JPH0554915A - Detection of life for sealed storage battery - Google Patents

Abstract

PURPOSE:To detect a reduction of a life of a sealed storage battery included in an uninterruptive power supply correctly in procedures applicable to automation by comparing a voltage at each cell with a reference voltage in order periodically, and displaying an alarm when it is lower than the reference voltage. CONSTITUTION:A CPU 14 takes digital data for a voltage for each cell of a sealed storage battery 7 included in an uninterruptive power supply unit 1 outputted from an A/D converter 13 every set period, and outputs it to a D/A converter 15. A detected voltage for each cell outputted from the converter in order is taken into a comparator 17 to be compared with a reference voltage of a reference voltage outputting circuit 16. At this time, if any one of the detected voltages of the cells is lower than the reference voltage, the comparator supplies a display instruction to an alarm display 18 instead of supplying a reset signal to a timer circuit 11. In this constitution, reduction of a life can be detected correctly in procedures applicable to automation, thereby the sealed storage battery can be replaced in a proper life-reduced condition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting the life of a sealed storage battery, which accurately detects a decrease in the life of a sealed storage battery having a plurality of cells built in an uninterruptible power supply by a method suitable for automation and displays an alarm. ..

[0002]

2. Description of the Related Art Conventionally, a small uninterruptible power supply unit having an inverter structure is used for backing up a power failure of a computer device and its applied device. This uninterruptible power supply has a built-in small sealed lead acid battery as a backup power source that is easy to maintain, small, and easy to assemble, and converts the energy of the sealed lead acid battery into alternating current by an inverter when the commercial power fails. Supply to the load to continue the load power supply.

By the way, the sealed lead-acid battery is usually
Formed by multiple cells (unit cells), for example 700W
When used in a 1KVA uninterruptible power supply capable of compensating for a 10-minute power outage of the above load, it is formed by a total of 15 assembled batteries (total 90 cells) in units of a series circuit of 6 cells (2AH). .. Then, each cell is initially charged to a fully charged state of, for example, 2.27 V / cell, and the voltage difference between cells is extremely small.

However, when the battery is incorporated into the power supply device and repeatedly charged and discharged, each cell of the sealed lead acid battery is corroded and stretched by use, the production of lead sulfate (PbSO ₄ ) is generated, and the cells from the surface of the battery case are removed. Water (vapor) is released, hydrogen (H ₂ ) and oxygen (O ₂ ) are released due to electrolysis of water, and the gas is released, resulting in deterioration of the liquid amount and the like, and the life is gradually reduced. At this time, even if the voltage of the storage battery (battery voltage) is maintained at the rated value, a difference occurs in the voltage of each cell due to the variation in the life of each cell.

When any one of the cells has reached the end of its life, the remaining cells share the voltage of the damaged cell, so that the cells suddenly deteriorate and reach the end of their life.

If the storage battery is continuously used in a state where the battery needs to be replaced after it has reached the end of its life, not only the uninterruptible power supply unit will not function normally, but also liquid leakage, electric leakage, smoke, ignition, etc. due to cracking of the battery case will occur. Lead to a situation. Therefore, it is necessary to accurately detect the life reduction of the sealed lead acid battery and replace the battery.

[0007]

Conventionally, the shortened life of the sealed lead acid battery having a plurality of cells has not been detected. And since the standard of life reduction is generally 3 years,
For example, the storage battery is replaced every three years. Therefore, there is a problem that the storage battery is not replaced in an appropriate life shortening state, and the liquid leakage, electric leakage, smoke generation, ignition, etc. may occur during use in some cases.

According to the present invention, a shortened life of a sealed storage battery having a plurality of cells, such as a sealed lead storage battery of an uninterruptible power supply, is accurately detected by an appropriate method for automation, and an alarm is displayed. It is intended to be exchanged.

[0009]

In order to achieve the above object, in the method for detecting the life of a sealed storage battery according to the present invention, in the case of claim 1, each of the sealed storage batteries of the uninterruptible power supply device is set for each set period. The cell voltage is sequentially compared with a reference voltage, and when any one of the cell voltages is lower than the reference voltage, a decrease in the life of the storage battery is detected and an alarm is displayed.

In the second aspect, the voltage of each assembled battery of a plurality of cells of the sealed storage battery of the uninterruptible power supply device is sequentially compared with the reference voltage for each set period, and one of the voltages of each assembled battery is compared. At any time, when the voltage is lower than the reference voltage, a decrease in the life of the storage battery is detected and an alarm is displayed.

[0011]

In the case of the method for detecting the life of the sealed storage battery of the present invention configured as described above, for example, the voltage of each cell of the storage battery or each assembled battery of a plurality of cells is periodically set for each period of about 2 weeks to several months. When any one of the voltages of each cell or each assembled battery becomes lower than the reference voltage and the replacement time is reached, the life shortening is detected and an alarm is displayed. Therefore, the shortening of the life of the sealed storage battery having a plurality of cells is accurately detected and notified by a method suitable for automation.

[0012]

EXAMPLES Examples will be described with reference to FIGS. 1 to 3. (One Embodiment) First, one embodiment will be described with reference to FIGS. In FIG. 1, 1 is an uninterruptible power supply device having an inverter configuration, 2 is a power supply input terminal of the power supply device 3,
Is a noise filter, 4 is a rectifier, 5 is an inverter, 6 is an output switcher having an AC switch configuration, 7 is a sealed lead-acid battery as a backup power source, and 8 is a sealed storage battery.
Is a charger, and 9 is a diode for preventing backflow.

Reference numeral 10 is a load of a computer device, its application device, etc., 11 is a long time timer, 12 is a voltage detector, and 13 is a voltage detector.
Is an A / D converter, 14 is a microcomputer (hereinafter referred to as CPU) having a multiplexer function, and 15 is D /
A converter, 16 is a reference value output circuit, 17 is a comparator, 18
Is an alarm indicator.

The storage battery 7 is formed by a series circuit of six cells 7a, ..., 7f as shown in FIG. 2, for example, and the voltages of the cells 7a to 7f are constantly input in parallel to the voltage detector 12. Next, normal commercial AC power supply (power supply),
The operation of the power supply device 1 based on a power failure will be described. First, when the commercial AC power supply is normal (at the time of power supply), the commercial AC power supply is supplied to the noise filter 3 via the power supply input terminal 2, and the line noise superimposed on the commercial AC power supply is removed by the filter 3 to ensure normal operation. A sine wave AC power source is supplied to the rectifier 4 and the output switcher 6.

Further, the DC power converted and formed by the rectifier 4 is supplied to an inverter 5, which converts the DC power into an AC power equivalent to a commercial AC power, and this AC power is supplied to an output switcher 6. To be done. The output switch 6 is held in the selected state of the output of the inverter 5 by manual operation, for example, except when a failure occurs in the rectifier 4 and the inverter 5 and when the power supply device 1 is inspected.

Therefore, the output of the inverter 5 based on the commercial AC power source is supplied to the load 10. The storage battery 7 is charged by the charger 8 based on a manual or automatic charging command.

Next, when the commercial AC power supply fails, the output voltage of the rectifier 4 decreases, and the stored energy of the storage battery 7 is supplied to the inverter 5 via the diode 9 instead of the DC power supply of the rectifier 4. Inverter 5 based on this supply
Continues to operate, AC power of the inverter 5 is continuously supplied to the load 10, and power failure backup is performed.

When the commercial AC power is restored to normal after the power failure, the DC power of the rectifier 4 is supplied to the inverter 5 again. Further, the storage battery 7 which has released energy by supplying power to the inverter 5 is recovered and charged by a subsequent charge command.

Next, detection of shortening of the life of the storage battery 7 will be described. First, the voltage of each of the cells 7a to 7f of the storage battery 7 is constantly detected by the voltage detector 12, and this detector 12
The detection voltage of each of the cells 7a to 7f is converted into digital data by the A / D converter 13 and constantly supplied to the CPU 14.

On the other hand, the timer circuit 11 for setting the detection cycle
Is set to a relatively long period of about 2 weeks to several months as the counting period based on the discharge characteristics of the storage battery 7. Then, the timer circuit 11 operates by the voltage application of the storage battery 7, and counts the clock signal of a clock circuit (not shown), for example.

During this counting, the output of the timer circuit 11 is held off, and the timer circuit 11 allows the CPU 14 and the comparator 1 to operate.
No start command is issued to 7, and both the CPU 14 and the comparator 17 are held in a stopped state. Then, when the set period is reached, the timer circuit 11 enters a time-up state and outputs a start command to the CPU 14 and the comparator 17.

This command causes the CPU 14 and the comparator 17 to operate, and the CPU 14 takes in digital data of the voltages of the cells 7a to 7f output from the A / D converter 13 immediately after the command is input, and keeps these data constant. The signals are sequentially output to the D / A converter 15 at intervals and converted into an analog detection voltage. Then, the detection voltage of each of the cells 7a to 7f sequentially output from the D / A converter 15 is taken into the comparator 17 and compared with the reference voltage for detecting the life reduction of the output circuit 16.

At this time, the detected voltage of the D / A converter 15 becomes higher than the reference voltage of the output circuit 16 for a healthy cell, but the D / A converter 1 for a cell having a shortened life.
The detection voltage of 5 becomes lower than the reference voltage of the output circuit 16.

When the detection voltage of the D / A converter 15 is higher than the reference voltage of the output circuit 16 for all the cells 17a to 17f and the storage battery 7 is healthy, the comparison is completed by ending the comparison of the last cell 17f. A reset signal is issued from the device 17 to the timer circuit 11, and the timer circuit 11 is instantly reset by this signal to start counting. In addition,
The momentary reset turns off the start command of the timer circuit 11, and the CPU 14 and the comparator 17 stop operating and return to the initial state.

After that, each time the timer circuit 11 reaches the time-up state, the voltages of the cells 7a to 7f of the storage battery 7 are sequentially inspected to detect the life thereof. When the life of any of the cells 7a to 7f decreases and the detected voltage becomes lower than the reference voltage, the comparator 17 causes the timer circuit 11 to operate.
Instead of supplying a reset signal to the alarm display unit 18, a display command is supplied to the alarm display unit 18, and the display unit 16 displays an alarm indicating that the service life has decreased.

Therefore, one of the cells 7a to 7f
When the life of the storage battery 7 is exhausted at any time, a decrease in the life of the storage battery 7 is automatically detected and an alarm is displayed. Based on this display, the storage battery 7 can be reliably replaced when the appropriate life shortened state is reached.

By the way, in the above embodiment, the detection of the voltage of the storage battery 7 cell by cell was repeated to detect the shortening of the service life. However, as in the case of the sealed storage battery having a large number of cells, for example, the sealed lead storage battery of the above 1 KVA uninterruptible power supply. In the case of a sealed storage battery consisting of 15 assembled batteries (90 cells in total) in units of a 6-cell series circuit, the number of voltage comparisons for each inspection is reduced, and the inspection time is shortened for quick detection. Instead of detecting the voltage of each cell, the voltage of each battery pack may be detected. In this case, for example, the voltage of each of the assembled batteries forming the storage battery may be supplied to the voltage detector 12 of FIG. The reference voltage of the output circuit 16 is, of course, different between the cell unit detection and the battery pack unit detection.

(Other Embodiments) Next, other embodiments will be described with reference to FIG. In FIG. 3, the same reference numerals as those in FIG. 1 indicate the same or corresponding ones, except that the temperature sensor 19 and the humidity sensor 20 for detecting the temperature and humidity of the usage environment of the storage battery 7 and the outputs of both sensors 19, 20. A calibration memory for adding the A / D converters 21 and 22 for converting the signals into digital data and outputting the detected temperature and detected humidity data, and operating the CPU 14 with the data of both converters 21 and 22 as read addresses. Is incorporated, and a setting update signal for correction is supplied from this memory to the output circuit 16 to adjust the reference voltage for detecting the life shortening according to the temperature and humidity.

That is, since the characteristics of the storage battery 7 are likely to change depending on the temperature and humidity of the atmosphere, in this embodiment, the sensors 19 and 20 monitor and detect the temperature and humidity of the operating environment, and both sensors 19 and 20 C based on the digital data of the temperature and humidity detected by the converters 21 and 22 based on the output signal of 20.
It is supplied to the PU 14 as a read address of the calibration memory.

Then, the calibration memory of the CPU 14 stores the temperature,
Data of optimum correction values for various combinations of humidity is written in each address, and for example, by the operation of the CPU 14 based on the start command of the timer circuit 11, when the detected temperature and the detected humidity are detected in accordance with the given read address. The data of the optimum correction value is read out to the output circuit 16 as a setting update signal.

At this time, unlike the case of FIG. 1, the output circuit 16 increases or decreases the reference voltage output to the comparator 17 based on the supply of the setting update signal, for example, by the data amount of this signal.

Therefore, by comparing the cell unit or the assembled battery unit of the comparator 17, the life shortening of the storage battery 7 is detected in consideration of the temperature and humidity of the use environment, and the detection accuracy is remarkably improved. By the way, in the above both embodiments, the invention is applied to the detection of the life shortening of the storage battery 7 of the power supply device 1 of the inverter configuration, but it is applied to the detection of the life reduction of various sealed storage batteries of the uninterruptible power supply device of various configurations of a plurality of cells. Of course you can.

[0033]

Since the present invention is configured as described above, it has the following effects. For each set period, the voltage of each cell or assembled battery of the uninterruptible power supply seal storage battery is sequentially compared with the reference voltage for inspection, and any one of the voltage of each cell or assembled battery is checked. When the battery voltage becomes lower than the reference voltage and the time to replace the storage battery is reached, the decrease in the life of the storage battery is detected and an alarm is displayed, so a method suitable for automation can accurately detect and notify the decrease in the life of the storage battery, Based on this notification, the storage battery can be replaced with an appropriately shortened life, and safety and the like can be improved.

Further, when the voltage comparison is performed in units of a plurality of assembled battery cells, the number of voltage comparisons can be reduced and detection can be performed quickly, especially for a sealed storage battery having a large number of cells.

[Brief description of drawings]

FIG. 1 is a block diagram of one embodiment of a method for detecting the life of a sealed storage battery according to the present invention.

FIG. 2 is an explanatory diagram of a configuration of a sealed storage battery.

FIG. 3 is a block diagram of another embodiment of the present invention.

[Explanation of symbols]

 1 Uninterruptible Power Supply 7 Sealed Storage Battery 7a-7f Cell 11 Long Time Timer 12 Voltage Detector 16 Reference Value Output Circuit 17 Comparator 18 Alarm Indicator

Claims (2)

[Claims] 1. The voltage of each cell of a sealed storage battery of an uninterruptible power supply is sequentially compared with a reference voltage for each set period, and when any one of the voltages of each cell is lower than the reference voltage, the A method for detecting the life of a sealed storage battery, which comprises detecting a decrease in the life of the storage battery and displaying an alarm. 2. The voltage of each assembled battery having a plurality of cells of a sealed storage battery of an uninterruptible power supply is sequentially compared with a reference voltage for each set period, and any one of the voltages of each assembled battery is used as the reference. A method for detecting the life of a sealed storage battery, comprising detecting a decrease in the life of the storage battery when the voltage is lower than the voltage and displaying an alarm.