JP5321184B2 - Battery diagnostic device and battery - Google Patents

Description

  The present invention relates to a battery diagnostic device and a battery, and more particularly to a battery diagnostic device for diagnosing a battery state of a battery mounted on a vehicle and a battery including the device.

  Battery performance monitoring and battery status control have become increasingly important in recent years as the load on the batteries used in automobiles (vehicles), portable devices, and the like has increased with the increase in performance. . In the case of automobile batteries, based on idle stop start (ISS) and regenerative charging that are performed to reduce exhaust gas, the battery state is accurately detected in order to keep the battery state suitable for these applications. Technology is desired. Lead batteries are typical batteries that can be applied to these applications.

  In general, the positive terminal of a battery mounted on the vehicle is connected to the center terminal of the ignition switch. The ignition switch 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 terminals can be switched and connected in a rotary manner. The START terminal is connected to an engine starting cell motor (starter), and the starter can transmit a rotational driving force to the rotation shaft of the engine via a clutch mechanism. The ON / ACC terminal is connected to a generator (alternator) that generates electric power by rotating the engine via vehicle-side equipment such as an air conditioner, a radio, a lamp, and a regulator. On the other hand, the negative external output terminal of the battery is connected to the other end of the vehicle side device, the starter and the regulator as a ground potential.

  The battery state of such a vehicle-mounted battery is diagnosed by a battery diagnostic device. In the battery diagnosis device, a technique is known in which a voltage after a predetermined time has elapsed after starting energization at the time of starting the engine and a battery state is detected by comparison with a threshold value (for example, see Patent Document 1). In this battery diagnostic apparatus, the threshold value is set by a function of the intake air temperature, and the atmosphere state in which the battery is arranged is taken into consideration. In addition, a technique for actually measuring the engine starting voltage (minimum voltage) of a new battery and calculating a threshold value is also known (see, for example, Patent Document 2). In this battery diagnostic apparatus, a temperature-corrected value is used for the engine starting voltage in a new battery used for calculation of the threshold value.

Japanese Patent No. 3673895 (Claim 1, paragraph "0018", paragraph "0020" and FIG. 3) JP 2007-238001 A (Claims 3, 5, 7 to 9, paragraph “0018”, paragraphs “0012” to “0020” and FIG. 5)

  For example, at a low temperature such as below freezing point, the measurement variation of the engine starting voltage at the time of starting the engine is large, which becomes a large error factor in diagnosis of the battery state. In particular, if the engine starting voltage (minimum voltage) at the time of starting the engine at a low temperature is recorded as the engine starting voltage of a new battery and treated as a diagnostic criterion, the engine starting voltage in the new state will be used for subsequent battery deterioration judgment (diagnosis) It will affect everything.

  An object of the present invention is to provide a battery diagnosis device with high diagnostic accuracy and a battery including the device.

  In order to solve the above-described problem, a first aspect of the present invention provides a battery diagnosis apparatus for diagnosing a battery state of a battery mounted on a vehicle, a nonvolatile memory for storing battery data, and the battery A voltage measuring means for measuring the voltage of the battery, a temperature measuring means for measuring the temperature of the battery, and detecting whether the voltage measured by the voltage measuring means has a voltage drop equal to or greater than a predetermined voltage value. Measured by the engine start detection means for detecting, the minimum voltage acquisition means for acquiring the minimum voltage value Vst at the time of engine start in the new state of the battery from the voltage measured by the voltage measurement means, and the temperature measurement means Temperature acquisition means for acquiring the temperature of the battery at the time of starting the engine or before and after it from the temperature, and the minimum voltage value Vst acquired by the minimum voltage acquisition means and the temperature acquisition Recording means for recording the temperature obtained by the means in the non-volatile memory, and after the recording means records the minimum voltage value Vst and temperature in the non-volatile memory, engine start is detected by the engine start detecting means. Or after that, it is determined whether the engine is started at a temperature higher than the temperature recorded in the non-volatile memory, and when the determination is affirmative, the minimum voltage value acquired by the minimum voltage acquisition means Vst and overwriting control means for controlling the recording means to overwrite the nonvolatile memory with the high temperature acquired by the temperature acquisition means.

  In this aspect, a plurality of sets of minimum voltage values Vst and temperatures are recorded in the non-volatile memory by the recording means, and the overwriting control means is non-volatile when the engine start is detected by the engine start detecting means or after that. It is determined whether any temperature recorded in the memory is lower than a predetermined temperature, and whether the engine is started at a temperature higher than the temperature recorded in the nonvolatile memory. When the determination is affirmative, the recording unit may be controlled to overwrite the nonvolatile memory with the lowest voltage value Vst acquired by the lowest voltage acquisition unit and the high temperature acquired by the temperature acquisition unit. At this time, the overwriting control means records the recording means so as to overwrite the set of the lowest voltage value Vst and temperature corresponding to the lowest temperature among the plurality of sets of lowest voltage value Vst and temperature recorded in the nonvolatile memory. Is preferably controlled.

  Further, in this aspect, the circuit further includes an open circuit voltage detecting means for detecting the open circuit voltage OCV of the battery, and the recording means includes the non-volatile memory and the OCV before the engine start detected by the open circuit voltage detecting means. Recording or detecting the open circuit voltage detection means for detecting the open circuit voltage OCV of the battery and the lowest voltage value Vst acquired by the lowest voltage acquisition means before the engine start detected by the open circuit voltage detection means Vst-OCV correction means for OCV correction to a value at the reference OCV using OCV is further provided, and the recording means records the minimum voltage value Vst corrected by the Vst-OCV correction means in the nonvolatile memory. It may be. Further, the recording device includes a Vst-temperature correction unit that corrects the minimum voltage value Vst acquired by the minimum voltage acquisition unit to a value at a reference temperature using the temperature acquired by the temperature acquisition unit. The minimum voltage value Vst corrected by the Vst-temperature correction means may be recorded in the nonvolatile memory. Then, when the engine start is detected by the engine start detecting means, or after that, the latest battery voltage measured by the voltage measuring means is compared with the lowest voltage value Vst recorded in the nonvolatile memory by the recording means. Battery state diagnosis means for diagnosing the battery state of the battery by reading, and the battery state diagnosis means reads the lowest voltage value Vst from the nonvolatile memory at least at the time of power supply restart and battery state diagnosis. You may do it. Furthermore, in this aspect, at least one of current measurement means for measuring the current flowing through the battery and information acquisition means for acquiring position information of the ignition switch of the vehicle is provided, and the engine start detection means is measured by the voltage measurement means. The ignition switch position information obtained by detecting whether there was a voltage drop greater than a predetermined voltage value in the measured voltage and whether the current measured by the current measuring means had a current increase greater than the predetermined current value, or obtained by the information obtaining means Thus, the engine start may be detected.

  Moreover, in order to solve the said subject, the 2nd aspect of this invention is a battery provided with the battery diagnostic apparatus of the 1st aspect.

  According to the present invention, when the engine start is detected by the engine start detecting means after the recording means records the minimum voltage value Vst and the temperature in the nonvolatile memory by the overwriting control means, or after that, the nonvolatile memory It is determined whether or not the engine has started at a temperature higher than the temperature recorded in the above. When the determination is affirmative, the minimum voltage value Vst acquired by the minimum voltage acquisition unit and the high temperature acquired by the temperature acquisition unit are non-volatile. Since the recording means is controlled to overwrite the volatile memory, the lowest voltage value Vst at the time of engine start at a low temperature is excluded from the standard of the battery state diagnosis as the lowest voltage value Vst of the new battery, so that the diagnosis accuracy is high. The effect that a battery diagnostic apparatus can be provided can be obtained.

It is a top view of a lead battery with a battery diagnostic device of an embodiment which can apply the present invention. It is an external appearance perspective view of the battery diagnostic apparatus of the lead battery of an embodiment. It is a characteristic diagram which shows typically the voltage waveform between the external terminals of the lead battery at the time of engine starting. It is a flowchart which shows the Vst0 decision processing routine which CPU of the battery diagnostic apparatus of the lead battery of embodiment performs. It is a graph which shows the temperature correction amount of the minimum voltage value Vst at the time of engine starting. It is a flowchart which shows the Vst0 confirmation process routine which CPU of the battery diagnostic apparatus of the lead battery of a comparative example performs.

  Embodiments in which the present invention is applied to a lead battery with a battery diagnostic device will be described below with reference to the drawings.

(Constitution)
As shown in FIG. 1, the lead battery 20 of the present embodiment is a 14V system (nominal voltage: 12V) in-vehicle battery (for example, 55B24 type), and has an external terminal on one side along the longitudinal direction of the upper surface of the lead battery 20. 11 stands upright apart. A recess is formed in the upper lid of the lead battery 20, and a battery diagnostic device 10 that operates using the lead battery 20 as a power source is incorporated in this recess and screwed with a screw (not shown).

  As shown in FIG. 2, the battery diagnostic device 10 has a substantially plate shape, and four LEDs 1 for displaying a battery state (in this example, a charged state SOC and a deteriorated state SOH), and a user Push switch 2, buzzer sound release hole 3 and two for notifying the battery diagnosis device 10 that the battery state of the battery (for example, when the SOH of the lead battery 20 is in a state of caution) is recognized Except for the bus bar 4, the resin is molded and accommodated in the casing 6. The bus bar 4 is produced by punching a phosphor bronze plate for 0.2 mm spring. Both ends of the bus bar 4 are ring-shaped and a plurality of slits are formed concentrically on the inside, and a structure that fits to the external terminal 11 of the lead battery 20 is adopted. In the vicinity of the bus bar 4 led out from the casing 6, an expansion / contraction absorption bending portion 5 is formed.

  The battery diagnosis apparatus 10 includes a measurement unit, a calculation unit, a power supply unit, a storage unit, a sound emission unit, a display unit, and an input unit. The measurement unit includes a voltage measurement unit having a differential amplifier that drops the battery voltage to a voltage that can be measured by the A / D converter, and a temperature measurement unit that detects the temperature of the battery with a temperature sensor such as a thermistor. Yes. The temperature sensor is inserted into a long hole formed in a substantially central portion of the upper lid and fixed with an adhesive. The above-described bus bars 4 are respectively connected to the input side of the differential amplifier circuit in the casing 6. The arithmetic unit can be constituted by, for example, an A / D converter, a D / A converter, a CPU, a ROM, a RAM, and a one-chip microcomputer with a built-in watchdog timer (WDT). Note that an oscillation circuit is connected to the microcomputer for accurate time measurement.

  A power supply unit, a storage unit, a sound emitting unit, a display unit, and an input unit are connected to the calculation unit via an external bus. The power supply unit includes, for example, a shunt regulator IC, a reference power supply IC that generates a reference power supply for the A / D converter, and the like. The storage unit includes a rewritable (overwritten) nonvolatile memory such as an EEPROM. The sound emitting unit is composed of a buzzer, a transistor for driving the buzzer, and a plurality of resistors for stably operating the transistor. The buzzer sound emitting hole 3 described above is formed immediately above the buzzer. The display unit includes the four LEDs 1 described above, a transistor for turning on or blinking the LED, and a plurality of resistors for stably operating the transistor. The input unit includes a transistor that outputs a signal when the push switch 2 is pressed, and a plurality of resistors and capacitors for stably operating the transistor.

(Operation)
FIG. 3 is a characteristic diagram schematically showing a voltage waveform between the external terminals of the lead battery when the engine is started. As shown in FIG. 3, when the engine is started, a large current flows from the lead battery 20 to the above-described starter via the ignition switch, so that the voltage between the external terminals of the lead battery 20 sharply decreases. The voltage between the external terminals of the lead battery 20 rises while pulsating after taking the minimum voltage value Vst. The battery diagnosis device 10 diagnoses the battery state (deterioration state) of the lead battery 20 using the lowest voltage value Vst at the time of engine start.

<Vst0 determination processing routine>
FIG. 4 is a flowchart showing a Vst0 determination processing routine executed by a CPU (hereinafter abbreviated as CPU) of the calculation unit of the battery diagnosis apparatus 10. In this Vst0 determination processing routine, when power is supplied from the lead battery 20 to the battery diagnostic device 10, whether a predetermined address (for example, memory address 1 described later) of the nonvolatile memory (storage unit) is in a null state without writing It is determined whether or not (or whether or not specific information is written in advance in a specific address and the information of the specific address matches the predetermined information), and is executed when an affirmative determination is made. In other words, the minimum voltage value Vst at the time of starting the engine is 25 ° C. when the lead battery 20 is in a new state (not necessarily SOH = 100%, and may be substantially new). This means a representative value taken under the condition of full charge, which will be described later in detail.

  In the Vst0 determination processing routine, first, in step 102, the value of the counter N_Vst is set to 0, and in the next step 104, the open circuit voltage OCV when 6 hours or more have elapsed after the engine is stopped is acquired. In the present embodiment, the acquired open circuit voltage OCV is stored in a predetermined address of the RAM (rewritten every predetermined period), and the OCV before starting the engine is adopted as the OCV in a stable state of the lead battery 20.

  That is, as shown in FIG. 3, during engine operation, a voltage of, for example, 13.5 V or more is supplied between the external terminals of the lead battery 20 via the alternator and regulator described above, and an overcharged state is not achieved. In principle, the lead battery 20 is charged in principle. When the engine is stopped, the voltage between the external terminals of the lead battery 20 becomes less than 13.5V. However, when the lead battery 20 is new and almost fully charged, for example, the voltage becomes 12.5V or more, and the ignition When the is in the OFF position, since a current does not flow from the lead battery 20 to the vehicle side device (or only a dark current flows), a slight voltage increase (for example, 0.1 V / min) is observed. For example, the CPU records the voltage fluctuation in the RAM every 40 msec and detects this voltage rise, thereby grasping that the ignition switch is located at the OFF terminal. In this state, current does not flow from the lead battery 20 to the vehicle-side device, but the polarization state of the lead battery 20 has not been eliminated (is not the OCV of the lead battery in a stable state), so the watch dog timer is activated. Then, it is determined whether or not a predetermined time (for example, 6 hours) has elapsed from the time when it is determined that the vehicle is positioned at the ignition OFF position. When the engine is started within this predetermined time, it is determined again whether the predetermined time has elapsed from the time when it was determined that the engine was positioned at the ignition OFF position. The voltage is stored in the RAM as an OCV (in a stable state of the lead battery 20) in which the polarization state of the lead battery 20 is eliminated.

  In step 104, engine start is detected. When the ignition switch is positioned from the OFF terminal to the ON / ACC terminal, dark current flows through the vehicle-side device, so the voltage between the external terminals of the lead battery 20 is about 0. 0 from the stable voltage state (see the left side in FIG. 3). A voltage drop of about 1 V / min occurs. Until this time, as described above, the CPU records the voltage fluctuation in the RAM every 40 msec, for example, but when this voltage drop is detected, the recording cycle to the RAM is changed to, for example, 1 msec to change the voltage. Record changes in RAM. Then, the latest voltage value taken in via the voltage measuring unit and the A / D converter is compared with the voltage value stored in the RAM (for example, the oldest voltage value), for example, a voltage difference of 1.5 V or more The engine start is detected by determining whether or not there is. Note that the CPU maintains the recording cycle in the RAM at the above-described 1 msec for a predetermined time (for example, 12 msec) after detecting the engine start, and changes the recording cycle again to the above-described 40 msec after the predetermined period has elapsed.

  In step 106, the lowest voltage value Vst is detected by searching for the smallest value among the voltage values recorded in the RAM every 1 msec (see also FIG. 1). Moreover, the temperature of the lead battery 20 at the time of engine starting is taken in via a temperature measurement part and an A / D converter. Strictly speaking, it is ideal to capture the temperature at the lowest voltage value Vst. However, since the temperature of the lead battery 20 does not change rapidly, in this example, the temperature after measuring the lowest voltage value Vst. However, the temperature may be taken in at step 104 (when the ignition switch is positioned from the OFF terminal to the ON / ACC terminal or when engine start is detected). Further, in step 106, the value of the counter N_Vst is incremented by 1.

  Next, at step 108, it is determined whether the value of the counter N_Vst is 5 or more. That is, the above-described nonvolatile memory has five addresses (memory addresses 1 to 5 described later) for storing the minimum voltage value, and in step 108, all the five addresses of the nonvolatile memory are filled. It is judged whether or not it was done.

If the determination in step 108 is negative, in step 110, the minimum voltage value Vst detected in step 106 is temperature-corrected with the temperature of the lead battery 20 taken in step 106, and stored in the RAM in step 104. The minimum voltage value Vst ^* converted to the value at the standard temperature and the standard OCV is calculated with the OCV corrected in advance, and in the next step 112, the minimum voltage value Vst ^* calculated in step 110 is calculated in step 106. Then, the temperature is recorded in the nonvolatile memory together with the temperature (at the time of Vst measurement) taken in step, and the process returns to step 104.

  FIG. 5 is a graph showing the temperature correction amount of the minimum voltage value Vst at the time of engine start in the 55B24 battery. The temperature correction amount increases as the temperature decreases. On the contrary, since the characteristic change is small on the high temperature side of 25 ° C. or higher, the correction value is treated as 0. By adding the correction values in FIG. 5, the minimum voltage value Vst can be corrected to a reference temperature of 25 ° C. For example, if it is -10 degreeC, if about 0.55V is added to an actual measurement value, it will be 25 degreeC conversion.

  The OCV correction can be calculated by regarding the OCV acquired in step 104, that is, the stable voltage when the lead battery 20 is left for 6 hours or more as the OCV, and substituting into the following equation 1, for example. In Equation 1, OCV0 is a reference full-charge voltage, and in this example, it is 12.76V.

As described above, the nonvolatile memory has five addresses, and each time the lowest voltage value Vst ^* is calculated, one set of data of the temperature at the time of Vst measurement and the lowest voltage value Vst ^* is recorded. Finally, 5 sets of data are recorded. Therefore, the counter N_Vst represents the count value of the number of times of calculation of the minimum voltage value Vst ^* or the number of times of recording in the nonvolatile memory.

On the other hand, when the determination in step 108 in FIG. 4 is affirmative, in step 114, the five lowest voltage values Vst ^* recorded in the nonvolatile memory are read and their average values are calculated. Hereinafter, this average value is referred to as a minimum voltage value Vst0.

Next, in step 116, it is determined whether there is any temperature in each address of the nonvolatile memory that is lower than a predetermined temperature (for example, 5 ° C.), in other words, whether there is a minimum voltage value Vst ^* acquired at a low temperature. to decide. In general, the output characteristics of a lead battery become more sensitive to temperature as the temperature becomes lower. In particular, the sensitivity is large at less than 5 ° C. and easily causes a Vst error. Need not be.

  When a negative determination is made in step 116, in step 118, as in step 104, the OCV of the lead battery 20 after being left for 6 hours or longer is measured to detect engine start. In the next step 120, as in step 106, the minimum voltage value Vst is detected, and the temperature T of the lead battery 20 at that time is captured. However, unlike step 106, in step 120, since five sets of data have already been recorded in the nonvolatile memory and there is no need to count the number of times of recording in the nonvolatile memory, the counter N_Vst is not incremented. .

In the next step 122, it is determined whether or not the temperature T fetched in step 120 is higher than the temperature in each address of the nonvolatile memory, in other words, the minimum value of the temperature of each address. In order to obtain the lowest voltage value Vst at a temperature higher than the lowest value of the temperature of each address, the process returns to step 114. When the determination is affirmative, the lowest voltage value Vst ^* is set in step 124 as in step 110. calculated, at a next step 126, the minimum voltage value Vst ^* corresponding thereto and the lowest value of the temperature in the non-volatile memory, overwriting the lowest voltage value Vst ^* calculated by the temperature T and the step 124 fetched in step 120 Then, the process returns to step 114.

On the other hand, when a negative determination is made in step 116, in step 128, the lowest voltage value Vst0 calculated in step 114 is recorded in the nonvolatile memory as the decided lowest voltage value, and the Vst0 decision processing routine is terminated. At this time, when the memory capacity is small, the temperature and the minimum voltage value Vst ^* of each address described above are erased, and only the minimum voltage value Vst0 is recorded at a specific address (for example, memory address 1 described later). It may be.

In the above-described Vst0 determination processing routine, the minimum voltage value Vst0 is determined when there is no Vst acquisition temperature in the non-volatile memory lower than 5 ° C. When the condition that the minimum voltage value Vst0 is determined after 3 months is added, the deterioration of the lead battery 20 before the determination of the minimum voltage value Vst0 is avoided, or the stable voltage is 12.5V or more while the vehicle is left By adding a condition such as performing the minimum voltage value Vst measurement only, the error of the minimum voltage value Vst0 can be reduced. FIG. 4 is based on the premise that the minimum voltage value Vst ^* is recorded in the nonvolatile memory. This is because Vst0 is calculated when the power supply is restarted or when the battery state is calculated. Although the minimum voltage value Vst0 is an important parameter that is a criterion for deterioration determination, it can be measured only when the lead battery 20 is in a new state. Therefore, as shown in this example, there is no problem even if the microcomputer is reset. The minimum voltage value Vst0 or the minimum voltage value Vst ^* is preferably recorded in the nonvolatile memory.

As described above, the Vst0 determination processing routine determines whether or not the predetermined address of the nonvolatile memory is in a null state without writing when power is supplied from the lead battery 20 to the battery diagnostic device 10. Although it is executed at the time of determination, in the case of negative determination, instead of step 102, the lowest voltage value Vst ^* written in each address of the nonvolatile memory is read and the number is used as the current counter N_Vst value. After executing the process, the process proceeds to step 104.

<Diagnostic routine>
The CPU executes a diagnosis routine for diagnosing the battery state (deterioration state) of the lead battery 20 using the minimum voltage value Vst0 recorded in the nonvolatile memory. Such a diagnostic routine can be executed at an arbitrary point of time. For example, it is preferable that the diagnostic routine can be displayed or notified when the engine is stopped or before the engine is started. Note that the CPU reads out the lowest voltage value Vst0 (or five lowest voltage values Vst ^* ) from the nonvolatile memory and expands it in the RAM when the power supply is restarted and when the lead battery 20 is diagnosed. The processing of this diagnostic routine is common to the processing shown in the specific steps of the above-described Vst0 determination processing routine, and the description thereof is duplicated. Therefore, the contents already described will be briefly described below by showing the steps. .

As in steps 104 and 106, the CPU detects the OCV in the stable state of the lead battery 20 and the lowest voltage value Vst at the time of engine start, and calculates the lowest voltage value Vst ^* as in step 110. Next, a voltage difference between the lowest voltage value Vst ^* calculated most recently with respect to the lowest voltage value Vst0 developed in the RAM is calculated. When the calculated voltage difference is less than a first predetermined value (for example, 0.8 V), it is determined that the lead battery 20 is healthy (not deteriorated), and the calculated voltage difference is within a predetermined range (for example, When 0.8V ≦ voltage difference ≦ 1.0V), it is determined that the lead battery 20 (deterioration state thereof) needs attention, and the calculated voltage difference exceeds a second predetermined value (for example, 1.0V). Sometimes it is determined that the lead battery 20 needs replacement.

  Such a determination result is notified to the user (driver) by the display unit and the sound emitting unit described above. For example, when it is determined that the lead battery 20 is healthy, the CPU determines that the lead battery 20 is in need of attention without activating the display unit and the sound emitting unit because it is not necessary to alert the user. When, for example, one yellow LED among the four LEDs 1 is blinked, the buzzer is activated for a predetermined time (for example, 2 minutes) after the engine is stopped to alert the user. When the push switch 2 of the input unit is pressed when it is determined that the lead battery 20 is in need of attention, the user knows that the lead battery 20 is in need of attention and does not wish to be notified by the buzzer. As a thing, you may make it not operate a sound emission part after that. When it is determined that the lead battery 20 needs to be replaced, one of the four LEDs 1 is turned on, for example, one red LED is turned on, and the buzzer is turned on for a predetermined time after the vehicle stops or the engine stops (for example, two minutes). To alert the user. In the case of this determination result, unlike the case requiring caution, even if the push switch 2 of the input unit is pressed, the sound emitting unit may be activated each time a diagnosis is made in order to call the user's attention.

  Further, since the CPU detects the OCV and temperature in the stable state of the lead battery 20, the OCV obtained by correcting the temperature of the OCV is calculated, and the relational expression or table between the OCV and the charged state after the temperature correction is referred to. The state of charge can be determined. You may make it display the charge condition determined in this way using four LED1.

(Effects etc.)
Next, the operational effects of the lead battery with the battery diagnostic device of the present embodiment will be described focusing on the operational effects of the battery diagnostic device.

The battery diagnostic apparatus 10 (the CPU of the arithmetic unit thereof) records five sets of the minimum voltage value Vst ^* and temperature data in the nonvolatile memory (step 112), and then any one of the temperatures recorded in the nonvolatile memory is 5 It is determined whether the temperature is lower than ° C. (step 116) and whether the engine is started at a temperature higher than the temperature recorded in the nonvolatile memory (step 122). The voltage value Vst ^* and the high temperature are overwritten in the nonvolatile memory (step 126). For this reason, the minimum voltage value Vst ^* at the start of the engine at a low temperature with a large variation is excluded from the reference for calculating the minimum voltage value Vst0 of the new battery, so that the deterioration state of the lead battery 20 can be accurately diagnosed. it can.

Further, the battery diagnostic apparatus 10 overwrites the set of the minimum voltage value Vst ^* and the temperature corresponding to the lowest temperature among the five sets of the minimum voltage value Vst ^* and the temperature recorded in the nonvolatile memory ( Step 122), the diagnostic accuracy of the deterioration state of the lead battery 20 can be improved.

Furthermore, the battery diagnostic device 10 calculates the minimum voltage value Vst ^* by correcting the minimum voltage value Vst by temperature correction and OCV correction (step 110), and also performs the latest temperature correction and OCV correction in the diagnosis routine in the same way. Since the comparison is made with the minimum voltage value Vst ^* , it is possible to eliminate the influence on the temperature and OCV of the lead battery 20 and improve the diagnosis accuracy of the deterioration state. In addition, since the average value of the five lowest voltage values Vst ^* is used as a reference for deterioration diagnosis as the lowest voltage value Vst0, the reliability can be improved as compared with the case where the lowest voltage value Vst ^* acquired under a specific condition is used. it can.

  Therefore, the lead battery 20 equipped with such a battery diagnostic device 10 can accurately diagnose the deterioration state by itself and does not require current measurement (such as a current sensor for detecting a large current at the time of engine start). Therefore, it can be supplied to users at low cost.

  In the present embodiment, the battery diagnosis device in a form independent of (not communicating with) the vehicle (automobile) ECU has been described. However, the present invention is not limited to this, and the vehicle ECU functions as the battery diagnosis device. Alternatively, the present invention may be applied to a battery diagnostic apparatus that is separate from the vehicle ECU but can communicate with the ECU. That is, in this embodiment, in order to reduce the cost, an example in which the engine start is determined only by the voltage has been shown. However, for example, the battery diagnostic device monitors the current (for example, the predetermined current value from the lead battery 20). An on-state (positioned at the ON / ACC terminal) in which the engine start is detected (by determining whether or not the above current has flowed) or the ignition switch outputs a battery diagnostic device that is separate from the ECU or ECU. The ignition switch state may be acquired by receiving a high level signal, a low level signal in the OFF state (positioned at the OFF terminal), and the engine start may be detected based on the acquired information.

Further, in the present embodiment, after 5 sets of data of the minimum voltage value Vst ^* and temperature are recorded in the nonvolatile memory, whether any of the temperatures recorded in the nonvolatile memory is lower than 5 ° C., and An example is shown in which it is determined whether or not the engine has started at a temperature higher than the temperature recorded in the nonvolatile memory, and when both are affirmative, the minimum voltage value Vst ^* and the higher temperature are overwritten in the nonvolatile memory. However, the present invention is not limited to this. For example, when the lead battery 20 is new, it is determined whether or not the engine is started at a temperature higher than the temperature recorded in the volatile memory. When the determination is affirmative, the minimum voltage value Vst ^* and the higher temperature are determined. The minimum voltage value Vst ^* corresponding to the lowest temperature and the temperature may be rewritten (overwritten).

Furthermore, in the present embodiment, an example is shown in which the minimum voltage value Vst ^* subjected to temperature correction and OCV correction is recorded in the nonvolatile memory. However, the minimum voltage value Vst before temperature correction and OCV correction is recorded as the temperature and the OCV correction. It may be recorded together with the OCV in a non-volatile memory, temperature correction and OCV correction are performed in the diagnostic routine, the lowest voltage value Vst ^* is calculated, and the lowest voltage value Vst0 is obtained.

  Next, the lead battery with a battery diagnostic apparatus of the Example produced according to the said embodiment is demonstrated. In addition, it describes together about the lead battery with a battery diagnostic apparatus of the comparative example produced for the comparison.

(Example)
The battery diagnosis device with a lead battery using the 55B24 lead battery 20, mounted on a gasoline vehicle of 2000cc in winter, 3 months device collected after the minimum voltage value of the internal data retrieval nonvolatile memory Vst ^* and temperature And the standard deviation of the minimum voltage value Vst ^* and the minimum voltage value Vst0 were calculated. The results are shown in Table 1 below. The standard deviations of the five minimum voltage values Vst ^{* in} Table 1 were small so as not to be a big problem in judging deterioration.

(Comparative example)
In the comparative example, the Vst0 determination processing routine shown in FIG. 6 is executed by the CPU instead of the Vst0 determination processing routine shown in FIG. 4, and the same lead battery with a battery diagnostic device as in the embodiment is the same as the embodiment in winter. Installed in a 2000 cc gasoline vehicle of the vehicle type, collect the device after 3 months, take out the non-volatile memory, read out the minimum voltage value Vst ^* and temperature of the internal data, standard deviation and minimum voltage value Vst0 of the minimum voltage value Vst ^* Was calculated. The results are shown in Table 2 below. Note that the routine shown in FIG. 6 lacks steps 116 to 126 in FIG. The Vst deviation is close to 0.5 V, and the variation is larger than that in the example. The reliability of the value of the lowest voltage value Vst0 calculated based on this is considered to be lower than that in the example.

  Since the present invention provides a battery diagnostic device with high diagnostic accuracy and a battery equipped with the device, it contributes to the manufacture and sale of battery diagnostic devices and batteries, and thus has industrial applicability.

10 Battery diagnostic device 20 Lead battery with battery diagnostic device (lead battery)

Claims (9)

In a battery diagnostic device for diagnosing the battery state of a battery mounted on a vehicle,
A non-volatile memory for storing the battery data;
Voltage measuring means for measuring the voltage of the battery;
Temperature measuring means for measuring the temperature of the battery;
An engine start detecting means for detecting engine start by detecting whether the voltage measured by the voltage measuring means has a voltage drop equal to or higher than a predetermined voltage value;
Minimum voltage acquisition means for acquiring a minimum voltage value Vst at the time of starting the engine in a new state of the battery from the voltage measured by the voltage measurement means;
Temperature acquisition means for acquiring the temperature of the battery at the time of starting the engine or before and after the engine from the temperature measured by the temperature measurement means;
Recording means for recording the minimum voltage value Vst acquired by the minimum voltage acquisition means and the temperature acquired by the temperature acquisition means in the nonvolatile memory;
After the recording means records the minimum voltage value Vst and temperature in the nonvolatile memory, when the engine start is detected by the engine start detection means, or after that, from the temperature recorded in the nonvolatile memory It is determined whether or not the engine is started at a high temperature, and when the determination is affirmative, the minimum voltage value Vst acquired by the minimum voltage acquisition unit and the high temperature acquired by the temperature acquisition unit are used as the nonvolatile memory. Overwriting control means for controlling the recording means to overwrite
A battery diagnostic device comprising:   In the nonvolatile memory, a plurality of sets of the minimum voltage value Vst and temperature are recorded by the recording means, and the overwriting control means is configured to detect the engine start by the engine start detection means, or after that, It is determined whether any temperature recorded in the non-volatile memory is lower than a predetermined temperature, and whether the engine is started at a temperature higher than the temperature recorded in the non-volatile memory. When both are affirmative, the recording means is controlled to overwrite the non-volatile memory with the minimum voltage value Vst acquired by the minimum voltage acquisition means and the high temperature acquired by the temperature acquisition means. The battery diagnostic apparatus according to claim 1.   The overwriting control means overwrites the set of the minimum voltage value Vst and temperature corresponding to the lowest temperature among the plurality of sets of the minimum voltage value Vst and temperature recorded in the nonvolatile memory. The battery diagnostic apparatus according to claim 2, wherein the recording unit is controlled.   Open circuit voltage detection means for detecting the open circuit voltage OCV of the battery is further provided, and the recording means records the OCV before the engine start detected by the open circuit voltage detection means in the nonvolatile memory. The battery diagnostic apparatus according to any one of claims 1 to 3, wherein   The open circuit voltage detection means for detecting the open circuit voltage OCV of the battery, the minimum voltage value Vst acquired by the minimum voltage acquisition means, and the OCV before the engine start detected by the open circuit voltage detection means. And a Vst-OCV correction unit that performs OCV correction to a value at a reference OCV, and the recording unit records the lowest voltage value Vst corrected by the Vst-OCV correction unit in the nonvolatile memory. The battery diagnostic apparatus according to any one of claims 1 to 3, wherein   Vst-temperature correction means for correcting the minimum voltage value Vst acquired by the minimum voltage acquisition means to a value at a reference temperature using the temperature acquired by the temperature acquisition means; 4. The battery diagnostic apparatus according to claim 1, wherein a minimum voltage value Vst corrected by the Vst−temperature correction unit is recorded in the nonvolatile memory. 5.   When the engine start is detected by the engine start detection means, or after that, the latest voltage of the battery measured by the voltage measurement means and the minimum voltage value Vst recorded in the nonvolatile memory by the recording means Battery state diagnosis means for diagnosing the battery state of the battery by comparing the battery state, and the battery state diagnosis means sets the minimum voltage value Vst at least during power supply restart and battery state diagnosis. The battery diagnostic device according to claim 1, wherein the battery diagnostic device is read from the nonvolatile memory.   At least one of a current measurement unit that measures a current flowing through the battery and an information acquisition unit that acquires position information of an ignition switch of the vehicle is further provided, and the engine start detection unit is measured by the voltage measurement unit By detecting whether the voltage has a voltage drop greater than or equal to a predetermined voltage value and the current measured by the current measuring means has a current increase greater than or equal to a predetermined current value, or of the ignition switch acquired by the information acquisition means The battery diagnosis apparatus according to any one of claims 1 to 7, wherein engine start is detected based on position information.   A battery comprising the battery diagnostic device according to claim 1.

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