TWI802317B - Battery management device, battery management method - Google Patents

Abstract

An object of the present invention is to provide a technique for estimating the deterioration factor along with the charging and discharging operation of the battery without using a dedicated device for estimating the deterioration factor of the battery. The battery management device of the present invention specifies the inflection point of the voltage change on the logarithmic time axis during the rest period when the battery finishes charging or discharging, and uses the voltage difference in the interval separated by the above-mentioned inflection point, The deterioration factor of the aforementioned battery is estimated (see FIG. 2 ).

Description

Battery management device, battery management method

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

There are various causes of battery deterioration. Impedance measurement is relatively common as a method of measuring battery deterioration. The cause of battery deterioration can be estimated by analyzing the frequency characteristics obtained by impedance measurement. This is because the degradation factor corresponding to the frequency characteristic changes accordingly. The following Non-Patent Document 1 describes a technique related to impedance measurement of a lithium ion battery.

prior art literature non-patent literature

Non-Patent Document 1: Woosung Choi, et. al., "Modeling and Applications of Electrochemical Impedance", J. Electrochem. Sci. Technol., 2020, 11(1), 1-13

In order to perform impedance measurement, it is necessary to apply an AC wave to the object. Therefore, there must be equipment for its use, so it is difficult to use only the battery in the Impedance measurement is carried out during charging and discharging. The charge and discharge of the battery is due to the DC process. If it is possible to estimate the deterioration factor of the storage battery during the charging and discharging process of the storage battery, there is no need to prepare equipment for impedance measurement, which is useful.

In addition, in Non-Patent Document 1, an equivalent circuit in which a storage battery is modeled is used. However, since the characteristics of the batteries vary depending on the model of the battery, the characteristics of the electrodes, etc., it is difficult to design an equivalent circuit that generally models various batteries.

The present invention was made in view of the above-mentioned problems, and an object of the present invention is to provide a technique for estimating deterioration factors accompanying battery charging and discharging operations without using dedicated equipment for estimating battery deterioration factors.

The battery management device of the present invention specifies the inflection point of the voltage change on the logarithmic time axis during the rest period when the battery finishes charging or discharging, and uses the voltage difference in the interval separated by the above-mentioned inflection point, In order to estimate the deterioration factor of the aforementioned battery.

With the battery management device of the present invention, the deterioration factor can be estimated along with the charging and discharging operation of the battery without using special equipment for estimating the deterioration factor of the battery.

100: battery management device

110: Department of Communications

120: Computing Department

130: sensing part

131: Voltage sensor

132: Temperature sensor

133: Current sensor

140: memory department

150: sensing part

200: battery

[ Fig. 1 ] is a graph illustrating the temporal change of the output voltage before and after the discharge operation of the storage battery is completed.

[ Fig. 2] Fig. 2 is a diagram illustrating an inflection point in a temporal change of an output voltage during a rest period.

[ Fig. 3 ] is an example of relational data describing the relation between the slope of the output voltage on the logarithmic time axis and the degree of progress of the deterioration factor.

[ Fig. 4 ] is a diagram showing a modified example of relational data.

[FIG. 5] It is a flowchart explaining the procedure of calculating the progress degree of a deterioration factor.

[ Fig. 6] Fig. 6 is a diagram illustrating the order of battery generation estimation using battery deterioration factors.

[ Fig. 7] Fig. 7 is a flow chart illustrating the procedure of calculating the degree of progress of the deterioration factor of the battery in the second embodiment.

[ Fig. 8 ] is a schematic diagram illustrating an application of the battery management device according to the third embodiment.

[ Fig. 9 ] is a diagram showing a configuration example of the battery management device 100 according to the third embodiment.

[ FIG. 10 ] is a diagram showing another configuration example of the battery management device 100 .

[ FIG. 11 ] shows a configuration example when the sensor unit 130 is connected to the battery 200 .

[FIG. 12] It is a flowchart explaining the procedure which the calculation part 120 calculates SOH.

[ FIG. 13 ] is a graph showing temporal changes in the current and voltage output from the battery 200 during the rest period after discharge.

[ FIG. 14 ] is a graph showing temporal changes in current and voltage output from the battery 200 during a rest period after charging.

[FIG. 15] It is a figure which shows the structure of the relationship table 141, and a data example.

[ FIG. 16 ] is an example of the user interface presented by the battery management device 100 .

<Embodiment 1>

FIG. 1 is a graph illustrating the temporal change of the output voltage before and after the battery discharge operation is completed. During the rest period after the discharge operation is completed, the output voltage of the battery changes over time as shown in FIG. 1 . The inventors of the present invention have found that a voltage change corresponding to a deterioration factor of the storage battery appears in the temporal change of the output voltage during the rest period.

FIG. 2 is a diagram illustrating an inflection point in a temporal change of an output voltage during a rest period. The so-called inflection point here is what appears when the temporal change of the output voltage as shown in FIG. 1 is expressed on the logarithmic time axis. As shown in FIG. 2 , in the interval enclosed by the inflection point on the logarithmic time axis, the slope of the output voltage of the new battery and the slope of the output voltage of the deteriorated battery are found to be significantly different. The inventors of the present invention focused on the slopes in these intervals to estimate the cause of battery deterioration.

The time system on the logarithmic time axis can be divided into complex intervals by inflection points. These intervals are considered to correspond to factors of deterioration of the battery. For example, in the frequency characteristic of impedance measurement, the value of a specific frequency band fluctuates according to a deterioration factor. That is, the impedance measurement in a specific frequency band The fluctuation of the result is considered to correspond to the deterioration factor. On the other hand, it can be considered that the time range on the logarithmic time axis corresponds to the frequency component of the impedance measurement in FIG. 2 . For example, when the frequency component changes by 1 digit, the time on the logarithmic time axis changes by 1 division, and it is considered that there is a corresponding relationship between the two as shown above. Therefore, in the present invention, it is assumed that the logarithmic time axis is divided into sections equal to or greater than 1, and the slope of each section correlates with a deterioration factor.

The intervals on the logarithmic time axis can be set by performing impedance measurement in advance and specifying intervals that exhibit characteristics of deterioration factors well. However, the characteristics of the deterioration factor are well expressed in the slope of the output voltage on the logarithmic time axis, so in actual processing, for example, the point at which the output voltage on the logarithmic time axis is differentiated three times to become 0 It is regarded as an inflection point, and it is considered that the degradation factor corresponds to each section divided by the inflection point. Therefore, in the following description, it is assumed that intervals on the logarithmic time axis are distinguished by inflection points.

As shown in the enlarged diagram of section 1 in FIG. 2 , in the section separated by the inflection point, the output voltage slope of the new battery is significantly different from that of the degraded battery. Therefore, by obtaining the slope and using the slope, the degree of progression of the deterioration factor is estimated with reference to relational data described later. In the following description, the slope of the interval 1 is referred to as m_1, and the slope of the interval 2 is referred to as m_2, the same below.

FIG. 3 is an example of relationship data describing the relationship between the slope of the output voltage on the logarithmic time axis and the degree of progress of the degradation factor. Relational data are defined per interval on a logarithmic time axis. For example, the upper part of Figure 3 The data describes the relationship between the slope m_1 of the output voltage in the section 1 and the progress degree of the degradation factor 1 corresponding to the section 1. In the data in the lower row of FIG. 3 , Section 2 and Deterioration Factor 2 are similarly described. In addition, it is also possible to prepare the same data for each battery type (for example, the type distinguished by the battery model, electrode material, etc.), and use the relational data corresponding to the battery type. Each deterioration factor can be quantified as factors such as the degree of deterioration of the positive electrode material, for example.

The slope m_1 can be calculated by the difference of the output voltage between the start time point and the end time point of the interval 1 . The function representing the relationship between m_1 and the degree of progress of the degradation factor 1 may be defined in advance on the relationship data. By applying m_1 to this function, the degree of progress of degradation factor 1 can be calculated. The degradation factor 2 can also be calculated from the slope m_2 in the same manner. A function representing the relationship between the slope and the degradation factor may be defined for each combination of the degradation factor and the interval (that is, it may not be the same function).

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 vary depending on at least any one of the battery temperature T, the battery discharge current I, and the battery discharge end voltage V. At this time, it is sufficient to predefine function parameters for each value of T, each value of I, and each value of V, and use the function parameters corresponding to the measured values to calculate the progress of the deterioration factor. Therefore, the function f representing the relationship between the voltage gradient at this time and the degree of progress of the deterioration factor 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 degradation factor is a function of the slope m_n of the output voltage in the n-system section n. The function f system additionally includes a parameter c_Rn_T that varies with temperature T above 1. The parameter c_Rn_I that varies depending on the current I and the parameter c_Rn_V that varies depending on the voltage V also include 1 or more in the same manner.

FIG. 5 is a flowchart illustrating a procedure for calculating the progress degree of a deterioration factor. Each step in Fig. 5 will be described below.

(Figure 5: Step S501)

It is determined whether it is a rest period after charging or a rest period after discharge. If it is not a rest period now, this flow chart is ended. If it is a rest period, proceed to S502. For example, during the rest period after discharge, the current output by the battery can be changed from a negative value (I<0) towards zero, (b) from a negative value to a value near zero to stabilize (｜I|< limit) and so on.

(Figure 5: Step S501: Supplement)

If the function parameters are defined respectively by the value of each T, each I value, and each V value illustrated in Fig. 4, these equivalent values can also be obtained in this step (or steps described later). The equivalent value can be obtained, for example, by a management unit configured for each battery cell.

(Figure 5: Step S502)

The temporal change of the output voltage during the rest period is acquired. In addition, the inflection point at which the obtained change in time is expressed on the logarithmic time axis is specified. For each section divided by the inflection point, the slope of the output voltage (voltage difference from the start time point to the end time point of the section) is calculated. Let these be slopes m_1~m_n.

(Figure 5: Step S503)

Respectively obtain the relationship data corresponding to each interval. By applying the slope in each section to the function described in the relational data, the degree of progress of the deterioration factor corresponding to the section is calculated. For each section, the degree of progress of the deterioration factor is obtained in the same manner.

<Implementation 1: Summary>

According to the first embodiment, the inflection point on the logarithmic time axis of the output voltage during the rest period of the battery is specified, and the slope of the interval divided by the inflection point is used to refer to the relational data, thereby estimating the degradation corresponding to the interval The degree of progress of the cause. By estimating the deterioration factor using the temporal change of the output voltage during the rest period, it becomes unnecessary to separately prepare equipment for impedance measurement, etc., and thus the deterioration factor can be easily estimated. Furthermore, by specifying the inflection point on the logarithmic time axis, a section in which the characteristics of the deterioration factor are well exhibited is specified, and the deterioration factor can be estimated with high accuracy according to the characteristics of the section.

<Embodiment 2>

As a typical deterioration factor of a battery, the deterioration of the material (for example: positive electrode material) which comprises the component of a battery is mentioned. The degree of deterioration of a part varies depending on the material forming the part, and what material to use depends on the progress of technical development of the battery. That is, it is considered that by obtaining the voltage slope indicating the characteristics of the material forming the part, the generation of the battery (or information such as a model indicating the generation) can be estimated. The procedure is described in the second embodiment of the present invention.

FIG. 6 is a diagram illustrating the order of battery generation estimation using battery deterioration factors. As described in the first embodiment, the interval system on the logarithmic time axis corresponds to the deterioration factor of the battery. The estimated generation of the battery can be specified among the deterioration factors. For example, the positive electrode material corresponds to the generation of the battery, so the slope m_x of the interval x corresponding to the deterioration degree of the positive electrode material can be used as information for estimating the generation of the battery.

The generation of the battery can be estimated by calculating, for example, the variation range of the slope m_x in the section x, and preparing data indicating the relationship between the variation range and the generation of the battery in advance. One example thereof is shown in FIG. 6 .

FIG. 7 is a flowchart illustrating the procedure of calculating the degree of progress of the deterioration factor of the battery in the second embodiment. S601 is implemented between S502 and S503 in FIG. 5 . Other lines are the same as in Figure 5.

In S601 , the relationship data is referred to using the slope m_x of the section x corresponding to the degradation factor indicating the generation of the battery. The relational data describe 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. From this, the generation of the battery can be estimated.

<Embodiment 3>

In Embodiment 3 of the present invention, a configuration example of a battery management device incorporating the method of estimating a battery deterioration factor described in Embodiments 1 to 2 will be described.

Fig. 8 is a schematic diagram illustrating an application of the battery management device according to the third embodiment. The battery management device estimates battery deterioration factors in accordance with the procedures of the flowcharts described in Embodiments 1 and 2. Batteries necessary for charging and discharging, such as battery cells, battery modules, battery packs, etc., are connected to various devices. Such as tester, BMS (battery management system), charger, etc. When the battery is connected to these devices, it is in any of charging operation/discharging operation/rest state. Depending on where to implement the algorithm for calculating the degradation factors, the degradation factors can be calculated on, for example, the above-mentioned device, or can be calculated on a computer connected through a network such as a cloud server. The advantage of performing calculations on a device connected to a battery is that the battery status (battery output voltage, battery output current, battery temperature, etc.) can be obtained frequently.

The deterioration factors calculated on the cloud system can also be transmitted to the computer owned by the user. The user's computer can provide this information for specific purposes such as inventory management. The degradation factors calculated on the cloud system can be stored in the database of the cloud platform operator and used for other purposes. For example, the optimization of the switching path of electric vehicles, energy management, etc.

FIG. 9 shows the battery management device 100 of the third embodiment The diagram of the composition example. In FIG. 9 , the battery management device 100 is connected to the battery 200 and receives power supply from the battery 200 , and corresponds to the tester or the like in FIG. 8 . The battery management device 100 includes: a communication unit 110 , a computing unit 120 , a sensing unit 130 , and a memory unit 140 .

The sensing unit 130 obtains a detection value V of the voltage output from the battery 200 and a detection value I of the current output from the battery 200 . Alternatively, the detected value T of the temperature of the battery 200 may be acquired separately. These detection values can be detected by the battery 200 itself and notified to the sensing unit 130 , or can be detected by the sensing unit 130 . The sensing unit 130 will be described in detail later.

The computing unit 120 estimates the deterioration factor of the battery 200 using the detection value obtained by the sensing unit 130 . The order of estimation is that described in Embodiments 1 and 2. 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, it can be transmitted to the memory of the cloud system. The storage unit 140 stores the relationship data described in Embodiments 1 and 2.

The computing unit 120 can also be configured by hardware such as circuit elements with its functions, or can be configured by a computing device such as a CPU (Central Processing Unit, central processing unit) executing software with its functions.

FIG. 10 is a diagram illustrating another configuration example of the battery management device 100 . The battery management device 100 does not have to be a device that is directly connected to the battery 200 to receive power supply, and a form that does not include the communication unit 110 and the sensing unit 130 described in FIG. 9 is shown. In FIG. 10 , the battery management device 100 obtains the voltage V, current I, and temperature T of the battery 200 from the communication unit 110 . Specifically, the sensing unit 150 included in the battery management device 100 receives the detected values, for example, via a network, and the computing unit 120 uses the detected values to calculate the deterioration factor.

FIG. 11 shows a configuration example when the sensing unit 130 is connected to the battery 200 . The sensing unit 130 can also be configured as a part of the battery management device 100 , or can be configured as another module different from the battery management device 100 . The sensing unit 130 is provided with: a voltage sensor 131 , a temperature sensor 132 , and a current sensor 133 , so as to obtain the voltage V, temperature T, and current I of the battery 200 during charging and discharging operations.

The voltage sensor 131 measures the voltage across the battery 200 (voltage output from 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 through this. The current sensor 133 is connected to one end of the battery 200 to measure the output current of the battery 200 . The temperature sensor 132 is an option, and may not necessarily be provided.

<Embodiment 4>

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

FIG. 12 is a flowchart illustrating the procedure for calculating the SOH by the calculation unit 120 . The calculation unit 120 is, for example, when the battery management device 100 is activated, When the flow chart is instructed to start, the flow chart is started at an appropriate timing such as every predetermined cycle. Each step in Fig. 12 will be described below.

(Figure 12: Step S1201)

Calculator 120 determines whether it is a rest period after charging or a rest period after discharge. If it is not a rest period now, this flow chart is ended. If it is a rest period, proceed to S1202. For example, during the rest period after discharge, the current output by the battery 200 can change from a negative value (I<0) toward zero, (b) change from a negative value to a value near zero to stabilize (|I|< Threshold value) and so on to judge.

(Figure 12: Step S1202)

The calculation unit 120 calculates ΔVa and ΔVb. ΔVa is the amount of variation in the output voltage of the battery 200 from the first counting time after the end of the rest period to the first time when the first period ta has elapsed. ΔVb is the variation in the output voltage of the battery 200 from the second starting time after the first time to the second time when the second period tb has elapsed. The calculation sequence will be described later.

(Figure 12: Step S1203)

The calculation unit 120 calculates the internal resistance Ri and SOH of the battery 200 according to the following formulas 1 and 2. The f _Ri system defines Ri as a function of ΔVa. The f _Ri system has: a parameter (c_Ri_T) that varies according to the temperature of the battery 200 , and a parameter (c_Ri_I) that varies according to the output current of the battery 200 . The fSOH _system defines SOH as a function of ΔVb. The _fSOH system has: a parameter (c_SOH_T) that varies according to the temperature of the battery 200 and a parameter (c_SOH_I) that varies according to the output current of the battery 200 . These parameters are defined by the relationship table 141 stored in the memory unit 140 . A specific example of each function and a specific example of the relationship table 141 will be described later. f _Ri and f _SOH are expressions formed based on, for example, experimental data for each lot.

(Fig. 12: Step S1203: calculation formula)

Ri=f _Ri (△Va,c_Ri_T_1,c_Ri_T_2,...,c_Ri_I_1,c_Ri_I_2,...) (1)

SOH=f _SOH (△Vb,c_SOH_T_1,c_SOH_T_2,...,c_SOH_I_1,c_SOH_I_2,...) (2)

FIG. 13 is a graph showing changes in current and voltage output by the battery 200 over time during a rest period after discharge. ΔVa in S1202 is the change in the output voltage of the battery 200 from the time when the discharge is completed or the first starting time later than that to the first time when the first period ta elapses. The inventors of the present invention have found that the voltage fluctuation due to the internal resistance of the battery 200 appears well in the output voltage immediately after the discharge is completed. That is, it can be said that the variation (ΔVa) of the output voltage during this period has a strong correlation between Ri. In the present embodiment, this fact is utilized to estimate Ri from ΔVa. The optimum values of the start time and time length of ta can be obtained from the interval from the end time of the discharge to the maximum point of the slope change rate in the voltage temporal change curve. Wherein, when specifying the aforementioned section, it may be appropriately and preferably used to form near both ends of the aforementioned section, or a region including both ends, etc., depending on the type, device, precision, etc. of the battery.

The start time of ta may not necessarily be the same as the end time of discharge, and it is better to be close to the end time of discharge. The start time of tb may not necessarily be the same as the end time of ta. In any case, ta and tb have the so-called ta<tb relationship. Regarding the magnitude of ΔVa and the magnitude of ΔVb, ΔVa may be larger, and ΔVb may be larger. Among them, ta<tb is formed in this system, but depending on the type, device, precision, etc. of the battery, there are cases where ta>tb or ta=tb, so it is sufficient to form an appropriate and better relationship.

From the results of experiments conducted by the present inventors, it has been found that Ri and SOH can be estimated with high accuracy even if the sum of ta and tb is, for example, about several seconds. Therefore, according to this embodiment, both Ri and SOH can be estimated rapidly during the idle period.

FIG. 14 is a graph showing changes in current and voltage output from the battery 200 over time during a rest period after charging. ΔVa in S1202 may be used instead of discharge, and may be the change in the output voltage of battery 200 from the time when charging is completed or the first starting time later than that to the first time when the first period ta elapses. At this time, ΔVb in S1202 is the variation in the output voltage of the battery 200 from the time when the period ta has elapsed or the second starting time after that to the second time when the second period tb has elapsed. The present inventors found that ΔVa has a correlation with Ri and ΔVb has a correlation with SOH even during the rest period after charging. Therefore, in this embodiment, ΔVa and ΔVb in S1202 can also be obtained after charging and discharging.

FIG. 15 is a diagram showing a configuration of the relationship table 141 and an example of data. The relationship table 141 is a data table defining the parameters in Equation 1 and Equation 2. c_Ri_I and c_SOH_I vary according to the output current of the battery 200 , so they are defined for each output current value. c_Ri_T and c_SOH_T vary according to the temperature of the battery 200 , so they are defined for each temperature. Since these parameters may have different characteristics between the rest period after discharge and the rest period after charge, the relationship table 141 defines each parameter for each of these periods. The relational table 141 may be constituted as a part of the relational table described in Embodiments 1 and 2, or may be constituted as other data.

If f _Ri is a linear function of ΔVa, Ri can be represented by, for example, the following Equation 3. The slope of Ri is affected by temperature, and the intercept is affected by current. At this time, c_Ri_T and c_Ri_I are each one.

Ri=c_Ri_T_1×△Va+c_Ri_I_1 (3)

If _fSOH is a linear function of ΔVb, SOH can be represented by, for example, the following Equation 4. The slope of SOH is affected by temperature, and the intercept is affected by current. At this time, there is one c_SOH_T and one c_SOH_I each.

SOH=c_SOH_T_1×△Vb+c_SOH_I_1 (4)

FIG. 16 is an example of the user interface presented by the battery management device 100 . The user interface may be presented on a display device such as a display element. The user interface prompts the calculation result obtained by the calculation unit 120 . In FIG. 16 , the temporal change of the output voltage on the logarithmic time axis is shown, and three factors including positive electrode material contact resistance/negative electrode resistance/positive electrode charge transfer resistance are illustrated as deterioration factors. In addition, the estimated battery deterioration status can also be presented state result.

<Modification of the present invention>

This invention is not limited to the above-mentioned embodiment, Various modification examples are included. For example, the above-mentioned embodiments are described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the described configurations. In addition, a part of the structure of a certain embodiment may be replaced with the structure of another embodiment, and the structure of another embodiment may be added to the structure of a certain embodiment. In addition, addition/deletion/replacement of other configurations may be performed for a part of configurations of each embodiment.

In the above embodiments, the inflection point on the logarithmic time axis was specified, but in order to specify the inflection point, it is not necessary to convert the time axis to logarithm. That is, it is sufficient if the inflection point that appears when the temporal change of the output voltage is assumed to be plotted on a logarithmic time axis can be specified in a certain order.

In the above embodiment, it has been described that the deterioration factor is estimated during the rest period after the discharge operation of the battery. However, if there is a change in the output voltage corresponding to the deterioration factor over time during the rest period after the charge operation, the same implementation as above can be performed. The deterioration factor is estimated similarly to the form. The cause of deterioration occurs during the rest period after the discharge operation, during the rest period after the charge operation, or both of them, depending on the characteristics of the battery. Therefore, depending on the characteristics of the battery, any one of these factors may be used to estimate the deterioration factor.

Claims (9)

A battery management device, which is a battery management device that manages the state of a battery, is characterized in that it includes: a sensing unit that obtains a detected value of a voltage output by the battery; a calculation unit that estimates the state of the battery, The calculation unit determines the inflection point when the voltage changes over time on the logarithmic time axis during the rest period after the battery finishes charging or discharging, and the calculation unit calculates the inflection point determined by the inflection point. For the difference of the voltage in the section of the interval of the rest period, the calculation unit obtains the relationship data describing the relationship between the difference and the deterioration factor of the battery, and the calculation unit uses the difference and refers to the relationship data , thereby inferring the deterioration factor of the aforementioned battery. The battery management device according to claim 1, wherein the calculation unit uses the inflection point to divide the rest period, thereby specifying the interval of 1 or more, and the relationship data is based on the interval and the type of the deterioration factor For each combination, the relationship between the aforementioned difference and the degree of progress of the aforementioned deterioration factor is described, and the aforementioned calculation unit uses the aforementioned difference in the aforementioned specified interval and refers to the aforementioned relationship data, thereby specifying the aforementioned degradation corresponding to the aforementioned interval The category of the factor and specifies the progress of the aforementioned deterioration factor corresponding to the aforementioned difference Spend. The battery management device according to claim 1, wherein the relational data is described for each of the temperature of the battery, the output current of the battery, or the output voltage of the battery, indicating the difference and the deterioration factor The parameters of the function of the relationship between the degree of progress, the calculation unit uses at least any one of the temperature of the battery, the output current of the battery, or the output voltage of the battery, and refers to the relationship data to obtain the above-mentioned As for the parameters, the calculation unit calculates the value of the function by using the acquired parameters and the difference, thereby calculating the degree of progress of the deterioration factor. The battery management device according to claim 1, wherein the relational data describes the materials of the components forming the battery, and the calculation unit uses the difference as the deterioration factor and refers to the relational data to estimate the materials. The battery management device according to claim 4, wherein the above-mentioned relational data describes the information specifying the above-mentioned material for each generation or model of the above-mentioned battery, and the above-mentioned computing unit estimates the generation or model of the above-mentioned battery by estimating the above-mentioned material. model. The battery management device according to claim 1, wherein the calculation unit obtains the voltage at the first starting time point after the end time point when the charging or discharging of the battery is completed, and the voltage after the first starting time point After obtaining the first difference between the voltages at the first time point in the first period, the calculation unit obtains the voltage at the second starting time point after the first time point, and the second voltage after the second starting time point after the first time point. For a second difference between the voltages at a second point in time during the period, the calculation unit acquires a relationship between the first difference and the internal resistance of the battery, and a relationship between the second difference and the deterioration of the battery. For the second relationship data of the relationship between states, the calculation unit uses the first difference and refers to the second relationship data to estimate the internal resistance. The calculation unit uses the second difference and refers to the second relationship data, from which the aforementioned deterioration state can be estimated. The battery management device according to claim 1, wherein the battery management device further includes: a user interface for presenting the deterioration factor estimated by the computing unit. The battery management device according to claim 1, wherein the calculation unit calculates the slope of the voltage on the logarithmic time axis relative to the logarithmic time as the difference. A battery management method, which is a battery management method for managing the state of a battery, characterized by comprising: a step of acquiring a detected value of a voltage output by the battery, and a step of estimating the state of the battery, wherein in the step of estimating , during the rest period after the aforementioned battery finishes charging or discharging, it is specified that the aforementioned In the step of estimating the inflection point when the voltage changes over time, the difference of the voltage in the intervals in the rest period separated by the inflection point is calculated, and in the step of estimating, Relational data describing the relationship between the difference and the battery deterioration factor is obtained, and in the step of estimating, the battery deterioration factor is estimated by using the difference and referring to the relationship data.

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