JP4702115B2 - Battery status judgment device - Google Patents

Description

  The present invention relates to a battery state determination device, and more particularly to a battery state determination device that determines a battery state of a battery mounted on a vehicle.

  In recent years, internal resistance, discharge voltage, open circuit voltage, remaining capacity, state of charge, etc. have been used as parameters representing battery state or measurement parameters for calculating battery state. As the load on the batteries used for automobiles and portable devices increases, the importance of such battery state monitoring and battery state control is increasing. Yes. In order to cope with idle stop / start (ISS), regenerative charging, and the like performed for reducing exhaust gas, a vehicle battery is required to have a technology for keeping the battery in a battery state suitable for these applications. Lead batteries are one of the typical batteries that can be applied to these applications.

  In order to meet such demands, there has been proposed a battery remaining capacity detection device for a hybrid vehicle that calculates a battery state by comparing a voltage and DC internal resistance at the time of starting an engine with a data map measured in advance (for example, for vehicles) (for example, , See Patent Document 1).

  As a battery test method using a vehicle, a method for evaluating a voltage in a state where a starter motor is rotated is known. This method has been used for a long time as a battery check method for investigating whether a starter or a battery is the cause of a vehicle whose engine cannot be started. In this method, measurement with a simple voltmeter that does not use an oscilloscope and has a slow time response is common. For example, if the voltage is relatively stable after an inrush current, the voltage is determined to be normal if the voltage is about 9 V or higher. To do. If measures are taken not to supply fuel to the engine so that the engine does not actually start even if the starter motor rotates, a time-stable voltage can be obtained even in a normal vehicle, and battery check Can do.

JP-A-7-63830

  However, conventionally, the method of calculating the battery state from the voltage at the time of starting the engine is considered as a simple method, and no detailed examination has been made on the method of temperature correction. The voltage at the start of the engine varies greatly depending on the battery type, vehicle type, vehicle temperature, and measurement time. In order to estimate the battery state of the battery mounted on the vehicle, it is necessary to remove the influence of the type of vehicle and the temperature of the vehicle. As shown in FIG. 6, when the engine is started, the voltage of the battery greatly decreases first and then increases to relatively stabilize the voltage. The voltage at this time (engine start voltage) is affected by the temperature of the vehicle, but since the handling method of the voltage at the time of engine start considering the effect of the temperature of the vehicle has not been established, the battery of the battery mounted on the vehicle It was difficult to calculate the state with high accuracy.

  An object of the present invention is to provide a battery state determination device that can accurately determine a battery state of a battery from an engine starting voltage in consideration of the influence of the temperature of the vehicle.

In order to solve the above-mentioned problem, according to a first aspect of the present invention, there is provided a battery state determination device for determining a battery state of a battery mounted on a vehicle, and an open circuit voltage measurement unit that measures an open circuit voltage OCV of the battery. Engine starting voltage measuring means for measuring an engine starting voltage Vst representing a voltage at the time of starting the engine of the battery, vehicle temperature measuring means for measuring the temperature of the vehicle, and an open circuit voltage measured by the open circuit voltage measuring means. Engine starting voltage correcting means for calculating an engine starting voltage Vst1 obtained by correcting the engine starting voltage Vst measured by the engine starting voltage measuring means based on a circuit voltage OCV and a vehicle temperature measured by the vehicle temperature measuring means; From the open circuit voltage OCV measured by the open circuit voltage measuring means, the rate of increase of the internal resistance of the battery is battery replacement. Determination voltage calculation means for calculating a battery determination voltage Vst_th that represents a voltage at the time of engine start of the battery when reaching a predetermined value, and the engine start voltage Vst1 calculated by the engine start voltage correction means is the determination voltage Battery state determination means for determining whether or not the battery determination voltage Vst_th measured by the calculation means is equal to or greater than the battery determination voltage Vst_th , wherein the open circuit voltage measurement means obtains a stable open circuit voltage OCV when dark current is flowing from the battery. The engine start voltage correction means and the determination voltage calculation means measure the corrected open circuit voltage obtained by adding a correction amount that is a function of temperature to the open circuit voltage OCV measured by the open circuit voltage measurement means. The engine start voltage Vst1 and the battery determination voltage Vst_th are calculated using a circuit voltage OCV1. That.

In the first aspect, the open circuit voltage OCV of the battery is measured by the open circuit voltage measuring means, the engine starting voltage Vst representing the voltage at the time of starting the engine of the battery is measured by the engine starting voltage measuring means, and the vehicle temperature measuring means is measured. The temperature of a vehicle such as a starter is measured. Based on the open circuit voltage OCV measured by the open circuit voltage measuring means and the vehicle temperature measured by the vehicle temperature measuring means by the engine starting voltage correcting means, the engine starting voltage Vst measured by the engine starting voltage measuring means is obtained. When the corrected engine starting voltage Vst1 is calculated and the increase rate of the internal resistance of the battery reaches a predetermined value for battery replacement from the open circuit voltage OCV measured by the open circuit voltage measuring means by the determination voltage calculating means A battery determination voltage Vst_th representing a voltage at the time of engine start of the battery is calculated. The battery state determination unit determines whether the engine start voltage Vst1 calculated by the engine start voltage measurement unit is equal to or higher than the battery determination voltage Vst_th calculated by the determination voltage calculation unit, thereby determining the battery state of the battery. Is done. At this time, the open circuit voltage measuring means measures a stable open circuit voltage OCV when dark current is flowing from the battery, and the engine starting voltage correcting means and the determination voltage calculating means are measured by the open circuit voltage measuring means. Since the engine start voltage Vst1 and the battery determination voltage Vst_th are calculated using the corrected open circuit voltage OCV1 obtained by adding a correction amount that is a function of temperature to the open circuit voltage OCV, the open circuit voltage OCV is also a temperature. Since the correction is made, the battery state of the battery can be determined with higher accuracy. According to this aspect, the engine start voltage Vst1 obtained by correcting the engine start voltage Vst in consideration of the influence of the vehicle temperature is calculated by the engine start voltage correction means, and the engine start voltage Vst1 is calculated by the battery state determination means. Since it is determined whether or not Vst_th or more, the influence of the temperature of the vehicle is eliminated in determining the battery state, so that the battery state of the battery can be accurately determined , and the open circuit voltage measuring means can detect the dark current from the battery. A stable open circuit voltage OCV when the engine is flowing is measured, and the engine starting voltage correcting means and the determination voltage calculating means add a correction amount that is a function of temperature to the open circuit voltage OCV measured by the open circuit voltage measuring means. The engine start voltage Vst1 and the battery determination voltage Vs using the corrected open circuit voltage OCV1 obtained by adding For calculating the - th, since the open circuit voltage OCV is also the temperature correction can be determined more accurate battery state of the battery.

In order to solve the above problems, a second aspect of the present invention provides an open circuit voltage for measuring an open circuit voltage OCV of a battery in a battery state determination device for determining a battery state of a battery mounted on a vehicle. Measured by a measuring means, an engine starting voltage measuring means for measuring an engine starting voltage Vst representing a voltage at the time of starting the engine of the battery, a battery temperature measuring means for measuring the temperature of the battery, and the open circuit voltage measuring means. Engine starting voltage correcting means for calculating an engine starting voltage Vst1 obtained by correcting the engine starting voltage Vst measured by the engine starting voltage measuring means based on the open circuit voltage OCV and the vehicle temperature; and the open circuit voltage measuring means From the open circuit voltage OCV measured in step 1, the increase rate of the internal resistance of the battery reaches a predetermined value for battery replacement. A determination voltage calculating means for calculating a battery determination voltage Vst_th representing a voltage at the time of engine start of the battery, and the engine starting voltage Vst1 calculated by the engine starting voltage correcting means is measured by the determination voltage calculating means. Battery state determination means for determining whether or not the battery determination voltage is greater than or equal to the battery determination voltage Vst_th, wherein the open circuit voltage measurement means measures a stable open circuit voltage OCV when dark current is flowing from the battery, and the engine The starting voltage correcting means and the determination voltage calculating means use the corrected open circuit voltage OCV1 obtained by adding a correction amount that is a function of temperature to the open circuit voltage OCV measured by the open circuit voltage measuring means. the calculated engine starting voltage Vst1 and the battery determination voltage Vst_th Te, the engine starting voltage correcting means The measured temperature of the battery by the battery temperature measuring means after a lapse of a predetermined time from the engine stop is regarded as the temperature of the vehicle, characterized in that computing the engine starting voltage Vst1.

  The second aspect includes battery temperature measurement means for measuring the battery temperature instead of the vehicle temperature measurement means of the first aspect, and the engine start voltage correction means measures the battery temperature after a predetermined time or more has elapsed since the engine stopped. The engine starting voltage Vst1 is calculated by regarding the battery temperature measured by the means as the vehicle temperature. In such an aspect, in addition to being able to obtain the same operations and effects as the first aspect, it is not necessary to directly measure the temperature of a vehicle such as a starter, as in the first aspect. It is possible to save a lot of time and effort when mounting the determination device, and to shorten the length of the lead wire from the vehicle temperature measurement position to the battery state determination device, thereby reducing the influence of noise and the like. it can.

  In the first and second aspects, the engine start voltage correction means corrects the vehicle temperature to T, the temperature correction reference temperature to T0, and the vehicle electric resistance at the time of engine start to a value at the reference temperature T0. The engine starting voltage Vst1 may be calculated by the following equation (1), where α is the temperature correction coefficient and A is a constant that takes a range of 0.9 to 1.1.

  At this time, the temperature correction coefficient α is preferably a temperature correction coefficient of the electrical resistance of the copper wire.

  Further, in the first and second aspects, the determination voltage calculation means sets the internal resistance at the open circuit voltage OCV = OCV0 (12.4V ≦ OCV0 ≦ 13.0V) of a new battery to r0, for battery replacement When the internal resistance threshold value of the battery is r_th, the electric resistance of the vehicle is R, and the constant taking a range of 0.9 to 1.1 is B, the battery replacement determination voltage Vst_th is calculated by the following equation (2). You may make it do.

  In this case, if (r_th / r0) in equation (2) is calculated as a constant within the range of 1.2 to 1.6, it is not necessary to measure the internal resistance threshold value r_th or the internal resistance r0, and the battery Since it is not necessary to provide a current sensor in the state determination device, the cost of the battery state determination device can be reduced. At this time, when the engine start voltage Vst when the open circuit voltage OCV of the new battery takes OCV0 is Vst0, the vehicle can be obtained by calculating (r0 / R) of the equation (2) by the following equation (3). Even if the electrical resistance R is unknown, the battery determination voltage Vst_th can be calculated. Furthermore, it is preferable to calculate the engine start voltage Vst0 of the formula (3) by the following formula (4).

  The first aspect further includes battery temperature measuring means for measuring the temperature of the battery, and the engine starting voltage correcting means has a correction amount corresponding to the battery temperature measured by the battery temperature measuring means in a one-to-one relationship. Is added to the engine starting voltage Vst1 to further correct the engine starting voltage Vst1, or in the second aspect, the engine starting voltage correcting means has a one-to-one correspondence with the battery temperature measured by the battery temperature measuring means. If the engine starting voltage Vst1 is further corrected by adding the correction amount corresponding to the above to the engine starting voltage Vst1, the influence of the battery temperature is also eliminated, so that the battery state of the battery can be determined with higher accuracy.

According to the present invention, the engine starting voltage Vst1 obtained by correcting the engine starting voltage Vst in consideration of the influence of the vehicle temperature is calculated by the engine starting voltage correcting means, and the engine starting voltage Vst1 is calculated by the battery state determining means. Since it is determined whether or not Vst_th or more, the influence of the temperature of the vehicle is eliminated in determining the battery state, so that the battery state of the battery can be accurately determined , and the open circuit voltage measuring means can detect the dark current from the battery. A stable open circuit voltage OCV when the engine is flowing is measured, and the engine starting voltage correcting means and the determination voltage calculating means add a correction amount that is a function of temperature to the open circuit voltage OCV measured by the open circuit voltage measuring means. The engine start voltage Vst1 and the battery determination voltage Vs using the corrected open circuit voltage OCV1 obtained by adding For calculating the - th, since the open circuit voltage OCV is also the temperature correction can be determined more accurate battery state of the battery, the effect can be obtained as.

  Hereinafter, an embodiment in which the present invention is applied to a battery state determination apparatus that determines a battery state of a lead battery mounted on a gasoline vehicle will be described with reference to the drawings.

(Constitution)
As shown in FIG. 1, the battery state determination device 12 of the present embodiment 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 measures the voltage across the lead battery 1. A microcomputer (hereinafter referred to as a microcomputer) 10 for determining the battery state of the voltage sensor 3 and the lead battery 1 is provided.

  The lead battery 1 has a rectangular battery case serving as a battery container. The battery case material is excellent in terms of moldability, electrical insulation, corrosion resistance and durability, for example, polymer resins such as acrylic butadiene styrene (ABS), polypropylene (PP), polyethylene (PE), etc. Can be selected. A sensor insertion hole is formed in the partition wall at the center of the battery case. The temperature sensor 2 is inserted into the sensor insertion hole, and is fixed in the sensor insertion hole with an adhesive. A total of six sets of electrode plates are accommodated in the battery case. In each electrode plate group, a plurality of negative electrode plates and positive electrode plates are laminated via a retainer (separator) made of glass fiber, and the cell voltage is set to 2.0V. Therefore, the nominal voltage of the lead battery 1 is 12V. The upper part of the battery case is bonded or welded to an upper lid made of a polymer resin such as ABS, PP, PE or the like that seals the upper opening of the battery case. A rod-shaped positive external output terminal and a negative external output terminal for supplying electric power to the outside using a lead battery as a power source are erected on the upper lid.

  The positive external output terminal of the lead battery 1 described above is connected to the center terminal of an ignition switch (hereinafter referred to as IGN switch) 5. The IGN switch 5 has an OFF terminal, an ON / ACC terminal, and a START terminal in addition to the central terminal, and the central terminal and any of these OFF, ON / ACC, and START terminals can be switched in a rotary manner. Is possible.

  The START terminal is connected to an engine starting cell motor (engine starting 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 connected to one end of a generator 7 that generates electric power by rotation of the engine 8 through an auxiliary device 6 such as an air conditioner, a radio, a lamp, etc. and a diode that allows current flow in one direction. . That is, the anode of the diode is connected to one end of the generator 7, and the cathode 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.

  An external output terminal of the lead battery 1 is connected to the voltage sensor 3, and an output side of the voltage sensor 3 is connected to an A / D converter built in the microcomputer 10. For this reason, the microcomputer 10 can take in the voltage of the lead battery 1 as a digital value. The output terminal of the temperature sensor 2 is connected to an A / D converter built in the microcomputer 10. For this reason, the microcomputer 10 can capture the temperature of the lead battery 1 as a digital value. The microcomputer 11 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 ROM that stores program data such as a basic control program of the battery state determination device 12 and maps and mathematical expressions described later, and a work area of the CPU and temporarily stores data. It includes a RAM and the like for storing. A non-volatile memory such as an EEPROM (not shown) is connected to the external bus of the microcomputer 10. The other end of the generator 7, the cell motor 9 and the auxiliary machine 6, the negative external output terminal of the lead battery 1, and the microcomputer are each connected to the ground. Note that the microcomputer 10 of the present embodiment samples the voltage and temperature at 1-msec intervals and stores the sampling result in the RAM.

(Operation)
Next, with reference to a flowchart, the operation of the battery state determination device 12 of the present embodiment will be described with the CPU of the microcomputer 10 as a main component. When the microcomputer 10 is powered on, the CPU executes a battery state determination routine for determining the battery state of the lead battery 1 shown in FIG. The program and program data stored in the ROM are expanded in the RAM by an initial setting process (not shown) after turning on the power to the microcomputer 10.

  As shown in FIG. 2, in the battery state determination routine, in step 102, the discharge polarization is accumulated while the lead battery 1 is being discharged (during driving of the vehicle), so that the polarization is not released. Wait until the voltage of the lead battery 1 is stabilized. That is, it is determined that the voltage of the lead battery 1 is stable by determining whether a predetermined time (for example, 6 hours) has elapsed after the engine is stopped. Whether the engine 8 has stopped may be notified from the vehicle control system 11, for example, or the microcomputer 10 may determine whether the engine has stopped by monitoring the voltage of the lead battery 1 measured by the voltage sensor 3. It may be.

  In the next step 104, the open circuit voltage OCV of the lead battery 1 is measured. That is, the voltage of the lead battery 1 output from the voltage sensor 3 is captured as a digital value via the A / D converter. Next, in step 106, the temperature of the lead battery 1 output from the temperature sensor 2 is acquired as a digital value via the A / D converter, and as shown in FIG. 4, the measured open circuit voltage OCV is measured according to the temperature correction map. A corrected open circuit voltage OCV1 obtained by adding a correction amount which is a temperature correction function is calculated. Since the dark current flows through the lead battery 1 even when the engine is stopped, the voltage of the lead battery 1 is lower than the actual open circuit voltage OCV. The lower the temperature, the more the difference from the actual open circuit voltage OCV is. growing. Therefore, in step 106, the open circuit voltage OCV1 of the lead battery 1 is added to the temperature correction amount shown in FIG. Such a temperature correction map is desirably changed according to battery design, battery deterioration, and vehicle dark current. In the case where the dark current cannot be known, as shown in FIG. 4, if a correction map assumed for a dark current of 10 to 20 mA is used, good results can be obtained in many vehicles.

  Next, at step 108, it is determined whether or not the engine is first started after the voltage of the lead battery 1 is stabilized. When the determination is negative, the process returns to step 102, and when the determination is affirmative, the engine start voltage Vst is measured at step 110. As described above, since the microcomputer 10 stores the voltage of the lead battery 1 at the time of engine start in the RAM sampled at an interval of 1 msec, the voltage value stored in the RAM falls below a certain value (for example, 9V). In this case, the minimum value can be determined as the engine start voltage Vst.

  In the next step 112, the engine start voltage Vst1 corrected from the engine start voltage Vst is calculated based on the open circuit voltage OCV corrected in step 106 and the vehicle temperature. Here, the calculation significance and calculation formula of the engine start voltage Vst1 will be described in detail.

  The voltage at the time of starting the engine shown in FIG. 6 depends on the electrical resistance and mechanical resistance of the vehicle, both of which are affected by temperature. The temperature dependence of the mechanical resistance is difficult to predict, but the electrical resistance can be predicted by assuming the material of the conductor. It is possible to eliminate the influence of mechanical resistance by using the engine start voltage Vst (the engine start voltage Vst measured in step 110) when the first large voltage drop that the piston seems to have hardly started moving is possible. It is. Further, by correcting the engine starting voltage Vst to a value at a reference temperature (for example, 25 ° C. of room temperature) by the following equation (1), it is possible to eliminate the influence of the electric resistance on the voltage.

  In the equation (1), OCV is the open circuit voltage (OCV1) subjected to temperature correction in step 106, T is the temperature of the vehicle (for example, the cell motor 9), T0 is the reference temperature described above, and A is 0.9 to 1.. A constant taking a range of 1 (set to 1.0 in this example), α is a temperature correction coefficient for correcting the electric resistance of the vehicle at the time of engine start to a value at T0. For the temperature correction coefficient α, for example, a good correction can be expected by using a value of an annealed copper wire (JIS C3102).

  As shown in FIG. 1, it is desirable that the temperature of the cell motor 9 is originally measured by the temperature sensor 4 as shown in FIG. 1. However, if sufficient time elapses after the engine is stopped, the temperature of the cell motor 9 and the surrounding vehicle parts are In this embodiment, it is determined whether a sufficiently long specified time has elapsed since the previous engine stop (in this example, 6 hours have been determined in step 102), and the engine is stopped or the engine is started. Immediately after that, the temperature of the lead battery 1 is measured (see step 106) and used as the temperature T of the vehicle.

  Next, at step 114, the engine starting voltage Vst1 is further corrected in consideration of the temperature dependence of the battery characteristics. As shown in FIG. 5, this correction is performed by adding the temperature correction amount to the engine start voltage Vst1 using the temperature correction map. The temperature correction map shown in FIG. 5 varies depending on the lead battery used. Discharge voltage is a function of current and temperature characteristics are slightly different, so in the case of a battery status determination device (with a current sensor) where current information can be obtained, accuracy is further improved by specifying a temperature correction amount for each current Can be made. Actually, since the temperature correction coefficient does not differ greatly depending on the inrush current of 500 to 900 A at the time of engine start in a normal automobile, a battery state determination device that can withstand practical use can be realized without adding a current sensor.

  In the next step 116, it is determined whether or not the number of engine starts is less than 5 and the open circuit voltage OCV exceeds 12.5V. In other words, it is determined whether or not the lead battery 1 is not deteriorated (new) and is fully charged. If the determination is affirmative, in step 118, the engine start voltage Vst0 when the lead battery 1 is not deteriorated and fully charged is calculated by the following equation (4) and stored in the EEPROM. In other words, the engine starting voltage Vst0 is a voltage at the time of starting the engine at an open circuit voltage OCV0 (12.4V ≦ OCV0 ≦ 13.0V) in a non-deteriorated (new) and fully charged state.

  In step 116, the engine starting voltage Vst0 already stored in the EEPROM is read out, an average value of the engine starting voltage Vst0 is calculated, and stored in the EEPROM. For this reason, finally, the average value of the engine start voltage Vst0 when the lead battery 1 is not deteriorated and fully charged a plurality of times is calculated and stored in the EEPROM.

  Next, at step 120, (r0 / R) when the internal resistance at the open circuit voltage OCV0 of the lead battery 1 in the non-degraded and fully charged state is r0 and the electric resistance R of the vehicle is expressed by the following equation (3). Calculate and store in EEPROM. In step 120, (r0 / R) already stored in the EEPROM is read out, an average value of (r0 / R) is calculated, and stored in the EEPROM. For this reason, finally, the average value of (r0 / R) in the non-degraded and fully charged state of the lead battery 1 a plurality of times is calculated and stored in the EEPROM.

  Next, in step 122, the lead battery 1 when the increase rate of the internal resistance of the lead battery 1 reaches a predetermined value for battery replacement from the open circuit voltage corrected in temperature in step 106 by the following equation (2). The battery determination voltage Vst_th representing the voltage at the time of engine start is calculated. The average values of the engine starting voltages Vst0 and (r0 / R) calculated in steps 118 and 120 are read from the EEPROM and substituted into the equation (2). In equation (2), OCV is the open circuit voltage (OCV1) that has been temperature-corrected in step 106, r_th is the internal resistance threshold value of the battery for battery replacement, and B is 0.9 to 1.1. A constant that takes a range (set to 1.0 in this example) and (r_th / r0) are set to a constant in the range of 1.2 to 1.6 (1.4 in this example). ), That is, the increase rate of the internal resistance of the new lead battery 1.

  Here, the relationship of Formula (2)-(4) is demonstrated. Expression (2) includes the electric resistance R of the vehicle. Although it is theoretically possible to actually measure the electric resistance R of a different vehicle for each vehicle type and write it in the ROM or EEPROM, it is difficult as a commercial problem. On the other hand, (r0 / R) can be calculated by equation (3). In Formula (3), Vst0 is Vst (OCst1 in this example) when OCV = OCV0. Actually, the OCV at the time of Vst acquisition is unlikely to become OCV0 conveniently, so it is corrected to Vst0 at OCV0 by equation (4), and equations (4) and (3) are substituted into equation (2). Thus, the battery determination voltage Vst_th can be calculated even without knowing the electric resistance R of the vehicle.

  In step 124, in order to prepare for the determination in step 116, the number of engine start is counted, and in the next step 126, it is determined whether or not the engine start voltage Vst1 is equal to or higher than the battery determination voltage Vst_th. The comparison between the engine start voltage Vst and the battery determination voltage Vst_th indicates that the increase rate (r_th / r0) of the internal resistance from the new product is a predetermined value, as can be seen from the form of equation (2) defining the battery determination voltage Vst_th. Is equivalent to determining whether or not. As described above, the increase rate (r_th / r0) of the internal resistance of the new lead battery 1 is set to a constant within the range of 1.2 to 1.6 (1.4 in this example). If it is less than the range, a warning may be issued within the warranty period even with a normal battery. If this range is exceeded, there is a possibility that the engine cannot be started before issuing the warning to the vehicle control system 11 side. Since the internal resistance is a function of the state of charge, the internal resistance threshold r_th when issuing a warning is defined as a function of the open circuit voltage OCV.

  If the determination in step 126 is affirmative, the vehicle control system 11 is informed in step 128 that the battery state of the lead battery 1 is good, and if the determination is negative, the vehicle control system 11 is notified in step 130 to the lead battery. 1 (warning) that it is necessary to replace 1 is notified and the battery state determination routine is terminated. 2 shows an example in which the battery state determination routine is ended by the processing in steps 128 and 130 for the sake of simplicity, but actually the process returns to step 102 and the battery state of the lead battery 1 is shown. Continue the determination.

  The vehicle control system 11 informed that the replacement of the lead battery 1 is required causes the instrument panel to display that the replacement of the lead battery 1 is necessary. As a result, the driver recognizes that the lead battery 1 needs to be replaced, and the lead battery 1 can be replaced at a vehicle service station or the like. The vehicle control system 11 may display on the installation panel that the battery state of the lead battery 1 is good.

(Action etc.)
Next, operations, effects, and the like of the battery state determination device 12 of the present embodiment will be described.

  In the battery state determination device 12 of the present embodiment, the engine start voltage Vst1 obtained by correcting the engine start voltage Vst in consideration of the influence of the vehicle temperature is calculated by the equation (1) (step 112), and the engine start voltage Vst1 is calculated. Since it is determined whether or not the battery determination voltage Vst_th or higher for determining the replacement of the lead battery 1 (step 126), the erroneous determination due to the influence of the vehicle temperature is eliminated in the replacement determination due to the deterioration of the lead battery 1. The battery state of the lead battery 1 can be accurately determined. Therefore, the so-called engine stall at the time of idling stop / start can be prevented.

  Further, in the battery state determination device 12 of this embodiment, the temperature of the lead battery 1 measured after elapse of a predetermined time (for example, 6 hours) or more from the engine stop is regarded as the temperature of the vehicle, and the engine is calculated according to the equation (1). Since the starting voltage Vst1 is calculated, it is not necessary to directly measure the temperature of the vehicle such as the cell motor 9 as described above, so that it is possible to save a lot of time and effort when mounting (particularly, retrofitting) the battery state determination device. In addition, the length of the lead wire from the cell motor 9 to the battery state determination device 12 can be shortened, and the influence of errors due to noise or the like can be reduced.

  Furthermore, in the battery state determination device 12 of the present embodiment, as shown in FIG. 4, the corrected open circuit voltage OCV1 obtained by adding a correction amount that is a temperature correction function to the measured open circuit voltage OCV. Is calculated (step 106), and the engine start voltage Vst1 and the battery determination voltage Vst_th are calculated using the corrected open circuit voltage OCV1 using the equations (1) and (2) (steps 112 and 122). For this reason, the battery state determination device 12 can more accurately determine the battery state of the lead battery 1. Further, in the battery state determination device 12 of the present embodiment, as shown in FIG. 5, the temperature of the lead battery 1 and the correction amount corresponding to one body 1 are added to the engine starting voltage Vst1 to further increase the engine starting voltage Vst1. It is corrected. For this reason, the battery state of the lead battery 1 can be determined more accurately.

  In the present embodiment, an example in which the engine starting voltage Vst1 is calculated by regarding the temperature of the lead battery 1 after a predetermined time or more from the engine stop as the temperature of the vehicle is shown, but the present invention is not limited to this. As shown in FIG. 1, a temperature sensor 4 that actually measures the temperature of the cell motor 9 (vehicle) may be provided. In this embodiment, the correction amount map corresponding to the temperature is illustrated in FIGS. 4 and 5. However, the present invention is not limited to this, and a relational expression representing the relationship between the temperature and the correction amount is used. May be.

  Furthermore, in this embodiment, although the example which set the constants A and B to 1.0 in Formula (1), (2) was shown, the specification of the lead battery 1 and the lead battery 1 are mounted in these constants. Depending on the vehicle, the value may be changed to an appropriate value in the range of 0.9 to 1.1. In the present embodiment, the temperature measurement interval by the temperature sensor 3 is 1 ms, which is the same as the voltage measurement interval. However, the temperature change is not steep as shown in FIG. It is also possible to measure at intervals longer than the measurement interval, store the measurement results in the RAM, and use the latest measurement temperature.

  Furthermore, in the present embodiment, in steps 126 to 130, the battery state of the lead battery 1 is good, and an example of one-step determination of replacement is shown, but instead of this, Vst ≧ Vst_th1 ((r_th / r0) is set to 1.3, for example.) is determined to be good when affirmative, and Vst ≧ Vst_th2 (when (r_th / r0) at this time is, for example, In other words, a two-step determination may be performed in which an affirmative determination determines that a state of caution is required and a negative determination indicates replacement is required.

  Next, an example of a battery state determination device that determines the battery state of 65B24 mounted on a 2000 cc gasoline vehicle according to the above embodiment will be described. In addition, the battery state determination apparatus produced for the comparison is also demonstrated.

Example 1
After starting the engine 5 times at intervals of 6 hours, a gasoline car was put in a low temperature constant temperature room and the engine was started at temperatures of 0 ° C. and −10 ° C. We used an in-circuit emulator that can check the internal variables of the battery status determination device. When the engine starting voltage Vst1 after temperature correction was confirmed, the values shown in Table 1 below were obtained. It can be seen that the temperature correction is sufficiently accurate.

(Comparative Example 1)
In the battery state determination apparatus of Comparative Example 1, as shown in FIG. 3, the same test as the battery state determination apparatus of Example 1 was performed without performing vehicle temperature correction and open circuit voltage temperature correction. That is, the flowchart of FIG. 3 lacks the processing of steps 106 and 112 of the flowchart of FIG. The test results are shown in Table 1. The battery state determination device of Comparative Example 1 has a larger temperature correction error than the battery state determination device of Example 1. This result shows that the battery state determination apparatus of Example 1 is superior in terms of battery state determination.

  Since the present invention provides a battery state determination device that can accurately calculate the battery state of the battery from the engine starting voltage in consideration of the influence of the temperature of the vehicle, it contributes to the manufacture and sale of the battery state determination device. Has industrial applicability.

1 is a block wiring diagram of a battery state determination device and a vehicle according to an embodiment to which the present invention is applicable. It is a flowchart of the battery state determination routine which CPU of the microcomputer of the battery state determination apparatus of embodiment performs. It is a flowchart of the battery state determination routine which CPU of the microcomputer of the battery state determination apparatus of the comparative example 1 performs. It is a map which shows the temperature correction amount of the open circuit voltage of the lead battery at the time of dark current energization. It is a map which shows the temperature correction amount of the engine starting voltage Vst1. It is a graph which shows the voltage change of the lead battery at the time of engine starting.

Explanation of symbols

1 Lead battery (battery)
2 Temperature sensor (part of battery temperature measurement means)
3 Voltage sensor (part of open circuit voltage measurement means, part of engine starting voltage measurement means)
4 Temperature sensor (part of vehicle temperature measurement means)
10 microcomputer (engine starting voltage correction means, determination voltage calculation means, battery state determination means)
12 Battery state determination device

Claims (10)

In a battery state determination device for determining a battery state of a battery mounted on a vehicle,
Open circuit voltage measuring means for measuring the open circuit voltage OCV of the battery;
Engine starting voltage measuring means for measuring an engine starting voltage Vst representing a voltage at the time of starting the engine of the battery;
Vehicle temperature measuring means for measuring the temperature of the vehicle;
Based on the open circuit voltage OCV measured by the open circuit voltage measuring means and the vehicle temperature measured by the vehicle temperature measuring means, the engine start is corrected by correcting the engine start voltage Vst measured by the engine start voltage measuring means. Engine starting voltage correcting means for calculating the voltage Vst1,
A battery determination voltage Vst_th representing a voltage at the time of starting the engine of the battery when the increase rate of the internal resistance of the battery reaches a predetermined value for battery replacement from the open circuit voltage OCV measured by the open circuit voltage measuring means Determination voltage calculation means for calculating
Battery state determination means for determining whether the engine start voltage Vst1 calculated by the engine start voltage correction means is equal to or higher than the battery determination voltage Vst_th measured by the determination voltage calculation means;
The open circuit voltage measuring means measures a stable open circuit voltage OCV when dark current is flowing from the battery, and the engine starting voltage correcting means and the determination voltage calculating means are the open circuit voltage The engine start voltage Vst1 and the battery determination voltage Vst_th are calculated using the corrected open circuit voltage OCV1 obtained by adding a correction amount that is a function of temperature to the open circuit voltage OCV measured by the measuring means. A battery state determination device. In a battery state determination device for determining a battery state of a battery mounted on a vehicle,
Open circuit voltage measuring means for measuring the open circuit voltage OCV of the battery;
Engine starting voltage measuring means for measuring an engine starting voltage Vst representing a voltage at the time of starting the engine of the battery;
Battery temperature measuring means for measuring the temperature of the battery;
Engine start voltage correction for calculating an engine start voltage Vst1 obtained by correcting the engine start voltage Vst measured by the engine start voltage measurement means based on the open circuit voltage OCV measured by the open circuit voltage measurement means and the vehicle temperature. Means,
A battery determination voltage Vst_th representing a voltage at the time of starting the engine of the battery when the increase rate of the internal resistance of the battery reaches a predetermined value for battery replacement from the open circuit voltage OCV measured by the open circuit voltage measuring means Determination voltage calculation means for calculating
Battery state determination means for determining whether the engine start voltage Vst1 calculated by the engine start voltage correction means is equal to or higher than the battery determination voltage Vst_th measured by the determination voltage calculation means;
The open circuit voltage measuring means measures a stable open circuit voltage OCV when dark current is flowing from the battery, and the engine starting voltage correcting means and the determination voltage calculating means are the open circuit voltage The engine start voltage Vst1 and the battery determination voltage Vst_th are calculated using the corrected open circuit voltage OCV1 obtained by adding a correction amount that is a function of temperature to the open circuit voltage OCV measured by the measuring means, The battery is characterized in that the engine starting voltage correcting means calculates the engine starting voltage Vst1 by regarding the temperature of the battery measured by the battery temperature measuring means as a temperature of the vehicle after a predetermined time or more has elapsed since the engine stopped. State determination device. The engine start voltage correction means is a temperature correction coefficient for correcting the temperature of the vehicle to T, the reference temperature for temperature correction to T0, and the electric resistance of the vehicle at the time of engine start to a value at the reference temperature T0. The battery according to claim 1 or 2, wherein the engine starting voltage Vst1 is calculated by the following formula (1), where A is a constant taking a range of 0.9 to 1.1. State determination device.

  4. The battery state determination apparatus according to claim 3, wherein the temperature correction coefficient α is a temperature correction coefficient of electrical resistance of a copper wire. The determination voltage calculation means has an internal resistance r0 at the open circuit voltage OCV = OCV0 (12.4V ≦ OCV0 ≦ 13.0V) of a new battery, r_th as an internal resistance threshold value of the battery for battery replacement, The battery determination voltage Vst_th is calculated by the following equation (2), where R is the electric resistance of the vehicle and B is a constant taking a range of 0.9 to 1.1. Item 3. The battery state determination device according to Item 2.

  6. The battery state determination device according to claim 5, wherein the determination voltage calculation means calculates (r_th / r0) of the equation (2) as a constant within a range of 1.3 to 1.6. The determination voltage calculation means sets (r0 / R) in the equation (2) to the following equation (3) when the engine start voltage Vst when the open circuit voltage OCV of a new battery takes the OCV0 is Vst0. The battery state determination device according to claim 5, wherein the battery state determination device calculates the battery state.

The battery state determination device according to claim 7, wherein the determination voltage calculation means calculates the engine start voltage Vst0 of the equation (3) by the following equation (4).

  Battery temperature measuring means for measuring the temperature of the battery is further provided, and the engine starting voltage correcting means has a correction amount corresponding to the battery temperature measured by the battery temperature measuring means in a one-to-one relationship with the engine starting voltage Vst1. The battery state determination device according to claim 1, wherein the engine start voltage Vst1 is further corrected by adding to the above.   The engine start voltage correcting means further adds the correction amount corresponding to the battery temperature measured by the battery temperature measuring means to the engine start voltage Vst1 to further correct the engine start voltage Vst1. The battery state determination apparatus according to claim 2, wherein the apparatus is a battery state determination apparatus.

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