Technical Field

[0001]
The present invention relates to a battery deterioration detection device that detects deterioration of a storage battery, a battery deterioration detection method, and a program therefor.

Priority is claimed on Japanese Patent Application No. 2010-176565, filed August 5, 2010, the content of which is incorporated herein by reference.

Background Art

[0002]
In an electric system that carries out an electric control by using electric power that may be stored in a storage battery, it is preferable to have a configuration by which a deterioration state of a battery is detected early and a user is informed of the deterioration state. In this configuration, the occurrence of excessive cost due to early exchange of the storage battery or the occurrence of a failure of the electric system due to delay in the exchange of the storage battery may be prevented in advance. In addition, as a technology of detecting the battery deterioration, Patent Document 1 is disclosed.

Prior Art Documents Patent Documents

[0003] Patent Document 1: Japanese Patent Application, First Publication No. 2003-153454

Summary of Invention

Problem to be Solved by the Invention

[0004]
However, in the technology of the above-described Patent Document 1, a lithium ion secondary battery is charged with a constant current, and after the voltage value reaches a specified voltage value, the charging is subsequently transitioned to constant voltage charging in which the voltage is maintained. In addition, a deterioration degree of the battery is estimated by measuring current behavior of a current flowing to the battery at a time point at which a charging method is changed to the constant voltage charging and of a current flowing to the battery after passage of a predetermined time.

[0005]
However, in the technology of Patent Document 1, in a case where a load pattern of the storage battery may not be assumed, it is difficult to know when a situation of switching to the constant voltage charging after a voltage value reaches the specified voltage by performing the constant current charging occurs, and thus there is a problem in that the deterioration of the storage battery may not be detected at a desired time.

In addition, in a case where the deterioration degree is assumed from the current or voltage in an environment in which the temperature of the storage battery varies, it is necessary to exclude the influence exerted on the battery characteristics by the temperature.

[0006]
Therefore, an object of the invention is to provide a battery deterioration detection device, a battery deterioration detection method, and a program therefor, which are capable of solving the above-described problem.

Means for Solving the Problem

[0007]
To accomplish the above-described object, in an aspect of the invention, a battery deterioration detection device is provided, including: an internal resistance value-calculating unit that acquires a current value input to and output from a storage battery and a voltage value applied to the storage battery, and calculates a present internal resistance value of the storage battery by using a fluctuation range of the current value when the current value fluctuates by a given value or more and a fluctuation range of the voltage value at that time; and a battery deterioration information-processing unit that calculates a deterioration rate of the storage battery at a present temperature of the storage battery by dividing the current internal resistance value by an internal resistance initial value corresponding to the present temperature of the storage battery, and outputs the deterioration rate to a monitor device.

[0008]
In addition, in the above-described battery deterioration detection device of the invention, the internal resistance value-calculating unit may calculate the present internal resistance value in a case where a state, in which the fluctuation of the current flowing to and from the storage battery is a specified value or less, continues for a predetermined period before the current value fluctuates by the given value or more.

[0009]
In addition, the above-described battery deterioration detection device of the invention may further include an internal resistance initial value memory unit that stores the internal resistance initial value at each of different temperatures of the storage battery. The internal resistance value-calculating unit may calculate the internal resistance initial value corresponding to the temperature of the storage battery that is acquired, on the basis of the internal resistance initial value, which is stored in the internal resistance initial value memory unit, at each of the different temperatures.

[0010]
In addition, in the above-described battery deterioration detection device of the invention, the battery deterioration information-processing unit may calculate an average of a plurality of deterioration rates that are calculated, and outputs the average value of the deterioration rates to the monitor device.

[0011]
In addition, the above-described battery deterioration detection device of the invention may further include a remaining service-life-days-calculating unit that calculates the number of service life determination days that is determined as service life of the storage battery by using a square root law expressing a relationship between the number of operating days of the storage battery and the deterioration rate, and the deterioration rate at the internal resistance value of the storage battery in a state to be determined as the service life of the storage battery, and calculates the number of remaining service life days of the storage battery by subtracting the current number of operating days from the number of service life determination days.

[0012]
In addition, in another aspect of the invention, a battery deterioration detection method of a battery deterioration detection device is provided. The method includes: acquiring a current value input to and output from a storage battery and a voltage value applied to the storage battery, and calculating a present internal resistance value of the storage battery by using a fluctuation range of the current value when the current value fluctuates by a given value or more and a fluctuation range of the voltage value at that time; and calculating a deterioration rate of the storage battery at a present temperature of the storage battery by dividing the current internal resistance value by an internal resistance initial value corresponding to the present temperature of the storage battery, and outputting the deterioration rate to a monitor device.

[0013]
In addition, in still another aspect of the invention, a program is provided causing a computer of a battery deterioration detection device to execute: an internal resistance value-calculating process of acquiring a current value input to and output from a storage battery and a voltage value applied to the storage battery, and calculating a present internal resistance value of the storage batter}' by using a fluctuation range of the current value when the current value fluctuates by a given value or more and a fluctuation range of the voltage value at that time; and a battery deterioration information processing process of calculating a deterioration rate of the storage battery at a present temperature of the storage battery by dividing the current internal resistance value by an internal resistance initial value corresponding to the present temperature of the storage battery, and outputting the deterioration rate to a monitor device.

Advantageous Effects of the Invention

[0014]
In the invention, a current parameter value, a voltage parameter value, and a temperature parameter value of the storage battery are intermittently acquired, an internal resistance value at the time is calculated by using the parameter values to calculate a deterioration rate of the storage battery, and it is determined whether or not the deterioration rate of the storage battery becomes equal to or greater than a limit deterioration rate by using the deterioration rate with good accuracy. Therefore, it is possible to detect a deterioration state of the battery regardless of a load pattern of the storage battery.

Brief Description of the Drawings

[0015]
FIG 1 is a block diagram illustrating a configuration of a battery deterioration detection device.

FIG 2 is a schematic configuration diagram of a BMS and a storage battery.

FIG 3 is a functional block diagram of a controller.

FIG 4 is a diagram illustrating a relationship between an internal resistance value and a temperature of the storage battery.

FIG 5 is a diagram illustrating an equivalent circuit of a secondary battery.

FIG 6 is a graph illustrating a relationship between the number of operating days and a deterioration rate of the storage battery.

Mode for Carrying Out the Invention

[0016]
Hereinafter, a battery deterioration detection device in an embodiment of the invention will be described with reference to the attached drawings.
FIG 1 shows a block diagram illustrating a configuration of a battery deterioration detection device in the same embodiment.

In this embodiment, for example, a battery deterioration detection device 1 is provided to an RTG (Rubber Tired Gantry crane) which operate based on electric power stored in a storage battery, and vehicles of new transportation systems such as an APM (Automated People Mover) or an LRT (Light Rail Transit) or the like.
In addition, the battery deterioration detection device 1 is provided with a storage battery 10, a BMS (Battery Management System) 20, a controller (Programmable Logic Controller) 30, a display device 40, and an electric power load 50.

[0017]
Here, in addition to the RTG, the APM, and the LRT, the battery deterioration detection device 1 of the invention may be provided, for example, to an electric vehicle, an industrial vehicle such as a fork lift, an electric train, and a moving body such as an airplane and a ship whose propeller or screw is connected to an electric motor as the electric power load 50. Furthermore, the battery deterioration detection device 1 may be provided, for example, in stationary systems such as a power storage system for a house, and a grid stabilization power storage system that is combined with a windmill or power generation with natural energy such as solar light.

[0018]
The storage battery 10 supplies electric power to the electric power load 50 of an electric system provided with the battery deterioration detection device 1. In this embodiment, the storage batter)' 10 is made up by a secondary battery 11. In addition, the storage battery 10 may be configured in such a manner that a plurality of secondary batteries 11 are connected in series. In addition, the storage battery 10 may be made up by connecting a plurality of secondary batteries 11 in parallel with each other. Each of the secondary batteries 11 making up the storage battery 10 is provided with various kinds of sensors that measure the temperature, voltage, current, and the like, and measurement information, which is measured by these sensors and output therefrom, is input to the BMS 20 to be described later in detail. In addition, in a case where the storage battery 10 is made up by the plurality of secondary batteries 11, the various kinds of sensors are provided thereto, respectively.

[0019]
The controller 30 receives the measurement information, which is transmitted from the BMS 20, of the storage battery 10, and the like, and controls the display device 40 to appropriately display related information (a deterioration rate, the number of remaining service life days, and the like of the storage battery), which is calculated on the basis of the measurement information, of the storage battery 10. In addition, in a case where the related information is determined as an abnormal value, the controller 30 turns on an abnormality lamp 401 that is embedded in the display device 40 (a display may be an optical display, and thus a display indicating abnormality may be displayed on a monitor screen to be described later), and gives the alarm by activating an acoustic device such as a buzzer that is embedded in the display device 40 so as to attract a user's attention by stimulating the sense of sight and the sense of hearing by using light and sound.

[0020]
The display device 40 is, for example, a monitor such as a liquid crystal panel provided with the acoustic device, and performs displaying of the related information of the secondary battery 11 making up the storage battery 10 on the basis of control by the controller 30.

For example, the electric power load 50 is a power converter such as an electric motor and an inverter that are connected to wheels of a vehicle. The electric power load 50 may be an electric motor that drives a wiper or the like.

[0021]
Next, the BMS 20 will be briefly described and then an operation thereof will be described in detail.

As shown in FIG 1, the BMS 20 of the battery deterioration detection device 1 includes a CMU (Cell Monitor Unit) 21 and a BMU (Battery Management Unit) 23.

Here, the CMU 21 is provided with an ADC (Analog Digital Converter) (not shown), receives a plurality of pieces of the measurement information that is sensed by and output from the various kinds of sensors as analog signals, respectively, converts the analog signals to digital signals corresponding thereto by the ADC, respectively, and then outputs the converted signals to the BMU 23 as a plurality of parameters for calculating the related information. In this embodiment, as shown in FIG 1, the CMU 21 is connected to the secondary battery 11 by a signal line.

[0022]
In addition, the BMU 23 outputs the parameters, which are input from the CMU 21, of the storage battery 10 to the controller 30.
In addition, here, one piece of the CMU 21 is illustrated, but it is not limited to this aspect. For example, in a case where the storage battery 10 is made up by a plurality of secondary batteries 11, the CMU 21 may be provided in plural numbers. In this case, plural pieces of the secondary batteries 11 may be connected to each CMU 21, respectively, or the CMU 21 may be provided in one-to-one relationship with respect to the plurality of secondary batteries 11. That is, any number of CMUs 21 may be provided as long as a plurality of parameters, which are necessary for performing a deterioration rate-calculating process or a remaining service-life-days-calculating process by the BMU 23, may be acquired from the CMU 21. In a case where the BMU 23 is configured to include the CMU 21, the BMS 20 may be made up by only the BMU 23.
rrvmi

FIG 2 shows a schematic configuration diagram of the BMS and the storage battery.

Next, an internal configuration and an operation of the BMS 20 will be described in detail with reference to FIG 2.

As shown in FIG 2, a voltmeter 3 is provided to the secondary battery 11 making up the storage battery 10. Specifically, the voltmeter 3 is connected between a positive electrode terminal and a negative electrode terminal of the secondary battery 11. In addition, the CMU 21 is provided with a parameter value-detecting unit 211, and the parameter value-detecting unit 211 acquires a voltage value, which is measurement information measured by and output from the voltmeter 3, as an analog signal (the analog signal is input to the parameter value-detecting unit 211).

[0024]
In addition, an ammeter 2 is connected between the storage battery 10 and the electric power load 50 to measure a current flowing to the electric power load 50. In addition, the parameter value-detecting unit 211 acquires a current value, which is measurement information measured by and output from the ammeter 2, as an analog signal (the analog signal is input to the parameter value-detecting unit 211).
In addition, a thermometer 4 is attached to a casing of the secondary battery 11 making up the storage battery 10.

In addition, the parameter value-detecting unit 211 acquires a temperature value, which is measurement information measured by and output from the thermometer 4, as an analog signal (the analog signal is input to the parameter value-detecting unit 211).

[0025]
In addition, the parameter value-detecting unit 211 includes the ADC that embedded therein, and thus converts the analog signals that are the current value, the voltage value, and the temperature value acquired from the ammeter 2, the voltmeter 3, and the thermometer 4 to digital signals, and outputs the converted digital signals to the BMU 23 as corresponding parameter values, respectively. In addition, the BMU 23 outputs the current value, the voltage value, and the temperature value that are acquired to the controller 30. The controller 30 performs a deterioration rate-calculating process or a remaining service-life-days-calculating process by using the current value, the voltage value, and the temperature value that are acquired.

[0026]
FIG 3 shows a functional block diagram of the controller.
As shown in FIG 3, the controller 30 is provided with a parameter-acquiring unit 31, a memory unit 32 (an internal resistance initial value memory unit), a battery deterioration information-processing unit 33 that performs the deterioration rate-calculating process, a remaining service-life-days-calculating unit 34 that performs the remaining service-life-days-calculating process, and an internal resistance value-calculating unit 35 that calculates an internal resistance value of the storage battery 10.

First, the parameter-acquiring unit 31 acquires a parameter value, which corresponds to an inter-terminal voltage value of the secondary battery 11 (a voltage value between a positive electrode terminal and a negative electrode terminal in the secondary battery 11) provided inside the storage battery 10 (a parameter of the voltage of the secondary battery 11 is referred to as a "an inter-terminal voltage parameter V", and the value thereof is referred to as a "inter-terminal voltage parameter value"), from the BMS 20.

In addition, the parameter-acquiring unit 31 acquires a parameter value, which corresponds to a current value that is measured by the ammeter 2 and flows to and from the storage battery 10 (the parameter is referred to as a "current parameter I" and the value thereof is referred to as a "current parameter value"), from the BMS 20.

In addition, the parameter-acquiring unit 31 acquires a parameter value of a temperature, which is measured by the thermometer 4, of the casing of the secondary battery 11 making up the storage battery 10 (the parameter is referred to as a "temperature parameter T" and the value thereof is referred to as a "temperature parameter value") from the BMS 20.

In addition, the parameter-acquiring unit 31 outputs the current parameter value, the voltage parameter value, and the temperature parameter value to the internal resistance value-calculating unit 35, and records these parameter values in the memory unit 32.

[0027]
Here, the internal resistance value-calculating unit 35 stores the current parameter value, the voltage parameter value, and the temperature parameter value, which are acquired from the parameter-acquiring unit 31 prior to an immediately preceding time, in a memory or the like. In addition, the internal resistance value-calculating unit 35 compares a current parameter value that is acquired at the immediately preceding time and a current parameter value that is currently acquired from the parameter-acquiring unit 31, and determines whether or not the current parameter values fluctuate by a given value or more.

In addition, in a case where it is determined that the difference between the immediately preceding current parameter value and the present current parameter value fluctuate by a given value or more, the internal resistance value-calculating unit 35 calculates an internal resistance value of the storage battery 10. In addition, in a case where the difference between the immediately preceding current parameter value and the present current parameter value do not fluctuate by a given value or more, noise may be mixed in the internal resistance of the storage battery 10 at the time of calculating it. Therefore, in a case where the difference between the immediately preceding current parameter value and the present current parameter value do not fluctuate by a given value or more, the internal resistance value-calculating unit 35 stops the calculation of the internal resistance value of the storage battery 10. In addition, in the internal resistance value-calculating process, the internal resistance value-calculating unit 35 calculates the difference between the immediately preceding current parameter value and the present current parameter value to obtain a fluctuation value AI of the current parameter value, and calculates the difference between an immediately preceding voltage parameter value and the present voltage parameter value to obtain a fluctuation value AV of the voltage parameter value. In addition, the internal resistance value-calculating unit 35 determines whether or not the calculated AI is a given value or more. Where the calculated AI is the given value or more, the internal resistance value-calculating unit 35 calculates an internal resistance value R of the storage battery 10 by using the fluctuation value AI of the current parameter value and the fluctuation value AV of the voltage parameter value when the current parameter value fluctuates, that is, the expression R = AVs-AI.

[0028]
FIG 4 shows a diagram illustrating a relationship between the internal resistance value and a temperature of the storage battery.
The controller 30 stores an initial value Rini (hereinafter, referred to as an internal resistance initial value Rini) of the internal resistance value corresponding to each of a plurality of temperatures of the storage battery 10 in the memory unit 32 in advance. Here, as shown in FIG 4, in regard to the internal resistance value of the storage battery 10, it is known that as the temperature rises, the internal resistance value decreases in an inversely proportional manner. In addition, as shown in FIG 4, in regard to the internal resistance value of the storage battery 10, it is known that as the storage battery 10 deteriorates, a characteristic of the resistance thereof (a relationship between the internal resistance value and the temperature) varies in the direction of the arrow. That is, it is known that where the storage battery 10 deteriorates, even at the same temperature, the internal resistance value further increases compared to before deterioration.

[0029]
In addition, a deterioration rate y of the storage battery 10 (the secondary battery 11) is a proportion of a present internal resistance value R with respect to the internal resistance initial value P.ini, and may be calculated by the deterioration rate calculation expression y=R-Rini. However, as shown in FIG 4, the internal resistance initial value Rini also varies in response to the temperature of the storage battery 10. Therefore, it is possible to calculate the deterioration rate y with good accuracy by using the internal resistance initial value Rini of the storage battery 10 at the same temperature as that of the storage battery 10 at the time the present internal resistance value is calculated. In addition, immediately before it is determined that the difference between the immediately preceding current parameter value and the present current parameter value fluctuate by a given value or more, the internal resistance value-calculating unit 35 calculates the internal resistance initial value Rini of the storage battery 10 at the same temperature as that indicated by a newly acquired temperature parameter value.

[0030]
At this time, internal resistance value-calculating unit 35 reads out the internal resistance initial value Rini corresponding to each of the plurality of temperatures around a temperature indicated by a newly acquired temperature parameter value from the memory unit 32, and calculates the internal resistance initial value Rini corresponding to the newly acquired temperature parameter by interpolation calculation. In addition, the internal resistance value-calculating unit 35 outputs the calculated internal resistance value R and internal resistance initial value Rini to the battery deterioration information-processing unit 33. In addition, the battery deterioration information-processing unit 33 calculates a present deterioration rate y of the storage battery 10 by the above-described deterioration rate value-calculating expression.

In addition, the battery deterioration information-processing unit 33 acquires the internal resistance value R and the internal resistance initial value Rini, which are calculated by the internal resistance value-calculating unit 35, from the internal resistance value-calculating unit 35 for each predetermined period, calculates the deterioration rate y, and outputs this deterioration rate y to the display device 40. At this time, in a case where a plurality of deterioration rates y are calculated within the predetermined period, the battery deterioration information-processing unit 33 outputs an average value of the plurality of deterioration rates y to the display device 40. The display device 40 displays the deterioration rates y that are input and acquired from the controller 30 on a monitor or the like.

[0031]
In addition, in a case where the calculated deterioration rates y or the average value thereof is equal to or greater than a limit deterioration rate ylimit (a service life determination value of the deterioration rate) that is determined as the service life of the battery, the battery deterioration information-processing unit 33 determines that the storage battery 10 reaches the service life thereof, and outputs alarm information to the display device 40. In this case, the display device 40 informs the user of an abnormality of the storage battery by turning on the abnormality lamp 401, or the like. In addition, when it is determined whether or not the calculated deterioration rates y or the average value thereof is equal to or greater than the limit deterioration rate ylimit, the battery deterioration information-processing unit 33 reads out the limit deterioration rate ylimit from the memory unit 32 and compares the limit deterioration rate ylimit with the calculated deterioration rates y or the average value thereof.

[0032]
In the above-described process, the current parameter value, the voltage parameter value, and the temperature parameter value of the storage battery 10 are intermittently acquired, and the internal resistance value R at the time is calculated by using the parameter values. In addition, it is determined whether or not the deterioration rate becomes equal to or greater than the limit deterioration rate ylimit by using the deterioration rate y. Therefore, it is possible to detect a deterioration state of the battery regardless of a load pattern of the storage battery 10.

In addition, the deterioration rate y is calculated with good accuracy by using the internal resistance initial value Rini of the storage battery 10 at the same temperature as that of the storage battery 10 at the time the present internal resistance value is calculated, and it is determined whether or not the deterioration rate y becomes equal to or greater than the limit deterioration rate ylimit. Therefore, since the deterioration state is detected in a state in which influence exerted on the internal resistance of the storage battery due to the temperature is excluded, the deterioration state may be determined with good accuracy.

In addition, since it is possible to display the deterioration state with good accuracy of the storage battery 10 by the display device 40, the occurrence of excessive cost due to early exchange of the storage battery 10 or a problem due to delay in the exchange thereof may be prevented in advance at a relatively appropriate timing.

[0033]
Here, details of the limit deterioration rate ylimit will be described.
The limit deterioration rate ylimit represents the proportion of an internal resistance value Rltmit in a state to be determined as the service life of the storage battery 10 with respect to the internal resistance initial value Rini of the storage battery 10 and may be calculated by the expression ylimit = RlimiHRini. Here, the internal resistance value Rlimit in a state to be determined as the service life of the storage battery 10 represents an internal resistance value when either a voltage value of V_VOCmax+(IcmaxxRlimit) or a voltage value of V_VOCmin-(IdmaxxRlimit) deviates from a permitted voltage value of the storage battery 10. The V_VOCmax+(IcmaxxRlimit) represents a voltage value that is applied to the storage battery 10 during operation in a case where an open circuit voltage at the maximum SOC (state of charge; charging rate) of the storage battery 10, which is assumed during operation, is set to VVOCmax, and the maximum current design value flowing to the storage battery 10 during charging is set to Icmax. The V_VOCmin-(IdmaxxRlimit) represents a voltage value that is applied to the storage battery 10 during operation in a case where an open circuit voltage at the minimum SOC of the storage battery 10, which is assumed during operation, is set to VVOCmin, and the maximum current design value flowing to the storage battery 10 during discharging is set to Idmax.

[0034]
In addition, the above-described maximum current design value Icmax flowing to the storage battery 10 during charging represents a value that is calculated by the expression Icmax= | PcmaxVVmin | where the maximum charging electric power design value that is a characteristic of the storage battery 10 is set to Pcmax, and the minimum battery voltage design value is set to Vmin. In addition, the above-described maximum current design value Idmax flowing to the storage battery 10 during discharging represents a value that is calculated by the expression Idmax= | Pcmin-nVmin | where the minimum charging design value of the storage battery 10 is set to Pcmin, and the minimum battery voltage design value is set to Vmin.

[0035]
In addition to the above-described process, the battery deterioration information-processing unit 33 also determines that the storage battery 10 reaches the service life thereof and outputs alarm information to the display device 40 when comparing the voltage parameter value that is input and acquired from the parameter-acquiring unit 31 with the permitted voltage value of the storage battery 10 which is recorded in the memory unit 32, the voltage parameter value exceeds the permitted voltage value. Also at this time, the display device 40 informs a user of an abnormality of the storage battery by turning on the abnormality lamp 401, or the like.

[0036]
In addition, in the above-described process, the battery deterioration information-processing unit 33 compares a current parameter value that is acquired at an immediately preceding time and a current parameter value that is acquired at a present time from the parameter-acquiring unit 31, and determines whether or not the parameter values fluctuate by a given value or more. In a case where it is determined that the current parameter values fluctuate by the given value or more, the battery deterioration information-processing unit 33 calculates the internal resistance value of the storage battery 10. However, the battery deterioration information-processing unit 33 may calculate the internal resistance value of the storage battery 10 only in a case where a state, in which the fluctuation of the current parameter value flowing to and from the secondary battery 11 making up the storage battery 10 becomes a specified value or less, continues for a given time t or longer immediately before it is determined that the current parameter value fluctuates by the given value or more.

[0037]
FIG 5 shows an equivalent circuit diagram of the secondary battery.
That is, as shown in this drawing, the secondary battery 11 making up the storage battery 10 includes a condenser component, and thus irregularity of the internal resistance value, which is detected as AV/AI, becomes large immediately after variation of the current due to the influence of a voltage Vc of the condenser component. Therefore, so as to make this gap small, it is preferable to calculate the internal resistance value of the secondary battery 11 making up the storage battery 10 only in a case where a state in which the fluctuation of the current parameter value flowing to and from the secondary battery 11 making up the storage battery 10 being a specified value or less continues for a given time t or longer. In addition, the value of the given time t may be larger than a time constant of a CR circuit shown in FIG 5.

Due to this, detection accuracy of the internal resistance value R or the deterioration rate y is further improved, and thus the determination accuracy of the deterioration state of the storage battery 10 may be improved.

[0038]
FIG 6 shows a graph illustrating a relationship between the number of operating days and the deterioration rate of the storage battery.

As shown in this drawing, as the number of operating days of the storage battery 10 increases, the deterioration rate y of the storage battery 10 approaches the limit deterioration rate ylimit (a service life determination value). More specifically, it is known that the relationship between the number of operating days and the deterioration rate is based on the square root law in which an increase in the internal resistance of the storage battery 10 is proportional to a square root of the number of charging and discharging cycles or the number of operating days, and the relationship is expressed by the square root expression y=l+WN. In addition, N represents the number of operating days, k represents a deterioration acceleration coefficient, and y is 1.0 at the time of operation initiation.

Here, the deterioration acceleration coefficient k may be calculated from the square root law expression, the number of present operating days N, and the present deterioration rate y. In addition, the number of service life determination days Nlimit when the deterioration rate becomes ylimit may be calculated by using the deterioration acceleration coefficient k and the limit deterioration rate ylimit. The remaining service-life-days-calculating unit 34 of the controller 30 calculates the number of service life determination days Nlimit at any determined timing and records it in the memory unit 32. In addition, the remaining service-life-days-calculating unit 34 frequently records, for example, the number of days passed from operation initiation of the storage battery 10 in the memory unit 32, and calculates the number of remaining service life days by subtracting the number of days passed, which is recorded in the memory unit 32, from the number of service life determination days Nlimit that is calculated. In addition, the remaining service-life-days-calculating unit 34 outputs the number of remaining service life determination days, which is calculated, to the display device 40. Due to this, the display device 40 displays the number of remaining service life days on the monitor.

In this process, it is possible to inform a user of the number of service life days that is predicted, and thus it is possible to easily prevent occurrence of excessive cost due to early exchange of the storage battery or a problem due to delay in the exchange may be prevented in advance.

In addition, in the above-described process, the number of service life determination days Nlimit is calculated at a predetermined timing. However, a number of service life determination days Nlimit may be obtained at a predetermined interval, and the number of remaining service life days shown in the latest storage battery 10 state may be calculated by using the latest number of sendee life determination days Nlimit.

[0039]
In addition, in a case where the storage battery 10 is made up by a plurality of secondary batteries 11, the calculation of the deterioration rate, the determination whether or not it reaches the service life, and the calculation of the number of remaining service life days may be performed for each of the secondary batteries 11. In addition, in a case where it is necessary to exchange the plurality of secondary batteries 11 making up the storage battery 10 at a time, the determination whether or not it reaches the service life and the calculation of the number of remaining service life days may be performed for the storage battery 10 unit by using an internal resistance value (a sum of internal resistance values of the respective secondary batteries 11) or a deterioration rate (an average value of deterioration rates of the respective secondary batteries), which is calculated by setting the plurality of secondary batteries 11 as one unit, of the storage battery 10.

[0040]
The controller 30 and the display device 40 of the above-described battery deterioration detection device 1 are provided with a computer system therein. In addition, in regard to each of the above-described processing processes, the processing is performed by causing a computer to read out a program stored in a computer-readable recording medium in a program type and to execute the processing. Here, the computer-readable recording medium represents a magnetic disk, a magneto-optical disc, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like. In addition, the computer program may be transmitted to the computer via a communication line and the computer receiving the program may executes the program.

[0041]
In addition, the program may be a program that realizes a part of the above-described functions.

Furthermore, the program may be a program which may realize the above-described functions by a combination with a program that is recorded already in the computer system, that is, a so-called differential file (a differential program).

Industrial Applicability

[0042]
In the invention, a current parameter value, a voltage parameter value, and a temperature parameter value of the storage battery are intermittently acquired, an internal resistance value at the time is calculated by using the parameter values to calculate a deterioration rate of the storage battery, and it is determined whether or not the deterioration rate of the storage battery becomes equal to or greater than a limit deterioration rate by using the deterioration rate with good accuracy. Therefore, it is possible to detect a deterioration state of the battery regardless of a load pattern of the storage battery.

Description of Reference Numerals

[0043]
1: Battery deterioration detection device 2: Ammeter 3: Voltmeter 4: Thermometer 10: Storage battery 11: Secondary battery 20: BMS 21:CMU 23: BMU 30: Controller
31: Parameter-acquiring unit 32: Memory unit
33: Battery deterioration information processing unit 34: Remaining service-life-days-calculating unit
35: Internal resistance value-calculating unit 40: Display device 50: Electric power load

I/We Claim:

1. A battery deterioration detection device, comprising:

an internal resistance value-calculating unit that acquires a current value input to and output from a storage battery and a voltage value applied to the storage battery, and calculates a present internal resistance value of the storage battery by using a fluctuation range of the current value when the current value fluctuates by a given value or more and a fluctuation range of the voltage value at that time; and
a battery deterioration information-processing unit that calculates a deterioration rate of the storage battery at a present temperature of the storage battery by dividing the current internal resistance value by an internal resistance initial value corresponding to the present temperature of the storage battery, and outputs the deterioration rate to a monitor device.

2. The battery deterioration detection device according to Claim 1, wherein the internal resistance value-calculating unit calculates the present internal resistance value in a case where a state, in which the fluctuation of the current flowing to and from the storage battery is a specified value or less, continues for a predetermined period before the current value fluctuates by the given value or more.

3. The battery deterioration detection device according to Claim 1 or 2, further comprising:

an internal resistance initial value memory unit that stores the internal resistance initial value at each of different temperatures of the storage battery, wherein the internal resistance value-calculating unit calculates the internal resistance initial value corresponding to the temperature of the storage battery that is acquired, on the basis of the internal resistance initial value, which is stored in the internal resistance initial value memory unit, at each of the different temperatures.

4. The battery deterioration detection device according to any one of Claims 1
to 3, wherein the battery deterioration information-processing unit calculates an average of a plurality of deterioration rates that are calculated, and outputs the average value of the deterioration rates to the monitor device.

5. The battery deterioration detection device according to any one of Claims 1 to 4, further comprising:

a remaining service-life-days-calculating unit that calculates the number of service life determination days that is determined as service life of the storage battery by using a square root law expressing a relationship between the number of operating days of the storage battery and the deterioration rate, and the deterioration rate at the internal resistance value of the storage battery in a state to be determined as the service life of the storage battery, and calculates the number of remaining service life days of the storage battery by subtracting the current number of operating days from the number of service life determination days.

6. A battery deterioration detection method of a battery deterioration detection device, the method comprising:

acquiring a current value input to and output from a storage battery and a voltage value applied to the storage battery, and calculating a present internal resistance value of the storage battery by using a fluctuation range of the current value when the current value fluctuates by a given value or more and a fluctuation range of the voltage value at that time; and

calculating a deterioration rate of the storage battery at a present temperature of the storage battery by dividing the current internal resistance value by an internal resistance initial value corresponding to the present temperature of the storage battery, and outputting the deterioration rate to a monitor device.

7. A program causing a computer of a battery deterioration detection device to execute:

an internal resistance value-calculating process of acquiring a current value input to and output from a storage battery and a voltage value applied to the storage battery, and calculating a present internal resistance value of the storage battery by using a fluctuation range of the current value when the current value fluctuates by a given value or more and a fluctuation range of the voltage value at that time; and
a battery deterioration information processing process of calculating a deterioration rate of the storage battery at a present temperature of the storage battery by dividing the current internal resistance value by an internal resistance initial value corresponding to the present temperature of the storage battery, and outputting the deterioration rate to a monitor device.