WO2024042758A1

WO2024042758A1 - Battery management device and battery management method

Info

Publication number: WO2024042758A1
Application number: PCT/JP2023/011628
Authority: WO
Inventors: 亨河野; 隼角田; 穣植田; アキラ藤本; 博也藤本; 絵里磯崎; 慧土秋月
Original assignee: 株式会社日立ハイテク
Priority date: 2022-08-22
Filing date: 2023-03-23
Publication date: 2024-02-29
Also published as: JP2024029593A

Abstract

The purpose of the present invention is to provide a technology capable of diagnosing the deterioration speed of a battery in a short time. A battery management device according to the present invention specifies a first period during an idle period and a second period after the first period, and estimates the deterioration speed of a battery dependent on the battery temperature, on the basis of a ratio between a first change portion of a voltage during the first period and a second change portion of the voltage during the second period (see fig. 5).

Description

Battery management device, battery management method

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

As a technique for diagnosing battery deterioration, for example, a technique for estimating SOH (State of Health) and internal resistance has been developed. Furthermore, techniques have been developed to shorten the time required for diagnosis. For example, there is a method of estimating the state of deterioration using the change in battery voltage over time when the battery is in a resting state.

Patent Document 1 below describes ``Easier determination of deterioration of zinc batteries.'' ``A method for determining deterioration of a zinc battery according to an embodiment includes an acquisition step of acquiring a voltage transition of a fully charged zinc battery in a resting state, and a step of acquiring a voltage transition of a fully charged zinc battery in a resting state, and determining the degree of voltage drop of the zinc battery based on the voltage transition.'' and a determination step of determining deterioration of the zinc battery based on the degree of voltage drop. ” (see summary).

JP2020-003218A

The remaining life of a battery is one of the important diagnostic items. One example of a method for diagnosing the remaining life is to estimate the rate at which the battery has deteriorated (deterioration mode) from the start of operation to the present time, and further estimate the remaining life based on the estimated deterioration rate. It would also be desirable if the time required to diagnose the remaining lifespan could be shortened as much as possible. However, in the prior art such as Patent Document 1, although a technique for diagnosing a deterioration state in a short period of time has been studied, a technique for diagnosing the remaining life in a short period of time has not been studied. Furthermore, in order to diagnose the remaining life, it is necessary to estimate the deterioration rate, for example, but a technique for estimating this in a short time has not been studied.

The present invention has been made in view of the above-mentioned problems, and aims to provide a technique that can diagnose the deterioration rate of a battery in a short time.

The battery management device according to the present invention specifies a first period in a rest period and a second period thereafter, and a first change in voltage in the first period and a second change in voltage in the second period. Estimate the rate of battery deterioration depending on the battery temperature based on the ratio between minutes.

According to the battery management device according to the present invention, the deterioration rate of a battery can be diagnosed in a short time. Other problems, configurations, effects, etc. of the present invention will become clear from the description of the embodiments below.

FIG. 1 is a schematic diagram showing a configuration example of a storage battery system. It is an equivalent circuit diagram of a storage battery. It is a graph showing an example of a change in voltage output by a battery over time during a rest period. FIG. 3 is a diagram showing storage deterioration of a battery. FIG. 3 is a diagram illustrating the relationship between battery temperature and deterioration rate. FIG. 4 is a diagram showing the relationship between each value explained in FIG. 3 and SOH. 2 is a flowchart illustrating a procedure in which the battery management device estimates a battery deterioration mode. FIG. 3 is a diagram showing cycle deterioration of a battery. FIG. 3 is a diagram illustrating the relationship between battery temperature and deterioration rate. FIG. 4 is a diagram showing the relationship between each value explained in FIG. 3 and SOH. 2 is a flowchart illustrating a procedure in which the battery management device estimates a battery deterioration mode. FIG. 3 is a configuration diagram of a battery system 1 according to a third embodiment. 3 is a diagram showing an example of operation of the battery management device 13. FIG. 7 is a diagram illustrating another operational example of the battery management device 13. FIG. This is an example of the results of a trial calculation of the economic value of batteries.

<Embodiment 1>
FIG. 1 is a schematic diagram showing a configuration example of a storage battery system. A storage battery system includes a battery system including one or more storage batteries, and a battery management device that manages the battery system. In the following, we assume that the battery is a storage battery.

The battery system includes a battery module. A battery module is made up of one or more submodules. The submodule includes a battery cell and a sensor group. The sensor group includes, for example, a voltage sensor that measures the output voltage of the battery cell, a temperature sensor that measures the temperature of the battery cell, and a current sensor that measures the output current of the battery cell. The temperature sensor can be constituted by a thermocouple, for example. The detection unit acquires measurement results from the sensor and transmits them to the battery management module (BMU). The BMU outputs measurement data describing the measurement results to the battery management device.

The battery management device includes a detection unit that acquires measurement data, a calculation unit that manages the state of the battery, a storage unit that stores data, and the like. The calculation unit estimates the state of the battery using the measurement data acquired from the BMU. For example, as explained below, the remaining life of the battery (or the rate of deterioration used to estimate the remaining life) can be estimated.

FIG. 2 is an equivalent circuit diagram of the storage battery. The equivalent circuit of a storage battery can be described using internal resistance, negative equivalent circuit, positive equivalent circuit, diffused resistance, and the like. The negative equivalent circuit and the positive equivalent circuit can be described as RC equivalent circuits having time constants. Generally, the time constant of the negative electrode is smaller than that of the positive electrode. In other words, the negative electrode responds faster. The diffused resistance component occurs at a later time than the positive electrode.

FIG. 3 is a graph showing an example of a change over time in the voltage output by the battery during the rest period. The upper part of FIG. 3 shows the change in battery voltage over time during the rest period after the discharging operation. The lower part of FIG. 3 shows the change in battery voltage over time during the rest period after the charging operation. ΔVa is a change over time mainly caused by the internal resistance and the response of the negative electrode, which responds relatively quickly. ΔVb is a change over time mainly caused by the response of the positive electrode and the diffused resistance, which respond relatively slowly. A period in which ΔVa occurs is defined as a first period (time length is Δt1), and a period in which ΔVb occurs is defined as a second period (time length is Δt2).

The deterioration mode (deterioration speed) of the battery may affect the response speed of the battery components. As a result, ΔVa/Δt1, ΔVb/Δt2, the ratio between ΔVa and ΔVb, etc. in FIG. 3 change. That is, since the battery deterioration mode and these values have a correlation, it is considered that the battery deterioration mode can be estimated based on these values. The battery management device according to the present invention utilizes this fact to estimate the battery deterioration mode. The specific method will be explained below.

FIG. 4 is a diagram showing storage deterioration of a battery. Deterioration continues even when batteries are stored without being used. As a result of verification in the present invention, it was found that when a battery is stored at a certain SOC (State of Charge) and a certain temperature, the battery deteriorates depending on the SOC and temperature.

The left side of FIG. 4 shows the progress of deterioration when a battery with an SOC of C1% (for example, less than 80%) is stored at battery temperatures T1, T2, and T3. The battery temperatures are, for example, T1=5°C, T2=25°C, and T3=45°C. At any temperature, deterioration progresses as the number of days of storage increases, and the higher the temperature, the faster the deterioration rate.

The right side of FIG. 4 shows the progress of deterioration when a battery with an SOC of C2% (for example, 80% or higher) is stored at battery temperatures T1, T2, and T3. Compared to the left side of FIG. 4, it can be seen that the deterioration rate is particularly fast at temperature T3. That is, it is thought that the deterioration rate (deterioration mode) is correlated with the battery temperature and also with the SOC.

FIG. 5 is a diagram illustrating the relationship between battery temperature and deterioration rate. As shown in FIG. 4, as the battery temperature increases, the deterioration rate (the downward slope to the right in FIG. 4, that is, the rate of decrease in SOH with respect to the number of days elapsed) tends to increase. This slope is relatively small (slope A) when stored with a small SOC, but relatively large (slope B) when stored with a large SOC. This can also be seen from the large slope of the temperature T3 on the right side of FIG.

According to FIG. 5, it is determined whether the deterioration rate is slope A or slope B, with a certain temperature as the boundary. Further, the deterioration rate differs depending on whether the SOC is relatively small (eg, C1%) or relatively large (eg, C2%). In other words, it can be seen that it is possible to estimate at which deterioration rate the deterioration occurred based on a certain temperature threshold value and SOC threshold value.

FIG. 6 is a diagram showing the relationship between each value explained in FIG. 3 and SOH. For both ΔVa and ΔVb, the time change rate (dVdt1=ΔVa/Δt1, dVdt2=ΔVb/Δt2) decreases as the SOH decreases. In a deterioration mode in which the deterioration rate is high (for example, slope B in FIG. 5, which corresponds to the case where the SOC is high and the battery temperature is also high), it is considered that the SOH decreases more greatly even at the same time change rate. That is, it is considered that the graph passes through the area surrounded by the dotted line in the middle part of FIG.

Consider the ratio between dVdt1 and dVdt2. When the deterioration rate is relatively slow, it is assumed that dVdt1 and dVdt2 are as shown by the solid lines in FIG. 6, respectively. If the deterioration rate is faster than this, the graph of dVdt2 is considered to pass within the dotted line region in the middle of FIG. At this time, when dVdt1 and dVdt2 corresponding to the same SOH value are obtained, dVdt2 becomes a value smaller than the solid line in FIG. 6. In other words, when comparing cases where the deterioration rate is fast and slow, the value of dVdt2 corresponding to the same value of dVdt1 is smaller when the deterioration rate is faster. This corresponds to the graph shifting toward the left in the lower part of FIG.

Then, when the ratio of dVdt1 to dVdt2 is plotted as shown in the lower part of FIG. 6, if it is above the upper limit threshold of the graph, it can be estimated that the deterioration has progressed in a mode where the deterioration rate is fast. On the other hand, if the plot is below the upper threshold, it can be estimated that the deterioration has progressed in a mode where the deterioration rate is slow. In this embodiment, the battery deterioration mode is estimated based on this principle. If it is below the lower limit threshold, it may be estimated that the deterioration rate is even slower.

FIG. 7 is a flowchart illustrating the procedure by which the battery management device estimates the battery deterioration mode. This flowchart can be executed by a calculation unit included in the battery management device. This flowchart is for estimating in what kind of deterioration mode a battery in a stored state has deteriorated, based on the principle explained above. Each step in FIG. 7 will be explained below.

The calculation unit obtains ΔVa, Δt1, ΔVb, and Δt2 described in FIG. 3 from, for example, the BMU. The calculation unit calculates the rate of change in battery voltage over time (dVdt1=ΔVa/Δt1, dVdt2=ΔVb/Δt2). The calculation unit calculates the ratio Ratio of dVdt1 to dVdt2. If Ratio exceeds the threshold value, the battery deterioration rate slope is estimated to be B (a deterioration mode in which the deterioration rate is relatively fast). If Ratio is less than or equal to the threshold value, the battery deterioration rate slope is estimated to be A (a deterioration mode in which the deterioration rate is relatively slow).

Based on the estimated deterioration mode, the calculation unit estimates the temperature and SOC at which the battery was stored. First, based on the estimated deterioration mode, it is possible to estimate whether the slope of the deterioration rate with respect to temperature change is, for example, slope A or slope B in FIG. 5 (in other words, whether the SOC is C1 or C2). This corresponds to identifying whether the battery has deteriorated in the left or right deterioration mode shown in FIG.

The calculation unit estimates the activation energy Ea of the battery. By estimating the deterioration mode using the above procedure, it is possible to estimate whether the battery has deteriorated in the left or right deterioration mode in FIG. Thereby, the relationship between SOH/number of elapsed days (or number of cycles)/temperature as shown in FIG. 4 can be estimated. By substituting this temperature into the Arrhenius equation, for example, the activation energy can be calculated. Activation energy and deterioration mode generally have a 1:1 correspondence, so the relationship between a deterioration mode and the activation energy for that deterioration mode is described in advance in a data table, etc., and it is possible to correspond to the estimated deterioration mode. The activation energy for the target may be obtained from the data table.

The calculation unit acquires the number of times the battery has been charged or discharged from the BMU. Alternatively, the number of times of charging and discharging is estimated by obtaining the amount of decrease in full charge capacity due to one charge or discharge from the BMU and comparing this with the current full charge capacity (i.e., current SOH). . The calculation unit further estimates the SOH using any known method. For example, the SOH can be estimated by referring to data describing any one of the correspondence between dVdt1 and SOH, the correspondence between dVdt2 and SOH, a combination thereof, and the like.

The calculation unit uses the estimated SOH and the number of times of charging and discharging to estimate the temperature T1 at which the battery has been kept in the storage state. For example, by applying the current SOH and the number of charge/discharge cycles (or converted to the number of elapsed days) to the relationship shown in FIG. 4, it is possible to estimate the temperature at which the battery has been placed. If there is no location where the data points in FIG. 4 match the acquired SOH/days, the data points in FIG. 4 may be supplemented.

The calculation unit calculates the deterioration acceleration of the battery by applying the estimated temperature T1 and activation energy to the Arrhenius equation. The reference temperature T2 is, for example, 298K. Through the above procedure, the battery management device can estimate the deterioration mode and deterioration acceleration of the battery. The calculation unit outputs the estimation result in an appropriate format.

<Embodiment 1: Summary>
The battery management device according to the present embodiment estimates the deterioration rate depending on the battery temperature based on the first change and the second change in the battery voltage during the rest period. Since the first change amount and the second change amount appear in a relatively short time after the charging/discharging operation ends, the deterioration rate can be estimated within a short time.

<Embodiment 2>
FIG. 8 is a diagram showing cycle deterioration of a battery. T1 to T3 are the same as in FIG. In the first embodiment, storage deterioration of the battery has been described, but the battery also deteriorates with each charge/discharge cycle. As a general rule, the higher the temperature, the faster the rate of deterioration (the amount of decrease in SOH per charge/discharge cycle). However, depending on the characteristics of the battery, if the battery is not operated at a C rate below the upper limit at low temperatures, the rate of deterioration may be faster than normal. The graph of temperature T1 in FIG. 8 represents this. In Embodiment 2 of the present invention, a method for estimating the deterioration rate in such a case will be described. The configurations of the battery system and battery management device are the same as in the first embodiment.

FIG. 9 is a diagram illustrating the relationship between battery temperature and deterioration rate. The upper part of FIG. 9 shows the upper limit of the C rate that the battery should comply with. In this battery example, an upper limit C rate that must be observed during charging and discharging operations of the battery is defined for each battery temperature. Similarly to FIG. 5, the lower part of FIG. 9 shows the relationship between battery temperature and deterioration rate. However, unlike FIGS. 4-5, the deterioration rate is the rate of decrease in SOH with respect to the increase in the number of cycles.

Similarly to FIG. 5, when the SOC is relatively small (eg, C1%), the slope of the deterioration rate with respect to temperature change is C. If the battery temperature is below 25° C., the slope increases to D2 if the C rate upper limit is not observed. If the deviation from the C rate upper limit becomes even greater, the slope increases to D1.

FIG. 10 is a diagram showing the relationship between each value explained in FIG. 3 and SOH. Similar to FIG. 6, regions where the slope of the deterioration rate is large are indicated by dotted lines. For example, as explained in FIG. 9, when the battery is operated in a low temperature environment of 25° C. or lower, the deterioration rate increases if the C rate upper limit is not observed. This is shown by the dotted line area in FIG. In the lower part of FIG. 10, the region where dVdt2/dVdt1 is larger than the threshold value includes regions corresponding to each of the two deterioration modes (inclinations D1 and D2) explained in FIG.

In the lower part of FIG. 10, the same upper limit threshold (and lower limit threshold, if necessary) as in the lower part of FIG. 6 was set in a coordinate space in which the vertical axis is dVdt2/dVdt1 and the horizontal axis is dVdt2. Alternatively, the vertical axis may be set to dVdt1 as in the lower part of FIG. In other words, when dVdt2/dVdt1 exceeds the upper limit threshold, as long as it is possible to clearly distinguish which deterioration mode (D1 or D2) the vertical axis corresponds to, the vertical axis may be in any format. It's just a difference.

FIG. 11 is a flowchart illustrating the procedure by which the battery management device estimates the battery deterioration mode. In addition to the flowchart described in Embodiment 1, a step is added to select whether the slope of the deterioration rate when Ratio exceeds the threshold is D1 or D2 (the slope of the deterioration rate explained in FIG. 9). There is. When Ratio exceeds the threshold, the calculation unit determines whether the deterioration rate is D1 or D2 according to the distance between Ratio and the threshold. For example, if the distance is relatively large, it is set as D1, and if it is relatively small, it is set as D2. The rest is the same as in the first embodiment.

<Embodiment 2: Summary>
The battery management device according to the present embodiment estimates a deterioration mode based on the degree of deviation between dVdt2/dVdt1 and a threshold value for a battery whose deterioration rate increases if the C rate upper limit is not observed in a low-temperature environment. As a result, the deterioration rate of a battery having such deterioration characteristics in a low-temperature environment can be estimated within a short time as in the first embodiment.

<Embodiment 3>
FIG. 12 is a configuration diagram of a battery system 1 according to Embodiment 3 of the present invention. The battery system 1, battery controller (BMU) 12, and battery management device 13 are those illustrated in FIG. The battery system 1 includes a host controller 11, a battery controller (BMU) 12, and a battery management device 13. The host controller 11 outputs operation instructions for the battery via the battery controller 12. The battery controller 12 controls the battery modules according to the instructions. The battery management device 13 includes a detection unit 131 that acquires measurement data from the battery controller 12, a calculation unit 132 that diagnoses the battery using the methods described in the first and second embodiments, a storage unit 133 that stores data used by the calculation unit 132, Equipped with

FIG. 13 is a diagram showing an example of operation of the battery management device 13. The detection unit 131 acquires measured values such as battery voltage, battery temperature, battery current, C rate, and SOC of each battery module (or battery cell) or their history from the BMU, and records them in the storage unit 133. Using the data, the calculation unit 132 estimates the deterioration mode and deterioration acceleration of the battery using the methods described in the first and second embodiments. Thereby, it is possible to monitor whether the deterioration mode of each battery can be maintained appropriately.

For example, when transmitting the power generated by a power generation system including a battery system over a power company's power transmission network, a power transmission plan is created in advance and sent to the power company the day before the power transmission, and immediately before power transmission starts on the day the power transmission is carried out. It is conceivable to diagnose battery capacity within a short period of time. In such a case, the diagnostic method according to the present invention is useful in that the diagnosis can be completed in a short time. Furthermore, by accumulating the battery temperature history in the storage unit 133, there is no need to estimate the experienced temperature T1 in FIG. 7 or FIG. 11 (it is sufficient to use the average value of the temperature history as T1). Useful.

FIG. 14 is a diagram showing another example of operation of the battery management device 13. The battery management device 13 is connected to the charger via a cloud system or the like. A charger is a device that charges a battery mounted on a vehicle. The detection unit 131 acquires measurement data such as battery voltage and battery temperature of a battery mounted on the vehicle via a charger (or via a measuring device connected to the vehicle). The calculation unit 132 diagnoses the battery's deterioration mode, deterioration acceleration, remaining life, etc. using the measured data. This makes it possible to estimate the economic value of the vehicle or the battery installed in the vehicle.

FIG. 15 is an example of the results of a trial calculation of the economic value of a battery. The calculation unit 132 calculates the SOH/deterioration acceleration/economic value ranking based on these for each battery according to the procedure described in the above embodiments, and outputs the results. The rank is, for example, a comprehensive evaluation based on a combination of SOH and deterioration acceleration. The output format may be data that describes these, or may be output via an output medium such as a display.

For batteries with a low evaluation (or with a high rate of deterioration), the calculation unit 132 imposes restrictions on the charging current and the state of charge after the charging operation, so as not to accelerate the deterioration even if charging is performed. good. It is desirable to diagnose the deterioration rate and the like during a period when no charging/discharging operation is performed. The same applies to any of FIGS. 13 to 14.

<About 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 to explain the present invention in an easy-to-understand manner, and the present invention is not necessarily limited to having all the configurations described. Furthermore, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace some of the configurations of each embodiment with other configurations.

In the above embodiments, it has been explained that the deterioration rate of the battery is estimated using the ratio between dVdt1 (ΔVa) and dVdt2 (ΔVb). In addition to this, a similar rate of change over time after ΔVb may be further used to perform a more detailed diagnosis.

In the above embodiments, the start time of ΔVb is after the start time of ΔVa, and the end time of ΔVb is after the end time of ΔVa. As long as this relationship is maintained, for example, Δt1 (first period) and Δt2 (second period) may partially overlap.

In the embodiments described above, the detection unit 131 and the calculation unit 132 can be configured by hardware such as a circuit device implementing the function, or software implementing the function can be configured by a calculation unit such as a CPU (Central Processing Unit). It can also be configured by the device executing it.

13: Battery management device 131: Detection section 132: Arithmetic section 133: Storage section

Claims

A battery management device that manages battery status,
a detection unit that obtains a detected value of the voltage output by the battery;
a calculation unit that estimates the state of the battery;
Equipped with
The calculation unit includes a first period in a rest period after the battery finishes a charging operation or a discharging operation, and a first period in the rest period that starts after the start time of the first period and from the end time of the first period. and a second period that ends after
The calculation unit specifies a first change in the voltage in the first period and a second change in the voltage in the second period,
The battery management device is characterized in that the calculation unit estimates a deterioration rate of the battery, which is dependent on the temperature of the battery, based on a ratio between the first variation and the second variation.
The battery is
a first component that causes a change in the voltage according to a first time constant;
a second component that causes a change in the voltage according to a second time constant that is greater than the first time constant;
Equipped with
The calculation unit uses, as the first period, a period in which the voltage changes according to the first time constant,
The battery management device according to claim 1, wherein the arithmetic unit uses a period in which the voltage changes according to the second time constant as the second period.
The battery has a first degradation mode in which the battery degrades at a first degradation rate when the temperature of the battery is below a temperature threshold or the state of charge of the battery is below a state of charge threshold;
The battery has a deterioration mode in which the battery deteriorates at a deterioration rate greater than the first deterioration rate when the temperature of the battery is equal to or higher than the temperature threshold and the state of charge of the battery is equal to or higher than the state of charge threshold;
The calculation unit estimates, based on the ratio, whether the battery has deteriorated in the first deterioration mode or in a deterioration mode with a higher deterioration rate than the first deterioration mode. Item 1. The battery management device according to item 1.
The battery has a characteristic of deteriorating at the first deterioration rate or a deterioration rate greater than the first deterioration rate in the storage state, depending on the temperature of the battery in the storage state and the state of charge of the battery in the storage state. has
The battery estimates, based on the ratio, whether the battery deteriorated in the first deterioration mode or in a deterioration mode with a faster deterioration rate than the first deterioration mode in a past storage state. The battery management device according to claim 3, characterized in that:
The calculation unit estimates the activation energy of the battery in a past storage state based on the ratio,
The calculation unit estimates a temperature of the battery based on a state of deterioration of the battery,
The battery management device according to claim 4, wherein the calculation unit estimates the deterioration acceleration of the battery using the estimated activation energy and the estimated temperature.
The calculation unit estimates a state of deterioration of the battery,
The calculation unit acquires the number of times the battery has performed a charging operation or a discharging operation, or calculates the estimated state of deterioration and the amount of capacity reduction of the battery due to one charging operation or one discharging operation. estimate the number of times using
The battery management device according to claim 5, wherein the calculation unit estimates the temperature of the battery using the number of times and the estimated state of deterioration.
The calculation unit obtains a relationship among the deterioration state, the number of times or elapsed time from the start of operation of the battery, and the temperature of the battery,
The battery management device according to claim 6, wherein the calculation unit estimates the temperature of the battery by applying the estimated deterioration state and the number of times or the elapsed time to the relationship.
The calculation unit estimates the deterioration state using a correspondence relationship between the first change amount and the deterioration state, or a correspondence relationship between the second change amount and the deterioration state. The battery management device according to claim 6.
The battery has a third deterioration mode in which it deteriorates at a third deterioration rate above a reference temperature,
The battery has a fourth deterioration mode in which the battery deteriorates at a fourth deterioration rate higher than the third deterioration rate when a charging operation or a discharging operation is performed at a C rate equal to or higher than the C rate threshold below the reference temperature. ,
The battery management device according to claim 1, wherein the calculation unit estimates which of the third deterioration mode and the fourth deterioration mode the battery has deteriorated in based on the ratio.
The calculation unit calculates a distance between the ratio and a threshold value on a two-dimensional coordinate interval of the ratio and the second change,
The battery management device according to claim 9, wherein the calculation unit estimates the magnitude of the deterioration rate in the fourth deterioration mode according to the magnitude of the distance.
The battery management device according to claim 1,
a storage unit that stores data describing a history of the temperature of the battery and a history of the state of charge of the battery;
Equipped with
The battery system, wherein the calculation unit estimates the deterioration acceleration of the battery using the temperature history described by the data.
The battery management device according to claim 1,
a charger for charging the battery;
Equipped with
The calculation unit controls the charging current from the charger to the battery or the battery after being charged by the charger so as to suppress deterioration of the battery charged by the charger according to the estimated deterioration rate. A battery system characterized by controlling at least one of the charging states of the battery.
The battery system according to claim 12, wherein the calculation unit estimates the deterioration rate of the battery during a period when the charger does not perform a charging operation.
The battery management device according to claim 5,
a storage unit that stores data describing the deterioration state of the battery and the deterioration acceleration of the battery;
Equipped with
The battery system, wherein the calculation unit classifies the performance of the battery according to the estimated deterioration state and the estimated deterioration acceleration, and records the result in the data.
A battery management method for managing battery status, the method comprising:
obtaining a detected value of the voltage output by the battery;
estimating the state of the battery;
has
In the step of estimating, a first period in a rest period after the battery finishes a charging operation or a discharging operation, and a first period in the rest period that starts after the start time of the first period and the end of the first period. a second period that ends after the time;
In the estimating step, specifying a first change in the voltage in the first period and a second change in the voltage in the second period,
Battery management characterized in that, in the estimating step, a deterioration rate of the battery that depends on the temperature of the battery is estimated based on a ratio between the first change amount and the second change amount. Method.