JP2004042799A - Battery residual capacity estimating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery residual capacity estimating method for estimating the residual capacity of a battery with high accuracy. <P>SOLUTION: The open circuit voltage of a lead battery when an IGN switch is on is measured to calculate the residual capacity Q<SB>OCV</SB>of the lead battery, the internal resistance r of the lead battery is calculated from the change of the current and the voltage when an engine is started and the residual capacity Q<SB>r</SB>of the lead battery is calculated, and the residual capacity Q<SB>int</SB>of the lead battery is calculated from the average value of the residual capacity Q<SB>OCV</SB>and the residual capacity Q<SB>r</SB>(S104). The residual capacity Q<SB>res</SB>is corrected by integrating the charge and discharge current running in the lead battery before the engine is re-started (S106). The internal resistance r of the lead battery is calculated from the change in the current and the voltage when the engine is re-started, and the residual capacity Q<SB>C</SB>of the lead battery is calculated (S134). The residual capacity Q<SB>res</SB>is corrected to the residual capacity Q<SB>C</SB>(S136). Respective characteristics of the open circuit voltage and the internal resistance when the engine is started are reflected in the residual capacity Q<SB>int</SB>, and accumulation of errors for each re-start of the engine is prevented. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for estimating a remaining battery charge, and in particular, relates to a method of calculating a remaining charge of a battery mounted on a vehicle having an idle stop / start function by calculating an internal resistance of the battery when the engine is started and an integrated current flowing through the battery. The present invention relates to a remaining battery capacity estimating method for estimating a remaining capacity by a combination.
[0002]
[Prior art]
Conventionally, batteries such as lead batteries mounted on vehicles are float-charged by an alternator during traveling and the load is limited to lamps, etc., so they are not deeply discharged and are almost always kept near a fully charged state It had been. However, in recent years, due to increasing environmental awareness, it has become necessary to reduce the emission of carbon dioxide gas from vehicles. Particularly, vehicles such as large buses and trucks have an idle stop function that stops the engine when stopping at signal waiting times. System vehicles are increasing.
[0003]
In a system vehicle having an idle stop function, loads such as an air conditioner and a car stereo while the engine is stopped are all covered by electric power from a battery. For this reason, deep discharge of the battery is increased as compared with the related art, and an increase in a case where the remaining capacity of the battery is reduced is expected. Since the output of the battery depends on the remaining capacity of the battery, if the remaining capacity of the battery decreases while the engine is stopped, a sufficient output for starting the engine cannot be obtained, and the engine is restarted (idle stop start, ISS) after the engine is stopped. May not be possible. Therefore, in order to maintain the ISS-capable state, the remaining capacity of the battery is estimated to monitor the presence or absence of the output necessary for starting the engine. If there is no required output, it is necessary to send a signal such as stopping the idle stop and charging the battery to the computer on the vehicle side.
[0004]
On the other hand, as a method of estimating the remaining capacity of a battery, a method of adding an integrated value of a charge / discharge current to an initial state of charge (SOC) of the battery is known. Also, for example, Japanese Patent Application Laid-Open Nos. 6-59003 and 9-96665 describe a current-voltage characteristic measured from a current and a voltage waveform of a battery mounted on an electric vehicle or the like, and a battery characteristic in advance. A method has been proposed for estimating the remaining capacity of the battery by comparing the remaining capacity of the battery created by measurement and the relationship of the current-voltage characteristic table.
[0005]
[Problems to be solved by the invention]
However, in the technique disclosed in the above publication, since there is no process for correcting the error in the amount of charge / discharge electricity, the integration error of the charge / discharge current is accumulated, and the self-discharge (from parking to start of the engine) when the battery is not used. It is difficult to accurately estimate the remaining capacity of the battery due to the change in the remaining capacity of the battery due to the above. Also in the method using the current-voltage characteristic table, it is difficult to accurately estimate the remaining capacity due to the change in voltage due to the history of the battery.
[0006]
The present invention has been made in view of the above circumstances, and has as its object to provide a battery remaining capacity estimation method capable of accurately estimating a remaining battery capacity.
[0007]
[Means for Solving the Problems]
In order to solve the above-described problem, a first aspect of the present invention provides an internal resistance of the battery which is calculated at the time of engine start by calculating a remaining capacity of a battery mounted on a vehicle having an idle stop / start function. A battery remaining capacity estimating method for estimating the remaining battery charge based on a combination of a flowing integrated current and a battery remaining capacity estimation method based on a relationship between a predetermined remaining battery capacity and a predetermined open circuit voltage by measuring an open circuit voltage of the battery at key-on. Q_OCVIs calculated, and the internal resistance of the battery is calculated from the current and voltage changes at the time of starting the engine, and the remaining capacity Q of the battery is calculated from the relationship between the predetermined remaining capacity and the internal resistance of the battery._rAnd the remaining capacity Q_OCVAnd remaining capacity Q_rFrom the average value of_intAnd the internal resistance of the battery is calculated from changes in current and voltage when the engine is restarted, and the remaining capacity Q of the battery is calculated from the relationship between the remaining capacity and the internal resistance of the battery._CAnd the charge / discharge current flowing to the battery before restarting the engine is calculated as the remaining capacity Q_intOr remaining capacity Q_CRemaining capacity Q corrected by integrating_resIs the remaining capacity Q_CTo include the steps.
[0008]
In this embodiment, the remaining battery charge Q at the time of key-on_OCVAnd the remaining battery charge Q at the start of the engine_rFrom the average value of the remaining battery capacity Q_intIs calculated, and the respective characteristics of the open circuit voltage and the internal resistance are changed to the remaining capacity Q._intAt the start of the engine,_intAccuracy can be improved, and the corrected remaining capacity Q every time the engine is restarted._resIs the remaining capacity Q_CAnd the accumulation of errors is prevented, so that the remaining capacity of the battery can be calculated with high accuracy.
[0009]
According to a second aspect of the present invention, a remaining capacity of a battery mounted on a vehicle having an idle stop / start function is estimated by a combination of an internal resistance of the battery calculated at the time of engine start and an integrated current flowing through the battery. A battery remaining capacity estimating method for measuring the open circuit voltage of the battery at the time of key-on, and determining the remaining battery capacity Q of the battery from a predetermined relationship between the remaining battery capacity and the open circuit voltage._OCVAnd the internal resistance of the battery is calculated from the current and voltage changes at the time of engine restart, and the remaining capacity Q of the battery is calculated from a predetermined relationship between the remaining capacity of the battery and the internal resistance._CAnd the charge / discharge current flowing to the battery before restarting the engine is calculated as the remaining capacity Q_OCVOr remaining capacity Q_CRemaining capacity Q corrected by integrating_resIs the remaining capacity Q_CTo include the steps.
[0010]
In the first and second aspects, if the measured open circuit voltage of the battery is corrected to the open circuit voltage at a predetermined temperature from the relationship between the predetermined battery temperature and open circuit voltage, the temperature dependency of the open circuit voltage of the battery can be reduced. Since it can be excluded, the remaining capacity of the battery can be calculated with higher accuracy. Before starting the engine, the remaining capacity Q_OCVIs the minimum remaining capacity Q that allows the battery to start the engine._minThe method may further include a step of determining that the engine can be started when it is larger.
[0011]
According to a third aspect of the present invention, a remaining capacity of a battery mounted on a vehicle having an idle stop / start function is estimated by a combination of an internal resistance of the battery calculated at the time of starting the engine and an integrated current flowing through the battery. A battery remaining capacity estimating method, wherein an internal resistance of the battery is calculated from a current and a voltage change at the time of starting the engine, and a remaining capacity of the battery is calculated based on a predetermined relationship between the remaining battery capacity and the internal resistance._intAnd the internal resistance of the battery is calculated from changes in current and voltage when the engine is restarted, and the remaining capacity Q of the battery is calculated from the relationship between the remaining capacity and the internal resistance of the battery._CAnd the charge / discharge current flowing to the battery before restarting the engine is calculated as the remaining capacity Q_intOr remaining capacity Q_CRemaining capacity Q corrected by integrating_resIs the remaining capacity Q_CTo include the steps.
[0012]
In the first to third aspects, the internal resistance is the battery voltage before the engine is started or before the engine is restarted and the battery voltage after a predetermined time has elapsed after the start of the engine start current or after the start of the engine restart current. Is divided by the current difference between the battery current before the engine start or before the engine restart and the battery current after a predetermined time has elapsed after the start of the engine start current or after the start of the engine restart current. It is preferable to obtain it. Further, if the predetermined time exceeds 50 ms from the start of energization of the engine start current or the start of energization of the engine restart current, the error in the current and voltage flowing to the battery increases. More preferably, it is within 50 ms from the start of energization of the starting current. Furthermore, by measuring the temperature of the battery and correcting the calculated internal resistance of the battery to the internal resistance at a predetermined temperature from the relationship between the predetermined battery temperature and the internal resistance correction value, the temperature dependence of the internal resistance of the battery can be obtained. Can be eliminated, so that the remaining capacity of the battery can be calculated with higher accuracy. Further, before the engine restarts, the corrected remaining capacity Q_resIs the minimum remaining capacity Q that allows the battery to start the engine._minIt may further include a step of determining that the engine can be restarted when it is larger. Furthermore, the minimum remaining capacity Q_minIs determined from the relationship between the remaining capacity of the battery and the internal resistance in accordance with the predetermined maximum internal resistance that allows the battery to start the engine from the minimum voltage value and the required current value determined from the characteristics of the engine starter. Is set and the remaining correction capacity Q_resIs the minimum remaining capacity_minWhen it is smaller than the above, it may be determined that the engine cannot be restarted.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
(1st Embodiment)
Hereinafter, an embodiment in which the present invention is applied to a battery state detection system will be described with reference to the drawings.
[0014]
(Constitution)
As shown in FIG. 1, the battery state detection system 10 of the present embodiment detects or calculates the internal resistance r, open circuit voltage (OCV), discharge voltage, and the like of the lead battery 1 and detects the battery state of the lead battery 1. And functions as a lower system of a vehicle control system that controls a vehicle such as an engine. The battery state detection system 10 functions as a CPU that functions as a central processing unit, a ROM in which a basic control program of the battery state detection system 10 and various setting values are stored as described later, and serves as a work area for the CPU. It is configured to include a RAM for temporarily storing data, an A / D converter, an interface for communicating with the vehicle control system 11, a bus for connecting these, and the like.
[0015]
The lead battery 1 has a rectangular battery case serving as a container, and the material of the battery case is excellent in moldability, electrical insulation, corrosion resistance, durability, and the like. For example, acrylic butadiene styrene (ABS) ), Polypropylene (PP), and polyethylene (PE). A sensor insertion hole is formed in a central partition wall of the battery case. A temperature sensor 2 such as a thermistor is inserted into the sensor insertion hole, and the temperature sensor 2 is fixed in the sensor insertion hole with an adhesive.
[0016]
In addition, the battery case of the lead battery 1 is defined as a monoblock battery case integrally formed by, for example, a total of 18 cell chambers arranged in two rows and nine columns by partitions partitioning the inside of the outer peripheral wall vertically and horizontally. . One set of electrode plates (cells) is accommodated in each cell chamber in the battery case, and a total of 18 electrode plate groups are housed in the entire battery case. In each electrode plate group, six unformed negative electrode plates and five unformed positive electrode plates are laminated via a retainer (separator) made of glass fiber, and the nominal voltage (cell voltage) after formation (first charge) is 2.0V. Therefore, the group voltage of the lead battery 1 is 36V.
[0017]
The upper part of the battery case is adhered (or welded) to an upper lid made of a polymer resin such as ABS which seals the upper opening of the battery case. A control valve for controlling the internal pressure of each cell chamber to a predetermined value or less is provided at a position corresponding to the center of each cell chamber at the upper lid, and a lead battery 1 is used at a diagonal corner as an external power source using a lead battery 1 as a power supply. A rod-shaped positive external output terminal and a negative external output terminal for supplying power to the battery are provided upright.
[0018]
The positive electrode external output terminal of the lead battery 1 is connected to a center terminal of an ignition switch (hereinafter, referred to as an IGN switch) 5. The IGN switch 5 has an OFF terminal, an ON / ACC terminal, and a START terminal separately from the center terminal, and the center terminal and any of these OFF, ON / ACC, and START terminals are switched by rotary switching. It is possible. On the other hand, a negative electrode external output terminal of the lead battery 1 is connected to the ground via a current sensor 4 such as a Hall element. The current sensor 4 can detect a current by a Hall voltage that changes according to a current flowing through the Hall element.
[0019]
The positive and negative external output terminals of the lead battery 1, both end terminals of the temperature sensor 2, and the output terminal of the current sensor 4 are connected to an A / D converter in the battery state detection system 10. For this reason, the CPU of the battery state detection system 10 can take in the voltage, current, and temperature of the lead battery 1 as digital values.
[0020]
The ON / ACC terminal of the IGN switch 5 is connected to one end of an auxiliary device 6 such as a lamp, a wiper, a radio, etc., and is connected to a regulator RG and a rectifying element D that allows a current to flow in one direction. Is connected to one end of a generator (alternator) 7 that generates electric power by the rotational driving force. The rectifying element D has an anode connected to one end of the generator 7 and a cathode connected to the regulator RG. The START terminal of the IGN switch 5 is connected to one end of the starter 9 for starting the engine.
[0021]
A gear pulley or an endless belt (not shown) for transmitting the torque of the starter 9 to the engine 8 is interposed between the rotation axis of the starter 9 and the rotation axis of the engine 8. An electric clutch for transmitting the rotational driving force of the engine 8 to the generator 7 is interposed between the rotating shaft and the rotating shaft. Therefore, when the engine 8 is operating, the electric clutch between the engine 8 and the generator 7 is connected to transmit the rotational driving force of the engine 8 to the generator 7. When the IGN switch 5 is in the ON / ACC position and the generator 7 is operating, the lead battery 1 has a remaining capacity Q calculated by the battery state detection system 10._resAlternatively, the battery is charged according to the state of charge (SOC).
[0022]
The vehicle control system 11 includes a CPU, a ROM, a RAM, an engine control unit that controls the engine 8, a clutch control unit that controls an electric clutch, an interface, and the like. The control unit is connected to the electric clutch. The vehicle control system 11 is connected to the battery state detection system 10 via a communication line, and the two can communicate with each other. The accessory 6, the generator 7, the other end of the starter 9, the battery state detection system 10, and the vehicle control system 11 are connected to the ground. Note that the OFF terminal of the IGN switch 5 is not connected to any of them.
[0023]
(motion)
Next, an operation of the battery state detection system 10 of the present embodiment will be described with reference to a flowchart. When the battery state detection system 10 is turned on, the set values and the like stored in the ROM are expanded in the RAM in the initial setting process, and the battery state detection routine shown in FIG. 2 is executed.
[0024]
In the battery state detection routine, first, in step 102, a current value flowing through the current sensor 4 is taken in, and integration (current integration) of the amount of electricity (Ah) input / output to / from the lead battery 1 is started. Next, at step 104, the initial remaining capacity Q of the lead battery 1 is calculated._intIs executed, the initial remaining capacity calculation processing subroutine for estimating the remaining capacity is executed.
[0025]
As shown in FIG. 3, in the initial remaining capacity calculation processing subroutine, in step 202, the process waits until there is a notification from the vehicle control system 11 that the IGN switch 5 is located at the ON position. The open circuit voltage (OCV) and the temperature (T) of the lead battery 1 are captured. In step 206, the open circuit voltage taken in step 204 is temperature corrected to an open circuit voltage at a temperature of 25 ° C., and the remaining capacity Q of the lead battery 1 is calculated from the temperature corrected open circuit voltage._OCVIs estimated. That is, as shown in FIG. 6, an OCV-T correction value map is developed in the RAM. For example, when the temperature of the lead battery 1 is 10 ° C., the open-circuit voltage correction value is 0 ° C. Calculated as (25−10) × 0.05 / 25 = 0.03 (V) by proportional calculation from the circuit voltage correction value 0.05 (V) and the open circuit voltage correction value 0 (V) at 25 ° C. Is done. The open circuit voltage after the temperature correction is obtained by adding a correction value (0.03 (V)) to the open circuit voltage taken in step 204. Then, in step 208, as shown in FIG._resRemaining capacity Q of lead battery 1 corresponding to open circuit voltage after temperature correction on map_OCVIs obtained using a proportional calculation or the like.
[0026]
Next, in step 210, the remaining capacity Q acquired in step 208_OCVThe minimum remaining capacity Q that allows the engine to start determined by the specifications (characteristics) of the starter 9 and the like._minIt is determined whether or not the engine can be started by determining whether or not is smaller (see FIG. 9).
[0027]
Such a minimum remaining capacity Q_minAre loaded on the RAM in the initial setting process. Minimum voltage value V that allows engine start_minAnd required current value I_reqIs determined from the specifications (characteristics) of the starter 9 and the like, and the open circuit voltage OCV and the minimum voltage value V_min, Required current value I_reqAnd the maximum internal resistance value r of the lead battery 1 that allows the engine to start_maxBetween the minimum voltage value V_min= Open circuit voltage OCV-maximum internal resistance value r_max× Requested current value I_reqThere is a relationship. Maximum internal resistance value r set using this relationship_maxHas a meaning of a limit value at which the lead battery 1 allows the engine to start, and the internal resistance r of the lead battery 1 is the maximum internal resistance r._maxIf it is larger, the engine cannot be started. Also, the remaining capacity Q of the lead battery 1_resFrom the relationship between the internal resistance r and the maximum internal resistance r_maxRemaining capacity Q of the lead battery 1 corresponding to_minIs also set (see FIG. 9).
[0028]
If an affirmative determination is made in step 210, the next step 212 notifies the vehicle control system 11 that the engine can be started. If a negative determination is made, the vehicle control system 11 notifies the vehicle control system 11 in step 214 that the engine cannot be started. Then, the process returns to step 202. When the CPU of the vehicle control system 11 receives a notification from the battery state detection system 10 that the engine cannot be started, for example, it turns on a battery lamp indicating that external charging of the lead battery 1 is required.
[0029]
In the next step 216, the current value and the voltage value flowing through the lead battery 1 are fetched, and in step 218, the remaining capacity Q estimated in step 208_OCVTo the remaining capacity Q_OCVIs corrected.
[0030]
Next, at step 220, it is determined whether or not the IGN switch 5 has been moved from the ON position to the START position based on whether or not the value of the current flowing through the current sensor 4 exceeds a predetermined value (for example, 0.1 A). As shown in FIG. 4, the current waveform of the lead battery 1 at the time of starting the engine is such that when the IGN switch 5 is located at the START position, the engine starting current is supplied (at time t)._s), A rapid first-stage pulse discharge to the starter 9 is performed, and when about 50 ms has elapsed (time t_p) Shows the first peak. After that, the engine start is completed through several peaks that attenuate. The current waveform is affected by the structure of the engine 8, the friction of the belt and the gear pulley connecting the engine 8 and the starter 9, and the like, and generally has a waveform as shown in FIG.
[0031]
In the next step 222, at the start of energization of the engine starting current (at time t_s), Wait until a predetermined time (for example, 50 ms) elapses. In step 224, the current (starting current) at the time of the first-stage pulse discharge, the voltage and the temperature of the lead battery 1 are captured. Next, in step 226, the (actually measured) internal resistance r is calculated using the voltage and current actually measured in step 224. That is, the voltage difference ΔV between the open circuit voltage (OCV) of the lead battery 1 before the engine, which is taken in step 216 and whose temperature is corrected, and the voltage at the time of starting the engine, which is taken in step 224 and whose temperature is corrected, is taken in step 216. The absolute value of the internal resistance r (= voltage difference ΔV / current difference ΔI) divided by the current difference ΔI between the current value before starting the engine and the current value at the time of starting the engine taken in step 224 is calculated. Next, at step 228, the internal resistance r calculated at step 226 is temperature-corrected to the internal resistance at a temperature of 25 ° C. At step 230, the remaining capacity Q of the lead battery 1 is calculated from the temperature-corrected internal resistance r._rIs estimated. In the next step 232, the remaining capacity Q estimated in step 208_OCVAnd the remaining capacity Q estimated in step 230_rAnd the initial remaining capacity Q of the lead battery 1_intIs estimated (Q_int= 1/2 (Q_OCV+ Q_r)), End the initial remaining capacity calculation processing subroutine, and proceed to step 106 in FIG.
[0032]
In step 106, the charge / discharge current flowing through the lead battery 1 is calculated as the remaining capacity Q estimated in step 232._intTo the remaining capacity Q_resIs corrected, and in the next step 108, the remaining capacity Q_resIs the minimum remaining capacity Q_minIt is determined whether the engine can be started, that is, whether or not idle stop (IS) is possible by determining whether or not it is larger (see FIG. 9). If the determination is affirmative, the vehicle control system 11 is notified in step 110 that the idle stop is possible, and if the determination is negative, the vehicle control system 11 is notified in step 112 that the idle stop is not possible. Return to step 106. The CPU of the vehicle control system 11 stops the driving of the engine 8 via the engine control unit when the vehicle speed becomes 0 while receiving the notification that the idle stop is possible, and enters the idle stop state. The battery state detection system 10 is notified of the fact. On the other hand, when the CPU of the vehicle control system 11 receives the notification from the battery state detection system 10 that the idle stop cannot be performed, the engine 8 cannot be restarted after the idle stop, so that the vehicle speed becomes zero. Also causes the engine 8 to continue driving.
[0033]
Next, in step 114, it is determined whether or not a notification that the vehicle has entered the idle stop state has been received from the vehicle control system 11. If the determination is negative, the process returns to step 106; , The remaining capacity Q obtained by correcting the integrated quantity of electricity in step 106_resTo the remaining capacity Q_resIs re-corrected.
[0034]
Next, at step 118, the remaining capacity Q estimated at step 116_resIs the minimum remaining capacity Q_minBy judging whether or not it is larger than it is determined whether or not the idle stop can be continued, that is, whether or not the engine can be started (see FIG. 9). If a negative determination is made, at step 122, the vehicle control system 11 is notified that the engine 8 needs to be started, and the routine proceeds to step 126. The CPU of the vehicle control system 11 having received the notification controls the engine control unit and the clutch control unit to start the engine 8 and transmits the rotational driving force to the generator 7. Thereby, the lead battery 1 is charged, and as a result, the remaining capacity Q_resIs the minimum remaining capacity Q_minBe larger.
[0035]
On the other hand, if an affirmative determination is made in step 118, the current and voltage are fetched in step 120, and in the next step 124, it is determined whether or not the IGN start 5 is located at the START position as in step 220, and a negative determination is made. Returns to step 116, and when the determination is affirmative, the remaining capacity Q of the lead battery 1 is determined in steps 126 to 134 as in steps 222 to 230._CIs estimated. In the next step 136, the remaining capacity Q corrected in step 106 or step 116_resIs the remaining capacity Q estimated in step 134_CAnd the process returns to step 106.
[0036]
Thereafter, before the engine restarts, the charge / discharge current flowing through the lead battery 1 is changed to the remaining capacity Q._CTo the remaining capacity Q_resIs corrected, and it is determined in step 118 whether or not the engine can be restarted. When the determination is affirmative, the remaining capacity Q of the lead battery 1 at the time of engine startup is determined._CAnd the remaining capacity Q corrected in step 106 every time the engine is started._resIs the remaining capacity Q_CTo correct (reset) (see FIG. 5).
[0037]
(Action, etc.)
Next, the operation of the battery state detection system 10 of the present embodiment will be described.
[0038]
The battery state detection system 10 according to the present embodiment is configured such that the remaining capacity Q of the lead battery 1 when the IGN switch 5 is turned on._OCV(Step 208, etc.), and the remaining capacity Q of the lead battery 1 is_r(Step 230 etc.) and the remaining capacity Q_{OC V}And remaining capacity Q_rFrom the average value of the initial remaining capacity Q of the lead battery 1_intIs calculated (step 232). Therefore, the respective characteristics (OCV-Q) of the open circuit voltage and the internal resistance of the lead battery 1_resMap and rQ_resMap) is the initial remaining capacity Q_intAt the time of starting the engine, the initial remaining capacity Q_intAccuracy can be improved.
[0039]
Further, the battery state detection system 10 of the present embodiment is configured such that the corrected remaining capacity Q_res(Step 106) is replaced with remaining capacity Q_C(Step 136), the accumulation of measurement errors of the current sensor 4 can be prevented, and the remaining capacity Q of the lead battery 1 can be accurately determined._resCan be calculated. Therefore, according to the battery state detection system 10 of the present embodiment, since the battery state of the lead battery 1 is detected with high accuracy, the restart of the engine 8 can be ensured even when the engine 8 is stopped at the time of idle stop / start. Further, it is possible to grasp in advance whether the idle stop is possible before the engine 8 is stopped. Therefore, the vehicle control system 11 can receive the notification from the battery state detection system 10 of the lower system, and can control the stop / restart (idle stop / start) of the engine 8 to reduce the exhaust gas while the vehicle is stopped. Can contribute.
[0040]
Furthermore, in the battery state detection system 10 of the present embodiment, the current (discharge) waveform at the time of engine start has reproducibility, and in a vehicle having an idle stop / start function, the engine restart is repeated and the number of resets is large. So, every time the engine starts, the remaining capacity Q_CCan be estimated.
[0041]
Further, in the battery state detection system 10 of the present embodiment, by using the lead battery 1 as the battery, the open circuit voltage OCV and the remaining capacity Q of the lead battery 1 are_res(See FIG. 7), internal resistance value r and remaining capacity Q_res(See FIG. 9), a high correlation is obtained, and even if a coarse map is used, the remaining capacity Q of the lead battery 1 can be accurately determined._resAnd the start of the engine can be determined.
[0042]
Furthermore, in the battery state detection system 10 of the present embodiment, the temperature T of the lead battery 1 is measured, and the temperature of the open circuit voltage OCV of the lead battery 1 is corrected from the OCV-T correction map of the lead battery 1 (see FIG. 6), the remaining capacity Q of the lead battery 1 depending on the temperature._resCan be calculated without temperature dependence, and the number of maps created can be reduced.
[0043]
Further, in the battery state detection system 10 of the present embodiment, the remaining capacity Q_OCVIs the minimum remaining capacity Q that allows the lead-acid battery 1 to start the engine_minWhen it is larger, it is determined that the engine can be started, so that it is possible to notify the vehicle control system 11 of whether or not the engine can be started.
[0044]
In addition, in the battery state detection system 10 of the present embodiment, when calculating the internal resistance r of the lead battery 1 at the time of starting the engine or restarting the engine, the current before starting the engine or before restarting the engine and the start of energizing the engine starting current are started. Since the internal resistance r is calculated from the current value and the voltage value of the first stage within 50 ms after or after the start of the re-current supply of the engine, the charge and discharge of the lead battery 1 are eliminated by eliminating the attenuated portion of the current waveform having a large measurement error. Remaining capacity Q of lead battery 1 regardless of the influence of polarization_resCan be estimated.
[0045]
Furthermore, in the battery state detection system 10 of the present embodiment, the temperature T of the lead battery 1 was measured, and the temperature of the internal resistance r of the lead battery 1 was corrected from the r-T correction value map of the lead battery 1 (FIG. 8). ), The remaining capacity Q of the lead battery 1 by eliminating the temperature dependency._resCan be calculated.
[0046]
Further, in the battery state detection system 10 of the present embodiment, the corrected remaining capacity Q_resIs the minimum remaining capacity Q that allows the lead-acid battery 1 to start the engine_minSince it is determined that the engine can be restarted when it is greater than the above, it is possible to notify the vehicle-side control system 11 of whether or not the engine can be restarted.
[0047]
In the battery state detection system 10 of the present embodiment, the minimum voltage value and the required current value are determined from the characteristics of the starter 9 for starting the engine._minIs set based on the relationship between the remaining capacity and the internal resistance of the lead battery 1 corresponding to the maximum internal resistance that allows the engine start of the lead battery 1 predetermined from the minimum voltage value and the required current value. Remaining capacity Q_resIs the minimum remaining capacity_minWhen the engine restart is not possible, the lead battery 1 is charged from the generator 7 before the engine is stopped. Engine start can be ensured.
[0048]
In the present embodiment, an example is described in which the open circuit voltage OCV before the engine is started is taken in when the IGN switch is located at the ON position. , The open circuit voltage OCV may be taken in. In this way, the remaining capacity Q of the lead battery 1 can be more accurately determined from the open circuit voltage OCV of the lead battery 1 having a small measurement error._resCan be calculated (estimated).
[0049]
In this embodiment, the lead battery 1 is exemplified as a battery mounted on a vehicle having an ISS function. However, for example, the lead battery 1 and a lithium ion secondary battery are connected in parallel, You may apply to the hybrid battery which connected the battery in parallel.
[0050]
Further, in the present embodiment, an example is shown in which the temperature T of the lead battery 1 is measured every time the engine is started. However, since the temperature T does not greatly change in a short time, the temperature T is changed every predetermined time (for example, every 10 minutes). T may be measured. By doing so, the calculation load of the battery state detection system 10 can be reduced.
[0051]
Further, in the present embodiment, the starter 9 for starting the engine 8 is exemplified. However, since the lead battery 1 has a group voltage of 36 V (since it constitutes a 42 V system), the motor drive is performed to start the vehicle after the idle stop. It can be used. Therefore, instead of the starter 9 and the generator 7 of FIG. 1, a motor generator 12 having a motor function and a generator (generator) function may be used as shown in FIG. In such a vehicle system, the START terminal of the IGN switch may be connected to one end of the motor generator 12, and the motor generator 12 may be controlled by the motor generator control unit in the vehicle control system 11. According to this vehicle system, since the vehicle can be started by the motor function of the motor generator 12, it is possible to prevent generation of exhaust gas generated at the time of idling stop / start.
[0052]
Further, in the present embodiment, the lead battery 1 having a group voltage of 36 V has been exemplified. However, the present invention is not limited to this, and for example, a battery of a 12 V lead battery generally used in a vehicle at present. You may make it apply to the battery state detection system which detects a state.
[0053]
Further, in the present embodiment, the lead battery 1 has been described as an example in which the distance between the cell chambers is short and the monoblock battery case having the small resistance of the conductive member that connects the cell chambers in series is used. By considering the deterioration, it is possible to detect the battery state of the entire lead battery 1 with higher accuracy.
[0054]
Furthermore, in the present embodiment, an example has been described in which the fact that the IGN switch has been turned to the ON position is received from the vehicle control system 11 in step 202. However, without receiving a notification from the vehicle control system 11, the current sensor 4 Even when the current is detected and the range is within a predetermined range (for example, 0.05 A to 0.1 A), the battery state detection system 10 may independently determine that the IGN switch is located at the ON position. Good.
[0055]
Further, in the present embodiment, an example has been described in which the possible notification is output to the vehicle control system 11 when the IS is possible, and the disable notification is output to the vehicle control system 11 when the IS is not possible. An alarm may be issued.
[0056]
(2nd Embodiment)
Next, a second embodiment in which the present invention is applied to a battery state detection system will be described. The battery state detection system according to the present embodiment uses the initial remaining capacity Q of the lead battery 1._intIs the remaining capacity Q when the IGN switch is ON._OCVWhat you get from In the embodiments after this embodiment, the same components and steps as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted. Only different points will be described.
[0057]
In the present embodiment, as shown in FIG. 11, in the initial remaining capacity calculation processing subroutine, steps 216 to 232 shown in FIG. 3 are omitted. In the initial remaining capacity calculation processing subroutine of the present embodiment, the OCV-Q_resThe remaining capacity estimated from the map is the initial remaining capacity Q_intAnd
[0058]
In the battery state detection system of the present embodiment, the OCV-Q_resInitial remaining capacity Q from map only_intIn the lead battery 1, the open circuit voltage (OCV) and the remaining capacity Q are calculated._resAnd the remaining capacity Q_resCan be accurately estimated, and the number of steps can be reduced as compared with the above-described first embodiment.
[0059]
(Third embodiment)
Next, a third embodiment in which the present invention is applied to a battery state detection system will be described. The battery state detection system according to the present embodiment uses the initial remaining capacity Q of the lead battery 1._intIs the remaining capacity Q calculated from the internal resistance r when the engine is started._rIs what you get.
[0060]
In the present embodiment, as shown in FIG. 12, in the initial remaining capacity calculation processing subroutine, step 232 shown in FIG. 3 is omitted. In the initial remaining capacity calculation processing subroutine of this embodiment, the remaining capacity estimated from the internal resistance r calculated from the current and voltage changes at the time of starting the engine in step 230 is calculated as the initial remaining capacity Q._intAnd
[0061]
In the battery state detection system of the present embodiment, r−Q_resInitial remaining capacity Q from map only_intIn the lead battery 1, the internal resistance r and the remaining capacity Q are calculated._resAnd the remaining capacity Q_resCan be accurately estimated, and the number of steps can be reduced as in the second embodiment.
[0062]
【The invention's effect】
As described above, according to the present invention, the remaining battery charge Q at the time of key-on_OCVAnd the remaining battery charge Q at the start of the engine_rFrom the average value of the remaining battery capacity Q_intIs calculated, and the respective characteristics of the open circuit voltage and the internal resistance are changed to the remaining capacity Q._intAt the start of the engine,_intAccuracy can be improved, and the corrected remaining capacity Q every time the engine is restarted._resIs the remaining capacity Q_CSince the error is prevented from being accumulated, the remaining battery capacity can be calculated with high accuracy.
[Brief description of the drawings]
FIG. 1 is a block circuit diagram of a vehicle system including a battery state detection system according to an embodiment to which the present invention can be applied.
FIG. 2 is a flowchart illustrating a battery state detection routine of the battery state detection system according to the first embodiment.
FIG. 3 is a flowchart of an initial remaining capacity calculation processing subroutine showing details of step 104 of a battery state detection routine.
FIG. 4 is a graph showing a current waveform of a lead battery when the engine is started.
FIG. 5 is a graph schematically showing a charge / discharge pattern of a lead battery.
FIG. 6 is a graph showing a relationship between a lead battery temperature and an open circuit voltage correction value.
FIG. 7 is a graph showing a relationship between a remaining capacity of a lead battery and an open circuit voltage.
FIG. 8 is a graph showing a relationship between a lead battery temperature and an internal resistance correction value.
FIG. 9 is a graph showing the relationship between the remaining capacity and the internal resistance of a lead battery.
FIG. 10 is a block circuit diagram of another vehicle system including a battery state detection system according to an embodiment to which the present invention can be applied.
FIG. 11 is a flowchart showing details of an initial remaining capacity calculation processing subroutine showing details of step 104 of the battery state detection routine of the second embodiment.
FIG. 12 is a flowchart showing details of an initial remaining capacity calculation processing subroutine showing details of step 104 of the battery state detection routine of the third embodiment.
[Explanation of symbols]
1 Lead battery (battery)
4 engine
5 Ignition switch (key)
9 Starter
10 Battery status detection system
12 motor generator (starter for engine start)

Claims (10)

A battery remaining capacity estimating method for estimating a remaining capacity of a battery mounted on a vehicle having an idle stop / start function based on a combination of an internal resistance of the battery calculated at the time of engine start and an integrated current flowing through the battery. ,
Measuring the open circuit voltage of the battery at the time of key-on, calculating the remaining capacity Q _{OCV of the} battery from a predetermined relationship between the remaining capacity of the battery and the open circuit voltage,
Current when the engine is started, calculates the remaining capacity Q _r of the battery from the relationship between the calculated internal resistance internal resistance and the remaining capacity of the battery is predetermined for the battery from the voltage change, the remaining capacity Q _OCV And the remaining capacity Q _{int of the} battery is calculated from the average value of the remaining capacity Q _r and
Engine restart when the current, calculates the remaining capacity Q _C of the battery from the relationship between the calculated and the remaining capacity and the internal resistance of the battery internal resistance of the battery from the voltage variation, the battery before the engine is restarted modifying the corrected remaining capacity Q _res the flow charge and discharge currents were corrected by accumulating the remaining capacity Q _int or remaining capacity Q _C to the remaining capacity Q _C,
A battery remaining capacity estimation method including a step. A battery remaining capacity estimating method for estimating a remaining capacity of a battery mounted on a vehicle having an idle stop / start function based on a combination of an internal resistance of the battery calculated at the time of engine start and an integrated current flowing through the battery. ,
Measuring the open circuit voltage of the battery at the time of key-on, calculating the remaining capacity Q _{OCV of the} battery from a predetermined relationship between the remaining capacity of the battery and the open circuit voltage,
Engine restart when the current, calculates the remaining capacity Q _C of the battery from the relationship between the internal resistance calculated internal resistance and the remaining capacity of the battery is predetermined for the battery from the voltage change, the engine is restarted before the discharge current flowing in the battery to modify the correction remaining capacity Q _res corrected by accumulating the remaining capacity Q _OCV or the remaining capacity Q _C to the remaining capacity Q _C in,
A battery remaining capacity estimation method including a step. 3. The battery according to claim 1, wherein the temperature of the battery is measured, and the measured open circuit voltage of the battery is corrected to an open circuit voltage at a predetermined temperature from a predetermined relationship between the battery temperature and the open circuit voltage. The method for estimating the remaining battery charge according to the above. A battery remaining capacity estimating method for estimating a remaining capacity of a battery mounted on a vehicle having an idle stop / start function based on a combination of an internal resistance of the battery calculated at the time of engine start and an integrated current flowing through the battery. ,
Calculating the internal resistance of the battery from the current and voltage change at the time of starting the engine, and calculating the remaining capacity Q _{int of the} battery from a predetermined relationship between the remaining capacity and the internal resistance of the battery;
Engine restart when the current, calculates the remaining capacity Q _C of the battery from the relationship between the calculated and the remaining capacity and the internal resistance of the battery internal resistance of the battery from the voltage variation, the battery before the engine is restarted modifying the corrected remaining capacity Q _res the flow charge and discharge currents were corrected by accumulating the remaining capacity Q _int or remaining capacity Q _C to the remaining capacity Q _C,
A battery remaining capacity estimation method including a step. The internal resistance is defined as a voltage difference between the battery voltage before the engine is started or before the engine is restarted and the battery voltage after a lapse of a predetermined time after the start of the engine start current or after the start of the engine restart current. The current of the battery before or before the restart of the engine and the current of the battery after a lapse of a predetermined time after the start of energization of the engine start current or after the start of energization of the engine restart current, respectively. The battery remaining capacity estimating method according to any one of claims 1 to 4. 6. The remaining battery capacity estimation method according to claim 5, wherein the predetermined time is within 50 ms from the start of energization of the engine start current or the start of energization of the engine restart current. The battery temperature is measured, and the calculated internal resistance of the battery is corrected to an internal resistance at a predetermined temperature based on a relationship between a predetermined battery temperature and an internal resistance correction value. Item 7. The remaining battery capacity estimation method according to any one of Items 6. 2. The method according to claim 1, further comprising, before the engine start, determining that the engine can be started when the remaining capacity Q _OCV is larger than a minimum remaining capacity Q _min that allows the battery to start the engine. Item 3. The battery remaining capacity estimation method according to Item 2. Before the time of the engine restart, claims, characterized in that the corrected remaining capacity Q _res further comprises a minimum remaining capacity Q _min engine restartable and determining when greater than to allow the engine start of the battery The remaining battery capacity estimation method according to any one of claims 1 to 8. The minimum remaining capacity _Qmin is determined from a minimum voltage value and a required current value determined from characteristics of the engine starter and corresponds to a predetermined maximum internal resistance that allows the battery to start the engine. capacity and internal resistance is set from the relationship between claim 8 or claim, wherein the correction residual capacity Q _res is determined impossible the engine restart when less than the minimum remaining capacity Q _min 10. The method for estimating a remaining battery charge according to claim 9.

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