WO2021090632A1

WO2021090632A1 - Battery diagnosis device, forklift, charger, battery diagnosis method, and program

Info

Publication number: WO2021090632A1
Application number: PCT/JP2020/038108
Authority: WO
Inventors: 小林　克明; 敏康木藪; 田島　英彦; 小城　育昌
Original assignee: 三菱重工業株式会社
Priority date: 2019-11-06
Filing date: 2020-10-08
Publication date: 2021-05-14
Also published as: JP2021076421A

Abstract

This battery diagnosis device is provided with: a first impedance acquisition unit that acquires the impedance of a battery to be diagnosed at a first frequency; a second impedance acquisition unit that acquires the impedance of the battery at a second frequency; and a performance diagnosis unit that diagnoses the performance of the battery on the basis of a difference value between the impedance at the first frequency and the impedance at the second frequency.

Description

Battery diagnostic equipment, forklifts, chargers, battery diagnostic methods and programs

This disclosure relates to battery diagnostic devices, forklifts, chargers, battery diagnostic methods and programs. The present application claims priority based on Japanese Patent Application No. 2019-201607 filed in Japan on November 6, 2019, the contents of which are incorporated herein by reference.

For devices that use batteries (lead batteries, etc.) such as forklifts, the battery performance determines the performance (driving time, etc.) of the device. Since the capacity of a battery (lead battery) decreases due to deterioration as the battery is operated, it is important to diagnose the deterioration status of the battery.
Generally, as a performance evaluation of a battery (lead battery), the deterioration status can be evaluated by measuring the battery capacity of the battery, but when measuring the battery capacity by actual charging / discharging, it takes a long time of about 5 to 10 hours. ..
Therefore, in the maintenance of equipment, a method of quickly diagnosing the performance of the battery by evaluating the internal resistance of the battery is adopted. For example, there are the following commercially available tools.
(1) Measuring AC impedance at a relatively high frequency (1 kHz) (2) Measuring AC impedance at a relatively low frequency (25 Hz) (3) Measuring internal resistance by short-time discharge of DC current

Patent Document 1 discloses that the internal resistance of a battery is estimated by using an equivalent circuit composed of a parallel circuit of a charge transfer resistance value and an electric double layer capacitance value and a series circuit of an electrolyte resistance value. ..

Japanese Patent No. 4477185

Since all of the above (1) to (3) use the measured values of a specific single frequency (or direct current only), the conduction / contact resistance (ohmic resistance component; measured in the high frequency range of 100 Hz or higher) of the terminal portion is measured. It is affected by the variation of). Although a certain correlation is observed between the battery capacity and the impedance, the conduction / contact resistance of the terminal portion does not necessarily have a correlation with the capacity, and thus there is a problem in the accuracy of diagnosis in this respect.

An object of the present disclosure is to provide a battery diagnostic device, a forklift, a charger, a battery diagnostic method and a program capable of diagnosing battery performance with high accuracy.

According to one aspect of the present disclosure, the battery diagnostic apparatus has a first impedance acquisition unit that acquires impedance at the first frequency of the battery to be diagnosed, and a second impedance acquisition unit that acquires impedance at the second frequency of the battery. It includes an impedance acquisition unit and a battery capacity calculation unit that calculates the battery capacity or the degree of deterioration of the battery based on the difference value between the impedance at the first frequency and the impedance at the second frequency.

According to each of the above aspects, the battery performance can be diagnosed with high accuracy.

It is a figure which shows the outline of the battery diagnostic apparatus which concerns on 1st Embodiment. It is a figure which shows the structure of the battery diagnostic apparatus which concerns on 1st Embodiment. It is a figure which shows the functional structure of the CPU which concerns on 1st Embodiment. It is a figure which shows the equivalent circuit of the battery which concerns on 1st Embodiment. It is a figure which shows the impedance frequency characteristic of the battery which concerns on 1st Embodiment. It is a figure which shows the example of the relationship between the impedance measurement value at each frequency, and the battery capacity. It is a figure which shows the difference of impedance at each frequency shown in FIG. It is a figure which shows the difference of impedance at each frequency shown in FIG. It is a figure which shows the processing flow executed by the CPU which concerns on 1st Embodiment. It is a figure which shows the example of the battery capacity table which concerns on 1st Embodiment. It is a figure which shows the structure of the battery diagnostic apparatus which concerns on 2nd Embodiment. It is a figure which shows the functional structure of the CPU which concerns on 2nd Embodiment. It is a figure which shows the example of the temperature compensation table which concerns on 2nd Embodiment. It is a figure which shows the outline of the battery diagnostic apparatus which concerns on other embodiment.

<First Embodiment>
Hereinafter, the battery diagnostic device according to the first embodiment and the forklift provided with the battery diagnostic device will be described with reference to FIGS. 1 to 9.

(Overview of battery diagnostic device)
FIG. 1 is a diagram showing an outline of the battery diagnostic apparatus according to the first embodiment.
The forklift F shown in FIG. 1 is a forklift equipped with a battery B, which is a lead storage battery, and uses the battery B as a power source. The forklift F according to the present embodiment includes a battery diagnostic device 1 for diagnosing the performance of the battery B. As will be described later, the battery diagnostic device 1 transmits the diagnosis result to the server device S installed at a remote location, for example, by wireless communication. The server device S accumulates the diagnosis results of the battery performance of the plurality of forklifts F (battery diagnostic device 1). According to this server device S, the battery performance of the plurality of forklifts F is centrally managed.
In the present embodiment, "diagnosing the performance of the battery" will be described as measuring the battery capacity of the battery. However, in other embodiments, the present invention is not limited to this, and for example, the ratio (deterioration degree) of the current battery capacity to the initial battery capacity may be measured.

(Battery diagnostic device configuration)
FIG. 2 is a diagram showing a configuration of a battery diagnostic device according to the first embodiment.
As shown in FIG. 2, the battery diagnostic device 1 includes a CPU 10, a power supply circuit 11,

oscillation circuits

12A and 12B, a selector 13, an impedance measurement circuit 14, a memory 15, and a transceiver 16.

The CPU 10 is a processor that controls the operation of the entire battery diagnostic device 1. The function of the CPU 10 will be described later.
The power supply circuit 11 is a circuit that receives power supply from the power supply (battery B) and supplies power (power supply voltage) to each configuration of the battery diagnostic device 1. In FIG. 13, the connection line related to the power supply is shown by a thick line.
The

oscillation circuits

12A and 12B are circuits capable of outputting signals (AC voltage) having a defined frequency, respectively. In the present embodiment, the oscillation circuit 12A is a transmission circuit that outputs a 0.1 Hz signal, and the oscillation circuit 12B is a transmission circuit that outputs a 10 Hz signal.
The selector 13 is a circuit that selects and outputs either the output signal of the oscillation circuit 12A or the output signal of the oscillation circuit 12B based on the control signal from the CPU 10.
The impedance measurement circuit 14 is a circuit that detects the voltage between terminals of an object (battery B) generated based on the output signal of the

oscillation circuit

12A or 12B. The impedance [Ω] of the object is measured by comparing the output signal of the

transmission circuit

12A or 12B and the voltage between terminals detected by the impedance measurement circuit 14 in amplitude and phase.
The memory 15 is a storage area required for the operation of the CPU 10. In the present embodiment, the battery capacity table T1 prepared in advance is recorded in the memory 15. The battery capacity table T1 will be described later.
The transceiver 16 is a circuit that transmits the diagnosis result of the performance of the battery B by the CPU 10 to the external server device S.

(CPU function configuration)
FIG. 3 is a diagram showing a functional configuration of a CPU according to the first embodiment.
The CPU 10 according to the present embodiment exerts functions as a first impedance acquisition unit 100, a second impedance acquisition unit 101, and a performance diagnosis unit 102 by operating according to a program prepared in advance.
The first impedance acquisition unit 100 acquires the impedance at the first frequency (0.1 Hz) of the battery B to be diagnosed.
The second impedance acquisition unit 101 acquires the impedance at the second frequency (10 Hz) of the battery B to be diagnosed.
The performance diagnosis unit 102 calculates a difference value between the impedance at the first frequency and the impedance at the second frequency (also referred to as “impedance difference value” in the following description). The performance diagnosis unit 102 measures the battery capacity of the battery B based on this impedance difference value.

(Battery equivalent circuit)
FIG. 4 is a diagram showing an equivalent circuit of the battery according to the first embodiment.
FIG. 5 is a diagram showing impedance frequency characteristics of the battery according to the first embodiment.
The equivalent circuit of the battery is represented as shown in FIG. Here, "Vocv" is the electromotive force (open end voltage) of the battery. “R0” is a resistance value based on the resistance of the terminal itself, the contact resistance, and the conductivity of the electrolytic solution (hereinafter, also referred to as “resistance value such as contact resistance”). “L” is an inductance component caused by the length and diameter of the battery terminals. “R1”, “R2”, ..., “RN” are reaction resistance values at the electrode / electrolyte interface. “C1”, “C2”, ..., “CN” are electric double layer capacitance values (hereinafter, also simply referred to as “capacity values”) based on the amount of ions adsorbed on the electrode surface.
The reaction resistance values R1, R2, ... Each form a parallel circuit (hereinafter, also referred to as "R / C parallel circuit") with the capacitance values C1, C2, .... Each R / C parallel circuit, resistance value R0 such as contact resistance, and inductance component L are in a series connection relationship.
Among the above parameters, the parameters having a high correlation with the battery performance (battery capacity) are the reaction resistance values R1, R2, ..., RN. As a result of examining the relationship between the battery capacity of various deteriorated batteries (lead batteries) and impedance measurement, the present inventors have a significant correlation between these reaction resistance values and the battery capacity, and a more appropriate frequency. It was found that the difference value between the two impedance values (hereinafter, also referred to as “difference impedance”) shows a strong correlation. FIG. 6 shows an example of the relationship between the measured impedance value at each frequency and the battery capacity actually obtained by the present inventor. Further, the difference in impedance at each frequency shown in FIG. 6 is shown in FIGS. 7A and 7B. The target battery (lead battery) is a clad type lead battery for an electric vehicle having a nominal capacity of 280 Ah. In the differential impedance shown in FIG. 7A, it can be seen that the relationship with the battery capacity has a negative correlation over almost the entire battery capacity range (the larger the differential impedance, the smaller the battery capacity of the battery). When the relationship between the two was approximated by an exponential approximation formula (y = A × expBX), it was confirmed that the correlation coefficient showed a high correlation of about 0.93 or more (see FIG. 7B). In FIGS. 7A and 7B, for example, the legend "Z0.1Hz-Z1Hz" indicates the difference value between the impedance of the frequency 0.1Hz and the impedance of the frequency 1Hz.
On the other hand, the resistance value R0 such as contact resistance is a parameter having a low correlation with the performance of the battery, but it easily fluctuates depending on the usage environment of the battery and causes an error in impedance measurement.

Based on the above equivalent circuit, the impedance frequency characteristics of the battery can be schematically shown as shown in FIG.
That is, at a low frequency (for example, f1 = 0.1 Hz), the capacitance values C1, C2, ..., and CN all have extremely high impedances, so that the impedance of the battery is the impedance of all the resistance values connected in series. The total sum is RA (RA = R0 + R1 + R2 + ... + RN).
On the other hand, at a high frequency (for example, f2 = 10 Hz), the impedance of some of the capacitance values C1, C2, ..., CN is reduced to the extent that it can be regarded as a conductor. The capacitance value C that can be regarded as a conductor and the resistance value R that forms an R / C parallel circuit do not contribute to the impedance of the battery. Therefore, the impedance RP of the battery at the frequency f2 can be expressed as RP = R0 + R1 + ... + RK (K <N).
Further, at a higher frequency, all of the capacitance values C1, C2, ..., CN can be regarded as a conductor. Then, the impedance of the battery becomes only the resistance value R0 such as the contact resistance, and takes the minimum value.

Note that in a frequency band higher than the frequency that takes the minimum value (for example, around 100 Hz), the inductance component L becomes dominant and the impedance rises as the frequency increases, so the performance of the battery cannot be evaluated.

(Processing flow)
FIG. 8 is a diagram showing a processing flow executed by the CPU according to the first embodiment.
FIG. 9 is a diagram showing an example of a battery capacity table according to the first embodiment.
Hereinafter, the processing flow of the battery diagnostic apparatus according to the first embodiment will be described in detail with reference to FIGS. 8 to 9 in addition to FIG.

The first impedance acquisition unit 100 of the CPU 10 first operates the selector 13 to enable the transmission circuit 12A (for example, an output signal having a frequency f1 = 0.1 Hz) and obtain a measurement signal from the impedance measurement circuit 14. .. Then, the first impedance acquisition unit 100 measures the impedance Z (f1) of the battery B at the frequency f1 (step S01).

Next, the second impedance acquisition unit 101 of the CPU 10 operates the selector 13 to enable the transmission circuit 12B (for example, an output signal having a frequency f2 = 10 Hz) and obtain a measurement signal from the impedance measurement circuit 14. Then, the second impedance acquisition unit 101 measures the impedance Z (f2) of the battery B at the frequency f2 (step S02).

Next, the performance diagnosis unit 102 of the CPU 10 calculates the difference between the impedance Z (f1) and the impedance Z (f2) (impedance difference value Zd = Z (f1) −Z (f2)) (step S03).

Further, the performance diagnosis unit 102 calculates the battery capacity of the battery B based on the impedance difference value Zd calculated in step S03 (step S04). Specifically, the performance diagnosis unit 102 refers to the battery capacity table T1 as shown in FIG. 9 and specifies the battery capacity corresponding to the impedance difference value Zd.
It is assumed that the relationship between the impedance difference value Zd and the battery capacity as shown in the battery capacity table T1 is prepared in advance by measurement or simulation performed in advance.
Further, in another embodiment, the relationship between the impedance difference value Zd and the battery capacity may be defined by an approximate expression instead of the mode of the information table.

(Action, effect)
The actions and effects obtained by the processing of the battery diagnostic apparatus 1 as described above will be described in detail again with reference to FIG. In FIG. 5, graph a shows the frequency characteristics of impedance in the initial state of the battery B, and graph b shows the frequency characteristics of impedance in the state after using the battery B for a predetermined period of time.

As shown in FIG. 5, there is a measurement error between the graph a and the graph b due to the difference between the resistance value R0 (a) and the resistance value R0 (b). Therefore, even if the absolute values of the graph a and the graph b at a specific frequency are compared, the performance of the battery B cannot be evaluated correctly due to the measurement error. However, in the present embodiment, the impedance difference value Zd, which is the difference value between the impedance Z (f1) at the frequency f1 (for example, 0.1 Hz) and the impedance Z (f2) at the frequency f2 (for example, 10 Hz), is compared. It is said. Here, the impedance difference value Zd does not include an element having a resistance value R0 such as a contact resistance, and is composed of an element (R1 + R2 + ... + RK) having a high correlation with the performance of the battery B. Therefore, by comparing the impedance difference value Zd (a) in the initial stage with the impedance difference value Zd (b) after use for a predetermined period, it is possible to accurately evaluate the change (deterioration) in the performance of the battery B.

As described above, according to the battery diagnostic device 1 according to the first embodiment, the battery performance can be diagnosed with high accuracy.

Further, in the first embodiment, the first frequency f1 and the second frequency f2 are at least frequencies lower than the frequency band in which the inductance component L of the battery B is dominant (see FIG. 5).
By doing so, the impedance is measured in a frequency band that is not affected by the inductance component L, so that elements (R1 + R2 + ... + RK) that have a high correlation with the performance of the battery B can be extracted more accurately. ..

<Second embodiment>
Next, the battery diagnostic device according to the second embodiment and the forklift provided with the battery diagnostic device will be described with reference to FIGS. 10 to 12.

(Battery diagnostic device configuration)
FIG. 10 is a diagram showing a configuration of a battery diagnostic device according to a second embodiment.

As shown in FIG. 10, the battery diagnostic device 1 according to the second embodiment further has a temperature sensor TS in addition to the configuration of the first embodiment. The temperature sensor TS may be, for example, a K-type or T-type thermocouple, a thermistor, a contact-type temperature sensor such as a platinum resistance thermometer, a non-contact temperature sensor using infrared rays, or the like. The temperature sensor TS is arranged in the vicinity of the battery B so that the temperature of the battery B can be acquired. The temperature detection signal from the temperature sensor TS is input to the CPU 10.

Further, the temperature compensation table T2 is further recorded in the memory 15 according to the second embodiment. A specific embodiment of the temperature compensation table T2 will be described later.

(CPU function configuration)
FIG. 11 is a diagram showing a functional configuration of the CPU according to the second embodiment.
As shown in FIG. 11, the CPU 10 of the battery diagnostic device 1 according to the second embodiment further includes a temperature compensation unit 103 in addition to the configuration of the first embodiment.

The temperature compensation unit 103 has an impedance Z (f1) at the first frequency f1 and a second temperature based on the temperature of the battery B to be diagnosed (the temperature acquired based on the temperature detection signal of the temperature sensor TS). The impedance Z (f2) at the frequency f2 is compensated.

(Processing of temperature compensation unit)
FIG. 12 is a diagram showing an example of a temperature compensation table according to the second embodiment.
The process of the temperature compensation unit 103 of the CPU 10 will be described in detail with reference to FIG.
The temperature compensation table T2 shown in FIG. 12 shows the difference value between the temperature of the battery B, the impedance at the reference temperature (for example, 25 ° C.) and the impedance actually measured (hereinafter, also referred to as the impedance difference value for each temperature). It is a figure which shows the relationship of. Since the relationship between the temperature of the battery B and the impedance difference value for each temperature differs for each frequency, it is defined for each frequency (f1, f2) to be measured.
When the temperature compensation unit 103 acquires the temperature of the battery B through the temperature sensor TS, the temperature compensation unit 103 refers to the temperature compensation table T2 and specifies the impedance difference value for each temperature corresponding to the temperature of the battery B. Then, the temperature compensation unit 103 adds or subtracts the temperature-specific impedance difference value from the actually measured impedance (measured impedance). By doing so, the measured impedance is converted into the impedance (compensation impedance) at the reference temperature (for example, 25 ° C.).

In another embodiment, the compensation impedance is acquired by calculating the equation (1) using the compensation count K (parameter corresponding to the slope of the graph shown in FIG. 12) defined in advance for each frequency. It may be a thing.

Zs = Zm + K (Tm-Ts) ... (1)

Here, "Zs" is the compensation impedance, "Zm" is the measurement impedance, "Tm" is the temperature of the battery B, and "Ts" is the reference temperature.

(Action, effect)
As described above, the temperature compensation makes it possible to estimate the battery performance with higher accuracy.

<Other Embodiments>
The battery diagnostic device 1 according to the first and second embodiments has been described in detail above, but the specific embodiment of the battery diagnostic device 1 is not limited to the above and does not deviate from the gist. It is possible to make various design changes within.

The battery diagnostic device 1 according to the first and second embodiments has been described in the embodiment provided in the forklift F, but the other embodiments are not limited to this. For example, as shown in FIG. 13, the battery diagnostic device 1 may be provided in the charger E, which is the charging stand of the forklift F. In this case, the battery diagnostic device 1 diagnoses the performance of the battery B via the connection cable of the charger E.
By doing so, the environment of the battery B at the time of performance diagnosis can be fixed, so that the influence of environment-dependent disturbance can be suppressed.

Further, the battery diagnostic device 1 according to another embodiment may further have a function of controlling the timing of performing the performance diagnosis of the battery B.
For example, the battery diagnostic device 1 may perform performance diagnosis at a timing when the battery B is not charging / discharging in the forklift F. In addition, the performance diagnosis may be performed at a timing after a predetermined time has elapsed from the completion of charging.
By doing so, the influence of disturbance in the performance diagnosis can be further suppressed.

Further, the battery diagnostic device 1 according to the above embodiment has been described as having the battery B mounted on the forklift F as a diagnostic target, but the other embodiments are not limited to this mode. That is, in another embodiment, the battery diagnostic device 1 may target a battery mounted on a moving body (for example, a general electric vehicle, a hybrid car, etc.) other than a forklift. A battery that is fixedly installed (not mounted on a moving body) may be the target of diagnosis.

In the above-described embodiment, the processes of various processes of the diagnostic apparatus 1 are stored in a computer-readable recording medium in the form of a program, and the various processes are performed by the computer reading and executing this program. .. The computer-readable recording medium refers to a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like. Further, this computer program may be distributed to a computer via a communication line, and the computer receiving the distribution may execute the program.

The above program may be for realizing a part of the above-mentioned functions. Further, it may be a so-called difference file (difference program) that can realize the above-mentioned function in combination with a program already recorded in the computer system.

As described above, some embodiments according to the present disclosure have been described, but all of these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and variations thereof are included in the scope of the invention described in the claims and the equivalent scope thereof, as are included in the scope and gist of the invention.

<Additional notes>
The diagnostic device 1, the forklift F, the charger E, and the like described in each embodiment are grasped as follows, for example.

(1) The battery diagnostic apparatus 1 according to the first aspect includes a first impedance acquisition unit 100 that acquires an impedance Z (f1) at a first frequency f1 of the battery B to be diagnosed, and a second battery B. The battery is based on the difference value Zd between the second impedance acquisition unit 101 that acquires the impedance Z (f2) at the frequency f2 and the impedance Z (f1) at the first frequency and the impedance Z (f2) at the second frequency. A performance diagnosis unit 102 for diagnosing the performance of B is provided.

(2) In the battery diagnostic apparatus 1 according to the second aspect, the performance diagnostic unit 102 diagnoses the performance of the battery based on the relationship that the battery capacity of the battery decreases as the impedance difference value increases.

(3) In the battery diagnostic apparatus 1 according to the third aspect, the first frequency and the second frequency are at least frequencies lower than the frequency band in which the inductance component of the battery B is dominant.

(4) The battery diagnostic device 1 according to the fourth aspect further includes a temperature compensating unit 103 that compensates for the impedance at the first frequency and the impedance at the second frequency based on the temperature of the battery B.

(5) The forklift F according to the fifth aspect includes the diagnostic device 1 according to any one of the above (1) to (4) and the battery B.

(6) The charger according to the sixth aspect includes the diagnostic device 1 according to any one of (1) to (4) above.

(7) The battery diagnosis method according to the seventh aspect includes a step of acquiring the impedance Z (f1) at the first frequency f1 of the battery B to be diagnosed and the impedance Z (f1) at the second frequency f2 of the battery B. It has a step of acquiring f2) and a step of diagnosing the performance of the battery B based on the difference value Zd between the impedance Z (f1) at the first frequency and the impedance Z (f2) at the second frequency. ..

(8) The program according to the eighth aspect includes a step of acquiring the impedance Z (f1) at the first frequency f1 of the battery B to be diagnosed by the computer of the battery diagnostic device 1, and a second step of the battery B. The performance of the battery B is diagnosed based on the step of acquiring the impedance Z (f2) at the frequency f2 and the difference value Zd between the impedance Z (f1) at the first frequency and the impedance Z (f2) at the second frequency. Steps to do and to execute.

According to each of the above embodiments, the battery performance can be diagnosed with high accuracy.

1 Battery diagnostic device 10 CPU
100 1st impedance acquisition unit 101 2nd impedance acquisition unit 102 Performance diagnosis unit 103 Temperature compensation unit 11

Power supply circuit

12A, 12B Oscillation circuit 13 Selector 14 Impedance measurement circuit 15 Memory 16 Transceiver F Forklift S Server device E Charger B Battery (lead) battery)
T1 Battery capacity table T2 Temperature compensation table

Claims

A first impedance acquisition unit that acquires impedance at the first frequency of the battery to be diagnosed, and
A second impedance acquisition unit that acquires impedance at the second frequency of the battery, and
A performance diagnosis unit that diagnoses the performance of the battery based on the difference value between the impedance at the first frequency and the impedance at the second frequency.
Battery diagnostic device equipped with.
The battery diagnostic device according to claim 1, wherein the performance diagnosis unit diagnoses the performance of the battery based on the relationship that the battery capacity of the battery decreases as the difference value increases.
The battery diagnostic apparatus according to claim 1 or 2, wherein the first frequency and the second frequency are at least frequencies lower than the frequency band in which the inductance component of the battery is dominant.
The battery according to any one of claims 1 to 3, further comprising a temperature compensating unit that compensates for the impedance at the first frequency and the impedance at the second frequency based on the temperature of the battery. Diagnostic device.
The diagnostic device according to any one of claims 1 to 4.
With the battery
Forklift equipped with.
A charger including the diagnostic device according to any one of claims 1 to 4.
The step of acquiring the impedance at the first frequency of the battery to be diagnosed, and
The step of acquiring the impedance at the second frequency of the battery and
A step of calculating the battery capacity or the degree of deterioration of the battery based on the difference value between the impedance at the first frequency and the impedance at the second frequency.
Battery diagnostic method with.
On the computer of the battery diagnostic device,
The step of acquiring the impedance at the first frequency of the battery to be diagnosed, and
The step of acquiring the impedance at the second frequency of the battery and
A step of calculating the battery capacity or the degree of deterioration of the battery based on the difference value between the impedance at the first frequency and the impedance at the second frequency.
A program that executes.