JP5262468B2 - Battery state detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery state detector for accurately determining the necessity of charging a battery. <P>SOLUTION: This battery state detector measures an open circuit voltage of a lead battery, corrects a charging necessity determining threshold preset based on at least one of the temperature of the lead battery or the degree of the deterioration of the lead battery, and compares the open circuit voltage of the lead battery with the corrected charging necessity determining threshold. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

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

  Conventionally, internal resistance, discharge voltage, open circuit voltage, remaining capacity, state of charge, and the like have been used as parameters representing the battery state of a battery or measurement parameters for calculating the battery state. In recent years, the importance of such battery state monitoring and control has increased as the load on the batteries used in automobiles, portable devices, etc. increases.

  In the battery for vehicles such as automobiles, in order to cope with idle stop start (ISS), regenerative charging, etc. performed to reduce exhaust gas, there is a technology to keep the battery in a battery state suitable for these applications. It is desired. Lead batteries are one of the typical batteries that can be applied to these applications.

  For vehicles, a method and an apparatus for calculating a remaining capacity by comparing an open circuit voltage (OCV) when the vehicle is left, an engine starting voltage, or a data map obtained by measuring internal resistance in advance have been proposed. In these techniques, the remaining capacity of the calculation result is compared with a preset threshold value to determine whether or not to stop idling and to notify the necessity of charging (for example, see Patent Document 1). In general, it is considered that a technique for determining the required charge by comparing the OCV while the vehicle is left with a preset required charge determination threshold value is excellent.

JP 2003-264209 A

  The charge required determination threshold value of the conventional battery state detection device is a fixed value set in advance. If the charge-required determination threshold value is fixed, there is a problem that, depending on the temperature and deterioration state of the battery, the engine cannot be started even though the determination is good, or a charge-required alarm is issued unnecessarily.

  In view of the above-described case, an object of the present invention is to provide a battery state detection device that can accurately determine whether a battery needs to be charged.

In order to solve the above problems, the present invention provides a battery state detection device for detecting a battery state of a battery mounted on a vehicle, an open circuit voltage measuring means for measuring an open circuit voltage of the battery, and a temperature of the battery. Based on the voltage of the battery at the time of starting the engine, measured by the voltage measuring means at the time of starting the engine, and by measuring the voltage of the battery at the time of starting the engine. and deterioration determination hand stage determines the degree of deterioration of the battery, the temperature measuring means is needed charge determination threshold is therefore preset in deterioration determination results determined at the measured temperature and the deterioration determining means correcting And comparing the battery open circuit voltage measured by the open circuit voltage measuring means with the corrected threshold value for determination of charge required. A main charging determination means for determining, characterized by comprising a.

  In the present invention, it further comprises storage means for storing the correspondence relationship between the temperature of the battery and the correction amount of the required charge determination threshold value, and the required charge determination means stores the temperature measured by the temperature measurement means in the storage means. The preset charge-requirement threshold value may be temperature-corrected using a correction amount obtained by applying the correspondence relationship. In addition, the deterioration determination result by the deterioration determination means is one of good, caution, and replacement, and the preset charge determination threshold value for good is 12.00 V. The charge determination threshold value may be 12.17V, and the preset charge required determination threshold value required for replacement may be 12.34V.

According to the present invention, the main charge determining means, the main charge determination threshold is therefore preset in deterioration determination results determined at the measured temperature and the degradation determination means temperature measuring means is corrected, Obtaining the effect that the determination of the required charge can be performed accurately according to the temperature and deterioration of the battery when the determination of the required charge of the battery is performed by comparing the open circuit voltage of the battery with the required charge determination threshold. Can do.

  Hereinafter, embodiments of a battery state detection device according to the present invention will be described with reference to the drawings. In addition, in this embodiment, the battery state detection apparatus which detects the battery state of a 14V type | system | group (nominal voltage: 12V) automotive lead battery (for example, 55B24) is illustrated.

  In general, the upper part of the battery case of the lead battery is bonded or welded to a polymer resin upper lid that seals the upper opening of the battery case, and the upper cover is used to supply power to the outside as a power source for automobiles. The two (positive and negative) output terminals are erected.

  As shown in FIG. 1, the battery state detection device 10 of the present embodiment has a substantially thin plate-like casing 6, and a stretch absorption bending portion 5 from one side end in a direction intersecting the longitudinal direction of the casing 6. The conductive member 4 having the above is derived. A ring-shaped terminal portion is formed at the front end portion of the conductive member 4, and the terminal portion is fitted into two output terminals erected on the upper lid of the lead battery, and then screw formed on the output terminal. 1 is fixed to the upper lid (lead battery) from the upper side shown in FIG. For this reason, a space or a groove for accommodating or mounting the casing 6 or the conductive member 4 may be formed in the upper lid of the lead battery, and the battery state detection device 10 may be integrated with the lead battery.

  On the upper surface side of the casing 6, a plurality of light emitting diodes (hereinafter referred to as LEDs) 1 for displaying the battery state of the lead battery are arranged in a row. The upper surface of the casing 6 on which the LED 1 is disposed is covered with a translucent resin cover. In the battery state detection device 10 of this embodiment, when the lead battery is in a good state (when it is not necessary to replace the lead battery), the LED 1 does not light up or blink. Further, the battery state detection device 10 has a built-in coil-type buzzer (not shown) in order to issue a warning to the driver (user) about the battery state, and the position of the casing 6 corresponding to the mounting position of the buzzer is provided. A buzzer sound emitting hole 3 is formed. Further, on the upper surface side of the casing 6, for example, if the driver already understands the battery state of the lead battery due to the sound of the buzzer and does not wish to sound the buzzer after the next time, the battery indicates that the sound of the buzzer is not desired. An operation button 2 for instructing the state detection device 10 is arranged.

  In the casing 6, a voltage measuring unit configured by an AD converter, a reference power source, etc., for measuring the voltage of the lead battery, a temperature measuring unit configured by an AD converter, a thermistor, etc., for measuring the temperature of the lead battery, a CPU, a ROM, a RAM , A calculation unit configured with a non-volatile EEPROM or the like, a notification unit configured with a transistor or a resistor for operating the buzzer described above, and an operation button control unit for controlling the operation button 2 A substrate having a display control unit configured to include a transistor, a resistor, and the like, and to turn on or blink the LED 1 to display whether the lead battery is in a state of caution (for battery replacement) or in a state of need for replacement Is built-in. The operating power of the battery state detection device 10 is supplied from the lead battery via the conductive member 4.

  The CPU of the calculation unit (hereinafter referred to as CPU) captures the voltage of the lead battery via the voltage measurement unit every predetermined time (for example, 2 ms), and monitors the captured voltage, so that the lead battery is not in operation or charged. Determine if it is discharging. The voltage of the lead battery becomes an open circuit voltage (OCV) when it is determined that the battery is not operating (preferably, when a predetermined time (for example, 6 hours) at which the polarization of the lead battery is eliminated from the time when the determination is made). It should be noted that when the engine is started, the voltage drops rapidly and then recovers. Therefore, by grasping the lowest value of the acquired voltage, the lowest voltage Vst at the time of starting the engine (hereinafter referred to as the engine starting voltage) can be obtained. Yes (see FIG. 2). Moreover, CPU takes in the temperature of a lead battery via a temperature measurement part for every predetermined time (for example, 1 s).

  The CPU determines the degree of deterioration of the lead battery. FIG. 2 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. 2, the engine start voltage of the lead battery in a non-degraded state is represented by Vst0, and the engine start voltage after degradation is represented by Vst. In FIG. 2, as the lead battery deteriorates, the voltage difference ΔVst (= Vst0−Vst) between the engine start voltage Vst0 in the non-deteriorated state and the engine start voltage Vst after deterioration increases.

  Therefore, for example, the engine start voltage Vst0 of the lead battery in a non-deteriorated state is stored in the EEPROM, and the engine start voltage Vst0 is read and compared with the (most recent) engine start voltage Vst after deterioration. Can be determined. In the determination, two threshold values are provided for the voltage difference ΔVst (for example, as shown in Table 1 described later, values of 0.5 V and 0.9 V are stored in the ROM as a program or program data). The deterioration determination result may be performed in one of three cases: good, attention required, and replacement.

  Further, the CPU corrects the charge required threshold value based on the temperature and deterioration determination result of the lead battery, and compares the open circuit voltage of the lead battery with the corrected charge required threshold value to charge the lead battery. Make a decision. The ROM stores a correspondence relationship (for example, a map or a mathematical expression) between the temperature of the lead battery and the correction amount of the charge-required determination threshold value, and the correspondence relationship is developed in the RAM at the initial setting. The CPU corrects the charge required determination threshold value by using a correction amount obtained by applying the actually measured temperature of the lead battery to the correspondence relationship. In addition, when the deterioration determination result is classified into the above-described good, caution required, and exchange required, the good charge determination threshold is 12.00 V and the charge required determination threshold is 12. 17V, the threshold value for determining the charge required for replacement is set to 12.34V, the threshold value for determining the necessity is stored in the ROM, and is expanded in the RAM at the initial setting for determining whether the lead battery needs to be charged. To be served.

  As shown in FIG. 3, the engine start voltage Vst−the vehicle left-over OCV characteristic varies depending on the deterioration degree and temperature of the lead battery. A dark current of several mA to several tens of mA actually flows while the vehicle is left, but it can be handled as being almost equal to OCV. The OCV is an amount corresponding to the remaining capacity, and the remaining capacity may be measured and handled instead of the OCV.

  Since the battery state detection device 10 of the present embodiment makes a determination of a required charge based on a comparison between the OCV while the vehicle is left and a required charge determination threshold, the required charge determination threshold is Vst in the engine start voltage Vst-OCV diagram. This is defined by adding a margin to the OCV just before the value drops greatly. The margin is set by adding a condition that, for example, a room lamp and a radio are turned on at night and the engine can be started after a one-hour discharge. If the maximum load assumed to be installed in the target vehicle, for example, it is defined as a capacity that can be discharged for 1 h with a load of 50 W, the margin is calculated as 50 W × 1 h / 12 V = about 4 Ah in terms of remaining capacity. If a value obtained by adding an OCV margin equivalent to 4 Ah to the OCV of the start limit of the automobile lead battery used for 3 years, which is the warranty period, is 12.34V.

  The charge-required determination is used for determining whether or not ISS is possible and for alarming the driver. In the determination of whether or not the ISS is possible, it is only necessary to notify the vehicle-side control device of the result of determining whether the battery state is required by communication, for example, by communication, so that the vehicle-side control device determines whether or not the ISS is acceptable. The LED 1 may be turned on (flashing) or a buzzer may be sounded. In the case where the charge required determination is used for the ISS determination, the vehicle-side control device does not perform idle stop when the charge required determination is made. Further, when an alarm is issued to the driver, the driver can charge the lead battery to avoid the trouble that the engine cannot be started.

  Hereinafter, according to the above-described embodiment, the present invention will be described more specifically with reference to examples and comparative examples.

Example 1
A specific embodiment of the battery state detection device 10 will be described. The temperature is 25 ° C. unless otherwise specified. The following table 1 is a table of setting conditions for the required charging determination threshold value. The required charging determination threshold value is not a fixed value, but is a table in which the required charging determination threshold value is treated as a function of temperature and deterioration.

  The batteries with various deterioration states that have been installed in actual vehicles since the beginning of a new vehicle and normally used for three years were left at different temperatures, and then an engine start test was conducted. Three batteries with different deterioration states were used for the test. Table 2 shows the engine starting voltage Vst value of the battery used in the test, its initial value Vst0, and the voltage difference ΔVst = Vst0−Vst.

  As described above, the voltage difference ΔVst is an amount that can be treated as an indicator of the deterioration state of the battery. Before starting the engine, the battery state detection device 10 made a determination of charging required. In addition, an engine start test was conducted with the battery. Table 3 shows whether or not the engine can be started and the required charging determination result. The engine could be started for all batteries with good charge determination results.

(Example 2)
In the second embodiment, the charging required threshold setting conditions are changed from Table 1 to Table 4 below. In Table 4, the charge required determination threshold is treated as a function of temperature and deterioration. Other conditions were the same as in Example 1.

  The engine start test was conducted using the battery shown in Table 2 in the same manner as in Example 1. The test results are shown in Table 5 below. No. with a relatively low degree of deterioration. 1 and no. In the case of the battery No. 2, there were six cases where the engine could be started due to the determination of charging required. In Example 2, it can be said that it is easier to determine the charge required than in Example 1. However, it is determined that charging is required before the engine cannot be started, and the product is a safe side determination. Since there is a risk that it is necessary and necessary to frequently determine charge, it is desirable to set a threshold for determining charge required in consideration of deterioration as in the first embodiment.

(Comparative Example 1)
In Comparative Example 1, the charge required determination threshold setting condition is a fixed value of 12.34V. When this is expressed in a table like Example 1, it becomes Table 6 below.

  Other conditions were the same as in Example 1. The test results are shown in Table 7 below. No. Although there are cases where the engine cannot be started while the battery 3 is judged good, this is a misjudgment and is not allowed. In order to avoid this problem, it is necessary to increase the threshold value for determining whether charging is required. This battery is not practical because it requires less charge than necessary, particularly at room temperature, with a battery with little deterioration such as battery No. 1.

  From the above results, it can be seen that the battery state detection devices of Examples 1 and 2 are excellent.

  Since the present invention provides a battery state detection device that can accurately determine whether a battery needs to be charged, it contributes to the manufacture and sale of the battery state detection device, and thus has industrial applicability.

It is an external appearance perspective view of the battery state detection apparatus of embodiment which can apply this invention. It is a graph which shows typically engine start voltage Vst0 of a lead battery in a non-deteriorating state, and engine start voltage Vst of a lead battery after deterioration. It is a characteristic diagram which shows the relationship between the engine starting voltage Vst and the open circuit voltage OCV in the new article state of a lead battery (55B24), and a deterioration state.

Explanation of symbols

10 Battery state detection device

Claims (3)

In a battery state detection device for detecting the battery state of a battery mounted on a vehicle,
Open circuit voltage measuring means for measuring the open circuit voltage of the battery;
Temperature measuring means for measuring the temperature of the battery ;
Engine starting voltage measuring means for measuring the voltage of the battery at the time of starting the engine;
And deterioration determination hand stage determines the degree of deterioration of the battery based on the voltage of the battery at the time of the measured engine start by the engine starting voltage measuring means,
The battery in which the temperature of the main charge determination threshold thus preset in the degradation determination results determined at the measured temperature and the deterioration determining means corrects the measurement unit, measured in the open-circuit voltage measurement means Charge determination means for determining whether the battery needs to be charged by comparing the open circuit voltage of the battery and the corrected threshold value for determination of charge required.
A battery state detection device comprising:   Storage means for storing a correspondence relationship between the temperature of the battery and the correction amount of the charge-required determination threshold value is further included, and the charge-required determination means stores the temperature measured by the temperature measurement means in the storage means. The battery state detection device according to claim 1, wherein the preset charge-requirement determination threshold value is temperature-corrected by using a correction amount obtained by applying the stored correspondence relationship.   The deterioration determination result by the deterioration determination means is one of good, caution required, and replacement required, and the preset charge determination threshold value is 12.00 V in good condition, and the preset with caution is required. The battery state detection device according to claim 1, wherein a required charge determination threshold value is 12.17 V, and the preset required charge determination threshold value for replacement is 12.34 V.

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