JP5163739B2 - Battery state detection system and automobile equipped with the same - Google Patents

Description

  The present invention relates to a battery state detection system and an automobile equipped with the same, and more particularly to a battery state detection system for detecting a battery state of a lead battery mounted on a vehicle and an automobile equipped with the battery state detection system.

  In recent years, in order to cope with the reduction of exhaust gas caused by engine cars, restart after engine stop (idle stop / start) has been performed, and a technology for keeping a lead battery in a state where idling can be stopped is desired. That is, in an automobile (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 power from the lead battery. For this reason, the deep discharge of a lead battery increases compared with the past, and there exists a tendency for the residual capacity of a lead battery to become small. Since the output of the lead battery depends on the remaining capacity of the lead battery, if the remaining capacity of the lead battery decreases while the engine is stopped, sufficient output to start the engine may not be obtained, and restart after the engine stops may not be possible. There is.

  Therefore, in order to maintain the restartable state, the remaining capacity of the lead battery and the state of charge (SOC) are calculated (estimated) to monitor the presence or absence of the output required for engine start, and the output required for engine start is In some cases, idling can be stopped, and when there is no output necessary for starting the engine, it is necessary to stop idling and charge the lead battery to send a signal to the vehicle computer.

  Lead batteries are typical batteries that can be used for this type of application. As a technique for estimating the remaining capacity of a lead battery, a technique obtained by measuring the open circuit voltage (OCV) of the lead battery (see, for example, Japanese Patent Laid-Open No. 4-264371), or measuring the internal resistance of the lead battery A technique (for example, refer to Japanese Patent Laid-Open No. 2002-334725) is known. The former technique uses the fact that the relationship between the remaining capacity and the OCV is expressed by a linear expression, and calculates the remaining capacity by substituting the OCV measured when the vehicle is stopped into this expression. In the latter technique, for example, the remaining capacity is calculated by substituting the internal resistance of the lead battery measured at the start of the engine into a map of the internal resistance values of the lead battery corresponding to a plurality of temperatures and the remaining capacity.

  As a technique related to the present invention, a technique for estimating the health state or degree of deterioration (SOH) of a lead battery (see, for example, Japanese Patent Application Laid-Open No. 2006-10601) or an open circuit of a lead battery mounted on a vehicle. Degradation level estimation technology for estimating the degradation level of a lead battery by applying a voltage (OCV) and internal resistance to a map in which the relationship between OCV and internal resistance is defined in advance according to a plurality of degradation levels (for example, Japanese No. 2006-15896) is disclosed.

  When estimating the remaining capacity from the OCV, there are the following problems. As shown in FIG. 2, in a new (100% SOH) lead battery, the remaining capacity and the OCV are almost in a straight line, but as the battery deteriorates, it deviates from this straight line. Therefore, the remaining capacity is calculated from one linear equation. I can't. This problem can be solved by correcting the OCV based on the deterioration degree (SOH) of the lead battery. However, since the deterioration mechanism of the lead battery is complicated, the SOH may not be estimated accurately. That is, in the case of a deteriorated battery, there is a problem that the estimation error of the remaining capacity may increase.

  On the other hand, when estimating the remaining capacity from the internal resistance, there are the following problems. As shown in FIG. 3, this estimation technique has the advantage that the remaining capacity can be calculated without estimating the SOH because it is on the same curve as the new product even if it deteriorates. Since the sensitivity of the internal resistance to the capacity is small, there is a problem that the estimation error of the remaining capacity tends to increase.

  An object of the present invention is to provide a battery state detection system capable of accurately estimating the remaining capacity of a lead battery and an automobile provided with the battery state detection system.

In order to solve the above-mentioned problem, a first aspect of the present invention is a battery state detection system for determining a state of a lead battery mounted on a vehicle, wherein the open circuit voltage (OCV) of the lead battery when the vehicle is stopped is A first remaining capacity estimating unit for calculating the remaining capacity Q _OCV of the lead battery by substituting the relation between the OCV and the remaining capacity into a relational expression or map, and an ignition switch from the lead battery to the cell motor for starting the engine; The internal resistance of the lead battery measured when power is supplied through the battery is substituted into a map or a relational expression of the internal resistance value of the lead battery corresponding to a plurality of temperatures and residual capacities. a second remaining capacity estimating section that calculates a capacity Q _R, before Symbol remaining capacity Q _OCV calculated by the first and second remaining capacity estimating _section, is determined from the error of Q _R and the measured quantity With a coefficient W _OCV, pre-travel remaining capacity estimating unit for estimating the remaining capacity Qf of the lead battery before traveling from W _R, and the travel before the remaining capacity estimating unit coefficients determined from the error of the measured quantity _{W OCV, W W R = δQ} OCV 2 / as ^{_{R (δQ OCV 2 + δQ R}} 2), using the _W OCV = 1-W _R, the remaining capacity Qf of _{Qf = W OCV × Q OCV +} W R · Q R It is estimated by a formula .

  In this aspect, it is preferable that the remaining capacity of the lead battery is estimated by adding a value obtained by multiplying the current integrated value by the charge efficiency of the lead battery to the remaining capacity before traveling when the vehicle is traveling. Moreover, you may make it further provide the determination part which determines the propriety of the engine start of a vehicle from the estimated remaining capacity | capacitance and the resistance value of a vehicle. At this time, the resistance value of the vehicle is obtained by dividing the minimum voltage Vpeak at the engine start by the maximum current Ipeak at the engine start, the vehicle resistance value is OutR, the minimum voltage at the engine start is Vpeak, a lead battery InR can be obtained by OutR = Vpeak × InR / (OCV−Vpeak). Further, when the correlation coefficient of the approximate curve obtained by the least square method using the current and voltage data at the time of starting the engine is smaller than 0.7 to 0.9, it is desirable that the remaining capacity before running is 0 Ah. For example, when the correlation coefficient of the approximate curve obtained by the least square method using the current and voltage data at engine start is less than 0.8, the remaining capacity before running may be set to 0 Ah. In addition, it has a power measurement unit that measures the amount of charge / discharge electricity of the lead battery, and the power measurement unit is determined by substituting the battery temperature and voltage data into a charging efficiency map or relational expression corresponding to a plurality of temperatures and voltages. The charging efficiency may be used. Further, it is desirable that the OCV is corrected by the dark current flowing from the lead battery to the vehicle load when the vehicle is stopped, the deterioration degree (SOH) of the lead battery, and the battery temperature.

  Moreover, in order to solve the said subject, the 2nd aspect of this invention is a motor vehicle provided with the battery state detection system of the 1st aspect.

According to the present invention, a remaining capacity estimating unit before traveling, direct measurement of coefficient _W OCV determined from the error, _W with _R, remaining capacity Qf the _{Qf = W OCV × Q OCV +} W of the lead battery before traveling since estimated by the formula _R · Q _R, it is possible to accurately estimate the remaining capacity of a lead battery, it is possible to obtain an effect that.

  Embodiments of an automobile according to the present invention will be described below with reference to the drawings.

(Constitution)
As shown in FIG. 1, the automobile 100 of this embodiment is a gasoline engine car. The automobile 100 is, for example, a liquid lead battery 1 and a battery of the lead battery 1 disposed on the lead battery 1 in an engine room. A battery state detection system 12 for determining the state. In the present embodiment, the lead battery 1 and the battery state detection system 12 are integrated.

  As shown in FIG. 4, the battery state detection system 12 includes a temperature sensor 2 such as a thermistor that measures the temperature of the lead battery 1, a differential amplifier circuit, and the like, and a voltage measurement unit that is connected to an external terminal of the lead battery 1. 3. A current sensor 4 such as a Hall element and a microcomputer (hereinafter referred to as a microcomputer) 10 for detecting the battery state of the lead battery 1 are provided.

  The lead battery 1 has a substantially rectangular battery case serving as a battery container, and a total of six electrode plate groups are accommodated in the battery case. As the material of the battery case, for example, a polymer resin such as polyethylene (PE) can be used. Each electrode plate group is formed by laminating a plurality of negative plates and positive plates with a separator interposed therebetween, and the cell voltage is 2.0V. For this reason, the nominal voltage of the lead battery 1 is set to 12V. The upper part of the battery case is bonded or welded to an upper lid made of a polymer resin such as PE that seals the upper opening of the battery case. A rod-like positive electrode terminal and a negative electrode terminal for supplying electric power to the outside using the lead battery 1 as a power source are erected on the upper lid. In addition, the temperature sensor mentioned above is being fixed to the side part or bottom face part of a battery case.

  A positive terminal of the lead battery 1 is connected to a central terminal of an ignition switch (hereinafter referred to as “IGN”) 5 through a current sensor 4. The IGN5 has an OFF terminal, an ON / ACC terminal, and a START terminal in addition to the central terminal. The central terminal and any of these OFF, ON / ACC, and START terminals can be switched in a rotary manner. is there.

  The START terminal is connected to an engine starting cell motor (starter) 9. The cell motor 9 can transmit a rotational driving force to the rotating shaft of the engine 8 via a clutch mechanism (not shown).

  The ON / ACC terminal is a generator (alternator) 7 that generates electric power by rotation of the engine 8 via an auxiliary device 6 such as an air conditioner, a radio, a lamp, and a regulator including a rectifying element that allows current flow in one direction. It is connected to one end. That is, the anode side of the regulator is connected to one end of the generator 7, and the cathode side is connected to the ON / ACC terminal. The rotating shaft of the engine 8 can transmit power to the generator 7 via a clutch mechanism (not shown). For this reason, when the engine 8 is in a rotating state, the generator 7 is operated via a clutch mechanism (not shown), and the electric power from the generator 7 is supplied (charged) to the auxiliary machine 6 and the lead battery 1. Note that the OFF terminal is not connected to any of them.

  The output side of the voltage measuring unit 3 is connected to an A / D converter built in the microcomputer 10. The output sides of the temperature sensor 2 and the current sensor 4 are connected to an A / D converter built in the microcomputer 10 respectively. For this reason, the microcomputer 10 can take in the voltage and temperature of the lead battery 1 and the current flowing through the lead battery 1 as digital values every predetermined time. The microcomputer 10 can communicate with the host vehicle control system 11 via the I / O.

  The microcomputer 10 functions as a CPU that functions as a central processing unit, a basic control program for the battery state detection system 12, a ROM that stores program data such as maps and mathematical formulas described later, and a work area for the CPU and temporarily stores the data. It includes a RAM for storage, a nonvolatile EEPROM, and the like. The other end of the generator 7, the cell motor 9 and the auxiliary machine 6, the negative terminal of the lead battery 1, and the microcomputer 10 are each connected to the ground (the same potential as the chassis of the automobile). Note that the microcomputer 10 of the present embodiment samples the voltage, current, and temperature at predetermined time intervals (for example, the voltage and current are each 2 milliseconds and the temperature is 1 second), and the sampling result is stored in the RAM. . The current is divided into a discharge current and a charge current, and an integrated value of each is calculated.

(Operation)
Next, the operation of the battery state detection system 12 will be described in the order of detection of the engine state, estimation of the remaining capacity of the lead battery 1, and determination of whether or not the engine can be started.
<1. Engine status detection>

  The CPU of the microcomputer 10 (hereinafter simply referred to as “CPU”) measures the voltage of IGN5 (the configuration is omitted in FIG. 4). For example, when the voltage of IGN5 is increased from about 0V to 12V or more, IGN5 is turned on. It is located at the / ACC terminal position, and it is determined that IGN5 is located at the OFF terminal position when the voltage of IGN5 changes from a voltage of 12 V or higher to a voltage of about 0 V, and the vehicle ignition switch is turned on or off (depending on the key) Engine start, engine stop). If the IGN 5 is of a type that outputs a signal regarding the terminal position, the engine state may be detected by the signal or a signal from the vehicle control system 11.

  In general, in an automobile having an internal combustion engine such as a gasoline engine car or a diesel engine car, electric power is supplied from a lead battery and a cell motor is rotated to start the engine. At this time, a large current flows, and accordingly, the voltage between the terminals of the lead battery 1 greatly decreases. When the voltage drop and the time change of the current at this time are measured, a sharp peak-shaped large current flows immediately after the current starts to flow through the cell motor, and at the same time, the voltage between the terminals of the lead battery 1 shows a sharp valley-shaped voltage drop. (See also FIG. 6). As will be described later, Ohm's law is established between the minimum voltage value Vpeak of the lead battery at the time of starting the engine, the maximum current value Ipeak flowing in the lead battery, and the resistance value of the automobile (vehicle). In other words, the Ohm's law is established only for a moment when the minimum voltage value Vpeak and the maximum current value Ipeak are taken, and the Ohm's law is not established otherwise.

  The CPU takes in the voltage of the lead battery 1 measured through the voltage measuring unit 3 as an OCV at a predetermined time after the polarization reaction of the lead battery 1 is canceled after the engine is stopped. The CPU enters a power saving mode in which only the timer is operated and no other control operation is performed. When the timer reaches a predetermined time, the OCV is taken in and the power saving mode is entered again.

<2. Calculation of remaining capacity of lead battery 1>
In general, the remaining capacity Q (Ah) of the lead battery can be obtained by the following equation (1). In equation (1), Qf represents the pre-travel capacity, Qout represents the discharge current integrated value, Qin represents the charge current integrated value, and c represents the charging efficiency.

  The pre-travel capacity Qf can be obtained from the OCV measured when the vehicle is stopped and the internal resistance when the engine is started. Generally, in a lead battery, it takes 2 to 10 hours or more until polarization due to charge / discharge is eliminated. For this reason, in this embodiment, OCV in the state which passed 6 hours or more after the vehicle stop was employ | adopted. When 6 hours or more did not elapse, the estimated remaining capacity at the end of the previous run was taken as the pre-travel capacity. That is, the CPU stores the estimated remaining capacity at the end of the previous run in the EEPROM, determines whether or not 6 hours or more have elapsed since the vehicle stopped, and from the EEPROM at the end of the previous run when a negative determination is made. The estimated remaining capacity is read and used. On the other hand, the pre-travel capacity Qf when 6 hours or more have elapsed can be obtained as follows.

2-1. Calculation of pre-travel capacity Qf 2-1-1. Calculation of remaining capacity Q OCV from _OCV First, the dark current drop is corrected by the following method for the OCV measured when the vehicle is stopped. FIG. 5 shows the relationship between the OCV when a dark current of 25 mA is discharged at 0 ° C. and the OCV at 25 ° C. (true) in a no-load state. Since the internal resistance of the deteriorated product is large, the voltage drop is larger than that of a new product (SOH 100%). For this reason, it shifts to the left as shown in FIG. The approximate line of SOH 100% was f3 (x), and the approximate line of SOH 40% was f4 (x). Similarly, as shown in Table 1 below, an approximate line of SOH 100% and an approximate line of SOH 40% can be obtained for −20, 0, 25, 60 ° C. and dark current 25, 32, 75 mA.

  The voltage measurement value OCVb is substituted into this correction formula, and an OCV of 25 ° C. (OCVb — 25) is calculated by proportional calculation. As an example, a case where dark current Ix> 32 mA and battery temperature T <0 ° C. will be described.

1) 25 ° COCV (Data 1) at 32 mA, −20 ° C. and SOH 40% can be expressed by Data 1 = f9 (OCVb). Further, 25 ° COCV (Data 2) at 32 mA, −20 ° C. and SOH 100% can be expressed by Data 2 = f10 (OCVb). Therefore, 25 ° COCV (Data 3) at 32 mA, −20 ° C., SOH (SOH)% is Data 3 = Data 2+ (Data 1−Data 2) × (100−SOH) / (100−40) 2).

2) On the other hand, 25 ° COCV (Data 4) at 32 mA, 0 ° C., and 40% SOH can be expressed by Data 4 = f11 (OCVb). Further, 25 ° COCV (Data 5) at 32 mA, 0 ° C., and SOH 100% can be expressed by Data 5 = f12 (OCVb). Therefore, 25 ° COCV (Data 6) at 32 mA, 0 ° C. and SOH (SOH)% is Data 6 = Data 5+ (Data 4 -Data 5) × (100−SOH) / (100−40) (3) ).

3) From 1) and 2) above, 25 ° COCV (Data 7) at 32 mA, T ° C, SOH (SOH)% is Data 7 = Data 6+ (Data 3 -Data 6) × (0−T) / (0−T) (−20))... (4) Similarly, 25 ° COCV (Data 8) at 75 mA, T ° C., and SOH (SOH)% can be obtained.

4) From 3) above, 25 ° COCV (OCVb — 25) can be obtained as OCVb — 25 = Data8 + (Data7−Data8) × (75−Ix) / (75−32) (5).

  This OCVb_25 is further subjected to SOH correction by the following method. As shown in FIG. 2, the OCV of the deteriorated product translates upward from the straight line of the new product (SOH 100%). Assuming that bV is translated upward with respect to a new product at SOHc%, the OCV correction value ΔOCV at SOHx% is expressed by ΔOCV = d × (100−x) / (100−c) (6) The

Assuming that the linear expression of the new straight line shown in FIG. 2 is Q _OCV = (OCVb — 25−b) / a (7) (a and b are constants), the linear expression of the deteriorated product is Q _OCV = (OCVb — 25−ΔOCV−b) / a (Expression (8)) When the remaining capacity Q _OCV is larger than the full charge capacity defined by SOH (= (full charge capacity at new article) × SOH / 100), Q _OCV = (full charge capacity defined by SOH). .

Here, when the measurement error of the OCV and DerutaOCV, error .delta.Q _OCV of the remaining capacity _{Q OCV is, δQ OCV = {(OCVb_25-} ΔOCV + δOCV-b) / a - ((OCVb_25-ΔOCV-δOCV-b) / a)} / 2 ... It can be expressed by equation (9).

In the present embodiment, a relational expression (equation (8)) between the remaining capacities Q _OCV and OCV, an error calculation expression (equation (9)), and the like are stored as program data in the ROM, and the CPU is expanded in the RAM. The remaining capacity Q _{OCV and the} like are calculated using these program data. In addition, SOH can be calculated | required with the technique described in patent document 3, for example.

2-1-2. Internal resistance calculation lead battery 1 remaining capacity Q _R from the internal resistance, as shown in FIG. 6, for example, during engine start (when supplying power to the starter motor 9 via a lead battery 1 IGN5) - It can be determined as the slope of the approximate line calculated from the voltage-current data in the range of 100 to -200 A by the least square method. As shown in FIG. 7, a map of internal resistance and battery temperature is created in advance (in this embodiment, it is expanded from ROM to RAM). The map to substitute the internal resistance and the battery temperature at the time of starting the engine to calculate the remaining capacity Q _R.

Specifically, for example, determine the Q-R relationship in t ° C by proportional calculation from the measured battery temperature t ° C, it assigns the internal resistance value determining the remaining capacity Q _R. Here, if the full charge capacity of the remaining capacity _{Q R} is defined by SOH (= (the full charge capacity at the time of a new) × SOH / 100) greater than _(full-charge capacity, which is defined by SOH) Q R = a To do.

When the fa () and the internal resistance R, the function for obtaining the remaining capacity from the battery temperature t, the error .delta.Q _R of the remaining capacity _{Q R is, δQ R = {fa (R} + δR, t) -fa (R-δR, t)} / 2 ... It can be expressed by equation (10). In Equation (10), δR is an internal resistance measurement error. The measurement error of the battery temperature was omitted because it was smaller than the internal resistance.

In the present embodiment, the above-described map, relational expression, error calculation expression (formula (10)), and the like are stored as program data in the ROM, and the CPU uses these program data expanded in the RAM to remain. to calculate the capacity _{Q R} and the like.

2-1-3. Calculation of pre-travel capacity Qf (error reduction process)
The CPU, in order to improve the calculation accuracy, the weighted average based on minimum error principle, the pre-travel capacity Qf, described above, the following equation from both the remaining capacity Q _R from the remaining capacity Q _OCV and internal resistance from OCV Qf = W _OCV × Q _OCV + W _R · Q _R (Equation 11) Here, the coefficient _{W R ^{is, W R = δQ OCV 2 /}} (δQ OCV 2 + δQ R 2) ··· Equation (12), the coefficient _{W OCV is, W OCV = 1-W R} ··· formula (13) It is.

2-1-4. Overdischarge determination The correlation coefficient of the approximate line (see 2-1-2) shown in FIG. 6 and the remaining capacity of the lead battery 1 are in the relationship shown in FIG. As shown in FIG. 8, when the correlation coefficient is small, the pre-travel capacity Qf is approximately 0 Ah. For this reason, in this embodiment, the CPU determines whether or not the correlation coefficient is less than 0.8. When the determination is affirmative (correlation coefficient <0.8), the pre-travel capacity Qf = 0 Ah, and the negative determination For (correlation coefficient ≧ 0.8), a step (algorithm) was added in which pre-travel capacity Qf = calculated pre-travel capacity Qf.

2-2. Calculation of Charging Efficiency c As shown in FIG. 9, a map of battery voltage and battery temperature is created in advance (in this embodiment, it is expanded from ROM to RAM). The measured battery voltage V and battery temperature t are substituted into this map to estimate the charging efficiency c. Specifically, for example, a Vc relational expression at t ° C is obtained from the measured battery temperature t ° C by proportional calculation, and the battery voltage value is substituted into the equation to obtain the charging efficiency c.

  The CPU estimates the pre-traveling capacity Qf when 6 hours or more have elapsed by substituting the values obtained as described above into Equation (1). Further, as apparent from the equation (1), during the vehicle traveling, the remaining capacity of the lead battery 1 is obtained by adding a value obtained by multiplying the current integrated value by the charging efficiency c of the lead battery 1 to the pre-travel capacity Qf. presume. In the present embodiment, in order to clarify the explanation, the formula is clearly shown for each step. However, a formula summarizing these may be used.

<3. Determining whether the engine can be started>
FIG. 10 shows an equivalent circuit when starting the engine. From FIG. 10, the following expressions (14) and (15) hold. In the equations (14) and (15), Vpeak is the minimum voltage value of the lead battery 1 at the time of starting the engine, Ipeak is the maximum current value flowing through the lead battery 1 at the time of starting the engine, OutR is the resistance value of the automobile, and InR is The internal resistance value of the lead battery 1 is represented.

  From expressions (14) and (15), Vpeak = (OCV × OutR) / (InR + OutR) (17) is established.

The CPU substitutes the current remaining capacity estimation value Q, the OCV (OCV _Q ) obtained from the temperature, and the internal resistance (InR _Q ) into the equation (17), thereby estimating the minimum voltage at the time of engine (re) starting. Vexp is calculated.

That is, Vexp = (OCV _Q × OutR) / (InR _Q + OutR) (Equation 18) is used to calculate an estimated value Vexp of the minimum voltage at the time of engine start. _{However, OCV Q = (Q × a} ) + b ··· formula (18), a OutR = Vpeak / Ipeak ··· formula (19), InR _Q creates current remaining capacity estimation value Q, the temperature in advance This is the internal resistance obtained by assigning to a certain map. Since OutR can be regarded as substantially constant during the use period of the lead battery 1, in this embodiment, the minimum voltage value Vpeak of the lead battery 1 when the engine is started several times after the battery is mounted (or replaced) is the maximum current value Ipeak. The value divided by (average value) was obtained, the value was stored in the EEPROM, and the stored value was read and used as the automobile resistance value OutR. Also, since OutR may differ slightly depending on the temperature, temperature correction may be performed.

  When the measurement range of the current sensor 2 is narrow and Ipeak cannot be measured, it may be calculated as OutR = Vpeak × InR / (OCV−Vpeak) (Equation 20). By using such a calculation formula, the cost of the current sensor 2 can be reduced. In Expression (20), InR is an internal resistance calculated by approximating the IV data at the time of starting the engine to the least square.

  The CPU determines whether or not the estimated value Vexp of the minimum voltage at the time of starting the engine is Vexp ≦ Vmin (formula (21)) with respect to the minimum voltage value Vmin for starting the engine. The vehicle control system 11 is notified that the restart is impossible, and the vehicle control system 11 is notified that the restart is impossible, and the vehicle control system 11 is notified that the restart (ISS) is possible even if the engine is stopped. To do. The vehicle control system 11 that has received the negative determination notification charges the lead battery 1 by continuously operating the generator 7 without stopping the engine. The minimum voltage value Vmin for starting the engine is about 6.8 to 7.8 V, although it varies depending on the vehicle, and is set to 7.2 V in this embodiment.

(Effects etc.)
Next, functions and effects of the vehicle according to the present embodiment will be described focusing on functions and effects of the battery state detection system 12.

Battery state detection system 12, the remaining capacity _Q OCV, _{Q R} and measuring the amount of coefficient _W OCV determined from the error, calculating the _{W R,} From these estimates the traveling before capacity Qf the lead battery 1 (formula (11)). For this reason, the principle error in estimating the remaining capacity from the OCV as in the prior art and the principle error in estimating the remaining capacity from the internal resistance can be reduced, so the remaining of the lead battery 1 before traveling can be reduced. The capacity can be estimated accurately. Further, when the vehicle is traveling, the remaining capacity Q of the lead battery 1 is estimated by adding a value obtained by multiplying the current integrated value by the charging efficiency c of the lead battery 1 to the pre-travel capacity Qf. Therefore, the remaining capacity of the lead battery 1 during traveling of the vehicle can be accurately grasped because the pre-traveling capacity Qf is accurately estimated and the actual charge / discharge current during traveling is integrated.

  Further, the battery state detection system 12 sets the pre-travel capacity Qf to 0 Ah when the correlation coefficient of the approximate curve obtained by the least square method using the current and voltage data when starting the engine is less than 0.8. As a result, the pre-travel capacity Qf reflecting the actual remaining capacity of the lead battery 1 can be obtained.

  Further, the battery state detection system 12 determines whether or not the engine of the automobile can be started based on the accurately estimated remaining capacity Q of the lead battery 1 while the vehicle is running and the actual resistance value OutR of the automobile (Formula (18)). (21)). For this reason, it is possible to improve the accuracy of whether or not the engine can be started.

  In addition, since the automobile of the present embodiment includes the battery state detection system 12 that can accurately estimate the remaining capacity of the lead battery 1, engine restart can be ensured at the time of idling stop / start.

  In the present embodiment, it is determined whether or not the correlation coefficient is less than 0.8. When an affirmative determination is made (is a pre-travel capacity Qf = 0 Ah, a negative determination is a pre-travel capacity Qf = a calculated pre-travel capacity Although an example of Qf has been shown, the present invention is not limited to this, and for example, the range of the correlation coefficient can be set within a range of 0.7 to 0.9.

  Moreover, in this embodiment, although the 14V type liquid lead battery was illustrated as the lead battery 1, this invention is not limited to this. For example, the present invention can be applied to a 42V liquid lead battery, a lead battery in which an electrolytic solution is contained in a retainer, a kind of bipolar battery of a lead battery, and the like. Furthermore, in the present embodiment, an automobile having an idle stop / start function is illustrated, but it goes without saying that the present invention can be applied to an automobile having no such function.

  Furthermore, in the present embodiment, the Hall type current sensor is exemplified, but the present invention is not limited to this, and a shunt type current sensor may be used. In this embodiment, an example in which the detection of the engine state is detected by grasping the voltage fluctuation has been shown. However, it may be grasped by the current fluctuation or by both the voltage fluctuation and the current fluctuation. Good.

  In the present embodiment, one of the map or the relational expression is exemplified. However, the CPU can perform the calculation by replacing the map with the relational expression or the relational expression with the map, and the software by the microcomputer 10 is hardware. We can't wait for the possibility of substituting.

  Since the present invention provides a battery state detection system capable of accurately estimating the remaining capacity of a lead battery and a vehicle equipped with the battery state detection system, it contributes to the manufacture and sale of the battery state detection system and the vehicle. Therefore, it has industrial applicability.

It is a schematic diagram of the motor vehicle of embodiment which can apply this invention. It is explanatory drawing which shows the relationship between the remaining capacity of 14V system lead battery, and OCV. It is explanatory drawing which shows the relationship between the residual capacity of a lead battery and internal resistance in the battery temperature of 25 degreeC. It is a block circuit diagram of a car of an embodiment. It is a characteristic diagram which shows the relationship between OCV when 25 mA of dark currents are discharged at 0 degreeC, and 25 degreeCOCV. It is explanatory drawing which shows the calculation method of internal resistance typically. It is a map of battery temperature, internal resistance, and remaining capacity. It is explanatory drawing which shows the relationship between remaining capacity and a correlation coefficient. It is a map of battery temperature, voltage, and charging efficiency. It is a circuit diagram which shows the equivalent circuit of the motor vehicle at the time of engine starting.

Explanation of symbols

1 Lead battery 10 Microcomputer (a part of the first remaining capacity estimating part, a part of the second remaining capacity estimating part, a remaining capacity estimating part before traveling, a judging part, a power measuring part)
12 battery state detection system 100 automobile

Claims (15)

In a battery state detection system for determining the state of a lead battery mounted on a vehicle,
The first remaining capacity for calculating the remaining capacity Q _OCV of the lead battery by substituting the open circuit voltage (OCV) of the lead battery when the vehicle is stopped into a relational expression or map that defines the relationship between the _OCV and the remaining capacity. An estimation unit;
The internal resistance of the lead battery measured when power is supplied from the lead battery to an engine starting cell motor via an ignition switch, a map or relationship of the internal resistance values of the lead battery corresponding to a plurality of temperatures and remaining capacities. a second remaining capacity estimating section that calculates a remaining capacity Q _R of the lead battery by substituting in the equation,
Before Symbol remaining capacity Q _OCV calculated by the first and second remaining capacity estimating _section, the coefficient W _OCV determined from the error of Q _R and the measured _quantity, the remaining capacity Qf of the lead battery before traveling from W _R A pre-travel remaining capacity estimation unit to estimate,
With
The pre-travel remaining capacity estimating section, the coefficient _W OCV is determined from the error of the measured ^{_{quantity, W R = δQ OCV 2 /}} (δQ OCV 2 + δQ R 2) as _{W R,} using the _W OCV = 1-W _R The remaining capacity Qf is estimated by an equation of Qf = W _OCV × Q _OCV + W _R · Q _R.   2. The remaining capacity of the lead battery is estimated by adding a value obtained by multiplying a current integrated value by the charging efficiency of the lead battery to the remaining capacity before the traveling when the vehicle travels. Battery status detection system.   The battery state detection system according to claim 1, further comprising a determination unit that determines whether or not the vehicle engine can be started based on the estimated remaining capacity and the resistance value of the vehicle.   4. The pond state detection system according to claim 3, wherein the resistance value of the vehicle is obtained by dividing a minimum voltage Vpeak at the start of the engine by a maximum current Ipeak at the start of the engine.   The resistance value of the vehicle is obtained by OutR = Vpeak × InR / (OCV−Vpeak), where OutR is the resistance value of the vehicle, Vpeak is the minimum voltage at engine start, and InR is the internal resistance of the lead battery. The pond state detection system according to claim 3.   The battery state detection system according to claim 2, further comprising a determination unit that determines whether the engine of the vehicle can be started based on the estimated remaining capacity and the resistance value of the vehicle.   7. The pond state detection system according to claim 6, wherein the resistance value of the vehicle is obtained by dividing a minimum voltage Vpeak at the start of the engine by a maximum current Ipeak at the start of the engine.   The resistance value of the vehicle is obtained by OutR = Vpeak × InR / (OCV−Vpeak), where OutR is the resistance value of the vehicle, Vpeak is the minimum voltage at engine start, and InR is the internal resistance of the lead battery. The pond state detection system according to claim 6.   When the correlation coefficient of the approximate curve obtained by the least square method using current and voltage data at the time of engine start is smaller than 0.7 to 0.9, the remaining capacity before running is set to 0 Ah. The battery state detection system according to claim 1.   10. The remaining capacity before running is set to 0 Ah when a correlation coefficient of an approximate curve obtained by a least square method using current and voltage data at engine start is less than 0.8. The battery state detection system as described.   When the correlation coefficient of the approximate curve obtained by the least square method using current and voltage data at the time of engine start is smaller than 0.7 to 0.9, the remaining capacity before running is set to 0 Ah. The battery state detection system according to claim 2.   12. The remaining capacity before running is set to 0 Ah when the correlation coefficient of the approximate curve obtained by the least square method using current and voltage data at engine start is less than 0.8. The battery state detection system as described.   The power measurement unit includes a power measurement unit that measures the amount of charge / discharge electricity of the lead battery, and the power measurement unit is determined by substituting battery temperature and voltage data into a map or relational expression of charge efficiency corresponding to a plurality of temperatures and voltages. The battery state detection system according to claim 2, wherein charging efficiency is used.   2. The battery state detection system according to claim 1, wherein the OCV is corrected by a dark current flowing from the lead battery to a vehicle load when the vehicle is stopped, a deterioration degree (SOH) of the lead battery, and a battery temperature.   An automobile provided with the battery state detection system according to any one of claims 1 to 14.

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