JP2007038795A - Battery state detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery state detection device capable of carrying out precise state determination without depending upon a battery deteriorated status, etc. <P>SOLUTION: This battery state detection device detects whether a battery 1 is normal or not in consideration of a changing status during a cranking period of an enumerated inside resistance value by enumerating the inside resistance value of the battery 1 in accordance with a detection result of a voltage sensor 23 and an electric current sensor 21 in cranking of an engine. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a battery state detection device that manages the state of a battery.

  In the battery state determination in the conventional battery state detection device, the internal resistance of the battery is measured from the amount of decrease in the output voltage of the battery at the start of the engine and the current value flowing at that time, and based on the measured internal resistance value The degree of deterioration of the battery is determined.

  However, there are various types of battery deterioration conditions, such as when lattice corrosion and sulfation overlap, and depending on the deterioration conditions, the correlation between the actual internal resistance and the open circuit voltage of the battery deteriorates. The correlation between the resistance and the amount of decrease in the battery output voltage at the time of starting the engine may also deteriorate. In this case, accurate state determination becomes difficult with the above-described prior art in which the state determination is performed by directly using the output voltage drop amount.

  Therefore, an object to be solved by the present invention is to provide a battery state detection device capable of accurately determining a state regardless of a deterioration state of the battery or the like.

  In order to solve the above-mentioned problem, in the invention of claim 1, a battery state detection device for managing the state of a battery mounted on an automobile, the voltage sensor for detecting the output voltage of the battery, and the supply from the battery An internal resistance value of the battery is calculated based on a detection result of the voltage sensor and the current sensor at the time of engine cranking, and a cranking period of the calculated internal resistance value And a processing unit that detects the state of the battery in consideration of a change state in the battery.

  According to a second aspect of the present invention, in the battery state detection device according to the first aspect of the invention, the processing unit takes into account the degree of increase in the internal resistance value of the battery during the cranking period. Detect the state of.

  According to the first aspect of the present invention, the internal resistance value of the battery is calculated based on the detection results of the voltage sensor and the current sensor at the time of cranking the engine, and the calculated internal resistance value during the cranking period is calculated. Since the battery status is detected in consideration of the change status, the status of the battery is instantly adapted to the actual status without taking into consideration various conditions such as the battery installation environment such as deterioration status and temperature, and the car model. Can be detected accurately.

  According to the second aspect of the present invention, since the battery state is detected in consideration of the degree of increase in the internal resistance value of the battery during the cranking period of the engine, the state of the battery is accurately determined. Can be detected.

<1. Principle>
As the battery mounted on the automobile, the present applicant changes the remaining charge amount for each of a new battery and a battery in various deteriorated states, and each state where the remaining charge amount is different. The battery was discharged at the time of engine start (predetermined discharge), and the output voltage before and during the battery discharge was measured. And the open circuit voltage value before performing each engine start discharge in each remaining charge state of each battery with different deterioration conditions, and the lower limit voltage value (discharge time voltage value) at the time of engine start discharge I investigated the relationship.

  Here, the engine start discharge is a discharge (or an equivalent discharge) performed when the starter of the automobile is driven and the engine is started. The lower limit voltage value is the lowest value when the output voltage of the battery is reduced due to the discharge at the start of the engine.

  FIG. 1 is a graph of the test results. The horizontal axis corresponds to the open-circuit voltage value of the battery before the start of engine start discharge in each discharge test, and the vertical axis represents during engine start discharge in each discharge test. It corresponds to the lower limit voltage value of the battery. Further, the curve G1 in FIG. 1 is drawn based on the measurement result for a new battery, and the curves G2 to G5 are drawn based on the measurement result for a battery that has been used and deteriorated to some extent. Curves G1 to G5 are obtained as a result of tests on batteries having different deterioration conditions. Among these, the curves G2 to G4 correspond to the batteries that are repeatedly charged and discharged in a manner close to a normal use state, and the use period of the batteries becomes longer and the deterioration progresses in the order of the curves G2, G3, and G4. Curve G5 corresponds to a battery that is frequently overcharged. The curves G4 and G5 have different deterioration conditions (deterioration factors), but the degree of deterioration (deterioration degree) is almost the same.

  Specifically, when attention is paid to the curve G1 corresponding to the new battery, the lower limit voltage value when the engine start-up discharge is performed when the open-circuit voltage value is about 12.9 V (almost fully charged state) is about 9 This indicates that the lower limit voltage value when the engine start-up discharge is performed when the open-circuit voltage value is approximately 12.1V is approximately 8.1V. When attention is paid to the curve G4 corresponding to the battery having deteriorated, the lower limit voltage value when the engine start discharge is performed when the open circuit voltage value is about 12.5V is about 8.1V. ing.

  From the graph of FIG. 1, it is known that the corresponding curves G1 to G5 are shifted in the right direction (or lower right direction) of the graph as the deterioration of the battery proceeds. In particular, in a region where the lower limit voltage value is equal to or lower than a predetermined reference level (for example, 9 V), the rightward shift amount of the curves G2 to G5 with respect to the curve G1 tends to increase as the corresponding battery deteriorates. I know that

  In consideration of this, for example, the point P1 (VO, VL) on the graph of FIG. With reference to the corresponding point P2 (VN, VL), the degree of deterioration of the battery can be determined using the shift amount D shifted in the right direction of the horizontal axis. If the degree of deterioration of the battery is found in this way, the relationship between the open-circuit voltage value and the lower limit voltage value (for example, curves G1 to G5) of the battery can be defined according to the degree of deterioration. By only detecting, it is possible to predict the lower limit voltage value when starting the engine by driving the starter of the automobile. If the voltage level required to drive the starter is found on the other side, the voltage level required to drive the starter is set as the start limit level (for example, the start limit line L01 in FIG. 1). By comparing the predicted lower limit voltage value against the starting limit level, it is determined whether or not the lower limit voltage value is equal to or higher than the starting limit level (start limit line L01), that is, the starter is driven without any problem according to the lower limit voltage value. It is possible to determine whether or not it can be performed.

  However, the present applicant has found that the start limit line L01 has a large variation due to various factors such as the resistance value in the power supply circuit in the automobile, such as the vehicle type and individual differences of the automobile. On the other hand, since the battery is often mounted in common for a plurality of vehicle types, it is not desirable to uniformly determine the start limit line L01 in the combination of the vehicle and the battery mounted on the vehicle.

  Here, as a condition necessary for driving the starter by power supply from the battery, first, as a first condition, it is necessary to secure an operating voltage of the plunger for meshing the gear of the motor of the starter with the engine. is there. Further, as a second condition, it is necessary that the cranking rotational speed at the time of starting the engine (hereinafter referred to as “cranking rotational speed”) is equal to or higher than the engine ignitable rotational speed. Furthermore, as a third condition, it is necessary to maintain the rotational speed during cranking when starting the engine.

  Therefore, in this embodiment, it is actually detected whether or not the above first to third conditions are satisfied, and based on the detection result, it is determined whether or not the battery is normal. Yes. This will be explained.

(1-1. First condition)
As described above, first, as the first condition, it is necessary to ensure the operating voltage of the plunger for meshing the gear of the motor of the starter with the engine. FIG. 2 is a schematic diagram showing an example of a general starter ST. 2, reference numeral 1 denotes a battery, reference numeral 2 denotes a plunger, reference numeral 3 denotes a movable contact of the plunger 2, reference numeral 4 denotes a fixed contact, reference numeral 5 denotes a starter motor, and reference numeral 6 denotes a voltage supplied from the battery 1 to the plunger 2. The ignition switch 7 has an engine gear. When the ignition switch 6 is turned on, the plunger 2 of the starter ST is driven to bring the movable contact 3 into contact with the fixed contact 4, whereby the starter motor 5 is started, and the pinion gear 6b is moved in the direction of the arrow Q via the lever 6a. It moves in the direction and meshes with the gear 7 of the engine so that the rotation of the starter motor 5 can be transmitted to the engine. When the engine starts to rotate, the pinion gear 6b is disengaged from the engine gear. Therefore, it is necessary to secure the operating voltage of the plunger as a minimum.

  In this case, in this embodiment, a prescribed value of the minimum voltage (hereinafter referred to as “plunger drive minimum voltage Vc”) necessary for driving the plunger 2 is referred to, or the plunger drive minimum voltage Vc is measured in advance. In FIG. 3, the lower limit voltage VL appearing at the time T01 when the inrush current flows when the ignition switch 6 for power supply to the plunger 2 is turned on is equal to or higher than the plunger drive minimum voltage Vc (see step S05 in FIG. 17). By determining whether or not there is, it is determined whether or not the first condition is satisfied.

  As described above, when the first condition is satisfied, the starter motor 5 is engaged with the gear 7 of the engine by driving the plunger 2 of the starter ST shown in FIG. In this state, in this state, the rotation speed of the starter motor 5 is decelerated at a predetermined gear ratio (for example, 10: 1) to become the cranking rotation speed.

(1-2. Second condition)
However, even when the plunger 2 is driven without hindrance, the engine is not ignited if the cranking rotational speed is less than the engine ignitable rotational speed. In other words, when the voltage level from the battery 1 is low, the cranking rotational speed is lowered, and it may be impossible to ignite the engine. Therefore, as described above, as the second condition, it is necessary that the cranking rotational speed at the time of starting the engine is equal to or higher than the engine ignitable rotational speed. Therefore, in this embodiment, when starting the engine, the cranking rotational speed is detected, and the detected rotational speed is compared with the engine speed that can be ignited by the engine that has been detected by a standard value or a test in advance. To determine whether the engine can be ignited.

  FIG. 4 is a diagram showing the relationship between the cranking rotational speed and the engine torque. In FIG. 4, the horizontal axis represents the cranking rotational speed, and the vertical axis represents the engine torque. 4, reference characters L02a and L02b are torque-rotation characteristic lines (starter TN characteristic lines) in the starter motor 5, reference numeral L03 is an engine torque-rotation characteristic line (engine TN characteristic line), and reference numeral L04 is engine ignition. This is a possible speed line, and in FIG. 4, the engine ignitable speed is specified as n01.

  In general, the torque of the starter motor 5 has a negative correlation with the rotational speed, but also changes depending on the voltage applied to the starter motor 5. The lower the applied voltage, the lower the torque. For example, a first starter TN characteristic line L02a shown by a solid line in FIG. 4 shows a state in which an appropriate voltage is applied to the starter motor 5, and a second starter TN characteristic line L02b shown by a dotted line is The state where the applied voltage to the starter motor 5 is reduced is shown.

  In a state in which the starter motor 5 shows the first starter TN characteristic line L02a, the cranking rotation speed n02 is determined at the intersection P01 between the first starter TN characteristic line L02a and the engine TN characteristic line L03, and this cranking rotation. Since the number n02 is within the range of the engine ignition possible rotation number n01 or more, the engine can be started.

  On the other hand, in the state where the voltage applied to the starter motor 5 decreases and the second starter TN characteristic line L02b appears, the cranking rotation speed at the intersection P02 between the second starter TN characteristic line L02b and the engine TN characteristic line L03. Although n03 is determined, the cranking speed n03 is less than the engine ignition possible speed n01, so that the engine cannot be started.

  Thus, if the starter TN characteristic lines L02a and L02b, the engine TN characteristic line L03, and the engine ignitable rotation speed line L04 shown in FIG. 4 are known in advance, whether or not the start of cranking is realized. Can be determined.

  However, in general, the viscosity of the lubricating oil used in the starter motor 5 and the engine is significantly affected by the temperature, and there are other conditions such as the vehicle type and individual differences of the automobile, so the starter TN characteristic lines L02a, L02b, The engine TN characteristic line L03 varies greatly depending on various environmental conditions. Accordingly, it is not desirable to uniformly define the starter TN characteristic lines L02a and L02b and the engine TN characteristic line L03. The starter TN characteristic lines L02a and L02b and the engine can be parameterized in consideration of all environmental conditions. Defining the TN characteristic line L03 is too complicated and complicated.

  Therefore, in this embodiment, only the engine ignitable engine speed line L04 having a relatively small numerical variation is held as an eigenvalue, while the cranking engine speed nr is prepared with parameters and the like in FIG. Rather than calculating and calculating the intersection points P01 and P02, the actual cranking speed nr realized when the engine is started is detected, and this cranking speed nr is compared with the engine ignition possible speed n01. To determine whether the engine can be ignited.

  In this embodiment, the cranking speed nr is detected based on the waveform of the voltage applied to the starter motor 5.

  FIG. 5 is a diagram showing how the waveform of the voltage applied to the starter motor 5 changes due to the cranking operation. In the example of FIG. 5, a four-cylinder engine is applied, and reference numeral 10 shown in (a) to (d) in FIG. 5 indicates one engine cylinder portion of the four cylinders. Specifically, (a) in FIG. 5 shows the intake state of the engine cylinder section 10, (b) shows the compressed state, (c) shows the expanded state, and (d) shows the exhaust state. The in-cylinder pressure of the engine cylinder portion 10 corresponds to reference # 1, and the in-cylinder pressures of the other three engine cylinder portions (not shown) correspond to reference numbers # 2 to # 4, respectively. Specifically, the in-cylinder pressure # 1 of the engine cylinder unit 10 increases in the compressed state (b) and decreases in the expanded state (c). There is almost no change in in-cylinder pressure # 1 in the intake state (a) and the exhaust state (d).

  Further, when each engine cylinder portion performs cranking, torque variation as indicated by reference numeral 11 in FIG. 5 occurs along with a change in the cylinder pressure of each engine cylinder portion, and thereby the cranking rotational speed varies, This appears as fluctuations in the back electromotive force in a coil (not shown) in the starter motor 5. This means that vibration occurs in the output voltage of the battery 1. Note that reference numerals 11-1 to 11-4 in FIG. 5 indicate the correspondence between torque fluctuations generated by the operation of the engine cylinder portions and fluctuations in the cylinder pressures # 1 to # 4.

  In this way, considering that the output voltage of the battery 1 (see FIG. 3) corresponding to the reference numeral 11 in FIG. 5 varies in accordance with the change in the cylinder pressure of each engine cylinder during cranking, the battery It was found that the actual cranking speed nr can be detected by observing the vibration waveform appearing in the output voltage 1 and detecting the period of the vibration. Therefore, in this embodiment, the period or frequency of the amplitude of the output voltage of the battery 1 is detected, and the cranking rotation speed nr is detected based on the detection result.

  FIG. 6 is a diagram illustrating an example of a method of detecting the cranking cycle based on the output voltage of the battery 1 (hereinafter referred to as “first detection method”). In the first detection method of FIG. 6, the cranking cycle is detected by the upper and lower peak values of the output voltage 13 of the battery 1. Specifically, first, the output voltage 13 of the battery 1 is cut off in a high frequency band by a low-pass filter to remove noise, and the waveform of the output voltage 13 shown in FIG. 6A is obtained. Then, the output voltage 13 is sampled (quantized), and the result data Vn + 1 is compared with the previous result data Vn. If the result data Vn is increased as shown in FIG. ”Is binarized so that the logical value becomes“ 0 ”when the number is decreased. Then, for the local maximum value of each vibration appearing in the output voltage 13, the trailing edge (low edge) of the binary data appears in FIG. 6B, and for the local minimum value of each vibration, FIG. In, a rising edge (high edge) of binary data appears. Then, for example, the cranking cycle t01 is detected based on, for example, the rising edge (high edge) of the binary data, and the cranking rotation speed nr is calculated based on the cycle t01. Although the rising edge (high edge) of the binary data is used as a reference here, the falling edge (low edge) of the binary data may be used as a reference.

  FIG. 7 is a diagram showing another example of a method of detecting the cranking period based on the output voltage 13 of the battery 1 (hereinafter referred to as “second detection method”). In the second detection method of FIG. 7, the peak / valley of the output voltage 13 of the battery 1 is detected to detect the cranking cycle. Specifically, first, the output voltage 13 of the battery 1 is cut off in a high frequency band by a low-pass filter to remove noise, and the waveform of the output voltage 13 shown in FIG. 7A is obtained. Then, an IIR (Infinite Impulse Response) filter (non-cyclic filter) including exponential smoothing is used for the output voltage 13 of the battery 1 or an FIR (Infinite Impulse Response) filter (cyclic filter) including a moving average is used. Is used to estimate an average trend line (trend change) L05 of the output voltage 13 of the battery 1. Then, the output voltage 13 and the trend line L05 are compared in magnitude. For example, as shown in FIG. 7B, the output voltage 13 is “1” when the output voltage 13 is larger than the trend line L05, and “0” when the output voltage 13 is smaller. Perform binarization. Then, for example, the cranking cycle t01 is detected based on, for example, the fall (low edge) of the binary data, and the cranking rotation speed nr is calculated based on the cycle t01. Here, the falling edge (low edge) of binary data is used as a reference, but the rising edge (high edge) of binary data may be used as a reference.

  FIG. 8 is a diagram showing still another example (hereinafter referred to as “third detection method”) of the method of detecting the cranking period based on the output voltage 13 of the battery 1. In the third detection method of FIG. 8, a discrete Fourier transform (DFT) or a fast Fourier transform (FFT) is performed on the output voltage 13 of the battery 1 to detect the cranking frequency. ing. Specifically, first, a high frequency band is cut off by a low-pass filter of the output voltage 13 of the battery 1 to remove noise, and a waveform of the output voltage 13 shown in FIG. 8A is obtained. Then, the output voltage 13 is sampled (quantized) at a sampling interval Δt to obtain digital data Vi (where i is 0 to N). Thereafter, the frequency distribution as shown in FIG. 8C is obtained by using, for example, the mathematical formula shown in FIG. 8B. Then, the amplitude that appears in the vertical axis direction in FIG. 8C is equal to or greater than a predetermined reference value, and the frequency having the maximum amplitude is defined as the cranking rotation speed nr.

  Thus, the engine can be ignited by comparing the cranking rotational speed nr detected by any one or a combination of the first to third detection methods with the engine ignitable rotational speed n01 which is an eigenvalue. Determine whether or not.

(1-3. Third condition)
However, in actual cranking at the time of starting the engine, in general, the engine does not start with only one rotation. For example, in a four-cylinder engine, the engine starts when cranking is not performed four times in total (see four torque fluctuations 11-2, 11-1, 11-3, and 11-4 in FIG. 5). I know I won't. If the voltage level from the battery 1 is low when the engine is started, the cranking speed gradually decreases during a certain period of cranking when the engine is started, and finally the ignition of the engine There may be situations where it becomes impossible. Therefore, as described above, as the third condition, it is necessary to maintain the rotation speed while cranking at the time of engine start. The following can be considered as means for determining the third condition.

  FIGS. 9 and 10 are graphs showing test results obtained by measuring the time-dependent characteristics of the output voltage and the discharge current when the engine is cranked for a normal battery 1 in a fully charged state. In FIGS. 9 and 10 and the graphs of FIGS. 11 to 14 to be described later, the elapsed time on the horizontal axis corresponds to the start of cranking, and the rear end of the horizontal axis (about 0.6 seconds have elapsed). ) Almost corresponds to the end of cranking.

  Then, when the time-dependent characteristics of the internal resistance value of the battery 1 during the cranking period 15 (see FIG. 3) are derived based on the measurement results of FIG. 9 and FIG. 10, a graph as shown in FIG. 11 is obtained. . Here, the cranking period 15 means that the engine starts from the time T01 when cranking is started by applying voltage to the plunger 2, and the output voltage of the battery 1 (voltage level of the positive terminal of the battery 1) starts cranking. This is the period up to time T02 when the open voltage VO of the previous battery 1 is exceeded. As for the calculation method of the internal resistance value, the open-circuit voltage value Va of the battery 1 before the start of cranking is measured, and the output voltage value Vb of the battery 1 during the cranking period 15 and the battery 1 are supplied. The internal resistance value Rin of the battery 1 is calculated by measuring the current value I and calculating Rin = (Va−Vb) / I based on the measurement results.

  On the other hand, the graphs of FIGS. 12 to 14 show the output voltage, the discharge current, and the internal resistance value during cranking in the same manner for the battery 1 in a state where the remaining charge level is less than the allowable level due to discharge. It shows the result of examining the transition of.

  Comparing the result of FIG. 11 with the result of FIG. 14, in the normal battery 1 in the fully charged state, the internal resistance value changes at a substantially constant level during the cranking period 15, but the battery 1 is overcharged. In the battery 1 whose remaining amount has decreased, it can be seen that the internal resistance value gradually increases during the cranking period 15.

  As a result of performing such a test on the battery 1 in various states, the internal resistance value tends to increase during the cranking period 15 in the battery 1 with insufficient charge remaining or the deteriorated battery 1. It was found that in the normal battery 1 having no problem, the internal resistance value is maintained at a constant level during the cranking period 15 and does not increase.

  Therefore, the applicant of the present application has determined that the inside of the battery 1 in a state where discharging for cranking is performed based on the output voltage of the battery 1 at the time of cranking the engine and the value of the current supplied from the battery 1. The resistance value is directly calculated, and it is determined whether or not the third condition is satisfied based on the change state (for example, the degree of increase) of the calculated internal resistance value during the cranking period 15. I thought. More specifically, if the internal resistance value tends to increase during the cranking period 15, it is determined that the third condition is not satisfied, and if the internal resistance value does not tend to increase, the third condition It turned out that it should be judged that the condition is satisfied.

  However, the detected value of the internal resistance of the battery 1 during the cranking period 15 fluctuates in a pulsating manner as shown in the graphs of FIGS. Therefore, for example, the following method can be considered for determining the trend of the internal resistance value within the period 15. As one method, as shown in FIG. 14, only the upper and lower peak values of the internal resistance value in the period 15 are compared in time series to obtain lines L06 and L07, and intermediate values between the lines L06 and L07 are obtained. It is possible to easily determine whether or not the internal resistance value in the cranking period 15 tends to increase based on the slope of the intermediate line and the like. As another method, a trend line for the internal resistance value waveform graph is obtained by the same method as the trend line L05 shown in FIG. 7A in the second detection method, and the trend line and the internal resistance value are obtained. A straight line is obtained from the point of intersection with the waveform graph by the least square method or the like, and it can be easily determined from the inclination whether the internal resistance value in the cranking period 15 tends to increase.

  Thus, in this embodiment, it is possible to easily determine whether or not the engine is started with respect to the output voltage of the battery 1 only by determining whether or not the first to third conditions are satisfied. Is possible. In particular, the viscosity of the lubricating oil generally used in the starter motor 5 and the engine is significantly affected by temperature, and various parameters are prepared due to other conditions such as vehicle type and individual differences. When complicated work is required, there is an advantage that it is possible to easily determine whether or not the engine is started simply by detecting the state (output voltage or the like) of the battery 1 realized in the cranking embodiment.

<2. Configuration>
FIG. 15 is a block diagram of a battery state detection device according to one embodiment of the present invention. As shown in FIG. 15, the battery state detection device includes a current sensor 21, a voltage sensor 23, a processing unit 25, a storage unit 27, and an output unit 29, and the state of the battery 1 mounted on the vehicle. Manage.

  The current sensor 21 has the above <1. The current output from battery 1 and the current input to battery 1 described in <Principle> are detected. The voltage sensor 23 has the above <1. The output voltage 13 of the battery 1 described in <Principle> is detected. The processing unit 25 includes a CPU (control unit) and the like, and performs various information processing operations (including control operations) for managing the battery 1. The storage unit 27 includes a rewritable nonvolatile memory such as a flash ROM. The output unit 29 is for outputting a determination result of the state of the battery 1, and for example, a display device such as a liquid crystal display panel, an audio output device, or the like is applied. In addition, when performing shut-off control or the like of various loads (for example, audio equipment) mounted on the vehicle according to the state of the battery 1, a load power supply control unit or the like is also applied as the output unit 29.

  Then, after the current detected by the current sensor 21 and the output voltage of the battery 1 detected by the voltage sensor 23 are converted into digital data by an A / D converter (not shown) mounted in the processing unit 25, Within the processing unit 25, the above <1. The first to third conditions described in <Principle> are determined, and whether or not the battery 1 is normal is output to the output unit 29. Further, a program that defines an operation procedure for the CPU of the processing unit 25 to operate, various data such as the above-described plunger drive minimum voltage Vc, engine ignitable rotation speed n01, and the predetermined formula shown in FIG. Information necessary for various information processing operations performed by the processing unit 25 is stored in the storage unit 27 in advance.

  Then, as illustrated in FIG. 16, the processing unit 25 includes a first condition determining unit 25a that determines the first condition, a second condition determining unit 25b that determines the second condition, and a third condition. The third condition determination unit 25c that makes the above determination and a comprehensive determination as to whether or not the state of the battery 1 is normal based on the determination results of the condition determination units 25a to 25c, and outputs the comprehensive determination result And a general determination unit 25d that outputs to the unit 29.

<3. Operation>
An operation example of the battery state detection device having the above configuration will be described with reference to the flowchart shown in FIG.

  First, when the ignition switch 6 is turned on, the output voltage of the battery 1 is detected by the voltage sensor 23, and the detection result is output to the processing unit 25.

  At this time, if the plunger 2 operates normally and cranking is performed normally, as shown in FIG. 5, the change in the cylinder pressure of each engine cylinder portion at the time of cranking (symbol # in FIG. 5) 1 to # 4), the output voltage of the battery 1 (FIG. 3) varies.

  Then, in step S01 in FIG. 17, the vibration that appears in the output voltage of the battery 1 when the CPU operates in accordance with the program stored in advance in the storage unit 27 in the second condition determination unit 25b of the processing unit 25. Attempts to detect the period or frequency of the waveform, and attempts to detect the cranking speed nr based on the detection result. The cranking speed nr is detected by the above <1. Since it is as described in (1-2. Second condition) in <Principle>, detailed description thereof is omitted here.

  If it is determined in step S02 that the cranking rotation speed nr has been detected in step S01, the process proceeds to step S03, and is stored in advance in the storage unit 27 in the third condition determination unit 25c of the processing unit 25. The cranking speed required in the crank period 15 (particularly, the cranking period 15 at the next engine start) whether or not the third condition is satisfied by the CPU operating according to the program being Whether or not can be maintained. Although this determination is omitted here in detail, <1. As explained in <Principle>, based on the output voltage of the battery 1 at the time of cranking the engine and the value of the current supplied from the battery 1, the battery 1 in a state where discharging for cranking is being performed is performed. This is done by directly calculating the internal resistance value and determining whether or not the calculated internal resistance value tends to increase during the cranking period 15 (data such as numerical conditions necessary for this determination) Is stored in advance in the storage unit 27).

  If it is determined in step S03 that the cranking rotation speed can be maintained, the process proceeds to step S04. If it is determined that the cranking rotation speed cannot be maintained, the process proceeds to step S06.

  On the other hand, if it is determined in step S02 that the cranking speed nr cannot be detected in step S01 (more specifically, the engine cranking has been performed, but the output level of the battery 1 is sufficiently high) Therefore, if the fluctuation of the output voltage due to cranking is small and the cranking rotation speed cannot be detected based on the output voltage), the process proceeds to step S05.

  In step S04, in the second condition determination unit 25b of the processing unit 25, the CPU operates according to a program stored in advance in the storage unit 27, for example, whether the second condition is satisfied, that is, The cranking speed nr detected in step S01 is compared with the engine ignition speed n01 stored in advance in the storage unit 27 to determine whether or not the engine can be ignited. If it is determined in step S04 that the cranking speed nr is equal to or greater than the engine ignition speed n01, the process proceeds to step S05, while the cranking speed nr is less than the engine ignition speed n01. If it is determined, the process proceeds to step S06.

  In step S05, in the first condition determination unit 25a of the processing unit 25, whether or not the first condition is satisfied by operating the CPU according to a program stored in advance in the storage unit 27, that is, FIG. 3, it is determined whether or not the lower limit voltage VL that appears at time T01 (when the power supply ignition switch 6 for the plunger 2 is turned on) is less than the plunger drive minimum voltage Vc. If it is determined in step S04 that the lower limit voltage VL is equal to or higher than the plunger drive minimum voltage Vc, the process proceeds to step S07. On the other hand, if it is determined that the lower limit voltage VL is lower than the plunger drive minimum voltage Vc, Proceed to S06.

  In step S07, information indicating that the battery 1 is in a normal state is output to the output unit 29 through the comprehensive determination unit 25d.

  Thereafter, the process proceeds to step S08, where the balance of the amount of charge of the battery 1 detected by the current sensor 21 is integrated by the processing unit 25, and predetermined processing such as full charge determination in step S09 is performed. In this case, when it is determined that the battery is fully charged, control for preventing overcharging is performed by stopping regeneration of the battery 1 or the like.

  In step S06, information indicating that the battery 1 needs attention is output to the output unit 29. The output unit 29 performs a caution display indicating that the battery 1 needs attention, a sound output for prompting attention, and the like. Further, when a load power supply control unit is included as the output unit 29, etc., the load power supply control unit is used to cut off various loads (for example, audio devices) mounted on the vehicle according to the state of the battery 1 or the like. I do.

  And it progresses to step S10, the balance of the charge amount of the battery 1 detected by the current sensor 21 is integrated | accumulated in the process part 25, and it progresses to step S11. In step S11, it is determined whether or not the charge balance exceeds a predetermined value Pc considering dark current for a predetermined number of days (for example, one week) of the automobile. Even if the dark current of the minute is taken into consideration, it is determined that the battery 1 is sufficiently charged, and the process proceeds to step S12. In step S12, information indicating that the battery 1 is in a normal state is output to the output unit 29 through the comprehensive determination unit 25d. Thereafter, the processing after step S10 is repeated.

  On the other hand, if it is determined in step S11 that the charge balance is equal to or less than the predetermined value Pc, the process proceeds to step S13, and it is first determined in step S14 whether or not the battery is fully charged.

  If it is determined in step S14 that the battery is not fully charged, the process returns to step S10 and the subsequent processing is repeated.

  On the other hand, if it is determined in step S14 that the battery is fully charged, the process proceeds to step S15, and it is determined again whether the charge balance exceeds the predetermined value Pc. When it is determined that the charge balance exceeds the predetermined value Pc, it is determined that the battery 1 is sufficiently charged even when the dark current for a predetermined number of days of neglect is taken into consideration. The process proceeds to step S16. In step S16, information indicating that the battery 1 is in a normal state is output to the output unit 29 through the general determination unit 25d. Thereafter, the processing after step S10 is repeated.

  On the other hand, if it is determined in step S15 that the charge balance is equal to or less than the predetermined value Pc, it is determined that the amount of charge until the battery 1 is fully charged is small, and it is determined that the battery 1 is at the end of its life. In step S17, information to that effect is output to the output unit 29. In this case, a warning display indicating that the battery 1 has reached the end of life, an audio output related to the warning, and the like are performed. Further, when a load power supply control unit is included as the output unit 29, etc., the load power supply control unit is used to cut off various loads (for example, audio devices) mounted on the vehicle according to the state of the battery 1 or the like. I do.

  As described above, the correlation between the actual internal resistance and the open circuit voltage of the battery deteriorates depending on the deterioration state. As a result, the correlation between the actual internal resistance and the amount of decrease in the battery output voltage at the start of the engine Even if it becomes worse, accurate state determination becomes difficult with the prior art in which state determination is performed using the output voltage drop directly.

  However, in this embodiment, the output voltage of the battery 1 is monitored, and based on the monitoring result, it is actually detected whether or not the first to third conditions are satisfied, and based on the detection result. Thus, it is determined whether or not the battery 1 is normal. Therefore, the characteristic curves G1 to G5 and the start limit line L01 of the battery 1 are uniformly determined in advance as in the method shown in FIG. There is no need. Accordingly, it is possible to accurately determine whether or not the battery is normal in response to the actual situation without taking into consideration various conditions such as the battery mounting environment such as the deterioration state and temperature and the vehicle model.

  Furthermore, by detecting the vibration of the output voltage 13 detected by the voltage sensor 23, the cranking speed can be easily and accurately detected without providing a dedicated mechanism for detecting the cranking speed. can do.

  Furthermore, the internal resistance value of the battery 1 is calculated based on the detection results of the voltage sensor 23 and the current sensor 21 at the time of engine cranking, and the change state (increasing tendency) of the calculated internal resistance value during the cranking period. Therefore, it is possible to easily and reliably evaluate the engine starting performance of the battery 1 because it is determined whether or not the battery 1 is normal.

  In the above embodiment, it is determined whether or not the lower limit voltage VL is equal to or higher than the plunger drive minimum voltage Vc in the first condition. However, whether or not the lower limit voltage VL is equal to or higher than the starter motor start minimum voltage. It can be judged. Here, the starter motor starting minimum voltage is not only the drive voltage of the plunger 2 necessary for the movable contact 3 of the plunger 2 to be connected to the fixed contact 4 but also the starter after the movable contact 3 of the plunger 2 is connected to the fixed contact 4. This also takes into account the drive voltage necessary for the motor 5 to rotate. When the starter motor 5 is driven, the viscosity of the lubricating oil is significantly affected by the temperature. Therefore, the starter motor starting minimum voltage that varies depending on the temperature environment may be stored in the storage unit 27 in advance.

  In the above-described embodiment, all of the first to third conditions are determined. However, if at least the third condition is included, any one or two of them are combined. You may make it judge.

It is a graph which shows the measurement result which measured the open circuit voltage and the lower limit voltage at the time of engine starting about the battery from which a deterioration condition and charge remaining amount differ. It is a schematic diagram which shows an example of a general starter. It is a figure which shows the change of the output voltage of a battery in the case of engine starting. It is a figure which shows the relationship between cranking rotation speed and an engine torque. It is a figure which shows a mode that the waveform of the voltage applied to a starter motor changes by cranking operation | movement. It is a figure which shows the principle which detects the period and trend change of the oscillation of an output voltage with a 1st detection method. It is a figure which shows the principle which detects the period and trend change of the oscillation of an output voltage with a 2nd detection method. It is a figure which shows the principle which detects the frequency of the oscillation of an output voltage with a 3rd detection method. It is a graph which shows the test result which measured the time-dependent characteristic of the output voltage at the time of engine cranking about the normal battery in a full charge state. It is a graph which shows the test result which measured the time-dependent characteristic of the discharge current at the time of engine cranking about the normal battery in a full charge state. It is a graph which shows the time-dependent characteristic of internal resistance at the time of cranking of the normal battery calculated based on the detection result of FIG.9 and FIG.10. It is a graph which shows the test result which measured the time-dependent characteristic of the output voltage at the time of engine cranking about the battery in which the charge remaining charge fell too much. It is a graph which shows the test result which measured the time-dependent characteristic of the discharge current at the time of engine cranking about the battery in which the charge remaining charge fell too much. It is a graph which shows the time-dependent characteristic of the internal resistance at the time of cranking of the battery in the excessive discharge state computed based on the detection result of FIG.12 and FIG.13. It is a block diagram which shows the battery state detection apparatus which concerns on one embodiment of this invention. It is a block diagram which shows the process part of the battery state detection apparatus which concerns on one embodiment of this invention. It is a flowchart which shows operation | movement of the battery state detection apparatus which concerns on one embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Battery 2 Plunger 5 Starter motor 6 Ignition switch 7 Gear 10 Engine cylinder part 13 Output voltage 15 Cranking period 21 Current sensor 23 Voltage sensor 25 Processing part 25a 1st condition judgment part 25b 2nd condition judgment part 25c 3rd Condition determination unit 25d Total determination unit 27 Storage unit 29 Output unit

Claims (2)

A battery state detection device for managing the state of a battery mounted on an automobile,
A voltage sensor for detecting the output voltage of the battery;
A current sensor for detecting a current supplied from the battery;
An internal resistance value of the battery is calculated based on detection results of the voltage sensor and the current sensor at the time of engine cranking, and the battery is considered in consideration of a change state of the calculated internal resistance value during a cranking period. A processing unit for detecting the state of
A battery state detection device comprising: The battery state detection device according to claim 1,
The processing unit detects a state of the battery in consideration of an increase degree of the internal resistance value of the battery during the cranking period.

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