JP2005274214A - Residual capacity detection device of vehicle battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a residual capacity detection device of a vehicle battery capable of improving accuracy of residual capacity estimation. <P>SOLUTION: This device has a voltage detector 8 for detecting a terminal voltage of a battery 1; a current detector 7 for detecting a discharge current I; an internal resistance detection means A1 for determining an internal resistance R of the battery 1; a deterioration mode determination means A2 for determining a deterioration mode from the present internal resistance R and the terminal voltage V by using a deterioration mode setting map map1 wherein a primary correlation mode wire N between the internal resistance and the terminal voltage of the battery, the first battery deterioration mode area nI below the primary correlation mode wire N, and the second battery deterioration mode area nII over the primary correlation mode wire are set; and a residual capacity detection means A3 for determining the residual capacity Q from the present internal resistance R by using a residual capacity setting map map2 wherein the residual capacity Q of the battery corresponding to the internal resistance R is set corresponding to the first and second battery deterioration modes nI, nII. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vehicle battery remaining capacity detection device capable of accurately detecting the remaining capacity of a battery mounted on a vehicle.

The role of the battery, which is a key component of the vehicle power supply system, is becoming more and more important, such as the role of the ECU backup power source, the driving of the electric load when the engine is stopped at the idling stop, from the old engine start .
Therefore, for example, a hydrometer type remaining capacity detection device is employed, and in this case, the battery specific gravity and the degree of charge SOC (= remaining capacity / full charge capacity in the current deteriorated state × 100 {%]) are shown in FIG. It uses that there is a linear relationship. Note that the a1 and a2 lines in FIG. 5 indicate the characteristics of batteries having different capacities.

In this remaining capacity detection device, a hydrometer type sensor using a float and a reed switch is attached to one of a plurality of cells of a battery, and an ON signal is output at an appropriate specific gravity or more, that is, an appropriate charge degree SOC or more. Yes.
Further, Japanese Patent Application Laid-Open No. 58-123479 (Patent Document 1) calculates the internal resistance of the battery from the voltage between the battery terminals and the battery discharge current during cranking, and the battery terminal voltage and the discharge current immediately before cranking. A technique for detecting the remaining battery capacity based on the internal resistance is disclosed. Japanese Patent Application Laid-Open No. 07-260904 (Patent Document 2) discloses a technique for obtaining a battery remaining capacity using an internal resistance-residual capacity map using the calculated internal resistance of the battery as a parameter.

JP 58-123479 A JP 07-260904 A

However, since the residual capacity detection device of the specific gravity detection method is a lead SW type, the output is ON / OFF, and the value (large or small level) of the residual capacity cannot be known.
Furthermore, the method of estimating the remaining capacity only from the battery internal resistance as in Patent Documents 1 and 2 has a problem that the detection error is large. That is, the lead battery has different deterioration modes depending on the use environment, and the correspondence relationship between the internal resistance and the remaining capacity varies depending on the deterioration mode, but this is not taken into consideration.

The present inventor pays attention to this point, determines the deterioration mode of the battery, and considers the deterioration mode, and estimates the remaining capacity corresponding to the internal resistance, thereby improving the accuracy. I thought.
Here, as a typical deterioration mode of lead battery, overcharge like a vehicle with many high-speed running, lattice corrosion occurs when there is a lot of high temperature use, and repeated deep charge and discharge like a taxi or an automobile with an idling stop function. It is known that softening of the positive electrode active material occurs when the amount is large, and hardening of the negative electrode active material (sulfation) occurs when the shallow charge / discharge cycle is frequent.

  Therefore, the present inventor measured and compared the correlation between the internal resistance R and the remaining capacity Q corresponding to each of the above three deterioration modes, and obtained characteristics as shown in FIG.

  In creating the internal resistance R-remaining capacity Q data diagram, one of the batteries 1 as a plurality of specimens having the same characteristics is used for a predetermined elapsed time so as to cause a deterioration mode of softening of the positive electrode active material, and thereafter A correlation between the internal resistance R and the remaining capacity Q was measured, and a data string P1 indicated by Δ in FIG. 3 was obtained. Further, the other one of the batteries 1 as a device under test is used for a predetermined elapsed time so as to generate a lattice corrosion deterioration mode, and the correlation between the internal resistance R and the remaining capacity Q thereafter is measured. A data string P2 indicated by a mark was obtained.

  Further, another one of the batteries 1 is used for a predetermined elapsed time so as to cause a deterioration mode of curing of the negative electrode active material, and the correlation between the internal resistance R and the remaining capacity Q is measured thereafter, and is indicated by x in FIG. A data string P2 was obtained.

  That is, in the deterioration mode of the positive electrode active material softening (hereinafter referred to as the first deterioration mode), the correlation between the internal resistance R and the remaining capacity Q is represented by the data string P1 in FIG. In (hereinafter referred to as the second deterioration mode), it was confirmed that the correlation between the internal resistance R and the remaining capacity Q is represented by a common data string P2.

  Furthermore, the present inventor measured and compared the correlation between the internal resistance R and the open voltage V (terminal voltage before cranking) corresponding to each of the above three deterioration modes using the same method as described above, and FIG. The characteristics shown were obtained.

That is, in the battery 1 in the deterioration mode of the positive electrode active material softening (that is, the first deterioration mode), each measured value is measured in the internal resistance R-open voltage V map when the battery is new, that is, the battery deterioration degree SOH (= (The full charge capacity in the presently deteriorated state / initial full charge capacity × 100 [%]) is obtained in the region NI below the initial correlation mode line N of the internal resistance R and the open voltage V at the time of 100 [%]. In the battery 1 in the deterioration mode of corrosion or negative electrode active material hardening (that is, the second deterioration mode), it has been found that each measured value is obtained in the region NII above the initial correlation mode N.
The present invention has been devised based on the above-mentioned focus and experimental analysis results, and can improve the accuracy of battery remaining capacity estimation.

  According to a first aspect of the present invention, there is provided a remaining capacity detecting device for a vehicle battery, a voltage detector for detecting a terminal voltage of the battery, a current detector for detecting a discharge current of the battery, the voltage detector, and the current. Internal resistance estimation means for obtaining the internal resistance of the battery from the terminal voltage and discharge current of the battery detected before and during cranking by the detector, and an initial correlation between the internal resistance of the battery and the remaining capacity of the battery Using a deterioration mode setting map in which a mode line and a first battery deterioration mode region that is lower than the initial correlation mode line and a second battery deterioration mode region that is higher than the initial correlation mode line are set, the current internal resistance and the battery terminal A deterioration mode determination means for determining a deterioration mode from the voltage, and a remaining capacity of the battery corresponding to the internal resistance is the first Using the remaining capacity setting map which is set respectively in accordance with the Tteri degraded mode and the second battery degraded mode, characterized in that it has a remaining capacity detecting means for determining the remaining capacity than the current internal resistance, a.

  According to a second aspect of the present invention, in the vehicle battery remaining capacity detecting device according to the first aspect, a display for displaying the remaining capacity of the battery obtained by the remaining capacity detecting means is additionally provided.

  According to the first aspect of the present invention, the internal resistance of the battery is obtained from the terminal voltage and discharge current of the battery, the deterioration mode is determined from the current internal resistance and terminal voltage using the deterioration mode setting map, and the determined deterioration mode is determined. Since the remaining capacity of the battery corresponding to the current internal resistance is obtained using the remaining capacity setting map according to the above, the accuracy of the remaining capacity estimation can be improved.

  According to the second aspect, the remaining capacity of the battery corresponding to the current internal resistance can be displayed by the display, and the remaining capacity can be displayed with reliability.

Hereinafter, a remaining capacity detection device for a vehicle battery according to an embodiment of the present invention will be described. FIG. 1 shows an overall configuration of a remaining capacity detection device for a vehicle battery (hereinafter referred to as a remaining capacity detection device for a battery), and FIG. 2 shows a block diagram of a control function unit of the remaining capacity detection device for a battery 1.
A battery remaining capacity detection device is mounted on a vehicle (not shown) and connected to a pair of batteries (hereinafter referred to as batteries) 1a and 1b connected in series with each other and a positive terminal 2 of a battery 1b on the high potential side via a feeder line 3. Starter 4 and on-vehicle electric load 5, current detector (hereinafter referred to as current sensor) 7 interposed in the feed line 3, and a pair of voltages for detecting the voltage value of the positive terminals of the pair of batteries 1 A detector 8, an engine control unit (hereinafter referred to as ECU) 6, and a display 9 connected to the ECU 6 are provided.

The ECU 6 has a number of ports in an input / output circuit (not shown). When attention is paid only to the control components of the power supply system, the display 9 is connected to the output port, the current sensor 7 is connected to the input port, and the voltage detection is performed. The device 8 is connected.
Here, the display 9 may be a level gauge capable of continuous display, and here, a liquid crystal display is adopted.
The current sensor 7 detects a discharge current discharged to the starter 4 and the vehicle-mounted electric load side, and inputs a current value to the ECU 6.

Each voltage detector 8 detects the voltage value of the plus terminal of each battery 1 according to a predetermined detection time, and inputs the voltage value V to the ECU 6.
In the present embodiment, the remaining capacity of each of the battery 1a and the battery 1b is detected using the same means. Hereinafter, only the battery 1a will be described as the battery 1.

  As shown in FIG. 2, when focusing on only the control function of the power supply system, the ECU 6 serves as a display control unit A4 that controls the internal resistance estimation unit A1, the degradation mode determination unit A2, the remaining capacity detection unit A3, and the display 9. Has a control function. The display 9 and the display control unit A4 that controls the display 9 constitute display means.

The internal resistance detection means A1 detects the internal voltage of the battery 1 from the terminal voltage terminal voltages V ₁ and V ₂ and the discharge currents I ₁ and I ₂ detected before and during the cranking by the voltage detector 8 and the current sensor 7. The resistance R {= | (V ₁ −V ₂ ) / (I ₁ −I ₂ ) |} is obtained.

The deterioration mode determination means A2 includes an internal resistance R in the initial stage of the battery _1, an initial correlation mode line N of the terminal voltage V1 of the battery 1, a first battery deterioration mode region nI lower than the initial correlation mode line N, and an initial correlation mode line N. using degraded mode setting map map1 of the second battery degraded mode range nII is set greater than, determines the current degraded mode range nI or nII than the internal resistance R and the terminal voltage V _1. An example of the deterioration mode setting map map1 here is shown in FIG.

The deterioration mode setting map map1 is set in consideration of the fact that the deterioration mode of the battery 1 differs depending on the usage mode of the vehicle as described with reference to FIG.
That is, as described with reference to FIG. 6, the initial correlation mode line N of the internal resistance R of the battery 1 when it is new and the terminal voltage V of the battery 1 is set based on the data when the battery 1 is new before shipment from the factory. .

Furthermore, it is estimated that the battery 1 reaches the first battery deterioration mode region nI that is the RV region below the initial correlation mode line N with time when the battery has softened the positive electrode active material. It is estimated that the reason why the second battery deterioration mode region nII, which is the RV region above the correlation mode line N, has been reached with time is that lattice corrosion or negative electrode active material hardening (sulfation) has occurred. Is done. Based on such degradation characteristics, using a degraded mode setting map map1, the current internal resistance R and the first from the position e of the terminal voltage V ₁ of the battery 1, it is possible to determine the second battery degraded mode range nI or nII it can.

The remaining capacity detection means A3 uses the remaining capacity setting map map2 in which the remaining capacity Q of the battery corresponding to the internal resistance R is set according to the first battery deterioration mode nI and the second battery deterioration mode nII, respectively, and the current internal resistance The remaining capacity Q is obtained from R. An example of the remaining capacity setting map map2 here is shown in FIG.
As described with reference to FIG. 3, the remaining capacity setting map map2 is created based on the internal resistance R-remaining capacity Q data diagram measured in advance.

That is, the calculation diagram p1 of the remaining capacity Q in the first battery deterioration mode nI in FIG. 2 is set using the data string P1 in the deterioration mode by softening of the positive electrode active material shown in FIG. 3 as a reference. . Similarly, the calculation diagram p2 of the remaining capacity Q in the second battery deterioration mode nII is set based on the data string P2 in the deterioration mode due to lattice corrosion or negative electrode active material hardening (sulfation) shown in FIG. It was.
The display control unit A4 (the control unit of the display means) receives the remaining capacity Q which is the calculated value from the remaining capacity detection means A3, and outputs a display drive signal corresponding to the remaining capacity Q to the display 9 of the display means. As a result, the display 9 displays the remaining capacity Q.

Since the remaining capacity detection device for a vehicle battery according to an embodiment of the present invention has the above-described configuration, the operation thereof will be described below based on each flowchart shown in FIG.
First, when it is detected that an engine key switch (not shown) is turned on, the process proceeds from step s1 to step s2, and data such as voltage V ₁ and current I ₁ from each sensor is captured.

  Next, in step s3, it is determined whether or not there is an engine start signal. Here, when an ignition switch (not shown) is on, it is determined that there is an engine start signal. If there is an engine start signal (that is, during engine cranking), the process proceeds to Yes in step s4. If there is no engine start signal (that is, before engine cranking), the process proceeds to step s5 with No, and returns to step s3 until the key switch is turned off.

When step s4 is reached with an engine start signal, the data of voltage V ₂ and current I ₂ immediately after start (during cranking) are taken in, stored in a predetermined storage area of ECU 6, and the process proceeds to step s6.

In step s6, the terminal voltages V ₁ and V _{2 of} the battery 1 and the discharge currents I ₁ and I ₂ detected before and during the cranking by the voltage detector 8 and the current sensor 7 are taken in, and based on these values, The internal resistance R {= | (V ₁ −V ₂ ) / (I ₁ −I ₂ ) |} of the battery 1 is calculated.

In step s7, using degraded mode setting map map1, the current internal resistance R and the first battery degraded mode range lower than the initial correlation mode line N position on degraded mode setting map map1 corresponding to the terminal voltage V ₁ nI Or whether it is the second battery deterioration mode region nII above the initial correlation mode line N, and the process returns to the main routine. In the case where it is on the initial correlation mode line N, here, processing is performed so as to be regarded as the upper side of the initial correlation mode line N. However, the same effect can be obtained even if processing is performed so as to be regarded as the lower side instead. be able to.

When step s8 is reached, it is determined whether or not the battery 1 is in the first battery deterioration mode region nI. If yes, the process proceeds to step s9, and if no, the process proceeds to step s10.
In step s9, assuming that the current deterioration mode is the first battery deterioration mode area nI, the calculation diagram p1 of the remaining capacity Q in the first battery deterioration mode nI of the remaining capacity setting map map2 is selected.

On the other hand, in step s10, assuming that the current deterioration mode is the second battery deterioration mode region nII, the calculation diagram p2 of the remaining capacity Q in the second battery deterioration mode nII of the remaining capacity setting map map2 is selected.
When step s11 is reached from either step s9 or s10, the latest internal resistance R is determined according to the calculation diagrams p1 and p2 of the remaining capacity setting map map2 selected in either step s9 or s10. The remaining capacity Q corresponding to is obtained.

  Next, in step s12, the calculated remaining capacity Q is displayed. In this remaining capacity display process, the latest battery remaining capacity Q is received by the display control unit A4, and a corresponding display signal is output to the display 9 for a predetermined time (for example, 3 seconds) to display the remaining capacity Q. End control.

Thus, paying attention to the fact that the difference between the calculated value of the remaining capacity corresponding to the internal resistance of the battery 1 and the actual value differs depending on the deterioration mode of the battery 1, here, the second battery deterioration mode P2 (lattice corrosion and negative electrode active material) In the deterioration mode of hardening), the remaining capacity Q corresponding to the internal resistance R can be corrected to be large, and conversely, in the first battery deterioration mode P1 (deterioration mode of softening of the positive electrode active material) The remaining capacity Q can be corrected to a smaller value, the appropriate remaining capacity Q can be calculated in consideration of the battery deterioration mode, and the accuracy of the remaining capacity estimation can be improved.
Furthermore, the remaining capacity Q of the battery 1 corresponding to the latest internal resistance R can be displayed by the display 9, and the remaining capacity display with reliability can be executed.

  In the above description, the vehicle battery remaining capacity detection device is mounted on the vehicle that indicates the remaining capacity of the battery to the user by the display. However, in addition to this, ECU control based on the remaining capacity of the battery is performed. The same applies to vehicles to be performed.

1 is an overall schematic configuration diagram of a battery remaining capacity detection device according to an embodiment of the present invention. It is a block diagram which shows the function structure of ECU of the remaining capacity detection apparatus of FIG. FIG. 3 is an internal resistance-residual capacity characteristic diagram corresponding to a first battery deterioration mode P1 and a second battery deterioration mode P2 used by the ECU of the remaining capacity detection device of FIG. It is a flowchart of the main routine which ECU of the remaining capacity detection apparatus of FIG. 1 performs. It is a specific gravity-SOC characteristic diagram of a battery. It is an internal resistance-open voltage characteristic diagram of a battery.

Explanation of symbols

1 Battery 6 ECU
7 current detector 8 voltage detector 9 indicator map1 deterioration mode setting map map2 remaining capacity setting map A1 internal resistance estimation means A2 deterioration mode determination stage A3 remaining capacity detection means A4 display control section (display means)
N initial correlation mode line I discharge current P1 first battery deterioration mode P2 second battery deterioration mode Q1 remaining capacity (by first remaining capacity estimating means)
R Internal resistance V Open voltage (terminal voltage)

Claims (2)

A voltage detector for detecting the terminal voltage of the battery;
A current detector for detecting the discharge current of the battery;
Internal resistance estimating means for determining the internal resistance of the battery from the terminal voltage and discharge current of the battery detected before and during cranking by the voltage detector and the current detector;
An initial correlation mode line of the initial internal resistance of the battery and the battery terminal voltage, a first battery deterioration mode region lower than the initial correlation mode line, and a second battery deterioration mode region higher than the initial correlation mode line are set. Using the deterioration mode setting map, deterioration mode determination means for determining the deterioration mode from the current internal resistance and terminal voltage,
The remaining capacity detecting means for determining the remaining capacity from the current internal resistance using the remaining capacity setting map in which the remaining capacity of the battery corresponding to the internal resistance is set in accordance with the first battery deterioration mode and the second battery deterioration mode, respectively. When,
A remaining capacity detection device for a vehicle battery, comprising: The remaining capacity detection device for a vehicle battery according to claim 1,
An apparatus for detecting a remaining capacity of a vehicular battery, comprising a display for displaying the remaining capacity of the battery obtained by the remaining capacity detecting means.

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