JP2020078179A - Rechargeable battery state detection device and rechargeable battery state detection method - Google Patents

Abstract

To accurately estimate the state of a rechargeable battery regardless of the type of a rechargeable battery.SOLUTION: A rechargeable battery state detection device includes control means that supplies a control signal to a discharge circuit that discharges a rechargeable battery to pulse-discharge the rechargeable battery, receiving means that receives a voltage signal from a voltage sensor that detects a terminal voltage of the rechargeable battery and a current signal from a current sensor that detects a charge/discharge current of the rechargeable battery, detection means that detects a variation value between a voltage before the chargeable battery is pulse-discharged by the discharge circuit and a voltage of the chargeable battery during or after the discharge, determining means that determines whether the rechargeable battery is charged or discharged between a first time point and a second time point thereafter, estimation means that estimates the charge state of the rechargeable battery on the basis of a first variation value detected at the first time point, a second variation value detected at the second time point, and the determination result of the determination means, and output means that outputs the estimation result.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a rechargeable battery state detection device and a rechargeable battery state detection method.

  In Patent Document 1, a rechargeable battery is subjected to a plurality of pulse discharges in a rest period between charging steps and after different pulse discharges (for example, after a first pulse discharge and a second pulse discharge). There is disclosed a technique of comparing the voltages of 1 and controlling the charging condition when the difference exceeds a threshold value.

Japanese Patent Laid-Open No. 11-509078

  However, in the technique disclosed in Patent Document 1, since the voltage behavior after discharge varies depending on the size and type of rechargeable battery (normal liquid type, for idling stop vehicles, etc.) and manufacturer, a threshold value is set for each rechargeable battery. There is a need.

  This will be described more specifically. FIG. 27 shows the measurement results of the voltage (arrow) after the first pulse discharge and the voltage (arrow) after the fourth pulse discharge when the SOC of the rechargeable battery of size segment LN2 is 100% and 80%. In the rechargeable battery of size category LN2, the difference value after the pulse is 0.011V when the SOC shown by the solid curve is 100%, and the difference value after the pulse is 0.003V when the SOC shown by the broken line curve is 80%. Is.

  FIG. 28 shows the measurement results of the voltage (arrow) after the first pulse discharge and the voltage (arrow) after the fourth pulse discharge when the SOC of the rechargeable battery of size category LN5 is 100% and 80%. In the rechargeable battery of size category LN5, the difference value after the pulse is 0.006V when the SOC indicated by the solid curve is 100%, and the difference value after the pulse is 0.001V when the SOC indicated by the broken line curve is 80%. Is.

  Therefore, in order to distinguish between 80% and 100% of SOC, the threshold is set to 0.009V in the case of a rechargeable battery of size category LN2, and the threshold is set to a rechargeable battery of size category LN5. It must be set to 0.005V. That is, there is a problem that it is necessary to change the setting of the threshold according to the size of the rechargeable battery. Although not shown in FIGS. 27 and 28, it is necessary to change the threshold setting depending on the type and manufacturer of the rechargeable battery.

  The present invention has been made in view of the above circumstances, and is a rechargeable battery state detection device capable of accurately estimating the state of a rechargeable battery regardless of the size, type, etc. of the rechargeable battery. And it aims at providing the chargeable battery state detection method.

In order to solve the above problems, the present invention relates to a rechargeable battery state detection device for detecting a state of a rechargeable battery, wherein a control signal is supplied to a discharging circuit for discharging the rechargeable battery to supply the rechargeable battery. A pulse discharge control means, a voltage signal from a voltage sensor that detects the terminal voltage of the rechargeable battery, and a receiving means that receives a current signal from a current sensor that detects the charge / discharge current of the rechargeable battery, By referring to the voltage signal received by the receiving means, a variation value between the voltage before the dischargeable circuit is pulse-discharged by the discharge circuit and the voltage of the chargeable battery during or after discharging is detected. A detection unit, a determination unit that refers to the current signal received by the reception unit, and determines whether the rechargeable battery is charged or discharged between a first time point and a second time point thereafter; The rechargeable battery based on the first variation value detected by the detection means at the first time point, the second variation value detected by the detection means at the second time point, and the determination result of the determination means. And an output unit that outputs the estimation result of the estimation unit.
According to such a configuration, it is possible to accurately estimate the state of the rechargeable battery regardless of the size and type of the rechargeable battery.

In the present invention, the detection means detects a difference value between a voltage before pulse discharge by the discharge circuit and a voltage of the rechargeable battery during or after discharge, and the estimation means is the first A determination result of charge / discharge of the rechargeable battery between one time point and the second time point, and a first difference value and a second difference value detected by the detection means at the first time point and the second time point, respectively. The charging state of the rechargeable battery is estimated based on the above.
With such a configuration, it is possible to easily estimate the state of charge of the rechargeable battery using the difference value.

Further, in the present invention, the estimation means detects the detection means when the determination means determines that the rechargeable battery is charged between the first time point and the second time point. The detection is performed when the second difference value is smaller than the first difference value, or when the determination unit determines that the rechargeable battery is discharged between the first time point and the second time point. When the second difference value is larger than the first difference value detected by the means, it is determined that the rechargeable battery is in a state close to full charge.
With such a configuration, it is possible to reliably know whether or not the rechargeable battery is in a state close to full charge based on the difference value and the charge / discharge determination result.

In the present invention, the detection means detects an internal resistance value calculated based on a voltage and a current before the pulse discharge by the discharge circuit and a voltage and a current of the rechargeable battery during or after the discharge. The estimation means is configured to determine the charge / discharge determination result of the rechargeable battery between the first time point and the second time point, and the first internal detected by the detection means at the first time point and the second time point, respectively. The state of charge of the rechargeable battery is estimated based on the resistance value and the second internal resistance value.
With such a configuration, the state of charge of the rechargeable battery can be easily estimated based on the internal resistance value.

Further, in the present invention, the estimation means detects the detection means when the determination means determines that the rechargeable battery is charged between the first time point and the second time point. When the second internal resistance value is larger than the first internal resistance value, or when the determining unit determines that the rechargeable battery is discharged between the first time point and the second time point. When the second internal resistance value is smaller than the first internal resistance value detected by the detecting means, it is determined that the rechargeable battery is in a state close to full charge.
According to such a configuration, it is possible to reliably know whether or not the rechargeable battery is in a state close to full charge based on the internal resistance value and the charge / discharge determination result.

In the present invention, the control means causes the discharge circuit to execute pulse discharge a plurality of times,
It is characterized in that the detecting means detects a variation value between the voltage of the rechargeable battery before the discharging of a plurality of pulse discharges and during or after the discharging of the second and subsequent pulse discharges.
With such a configuration, it is possible to more accurately know the charge state of the rechargeable battery based on the detection results of a plurality of pulse discharges.

The present invention also provides a control step of supplying a control signal to a discharge circuit for discharging the rechargeable battery to pulse-discharge the rechargeable battery in the method for detecting the state of the rechargeable battery for detecting the state of the rechargeable battery. A voltage signal from a voltage sensor that detects the terminal voltage of the rechargeable battery, and a receiving step that receives a current signal from a current sensor that detects the charging / discharging current of the rechargeable battery; And a detection step of detecting a variation value between the voltage before the dischargeable circuit pulse-discharges the rechargeable battery by the discharge circuit and the voltage of the rechargeable battery during or after discharging, and the reception. A determination step of determining whether the rechargeable battery has been charged or discharged between a first time point and a second time point thereafter, by referring to the current signal received in the step; and the detection at the first time point. The state of charge of the rechargeable battery is estimated based on the first variation value detected in the step, the second variation value detected in the detection step at the second time point, and the determination result of the determination step. It is characterized by having an estimation step and an output step of outputting the estimation result of the estimation step.
According to such a method, the state of the rechargeable battery can be accurately estimated regardless of the size, type, etc. of the rechargeable battery.

  According to the present invention, it is possible to accurately estimate the state of a rechargeable battery regardless of the size, type, etc. of the rechargeable battery. It is possible to provide a rechargeable battery state detection device and a rechargeable battery state detection method. Becomes

It is a figure which shows the structural example of the chargeable battery state detection apparatus which concerns on 1st Embodiment of this invention. FIG. 2 is a block diagram showing a detailed configuration example of a control unit in FIG. 1. It is a figure which shows the time waveform of the electric current which flows through the discharge circuit shown in FIG. It is a figure which shows the time waveform of the voltage by the discharge circuit shown in FIG. FIG. 5 is a diagram showing a relationship between SOC and voltage change based on the measurement shown in FIG. 4. 6 is a flowchart for explaining an example of the operation of the first exemplary embodiment of the present invention. It is a figure for demonstrating the timing when the flowchart shown in FIG. 6 is performed. It is a figure for demonstrating operation | movement of 2nd Embodiment of this invention. FIG. 9 is a diagram showing a relationship between SOC and voltage change based on the measurement shown in FIG. 8. It is a figure for demonstrating operation | movement of 3rd Embodiment of this invention. It is a figure which shows the relationship between SOC and internal resistance based on the measurement shown in FIG. It is a figure for demonstrating operation | movement of 4th Embodiment of this invention. FIG. 13 is a diagram showing a relationship between SOC and voltage change based on the measurement shown in FIG. 12. It is a figure for demonstrating operation | movement of 5th Embodiment of this invention. It is a figure which shows the relationship between SOC and the voltage change based on the measurement shown in FIG. It is a figure for demonstrating operation | movement of 6th Embodiment of this invention. FIG. 17 is a diagram showing a relationship between SOC and internal resistance based on the measurement shown in FIG. 16. It is a figure for demonstrating the charging / discharging cycle at the time of actually measuring a chargeable battery. It is a figure which shows the waveform which measured the chargeable battery of size division LN2. It is a figure which shows the relationship between a state and a voltage change based on the actual measurement result shown in FIG. It is a figure which shows the waveform which measured the rechargeable battery of size division LN5. FIG. 22 is a diagram showing a relationship between a state and a voltage change based on the actual measurement result shown in FIG. 21. It is a figure which shows the waveform which actually measured the chargeable battery of battery type M-42. It is a figure which shows the relationship between a state and a voltage change based on the actual measurement result shown in FIG. It is a figure which shows the waveform which actually measured the chargeable battery of battery type M-42. It is a figure which shows the relationship between a state and internal resistance based on the actual measurement result shown in FIG. It is a figure which shows the measurement result of the chargeable battery of size division L2 by a prior art. It is a figure which shows the measurement result of the chargeable battery of size division L5 by a prior art.

  Next, an embodiment of the present invention will be described.

(A) Description of Configuration of First Embodiment of Present Invention FIG. 1 is a diagram showing a power supply system of a vehicle having a rechargeable battery state detection device according to a first embodiment of the present invention. In the figure, the rechargeable battery state detection device 1 has a control unit 10 as a main component, a voltage sensor 11, a current sensor 12, a temperature sensor 13, and a discharge circuit 15 are connected to the outside, and a rechargeable battery 14 is provided. Detect the state of. Note that the control unit 10, the voltage sensor 11, the current sensor 12, the temperature sensor 13, and the discharge circuit 15 may not have separate configurations, but may have a configuration in which some or all of them are integrated.

  Here, the control unit 10 refers to the outputs from the voltage sensor 11, the current sensor 12, and the temperature sensor 13, detects the state of the rechargeable battery 14, outputs the information of the detection result to the outside, and the alternator. The charge state of the rechargeable battery 14 is controlled by controlling the power generation voltage of 16. The voltage sensor 11 detects the terminal voltage of the rechargeable battery 14 and supplies it to the control unit 10 as a voltage signal. The current sensor 12 detects a current flowing through the rechargeable battery 14 and supplies it to the control unit 10 as a current signal. The temperature sensor 13 detects the temperature of the electrolytic solution of the rechargeable battery 14 or the ambient temperature of the rechargeable battery 14 and supplies it to the control unit 10 as a temperature signal. Note that the control unit 10 does not control the charging state of the rechargeable battery 14 by controlling the power generation voltage of the alternator 16, but, for example, an ECU (Electric Control Unit) (not shown) may control the charging state. Good.

  The rechargeable battery 14 is composed of a rechargeable battery having an electrolytic solution, for example, a lead storage battery, a nickel-cadmium battery, or a nickel-hydrogen battery, is charged by the alternator 16, and drives the starter motor 18 to start the engine. At the same time, electric power is supplied to the load 19. The rechargeable battery 14 is configured by connecting a plurality of cells in series.

  The discharge circuit 15 is composed of, for example, semiconductor switches and resistance elements connected in series, and turns on / off the semiconductor switches under the control of the control unit 10 to discharge the rechargeable battery 14 with a predetermined current. ..

  The alternator 16 is driven by the engine 17, generates AC power, converts the AC power into DC power by a rectifier circuit, and charges the rechargeable battery 14. The alternator 16 is controlled by the control unit 10 and is capable of adjusting the power generation voltage.

  The engine 17 includes, for example, a reciprocating engine such as a gasoline engine and a diesel engine, a rotary engine, or the like. The engine 17 is started by a starter motor 18, drives driving wheels via a transmission, and gives a propulsive force to the vehicle. To generate electric power. The starter motor 18 is composed of, for example, a DC electric motor, generates a rotational force by the electric power supplied from the rechargeable battery 14, and starts the engine 17.

  The load 19 is composed of, for example, an electric steering motor, a defogger, a seat heater, an ignition coil, a car audio system, a car navigation system, and the like, and is operated by electric power supplied from the rechargeable battery 14. In the example of FIG. 1, only the engine 17 outputs the driving force, but a hybrid vehicle including an electric motor that assists the engine 17 may be used. In the case of a hybrid vehicle, the rechargeable battery 14 activates a high-voltage system (system that drives an electric motor) composed of a lithium battery or the like, and the high-voltage system starts the engine 17.

  FIG. 2 is a diagram showing a detailed configuration example of the control unit 10 shown in FIG. As shown in the figure, the control unit 10 includes a CPU (Central Processing Unit) 10a, a ROM (Read Only Memory) 10b, a RAM (Random Access Memory) 10c, a communication unit 10d, an I / F (Interface) 10e, and It has a bus 10f. Here, the CPU 10a controls each unit based on the program 10ba stored in the ROM 10b. The ROM 10b is composed of a semiconductor memory or the like and stores the program 10ba or the like. The RAM 10c is configured by a semiconductor memory or the like, and stores data generated when the program 10ba is executed and data 10ca such as a table. The communication unit 10d communicates with an ECU (Electronic Control Unit), which is a higher-level device, and notifies the higher-level device of the detected information or control information. The I / F 10e converts the signals supplied from the voltage sensor 11, the current sensor 12, and the temperature sensor 13 into digital signals and takes them in, and also supplies a driving current to the discharge circuit 15, the alternator 16, the starter motor 18, and the like. Supply and control these. The bus 10f is a signal line group for connecting the CPU 10a, the ROM 10b, the RAM 10c, the communication unit 10d, and the I / F 10e to each other, and enabling the exchange of information among them.

  In the example of FIG. 2, one CPU 10a is provided, but the distributed processing may be executed by a plurality of CPUs. Further, instead of the CPU, a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), an ASIC (Application Specific Integrated Circuit), or the like may be used. Alternatively, the processing on the server computer may be performed by a general-purpose processor that executes a function by reading a software program or cloud computing. Further, although the ROM 10b and the RAM 10c are provided in FIG. 2, a storage device other than these (for example, an HDD (Hard Disk Drive) which is a magnetic storage device) may be used.

(B) Description of Operation of First Embodiment of Present Invention Next, an operation of the first embodiment of the present invention will be described. In the following, after the operation of the first embodiment of the present invention has been described, the processing of the flowchart for realizing such operation will be described.

  First, the outline of the operation of the first embodiment of the present invention will be described. When an ignition switch (not shown) is operated, the engine 17 of the vehicle is stopped, and a predetermined time (for example, several hours) elapses. For example, when polarization and stratification of the rechargeable battery 14 are eliminated, the control unit The CPU 10a of 10 refers to the voltage signal supplied from the voltage sensor 11 and measures the voltage V0 of the rechargeable battery 14.

  Next, the CPU 10a of the control unit 10 supplies a control signal to the discharge circuit 15 to pulse-discharge the rechargeable battery 14. FIG. 3 is a diagram for explaining a specific example of pulse discharge. The horizontal axis of FIG. 3 represents time (sec), and the vertical axis represents the discharge current (A) flowing from the rechargeable battery 14 to the discharge circuit 15. Further, in FIG. 3, the solid line shows the change in current when the SOC of the rechargeable battery 14 is 100%, the short broken line shows the change in current when the SOC is 80%, and the long broken line shows the SOC. Shows the change in current when 40%, and the alternate long and short dash line shows the change in current when SOC is 0%. As shown in FIG. 3, when the rectangular wave pulse discharge is started, the current (I0≈0A), which was about 0A before the discharge, becomes about 5A (I1≈5A). At this time, since the internal resistance varies depending on the SOC of the rechargeable battery 14, the discharge current also varies.

  The CPU 10a detects the voltage V1 of the rechargeable battery 14 by referring to the voltage signal supplied from the voltage sensor 11 after a lapse of a certain time from the end of the pulse discharge.

  FIG. 4 shows a temporal change in voltage when the rechargeable battery 14 is pulse-discharged. In FIG. 4, the horizontal axis represents time (sec) and the vertical axis represents voltage change (V) (for example, change from a predetermined reference voltage (for example, 12V)). Further, in FIG. 4, the solid line shows the change in voltage when the SOC of the rechargeable battery 14 is 100%, the broken line with a short interval shows the change in voltage when the SOC is 80%, and the broken line with a long interval shows the SOC. Shows the change in voltage when 40%, and the alternate long and short dash line shows the change in voltage when SOC is 0%. As shown in FIG. 4, when the SOC decreases from 80%, the voltage change increases correspondingly, but when the SOC reaches 100%, the voltage change does not decrease and increases.

  FIG. 5 is a diagram showing the relationship between the SOC and the difference value ΔV (= V1−V0) between the voltage V0 and the voltage V1 shown in FIG. In the example shown in FIG. 5, when the SOC increases up to 80%, the difference value ΔV also increases accordingly, but when the SOC exceeds 80%, the difference value ΔV starts to decrease.

  That is, the difference value ΔV between the voltage V0 before the pulse discharge and the voltage V1 after the pulse discharge increases in accordance with the increase in the SOC. However, when the SOC approaches the full charge, the difference changes from the increase to the decrease. As a result of the experiment, such a tendency was observed regardless of the size and type of the rechargeable battery 14 and the manufacturer.

  Therefore, in the first embodiment, the charge state of the rechargeable battery 14 is detected based on the above-described characteristics based on the difference value ΔV of the voltage before and after the pulse discharge and the charge state or the discharge state of the rechargeable battery 14. To do.

  Next, with reference to FIG. 6, an example of processing executed in the first embodiment shown in FIG. 1 will be described. When the process of the flowchart shown in FIG. 6 is started, the following steps are executed.

  In step S10, the CPU 10a of the control unit 10 determines whether or not the engine 17 is stopped. When it is determined that the engine 17 is stopped (step S10: Y), the process proceeds to step S11, and otherwise (step S10). The process ends at step S10: N). For example, the CPU 10a determines whether or not the ignition switch for stopping the engine 17 is operated by making an inquiry to an ECU (Electric Control Unit) (not shown) via the communication unit 10d, and the ignition switch is operated. When it is determined that the engine 17 is stopped, the process proceeds to step S11.

  In step S11, the CPU 10a determines whether or not a predetermined time (for example, several hours) has elapsed since the engine 17 was stopped, and when it is determined that the predetermined time has elapsed (step S11: Y). Proceeds to step S12, and otherwise (step S11: N), the same processing is repeated.

  In step S12, the CPU 10a refers to the voltage signal supplied from the voltage sensor 11 and measures the pre-discharge voltage V0 of the rechargeable battery 14.

  In step S13, the CPU 10a supplies a control signal to the discharging circuit 15 to pulse-discharge the rechargeable battery 14. Note that the pulse discharge may be, for example, a discharge having a rectangular waveform, a current value of about several amperes (for example, 1 A to 10 A), and a time width of several tens msec to several hundred msec. it can. Of course, waveforms or numerical values other than these may be set.

  In step S14, the CPU 10a determines whether or not a predetermined time (for example, several tens msec to several hundreds msec) has elapsed since the pulse discharge was executed, and when it is determined that the predetermined time has elapsed (step S14). If S14: Y), the process proceeds to step S15, and otherwise (step S15: N), the same process is repeated.

  In step S15, the CPU 10a refers to the voltage signal supplied from the voltage sensor 11 and measures the post-discharge voltage V1 of the rechargeable battery 14.

  In step S16, the CPU 10a calculates a difference value ΔV = V1-V0 between the pre-discharge voltage V0 measured in step S12 and the post-discharge voltage V1 measured in step S15. The difference value ΔV thus obtained is stored in the RAM 10c as data 10ca.

  In step S17, the CPU 10a determines whether or not the balance of charge and discharge from the previous measurement is positive, and when it is determined to be positive (step S17: Y), the process proceeds to step S18, and otherwise (step S17). The process ends at step S17: N). For example, as shown in FIG. 7, when the charge / discharge balance becomes positive in the next “charge / discharge stop” period from the “charge / discharge stop” period in which the process shown in FIG. 6 is executed, that is, If the rechargeable battery 14 has been charged (when the SOC has increased) from the previous "charging / discharging stop" period, it is determined to be Y and the process proceeds to step S18. As a method for calculating the charge / discharge balance, the balance can be calculated by the CPU 10a cumulatively adding the current signals supplied from the current sensor 12.

  In step S18, the CPU 10a acquires the difference value ΔV calculated in the previous “charge / discharge stop” period from the RAM 10c and substitutes it into ΔV0.

  In step S19, the CPU 10a causes the difference value ΔV calculated during the current “charge / discharge stop” period (first time point) and the difference value ΔV calculated during the previous “charge / discharge stop” period (second time point). ΔV0 is compared, and it is determined whether or not ΔV <ΔV0 is satisfied. If it is determined that ΔV <ΔV0 is satisfied, the process proceeds to step S20, and otherwise the process is terminated.

  In step S20, the CPU 10a determines that the rechargeable battery 14 is in a state close to full charge. More specifically, in step S17, when the rechargeable battery 14 is charged from the previous “charge / discharge stop” period to the current “charge / discharge stop” period, ΔV <ΔV0 When the condition is satisfied, it is determined that the rechargeable battery 14 exists in the negative region of the graph shown in FIG. The information indicating that the battery is almost fully charged is notified to the ECU (not shown) via the communication unit 10d, for example. The ECU that has received such a notification can reduce the output voltage of the alternator 16 to reduce the load on the engine 17 and improve fuel efficiency, for example.

  As described above, according to the first embodiment of the present invention, the voltage before and after the pulse discharge is measured, and the state of the rechargeable battery 14 is detected based on the increase / decrease of these difference values. The state can be detected regardless of the size, type, and manufacturer of the rechargeable battery 14.

(C) Description of Configuration of Second Embodiment of Present Invention Next, a configuration example of the second embodiment of the present invention will be described. The configuration example of the second embodiment is the same as that of the first embodiment shown in FIGS. 1 and 2, but the process executed by the control unit 10 is different.

(D) Description of Operation of Second Embodiment of Present Invention Next, an operation of the second embodiment of the present invention will be described. In the first embodiment, as shown in FIG. 4, the voltage V0 before the start of pulse discharge and the voltage V1 after the end are measured, and the state of the rechargeable battery 14 is detected based on the difference value ΔV between them. However, in the second embodiment, as shown in FIG. 8, the state of the rechargeable battery 14 is detected based on the difference value ΔV between the voltage V0 before the start of discharge and the voltage V1p before the end of discharge. The timing of measuring the voltage V1p before the end of discharge can be, for example, a timing within about 20% before the end of pulse discharge. Of course, timings other than this (for example, within about 50 to 30%) may be set.

  FIG. 9 is a diagram showing a change in SOC of a difference value ΔV between the voltage V0 before the start of discharge and the voltage V1p before the end of discharge. The horizontal axis of FIG. 9 represents SOC, and the vertical axis represents the difference value ΔV. As shown in FIG. 9, the difference value ΔV increases as the SOC increases when the SOC is less than 80%, but starts to decrease when the SOC exceeds 80%. Therefore, when the difference value ΔV turns from increasing to decreasing in the SOC increasing state of the rechargeable battery 14, it is possible to determine that the rechargeable battery 14 is in a state close to full charge.

  As described above, according to the second embodiment of the present invention, the rechargeable battery is measured based on the increase / decrease in the difference value between the voltages before and after pulse discharge and the charge / discharge balance. Since the state of the rechargeable battery 14 is detected, the state can be detected regardless of the size, type, and manufacturer of the rechargeable battery 14.

(E) Description of Configuration of Third Embodiment of the Present Invention Next, the configuration of the third embodiment of the present invention will be described. The configuration of the third embodiment is the same as that of the first embodiment shown in FIGS. 1 and 2, but the processing executed by the control unit 10 is different.

(F) Description of Operation of Third Embodiment of Present Invention Next, an operation of the third embodiment of the present invention will be described. In the first and second embodiments, the voltage V0 before pulse discharge and the voltages V1p and V1 during or after pulse discharge are measured, and the state of the rechargeable battery 14 is detected based on the difference value ΔV between them. However, in the third embodiment, the internal resistance R is obtained from the voltage difference value ΔV and the current difference value ΔI, and the state of the rechargeable battery 14 is detected based on the internal resistance R.

  More specifically, when the voltage and current before the start of pulse discharge are V0 and I0 and the voltage and current before the end of pulse discharge are V1p and I1p, the internal resistance R = (V1p-V0) / (I1p-I0). It is defined as.

  FIG. 10 is a diagram showing a relationship between the internal resistance R obtained as described above and time. More specifically, the horizontal axis of FIG. 10 represents time (sec), and the vertical axis represents internal resistance (mΩ). Further, in FIG. 10, a solid line shows a change in internal resistance when the SOC of the rechargeable battery 14 is 100%, a short broken line shows a change in internal resistance when the SOC is 80%, and a long broken line. Indicates the change in internal resistance when the SOC is 40%, and the alternate long and short dash line indicates the change in internal resistance when the SOC is 0%.

  FIG. 11 is a diagram showing the relationship between SOC and changes in internal resistance. More specifically, the horizontal axis of FIG. 11 represents SOC (%), and the vertical axis represents internal resistance change (mΩ). As shown in FIG. 11, when the SOC is less than 80%, the internal resistance R decreases as the SOC increases, and when the SOC exceeds 80%, the internal resistance R starts to increase. Therefore, for example, when the charge / discharge balance of the rechargeable battery 14 is positive and the change in the internal resistance R changes from decreasing to increasing, the SOC shown in FIG. 11 belongs to a region exceeding 80%. It can be determined that there is a full charge, and it can be determined that the state is close to full charge.

  As described above, according to the third embodiment of the present invention, the internal resistance is calculated from the voltage and current before the pulse discharge and during or after the pulse discharge, and the increase and decrease of the internal resistance and the balance of charge and discharge are calculated. Since the state of the rechargeable battery 14 is detected based on the above, the state can be detected regardless of the size, type, and manufacturer of the rechargeable battery 14.

(G) Description of Configuration of Fourth Embodiment of the Present Invention Next, the configuration of the fourth embodiment of the present invention will be described. The configuration of the fourth embodiment is the same as that of the first embodiment shown in FIGS. 1 and 2, but the processing executed by the control unit 10 is different.

(H) Description of Operation of Fourth Embodiment of Present Invention Next, an operation of the fourth embodiment of the present invention will be described. In the first and second embodiments, one pulse discharge is executed, the voltage V0 before the pulse discharge and the voltage V1 during or after the pulse discharge are measured, and the rechargeable battery is based on the difference value ΔV between them. However, in the fourth embodiment, as shown in FIG. 12, pulse discharge is performed a plurality of times (five times in FIG. 12), and the voltage V0 before the pulse discharge is performed a plurality of times. Then, the difference values ΔV1 to ΔV5 of the voltages V1 to V5 after a lapse of a predetermined time from the end of each pulse discharge are obtained, and the state of the rechargeable battery 14 is detected based on the change of these difference values ΔV1 to ΔV5. The pulse discharge cycle can be set to, for example, 1/2 sec. Of course, a cycle other than this (for example, 1 to 1/100 sec) may be set. Although the number of times of pulse discharge is set to 5 in FIG. 12, it can be set to any number of times of 2 or more as long as the SOC of the rechargeable battery 14 does not decrease due to discharge.

  FIG. 13 is a diagram showing the relationship between the SOC and the difference value ΔV when the pulse discharge is performed a plurality of times. The horizontal axis of FIG. 13 represents SOC (%), and the vertical axis represents the difference value ΔV (V). Further, the solid broken line shows the change due to the SOC of ΔV1 = V1-V0, the broken line with a short interval shows the change due to the SOC of ΔV2 = V2-V0, and the broken line with a long interval shows the change of ΔV3 = V3-V0. The change due to SOC, the broken line of the one-dot chain line shows the change due to the SOC of ΔV4 = V4-V0, and the broken line of the two-dot chain line shows the change due to the SOC of ΔV5 = V5-V0. As shown in FIG. 13, when the pulse discharge is performed a plurality of times, the slope of the polygonal line becomes larger as the number of pulse discharges becomes larger, so that the state of the rechargeable battery 14 can be easily detected.

  As described above, according to the fourth embodiment of the present invention, the pulse discharge is executed a plurality of times, the difference value is calculated from the voltage before the pulse discharge and the voltage after the discharge of each pulse discharge, and the difference value is calculated. Since the state of the rechargeable battery 14 is detected based on the increase / decrease and the balance of charge / discharge, the state can be detected regardless of the size, type, and manufacturer of the rechargeable battery 14.

(I) Description of Configuration of Fifth Embodiment of the Present Invention Next, the configuration of the fifth embodiment of the present invention will be described. The configuration of the fifth embodiment is the same as that of the first embodiment shown in FIGS. 1 and 2, but the process executed by the control unit 10 is different.

(J) Description of Operation of Fifth Embodiment of the Present Invention Next, an operation of the fifth embodiment of the present invention will be described. In the fourth embodiment, pulse discharge is performed a plurality of times, and the state of the rechargeable battery 14 is detected based on the difference values ΔV1 to ΔV5 between the voltage V0 before pulse discharge and the voltages V1 to V5 after pulse discharge. However, in the fifth embodiment, as shown in FIG. 14, pulse discharge is performed a plurality of times (five times in FIG. 14), and the voltage V0 before the pulse discharge is performed a plurality of times and during each pulse discharge. The difference values ΔV1 to ΔV5 of the voltages V1p to V5p are calculated, and the state of the rechargeable battery 14 is detected based on the changes in these difference values ΔV1 to ΔV5. The cycle of pulse discharge can be set to, for example, 1/2 sec, as in the above-described fourth embodiment. Of course, a cycle other than this (for example, 1 to 1/100 sec) may be set. In addition, although the number of pulse discharges is 5 in FIG. 14, it can be set to any number of 2 or more as long as the SOC of the rechargeable battery 14 does not decrease due to discharge.

  FIG. 15 is a diagram showing the relationship between the SOC and the difference value ΔV when the pulse discharge is performed a plurality of times. The horizontal axis of FIG. 15 represents SOC (%), and the vertical axis represents the difference value ΔV (V). Further, the solid broken line shows the change due to the SOC of ΔV1 = V1-V0, the broken line with a short interval shows the change due to the SOC of ΔV2 = V2-V0, and the broken line with a long interval shows the change of ΔV3 = V3-V0. The change due to SOC, the broken line of the one-dot chain line shows the change due to the SOC of ΔV4 = V4-V0, and the broken line of the two-dot chain line shows the change due to the SOC of ΔV5 = V5-V0. As shown in FIG. 15, when the pulse discharge is performed a plurality of times, the slope of the polygonal line becomes larger as the number of pulse discharges is larger, so that the state of the rechargeable battery 14 can be easily detected.

  As described above, according to the fifth embodiment of the present invention, the pulse discharge is performed a plurality of times, the difference value is calculated from the voltage before the pulse discharge and the voltage during each pulse discharge, and the difference value is increased or decreased. Since the state of the rechargeable battery 14 is detected based on the charge / discharge balance, the state can be detected regardless of the size, type, and manufacturer of the rechargeable battery 14.

(K) Description of Configuration of Sixth Embodiment of Present Invention Next, the configuration of the sixth embodiment of the present invention will be described. The configuration of the sixth embodiment is the same as that of the first embodiment shown in FIGS. 1 and 2, but the processing executed by the control unit 10 is different.

(L) Description of Operation of Sixth Embodiment of Present Invention Next, an operation of the sixth embodiment of the present invention will be described. In the fifth embodiment, the pulse discharge is performed a plurality of times, and the state of the rechargeable battery 14 is detected based on the difference value between the voltage V0 before the pulse discharge and the voltages V1 to V5 during the discharge. In the sixth embodiment, as shown in FIG. 16, pulse discharge is performed a plurality of times (five times in FIG. 16), voltage V0 and current I0 before pulse discharge, and voltages V1 to V5 and current values during pulse discharge. The internal resistances R1 to R5 are detected based on I1 to I5, and the state of the rechargeable battery 14 is detected based on these internal resistances R1 to R5. The cycle of pulse discharge can be set to, for example, 1/2 sec, as in the above-described fourth embodiment. Of course, a cycle other than this (for example, 1 to 1/100 sec) may be set. In addition, although the number of times of pulse discharge is set to 5 in FIG. 16, it can be set to any number of times of 2 or more as long as the SOC of the rechargeable battery 14 does not decrease due to discharge.

  FIG. 17 is a diagram showing the relationship between the internal resistances R1 to R5 and SOC when a plurality of pulse discharges are performed. The horizontal axis of FIG. 17 represents SOC (%), and the vertical axis represents internal resistance (mΩ). The solid polygonal line shows the change due to the SOC of R1 = (V1-V0) / (I1-I0), and the broken line with a short interval shows the change due to the SOC of R2 = (V2-V0) / (I2-I0). The broken line with a long interval shows a change due to SOC of R3 = (V3-V0) / (I3-I0), and the broken line of the one-dot chain line shows R4 = (V4-V0) / (I4-I0). The change due to SOC is shown, and the broken line of the two-dot chain line shows the change due to SOC of R5 = (V5-V0) / (I5-I0). As shown in FIG. 17, when the pulse discharge is performed a plurality of times, the slope of the polygonal line becomes larger as the number of times of the pulse discharge is larger, so that the state of the rechargeable battery 14 can be easily detected.

  As described above, according to the sixth embodiment of the present invention, the pulse discharge is performed plural times, the internal resistance is calculated from the voltage and the current before the pulse discharge and during each pulse discharge, and the internal resistance is calculated. Since the state of the rechargeable battery 14 is detected based on the increase / decrease, the state can be detected regardless of the size, type, and manufacturer of the rechargeable battery 14.

(M) Measurement Result Next, the measurement result according to each embodiment of the present invention will be described. As shown in FIG. 18, during the charging stop period (the period when the ignition switch is operated and the engine 17 is stopped), the target rechargeable battery 14 is pulse-discharged to detect the state of the rechargeable battery 14. I shall. Note that the states of the rechargeable battery 14 in the respective charge stop periods are states A to C, state A is SOC = 40%, state B is SOC = 80%, and state C is SOC = 100. % State.

  FIG. 19 shows the result of actual measurement of the rechargeable battery 14 of the EN (European Norm) standard size division LN2 in the charge / discharge cycle as shown in FIG. The horizontal axis of FIG. 19 represents time (sec), and the vertical axis represents voltage change (V). Further, in FIG. 19, the solid line curve shows the voltage change due to the pulse discharge in the state A, the short broken line curve shows the voltage change due to the pulse discharge in the state B, and the long interval broken line curve shows the pulse in the state C. The change in voltage due to discharge is shown.

  FIG. 20 is a diagram showing the relationship between the state of rechargeable battery 14 shown in FIG. 19 and voltages V1-V0. As shown in FIG. 20, the rechargeable battery 14 of the EN standard size section LN2 is V1-V0 (= ΔV) when the state A (SOC = 40%) changes to the state B (SOC = 80%). However, V1-V0 decreases when the state B shifts to the state C (SOC = 100%). Therefore, when the balance of charge and discharge is positive (charge amount> discharge amount) in the charge and discharge section shown in FIG. 18 and the voltage V1-V0 is negative, the rechargeable battery 14 is close to full charge. It can be determined that the state (state of 80% <SOC ≦ 100%).

  Next, FIG. 21 shows the result of actual measurement of the rechargeable battery 14 of the EN standard size division LN5 in the charge / discharge cycle as shown in FIG. The horizontal axis of FIG. 21 represents time (sec), and the vertical axis represents voltage change (V). Further, in FIG. 21, the solid line curve shows the voltage change due to the pulse discharge in the state A, the short broken line curve shows the voltage change due to the pulse discharge in the state B, and the long broken line curve shows the pulse in the state C. The change in voltage due to discharge is shown.

  FIG. 22 is a diagram showing the relationship between the state of the rechargeable battery 14 shown in FIG. 21 and the voltage V1−V0 (= ΔV). As shown in FIG. 22, in the rechargeable battery 14 of the EN standard size division LN5, V1-V0 increases when the state A (SOC = 40%) shifts to the state B (SOC = 80%). , V1-V0 decreases when the state B shifts to the state C (SOC = 100%). Therefore, when the balance of charge and discharge is positive (charge amount> discharge amount) in the charge and discharge section shown in FIG. 18 and the voltage V1-V0 is negative, the rechargeable battery 14 is close to full charge. It can be determined that the state (state of 80% <SOC ≦ 100%).

  Next, FIG. 23 is a result of actual measurement of a rechargeable battery 14 (degradable rechargeable battery for idling stop) of a battery type M-42 of JIS (Japanese Industrial Standard) standard in a charge / discharge cycle as shown in FIG. Is shown. In FIG. 23, the horizontal axis represents time (sec) and the vertical axis represents voltage change (V). In FIG. 23, the solid curve represents the voltage change due to the pulse discharge in the state A, the short dashed curve represents the voltage change due to the pulse discharge in the state B, and the long broken curve represents the pulse in the state C. The change in voltage due to discharge is shown.

  FIG. 24 is a diagram showing the relationship between the state of rechargeable battery 14 shown in FIG. 23 and voltages V1-V0. As shown in FIG. 24, in the rechargeable battery 14 of the JIS standard battery type M-42, V1-V0 increases when the state A (SOC = 40%) is changed to the state B (SOC = 80%). However, when transitioning from the state B to the state C (SOC = 100%), V1-V0 decreases. Therefore, when the balance of charge and discharge is positive (charge amount> discharge amount) in the charge and discharge section shown in FIG. 18 and the voltage V1-V0 is negative, the rechargeable battery 14 is close to full charge. It can be determined that the state (state of 80% <SOC ≦ 100%).

  Next, FIG. 25 shows a result of actually measuring the internal resistance of the rechargeable battery 14 of the JIS standard battery type M-42 (a rechargeable battery that has deteriorated for idling stop) in a charge / discharge cycle as shown in FIG. ing. The horizontal axis of FIG. 25 represents time (sec), and the vertical axis represents internal resistance (mΩ). In addition, in FIG. 25, the solid curve represents the change in internal resistance due to pulse discharge in state A, the short-dashed curve represents the change in internal resistance due to pulse discharge in state B, and the long-dashed curve represents The change in internal resistance due to pulse discharge in state C is shown.

  FIG. 26 is a diagram showing the relationship between the state of the rechargeable battery 14 shown in FIG. 25 and the internal resistance. As shown in FIG. 26, in the rechargeable battery 14 of the JIS standard battery type M-42, the internal resistance decreases when shifting from the state A (SOC = 40%) to the state B (SOC = 80%). However, the internal resistance increases when shifting from the state B to the state C (SOC = 100%). Therefore, when the charge / discharge balance is positive (charge amount> discharge amount) in the charge / discharge section shown in FIG. 18 and the internal resistance increases, the rechargeable battery 14 is in a state close to full charge (80 % <SOC ≦ 100%).

(C) Description of Modified Embodiments It goes without saying that the above embodiment is an example and the present invention is not limited to the above-described case. For example, in each of the above embodiments, the state of charge of the rechargeable battery 14 is determined based on the difference value ΔV between the voltage V0 before the pulse discharge and the voltage V1 during the pulse discharge or after the pulse discharge. Instead of the difference value, for example, the ratio of the voltages V0 and V1 (for example, V1 / V0) may be used. That is, the “variation value” in the claims includes not only the difference value but also the ratio.

  In each of the above embodiments, the charge state is determined by the difference value ΔV when the charge / discharge balance is positive or the increase / decrease in the internal resistance R, but the difference when the charge / discharge balance is negative. The state of charge may be determined by increasing or decreasing the value ΔV or the internal resistance R. More specifically, for example, in FIG. 5, when the charge / discharge balance is negative (when SOC decreases), when the difference value ΔV increases, it is determined that 80 <SOC ≦ 100 exists. can do. The same applies to the other embodiments.

  Further, in each of the above embodiments, the temperature of the rechargeable battery 14 is not taken into consideration. However, since the voltage of the rechargeable battery 14 changes depending on the temperature, the measured voltage or the internal resistance is set to the reference temperature (for example, It is also possible to correct the voltage or internal resistance at 25 ° C.) and determine the state based on the corrected voltage or internal resistance. As a method of correcting to the reference temperature, a relational expression or table showing the relation between temperature and voltage or internal resistance can be stored as data 10ca in the RAM 10c, and correction can be performed based on the relational expression or table.

  Further, the flowchart shown in FIG. 6 is an example, and the present invention is not limited to only the processes of these flowcharts.

1 Rechargeable Battery State Detection Device 10 Control Unit 10a CPU
10b ROM
10c RAM
10d communication unit 10e I / F
11 Voltage Sensor 12 Current Sensor 13 Temperature Sensor 14 Rechargeable Battery 15 Discharge Circuit 16 Alternator 17 Engine 18 Starter Motor 19 Load

Claims (7)

In the rechargeable battery state detection device for detecting the state of the rechargeable battery,
Control means for supplying a control signal to a discharge circuit for discharging the rechargeable battery to pulse discharge the rechargeable battery,
Receiving means for receiving a voltage signal from a voltage sensor that detects the terminal voltage of the rechargeable battery and a current signal from a current sensor that detects the charge / discharge current of the rechargeable battery,
With reference to the voltage signal received by the receiving means, a variation value between a voltage before the discharge circuit is pulse-discharged by the discharge circuit and a voltage value of the chargeable battery during or after discharging is detected. Detection means,
Determining means for determining whether the rechargeable battery is charged or discharged between a first time point and a second time point thereafter, by referring to the current signal received by the receiving means;
The charging is possible based on the first variation value detected by the detection means at the first time point, the second variation value detected by the detection means at the second time point, and the determination result of the determination means. Estimating means for estimating the state of charge of the battery,
Output means for outputting the estimation result of the estimation means,
A rechargeable battery state detecting device comprising: The detecting means detects a difference value between a voltage before pulse discharging by the discharging circuit and a voltage of the rechargeable battery during discharging or after discharging,
The estimation means determines a charge / discharge determination result of the rechargeable battery between the first time point and the second time point, and a first difference value detected by the detection means at the first time point and the second time point. And estimating the state of charge of the rechargeable battery based on the second difference value,
The rechargeable battery state detection device according to claim 1, wherein:   The estimating means is more than the first difference value detected by the detecting means when the determining means determines that the rechargeable battery is charged between the first time point and the second time point. When the second difference value is small, or when the determination unit determines that the rechargeable battery is discharged between the first time point and the second time point, the detection unit detects the rechargeable battery. The rechargeable battery state detection device according to claim 2, wherein when the second difference value is larger than the first difference value, it is determined that the rechargeable battery is in a state close to full charge. The detection means detects the voltage and current before pulse discharge by the discharge circuit, and the internal resistance value calculated based on the voltage and current of the rechargeable battery during or after discharge,
The estimation means is configured to determine the charge / discharge determination result of the rechargeable battery between the first time point and the second time point, and the first internal resistance detected by the detection means at the first time point and the second time point. Estimating the state of charge of the rechargeable battery based on the value and the second internal resistance value,
The rechargeable battery state detection device according to claim 1, wherein:   The estimating means uses the first internal resistance value detected by the detecting means when the determining means determines that the rechargeable battery is charged between the first time point and the second time point. Is detected by the detection means when the second internal resistance value is large or when the determination means determines that the rechargeable battery is discharged between the first time point and the second time point. The rechargeable battery state according to claim 4, wherein when the second inner resistance value is smaller than the first inner resistance value, it is determined that the rechargeable battery is in a state close to full charge. Detection device. The control means causes the discharge circuit to execute pulse discharge a plurality of times,
The detecting means detects a variation value between the voltage of the rechargeable battery before discharging a plurality of pulse discharges and during or after discharging the pulse discharges after a second time,
The rechargeable battery state detection device according to any one of claims 1 to 5, characterized in that. In the rechargeable battery state detection method for detecting the state of the rechargeable battery,
A control step of supplying a control signal to a discharge circuit for discharging the rechargeable battery to pulse discharge the rechargeable battery;
A receiving step of receiving a voltage signal from a voltage sensor for detecting a terminal voltage of the rechargeable battery and a current signal from a current sensor for detecting a charge / discharge current of the rechargeable battery;
With reference to the voltage signal received in the receiving step, a variation value between a voltage before the dischargeable circuit is pulse-discharged by the discharge circuit and a voltage of the chargeable battery during or after discharging is detected. A detection step,
A determination step of determining whether the rechargeable battery is charged or discharged between a first time point and a second time point thereafter, by referring to the current signal received in the receiving step;
The charging is possible based on the first variation value detected in the detection step at the first time point, the second variation value detected in the detection step at the second time point, and the determination result of the determination step. An estimation step of estimating the state of charge of the battery,
An output step of outputting the estimation result of the estimation step,
A method for detecting a state of a rechargeable battery, comprising:

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