1 of the
storage battery 21 in the first use of the UPS 11 and the resistance R2 and the capacity Q2
of the storage battery 21 in the second use of the UPS 11.25
27
[0072]
As described above, in the present embodiment, the correlation determination unit
41 determines the correlation based on the resistance calculated by the resistance
calculation unit 32 in the pre-estimation interval P2 and the capacity calculated by the
capacity calculation unit 33 in at least two uses of the UPS 11 among a first use to the (x-5
1)-th use. Provided that n is an integer of 2 or more and x is an integer of 4 or more. As
a result, the diagnostic accuracy of the UPS 11 is improved.
It is noted that n is more preferably 3 or more and x is more preferably 5 or more.
[0073]
Third embodiment.10
Next, a degradation diagnosis device, a degradation diagnosis system, and a
degradation diagnosis method according to a third embodiment will be described. Since
the basic configuration of the degradation diagnosis device according to the present
embodiment is the same as that of the first embodiment, descriptions will focus on
differences.15
[0074]
In the present embodiment, the correlation determination unit 41 determines the
correlation by excluding the resistance and the capacitance having a large error among the
resistance calculated by the resistance calculation unit 32 and the capacity calculated by
the capacity calculation unit 33. Specifically, as shown in FIG. 9, the correlation20
determination unit 41 determines a resistance estimation curve Lr showing a transition of
the resistance of the storage battery 21 with the passage of time based on the resistance
calculated by the resistance calculation unit 32. The correlation determination unit 41
determines a capacity estimation curve Lc showing a transition of the resistance of the
storage battery 21 with the passage of time based on the capacity calculated by the capacity25
28
calculation unit 33. The correlation determination unit 41 determines the correlation by
excluding the resistance (in FIG. 9, the resistances er1 and er2) in which an error
(hereinafter, referred to as a resistance estimation error) with the resistance estimation
curve Lr is equal to or more than a first threshold value among the resistances calculated
by the resistance calculation unit 32, and the capacity (in FIG. 9, the capacity ec1) in which5
an error (hereinafter, referred to as a capacity estimation error) with the capacity estimation
curve Lc is equal to or more than a second threshold value among the capacity calculated
by the capacity calculation unit 33. The first threshold value and the second threshold
value are determined as follows, for example. That is, as shown in FIG. 10A, in a case
where the resistance estimation error is estimated to appear according to a normal10
distribution and the standard deviation with respect to the average of the resistance
estimation errors represents σ1, the first threshold value is, for example, 2σ1. The first
threshold value may be 3σ1. As shown in FIG. 10B, in a case where the capacity
estimation error is estimated to appear according to a normal distribution and a standard
deviation with respect to an average of the capacity estimation errors is σ2, the second15
threshold value is, for example, 2σ2. The second threshold value may be 3σ2.
[0075]
In the example of FIG. 11, the correlation determination unit 41 determines the
correlation (that is, the approximate curve Le) by excluding the resistance R1 and the
capacity Q1 of the storage battery 21 in the first use of the UPS 11 and the resistance R320
and the capacity Q3 of the storage battery 21 in the third use of the UPS 11, among the
resistance calculated by the resistance calculation unit 32 and the capacity calculated by
the capacity calculation unit 33.
[0076]
As described above, in the present embodiment, the correlation determination unit25
29
41 determines the resistance estimation curve Lr based on the resistance calculated by the
resistance calculation unit 32, and determines the capacity estimation curve Lc based on
the capacity calculated by the capacity calculation unit 33. The correlation determination
unit 41 determines the correlation by excluding the resistance in which the error with the
resistance estimation curve Lr is equal to or more than the first threshold value among the5
resistances calculated by the resistance calculation unit 32, and the capacity in which the
error with the capacity estimation curve Lc is equal to or more than the second threshold
value among the capacity calculated by the capacity calculation unit 33. As a result, the
diagnostic accuracy of the UPS 11 is improved.
[0077]10
Fourth embodiment.
Next, a degradation diagnosis device, a degradation diagnosis system, and a
degradation diagnosis method according to a fourth embodiment will be described. Since
a basic configuration of the degradation diagnosis device according to the present
embodiment is the same as that of the third embodiment, descriptions will focus on15
differences.
[0078]
In the present embodiment, the correlation determination unit 41 weights the
resistance calculated by the resistance calculation unit 32 and the capacitance calculated
by the capacity calculation unit 33 based on the capacitive resistance error and the capacity20
estimation error, and determines the correlation. Specifically, the error E is represented
by Expression (6) in a case where the weight is denoted by wi, the capacity (actual
measurement value) calculated by the capacity calculation unit 33 at the time of i-th use of
the UPS 11 is denoted by Qi, and Qx of Expression (4) is denoted by Q(ri).
25
30
[0079]
[0080]
That is, from Expression (4), the error E can be represented by Expression (7).
[0081]5
[0082]
It is noted that the weight wi is represented by Expression (8) using the variance
σ2 of the error E.
[0083]10
[0084]
The correlation determination unit 41 determines the coefficient A and the
constant B in Expression (4) such that the sum of products of the error E and the weight wi
is minimized. That is, the correlation determination unit 41 calculates the coefficients A15
and B such that Expression (6) is minimized, and weights the resistance calculated by the
resistance calculation unit 32 and the capacity calculated by the capacity calculation unit
33. The correlation determination unit 41 determines a correlation (that is, an
approximate curve Le) based on the weighted resistance and capacity. It is noted that the
weighting may be performed in the entire region of the pre-estimation interval P2 or may20
31
be performed only for a rear half portion of the pre-estimation interval P2. In a case
where the weighting is performed only on a rear half portion of the pre-estimation interval
P2, the accuracy of the degradation diagnosis can be improved in a case where the
resistance and the capacity of the storage battery 21 are significantly changed in the latter
half of the life of the UPS 11 in which the degradation of the UPS 11 progresses.5
[0085]
As described above, in the present embodiment, the correlation determination unit
41 determines the resistance estimation curve Lr based on the resistance calculated by the
resistance calculation unit 32, and determines the capacity estimation curve Lc based on
the capacity calculated by the capacity calculation unit 33. The correlation determination10
unit 41 weights the resistance calculated by the resistance calculation unit 32 and the
capacity calculated by the capacity calculation unit 33 based on an error between the
resistance calculated by the resistance calculation unit 32 and the resistance estimation
curve Lr and an error between the capacity calculated by the capacity calculation unit 33
and the capacity estimation curve Lc, and determines the correlation. As a result, the15
diagnostic accuracy of the UPS 11 is improved.
[0086]
Embodiment 5.
Next, a degradation diagnosis device, a degradation diagnosis system, and a
degradation diagnosis method according to a fifth embodiment will be described. Since20
a basic configuration of the degradation diagnosis device according to the present
embodiment is the same as that of the first embodiment, descriptions will focus on
differences.
[0087]
In the present embodiment, the capacity retention ratio calculation unit 4325
32
calculates the life of the UPS 11 based on the calculated capacity retention ratio.
FIG. 13 is a graph showing a transition of the capacity retention ratio of the storage
battery 21 with the horizontal axis representing time to the power of 0.5. As shown in
FIG. 13, in a case where the horizontal axis is time to the power of 0.5, the capacity
retention ratio of the storage battery 21 tends to decrease linearly. That is, in a case where5
the elapsed time from the initial state is denoted by t, the capacity retention ratio M can be
expressed by Expression (9). C and D are constants and are determined based on the
capacity retention ratio calculated by the capacity retention ratio calculation unit 43.
[0088]
10
[0089]
From Expression (9), the life tend of the UPS 11 is represented by Expression
(10).
[0090]
15
[0091]
For example, in a case where decrease in the capacity retention ratio to 60 (%) is
assumed as the life of the UPS 11, the life tend of the UPS 11 can be calculated by setting
M = 60 (%) in Expression (10).
[0092]20
The embodiments can be combined, and each embodiment can be modified or
omitted as appropriate.
33
[0093]
For example, in the above-described embodiment, a case of diagnosing the
degradation of the UPS 11 has been described, but the degradation diagnosis device, the
degradation diagnosis system, and the degradation diagnosis method of the present
disclosure can be applied to the diagnosis of the degradation of a storage battery system5
other than the UPS.
[0094]
In addition, the aforementioned control unit 36 includes a computer system inside.
A program for implementing functions of each configuration provided by the data center
1 described above may be recorded on a computer-readable recording medium, and by10
having the computer system read and execute the program recorded on this recording
medium, processing in the control unit 36 described above may be performed. In addition,
hardware other than the control unit 36 may perform the above-described processing.
[0095]
Here, the configuration "the computer system reads the program recorded in the15
recording medium and executes the program" includes installing the program in the
computer system. Here, the “computer system” mentioned here includes an operating
system (OS) and hardware such as a peripheral device.
[0096]
In addition, the “computer system” may include a plurality of computer devices20
connected via a network including a communication line such as the Internet, a WAN, a
LAN, and a dedicated line. In addition, the “computer-readable recording medium”
refers to a portable medium such as a flexible disk, a magneto-optical disk, a ROM, or a
CD-ROM, and a storage device such as a hard disk built in a computer system. In this
way, the recording medium on which the program is stored may be a non-transitory25
34
recording medium such as a CD-ROM.
[0097]
In addition, the recording medium also includes an internal or external recording
medium that is accessible by a distribution server for distributing the program. In
addition, a configuration may be adopted in which the program is divided into a plurality5
of programs and the plurality of programs are downloaded at different times and then
combined in each configuration provided in the data center 1, or the distribution server that
distributes each of the divided programs may be different. Furthermore, the “computer-
readable recording medium” also includes a medium that holds the program for a certain
period of time, such as a volatile memory (RAM) inside the computer system that serves10
as a server or a client in a case where the program is transmitted via a network. In addition,
the program may be a program for implementing some of the functions described above.
Furthermore, the program may be a so-called difference file (difference program) capable
of implementing the functions described above in combination with a program that has
already been recorded on the computer system.15
Reference Signs List
[0098]
1 Data center
2 Power system
11 UPS (storage battery system)20
12 Server storage (load)
15 Pulse generation device
16 Operation unit
17 Display unit
21 Storage battery25
35
22 BMU (storage battery control unit)
25 Switch
26 Pulse generation unit
31 Acquisition unit
32 Resistance calculation unit5
33 Capacity calculation unit
34 Storage unit
35 Degradation amount estimation unit
36 Control unit
41 Correlation determination unit10
42 Capacity estimation unit
43 Capacity retention ratio calculation unit
36
WE CLAIM:
[Claim 1] A degradation diagnosis device that diagnoses degradation of a storage battery
system, the degradation diagnosis device comprising:
a resistance calculation unit configured to calculate a resistance of a storage
battery of the storage battery system;5
a capacity calculation unit configured to calculate a capacity of the storage battery
during use of the storage battery system;
a correlation determination unit configured to determine a correlation between the
resistance and the capacity of the storage battery based on the resistance calculated by the
resistance calculation unit and the capacity calculated by the capacity calculation unit; and10
a capacity estimation unit configured to estimate the capacity of the storage
battery in a capacity estimation interval between an (x-1)-th use and an x-th use of the
storage battery system based on the correlation, where x is an integer of 3 or more,
wherein the resistance calculation unit calculates the resistance a plurality of times
in a pre-estimation interval up to the (x-1)-th use of the storage battery system and15
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 in at least two uses of the storage
battery system among a first use to the (x-1)-th use, and20
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.
[Claim 2] The degradation diagnosis device according to Claim 1, further comprising:
a pulse generation device including a pulse generation unit configured to25
37
generate a pulse signal and a switch that is switched between an on state and an off state
by the pulse signal, the pulse generation device allowing the storage battery to be
discharged by switching the switch,
wherein 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 in a5
case where the storage battery is discharged by the pulse generation device in the capacity
estimation interval.
[Claim 3] The degradation diagnosis device according to Claim 1 or 2, further
comprising:
a capacity retention ratio calculation unit configured to calculate a capacity10
retention ratio based on the capacity of the storage battery estimated by the capacity
estimation unit.
[Claim 4] The degradation diagnosis device according to any one of Claims 1 to 3,
further comprising:
a display unit on which an estimation result of the capacity of the storage battery15
by the capacity estimation unit is displayed.
[Claim 5] The degradation diagnosis device according to any one of Claims 1 to 4,
wherein 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 in at least two uses of the storage20
battery system among n-th use to the (x-1)-th use, where n is an integer of 2 or more and x
is an integer of 4 or more.
[Claim 6] The degradation diagnosis device according to any one of Claims 1 to 4,
wherein the correlation determination unit determines a resistance estimation
curve based on the resistance calculated by the resistance calculation unit, determines a25
38
capacity estimation curve based on the capacity calculated by the capacity calculation unit,
and determines the correlation by excluding a resistance in which an error with the
resistance estimation curve is equal to or more than a first threshold value among the
resistances calculated by the resistance calculation unit, and a capacity in which an error
with the capacity estimation curve is equal to or more than a second threshold value among5
the capacities calculated by the capacity calculation unit.
[Claim 7] The degradation diagnosis device according to any one of Claims 1 to 4,
wherein the correlation determination unit determines a resistance estimation
curve based on the resistance calculated by the resistance calculation unit, determines a
capacity estimation curve based on the capacity calculated by the capacity calculation unit,10
and weights the resistance calculated by the resistance calculation unit and the capacity
calculated by the capacity 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 capacity calculated by the capacity calculation unit and the capacity
estimation curve, to determine the correlation.15
[Claim 8] A degradation diagnosis system comprising:
the degradation diagnosis device according to any one of Claims 1 to 7; and
the storage battery system,
wherein the storage battery system includes a storage battery and a storage battery
control unit configured to control the storage battery.20
[Claim 9] A degradation diagnosis method for diagnosing degradation of a storage
battery system, the degradation diagnosis method 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 during25
39
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; and
a capacity estimation step of estimating the capacity of the storage battery in a5
capacity estimation interval between an (x-1)-th use and an x-th use of the storage battery
system based on the correlation, where x is an integer of 3 or more,
wherein in the resistance calculation step, the resistance is calculated a plurality
of times in a pre-estimation interval up to the (x-1)-th use of the storage battery system and
the resistance is calculated in the capacity estimation interval,10
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 in at least two uses of the storage
battery system among a first use to the (x-1)-th use, and
in the capacity estimation step, the capacity of the storage battery is estimated15
based on the correlation and the resistance calculated in the resistance calculation step in
the capacity estimation interval.