TW202321724A - Battery management device, battery management method, and battery management program - Google Patents

Abstract

The objective of the present invention is to provide a battery management device capable of acquiring an accurate SOC of a battery without relying only on a SOC acquired by a BMU. A battery management device according to the present invention estimates the SOC by employing an amount of fluctuation of a battery voltage in a first charging operation or a first discharging operation, and an amount of fluctuation of the battery voltage in a second charging operation or a second discharging operation, and referring to data describing a relationship between the amounts of fluctuation and the SOC.

Description

Battery management device, battery management method, battery management program

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

The output voltage (cell voltage) of a lithium-ion battery unit is generally measured or obtained by a battery management unit (BMU) controlling the battery unit (or a battery unit connected to a plurality of battery units). The BMU uses the measured value to calculate the state of charge (State Of Charge: SOC) of the battery cell. The BMU transmits the calculation result to the host device through, for example, CAN (Control Area Network, Controller Area Network) communication.

As the scene where the storage battery is used involves various aspects, the need to correctly estimate the SOC increases. When transporting, for example, lithium metal batteries or lithium ion batteries, there are cases where the SOC relative to the rated capacity is calculated to be below a predetermined ratio (eg: 30% or less of the rated capacity). Alternatively, when the battery is connected to the power system from the customer side, it is necessary to accurately grasp the SOC so that the battery can be driven according to the operation schedule.

The following patent document 1 is based on the subject of "estimating SOC and SOH with high accuracy considering not only the process value of the battery but also the mutual correlation between SOC and SOH", and discloses that "in the battery controller 6BC, BCIA9 is equipped with: measuring battery The internal resistance measurement part 96 of the 25°C conversion value R25 of the internal resistance of 5, and the open voltage measurement part 97 of the 25°C conversion value OCV25 of the open voltage. The CPU 8 is equipped with a first memory indicating the relationship between OCV25, SOH and SOC. Equation, and the equation storage unit 86 of the second equation representing the relationship between R25, SOH, and SOC; and the solution of applying the measurement results of the aforementioned R25 and OCV25 to the aforementioned equations to obtain SOH and SOC as the solution of the simultaneous equations thereof Section 87" and other technologies (refer to the abstract). [Prior Art Literature] [Patent Document]

[Patent Document 1] Japanese Patent Laid-Open No. 2017-129401

(Problem to be solved by the invention)

The host device executes various actions based on the SOC obtained from the BMU. The principle is the same in the case of transporting the above-mentioned lithium ion battery or the like or the storage battery on the customer side, and each application is usually realized based on the SOC obtained by the BMU. However, the SOC acquired by the BMU may be notified with a certain degree of margin. For example, when the actual SOC is 80%, the BMU may report that the SOC is 70% to the host device. An application program executed by a host device (for example: remaining capacity display in an electric vehicle) may additionally display the SOC with a margin. As shown above, it is known from experience that the SOC at the time identified by the user is not necessarily consistent with the SOC notified by the BMU. In addition, the SOC notified by the BMU is not necessarily consistent with the actual SOC.

If the battery is being discharged (the same is true for charging, the same applies hereinafter) and the output voltage from the battery is measured, large noise may be superimposed on the measurement result. The BMU performs noise removal processing on the measurement result, and notifies the result to the host device. With this noise removal, there is a possibility that the measurement result reported by the BMU to the host device also deviates from the actual SOC.

The present invention was made in view of the above-mentioned problems, and an object thereof is to provide a battery management device capable of obtaining a correct SOC of a battery without relying only on the SOC obtained by a BMU. (technical means to solve the problem)

The battery management device of the present invention uses the variation of the battery voltage in the first charging operation or the first discharging operation, and the variation of the battery voltage in the second charging operation or the second discharging operation, and these are described by reference SOC can be estimated by changing the data of the relationship between credits and SOC. (Effect of Invention)

With the battery management device of the present invention, the correct SOC of the battery can be obtained without relying only on the SOC obtained by the BMU.

＜Embodiment 1＞

FIG. 1 is a schematic diagram showing how the BMU acquires the SOC of the battery cell. The BMU is connected to one or more battery cells, calculates the SOC using the output voltage or output current of the battery cells, and reports the result to the host device. The host device can visually display the SOC on, for example, the screen interface in the lower part of FIG. 1 . If the SOC is close to being fully charged, the battery icon (icon) is displayed in a fully charged state. Alternatively, the numerical value of the SOC itself may be presented.

FIG. 2 is an example of the waveform of the battery voltage measured or obtained by the BMU during the battery discharge operation. A certain amount of noise is superimposed on the measured value of the battery voltage (output voltage from the battery). Especially during the discharge operation, it is empirically known that there is a large overlapping noise. Noise is relatively small during the rest period (period in which neither discharge nor charge is performed) following the discharge operation, but there is still a certain amount of noise superimposed on the measurement results. The left panel of Figure 2 shows a voltage waveform with noise superimposed on it. Therefore, the BMU obtains the voltage waveform shown in the right figure of Figure 2 by implementing noise removal processing, and reports this to the host device, or estimates the SOC based on it. The same applies to the charging operation.

As shown in Figure 2, if the BMU reports the measurement result to the host device after performing noise removal on the battery voltage, the measurement result will be offset by the noise removal process, and the host device cannot Possibility to obtain accurate measurement results. For example, as a result of measuring the cell voltage during the discharge operation, the battery voltage monotonically decreases as the discharge progresses, but the battery voltage waveform output by the BMU quickly becomes stable. Therefore, it is presumed that there is an offset between the actual battery voltage and the measured value obtained by the BMU. During the rest period, although it is not as large as during the discharge operation, it is presumed that the measurement results obtained by the BMU are similarly superimposed with an offset.

Fig. 3 is a configuration diagram of the battery management device 100 according to Embodiment 1 of the present invention. The battery management device 100 is a device that manages the state of the battery 200 . The battery management device 100 includes: a communication unit 110 , a calculation unit 120 , a detection unit 130 , and a memory unit 140 . The detection unit 130 obtains the output voltage, output current, temperature, etc. of the battery 200 . These are not necessarily measured by the detection unit 130 itself, and the measurement results may be obtained by, for example, the BMU. Calculator 120 estimates the SOC of battery 200 using these measurement results. The communication unit 110 transmits the estimation result to an external device. The storage unit 140 is a device for storing data used by the calculation unit 120 .

FIG. 4 shows an example of the discharge operation when the battery management device 100 estimates the SOC of the battery 200 . When the battery 200 is estimated by the battery management device 100 to estimate the SOC of the battery 200 , as shown in FIG. 4 , two discharge operations and a subsequent rest period are performed respectively. These actions can be controlled by the battery management device 100 or by other control devices. That is, it is sufficient if the temporal variation of the battery voltage accompanying these operations can be obtained.

Calculation unit 120 grasps the SOH (State Of Health: State of Deterioration) of battery 200 in advance when estimation of the SOC of battery 200 is started. As a method for obtaining SOH, any known technique can be used, and an example thereof will be described later. The calculation unit 120 multiplies the SOH by the rated capacity [Ah] of the battery 200 to calculate the full charge capacity [Ah] of the battery 200 at that point in time. The full charge capacity can be regarded as SOC=100% at this point in time.

The computing unit 120 acquires the battery voltage V1 at the time when the battery 200 starts the first discharge operation (first discharge operation). The calculation unit 120 obtains the time length t1 during which the battery 200 has performed the first discharge operation, and calculates the discharge amount by multiplying the discharge current by t1. The calculation unit 120 can obtain the SOC that changes according to the first discharge operation by using the ratio of the discharge amount to the full charge capacity.

The computing unit 120 acquires the battery voltage V2 during the rest period (first rest period) after the first discharge operation. The computing unit 120 acquires, as V2 , the battery voltage at a time when the temporal fluctuation of the battery voltage becomes stable during the first rest period. The time from the start of the rest period until the battery voltage stabilizes is assumed to be several seconds long, and it is not necessary to use a voltage that takes tens of minutes to stabilize like the open circuit voltage as V2.

The calculation unit 120 calculates the voltage change from V1 to V2 (ΔV12=V1-V2). Thereby, the computing unit 120 can obtain the relationship between the amount of change in SOC accompanying the first discharge operation and the amount of change in battery voltage associated with the first discharge operation.

The calculation unit 120 obtains the time length t2 during which the battery 200 performs the second discharge operation (second discharge operation), and calculates the discharge amount by multiplying the discharge current by t2. The calculation unit 120 can obtain the SOC that changes according to the second discharge operation by using the ratio of the discharge amount to the full charge capacity.

The computing unit 120 acquires the battery voltage V3 during the rest period (second rest period) after the second discharge operation. The calculation unit 120 acquires, as V3, the battery voltage at a time when the temporal fluctuation of the battery voltage becomes stable during the second rest period, as in V2. The length of time from the start of the first rest period to V2 may be the same as or different from the length of time from the start of the second rest period to V3.

The calculation unit 120 calculates the voltage change from V2 to V3 (ΔV23=V2-V3). Thereby, the computing unit 120 can obtain the relationship between the amount of change in SOC accompanying the second discharging operation and the amount of change in battery voltage accompanying the second discharging operation.

FIG. 5 is a graph showing the relationship between the battery voltage and the SOC at the point in time when the temporal variation of the battery voltage becomes stable after the start of the rest period. The data shown in FIG. 5 can be obtained, for example, through experiments in advance. By differentiating the relationship shown in this data (obtaining the change of battery voltage with respect to the change of SOC), the data curve shown in Fig. 6 below can be obtained.

FIG. 6 is a diagram showing an example of data used for calculating the SOC of the battery 200 by the computing unit 120 and an estimation procedure of the SOC using the data. This document describes the relationship between the variation of the battery voltage (for example, ΔV12, ΔV23) accompanying the discharge operation illustrated in FIG. 4 and the SOC. This data is created in advance and stored in the memory unit 140 before estimating the SOC.

The computing unit 120 identifies data points corresponding to voltage fluctuations (ΔV12 and ΔV23 ) in each of the two discharge operations described in FIG. 4 from the data in FIG. 6 . The two data points thus obtained correspond to the SOC at the point in time when each discharge operation is completed. However, there may be a plurality of SOC candidates corresponding to each voltage fluctuation. In the data example of FIG. 6 , there are two SOC candidates corresponding to ΔV12, and four SOC candidates corresponding to ΔV23.

Therefore, the computing unit 120 separately specifies one corresponding to the discharge amount in the second discharge operation among the SOC candidates. For example, if the discharge amount in the second discharge operation corresponds to 1% of SOC, a SOC candidate whose difference between the SOC corresponding to ΔV12 and the SOC corresponding to ΔV23 is 1% is specified. The candidate SOC thus specified can be estimated to represent the true SOC of the battery 200 . In the data example in FIG. 6 , the data point near SOC=24% corresponds to this. Therefore, the computing unit 120 can estimate that the SOC of the battery 200 is about 24%.

The computing unit 120 can also more easily specify the one corresponding to the difference VR between ΔV12 and ΔV23 among the SOC candidates. VR corresponds to the discharge amount in the second discharge operation. In the data example of FIG. 6 , similarly, the data points near SOC=24% correspond to this. At this time, the calculation unit 120 does not need to calculate the discharge amount (I×t1, I×t2, etc.) associated with the discharge operation, and it is sufficient to specify data points corresponding to ΔV12, ΔV23, and VR on the data shown in FIG. 6 .

<Embodiment 1: Conclusion> The battery management device 100 of the first embodiment acquires V2 during the first rest period after the first discharge period, and calculates ΔV12, acquires V3 during the second rest period after the second discharge period, calculates ΔV23, and uses these Referring to the data in FIG. 6 , the SOC of the battery 200 can be estimated. By using ΔV12 or ΔV23 as the difference instead of V1 to V3 itself, even when a shift in the measurement process of the BMU is superimposed on each of V1 to V3, the influence can be canceled to some extent. In addition, it is not necessary to rely on the SOC measured by the BMU, and the SOC can be accurately obtained from the measurement result that mitigates the influence of the offset.

The relational data (data illustrated in FIG. 6 ) used when the battery management device 100 of the first embodiment estimates the SOC describes the relationship between the change in the SOC accompanying the charging and discharging operation and the change in the battery voltage at that time, and calculates The unit 120 specifies the data points corresponding to ΔV12 and ΔV23 as SOC candidates, and specifies the one corresponding to the charging and discharging amount from among the SOC candidates, thereby estimating the SOC. Thereby, even when there are a plurality of SOC candidates, the SOC corresponding to the charge and discharge amount can be accurately specified.

The relational data (data illustrated in FIG. 6 ) used when the battery management device 100 of the first embodiment estimates the SOC describes the relationship between the change in the SOC accompanying the charging and discharging operation and the change in the battery voltage at that time, and calculates The unit 120 specifies the data points corresponding to ΔV12 and ΔV23 as SOC candidates, and specifies the one corresponding to the variation (VR) of the battery voltage caused by the second charging operation or the second discharging operation from among the SOC candidates, thereby Estimated SOC. Thereby, even if the charge and discharge amount itself is not calculated, the SOC corresponding to the charge and discharge amount can be accurately specified by the variation of the battery voltage accompanying the charge and discharge operation.

In the first embodiment, an example is described in which the battery voltage is obtained during the rest period after the discharge operation, but the battery voltage can also be obtained during the rest period after the charge operation, and the SOC can be estimated by the same method. The same applies to the subsequent embodiments. For example, at the start of charging, it is sufficient to set the remaining capacity of the battery 200 to 0, and obtain the variation of the battery voltage corresponding to each of the two charging operations. As for the rest period after the charging operation, it is sufficient to measure the battery voltage when a long time has elapsed for about several seconds in which the battery voltage becomes stable.

＜Embodiment 2＞ In the first embodiment, the procedure for estimating the SOC more accurately is described considering that the battery voltage obtained by the BMU is not necessarily accurate. However, if the history of the battery voltage acquired by the BMU is accumulated to a certain extent, it is considered possible to estimate the correspondence between the battery voltage acquired by the BMU and the correct SOC. Therefore, in Embodiment 2 of the present invention, an operation example of learning the correspondence relationship between the battery voltage obtained by the BMU and the correct SOC and using this to estimate the SOC will be described. The configuration of the battery management device 100 is the same as that of the first embodiment, so the following will mainly describe matters related to learning.

FIG. 7 is a schematic diagram illustrating a procedure for the calculation unit 120 to estimate the SOC using the battery voltage obtained by the BMU. Calculator 120 estimates the SOC of battery 200 using battery voltages V1 to V3 in accordance with the procedure described in Embodiment 1. FIG. V1 to V3 used at this time are those obtained by, for example, BMU. As mentioned above, the V1-V3 may deviate from the true value, but the calculation unit 120 directly uses the V1-V3 acquired by the BMU to estimate the SOC.

The calculation unit 120 stores the correspondence relationship between the estimation result of the SOC and the sets (sets) of V1 to V3 used for the estimation in the storage unit 140 . The computing unit 120 estimates the SOC each time, that is, stores the same correspondence relationship in the memory unit 140 . By accumulating the correspondence as described above, the computing unit 120 can use the correspondence to estimate the SOC when acquiring new V1 to V3.

As a method of estimating the SOC using V1 to V3 by the calculation unit 120, for example, the following is considered: (a) learning the correspondence between V1 to V3 and the estimation result of SOC using the appropriate machine learning method relationship, put new V1~V3 into the learning model obtained as a result, thereby obtain the SOC estimation result as the output of the learner; (b) plot V1~V3 and the SOC estimation result using this, and calculate the most approximate The equations for these correspondences. By substituting new V1-V3 into this equation, the SOC estimation result is obtained.

In the method of the second embodiment, it is necessary to first accumulate the estimation results to a certain extent according to the method of the first embodiment, but after confirming the correspondence between V1-V3 and SOC, the SOC can be obtained immediately from the measured values of V1-V3. point is extremely useful.

＜Embodiment 3＞ FIG. 8 is a schematic diagram illustrating the procedure for estimating the SOC by the battery management device 100 according to Embodiment 3 of the present invention. In the second embodiment, the relationship between V1 to V3 acquired by the BMU and the SOC is learned. In Embodiment 3, instead of this, an example of learning the correspondence relationship between the SOC acquired by the BMU and the SOC estimated by the battery management device 100 will be described. The configuration of the battery management device 100 is the same as that of the first embodiment, so the following will mainly describe matters related to learning.

The BMU uses battery voltage or battery current to calculate SOC. The computing unit 120 acquires the SOC. The calculation unit 120 is different from this, and estimates the SOC of the battery 200 by the method described in the first embodiment. The computing unit 120 learns the correspondence relationship between the SOC acquired by the BMU and the SOC estimated by the computing unit 120 in the same manner as in the second embodiment. The computing unit 120 inputs the new SOC acquired by the BMU into the learning model after the learning results have been accumulated to a certain extent, thereby obtaining the SOC estimation result.

＜Embodiment 4＞ In Embodiment 4 of the present invention, a method of estimating the SOH (or internal resistance Ri, hereinafter the same) of the battery 200 described in Embodiments 1 to 3 will be described. The configuration of the battery management device 100 is the same as that of the above embodiment, but it may also be modified as shown below. The same modified examples can also be adopted in other embodiments.

FIG. 9 is a diagram showing 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 detection unit 130 described in FIG. 3 is shown. In FIG. 9 , 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 detection unit 150 included in the battery management device 100 receives the detection values, for example, via a network, and the calculation unit 120 uses the detection values to calculate the SOH.

FIG. 10 shows a configuration example when the detection unit 130 is connected to the battery 200 . The detection 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 detection 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.

FIG. 11 is a flowchart illustrating the procedure for calculating Ri and SOH by the computing unit 120 . The calculation unit 120 starts this flowchart at an appropriate timing such as every predetermined period when the battery management device 100 is started, for example, when it is instructed to start this flowchart. Each step in Fig. 11 will be described below.

(FIG. 11: Step S1101) Calculator 120 determines whether it is a rest period after charging or a rest period after discharge. If it is not a rest period, this flow chart is ended. If it is a rest period, proceed to S1102. For example, during the rest period after discharge, the current output by the battery 200 changes from a negative value (I<0) toward zero, (b) changes from a negative value toward a value near zero to stabilize (|I|< Threshold value) and so on to judge.

(FIG. 11: Step S1102) 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 counted time after the end of the rest period to the first time when the first period ta elapses. 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.

(FIG. 11: Step S1103) The calculating part 120 calculates Ri and SOH according to the following formula 1 and formula 2. The f _Ri system defines Ri as a function of ΔVa. f _Ri has a parameter (c_Ri_T) that varies depending on the temperature of the battery 200 and a parameter (c_Ri_I) that varies depending on 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 depending on the temperature of the battery 200 and a parameter (c_SOH_I) that varies depending on the output current of the battery 200 . These parameters are defined by relational table 141 . 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, for example, formulas formed based on experimental data for each lot.

(FIG. 11: Step S1103: calculation formula)

FIG. 12 is a graph showing changes over time in current and voltage output from the battery 200 during a rest period after discharge. ΔVa in S1102 is the amount of variation in the output voltage of the battery 200 from the time point after the end of discharge or the first counted time point thereafter to the first time point when the first period ta elapses. The inventors of the present invention have found that the output voltage immediately after discharge fully exhibits a voltage fluctuation due to the internal resistance of the battery 200 . That is, it can be said that the variation (ΔVa) of the output voltage during this period has a strong correlation with Ri. In this embodiment, this fact is utilized, and Ri is estimated 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 time-dependent change curve of the voltage. Wherein, when specifying the above-mentioned section, if it is formed in accordance with the battery type, device, precision, etc., it may be appropriately and preferably formed in the vicinity of both ends of the above-mentioned section, or an area including both ends.

ΔVb in S1102 is the amount of 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 have found that ΔVa immediately after the end of discharge correlates with Ri, whereas thereafter, during the period when the output voltage fluctuates gently, correlates with SOH. In this embodiment, this fact is utilized, and SOH is estimated from ΔVb. The optimal value of each of the start time and time length of tb can be determined from the maximum point of the slope change rate in the voltage time-varying curve after the end of discharge until the slope change of the voltage time-varying curve asymptotically becomes constant. range to obtain. Wherein, when specifying the above-mentioned section, if it is formed in accordance with the battery type, device, precision, etc., it may be appropriately and preferably formed in the vicinity of both ends of the above-mentioned section, or an area including both ends.

The start time of ta may not necessarily be the same as the end time of discharge, but 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 a relationship of ta < tb. Regarding the magnitude of ΔVa and the magnitude of ΔVb, ΔVa may be large, or ΔVb may be large. Wherein, ta<tb is formed here, but depending on the type, device, precision, etc. of the battery, ta>tb or ta=tb may also be the case, 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, Ri and SOH can be simultaneously estimated rapidly during the idle period.

FIG. 13 is a graph showing changes over time in current and voltage output from the battery 200 during a rest period after charging. ΔVa in S1102 may be a variation in the output voltage of the battery 200 from the time point after the end of charging or the first starting time point thereafter to the first time point when the first period ta elapses instead of discharging. At this time, ΔVb in S1102 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 S1102 can also be obtained after charging and discharging.

FIG. 14 is a diagram showing the structure of the relationship table 141 and an example of data. The relationship table 141 is a data table defining parameters in Equation 1 and Equation 2, and is stored in the storage unit 140 . 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 , and therefore 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.

If f _Ri is a linear function of ΔVa, Ri can be represented by, for example, Equation 3 below. 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.

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.

＜Embodiment 5＞ FIG. 15A shows an example of a situation where the battery management device 100 estimates the SOC of the battery 200 . The charging operation described in the first embodiment can be implemented by, for example, a charger for charging an electric device equipped with the battery 200 . Assume, for example, that battery 200 is mounted in electric vehicle 1500 (electrical equipment). The worker connects the charging port 1501 included in the electric vehicle 1500 to the charger 1502 and charges the battery 200 . At this time, the measuring device 1503 disposed between the charger 1502 and the charging port 1501 measures the battery voltage and transmits the result to the battery management device 100 . The battery management device 100 and the measuring device 1503 can be connected via a network, for example. The computing unit 120 uses the battery voltage obtained by the meter 1503 to estimate the SOC by the method described in the first embodiment.

In order to use the estimation method described in Embodiment 1, the charging operation by the charger must be performed twice. Therefore, as described in Embodiment 1, the operator performs the charging operation twice. The computing unit 120 obtains the battery voltage from the measuring device 1503 during the rest period after each charging operation. As the rest period, the period after the operator stops the charging operation can be used.

FIG. 15B shows an example of a situation where the battery management device 100 estimates the SOC of the battery 200 . Similar to FIG. 15A , the battery 200 is loaded in, for example, an electric vehicle, and the operator performs the charging operation through the charging port. The operator also connects an OBD (On Board Diagnostics) terminal 1504 to the electric vehicle. The OBD terminal 1504 measures the battery voltage and transmits the result to the battery management device 100 . The battery management device 100 and the OBD terminal 1504 can be connected via a network, for example. The calculation unit 120 uses the battery voltage obtained by the OBD terminal 1504 to estimate the SOC by the method described in the first embodiment.

Fig. 16 shows an example of the discharge operation. The discharge operation can be implemented by operating an electric load connected to an electric device on which the battery 200 is mounted. If the battery 200 is mounted in the electric vehicle 1500 , the battery 200 can be discharged by, for example, operating an air conditioner included in the electric vehicle 1500 . When the air conditioner is turned off, the battery 200 is in a rest period. The battery voltage during the idle period can be measured by the OBD terminal 1504, for example. The subsequent actions are the same. An air conditioner is an example of an electrical load, and other electrical loads may be used to discharge the battery 200 .

＜Embodiment 6＞ Fig. 17 is a configuration diagram of a power system 1700 according to Embodiment 6 of the present invention. The power system 1700 is a system that supplies electric power output by the solar cell 1701 and the battery 200 to the power system, respectively. The solar battery 1701 is driven by a power control device 1702 , and the battery 200 is driven by a power control device 1703 . The power control device 1703 measures the output voltage of the battery 200 and the like, and uploads the measurement results to the data server. The battery management device 100 estimates the SOC of the battery 200 using the uploaded measurement results. The management server 1704 controls the entire power system 1700 . Instructions to the power control devices 1702 and 1703 are transmitted by, for example, the battery management device 100 or the management server 1704 through a PLC (programmable logic controller). The power control devices 1702 and 1703 respectively control the solar battery 1701 and the battery 200 according to the instruction.

FIG. 18 is an example of an operation schedule of the power system 1700 . When the power system 1700 is connected to the power system, it may be required to present an operation schedule (for example, the amount of power generation at each time point) to the regulatory agency in advance. The operation schedule is created based on the predicted result of the power generation amount of the solar cell 1701 during the operation period. However, there is a relatively high possibility that the predicted value of the power generation amount of the solar cell 1701 deviates from the actual value. Even in this case, in order to make the electric power supplied by the electric power system 1700 follow the operation schedule, the battery 200 may be used as an auxiliary. The remaining power is used to charge the battery 200 , and the insufficient power can be replenished by discharging from the battery 200 .

In order to use the battery 200 as described above, it is necessary to prepare the SOC of the battery 200 in a state suitable therefor. As a prerequisite, it is necessary to accurately measure the SOC of the battery 200 . The battery management device 100 estimates the SOC by the method described in the above embodiments. The operator of the electric power system 1700 can prepare the battery 200 in advance according to the estimation result.

If the operation schedule of the power system 1700 is, for example, 06:00-18:00, the SOC of the battery 200 must be prepared before 06:00. In the example of FIG. 18, this is prepared during period 1802. In addition, based on the premise, the SOC is estimated in the period 1801 before the period 1802 . In order to fully ensure the preparation period, the period 1801 is preferably short.

＜Embodiment 7＞ FIG. 19 is an example of the user interface provided by the battery management device 100 . The user interface can present the SOC estimation result of the battery 200, the measurement results such as ΔV12 or ΔV23 described in the first embodiment, the change over time of the battery voltage obtained by the BMU, and the like. The user interface can, for example, be generated by the computing unit 120 and displayed on an appropriate display element, or the computing unit 120 can generate data describing the user interface (for example, data specifying screen layout such as HTML data) and display it to others. The terminal sends a message, and the display terminal depicts this. It may also be provided by other appropriate means.

<Modification of the present invention> The present invention includes various modified examples, and is not limited to the aforementioned embodiments. For example, the above-mentioned embodiments are described and 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 embodiment, the detection unit 130 obtains the measurement results of the battery voltages V1-V3 from the BMU, but it can also be obtained from any measurement device other than the BMU (for example, the measuring device 1503 or the OBD terminal 1504 described in Embodiment 5). ) to get this.

In the above embodiment, the computing unit 120 can also be constituted by hardware such as circuit elements with its functions, and can also be executed by a computing device such as a CPU (Central Processing Unit, central processing unit). Functional software constitutes.

100: battery management device 110: Department of Communications 120: Computing department 130: Detection Department 131: Voltage sensor 132: Temperature sensor 133: Current sensor 140: memory department 141: Relation table 150: Detection department 200: battery 1500: Electric vehicles 1501: Charging port 1502: Charger 1503: Measuring device 1504: OBD terminal 1700: Power Systems 1701: solar cell 1702, 1703: Electrical control devices 1704: Manage server 1801,1802: period I: current T: temperature V: Voltage

[Fig. 1] is a schematic diagram showing how the BMU acquires the SOC of the battery cell. [Fig. 2] is an example of the waveform of the battery voltage measured or acquired by the BMU during the discharge operation of the battery. [ Fig. 3 ] is a configuration diagram of the battery management device 100 according to the first embodiment. [ FIG. 4 ] shows an example of the discharge operation when the battery management device 100 estimates the SOC of the battery 200 . [ Fig. 5] Fig. 5 is a graph showing the relationship between the battery voltage and the SOC at the point in time when the temporal variation of the battery voltage becomes stable after the start of the rest period. [FIG. 6] It is a figure which shows the example of the data used for estimating the SOC of the battery 200 by the calculation part 120, and the estimation procedure of SOC using this data. [ Fig. 7] Fig. 7 is a schematic diagram illustrating a procedure for estimating the SOC by the calculation unit 120 using the battery voltage obtained by the BMU. [FIG. 8] It is a schematic diagram explaining the procedure of estimating SOC by the battery management apparatus 100 of Embodiment 3. [FIG. [ FIG. 9 ] is a diagram showing another configuration example of the battery management device 100 . [ FIG. 10 ] shows a configuration example when the detection unit 130 is connected to the battery 200 . [FIG. 11] It is a flowchart explaining the procedure which the calculation part 120 calculates Ri and SOH. [ FIG. 12 ] is a graph showing changes over time in the current and voltage output from the battery 200 during the rest period after discharge. [ FIG. 13 ] is a graph showing changes over time in the current and voltage output from the battery 200 during the rest period after charging. [FIG. 14] It is a figure which shows the structure of the relationship table 141, and a data example. [ FIG. 15A ] is an example of a situation where the battery management device 100 estimates the SOC of the battery 200 . [ FIG. 15B ] is an example of a situation where the battery management device 100 estimates the SOC of the battery 200 . [Fig. 16] shows an example of discharge operation. [ Fig. 17 ] is a configuration diagram of a power system 1700 according to the sixth embodiment. [ FIG. 18 ] is an example of the operation schedule of the electric power system 1700 . [ FIG. 19 ] is an example of the user interface provided by the battery management device 100 .

Claims (14)

A battery management device, which is a battery management device for managing the state of a battery, characterized by: have: a detection unit that obtains a detection value of a voltage output from the battery, a calculation unit for estimating the state of the battery, The calculation unit calculates the output voltage of the battery at the time point when the battery starts the first charging operation or the first discharging operation, and the output voltage after the first rest period after the completion of the first charging operation or the first discharging operation. the first difference between the output voltages of the aforementioned batteries at the point in time when the first time has elapsed, The calculation unit calculates the output voltage of the battery at the time point when the battery starts the second charging operation or the second discharging operation after the end of the first rest period, and the output voltage after the second charging operation or the second discharging operation is completed. The second difference between the output voltages of the aforementioned batteries at the point in time when the second time elapses after the start of the second rest period, The calculation unit estimates the state of charge of the battery by referring to data describing a relationship between the first difference, the second difference, and the state of charge of the battery. The battery management device according to claim 1, wherein the above-mentioned data is described as: the value of converting the charge or discharge of the battery from the start to the end of the charge or discharge of the battery into the value of the state of charge, and the start of charge of the battery. Or the relationship between the change in the output voltage of the aforementioned battery after discharge to the end, The calculation unit uses the first difference to refer to the data, thereby obtaining a first candidate for the state of charge corresponding to the charging amount or discharging amount of the battery in the first charging operation or the first discharging operation, The calculation unit uses the second difference to refer to the data, thereby obtaining a second candidate for the state of charge corresponding to the charging amount or discharging amount of the battery in the second charging operation or the second discharging operation, The calculation unit estimates the state of charge by specifying the charge amount in the second charging operation or the discharge amount in the second discharge operation among the first candidates and the second candidates. The battery management device according to claim 1, wherein the above-mentioned data is described as: the value of converting the charge or discharge of the battery from the start to the end of the charge or discharge of the battery into the value of the state of charge, and the start of charge of the battery. Or the relationship between the change in the output voltage of the aforementioned battery after discharge to the end, The calculation unit estimates the charge by identifying the first difference, the second difference, and the difference between the first difference and the second difference among the data points described in the data. state. The battery management device according to claim 1, wherein the aforementioned computing unit is based on: The first output voltage of the battery at the time when the first charging operation or the first discharging operation is started, The second output voltage of the battery at the point in time when the first time has elapsed since the start of the first rest period, The third output voltage of the battery when the second time elapses after the start of the second rest period, for each combination to estimate the aforementioned state of charge, The calculation unit is a measuring device that measures the output voltage of the battery independently of the battery management device, and obtains the measurement results of the first output voltage, the second output voltage, and the third output voltage, The calculation unit learns the correspondence relationship between the state of charge estimated for each combination and the measurement result, The calculation unit estimates the state of charge by inputting the new measurement result obtained by the measurement device into the learned correspondence relationship. The battery management device according to claim 1, wherein the calculation unit estimates the deterioration state of the battery, The calculation unit calculates the state of charge at the time when the first charging operation starts using the state of degradation. The battery management device according to claim 5, wherein the detection unit obtains a detection value of the current output by the battery, The computing unit acquires a first voltage between the voltage at a first starting time after the battery finishes charging or discharging, and the voltage at a first time after a first period has elapsed from the first starting time. 1 difference, as a difference representing the temporal change of the voltage output by the aforementioned battery, The calculation unit obtains, as the difference, a second difference between the voltage at a second starting time after the first time and the voltage at a second time after a second period has elapsed from the second starting time. , The computing unit obtains relation data describing the relationship between the first difference and the internal resistance of the battery, and describing the relationship between the second difference and the deterioration state, The calculation unit uses the first difference to refer to the relational data, thereby estimating the internal resistance of the battery, The computing unit estimates the deterioration state by referring to the relationship data using the second difference. The battery management device according to claim 1, wherein the first charging operation and the second charging operation are performed through a charging port of an electric device loaded with the battery, The calculation unit calculates the first difference and the second difference generated by the first charging operation and the second charging operation performed through the charging port, respectively. The battery management device according to claim 7, wherein the computing unit is a measuring device disposed between the charging port and the charger, or a terminal connected to the electric device to perform maintenance processing on the electric device , obtained respectively: The first output voltage of the battery at the time when the first charging operation or the first discharging operation is started, The second output voltage of the battery at the point in time when the first time has elapsed since the start of the first rest period, The third output voltage of the battery when the second time elapses after the start of the second rest period. The battery management device according to claim 1, wherein the first discharging operation and the second discharging operation are performed by an electrical load of an electrical device equipped with the battery, The calculation unit acquires the first difference and the second difference generated by the first discharge operation and the second discharge operation performed by the electrical load, respectively. The battery management device according to claim 1, wherein the first charging operation and the second charging operation, or the first discharging operation and the second discharging operation are performed by driving the battery control device, The calculation unit obtains: the first charging operation and the second charging operation performed by the control device, or the first discharging operation and the second discharging operation performed by the control device. The aforementioned first difference and the aforementioned second difference generated by the action. The battery management device according to claim 10, wherein the control device implements the charging or discharging of the battery according to the operation schedule preset according to the power demand, The control device executes the first charging operation and the second charging operation, or the first discharging operation and the second discharging operation before charging or discharging the battery according to the operation schedule, The calculation unit estimates the state of charge before the control device performs charging or discharging of the battery according to the operation schedule. The battery management device according to claim 1, wherein the battery management device has a user interface that prompts the estimated charging state. A battery management program, which is a battery management program that causes a computer to execute processing for managing the state of a battery, wherein the computer executes: The step of obtaining the detection value of the voltage output by the aforementioned battery, the step of estimating the state of the aforementioned battery, In the step of estimating, the computer is made to execute: calculating the output voltage of the battery at the time point when the battery starts the first charging operation or the first discharging operation, and the output voltage when the first charging operation or the first discharging operation is completed. step of making a first difference between the output voltages of the aforementioned batteries at a point in time when a first time elapses after the start of the first rest period, In the step of estimating, the computer is made to execute: calculating the output voltage of the battery at the time point when the battery starts the second charging operation or the second discharging operation after the end of the first rest period, and the second charging operation or the second difference between the output voltages of the battery at the point in time when the second time elapses after the start of the second rest period after the second discharge operation is completed, In the estimating step, causing the computer to execute the step of estimating the state of charge of the battery by referring to data describing the relationship between the first difference, the second difference, and the state of charge of the battery. A method of managing the state of the battery using a battery management device that manages the state of the battery, The aforementioned battery management device has: a detection unit that obtains a detection value of a voltage output from the battery, a calculation unit for estimating the state of the battery, The calculation unit calculates the output voltage of the battery at the time point when the battery starts the first charging operation or the first discharging operation, and the output voltage after the first rest period after the completion of the first charging operation or the first discharging operation. the first difference between the output voltages of the aforementioned batteries at the point in time when the first time has elapsed, The calculation unit calculates the output voltage of the battery at the time point when the battery starts the second charging operation or the second discharging operation after the end of the first rest period, and the output voltage after the second charging operation or the second discharging operation is completed. The second difference between the output voltages of the aforementioned batteries at the point in time when the second time elapses after the start of the second rest period, The calculation unit estimates the state of charge of the battery by referring to data describing the relationship between the first difference, the second difference, and the state of charge of the battery, The aforementioned method system has: The steps of implementing the aforementioned first charging operation and the aforementioned second charging operation through a charging port of an electric device loaded with the aforementioned battery, A step of measuring the output voltage of the battery using a measuring device disposed between the charging port and the charger, or using a terminal connected to the electric device for performing maintenance on the electric device, The step of estimating the state of charge by the battery management device using the output voltage.

Images