WO2022230104A1

WO2022230104A1 - Battery management device and battery management method

Info

Publication number: WO2022230104A1
Application number: PCT/JP2021/016964
Authority: WO
Inventors: エムハバユミフタフラティフ; 亨河野; 博也藤本; 穣植田
Original assignee: 株式会社日立ハイテク
Priority date: 2021-04-28
Filing date: 2021-04-28
Publication date: 2022-11-03
Also published as: JPWO2022230104A1; TWI802317B; TW202242438A

Abstract

The purpose of the present invention is to provide a technology with which a degradation factor of a battery can be inferred in accordance with the charging/discharging behavior of the battery, without using specialized equipment for inferring degradation factors. A battery management device according to the present invention specifies an inflection point in voltage variation along a logarithmic time axis during a resting period in which charging or discharging of a battery is complete, and uses the voltage difference between intervals that are demarcated by the inflection point to infer (see fig. 2) a degradation factor of the battery.

Description

Battery management device, battery management method

The present invention relates to technology for managing the state of batteries.

There are various factors that cause deterioration of storage batteries. Impedance measurement is a common technique for measuring deterioration of storage batteries. By analyzing the frequency characteristics obtained by impedance measurement, the deterioration factor of the storage battery can be estimated. This is because the frequency characteristic fluctuates in response to deterioration factors. The following non-patent document 1 describes a technique related to impedance measurement of a lithium ion battery.

　In order to perform impedance measurement, an AC wave must be applied to the object. Therefore, it is difficult to measure the impedance in the process of simply charging and discharging the storage battery because equipment for that purpose is required. This is because the charging and discharging of a storage battery is a DC process. If the deterioration factor of the storage battery can be estimated in the charging/discharging process of the storage battery, it is useful because it eliminates the need to prepare equipment for impedance measurement.

Also, in Non-Patent Document 1, an equivalent circuit that models a storage battery is used. However, it is difficult to design an equivalent circuit that generally models various batteries because the characteristics of batteries vary depending on the model number of the battery, the characteristics of the electrodes, and the like.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and can estimate deterioration factors associated with charging and discharging operations of a battery without using dedicated equipment for estimating battery deterioration factors. The purpose is to provide technology.

The battery management device according to the present invention identifies an inflection point of voltage change on a logarithmic time axis in a rest period when the battery finishes charging or discharging, and uses the voltage difference in the section delimited by the inflection point. , to estimate deterioration factors of the battery.

According to the battery management device according to the present invention, it is possible to estimate deterioration factors associated with battery charge/discharge operations without using dedicated equipment for estimating battery deterioration factors.

4 is a graph illustrating temporal changes in output voltage before and after the storage battery completes discharging operation; It is a figure explaining the inflection point in the time-dependent change of the output voltage in a rest period. It is an example of relationship data describing the relationship between the output voltage slope on the logarithmic time axis and the degree of progress of deterioration factors. It is a figure which shows the modification of relational data. 4 is a flowchart for explaining a procedure for calculating the degree of progression of deterioration factors; FIG. 4 is a diagram for explaining a procedure for estimating the generation of a battery using deterioration factors of the battery; 10 is a flowchart for explaining the procedure for calculating the degree of progression of deterioration factors of a battery in Embodiment 2. FIG. FIG. 11 is a schematic diagram illustrating an application of the battery management device according to Embodiment 3; FIG. 11 is a diagram showing a configuration example of a battery management device 100 according to Embodiment 3; 4 is a diagram showing another configuration example of the battery management device 100. FIG. A configuration example in which the detection unit 130 is connected to the battery 200 is shown. 4 is a flowchart for explaining a procedure for calculation of SOH by a calculation unit 120; 4 is a graph showing temporal changes in the current and voltage output by the battery 200 during a rest period after discharging. 4 is a graph showing temporal changes in current and voltage output by the battery 200 during a rest period after charging. 4 is a diagram showing the structure of a relationship table 141 and an example of data; FIG. It is an example of a user interface presented by the battery management device 100 .

<Embodiment 1>
FIG. 1 is a graph illustrating temporal changes in output voltage before and after a storage battery completes discharging operation. In the idle period after the discharge operation is completed, the output voltage of the battery changes with time as shown in FIG. The inventors have found that the output voltage changes with time during the pause period, and voltage changes corresponding to deterioration factors of the storage battery appear.

FIG. 2 is a diagram for explaining the inflection point in the change over time of the output voltage during the pause period. The point of inflection here appears when the temporal change of the output voltage as shown in FIG. 1 is represented on the logarithmic time axis. As shown in FIG. 2, there is a remarkable difference between the slope of the output voltage of a new battery and the slope of the output voltage of a degraded battery in the sections sandwiched by the inflection points on the logarithmic time axis. The present inventor focused on the slope in each section and decided to estimate the deterioration factor of the battery.

Time on the logarithmic time axis can be divided into multiple sections by inflection points. These sections are considered to correspond to deterioration factors of the battery. For example, in the frequency characteristics of impedance measurement, values in specific frequency bands fluctuate in response to deterioration factors. In other words, it is considered that the variation in the impedance measurement result in a specific frequency band corresponds to the deterioration factor. On the other hand, it can be considered that what corresponds to the frequency component of the impedance measurement in FIG. 2 is the time range on the logarithmic time axis. For example, when the frequency component changes by one digit, the time on the logarithmic time axis changes by one scale. Therefore, in the present invention, the logarithmic time axis is divided into one or more sections, and it is assumed that the slope of each section correlates with the deterioration factor.

　The section on the logarithmic time axis can be determined by performing impedance measurement in advance and identifying the section where the characteristics of the deterioration factors are well represented. However, since the characteristic of the deterioration factor is well expressed in the slope of the output voltage on the logarithmic time axis, in actual processing, for example, the point where the output voltage on the logarithmic time axis is differentiated three times and becomes 0 is the inflection point. , and it can be considered that the deterioration factor corresponds to each section divided by the inflection point. Therefore, in the following description, it is assumed that sections on the logarithmic time axis are divided by inflection points.

As shown in the enlarged view of section 1 in FIG. 2, there is a significant difference between the output voltage slope of a new battery and the output voltage slope of a deteriorated battery in the sections divided by the inflection points. Therefore, the degree of progression of the deterioration factor is estimated by obtaining this slope and referring to relational data described later using the slope. In the following description, the slope of section 1 is m_1, the slope of section 2 is m_2, and so on.

FIG. 3 is an example of relationship data describing the relationship between the output voltage slope on the logarithmic time axis and the degree of progression of deterioration factors. Relational data is defined for each section on the logarithmic time axis. For example, the data in the upper part of FIG. 3 describes the relationship between the slope m_1 of the output voltage in section 1 and the progress of deterioration factor 1 corresponding to section 1 . The data in the lower part of FIG. 3 describe the interval 2 and the deterioration factor 2 in the same way. Further, similar data may be prepared for each type of battery (for example, type distinguished by battery model number, electrode material, etc.), and relational data corresponding to the battery type may be used. Each deterioration factor is a factor that can be quantified, such as the degree of deterioration of the positive electrode material.

The slope m_1 can be calculated by the difference in output voltage between the start and end of interval 1. A function representing the relationship between m_1 and the progress of deterioration factor 1 may be defined in advance on the relationship data. By applying m_1 to the function, the progress of deterioration factor 1 can be calculated. The deterioration factor 2 can also be similarly calculated from the slope m_2. A function representing the relationship between the slope and the deterioration factor can be defined for each combination of the deterioration factor and the section (that is, the functions do not have to be the same).

FIG. 4 is a diagram showing a modified example of relational data. The function representing the relationship between the voltage slope and the deterioration factor may change depending on at least one of the battery temperature T, the battery discharge current I, and the battery discharge end voltage V. In that case, function parameters are defined in advance for each value of T, each value of I, and each value of V, and the degree of progression of the deterioration factor is calculated using the function parameters corresponding to these actually measured values. Just do it. Therefore, the function f representing the relationship between the voltage gradient and the degree of progression of deterioration factors in this case is defined as follows.

deterioration factor n=f(
m_n,
c_Rn_T_1, c_Rn_T_2, ...,
c_Rn_I_1, c_Rn_I_2, ...,
c_Rn_V_1, c_Rn_V_2, ...
)

The deterioration factor n is a function of the slope m_n of the output voltage in section n. The function f further includes one or more parameters c_Rn_T that vary according to the temperature T. Similarly, one or more parameters c_Rn_I that change according to the current I and c_Rn_V that change according to the voltage V are included.

FIG. 5 is a flowchart explaining the procedure for calculating the degree of progression of deterioration factors. Each step in FIG. 5 will be described below.

(Fig. 5: Step S501)
It is determined whether it is a rest period after charging or a rest period after discharging. If the current period is not the rest period, the flow chart ends. If it is the pause period, the process proceeds to S502. For example, in the rest period after discharge, the current output by the battery changes from a negative value (I<0) toward zero, and (b) changes from a negative value to a value near zero and stabilizes. (|I|<threshold).

(Fig. 5: Step S501: Supplement)
When function parameters are defined for each value of T, each value of I, and each value of V, as described with reference to FIG. 4, these values may be acquired in this step (or a step to be described later). These values can be obtained, for example, from a management unit arranged for each battery cell.

(Fig. 5: Step S502)
Acquire the change over time of the output voltage in the pause period. Furthermore, an inflection point is specified when the acquired change over time is expressed on a logarithmic time axis. The slope of the output voltage (the voltage difference from the start point to the end point of the section) is calculated for each section divided by the inflection points. Let these be slopes m_1 to m_n.

(Fig. 5: Step S503)
Relational data corresponding to each section is obtained. By applying the gradient in each section to the function described by the relational data, the degree of progression of the deterioration factor corresponding to that section is calculated. Similarly, the degree of progression of deterioration factors is obtained for each section.

<Embodiment 1: Summary>
According to the first embodiment, by specifying an inflection point on the logarithmic time axis of the output voltage in the rest period of the battery and referring to the relational data using the slope of the section divided by the inflection point, the Estimate the degree of progress of the deterioration factor corresponding to the section. By estimating the deterioration factor using the temporal change of the output voltage during the rest period, it is not necessary to separately prepare equipment for impedance measurement or the like, so the deterioration factor can be easily estimated. Further, by specifying an inflection point on the logarithmic time axis, it is possible to specify a section in which the characteristic of the deterioration factor is well expressed, and accurately estimate the deterioration factor according to the characteristic of the section.

<Embodiment 2>
A typical deterioration factor of batteries is the deterioration of the materials (eg, cathode materials) forming the components of the battery. The degree of deterioration of a component varies depending on the material forming the component, and which material is used depends on the progress of technological development of the battery. That is, it is conceivable that the generation of the battery (or information such as the model number representing the generation) of the battery can be estimated by obtaining the voltage gradient representing the characteristics of the material forming the part. Embodiment 2 of the present invention describes the procedure.

FIG. 6 is a diagram explaining the procedure for estimating the generation of the battery using the deterioration factor of the battery. As described in the first embodiment, sections on the logarithmic time axis correspond to battery deterioration factors. Among these deterioration factors, those from which the generation of the battery can be estimated are specified. For example, since the positive electrode material corresponds to the generation of the battery, the slope m_x of the section x corresponding to the degree of deterioration of the positive electrode material can be used as information for estimating the generation of the battery.

For example, the generation of the battery can be estimated by calculating the variation range of the slope m_x in the section x and preparing data representing the relationship between the variation range and the generation of the battery in advance. One example is shown in FIG.

FIG. 7 is a flowchart for explaining the procedure for calculating the degree of progression of battery deterioration factors in the second embodiment. S601 is performed between S502 and S503 in FIG. Others are the same as in FIG.

In S601, the relationship data is referenced using the deterioration factor representing the generation of the battery and the slope m_x of the corresponding section x. The relationship data describes the relationship between the value range of the slope m_x (or the progress of the deterioration factor calculated by the value range) and the generation of the battery. This makes it possible to estimate the generation of the battery.

<Embodiment 3>
Embodiment 3 of the present invention will explain a configuration example of a battery management apparatus in which the method of estimating the battery deterioration factor explained in

Embodiments

1 and 2 is implemented.

FIG. 8 is a schematic diagram illustrating an application of the battery management device according to the third embodiment. The battery management device estimates the deterioration factor of the battery according to the procedure of each flowchart described in the first and second embodiments. Batteries (eg, battery cells, battery modules, battery packs, etc.) that need to be charged and discharged are connected to various devices. For example, a tester, a BMS (Battery Management System), a charger, and the like. The battery is either in charging/discharging/resting state when connected to these devices. Depending on where the algorithm for calculating the degradation factor is implemented, the degradation factor can be calculated, for example, on the device described above, or on a computer connected via a network, such as on a cloud server. . The advantage of computing on the device to which the battery is connected is that the battery status (voltage output by the battery, current output by the battery, temperature of the battery, etc.) can be obtained frequently.

The deterioration factor calculated on the cloud system can also be sent to the computer owned by the user. The user computer can provide this data for specific uses, such as inventory management. The deterioration factor calculated on the cloud system can be stored in the cloud platform provider's database and used for other purposes. For example, optimization of replacement routes for electric vehicles, energy management, and so on.

FIG. 9 is a diagram showing a configuration example of the battery management device 100 according to the third embodiment. In FIG. 9, a battery management device 100 is a device that is connected to a battery 200 and receives power from the battery 200, and corresponds to the tester or the like in FIG. The battery management device 100 includes a communication section 110 , a calculation section 120 , a detection section 130 and a storage section 140 .

The detection unit 130 acquires the detected value V of the voltage output by the battery 200 and the detected value I of the current output by the battery 200 . Furthermore, as an option, the detected value T of the temperature of the battery 200 may be obtained. These detection values may be detected by battery 200 itself and notified to detection unit 130 , or may be detected by detection unit 130 . Details of the detection unit 130 will be described later.

The calculation unit 120 estimates the deterioration factor of the battery 200 using the detection value acquired by the detection unit 130 . The estimation procedure is the one described in the first and second embodiments. The communication unit 110 transmits the deterioration factor estimated by the calculation unit 120 to the outside of the battery management device 100 . For example, they can be transmitted to a memory provided by the cloud system. The storage unit 140 stores the relationship data described in the first and second embodiments.

The arithmetic unit 120 can be configured by hardware such as a circuit device that implements the function, or by executing software that implements the function by an arithmetic unit such as a CPU (Central Processing Unit). can.

FIG. 10 is a diagram showing another configuration example of the battery management device 100. As shown in FIG. The battery management device 100 does not necessarily have to be directly connected to the battery 200 to receive power supply, and shows a configuration in which the communication unit 110 and the detection unit 130 shown in FIG. 9 are not included. . In FIG. 10 , battery management device 100 acquires voltage V, current I, and temperature T of battery 200 from communication unit 110 . Specifically, the detection unit 150 included in the battery management apparatus 100 receives these detection values via, for example, a network, and the calculation unit 120 uses these detection values to calculate deterioration factors.

FIG. 11 shows a configuration example when the detection unit 130 is connected to the battery 200. FIG. The detection unit 130 may be configured as part of the battery management device 100 or may be configured as a module separate from the battery management device 100 . The detection unit 130 includes a voltage sensor 131, a temperature sensor 132, and a current sensor 133 in order to obtain the voltage V, temperature T, and current I when the battery 200 is charged and discharged.

The voltage sensor 131 measures the voltage across the battery 200 (the voltage output by the battery 200). The temperature sensor 132 is connected to, for example, a thermocouple included in the battery 200 and measures the temperature of the battery 200 via this. Current sensor 133 is connected to one end of battery 200 and measures the current output by battery 200 . Temperature sensor 132 is optional and need not be provided.

<Embodiment 4>
In the above embodiment, the SOH of battery 200 may be estimated by calculation unit 120 . However, in order to estimate the SOH, it may take a long time for the measured value to stabilize. Therefore, in Embodiment 4 of the present invention, a configuration example for measuring SOH in a short time by a simple means will be described. The configuration of each device is the same as that of the third embodiment.

FIG. 12 is a flow chart explaining the procedure for calculating the SOH by the calculation unit 120. FIG. The calculation unit 120 starts this flowchart at an appropriate timing such as, for example, when the battery management device 100 is activated, when instructed to start this flowchart, or at predetermined intervals. Each step in FIG. 12 will be described below.

(Fig. 12: Step S1201)
Arithmetic unit 120 determines whether it is a rest period after charging or a rest period after discharging. If the current period is not the rest period, the flow chart ends. If it is the pause period, the process proceeds to S1202. For example, a rest period after discharging means that the current output by the battery 200 changes from a negative value (I<0) toward zero, and (b) changes from a negative value to a value near zero and stabilizes. (|I|<threshold), or the like.

(Fig. 12: Step S1202)
The calculator 120 calculates ΔVa and ΔVb. ΔVa is the amount of change in the output voltage of the battery 200 from the first calculation time after the end of the rest period to the first time when the first period ta has passed. ΔVb is the amount of change in the output voltage of battery 200 from the second time point after the first time point to the second time point after the second period tb has passed. These calculation procedures will be described later.

(Fig. 12: Step S1203)
The calculator 120 calculates the internal resistance Ri and SOH of the battery 200 according to

Equations

1 and 2 below. f _Ri defines Ri as a function of ΔVa. f _Ri has a parameter (c_Ri_T) that varies with the temperature of the battery 200 and a parameter (c_Ri_I) that varies with the output current of the battery 200 . f _SOH defines SOH as a function of ΔVb. f _SOH has a parameter (c_SOH_T) that varies with the temperature of the battery 200 and a parameter (c_SOH_I) that varies with the output current of the battery 200 . These parameters are defined by the relationship table 141 stored in the storage unit 140. FIG. A specific example of each function and a specific example of the relationship table 141 will be described later. _fRi and _fSOH are formulas formed based on, for example, experimental data for each lot.

(Fig. 12: Step S1203: Formula)
_Ri =fRi (ΔVa, c_Ri_T_1, c_Ri_T_2, ..., c_Ri_I_1, c_Ri_I_2, ...) (1)
SOH = f _SOH (ΔVb, c_SOH_T_1, c_SOH_T_2, ..., c_SOH_I_1, c_SOH_I_2, ...) (2)

FIG. 13 is a graph showing temporal changes in the current and voltage output by the battery 200 during the rest period after discharging. ΔVa in S1202 is the amount of change in the output voltage of battery 200 from the time when discharging is completed or after the first calculation time to the first time when the first period ta has passed. The inventors have found that the output voltage immediately after the end of discharging clearly shows the voltage fluctuation due to the internal resistance of the battery 200 . That is, it can be said that the fluctuation (ΔVa) of the output voltage during this period has a strong correlation with Ri. In the present embodiment, this fact is used to estimate Ri by ΔVa. The optimum values for the start time and the time length of ta can be obtained based on the section from the end of discharge to the maximum point of the slope change rate in the voltage change curve over time. When specifying the above-mentioned section, depending on the type of battery, the device, the accuracy, etc., it is possible to select a region in the vicinity of both ends of the above-mentioned section, or an area including both ends.

The start time of ta does not necessarily have to be the same as the discharge end time, but it is desirable that it be close to the discharge end time. The start time of tb does not necessarily have to be the same as the end time of ta. In either case, ta and tb have a relationship of ta<tb. Regarding the magnitude of ΔVa and the magnitude of ΔVb, ΔVa may be larger, and ΔVb may be larger. Although ta<tb is set here, there may be a case where ta>tb or ta=tb depending on the type of battery, the device, the accuracy, etc. Therefore, a preferable relationship may be set as appropriate.

Experimental results by the inventors have shown that Ri and SOH can be accurately estimated even if the sum of ta and tb is, for example, several seconds. Therefore, according to the present embodiment, both Ri and SOH can be quickly estimated during the idle period.

FIG. 14 is a graph showing temporal changes in the current and voltage output by the battery 200 during the rest period after charging. ΔVa in S1202 may be the change in the output voltage of the battery 200 from the time when the charging is finished or after the first calculation time to the first time when the first period ta has passed, instead of the discharge. In this case, ΔVb in S1202 is the change in the output voltage of the battery 200 from the time when the period ta has passed or the second starting time after that until the second time when the second period tb has passed. The present inventors have found that ΔVa has a correlation with Ri and ΔVb has a correlation with SOH even in the rest period after charging. Therefore, in this embodiment, ΔVa and ΔVb in S1202 may be obtained after either charging or discharging.

FIG. 15 is a diagram showing the structure of the relationship table 141 and an example of data. The relationship table 141 is a data table that defines each parameter in

Equations

1 and 2. Since c_Ri_I and c_SOH_I vary depending on the output current of the battery 200, they are defined for each output current value. Since c_Ri_T and c_SOH_T vary depending on the temperature of the battery 200, they are defined for each temperature. Since these parameters may have different characteristics between the rest period after discharging and the rest period after charging, the relationship table 141 defines each parameter for each of these periods. The relationship table 141 may be configured as part of the relationship table described in the first and second embodiments, or may be configured as separate data.

When fRi is a linear function of ΔVa, _Ri can be expressed, for example, by Equation 3 below. This is because the slope of Ri is affected by temperature and the intercept is affected by current. In this case, c_Ri_T and c_Ri_I are each one.

　Ri=c_Ri_T_1×ΔVa+c_Ri_I_1 (3)

When f _SOH is a linear function of ΔVb, SOH can be expressed by Equation 4 below, for example. This is because the slope of SOH is affected by temperature and the intercept is affected by current. In this case, c_SOH_T and c_SOH_I are each one.

　SOH=c_SOH_T_1×ΔVb+c_SOH_I_1 (4)

16 is an example of a user interface presented by the battery management device 100. FIG. A user interface can be presented on a display device, such as a display device. The user interface presents the calculation result by the calculation unit 120 . In FIG. 16, along with presenting the change over time of the output voltage on the logarithmic time axis, the three deterioration factors of positive electrode material contact resistance/negative electrode resistance/positive charge transfer resistance are exemplified. Furthermore, the result of estimating the state of deterioration of the battery can also be presented.

<Regarding Modifications of the Present Invention>
The present invention is not limited to the embodiments described above, and includes various modifications. For example, the above-described embodiments have been described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations described. Also, part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Moreover, it is possible to add, delete, or replace part of the configuration of each embodiment with another configuration.

In the above embodiment, the identification of the inflection point on the logarithmic time axis has been described, but in order to identify this inflection point, the time axis does not necessarily have to be converted to logarithm. In other words, it is sufficient if the point of inflection that appears when it is assumed that the change over time of the output voltage is plotted on the logarithmic time axis can be specified by some procedure.

In the above embodiment, it was explained that the deterioration factor is estimated in the idle period after the discharge operation of the storage battery. A deterioration factor can be estimated in the same manner as in the above embodiments. Whether the deterioration factor appears during the rest period after the discharge operation, the rest period after the charge operation, or both of them depends on the characteristics of the battery. Therefore, the deterioration factor may be estimated in any one of these according to the characteristics of the battery.

100: Battery management device 110: Communication unit 120: Calculation unit 130: Detection unit 140: Storage unit 200: Battery

Claims

A battery management device that manages the state of a battery,
a detection unit that acquires a detected value of the voltage output by the battery;
a computing unit that estimates the state of the battery;
with
The computing unit specifies an inflection point when the change over time of the voltage is expressed on a logarithmic time axis in a rest period after the battery finishes charging or discharging,
The calculation unit calculates the difference in the voltage in the interval within the rest period separated by the inflection point,
The computing unit acquires relational data describing the relationship between the difference and the deterioration factor of the battery,
The battery management device, wherein the calculation unit estimates the deterioration factor of the battery by referring to the relational data using the difference.
The computing unit specifies one or more of the sections by dividing the pause period by the inflection point,
The relationship data describes the relationship between the difference and the degree of progress of the deterioration factor for each combination of the section and the type of the deterioration factor,
The computing unit identifies the type of the deterioration factor corresponding to the section by referring to the relationship data using the difference in the identified section, and the degree of progress of the deterioration factor corresponding to the difference. 2. The battery management device according to claim 1, characterized by specifying:
The relational data includes parameters of a function representing a relation between the difference and the progress of the deterioration factor for each of at least one of the temperature of the battery, the output current of the battery, and the output voltage of the battery. describes,
The computing unit obtains the parameter by referring to the relational data using at least one of the temperature of the battery, the output current of the battery, or the output voltage of the battery;
The battery management device according to claim 1, wherein the calculation unit calculates the degree of progression of the deterioration factor by calculating the value of the function using the acquired parameter and the difference.
The relationship data describes materials of members forming the battery as the deterioration factor,
The battery management device according to claim 1, wherein the calculation unit estimates the material by referring to the relationship data using the difference.
The relationship data describes information specifying the material for each generation or model number of the battery,
5. The battery management device according to claim 4, wherein the calculation unit estimates the generation or model number of the battery by estimating the material.
The calculation unit calculates a value between the voltage at a first time point after the end point of charging or discharging of the battery and the voltage at a first time point after a first period has elapsed from the first time point. get 1 diff,
The computing unit obtains a second difference between the voltage at a second time point after the first time point and the voltage at a second time point after a second period has elapsed from the second time point, and
The computing unit obtains second relational data describing a relationship between the first difference and the internal resistance of the battery and describing a relationship between the second difference and the state of deterioration of the battery,
The computing unit estimates the internal resistance by referring to the second relational data using the first difference,
The battery management device according to claim 1, wherein the calculation unit estimates the deterioration state by referring to the second relationship data using the second difference.
The battery management device according to claim 1, further comprising a user interface for presenting the deterioration factor estimated by the calculation unit.
The battery management device according to claim 1, wherein the calculation unit calculates, as the difference, a slope of the voltage on the logarithmic time axis with respect to logarithmic time.
A battery management method for managing the state of a battery, comprising:
obtaining a detected value of the voltage output by the battery;
estimating the state of the battery;
with
In the estimating step, in a rest period after the battery finishes charging or discharging, an inflection point is specified when the change over time of the voltage is expressed on a logarithmic time axis,
In the estimating step, calculating the difference in the voltage in the interval within the rest period separated by the inflection point;
In the estimating step, obtaining relationship data describing the relationship between the difference and the deterioration factor of the battery,
The battery management method, wherein in the estimating step, the deterioration factor of the battery is estimated by referring to the relational data using the difference.