JPH10285827A - Lie detecting method for sealed battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce loss in discharging by causing a discharge current to flow into a load from a sealed battery at each set period, and comparing the lowering of the voltage of the sealed battery as against the unit current time product of the discharge current with a reference value. SOLUTION: A timer circuit 11 for setting the detection period of this apparatus outputs a starting command to a command to a timer circuit 12 and a compactor 14, when a set long time passes and the time is up. Incidentally, the timer circuit 12 is being set to a comparatively short time, and in counting, a current flowing into an inverter 5 from a battery 7 is detected by a current detector 17, and the voltage of the battery 7 is detected by a voltage detector 13, and both detected signals are inputted to a comparator 14. The lowered value of the detected voltage signal to a unit current time product obtained by multiplying the detected current signal by a period is sampled, and compared with a reference value of a reference value outputting circuit 15. An alarm is displayed on an alarm display 16, when the lowering of the battery voltage has become larger than the reference value. Consequently, it becomes possible to exchange the battery surely, when it reaches an appropriate life lowered state.

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 detects a decrease in the life of a sealed storage battery incorporated in an uninterruptible power supply and displays an alarm.

[0002]

2. Description of the Related Art Conventionally, a small uninterruptible power supply having an inverter configuration is used for a power failure backup of a computer device and its application device. This uninterruptible power supply incorporates a small sealed lead-acid battery as a backup power supply that is easy to maintain, small and easy to assemble, and converts the energy of the sealed lead-acid battery to AC by an inverter when a commercial power failure occurs. Supply to the load to continue the load power supply.

[0003] Incidentally, the sealed lead-acid battery has a problem in that the anode plate is corroded and elongated by use, the production of lead sulfate (PbSO4) and the like, the release of moisture (steam) from the surface of the battery case, and the hydrogen (H2 ), The life is shortened due to a decrease in the amount of liquid due to the escape of oxygen (O2) gas.

[0004] If the uninterruptible power supply is continued to be used in a lowered state that requires battery replacement, not only will the uninterruptible power supply not function properly, but also liquid leakage, electric leakage, smoke generation, ignition, etc. due to cracks in the battery case will occur. Therefore, when the life of the sealed lead storage battery is shortened, it is necessary to replace the storage battery. For example, a predetermined amount of discharge current is passed from the sealed storage battery of the uninterruptible power supply to the discharge circuit for a certain period of time, for example, 2 to 5 minutes at intervals of about two weeks to several months. The life of the storage battery is detected from comparison with a reference value.

[0005]

Since the sealed storage battery causes a discharge current to flow through the discharge circuit every set period, the loss is large and the discharge circuit requires a large capacity, and the uninterruptible power supply becomes large. There is a problem.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a sealed storage battery, a rectifier for rectifying a commercial AC power supply and controlling the output, and floatingly charging the sealed storage battery, and a rectifier. In the method for detecting the life of a sealed storage battery of an uninterruptible power supply, comprising a DC output or an output of the sealed storage battery as an input and an inverter that converts the output to an AC power supply equivalent to a commercial AC power supply, The DC output of the rectifier is reduced, and a discharge current flows from the sealed storage battery to the load via the inverter. When a decrease in the battery voltage of the sealed storage battery with respect to a unit current-time product by the discharge current is larger than a reference value, This is to detect a decrease in the life of the sealed storage battery and display an alarm.

That is, the DC output of the rectifier is reduced every set period, and a discharge current flows from the sealed storage battery to the load via the inverter. At this time, the discharge current and the battery voltage are detected, and the decrease in the battery voltage of the sealed storage battery with respect to the unit current-time product of the discharge current is compared with a reference value. if,
When the decrease in the battery voltage of the sealed storage battery with respect to the unit current-time product does not reach the reference value and is small, the DC output of the rectifier is returned to the initial value. On the other hand, when the life of the sealed storage battery decreases and the decrease in the battery voltage of the sealed storage battery becomes larger than the reference value, the reduced life of the sealed storage battery is detected and an alarm is displayed.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. In FIG. 1, reference numeral 1 denotes an uninterruptible power supply having an inverter configuration, 2 denotes a power input terminal of the power supply 1, 3 denotes a rectifier, and 4 drives a power control element incorporated in the rectifier.
A drive circuit for controlling the output, 5 is an inverter, 6 is an output switch having an AC switch configuration, and 7 is a sealed storage battery as a power source for backup.

Reference numeral 10 denotes a load of a computer device, its application, etc., 11 denotes a long-time timer circuit, 12 denotes a short-time timer circuit, 13 denotes a voltage detector, 14 denotes a comparator, 15 denotes a reference value output circuit, and 16 denotes an alarm. An indicator 17 is a current detector.

Next, the operation of the power supply device 1 based on normal (power supply) and power failure of the commercial AC power supply will be described. First, when the commercial AC power supply is normal (when power is supplied), the commercial AC power supply is supplied to the rectifier 3 and the output switch 6 via the power input terminal 2. At this time, the rectifier 2 is driven by the drive circuit 4 and output-controlled to float-charge the sealed storage battery 7 and supply a DC output to the inverter 5. The DC output is converted into an AC power supply equivalent to a commercial AC power supply by the inverter 5, and the AC power supply is supplied to the output switch 6.

Since the output switch 6 is held in a selected state of the output of the inverter 5 by manual operation, for example, except when a failure occurs in the rectifier 3 and the inverter 5 and when the power supply device 1 is checked, the output switch 6 is based on a commercial AC power supply. The output of the inverter 5 is supplied to the load 10.

Next, when the commercial AC power supply fails, the rectifier 3
, The stored energy of the storage battery 7 is supplied to the inverter 5 instead of the DC power supply of the rectifier 3.
Based on this supply, the inverter 5 continues to operate, the AC power of the inverter 5 continues to be supplied to the load 10, and the power failure backup is performed. When the commercial AC power supply returns to the normal state after returning from the power failure, the DC output of the rectifier 3 is supplied to the inverter 5 again. In addition, the storage battery 7 that has released energy by supplying power to the inverter 5 is thereafter recovered and charged, and finally shifts to floating charging.

Next, detection of a decrease in the life of the storage battery will be described. First, the timer circuit 11 for setting the detection cycle is
A relatively long period of one to several months is set as the counting period based on the discharge characteristics of the storage battery 7. Then, the timer circuit 11 operates by applying the voltage of the storage battery 7, and counts, for example, a clock signal of a clock circuit (not shown).
During this counting, the output of the timer circuit 11 is kept off, and the start command from the long-time timer circuit 12 to the short-time timer circuit 13 and the comparator 14 is both turned off.
3 and the comparator 14 have stopped operating.

Next, when the set long time elapses, the timer circuit 11 times out and outputs a start command to the timer circuit 12 and the comparator 14. The short-time timer circuit 12 operates to calculate, for example, a clock signal of a clock circuit (not shown). During this counting, the short-time timer circuit 12
To control the drive circuit 4 to lower the output voltage of the rectifier 3 below the terminal voltage (battery voltage) of the storage battery 7. Due to the decrease in the DC output of the rectifier 3, the energy stored in the sealed storage battery 7 is supplied to the inverter 5, the inverter 5 continues to operate, and the AC power of the inverter 5 is supplied to the load 10.

The current flowing through the load 10 causes the storage battery 7
The battery voltage decreases as the discharge time elapses, and its characteristics change from a solid line to a broken line as shown in FIG. FIG. 2 shows the characteristics at the time of normal operation, and the broken line shows the characteristics at the time of shortened life.

The timer circuit 12 is set for a relatively short time, for example, about 2 to 5 minutes. When the timer circuit 12 counts, the current detector 17 detects the current flowing from the storage battery 7 to the inverter 5, the voltage detector 13 detects the battery voltage of the storage battery 7, and both detection signals are input to the comparator 14. You. The comparator 14 samples a decrease value of the voltage detection signal with respect to a unit current-time product obtained by integrating the current detection signal and the period, and compares the sampled value with a value of the reference value output circuit 15.

If the sampling value has not reached the reference value, the storage battery is in a normal state as shown by the solid line in FIG. Then, no alarm output is output from the comparator 14. Therefore, when a short time of the set timer circuit 12 elapses, the timer circuit 12 times out and outputs a reset signal to the timer circuit 11. The long-time timer circuit 11 is reset by the reset signal, and the long-time timer circuit 11 starts counting. Further, the drive signal is output to the drive circuit 4 by the time-up of the timer circuit 12, the rectifier 3 outputs the initial output voltage, and the storage battery 7 performs the recovery charge and the floating charge.

If the sampling value has reached the reference value, that is, if the battery voltage has dropped below the reference value, an alarm output is output from the comparator 14 and the alarm display 1
6 indicates an alarm. For this reason, the reduced life of the storage battery 7 is automatically detected and an alarm is displayed. Based on the display, the storage battery 7 can be reliably replaced when the appropriate reduced life state is reached.

[0019]

As described above, according to the present invention, since the sealed storage battery is discharged via the load at every set period, the loss is small and there is no need to provide a special discharge circuit which was conventionally required, and the uninterruptible power supply is not required. The device can be downsized.

[Brief description of the drawings]

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

FIG. 2 is a discharge characteristic diagram of a sealed storage battery.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Uninterruptible power supply tank 2 Rectifier 4 Drive circuit 5 Inverter 7 Seal storage battery 10 Load 11 Long time timer circuit 12 Short time timer circuit 13 Voltage detector 14 Comparator 15 Reference value output circuit 16 Alarm display 17 Current detector

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H02J 9/06 504 H02J 9/06 504B

Claims (1)

[Claims] 1. A rectifier for rectifying and controlling the output of a sealed storage battery and a commercial AC power supply and for floatingly charging the sealed storage battery, and a dc output of the rectifier or an output of the sealed storage battery as an input. In the method for detecting the life of a sealed storage battery of an uninterruptible power supply comprising an inverter for converting to an equivalent AC power supply, the DC output of the rectifier is reduced every set period, and the sealed storage battery is connected to the inverter via the inverter. A discharge current is supplied to the load, and when a decrease in the battery voltage of the sealed storage battery with respect to a unit current-time product by the discharge current is larger than a reference value, a decrease in the life of the sealed storage battery is detected and an alarm is displayed. A method for detecting the life of a sealed storage battery.