JP2006343230A - Detector for residual capacity of storage battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a detector for the residual capacity of a storage battery, capable of stably and precisely detecting the residual capacity of a storage battery. <P>SOLUTION: The detector includes a voltage detecting section 3 for measuring the voltage of the storage battery, a current detector 4 for measuring the current flowing in the storage battery, a mean value calculating section 5 for calculating the mean value of voltages and a mean value of currents during a predetermined time, a characteristic data storing section 6 for storing the relation between voltages and currents preacquired, and an average residual capacity estimating section 7 for estimating the residual capacity of the storage battery from the relation between the mean value of the voltages and the mean value of the current and the relation between the voltages and the currents that are acquired in advance. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a storage battery remaining capacity detection device that stably and accurately detects a remaining capacity of a storage battery.

In the conventional storage battery remaining capacity detection device, the internal resistance of the storage battery is obtained from the relationship between the starter current and the terminal voltage of the storage battery, and the SOC (State of Charge) that is the remaining capacity of the storage battery immediately before traveling is detected. There is a remaining capacity estimation method based on current integration in which a charge amount or a discharge amount is detected by integrating a current, and a remaining capacity of a storage battery is detected by comparing an initial capacity and a charge / discharge amount (see, for example, Patent Document 1). ).
In addition, the magnitude of the current flowing through the storage battery and the voltage between the terminals of the storage battery are detected, the internal resistance of the storage battery is obtained from these detected values, and the remaining capacity of the storage battery is determined from the correlation between the internal resistance of the storage battery and the remaining capacity of the storage battery. There is also a remaining capacity estimation method using OCV (Open Circuit Voltage) which is an open terminal voltage for detecting capacity (for example, see Patent Document 2).

JP-A-53-127646 (2nd page, Fig. 1) JP-A-5-172913 (page 3-4, FIG. 1)

The charging / discharging of the storage battery has a very long time constant, and even after charging or discharging, the terminal voltage of the storage battery approaches the steady value very slowly, so it is very long from the end of charging or discharging. If the time does not elapse, the remaining capacity of the storage battery cannot be accurately detected from the open terminal voltage of the storage battery. In particular, when discharging and charging are repeated with a very large current as in a hybrid vehicle, the influence of the current history of charging and discharging on the open terminal voltage is very large. Therefore, there is a problem that it is impossible to accurately measure the remaining capacity of the storage battery.
On the other hand, the remaining capacity estimation method using current integration has relatively high detection accuracy. However, in order to estimate the remaining capacity of the storage battery, the remaining capacity value of the storage battery in the prior operation period is required. For this reason, errors that occur during prior driving affect subsequent estimations, and errors may accumulate over time, and cannot be used for traveling where charging and discharging are repeated frequently. When a long time elapses from the initial setting of the remaining capacity, the reliability is lowered.

  The present invention has been made to solve the above-described problems, and provides a storage battery remaining capacity detection device capable of detecting the remaining capacity of a storage battery stably and accurately.

  The storage battery remaining capacity detection device according to the present invention includes a voltage detection means for measuring the voltage of the storage battery, a current detection means for measuring a current flowing through the storage battery, an average value for calculating a voltage average value and a current average value for a predetermined time. The storage battery remaining capacity is calculated from the value calculation means, the characteristic data storage means storing the relationship between the voltage and current acquired in advance, the relationship between the average value of voltage and the average value of current, and the relationship between voltage and current acquired in advance. And an average remaining capacity estimating means for estimating.

  The storage battery remaining capacity detection device according to the present invention includes a voltage detection means for measuring the voltage of the storage battery, a current detection means for measuring a current flowing through the storage battery, an average value for calculating a voltage average value and a current average value for a predetermined time. The storage battery remaining capacity is calculated from the value calculation means, the characteristic data storage means storing the relationship between the voltage and current acquired in advance, the relationship between the average value of voltage and the average value of current, and the relationship between voltage and current acquired in advance. Since the estimated average remaining capacity estimating means is provided, a storage battery remaining capacity detecting device capable of detecting the remaining capacity of the storage battery stably and accurately can be obtained.

Embodiment 1 FIG.
FIG. 1 is a block diagram of a storage battery remaining capacity detection device showing Embodiment 1 for carrying out the present invention. The storage battery 1 supplies power to the load 2. The voltage detection unit 3 is a voltage detection unit that measures the voltage of the storage battery 1. The current detection unit 4 is a current detection unit that measures the current flowing through the storage battery 1. The average value calculation unit 5 is an average value calculation unit that calculates the average value of the voltage measured by the voltage detection unit 3 during a predetermined time and the average value of the current measured by the current detection unit 4 during the predetermined time. The characteristic data storage unit 6 is characteristic data storage means for storing the relationship between the voltage and current acquired in advance. The average remaining capacity estimator 7 estimates the remaining battery capacity based on the cycle average from the relationship between the average value of the voltage and the average value of the current measured during a predetermined time and the relationship between the voltage and the current acquired in advance. Capacity estimation means. The storage battery remaining capacity detection device 11 includes a voltage detection unit 3, a current detection unit 4, an average value calculation unit 5, a characteristic data storage unit 6, and an average remaining capacity estimation unit 7.

  As a device or apparatus equipped with the storage battery remaining capacity detection device, there is a vehicle including an electric motor that converts electric power of the storage battery 1 into motive power, generates electric power with braking force, and stores the electric power. There is also a hybrid vehicle equipped with an internal combustion engine in this vehicle. FIG. 2 shows the relationship between the speed related to the traveling of the hybrid vehicle and the DC current flowing through the storage battery 1. In FIG. 2, the horizontal axis represents elapsed time. First, when starting and accelerating, a very large discharge current flows. Next, the current value is not so large when performing constant speed operation. After that, when decelerating and stopping, charging is performed with a regenerative current, and a very large current flows into the storage battery 1 in the reverse direction. In the storage battery 1, a charging / discharging pattern including charging and discharging is repeatedly performed from the start to the stop of the vehicle.

  FIG. 3 shows the relationship between the DC current flowing through the storage battery 1 of the hybrid vehicle shown in FIG. 2 and the terminal voltage of the storage battery 1. In the case of a discharge current in which a current flows from the storage battery 1, the terminal voltage is lowered by the amount corresponding to the internal resistance of the storage battery 1. On the other hand, in the case of a charging current in which a current flows into the storage battery 1, the terminal voltage becomes high. From FIG. 3, it can be seen that the voltage changes considerably delayed with respect to the change in current. That is, although the change in the terminal voltage and the internal resistance of the storage battery 1 are correlated, the voltage value of the storage battery 1 cannot be determined only from the internal resistance and the current value. Further, the time constant of the voltage and current of the storage battery 1 is very long, for example, 1 hour, and the voltage does not reach a steady value while the hybrid vehicle is running. Cannot make an estimate.

  Therefore, the average of the voltage of the storage battery 1 measured by the voltage detector 3 during the period of one driving cycle from the start of the vehicle shown in FIG. 2 (left end of the graph of FIG. 2) to stop (right end of the graph of FIG. 2). The value is calculated by the average value calculation unit 5. Similarly, the average value calculation unit 5 calculates the average value of the current flowing through the storage battery 1 measured by the current detection unit 4 during the period of one driving cycle from the start to the stop of the vehicle. The time for calculating the average value needs at least one operation cycle. That is, the storage battery 1 repeatedly performs a charge / discharge pattern including charging and discharging, and the charge / discharge pattern is performed at least once within a predetermined time for calculating the average value.

  FIG. 4 shows the time variation of the terminal voltage with respect to the remaining capacity of the storage battery 1 when the storage battery 1 is in a discharged state on average. In FIG. 4, the broken line is the time change of the terminal voltage when charging / discharging with the current pattern of one operation cycle as shown in FIG. The solid line represents the time variation of the terminal voltage when the storage battery 1 is discharged from the fully charged state with a constant current of 18A. FIG. 4 shows how the average value of the terminal voltage changes in one operation cycle. The change in the terminal voltage when discharged at a constant current is almost equal to the change in the average value of the terminal voltage in one operation cycle when charging and discharging are repeated.

  The reason why the change in the terminal voltage when discharged at a constant current and the change in the average value of the terminal voltage in one operation cycle in which charging and discharging are repeated are substantially the same as follows. One driving cycle includes high-rate charging and high-rate discharging at the same time. The vehicle stops at the beginning and end of one driving cycle, and the current value is zero when the vehicle is stopped. For this reason, the voltage increase due to the charging current and the voltage decrease due to the discharging current are canceled during one operation cycle. In addition, the delay in the response to the voltage change due to the time constant is canceled between successive operation cycles.

  FIG. 5 shows the time variation of the terminal voltage with respect to the remaining capacity of the storage battery 1 when the storage battery 1 is in an average charged state. In FIG. 5, the broken line is the time variation of the terminal voltage when charging / discharging with a current pattern of one operation cycle as shown in FIG. The storage battery 1 starts from a state where the remaining capacity is almost zero. The solid line represents the change over time of the terminal voltage when the battery 1 is charged from a state where the current is constant at 16 A and the remaining capacity of the battery 1 is zero. FIG. 5 shows how the average value of the terminal voltage changes in one operation cycle. The change in the terminal voltage when charged with a constant current is substantially equal to the change in the average value of the terminal voltage in one operation cycle when charging and discharging are repeated.

  The change in the terminal voltage when discharging or charging with a constant current shown in FIGS. 4 and 5 corresponds to the voltage when the voltage change sufficiently reaches a steady value, that is, the remaining capacity of the storage battery 1 at that time. The value is determined by the open terminal voltage, current value, and internal resistance. For this reason, if the voltage characteristics of discharging or charging at a constant current are acquired for several current values and stored in the characteristic data storage unit 6 as the relationship between the voltage and current acquired in advance, the average The remaining capacity of the storage battery 1 can be estimated from the relationship between the average value of the voltage and the average value of the current measured during one operation cycle in the remaining capacity estimation unit 7 and the relationship between the voltage and the current acquired in advance.

  FIG. 6 shows an example of the relationship between the voltage and current acquired in advance. The method for obtaining the relationship between the voltage and current is as follows. First, a change in voltage when charging / discharging at a constant current is measured. Since charging / discharging is performed at a constant current, the remaining capacity of the storage battery 1 can be accurately estimated, and this measurement data relates the current value, the voltage value, and the remaining capacity value of the storage battery 1. Next, similar data is measured by changing several current values. As a result, a matrix for estimating the remaining capacity of the storage battery 1 from the current value and the voltage value can be configured. In FIG. 6, the horizontal axis represents the current value, the vertical axis represents the voltage value, and each remaining capacity value is represented as a contour graph. 6 shows the current-voltage characteristic of the storage battery 1, and the slope of this characteristic represents the internal resistance of the storage battery 1.

  If the current value and the voltage value are known from FIG. 6, the remaining capacity of the storage battery 1 can be estimated. The time change of the terminal voltage and current of the storage battery 1 during traveling is measured, and the average value of the time change of voltage and current is obtained during the period from when the hybrid vehicle stops until it stops next. The remaining capacity value of the storage battery 1 can be obtained by comparing the average value of the current voltage in one operation cycle with the matrix of FIG. Such a method for estimating the remaining capacity of the storage battery 1 is referred to as a remaining capacity estimating method based on cycle average.

  In addition, the internal resistance of the storage battery 1 has temperature dependence, and the resistance becomes high particularly at low temperatures. Accordingly, FIG. 6 has temperature dependence, and it is necessary to perform temperature-dependent data or correction for temperature dependence. Further, since the internal resistance also depends on the deterioration state of the battery, it is necessary to perform correction based on the deterioration state of the battery.

  Here, a supplementary explanation will be given of the driving cycle related to the driving of the hybrid vehicle. The driving cycle is a series of operations from the stop of the hybrid vehicle to the start, acceleration, deceleration and stop. Since acceleration and deceleration are included between the previous stop and the next stop, the storage battery 1 is charged and discharged during this time. That is, a series of operations of starting, accelerating, decelerating, and stopping the vehicle is performed at least once in the charge / discharge pattern. The period from the previous stop to the next stop is defined as one operation cycle. The reason for defining a stop at the beginning and end of one operation cycle is that the current flowing into or out of the storage battery 1 is almost zero at the time of stop, so that the first and the end of one operation cycle are substantially the same. It is easy to define as a break of repetition, and it is easy to detect as a system. The remaining capacity estimation method based on cycle averaging can be applied to such an operation cycle.

  In the remaining capacity estimation method based on cycle average, the average value of current and the average value of voltage are measured to cancel the effects of high-rate charging and high-rate discharge, and to approximate the situation where average current flows. is required. For this reason, the predetermined time for calculating the average values of the current and voltage is preferably as long as possible so that the instantaneous instantaneous variation is averaged. Further, if the remaining capacity of the storage battery 1 changes greatly during the average value calculation, the remaining capacity of the storage battery 1 cannot be estimated. Therefore, it is necessary to select a period in which the change in the remaining capacity of the storage battery 1 is sufficiently small. For this reason, a case where one operation cycle is repeated a plurality of times may be one operation cycle which is a predetermined time. In addition, the setting of the predetermined time for calculating the average value of the current and voltage may be a time when a predetermined time has elapsed, or a time when the time integral value of the average value of the current reaches a predetermined value. Also good.

  The time length of one operation cycle may be defined as follows. For example, when an average current of 18 A is passed through the storage battery 1 having a capacity of 50 Ah, the time for the remaining capacity of the storage battery 1 to change by 2% is 200 seconds, and the time for the remaining capacity of the storage battery 1 to change by 10% is 1000 seconds. is there. For this reason, although depending on the driving conditions, it is assumed that the upper limit is 1000 seconds, which is the time for the remaining capacity of the storage battery 1 to change by about 10%, and the vehicle is frequently started and stopped repeatedly, for example, by stopping at a signal in an urban area. Thus, 30 seconds can be set as the lower limit.

  On the other hand, it is possible to apply the remaining capacity estimation method based on the cycle average according to the present invention without necessarily repeating the start or stop. For example, when the operation is stopped for a long time, obtaining the average value of the current and the average value of the voltage is similar to the estimation of the remaining capacity by the open terminal voltage after a long time in principle. Therefore, if the stop time is sufficiently long, the remaining capacity of the storage battery 1 can be estimated with sufficient accuracy from the respective average values. In addition, when traveling for a long time at a substantially constant speed, such as traveling on a highway, obtaining the average value of the substantially constant current and the average value of the voltage is the change in voltage during discharge at a constant current or It is the same as measuring the voltage change at the time of charge, and the remaining capacity of the storage battery 1 can be estimated in principle.

  By the way, when the average value of the current in one operation cycle is high, it is difficult to estimate the remaining capacity of the storage battery 1 accurately. FIG. 7 shows the time change of the terminal voltage with respect to the remaining capacity of the storage battery 1 when the storage battery 1 is in a discharged state on average. In FIG. 7, the broken line is the time change of the terminal voltage when charging / discharging with a current pattern of one operation cycle as shown in FIG. The solid line represents the change over time of the terminal voltage when the storage battery 1 is charged from the fully charged state with the current kept constant at 36A. It can be seen from FIG. 7 that the change in the average value of the terminal voltage in one operation cycle is different from the change in the terminal voltage when discharged at a constant current. This is because, when the remaining capacity of the storage battery 1 is large, charging is performed at a high rate, so that the charging current does not contribute to the charging of the storage battery 1, the charging efficiency is low, and the discharge is performed at a constant current. It seems that the state of charge and discharge is quite different.

  FIG. 8 shows the standard deviation obtained from the difference between the change in the average value of the terminal voltage in one operation cycle when the average value of the current in one operation cycle is changed and the change in the terminal voltage when discharged at a constant current. The measurement results are shown. In FIG. 8, the horizontal axis represents the average value of current in one operation cycle, and the vertical axis represents the standard deviation. When the average value of the current in one operation cycle is 20 A or more, the difference between the change in the average value of the terminal voltage in one operation cycle and the change in the terminal voltage when discharged at a constant current increases. Even in the charged state, when the average value of the current is 20 A or more, the difference between the change in the average value of the voltage in one operation cycle and the change in the voltage when discharged at a constant current is large.

  From this, when the average value of the current is 20 A or less, the remaining capacity of the storage battery 1 can be estimated with relatively high accuracy by the remaining capacity estimation method based on the cycle average. Note that when the average value of the current in one operation cycle is 20 A or more, the relationship between the voltage and current acquired in advance may be corrected in anticipation that the voltage is set higher in advance. In the above description, a current value of 20 A is shown. Since this was performed using a storage battery with a capacity of 50 Ah, it can be normalized to 0.4 C by the capacity of the storage battery. However, this value varies depending on the type of storage battery and the usage environment.

  Now, the shape of the current flowing through the storage battery 1 varies greatly depending on the traveling pattern of the vehicle. In particular, in the case of a hybrid vehicle, charging by the internal combustion engine is also performed separately. In addition, since a very long time constant exists in the change in voltage, the change in voltage due to the previous travel always affects. If the same charging / discharging is performed every time, the influence of this time constant is considerably canceled. However, since the same traveling cannot be repeated in actual traveling, the remaining capacity estimation method based on the cycle average is not a complete estimation method.

  However, the remaining capacity of the storage battery 1 can be estimated almost accurately under specific conditions. The remaining capacity estimation method based on the cycle average has a decisive advantage compared with the remaining capacity estimation method based on the open terminal voltage and the remaining capacity estimation method based on current integration. In the remaining capacity estimation method based on the open terminal voltage, it is impossible to accurately estimate the remaining capacity of the storage battery 1 while traveling unless a time corresponding to the time constant of the voltage change has elapsed. On the other hand, in the remaining capacity estimation method based on cycle averaging, the delay including the response delay of the voltage change due to the time constant is averaged, so that the influence is canceled and the remaining capacity of the storage battery 1 is relatively accurate even during traveling. Can be estimated.

  On the other hand, the remaining capacity estimation method based on current integration requires the remaining capacity value of the storage battery 1 in the previous operation period in order to estimate the remaining capacity of the storage battery 1, so that an error generated during the previous operation may be This may affect the estimation of the remaining capacity of the storage battery 1, and errors may accumulate with time. Moreover, since the initial value of the remaining capacity of the storage battery 1 is required, another method for estimating the remaining capacity of the storage battery 1 is necessarily required. On the other hand, in the remaining capacity estimation method based on the cycle average, the estimation is performed based on the current value and the voltage value at that time.

  The remaining capacity estimation method based on cycle averaging is particularly effective for application to hybrid vehicles such as railways, route buses, and trams. In hybrid vehicles such as railroads, route buses, and trams, in addition to the purpose of improving fuel efficiency, when driving in urban areas to protect the environment, the vehicle only runs on batteries and runs in the suburbs to suppress exhaust emissions. In such a case, an operation method of charging by moving the internal combustion engine is also conceivable. The remaining capacity estimation method based on cycle average can also be applied to new transportation systems such as low-floor trains and new trams.

  Railways, route buses, trams, and other transportation systems run at extremely high speeds, and often travel on a fixed route with few rapid accelerations and decelerations with high-rate charging and discharging. In addition, there is a feature such that the operating time zone is determined, and the vehicle stops at a garage for a certain period of time, mainly at night, and stops at a stop at a predetermined interval. This type of operation is suitable for the remaining capacity estimation method based on cycle averaging.

  If the charge / discharge at a high rate is small, the change in the voltage is also small, so that the accuracy of the remaining capacity estimation method by cycle averaging is high. In the case of railways, route buses, trams, etc., high-rate traveling is reduced, and the range in which the remaining capacity estimation method based on cycle averaging can be applied is widened. Further, since the vehicle is stopped in the garage for a certain time or more, mainly at night, the remaining capacity of the storage battery 1 can be estimated stably by the remaining capacity estimation method using the open terminal voltage before departure.

  Furthermore, it is possible to effectively use the stop at the stop. In the remaining capacity estimation method based on cycle averaging, one operation cycle may be from the previous stop to the next stop. That is, the stop at the stop may be one pattern of the driving cycle. When there are stops at predetermined intervals and the vehicle stops there with certainty, the remaining capacity can be estimated by cycle averaging under very stable conditions. The averaging in the cycle average has the purpose of averaging the change in voltage due to charging and discharging, and the purpose of averaging the delay of the response of the voltage change that lasts with a certain time constant. In other words, by repeating the same running, the remaining capacity estimation method based on the cycle average becomes effective. For this reason, in traveling between stops, the same traveling, traveling in the same acceleration and deceleration patterns are repeated, and the remaining capacity can be estimated extremely stably and accurately.

  In the first embodiment, a vehicle or a hybrid vehicle provided with an electric motor that converts the electric power of the storage battery 1 into motive power, generates electric power with a braking force, and stores it as an apparatus or device on which the storage battery remaining capacity detection device is mounted has been described. A device or an apparatus provided with another storage battery may be used.

  As described above, the voltage detection means for measuring the voltage of the storage battery 1, the current detection means for measuring the current flowing through the storage battery 1, the average value calculation means for calculating the average value of the voltage and the average value of the current for a predetermined time, Characteristic data storage means for storing the relationship between the voltage and current acquired in advance, the average remaining value for estimating the remaining capacity of the storage battery from the relationship between the average value of voltage and the average value of current and the relationship between voltage and current acquired in advance Since the capacity estimation means is provided, a storage battery remaining capacity detection device capable of detecting the remaining capacity of the storage battery 1 stably and accurately can be obtained.

Embodiment 2. FIG.
The remaining capacity estimation method based on cycle averaging is a method that is sufficiently effective by itself, but estimation accuracy can be further improved by performing estimation in combination with another remaining capacity estimation method. FIG. 9 is a block diagram of a storage battery remaining capacity detection device showing Embodiment 2 for carrying out the present invention. 9 is different from the first embodiment in that an integrated remaining capacity estimation unit 8, an OCV remaining capacity estimation unit 9, and a system control unit 10 are provided. The accumulated remaining capacity estimating unit 8 is an accumulated remaining capacity estimating unit that estimates the remaining battery capacity from the time integration of the current flowing through the storage battery 1. The OCV remaining capacity estimating unit 9 is a remaining capacity estimating means for estimating the storage battery remaining capacity based on the open terminal voltage. The system control unit 10 controls the average remaining capacity estimation unit 7, the accumulated remaining capacity estimation unit 8, and the OCV remaining capacity estimation unit 9, and among the remaining capacity of the storage battery 1 estimated by these estimation units, the optimum remaining capacity To extract. The storage battery remaining capacity detection device 12 includes a voltage detection unit 3, the current detection unit 4 includes an average value calculation unit 5, a characteristic data storage unit 6, an average remaining capacity estimation unit 7, an integrated remaining capacity estimation unit 8, and an OCV remaining capacity estimation unit. 9 and a system control unit 10.

  The feature of the remaining capacity estimation method based on cycle averaging is that there is less error accumulation as in the remaining capacity estimation method based on current integration. On the other hand, if the remaining capacity estimation method based on current integration obtains the charging efficiency η to some extent accurately, the remaining capacity of the storage battery 1 can be estimated in principle accurately. On the other hand, the cycle average method is theoretically accurate. Have difficulty. That is, the remaining capacity estimation method based on current integration is very accurate immediately after the initial value of the remaining capacity of the storage battery 1 is set, but the error gradually increases as time passes. Although the remaining capacity estimation method based on cycle averaging is not so accurate, the error does not increase over time and is constant. From this, if these two methods having different characteristics of accuracy are combined, the remaining capacity of the storage battery 1 can be estimated with higher accuracy and higher reliability as a system.

  In order to obtain the initial value of the remaining capacity of the storage battery 1, it is conceivable to use a remaining capacity estimation method based on an open terminal voltage. First, regarding the remaining capacity estimation method using the open terminal voltage, the no-load standby time required before measurement will be described. In the remaining capacity estimation method based on the open terminal voltage, it is necessary to measure the voltage after the voltage change due to the effect of charging and discharging has sufficiently settled and reached the steady value, so the time until the voltage reaches the steady value It is better to clarify the no-load standby time.

  Compared to the time constant after charging, the time constant after discharging is short. However, even if the last operation is discharging, if charging is performed immediately before that, the effect of charging lasts only for the time constant of charging. Not reach. Further, in the case of a hybrid vehicle, the battery is stopped while being charged by the regenerative current due to the brake at the end, so that it may be considered that the battery is charged immediately before stopping. Therefore, the time corresponding to the time constant of the voltage change after charging should be selected as the necessary no-load standby time. As an example, as a result of conducting an experiment using a lead storage battery as the storage battery 1, it was confirmed that it reached within 0.05V of the final ultimate voltage after 1 hour 30 minutes after charging and after 15 minutes after discharging. It was done. This corresponds to about 5% in terms of the remaining capacity value of the storage battery 1. Therefore, the remaining capacity of the storage battery 1 can be determined with an accuracy of 5% after 1 hour 30 minutes after charging and after 15 minutes after discharging.

  The remaining capacity estimation method based on the open terminal voltage can measure the remaining capacity of the storage battery 1 more accurately. However, it is necessary that a sufficiently long time elapses with the electrode opened. Depending on the state of operation, it is unclear whether the time necessary for the determination of the open terminal voltage has elapsed from the end of the previous operation to the start of the next operation. For this reason, when the stop time has not sufficiently elapsed, the remaining capacity of the storage battery 1 estimated by the remaining capacity estimation method based on the cycle average is set as an initial value for the period from the stop to the next stop.

  FIG. 10 is a flowchart showing an operation of the storage battery remaining capacity detection device according to Embodiment 2 of the present invention. The operation for detecting the remaining capacity of the storage battery 1 in this embodiment is mainly when the remaining capacity estimation method based on cycle average is used and the remaining capacity estimation method based on current integration is used as an auxiliary. First, in step ST101, driving of the vehicle is started. In step ST102, the stop time of the vehicle is determined. If the stop time is equal to or longer than Ts, in step ST103, the remaining capacity of the storage battery 1 is initialized by the remaining capacity estimation method using the open terminal voltage, and the stop time Ts. If it is less, the value at the previous operation is set to the initial value in step ST104.

  Next, in step ST105, it is determined whether or not the vehicle is stopped. If the vehicle is stopped, in step ST106, the remaining capacity of the storage battery 1 is estimated by the cycle-average remaining capacity estimation method. In step ST107, the remaining capacity of the storage battery 1 estimated by the cycle-average remaining capacity estimation method is estimated. Decide to adopt capacity. In step ST108, the remaining capacity of the storage battery 1 is updated. If the vehicle is not stopped, the remaining capacity of the storage battery 1 is estimated by the remaining capacity estimation method based on current integration in step ST109, and the remaining capacity of the storage battery 1 estimated by the remaining capacity estimation method based on current integration is determined in step ST110. Decide to adopt capacity. In step ST108, the remaining capacity of the storage battery 1 is updated. After updating the remaining capacity of the storage battery 1, the process returns to step ST105. When the vehicle leaves the vehicle, the remaining capacity of the storage battery 1 may be detected by the remaining capacity estimation method using the open terminal voltage, and the remaining capacity of the storage battery 1 is determined by the remaining capacity estimation method using current integration with this detected value as an initial value. May be estimated.

  As described above, it is possible to detect the remaining capacity of the storage battery 1 in a stable and accurate manner by combining the remaining capacity estimation method based on the cycle average, the remaining capacity estimation method based on the open terminal voltage, and the remaining capacity estimation method based on the current integration. A storage battery residual capacity detection apparatus can be obtained.

Embodiment 3 FIG.
When estimating the remaining capacity of the storage battery 1 by the method of estimating the remaining capacity by cycle averaging, as described in the first embodiment, the estimation accuracy of the remaining capacity of the storage battery 1 when the average value of the current flowing through the storage battery 1 increases. Becomes lower. Therefore, in the present third embodiment, when the average value of the current flowing through the storage battery 1 is increased, the remaining capacity of the storage battery 1 is estimated by a remaining capacity estimation method based on current integration.

  FIG. 11 is a flowchart showing the operation of the storage battery remaining capacity detection device according to Embodiment 3 of the present invention. In FIG. 11, step ST101 to step ST104 are the same as those in the second embodiment. In step ST105, it is determined whether or not the vehicle is stopped. When the vehicle is stopped, in step ST106, the remaining capacity of the storage battery 1 is estimated by the remaining capacity estimation method based on the cycle average, and in step ST111, the current cycle average value (the average value of the current in the driving cycle). And the predetermined current Ith are compared. When the current cycle average value is smaller than Ith, in step ST107, it is determined to adopt the remaining capacity of the storage battery 1 estimated by the remaining capacity estimation method based on the cycle average. In step ST108, the remaining capacity of the storage battery 1 is updated. About setting of Ith, it sets to the value from which the difference of the change of the average value of the voltage of 1 driving cycle and the change of the voltage when it discharges with a fixed current becomes large. For example, as shown in Embodiment 1, it may be set to 20A. When the vehicle is not stopped and the average value of the current exceeds Ith, the remaining capacity of the storage battery 1 is estimated by the remaining capacity estimation method by current integration in step ST109, and the remaining capacity by current integration is determined in step ST110. It is decided to adopt the remaining capacity of the storage battery 1 estimated by the capacity estimation method. In step ST108, the remaining capacity of the storage battery 1 is updated. After updating the remaining capacity of the storage battery 1, the process returns to step ST105.

  As described above, the remaining capacity of the storage battery 1 is basically estimated by the remaining capacity estimation method based on the cycle average. From the stop to the next stop, whether the remaining capacity of the storage battery 1 estimated by the remaining capacity estimation method based on the cycle average is an initial value, and whether or not there is a large deviation from the remaining capacity of the storage battery 1 estimated by the remaining capacity estimation method based on current integration Confirm. In addition, even if the vehicle is stopped, if the current cycle average value exceeds Ith, the remaining capacity estimation method based on the cycle average for that period is not considered to be low, and the remaining capacity estimation based on current integration is not adopted. Continue statutory estimation. Thereafter, when the current cycle average value becomes Ith or less, the remaining capacity of the storage battery 1 estimated by the remaining capacity estimation method based on the cycle average is adopted, and this value is used as the initial value of the remaining capacity of the storage battery 1 in the remaining capacity estimation method based on the current integration. Set to value and continue estimation. When the current cycle average value, which is the average value of the current in the operation cycle, is larger than the specified value Ith, the remaining capacity of the storage battery 1 estimated by the remaining capacity estimation method by current integration is displayed.

  In this way, by combining the remaining capacity estimation method by cycle average, the remaining capacity estimation method by current integration, and the remaining capacity estimation method by open-circuit voltage, by constructing algorithms that take advantage of each remaining capacity estimation method, The remaining capacity of the storage battery 1 can be estimated with high reliability and accuracy, complementing the drawbacks of the remaining capacity estimation methods. Note that an optimum remaining capacity estimation method may be selected by setting conditions such as a remaining capacity value and a length of an operation cycle.

  As described above, it is possible to detect the remaining capacity of the storage battery 1 stably and accurately by combining the remaining capacity estimation method using cycle average, the remaining capacity estimation method using open-circuit voltage, and the remaining capacity estimation method using current integration. A storage battery remaining capacity detection device can be obtained.

Embodiment 4 FIG.
In the first to third embodiments, the case where the remaining capacity estimation method based on the cycle average is mainly used has been described, but in this embodiment, the case where the remaining capacity estimation method based on the cycle average is used as an auxiliary will be described. FIG. 12 is a flowchart showing the operation of the storage battery remaining capacity detection device according to Embodiment 3 of the present invention. First, in step ST201, the initial value of the remaining capacity of the storage battery 1 is set using the remaining capacity estimation method based on the open terminal voltage at the start of operation. The method using the open terminal voltage can measure the remaining capacity of the storage battery 1 most accurately. However, since it cannot be used unless a sufficiently long time has passed with the electrode opened, it is applied at the start of operation. However, since it is not known whether a sufficiently long time has elapsed at the start of operation, if the sufficiently long time has not elapsed, the remaining capacity value of the last storage battery 1 at the previous operation is used as the initial value. Next, in step ST202, the remaining capacity of the storage battery 1 is estimated by a remaining capacity estimation method based on current integration. While the vehicle is traveling, the remaining capacity of the storage battery 1 is always estimated by a remaining capacity estimation method based on current integration.

  In step ST203, it is determined whether the vehicle is stopped. When the vehicle is stopped, in step ST204, the remaining capacity of the storage battery 1 is estimated by the remaining capacity estimation method based on the cycle average. Here, there are the remaining capacity value of the storage battery 1 obtained by the remaining capacity estimation method based on current integration and the remaining capacity value of the storage battery 1 obtained by the remaining capacity estimation method based on cycle average. Here, it is determined which method is highly reliable, and the storage battery 1 is controlled by the internal combustion engine based on the remaining capacity value of the storage battery 1 obtained by the highly reliable method, or in order to prevent overcharge. System control such as shutting off the regenerative current is performed.

  In the remaining capacity estimation method based on current integration, the error in the estimated value may accumulate as the time after the initial setting of the remaining capacity of the storage battery 1 elapses. Therefore, the elapsed time from the start of operation. Thus, the remaining capacity estimation method of the storage battery 1 is determined. In step ST205, when the elapsed time from the start of operation is longer than Tth, it is determined in step ST206 to adopt the remaining capacity estimation method based on cycle averaging. In step ST207, the remaining capacity of the storage battery 1 is updated. If the vehicle is not stopped and if the elapsed time from the start of operation is less than Tth, it is determined in step ST208 that the remaining capacity estimation method based on current integration is adopted. In step ST207, the remaining capacity of the storage battery 1 is updated. After updating the remaining capacity of the storage battery 1, the process returns to step ST105.

  Tth is the time during which the remaining capacity estimation method based on the cycle average increases the estimation accuracy of the remaining capacity of the storage battery 1 compared to the remaining capacity estimation method based on current integration. The remaining capacity estimation method based on current integration has the disadvantage that the error in remaining capacity estimation increases with time. When the time exceeds Tth, this error is the inherent accuracy of the remaining capacity estimation method based on cycle averaging. Exceeds uncertainty. In order to determine this Tth specifically, it is necessary to quantify the magnitude of this error in consideration of the overall system and appropriate conditions. From the experimental results, a value of 2 hours is obtained as Tth.

  In the remaining capacity estimation method based on current integration, it is necessary to obtain the initial value of the remaining capacity of the storage battery 1 by some method. For this reason, for example, a remaining capacity estimation method using an open terminal voltage is used. When applied to a vehicle such as a hybrid vehicle, there is a method in which the remaining capacity of the storage battery 1 is estimated to be an initial value from an open terminal voltage immediately before starting after a long pause such as at night.

  As described above, the remaining capacity estimation method based on current integration is mainly used, and the remaining capacity estimation method based on cycle average is used supplementarily, so that the remaining capacity of the storage battery 1 can be detected stably and accurately. A detection device can be obtained.

Embodiment 5. FIG.
The choice of adopting the remaining capacity estimation method by current integration and the remaining capacity estimation method by cycle average can be determined by the current cycle average value. When the current cycle average value is large, the remaining capacity estimation method by current integration is adopted, and when the current cycle average value is small, the remaining capacity estimation method by cycle average is adopted. FIG. 13 is a flowchart showing the operation of the storage battery remaining capacity detection device according to Embodiment 5 of the present invention. In FIG. 13, step ST201 to step ST205 are the same as in the fourth embodiment. In step ST209, it is determined whether or not the current cycle average value in the remaining capacity estimation method by cycle average is smaller than Ith. When the current cycle average value is smaller than Ith, in step ST206, it is determined to adopt the remaining capacity estimation method of the storage battery 1 by the cycle average. In step ST207, the remaining capacity of the storage battery 1 is updated. About setting of Ith, it sets to the value from which the difference of the change of the average value of the voltage of 1 driving cycle and the change of the voltage when it discharges with a fixed current becomes large. For example, it may be set to 20A as shown in the first embodiment. When the vehicle is not stopped, if the elapsed time from the start of driving is less than tth and the current cycle average value exceeds Ith, the remaining capacity estimation method based on current integration should be adopted in step ST208. decide. In step ST207, the remaining capacity of the storage battery 1 is updated. After updating the remaining capacity of the storage battery 1, the process returns to step ST105.

  As described above, the remaining battery capacity that enables stable and accurate detection of the remaining capacity of the storage battery 1 by mainly using the remaining capacity estimating method based on current integration and supplementarily using the remaining capacity estimating method based on cycle averaging. A detection device can be obtained.

  In all the embodiments, a lead storage battery can be applied as a storage battery for detecting the remaining capacity. The present invention is effective when there is a long time constant in the voltage change after charging or discharging, which is a feature common to general storage batteries. Therefore, you may apply to storage batteries, such as a lithium ion battery, a nickel cadmium battery, and a nickel metal hydride battery.

It is a block diagram of the storage battery residual capacity detection apparatus which shows Embodiment 1 of this invention. It is a figure which shows the relationship between the speed relevant to driving | running | working of the hybrid vehicle in Embodiment 1 of this invention, and DC current which flows into a storage battery. It is a figure which shows the relationship between the DC current which flows into the storage battery of the hybrid vehicle in Embodiment 1 of this invention, and the terminal voltage of a storage battery. It is a figure which shows the time change of the terminal voltage with respect to the remaining capacity of the storage battery in the state in a discharge state on the average in Embodiment 1 of this invention. It is a figure which shows the time change of the terminal voltage with respect to the remaining capacity of the storage battery in the state of charge in the average in Embodiment 1 of this invention. It is a figure which shows the relationship between the voltage acquired previously in Embodiment 1 of this invention, and an electric current. It is a figure which shows the time change of the terminal voltage with respect to the remaining capacity of the storage battery in the state in a discharge state on the average in Embodiment 1 of this invention. It is a figure which shows the measurement result of the standard deviation in Embodiment 1 of this invention. It is a block diagram of the storage battery remaining capacity detection apparatus which shows Embodiment 2 of this invention. It is a flowchart which shows operation | movement of the storage battery residual capacity detection apparatus in Embodiment 2 of this invention. It is a flowchart which shows operation | movement of the storage battery residual capacity detection apparatus in Embodiment 3 of this invention. It is a flowchart which shows operation | movement of the storage battery residual capacity detection apparatus in Embodiment 4 of this invention. It is a flowchart which shows operation | movement of the storage battery residual capacity detection apparatus in Embodiment 5 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Storage battery 2 Load 3 Voltage detection part 4 Current detection part 5 Average value calculation part 6 Characteristic data storage part 7 Average remaining capacity estimation part 8 Accumulated remaining capacity estimation part 9 OCV remaining capacity estimation part 10 System control unit, 11, 12 Storage battery remaining capacity detection device.

Claims (8)

Voltage detection means for measuring the voltage of the storage battery;
Current detection means for measuring a current flowing through the storage battery;
An average value calculating means for calculating an average value of the voltage and an average value of the current for a predetermined time;
Characteristic data storage means for storing the relationship between the voltage and current acquired in advance;
Storage battery remaining capacity detection comprising: an average remaining capacity estimating means for estimating a remaining battery capacity from the relationship between the average value of the voltage and the average value of the current and the relationship between the voltage and the current acquired in advance. apparatus. The storage battery residual capacity detection according to claim 1, wherein the storage battery repeatedly performs a charge / discharge pattern including charging and discharging, and performs the charge / discharge pattern at least once within a predetermined time for calculating an average value. apparatus. 3. The storage battery remaining capacity detection device according to claim 1, further comprising integrated remaining capacity estimation means for estimating a storage battery remaining capacity from time integration of a current flowing through the storage battery. 4. The storage battery remaining capacity detecting device according to claim 3, wherein when the average value of the current is larger than a specified value, the remaining battery capacity estimated by the integrated remaining capacity estimating means is displayed. 5. The storage battery remaining capacity detection device according to claim 1, wherein the storage battery remaining capacity detection device is mounted on a vehicle including an electric motor that converts electric power of the storage battery into motive power, generates electric power with braking force, and stores the electric power. 6. The storage battery remaining capacity detection device according to claim 5, wherein the vehicle is a hybrid vehicle including an internal combustion engine. 7. The storage battery remaining capacity detection device according to claim 5, wherein a series of operations of starting, accelerating, decelerating, and stopping the vehicle is performed at least once in a charge / discharge pattern. The vehicle detects the remaining battery capacity based on the open terminal voltage when leaving the vehicle, and estimates the remaining battery capacity by time integration of the current value using the detected value as an initial value. The storage battery residual capacity detection apparatus in any one of.

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