JPH06242192A - Judging device for life of battery - Google Patents

Abstract

PURPOSE:To provide a battery life judging device which can judge the life of a battery without influence caused by service conditions such as load electric power and ambient temperature and the state of the battery. CONSTITUTION:A sensor 10 composed of sensor sections which measure ambient temperature, terminal voltage and output current is provided near a battery 5, and measurement data detected by each sensor section are sent to a processing section 11, and a judging time for judging the life of the battery on fuzzy reasoning and voltage drop rate to be a criterion value after the judging time are obtained in a judging voltage-time deciding section 11a and set up in a life judging section 11b, which issues a fixed false service interruption signal to a change-over switch 2 to cause initial discharge for activating the battery, and then makes the battery electric capacity recover and discharge again. The time when the terminal voltage drop rate of the battery in the course of the true discharge attains, a criterion voltage drop rate is detected by a timer in the judging section, anal the above time is compared with the judging time to judge the propriety of the life of the battery, and the result of judgement is output to a display section 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery life judging device, and more particularly to a device for judging the life of a secondary battery incorporated in an uninterruptible power supply or the like.

[0002]

2. Description of the Related Art Conventionally, in an apparatus including a backup battery such as an uninterruptible power supply (UPS), in order to know the replacement time of the built-in battery (for example, lead acid battery),
For example, a life determining device as disclosed in Japanese Patent Laid-Open No. 2-55536 is used to determine the life of a built-in battery. That is, the life determination device of this type first charges the battery by a method such as floating charging during normal times (when power is being supplied from the commercial power source to the load). Then, a pseudo power failure is generated and power is supplied from the battery to the load. Measure the terminal voltage of the battery during discharge, find the integrated amount of the output current until the voltage drops to a predetermined voltage, and determine if the integrated amount has reached the predetermined amount to determine whether the battery has reached the end of life. I try to make a decision.

[0003]

However, the above life determining device has various problems as described below. That is, when a battery is discharged in a pseudo power failure to determine the life from the inactive state of the battery such as a floating charge state, the terminal voltage of the battery may temporarily drop after the discharge starts. . The occurrence and the degree of occurrence of such a phenomenon depend on the state of the battery and are not always constant. Therefore, if the determination is made based on the integral amount as described above, it is not possible to make an accurate (uniform) life determination due to variations in initial conditions.

Further, in the conventional device, whether or not the battery has reached the end of its life is uniquely determined by a predetermined threshold value. However, the discharge characteristic of the battery varies depending on the load power supplied and the temperature. Moreover, since the discharge characteristics are affected by the size of the battery and the usage period and history of the battery accompanying changes in the state of the electrodes, accurate determination cannot be performed.
In other words, since the discharge characteristics change depending on the usage conditions as described above, it is not possible to obtain a relational expression between the terminal voltage and the discharge power amount (integrated value of current) that can be applied to all usage conditions. In the above device that actually discharges an actual load having a different load power depending on the usage state, the dischargeable capacity varies each time, and it is not possible to accurately determine the discharge power amount that is the criterion for determination.

On the other hand, in order to solve the above problem, it is possible to provide a pseudo load such as a resistor in which the load current is always constant, and to supply a current to the pseudo load during a pseudo power failure. However, in such a case, the pseudo load for life determination, a switch for enabling power supply by the pseudo load, and means for suppressing heat generation during energization of the pseudo load are required. Large size
Not only is it complicated, but its control becomes complicated. Moreover, a new problem arises in that a part of the energy stored in the battery is unnecessarily consumed by the pseudo load.

The present invention has been made in view of the above background, and an object of the present invention is not to require a special device (pseudo load or the like) for life determination, and moreover, to supply electric power from a battery to an actual load. It is an object of the present invention to provide a battery life determining device capable of performing life determination while being supplied, without being affected by use conditions such as electric power of the actual load and ambient temperature and the state of the battery.

[0007]

In order to achieve the above-mentioned object, in the battery life determining apparatus according to the present invention, means for causing a pseudo power failure to supply power from the battery to the load,
Means for measuring the characteristic amount of the discharge characteristic of the battery during the pseudo power failure, and means for determining the life of the battery based on the measured characteristic value of the battery, the pseudo power failure for the activation of the battery The pseudo power failure and the pseudo power failure after the power restoration are performed twice, and the life judgment is performed during the second pseudo power failure.

Further, a means for confirming that the battery is fully charged, a means for causing a pseudo power failure to supply power from the battery to the load, and a characteristic amount of the discharge characteristic of the battery during the pseudo power failure are measured. Means and means for determining the life of the battery based on the measured characteristic amount of the battery may be provided, and the life may be determined only when the battery is fully charged.

Further, means for measuring the ambient temperature and electric power of the battery, means for obtaining a life criterion based on the ambient temperature and electric power, means for causing a pseudo power failure to supply electric power from the battery to the load, and A means for measuring the characteristic amount of the discharge characteristic of the battery during a power failure, a characteristic amount measured by the means for measuring the characteristic amount, and a means for judging the life based on the life judging criterion good.

Further, it is more preferable that the above-mentioned respective devices are appropriately combined and configured. Further, a plurality of judgment criteria are provided so that the degree of deterioration of the battery can be judged.
Further, it is more preferable to provide a means for detecting a load change, monitor the presence or absence of the load change during the life determination, and terminate the determination process when the change occurs.

[0011]

When the life is judged when the load is supplied with power from the commercial power source or the like, first, it is confirmed that the battery is fully charged, and then a pseudo power failure is generated to supply the power from the battery to the load. At this time, if the battery is inactive, there is a risk of a temporary decrease in the output voltage, so the pseudo power failure is terminated after a short time discharge. After that, a pseudo power failure is performed again and the main discharge from the battery to the load is performed. As a result, the battery is activated when the main discharge is performed, and the initial conditions are equal regardless of the state of the battery. Then, the characteristic amount indicating the discharge characteristic of the battery during the main discharge is measured, and it is compared with a predetermined determination criterion to determine whether or not the battery is at the end of life. Also,
As the above-mentioned judgment standard, an appropriate standard according to the usage situation is set by obtaining the ambient temperature measured during discharge from the battery during the pseudo power failure, fuzzy inference from the electric power, and the like.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of a battery life determining device according to the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 shows an example in which an embodiment of a life determining device according to the present invention is mounted on a UPS. As shown in the figure, the output of the commercial power supply 1 is connected in parallel to the changeover switch 2 and the charger 3, and the output of the commercial power supply 1 is directly supplied to the load 4 via the changeover switch 2 during normal operation. On the other hand, the charger 3 is adapted to perform floating charging on the battery 5 while converting the alternating current output from the commercial power source 1 into direct current. As a result, even if the battery 5 is naturally discharged, it is always charged with a weak current, and the battery 5 is in principle always in a fully charged state. The battery 5 is connected to the changeover switch 2 through the inverter 6, and when the power failure occurs, the changeover switch 2 is changed over so that the capacity charged in the battery 5 is discharged to pass through the inverter 6 and the changeover switch 2. The power is continuously supplied to the load 4. Since such a configuration is basically the same as that of the conventional UPS, detailed description thereof will be omitted.

Here, the life determining device in this embodiment is
First, the sensor 10 is installed close to the battery 5. The sensor 10 is composed of a sensor unit that measures the ambient temperature of the battery 5 and the terminal voltage and output current of the battery 5 for determining the discharge power of the battery. That is, the sensor 10 constitutes means for measuring the ambient temperature and electric power of the battery, respectively, and since the terminal voltage is one of the characteristic quantities showing the discharge characteristic, it also serves as the means for measuring the characteristic quantity.

Then, the measurement data detected by each sensor unit is sent to the processing unit 11, where it is determined whether or not the life has expired, and the result is output via the display unit 12 including an LED, an LCD and the like. It is supposed to do. Further, the processing unit 11 outputs an opening / closing control signal to the changeover switch 2 for generating the pseudo power failure or stopping the pseudo power failure to restore the normal operation.

The processing unit 11 will be described in detail. First, as shown in FIG. 2B, the ambient temperature and load power measured by the sensor 10, that is, the discharge power (voltage × current) of the battery 5 is determined. The voltage / time determination unit 11a inputs the determination time for performing the fuzzy inference to determine the life and the voltage drop amount serving as the determination reference value after the determination time has elapsed. In this example, the conclusion part uses a simplified fuzzy reasoning device with a singleton. Specifically, as an example, a reasoning process is performed using the membership function shown in FIG. 2 and the rule shown in FIG. , To obtain each reference value.

Here, in this example, the deterioration condition of the battery is judged in two stages, and the terminal judgment criterion which requires the replacement of the battery when the battery life is completely exhausted and the upcoming judgment criterion which can be judged that the battery life is almost reached. 2 are provided, and it is determined that the battery that also satisfies the upcoming determination criterion has not reached the end of its life. That is, assuming that the standard discharge characteristic of the battery is shown by the solid line in FIG. 4, as shown by the alternate long and short dash line in the figure, the terminal judgment criterion, which is the first criterion, is relatively shortly after the start of discharge. As soon as the voltage drops below the voltage, it is judged that the life has reached the time of replacement, and the relevant terminal judgment criteria shown by the two-dot chain line in the figure have cleared (above the reference voltage), but before the near judgment time is reached. When the voltage becomes equal to or lower than the near-judgment reference voltage, it is determined that the life is approaching. In this example, the voltage drop amount from the voltage value at the start of discharge is compared and determined for normalization. It means that the value becomes a predetermined value or more.

Then, the calculation result (each judgment standard) obtained as described above is set in the life judging section 11b in the next stage.
The life determination unit 11b has a built-in timer and outputs a pseudo power failure signal (open / close control signal) to the changeover switch 2. Further, the terminal voltage of the battery 5 is received from the sensor 10, the life of the battery is judged from the terminal voltage and the elapsed time from the start of discharge obtained from the built-in timer, and the judgment result is output to the display unit 12. Has become.

Further, as shown in FIG. 4, when discharging is performed from the floating charge state, the internal terminal of the battery is inactive as described above, so that the terminal voltage of the battery is temporarily lowered (activated) after the start of discharging. Battery is lower than the peak voltage at the start of discharging of the battery by several tens of mV), and then the voltage drop due to discharging and the increase in terminal voltage due to activation are canceled out for a certain period (several tens of seconds to 1 minute). The phenomenon that the voltage rises may be seen. Whether or not such a phenomenon occurs and the degree thereof depend on the state of the battery. Therefore, in order to make the initial condition at the time of determination constant, the initial discharge is performed for a short time to be activated and then waits for a certain time, and then the main discharge for life determination is performed. The life determining unit 11b also performs the switching control of the changeover switch 2 for the initial discharge and the main discharge. In this example, the initial discharge is performed for a predetermined time satisfying the condition of “discharge time × load power = constant”, and the initial discharge time is obtained based on the load power used when obtaining each criterion. The time is set in the life judging unit 11b, and the life judging unit 11b is set.
Then, a built-in timer generates a pseudo power failure signal (opening / closing control signal) at a predetermined timing so that power is supplied from the battery until the above predetermined time has elapsed, and the changeover switch 2
Will be switched appropriately.

Further, in this example, the load fluctuation detecting section 11c.
Is provided to detect whether there is power fluctuation during the life judgment, and if there is power fluctuation, it is not possible to accurately judge the life.Therefore, a predetermined control signal is issued to end the judgment work this time. The process is stopped by sending it to the determination unit 11b. Further, if necessary, the user is notified via the display unit 12 that the determination process has been stopped. Then, as a specific process, the load power at the start of discharge is stored and retained, and the load power constantly input during the determination process is compared with the stored load power at the start of discharge, and when both are different. It is designed to issue a stop signal.

Further, in this example, it is detected whether or not the battery 5 is in a fully charged state before the life is judged. That is, the initial conditions are unified by always determining the life of the fully charged battery 5. Then, a specific judgment is made by judging whether or not a fixed time has elapsed from the start of charging (for example, turning on the UPS power), and such judgment is built in the life judging unit 11b. Using a timer,
The life determination unit 11b makes the determination. That is, in this example, the life determination unit 11b also serves as a unit for confirming that the battery is fully charged. Then, the life determination unit 11
The timer built in b is reset / restarted in synchronism with each process, and each time required for life judgment (initial discharge time, waiting time after initial discharge, elapsed time after starting main discharge) , The elapsed time from the start of charging, etc.) is measured, and the control of the timer is also performed by the life determining unit 11b based on the internal processing status or a signal from the outside.

The life judgment is started based on the pressing of the start switch installed in the apparatus, the input of the life judgment command by the communication function, and the like. May be automatically activated at regular intervals (for example, every 1 to 2 months) using a built-in timer or clock. Then, the activation signal is given to the life determining unit 11b, and after determining whether or not the battery is fully charged, a pseudo power failure signal is generated to perform initial discharge, and the determination voltage based on the battery usage state obtained from the sensor.
The time determination unit 1a obtains each judgment standard and the like, and after a lapse of a predetermined time, the pseudo power failure is generated again to perform the main discharge to judge the life. The specific procedure is as follows.

That is, regarding the operation of the above-mentioned embodiment,
This will be described with reference to the flowchart shown in FIG. That is, when the present system is activated, first the life determination unit 11
The timer in b determines whether or not the battery is fully charged (S101). If it is not fully charged, the process is stopped (determination is impossible), and if it is fully charged, the first discharge (initial discharge) is performed.

That is, the life judging section 11b sends a pseudo power failure signal to the changeover switch 2 to supply power to the load from the voltage 5 side. Then, immediately after the start of discharge, the sensor 10
The battery output current and terminal voltage of the battery are measured using, and the load power is calculated from the product of the two. Then, it is determined whether the load power and the ambient temperature of the battery measured by the sensor 10 are within a predetermined use range. If it is not within the range of use, the life cannot be accurately determined.
Then, such determination is performed by the determination voltage / time determination unit 11a (S103, S104).

Further, fuzzy inference is performed by the judgment voltage / time determination unit 11a from the applied load power and ambient temperature, and a set of voltage drop amount and judgment time used for the end of life judgment and the judgment of near life is obtained, and Life determination unit 11b
Set to. At the same time, the time for performing the initial discharge is calculated from the load power, and the life determination unit 1
Changeover switch 2 according to the opening / closing control signal output from 1b
Is switched over (end of pseudo power failure) to return to the power supply from the commercial power source to end the initial discharge (S105, S106).

After that, a certain time (for example, 2 to 3 minutes) is waited.
During this waiting time, the battery is floatingly charged, and the energy discharged by the initial discharge is charged to return to the fully charged state. Then, after that, the changeover switch 2 is switched again to perform the pseudo power failure, and the second discharge (main discharge) is performed. At this time, the terminal voltage of the battery immediately after the start of the discharge is measured, and the terminal voltage is stored in the buffer memory in the life determining unit 11b as a reference value (peak voltage) for measuring the voltage drop amount (S1).
07).

During this pseudo power failure (life judgment), the power supply from the battery is continued, and it is judged by the load fluctuation detection unit 11c whether or not the load power at the time of performing the fuzzy inference has changed, and the load fluctuation If so, the determination is not possible, and the life determination is ended (S108).

If there is no load change, the life judging section 1
The difference (voltage drop amount) between the terminal voltage applied to 1b and the peak voltage is obtained, and it is determined whether or not the difference is equal to or more than the terminal determination voltage drop amount. If it is "equal to or more", it is determined whether the elapsed time from the start of the main discharge (detected by the timer in the life determining unit 11b) is equal to or longer than the terminal judgment time. The end of life is determined and the end of life determination is completed (S109 to S111).

If it is determined in step 110 that the voltage is less than the final-term determination voltage drop amount, or if it is determined in step 111 that it is greater than the end-of-life determination time, the process proceeds to the next close determination process. That is, the amount of voltage drop of the terminal voltage from the peak voltage is obtained in the same manner as in the final stage determination, and it is determined whether or not it has exceeded the amount of voltage drop of the near-life determination. Then, when the actual amount of voltage drop is equal to or greater than the determination reference, it is determined that the life is approaching, and the determination process ends (S112). Also,
When the actual voltage drop amount is less than the judgment reference drop amount, the process moves to the next close judgment time, the elapsed time from the start of the main discharge is compared with the near life judgment time, and when the judgment time has passed, it is judged as normal. The judgment is made and the life judgment is ended. Further, if it is still less than the near-life judgment time, it is judged whether or not the elapsed time exceeds a predetermined threshold value, and if it exceeds the threshold value, it is judged to be normal and the life judgment is ended. Also,
When the threshold is not exceeded, the process returns to step 109,
The determination process is continued (S113, 114).

When each determination process is completed, the determination result is output to the display unit 12, the changeover switch 2 is returned to the original state to end the pseudo power failure, and the power supply from the commercial power source 1 is returned. Further, in step 114, the elapsed time is compared with the threshold value because the determination time becomes long when the load power is small, and therefore when the life determination needs to be suppressed within a certain time, This is because if the amount of voltage drop is small even after the end of the stroke, the life determination is ended, and this step may be omitted.

As described above, the determination time and the voltage drop amount are appropriately set on the basis of the load capacity and the ambient temperature at that time, so that they are suitable for the actual use condition, and the determination process can be accurately performed. Moreover, since the discharging method is performed twice for the fully charged battery, the initial conditions of the battery for which the life is determined can be unified, and the determination accuracy can be further improved.

The above-mentioned embodiment shows the best embodiment of the present invention. However, as long as the initial discharge and the main discharge are performed at least twice, the specific life judgment performed during the main discharge can be performed. The present invention is not limited to the embodiment described above, and various other materials such as those disclosed in Japanese Patent Laid-Open No. 2-55536 can be applied. Further, in the above-described embodiment, two determination criteria (end period, near-term) are used, but the determination criterion may be one of whether or not it is life, and may be three or more. It can be implemented. Further, the present invention sets the number of times of the pseudo power failure to 1
Even if the life is judged only by the number of times, that is, the main discharge, at least one of the means for confirming the full charge of the battery and the means for determining the judgment standard based on the ambient temperature and the load power at the time of the life judgment is provided. In this case, the initial conditions for life judgment can be unified, and the judgment accuracy can be improved compared to the conventional one.

[0032]

As described above, in the battery life determining apparatus according to the present invention, since the main discharge is performed after the initial discharge, the temporary voltage fluctuation at the initial stage of the battery discharge does not cause any confusion. Accurate life judgment is performed. Further, when a means for confirming that the battery is fully charged is provided and the battery life is determined only when the battery is fully charged, the initial conditions are unified, and accurate life determination is possible. Also,
When the determination voltage and the determination time are obtained from the ambient temperature and the load power, the life can be determined according to the actual usage condition. Moreover, since the life is determined by using the actual load, the configuration and various controls are simplified, and
Useless energy consumption can be suppressed.

[Brief description of drawings]

FIG. 1 is a diagram showing a preferred embodiment of a battery life determining device according to the present invention.

FIG. 2 is a diagram showing fuzzy knowledge for obtaining a criterion.

FIG. 3 is a diagram showing fuzzy knowledge for determining a criterion.

FIG. 4 is a diagram illustrating the discharge characteristics of a battery and the principle of life determination in this example.

FIG. 5 is a flow chart for explaining the operation of this embodiment.

[Explanation of symbols]

 1 Commercial power supply 2 Changeover switch 3 Charger 4 Load 5 Battery 6 Inverter 10 Sensor 11 Processing unit 11a Judgment voltage / time determination unit 11b Lifespan judgment unit 11c Load fluctuation detection unit

Front page continuation (72) Inventor Yumi Tsutsumi 10 Odoron-cho, Hanazono, Ukyo-ku, Kyoto Prefecture Omron Co., Ltd. Address Within Nippon Battery Co., Ltd.

Claims (7)

[Claims] 1. A means for causing a pseudo power failure to supply power from a battery to a load, a means for measuring a characteristic amount of discharge characteristics of the battery during the pseudo power failure, and a battery based on the measured characteristic amount of the battery. And a means for determining the life of the battery, the pseudo power failure is divided into a pseudo power failure for activating the battery and a pseudo power failure again after power restoration, and during the second pseudo power failure. A battery life determination device for performing life determination. 2. A means for confirming that the battery is fully charged, a means for causing a pseudo power failure to supply power from the battery to a load, and a characteristic amount of discharge characteristics of the battery during the pseudo power failure is measured. A battery life determining device comprising means and means for determining the life of the battery based on the measured characteristic amount of the battery, and performing the life determination only when the battery is fully charged. 3. A means for measuring an ambient temperature and an electric power of a battery, a means for obtaining a life judgment criterion from the ambient temperature and an electric power, a means for causing a pseudo power failure to supply electric power from the battery to a load, and a pseudo. A means for measuring the characteristic amount of the discharge characteristic of the battery during a power failure, and the characteristic amount measured by the means for measuring the characteristic amount,
A battery life determining device comprising: a means for determining a life based on the life determining criteria. 4. The means for obtaining the life judgment criterion is for obtaining the judgment voltage and the judgment time by fuzzy inference using the ambient temperature and the electric power as input conditions.
The battery life determining device described in. 5. At least two of a means for performing a pseudo power failure in two times, a means for confirming that the battery is fully charged, and a means for obtaining a life judgment criterion from the ambient temperature and electric power are provided. A means for detecting the characteristic amount of the discharge characteristic of the battery during the pseudo power failure, and the characteristic amount detected by the means for detecting the characteristic amount,
A battery life determining device comprising: a means for determining a life based on a predetermined criterion. 6. The battery life judging device according to claim 1, wherein a plurality of judgment criteria for judging the life is provided and the degree of deterioration of the battery can be judged. 7. The method according to claim 1, further comprising means for detecting a load change during the pseudo power failure, and ending the life judgment when the load change is detected by the means. The battery life determination device described.