JP4677970B2 - Battery state determination device and lead battery for automobile - Google Patents

Description

  The present invention relates to a battery state determination device and a lead battery for an automobile, and more particularly to a battery state determination device for determining a health state of a lead battery and an automotive lead battery including the battery state determination device.

  In general, a lead battery for starting an internal combustion engine is mounted on an automobile, and such a lead battery is called a lead battery for an automobile or a vehicle. The lead battery for automobiles is an extremely important component from the viewpoint of ensuring the start of the automobile. Therefore, detecting the battery state of the lead battery for automobiles is useful in the sense of, for example, predicting or guaranteeing restart of the internal combustion engine after the automobile has stopped.

  For this reason, conventionally, attempts have been made to detect the battery state by measuring the open circuit voltage of an automotive lead battery, measuring the internal resistance using an alternating current, and measuring the charge current, discharge current and discharge voltage together. . As a specific example, there is disclosed a remaining capacity detecting device that prepares a relationship between the voltage and current of a lead battery in advance and detects the remaining capacity of the lead battery in comparison with data obtained by actual measurement. (For example, refer to Patent Document 1). In addition, when an alternating current is applied and the internal resistance exceeds a certain value, a correlation equation between the internal resistance and the remaining capacity is obtained, and based on this, the remaining capacity of the lead battery is monitored and the lifetime is estimated. A technique is disclosed (for example, see Patent Document 2). Furthermore, a technology for obtaining the internal resistance of a lead battery from an open circuit voltage and a discharge voltage without using a current sensor and detecting the health condition of the lead battery from a predetermined relationship between the internal resistance and SOH is disclosed. (For example, see Patent Document 3). In such a battery state detection device, in general, it is determined whether or not the lead battery has deteriorated enough to be replaced, using a determination threshold value that is a criterion for deterioration determination.

JP-A-7-63830 JP 2002-334725 A JP-A-2005-304173

  By the way, in order to determine the health state of a lead battery only by measuring the voltage of the lead battery without using a current sensor, the lead battery engine in an undegraded state where the open circuit voltage of the lead battery before starting the engine is above a certain value. Whether or not the voltage difference or ratio between the minimum voltage value at the start and the current minimum voltage value at the start of the lead battery engine (in a non-degraded or deteriorated state) is greater than a determination threshold for determining deterioration It is conceivable to determine the health state (deterioration state). However, for example, if the lead-acid battery has a long over-the-counter inventory period and the lead battery seems to be discharged, and the driver is a so-called weekend driver, and the driver rarely drives the car, the open circuit voltage is above a certain value. It is assumed that the minimum voltage value at the time of engine start of the lead battery in the non-degraded state cannot be obtained. It is considered that the lead battery is substantially in a non-degraded state for about half a year from the time when it is installed in a car (beginning of use). As a result, the health condition of the lead battery cannot be determined.

  This invention makes it a subject to provide the battery state determination apparatus which can determine the health condition of a lead battery exactly, without using a current sensor, and the lead battery for motor vehicles provided with this battery state determination apparatus in view of the said case. .

  In order to solve the above-mentioned problem, a first aspect of the present invention is a battery state determination device for determining a health state of a lead battery for an automobile, wherein the voltage measurement unit measures the voltage of the lead battery, and the voltage measurement unit. Vst calculating means for calculating the minimum voltage value Vst at the time of starting the engine of the lead battery from the voltage measured in step (b), determining whether the minimum voltage value Vst calculated by the Vst calculating means satisfies a predetermined condition, Vst0 storage means for storing the lowest voltage value Vst in the memory as the lowest voltage value Vst0 at the time of starting the engine in the non-degraded state of the lead battery when it is determined that it is satisfied, and stored in the memory by the Vst0 storage means From the lowest voltage value Vst0 and the latest lowest voltage value Vst calculated by the Vst calculation means in the non-degraded state or the deteriorated state of the lead battery, the lead battery State determination means for determining a state of rest, wherein the Vst0 storage means at least sets the minimum voltage value Vst at the time of initial engine start of the lead battery even if the minimum voltage value Vst is determined not to satisfy the predetermined condition. A temporary value of the voltage value Vst0 is stored in the memory.

  In this aspect, the voltage of the lead battery is measured by the voltage measuring means, and the minimum voltage value Vst at the time of starting the engine of the lead battery is calculated from the voltage measured by the voltage measuring means by the Vst calculating means. The Vst0 storage means determines whether or not the minimum voltage value Vst satisfies a predetermined condition. When it is determined that the minimum voltage value Vst satisfies the minimum voltage value Vst, the minimum voltage value Vst is the minimum voltage value at the start of the engine when the lead battery is not deteriorated. Vst0 is stored in the memory. As this predetermined condition, for example, it can be assumed that the open circuit voltage of the lead battery before starting the engine is greater than or equal to a predetermined voltage value after the lead battery is attached to the automobile. Then, the health of the lead battery is calculated from the minimum voltage value Vst0 stored in the memory by the Vst0 storage means and the latest minimum voltage value Vst calculated by the Vst calculation means when the lead battery is not deteriorated or deteriorated by the state determination means. The state is determined. As described above, in order for the state determination unit to determine the health state of the lead battery, it is assumed that the minimum voltage value Vst0 is acquired by the Vst0 storage unit. However, the Vst0 storage unit satisfies the predetermined condition for the minimum voltage value Vst. Otherwise, the minimum voltage value Vst0 is not acquired, and if the minimum voltage value Vst0 is not acquired, the health determination by the state determination unit is not performed. For this reason, in this aspect, even if the Vst0 storage means determines that at least the lowest voltage value Vst at the time of the first engine start of the lead battery does not satisfy the predetermined condition, it is stored in the memory as a temporary value of the lowest voltage value Vst0. By storing and using the provisional value by the state determination means, the state determination means can always determine the health condition of the lead battery. According to this aspect, since the state determination means determines the health state of the lead battery from the lowest voltage value calculated in the non-degraded state of the lead battery and the latest lowest voltage value, the lead is used without using a current sensor. Even when the health state of the battery can be determined and the Vst0 storage means determines that at least the minimum voltage value Vst at the start of the first engine of the lead battery does not satisfy the predetermined condition, the lead battery has no deterioration state Is stored in the memory as a provisional value of the lowest voltage value Vst0 at the time of engine start, so that it is always possible to determine the health state by the state determination means.

  In this embodiment, assuming that supply of operating power to the battery state detection device is interrupted, the memory is a non-volatile memory so as not to lose data of the lowest voltage value Vst0 that can be acquired only in the non-degraded state. Preferably, in order to reduce the capacity of this memory from the viewpoint of cost and the like, the Vst0 storage means determines whether or not a temporary value is stored when storing the minimum voltage value Vst0 in the memory. At the time of determination, it is preferable to replace the temporary value with the minimum voltage value Vst0. The Vst0 storage means stores a plurality of minimum voltage values Vst0 in the memory, and the state determination means stores the closest average value, mode value, or median value of the plurality of minimum voltage values Vst0 stored in the memory. If the health state of the lead battery is determined from the minimum voltage value Vst using the determination threshold value, variation in the minimum voltage value Vst0 can be prevented, and the state of health of the lead battery by the state determination means can be prevented. The determination accuracy can be increased. Further, in order to distinguish between the discharge of the lead battery due to the engine start and the discharge to the in-vehicle electrical components such as the car air conditioner and the car navigation, the Vst calculating means determines the predetermined time from the voltage of the lead battery measured by the voltage measuring means. Within X (X: 1 to 100 ms), there is a voltage drop of a predetermined voltage Y (Y: 0.5 to 3.0 V) or more, and then a predetermined value a (a: 109% of the open circuit voltage of the lead battery) It is preferable to determine whether or not the voltage value is equal to or higher than the above, and calculate the minimum voltage value Vst when an affirmative determination is made and not calculate the minimum voltage value Vst when a negative determination is made.

  Moreover, in order to solve the said subject, the 2nd aspect of this invention is the lead battery for motor vehicles provided with the battery state determination apparatus of the 1st aspect. The lead battery for automobiles according to the second aspect also has the same operational effects as the first aspect.

  According to the present invention, the state determination means determines the health state of the lead battery from the lowest voltage value calculated in the non-degraded state of the lead battery and the latest lowest voltage value. Even when the health state of the battery can be determined and the Vst0 storage means determines that at least the minimum voltage value Vst at the start of the first engine of the lead battery does not satisfy the predetermined condition, the lead battery has no deterioration state Since it is stored in the memory as a temporary value of the minimum voltage value Vst0 at the time of starting the engine, it is possible to obtain the effect that the health judgment can always be made by the state judging means.

  Hereinafter, an embodiment in which the present invention is applied to an automotive lead battery (model: 65B24R) will be described with reference to the drawings.

(Constitution)
As shown in FIG. 1, the lead battery 10 of the present embodiment has a substantially rectangular battery case 8 serving as a battery container, and a total of six electrode plate groups are accommodated in the battery case 8. Yes. As the material of the battery case 8, it is possible to select a polymer resin such as polyethylene (PE), polypropylene (PP), and acrylic butadiene styrene (ABS) that is excellent in terms of formability, insulation, durability, and the like. it can. In each electrode plate group, a plurality of negative electrodes and positive electrodes are laminated via a separator, and the cell voltage is set to 2.0V. Therefore, the nominal voltage of the lead battery 10 is 12V. The upper part of the battery case 8 is bonded or welded to an upper lid 9 made of a polymer resin such as PE that seals the upper opening of the battery case 8.

  The upper lid 9 is provided with two (positive and negative) output terminals 7 for supplying electric power to the outside by using the lead battery 10 as an automobile power source. In addition, the upper lid 9 houses (incorporates) an AI unit 1 as a battery state determination device that determines the health state of the lead battery 10.

  The AI unit 1 is composed of an AD converter, a reference power source, etc., and measures a voltage of the lead battery 10, a temperature measuring unit, which is composed of an AD converter, a thermistor, etc., and measures the temperature of the lead battery 10, and a microprocessor , ROM, RAM, nonvolatile memory EEPROM, etc., a coil-type buzzer (not shown), a transistor for operating the buzzer, resistors, etc. A notification unit to be generated, an operation display unit configured to include an operation button 3, a light emitting diode (hereinafter referred to as an LED), a transistor, a resistor, and the like, and turn on the LED to indicate that the lead battery 10 needs to be replaced. 2 are provided. The AI unit 1 is connected to the output terminal 7 by a connecting conductor in the upper lid 9, and operating power is supplied from the lead battery 10.

  A buzzer sound emitting hole 6 is formed at a position where the buzzer of the AI unit 1 is mounted on the upper lid 9, and the upper surface of the operation display unit 2 of the AI unit 1 is substantially flush with the upper surface of the upper lid 9. .

(Degradation judgment principle)
Next, the principle of determining deterioration (health state) of the lead battery 10 by the AI unit 1 will be described.

  The microprocessor (hereinafter abbreviated as MP) captures the digital voltage value of the lead battery 10 via the voltage measurement unit and stores it in the RAM every predetermined time (for example, 2 ms). The health condition of the lead battery 10 is determined based on the above.

  In general, in an automobile having an internal combustion engine such as a gasoline engine vehicle or a diesel engine vehicle, 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 greatly drops. When the voltage drop at this time and the time change of the current 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, between the terminals of the lead battery as shown in FIGS. The voltage shows a sharp valley-like voltage drop. The minimum voltage value Vst at which this voltage drop is maximum appears simultaneously at the maximum current value Ist at which the discharge current from the lead battery is maximum.

  Assuming that the engine starting system electrical resistance is R, Ohm's law is established as shown in the following formula (1) at the timing when the minimum voltage value Vst and the maximum current value Ist appear.

  The engine starting system electric resistance R is the resistance of the engine starting system constituted by a cell motor, a harness, etc. at the time of starting the engine. The total resistance obtained by adding the resistance of the cell motor as a stationary conductor to the resistance of the vehicle harness, electric contact, etc. It is. It should be noted that the engine starting system electric resistance R is a constant value only at the timing when the minimum voltage value Vst is taken, and at other timings, the engine starting system electric resistance R changes with time. Not satisfied.

  In other words, if the vehicle is the same, if the engine starting voltage can be acquired at the timing of the lowest voltage value Vst, the engine starting system electric resistance R itself is a constant with a constant resistance value using the formula (1). This resistor can be used to judge deterioration of lead batteries.

  On the other hand, when the open circuit voltage of the lead battery is Vo and the internal resistance of the lead battery is r at the timing when the minimum voltage value Vst and the maximum current value Ist appear, the following equation (2) is established.

  By substituting equation (1) into equation (2), the following equation (3) is obtained.

  From equation (3), it can be seen that the minimum voltage value Vst is a function of the open circuit voltage Vo, the engine starting system electrical resistance R, and the internal resistance r of the lead battery. The internal resistance r shows the minimum value in the non-degraded state of the lead battery, and increases as the health state (SOH) decreases. Therefore, from Equation (3), the minimum voltage value Vst is an indicator of the health status of the lead battery. In other words, when the health state of the lead battery is reduced (when the lead battery is deteriorated), the internal resistance r is increased, so that the minimum voltage value Vst is lowered.

  FIG. 6 shows the transition of the terminal voltage of the lead battery at the time of starting the engine for the lead battery in an undegraded state (initial state) and the same lead battery after deterioration. In FIG. 6, the lowest voltage value at the time of starting the engine of the lead battery in the non-degraded state is represented by Vst0, and the lowest voltage value at the time of starting the engine after deterioration is represented by Vst. In FIG. 6, as the lead battery deteriorates, the voltage difference ΔVst (= Vst0−Vst) between the lowest voltage value Vst0 in the non-degraded state and the lowest voltage value Vst after deterioration increases.

  In accordance with the above principle, the AI unit 1 determines that the lead battery 10 has deteriorated and has reached a required replacement state when the voltage difference ΔVst becomes larger than a determination threshold value Vth described later. However, as described above, in order to use the above principle (Equation (1)), it is assumed that the minimum voltage values Vst0 and Vst at the time of starting the engine are accurately obtained. Therefore, the minimum voltage values Vst0 and Vst Need to be acquired at the optimal timing.

(Engine condition judgment)
The AI unit 1 also has a function of detecting the engine state based on the voltage of the lead battery 10 measured through the voltage measuring unit. That is, the MP constantly monitors (measures) the voltage of the lead battery 10 and determines the engine state of engine start, engine start, and engine stop from the change in voltage measured via the voltage measurement unit.

<Engine start>
MP is a voltage drop of Y (0.50 to 3.0) V or more within X (1 to 100) ms after the start of discharge of the lead battery 10 (for example, preferably a voltage of 1.5 V or more within 15 ms). It is determined whether or not the engine has started and the engine has been started when the determination is affirmative. As the voltage value of a, for example, a voltage value of 109 to 121% of the OCV of the lead battery 10 can be used. On the other hand, when a negative determination is made, it is considered that an in-vehicle electrical component such as a car air conditioner or a car navigation system has been started, and the engine is not started.

<Engine is running>
MP is a lead battery because the voltage of the lead battery 10 is always greater than or equal to the predetermined value a described above after the affirmative determination of the engine start described above (the generator (alternator, regulator) is operating when the engine is running). 10 is in a charged state, and the voltage is higher than OCV.) When the determination is affirmative, it is determined that the engine is being started.

<Engine stop>
(1) After determining that the engine is being started, if the voltage of the lead battery 10 becomes equal to or less than a certain value b: it is determined that the engine is stopped from the engine starting state. For example, a voltage value of 103 to 108% of the OCV of the lead battery 10 can be used as the voltage value of b. Also, (2) after determining that the engine is being started, when the voltage of the lead battery 10 decreases at a speed equal to or higher than a certain value c and the voltage drop is equal to or more than a certain value d: It is determined that the vehicle has stopped. The voltage drop rate of c can be 1.0 to 4.0 V / s, and the voltage drop width of d can be 0.05 to 0.20 V. Further, (3) after determining that the engine is in operation, the voltage of the lead battery 10 decreases to a certain value e or less, and the voltage change width at that time is a certain constant value f with a certain time width. When the value is less than or equal to g: It is determined that the engine is stopped from the engine starting state. A voltage value of 102 to 109% of the OCV of the lead battery 10 can be used as the voltage value of e, 0.01 to 1.0 s can be used as the value of f, and 0.1 to 0.3 V can be used as the change width of the voltage of g. . MP determines that the engine has stopped when it falls under any of (1) to (3).

  In addition, MP acquires the voltage of the lead battery 10 measured after the polarization reaction of the lead battery 10 is eliminated after the engine is stopped (for example, after 6 hours have elapsed) as an OCV.

(Operation)
Next, with reference to a flowchart, the operation of the AI unit 1 will be described with the MP as a main component. When power is supplied from the lead battery 1 to the AI unit 1, program data including a program and a determination threshold value Vth is expanded from the ROM to the RAM in the initial setting process to determine deterioration of the lead battery 10. The deterioration determination routine is executed.

  As shown in FIG. 2, in the deterioration determination routine, first, in step 102, the process waits until the engine is started. The MP determines the engine start based on the engine state determination described above. When it is determined that the engine has been started, in the next step 104, referring to the voltage value stored in the RAM, the first lowest voltage value measured at the start of discharge of the lead battery 10 and after the start of discharge of the lead battery 10 The lowest voltage value measured within 15 ms is calculated as the lowest voltage value Vst at engine start. Note that the MP measures the temperature of the lead battery 10 via the temperature measuring unit, and corrects the temperature of the lowest voltage value Vst to, for example, a voltage value at room temperature (25 ° C.) based on the acquired temperature value.

  In the next step 106, it is determined with reference to the EEPROM whether or not the lowest voltage value Vst0 at the time of starting the engine of the lead battery 10 in the non-deteriorated state has already been acquired. That is, for example, if the value of the lowest voltage value Vst0 is written at a predetermined address of the EEPROM or if a flag is set, it is determined that the lowest voltage value Vst0 has already been acquired (affirmed), and a null or flag is set. If not, it is determined that the minimum voltage value Vst0 has not been acquired (No).

  When the determination in step 106 is negative, in step 108, a Vst0 acquisition subroutine for acquiring the lowest voltage value Vst0 at the time of engine start with the lead battery 10 in the non-degraded state is executed. In the present embodiment, in this Vst0 acquisition subroutine, the minimum voltage value Vst * at the time of starting the engine in the non-degraded state of the lead battery 10 that satisfies a predetermined condition among the minimum voltage values Vst at the time of starting the engine of the lead battery 10 is 5 Are obtained, and the average value thereof is calculated as the above-described minimum voltage value Vst0 and stored in the EEPROM. As this predetermined condition, for example, (1) it is within half a year from when the lead battery 10 is attached to the automobile, and (2) the OCV of the lead battery 10 before starting the engine (for example, after the previous engine stop) The open circuit voltage when 6 hours have passed) can be 12.5 V or higher (hereinafter, this condition (2) is referred to as an acquisition condition). As is clear from condition (1), “no deterioration state” of “minimum voltage value Vst0 at the time of engine start in the non-deterioration state of lead battery 10” in this embodiment is a complete state in which SOH is 100%. Not only the non-degraded state but also the substantially non-degraded state in the initial state in which the lead battery 10 is healthy.

  As shown in FIG. 3, in the Vst0 acquisition subroutine, first, in step 204, it is determined whether or not it is less than half a year after the lead battery 10 is attached to the automobile. In the present embodiment, since the operation button 3 is arranged on the operation display unit 2, in order to determine the condition (1), for example, when the operation button 3 is pressed a predetermined number of times by a predetermined operation, the MP is Alternatively, it may be determined that the lead battery 10 is attached to the automobile and time is measured from that time. When a negative determination is made in step 204, it is considered that the lead battery 10 is not in a non-degraded state, and the Vst0 acquisition subroutine is terminated.

  On the other hand, if the determination in step 204 is affirmative, it is determined in step 206 whether or not the acquisition condition (condition (2) described above) is satisfied.

  If the determination in step 206 is negative, it is determined in step 208 whether or not the minimum voltage value Vst * written in the EEPROM is zero. As described above, a total of five minimum voltage values Vst * are finally written in the EEPROM. For example, when the engine is started for the first time after the lead battery 10 is mounted on an automobile, the minimum voltage value Vst * is Not written to EEPROM. If the determination in step 208 is affirmative, the minimum voltage value Vst calculated in step 104 of FIG. 2 does not satisfy the acquisition condition in step 206, but the minimum voltage value at the time of engine start of the non-degraded lead battery 10 is started. It is stored in the EEPROM as a temporary value of Vst *. The reason for this will be described later. On the other hand, when a negative determination is made in step 208, the minimum voltage value Vst calculated in step 104 is used as data for acquiring the minimum voltage value Vst * at the time of engine start of the non-degraded lead battery 10. Without completing the Vst0 acquisition subroutine.

  On the other hand, if the determination in step 206 is affirmative, in the next step 214, it is determined whether or not the minimum voltage value Vst * written in the EEPROM is zero. When an affirmative determination is made in step 214, the lowest voltage value Vst calculated in step 104 in FIG. 2 is written in the EEPROM as the lowest voltage value Vst * at the time of engine start of the non-degraded lead battery 10, and the Vst0 acquisition subroutine is executed. finish. On the other hand, when the determination in step 214 is negative, it is determined in step 218 whether or not one minimum voltage value Vst * at the time of starting the engine of the non-degraded lead battery 10 is written in the EEPROM. If the determination in step 218 is affirmative, in the next step 220, refer to the EEPROM whether or not data replacement (data replacement with the temporary value when stored in the EEPROM as a temporary value in step 210) is necessary. If the determination in step 220 is affirmative, the provisional value written in the EEPROM in step 210 is the minimum voltage value Vst * at the time of engine start in the non-degraded state of the lead battery 10 (in step 104 of FIG. 2). The calculated minimum voltage value Vst is rewritten to the minimum voltage value satisfying the above-mentioned predetermined condition), and the Vst0 acquisition subroutine is rewritten. To the end.

  If a negative determination is made in step 220, in step 224, the lowest voltage value Vst * at the time of engine start of the second non-degraded lead battery 10 is written in the EEPROM, and the lowest voltage already written in the next step 228 is written. The average value of the values Vst * is calculated, the calculation result is also stored in the EEPROM, and the Vst0 acquisition subroutine is terminated. If the determination in step 218 is negative, in step 226, the minimum voltage value Vst * at the time of engine start of the lead battery 10 in the non-degraded state is written in the EEPROM, and the process proceeds to step 228. The lowest voltage value Vst * at the time of starting the engine in the non-degraded state of the five lead batteries 10 is written in the EEPROM (step 226), and the lowest voltage value Vst0 of the average value of the five lowest voltage values Vst * is calculated. 2 (step 228), the determination at step 106 in FIG. 2 is always affirmative, and thereafter the Vst0 acquisition subroutine is not executed.

  If the determination in step 106 of FIG. 2 is affirmative, the minimum voltage value Vst0 at the time of engine start of the non-degraded lead battery 10 is read from the EEPROM in step 112, and the voltage difference ΔVst (= Vst0− Vst) is calculated.

  Next, in step 116, it is determined whether or not the voltage difference ΔVst is larger than the determination threshold value Vth. When the determination is negative, since the deterioration has not progressed to the extent that the lead battery 10 needs to be replaced, it is not necessary to issue a warning to the user (driver), and the process returns to step 102.

  On the other hand, when the determination in step 116 is affirmative, in the next step 118, the process waits until the engine stops. The MP determines the engine stop by the above-described engine state determination. When it is determined that the engine is stopped, in the next step 120, as described below, the fact that the lead battery 10 needs to be replaced is notified by an audible means using a buzzer and a visual means using an LED, and the process returns to step 102. .

  In the present embodiment, since the AI unit 1 is accommodated in the upper lid 9 of the lead battery 10, the AI unit 1 is disposed at a place where the lead battery 10 is installed. Many are in the engine room or in an automobile such as a passenger compartment, and the alarm sound emitted by the buzzer is difficult to hear due to vehicle noise while driving. For this reason, the generation timing of the alarm sound generated by the AI unit 1 is set as follows, and the alarm sound is generated at a timing at which the user can easily hear the alarm sound, so that the alarm sound is reliably transmitted to the user. The AI unit 1 outputs a high level signal to the gate of the transistor that turns on the LED via the DA converter immediately after determining that the engine has stopped, and turns on the LED. A high-level signal is sent to the gate of the transistor that operates the buzzer via the DA converter of this type to generate a warning sound.

  At the timing of stopping the engine from the engine starting state, it is estimated that the user often performs a series of operations of getting out of the automobile, closing the door, locking the door, and leaving the automobile. Accordingly, when a warning sound is generated, if a certain time lag is provided from the timing when it is determined that the engine has stopped, there is a high possibility that an alarm will be transmitted to the user. In addition to the notification start timing, the notification continuation time by the buzzer warning sound is also an important factor of notification.

  As these specific times and times, it is preferable that the notification start by the buzzer is performed between 0 and 60 seconds after the engine is stopped. The notification duration is preferably 2 seconds or more, and it is preferable to continue notification for a maximum of several minutes. Moreover, since the optimal value of these time and time changes with the usage forms of a vehicle, what is necessary is just to be determined by each case according to the use of the lead battery 10. FIG. In addition, the lead battery 10 of this embodiment is a thing for general passenger cars, The alerting | reporting continuation time of the warning sound by a buzzer is set to about 30 seconds.

  According to the AI unit 1 of the present embodiment, in most cases, the alarm sound can be reliably transmitted to the user, but it is actually determined that the alarm sound is generated on the assumption that several missed hearings occur. The value Vth is preferably set slightly higher with a margin.

  On the other hand, in the display of the battery state of the lead battery 10 by the LED, the LED is turned on and displayed immediately after the engine is stopped. The time is about 5 minutes in this embodiment. Further, the AI unit 1 has an operation button 3 disposed on the operation display unit 2. This is because a user who hears a warning sound from the buzzer or desires to know the battery state can check the health state of the lead battery 10. That is, when there is an input by the operation button 3, the battery state is displayed by the LED so that the user can arbitrarily grasp the battery state. In the present embodiment, the LED indicating that the lead battery 10 needs to be replaced is lit using a red LED in order to alert the user.

(Action etc.)
Next, the operation and the like of the lead battery 10 of the present embodiment will be described focusing on the AI unit 1.

  The AI unit 1 measures the voltage of the lead battery 10 via the voltage measurement unit, and calculates the minimum voltage value Vst from the voltage measured at the time of engine start by the calculation unit (MP) (step 104). At this time, a voltage drop (preferably within 15 ms) of a predetermined voltage Y (Y: 0.5 to 3.0 V) or more within a predetermined time X (X: 1 to 100 ms) from the measured voltage of the lead battery 10. When a positive determination is made, it is determined whether or not the voltage value is equal to or higher than a predetermined value a (a: 109% of the open circuit voltage of the lead battery 10) thereafter. The minimum voltage value Vst is calculated, and the negative voltage value Vst is not calculated considering that the lead battery 10 is discharged to the on-vehicle electrical component when negative determination is made (step 102). Whether the voltage difference ΔVst between the lowest voltage value Vst0 when starting the engine and the lowest voltage value Vst of the lead battery 10 measured most recently when the lead battery 10 stored in the EEPROM is in the non-degraded state is larger than the determination threshold value Vth. (Step 116), when it is determined that it is large, the user is informed that the lead battery 10 has to be replaced after the engine is stopped (step 120).

  In order for the AI unit 1 to determine the health state of the lead battery 10, in order to calculate the voltage difference ΔVst (step 114), the minimum voltage value Vst * in the non-degraded state of the lead battery 10 that satisfies the above-described predetermined condition is determined. However, if the minimum voltage value Vst does not satisfy the predetermined condition, the minimum voltage value Vst * is not acquired and the health condition of the lead battery 10 cannot be determined. As a cause of this, for example, when the lead-acid battery 10 has a long over-the-counter inventory period and the lead-acid battery 10 seems to be discharged, and the driver does not drive the automobile much after the lead-acid battery 10 is attached to the automobile, the engine of the lead-acid battery 10 Since the open circuit voltage before the start is low (condition (2) is not satisfied), the minimum voltage value Vst * is not acquired. If even one minimum voltage value Vst * can be acquired, this is the minimum voltage value Vst0. Can be used to calculate the voltage difference ΔVst. Therefore, in the present embodiment, even when the MP determines that the minimum voltage value Vst at the time of the first engine start of the lead battery 10 does not satisfy the predetermined condition, the minimum value at the time of the engine start in the non-degraded state of the lead battery 10. The provisional value of the voltage value Vst0 is stored in the EEPROM (step 210), and the voltage difference ΔVst is calculated using the provisional value to determine the health condition of the lead battery 10.

  According to the AI unit 1 of the present embodiment, the health state of the lead battery 10 is determined from the lowest voltage value Vst0 at the time of engine start and the latest lowest voltage value Vst calculated in the non-deteriorated state of the lead battery 10. Even if it is possible to determine the health condition of the lead battery 10 without using a current sensor and the minimum voltage value Vst at the time of the first engine start of the lead battery 10 is determined not to satisfy the predetermined condition, the lead battery Since it is stored in the EEPROM as a temporary value of the minimum voltage value Vst * at the time of starting the engine in the 10 non-deteriorated state, the health state of the lead battery 10 can always be determined regardless of the state of the lead battery 10.

  Further, the AI unit 1 of the present embodiment includes a nonvolatile EEPROM, and the lowest voltage value Vst * that can be obtained only in the non-degraded state of the lead battery 10 is written in the EEPROM (step 110), and is used for determining deterioration. (Step 112). Therefore, for example, the AI unit 1 can be re-supplied even after the automobile on which the lead battery 10 is mounted is not moved for a long time (the lead battery 10 is not charged) and the power supply to the AI unit 1 is interrupted. In this case, the deterioration state of the lead battery 10 can be determined without losing the data of the minimum voltage value Vst * that can be acquired only in the non-deterioration state. Further, when storing the minimum voltage value Vst * at the time of starting the engine in the non-degraded state of the lead battery 10, in order to replace the temporary value of the minimum voltage value Vst * (step 222), the storage capacity of the EEPROM can be reduced, Cost can be reduced.

  In addition, since the AI unit 1 of the present embodiment sets the average value of the five lowest voltage values Vst * to the lowest voltage value Vst0, it is possible to prevent variations in the lowest voltage value Vst * and lead by the AI unit 1 The determination accuracy of the health state of the battery 10 can be increased.

  In the present embodiment, for the sake of simplicity of explanation, an example in which the health state of the lead battery 10 is determined at two levels, that is, good and requires replacement using the determination threshold value Vth is shown. The present invention is not limited to this, and a plurality of determination threshold values may be set, and for example, determination may be performed in three levels of good, attention required, and replacement required, or more.

  Further, in the present embodiment, the example in which the deterioration determination of the lead battery 10 is performed by comparing the voltage difference ΔVst between the minimum voltage value Vst0 and the minimum voltage value Vst with the determination threshold value Vth is shown. For example, the ratio between the minimum voltage value Vst0 and the minimum voltage value Vst may be compared with a determination threshold value.

  Further, in the present embodiment, when the minimum voltage value Vst * is not written in the EEPROM, even if the acquisition condition is not satisfied, only one minimum voltage value Vst at the time of starting the engine of the lead battery 10 is assumed temporarily. Although an example of storing is shown (step 210), the present invention is not limited to this, and in order to prevent variation of this temporary value, for example, the minimum voltage value at the start of the engine several times from the beginning of the lead battery 10 is used. Vst may be temporarily stored, and the average value thereof may be used as a temporary value of the minimum voltage value Vst *.

  In the present embodiment, an example in which the average value of the five lowest voltage values Vst * is set to the lowest voltage value Vst0 is shown, but the present invention is not limited to this. For example, a plurality of lowest voltage values Vst * The mode value or the median value of may be the minimum voltage value Vst0.

  Furthermore, in this embodiment, although the lead battery 10 is in an undegraded state, in particular, as an example of determining the condition (1) described above, the operation button 3 is pressed a predetermined number of times by a predetermined operation. The MP may monitor whether or not the engine has been started for the first time, and when an affirmative determination is made, the lead battery 10 may be regarded as being attached to the automobile. In this aspect, the starting point setting by the operation button 3 can be eliminated.

  In the present embodiment, the example in which the AI unit 1 as the battery state determination device is accommodated in the upper lid 9 of the lead battery 10 is shown, but the AI unit 1 may be used independently from the lead battery 10.

  The present invention provides a battery state determination device that can accurately determine the health state of a lead battery without using a current sensor, and an automotive lead battery equipped with the battery state determination device. Since it contributes to the manufacture and sale of lead batteries for automobiles, it has industrial applicability.

1 is an external perspective view of a lead battery according to an embodiment to which the present invention is applicable. It is a flowchart of the deterioration determination routine which the microprocessor of the AI unit accommodated in the lead battery of the embodiment executes. 3 is a flowchart of a Vst0 acquisition subroutine executed by the microprocessor of the AI unit and showing details of step 108 in FIG. It is a graph which shows typically the voltage between terminals of a lead battery at the time of engine starting. It is a graph which shows the measured value when the voltage between terminals of the lead battery at the time of engine starting is measured for every predetermined time in time series. It is a graph which shows the minimum voltage value at the time of engine starting of the lead battery of an undeteriorated state, and the minimum voltage value at the time of engine start of the lead battery after deterioration.

Explanation of symbols

1 AI unit (voltage measurement means, Vst calculation means, Vst0 storage means, state determination means, battery state determination device)
10 Lead battery

Claims (6)

In a battery state determination device for determining the health state of an automotive lead battery,
Voltage measuring means for measuring the voltage of the lead battery;
Vst calculating means for calculating a minimum voltage value Vst at the time of engine start of the lead battery from the voltage measured by the voltage measuring means;
It is determined whether or not the minimum voltage value Vst calculated by the Vst calculation means satisfies a predetermined condition, and when it is determined that the minimum voltage value Vst is satisfied, the minimum voltage value Vst Vst0 storage means for storing the voltage value Vst0 in the memory;
Based on the lowest voltage value Vst0 stored in the memory by the Vst0 storage means and the latest lowest voltage value Vst calculated by the Vst calculation means in the non-degraded or deteriorated state of the lead battery, the health state of the lead battery is determined. State determination means for determining;
The Vst0 storage means includes the memory as a provisional value of the minimum voltage value Vst0 even when it is determined that at least the minimum voltage value Vst at the time of starting the first engine of the lead battery does not satisfy the predetermined condition. The battery state determination device characterized by being stored in the battery.   The memory is a non-volatile memory, and the Vst0 storage means determines whether the temporary value is stored when storing the minimum voltage value Vst0 in the memory. The battery state determination device according to claim 1, wherein the value is replaced with the minimum voltage value Vst0.   The said predetermined condition is less than a predetermined period after the said lead battery was attached to the motor vehicle, and the open circuit voltage before the engine start of the said lead battery is more than a predetermined voltage value, The said specific condition is characterized by the above-mentioned. Battery state determination device.   The Vst0 storage means stores a plurality of the minimum voltage values Vst0 in the memory, and the state determination means selects any one of an average value, a mode value, and a median value of the plurality of minimum voltage values Vst0 stored in the memory. The battery state determination device according to claim 1, wherein the health state of the lead battery is determined using a determination threshold value from the latest minimum voltage value Vst.   The Vst calculation means is a voltage drop of a predetermined voltage Y (Y: 0.5 to 3.0 V) or more within a predetermined time X (X: 1 to 100 ms) from the voltage of the lead battery measured by the voltage measuring means. It is then determined whether or not the voltage value is equal to or higher than a predetermined value a (a: 109% of the open circuit voltage of the lead battery), and the minimum voltage value Vst is calculated when an affirmative determination is made. The battery state determination device according to claim 1, wherein the minimum voltage value Vst is not calculated when a negative determination is made.   An automotive lead battery comprising the battery state determination device according to any one of claims 1 to 5.

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