JP2964482B2 - Method for detecting remaining capacity of lead-acid battery - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a detection method for detecting a deterioration state of a lead-acid battery facility using a float or a trickle such as an uninterruptible power supply or an emergency power supply, and a dischargeable time at the time of a power failure. Things.

2. Description of the Related Art Conventionally, as a method of detecting the life of a lead-acid battery device and the remaining capacity at the time of discharging, a method of simply detecting whether or not a constant voltage is reached only with the voltage of the storage battery, a method of detecting sulfuric acid, which is an electrolyte of the storage battery, is used. A method of detecting by specific gravity measurement, a method of detecting residual capacity by measuring differential internal resistance (Japanese Patent Application Laid-Open No. 63-168582), and a method of detecting by the degree of expansion of a positive electrode plate of a lead storage battery (Japanese Patent Application Laid-Open No. 62-47975) )and so on.

In the conventional method described above, there is no linear correlation between the voltage and the remaining capacity due to the characteristics of the lead storage battery, and there is no large change in the voltage of the storage battery until near the end of discharge. In a load in which the remaining capacity cannot be detected to near the end voltage and the discharge current fluctuates, there is a problem that the voltage fluctuates greatly and the accuracy is low.

Further, in the conventional method, it is necessary to attach a specific gravity sensor in addition to the sensors for detecting the voltage, temperature and discharge current of the lead storage battery, and it is difficult to adopt this method for a seal type lead storage battery which has been increasing in recent years. Also, conventional open-type storage batteries are not practical because it takes a long time to equalize the specific gravity after charging.

Next, in the conventional method, in order to measure the differential resistance of the storage battery, it is necessary to apply a large current for a short time and measure it from the IR drop at that time, or install an internal ohmmeter by the AC method. In addition, depending on the cause of deterioration of the lead storage battery such as softening of the positive electrode active material of the lead storage battery, the discharge duration may be short even though the differential resistance of the storage battery is low, and the reliability of the detection result is low. .

The conventional methods have the disadvantages that a displacement detection sensor is required, and that the remaining capacity at the time of a power failure cannot be detected even if the life of the storage battery can be detected from the displacement.

The above four methods have a disadvantage that the remaining dischargeable time cannot be detected in real time with respect to a fluctuating load.

As a means for eliminating the above-mentioned drawbacks, the present inventors have disclosed, as shown in Japanese Patent Application Laid-Open No. 2-170372, voltage data and discharge current data of a lead storage battery at regular time intervals when the storage battery is discharged due to a power failure or the like.・ Read the temperature data, calculate the integral of the amount of discharge from the discharge current data and the elapsed time, select the desired discharge end voltage and the standard discharge characteristic data sequence close to the current temperature data, and measure the discharge current data A method of calculating the expected duration of time from the intersection of the measured values of the standard discharge characteristic data and the discharge current data at the two points before and after, and sequentially calculating the remaining dischargeable time from the expected duration of time and the amount of discharged electricity to the discharge end voltage Suggested.

However, the above proposal is an effective means during the period when the storage battery equipment can maintain the initial discharge performance, but with the use period of the storage battery, even when the discharge performance is degraded,
At the time of the actual power failure, the discharge characteristics data at the initial stage of the discharge often hardly differ from the standard discharge characteristics data sequence, making it difficult to detect the accurate remaining capacity. It is only possible to detect that there is a tendency of deterioration compared to the discharge characteristic data sequence.

The present invention solves the above-mentioned drawbacks that occur in the case of a storage battery whose discharge performance has deteriorated, and provides a means for detecting the true remaining dischargeable time after a power failure with higher accuracy even at the initial discharge than in the previous proposal. The purpose is to do.

Means for Solving the Problems The present invention sequentially calculates and displays the true remaining dischargeable time up to the discharge end voltage when a power outage or a simulated power outage is periodically generated, and until the end of discharge corresponding to the power outage recovery. By adding a learning function to calculate the deterioration rate by comparing the discharge characteristic data of the storage battery with the standard discharge characteristic data sequence and store the result in the storage device,
At the time of the next power outage, the time obtained by simply multiplying the tentative duration calculated by simply comparing the standard discharge characteristic data sequence with the deterioration rate can be used as the true expected duration, and the time already elapsed is subtracted from the true expected duration. Thus, even at the initial stage of discharging the storage battery, the true remaining dischargeable time of the storage battery can be accurately detected and displayed.

The present invention can accurately detect and display the true remaining dischargeable time of a storage battery whose discharge performance has been degraded by the above method, regardless of whether it is at the beginning of charging or not. Also, by displaying the true remaining dischargeable time and deterioration status, it becomes easy to determine the life degradation of the storage battery,
By performing an alarm or the like on the replacement time of the storage battery facility, maintenance such as replacement of the storage battery facility by an administrator or a user can be easily performed.

Examples Examples of the present invention will be described below. FIG. 1 is a block diagram of a true remaining dischargeable time detection part of a storage battery equipment monitoring device according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a microprocessor which is a control unit, and 2 denotes a program for sequentially calculating and displaying a true remaining dischargeable time of a storage battery after a power failure or a pseudo power failure is detected and after a power failure or a pseudo power failure. A program memory 3 stores a standard discharge characteristic data array and a deterioration rate for each temperature and discharge end voltage of the storage battery. Reference numeral 4 denotes an input / output interface, which includes operating devices such as a keyboard and a panel switch 5, a display device 6 for displaying the true remaining dischargeable time of the storage battery, temperature data 8, storage battery voltage data 9, and discharge current data 10. Connect an A / D converter 7 to be imported to the computer.

Next, a description will be given, with reference to the flowchart of FIG. 2, of a process of calculating a true remaining dischargeable time at the time of a power failure by the monitoring device.

In S11, first, when the monitoring device detects a power failure due to an increase in the contact signal or the battery discharge current data 10, the S1
In step 2, the storage battery voltage data 9, temperature data 8, and discharge current data 10 are read.

Then, in S13, the amount of discharge electricity is integrated based on the discharge current data 10 from the start of discharge and the elapsed time.

Next, in S14, the standard discharge characteristic of the temperature corresponding to the discharge end voltage of the storage battery previously set by the keyboard 5 or the like from the memory 3 storing the standard discharge characteristic data array and closest to the current temperature data 8 Select the data sequence, take out the standard discharge characteristic data at the two points closest to the actual measured value of the discharge current data 10 from the selected standard discharge characteristic data sequence, and measure the actual measured value of the discharge current data 10 read in S12. And calculate the dischargeable time in the fully charged state. This is a temporary duration that does not take into account the deterioration of the storage battery.

Then, in S15, the tentative duration obtained in S14 is multiplied by the deterioration rate (≦ 1) to obtain a true expected duration.

Thereafter, in S16, the value obtained by dividing the amount of discharge electricity integrated in S13 by the actually measured value of the discharge current data 10 is used as the time that has already elapsed, and is subtracted from the true expected duration obtained in S15 to obtain the true remaining discharge. It is possible time.

In the present embodiment, the true remaining dischargeable time calculated in S16 in S18 is displayed on the display device 6.

Then, in S19, it is determined whether or not the power failure has been recovered by the discharge current data 10, etc., and if not recovered, the process of S12 returns, the same process is repeated, and the true remaining dischargeable time is updated in S18. indicate.

When the power outage is recovered, in step S20, the final discharge characteristic data at the time of the power outage is compared with the selected standard discharge characteristic data sequence to determine the deterioration rate, and in step S21, the deterioration rate is stored in the storage device. Then, the process returns to the normal monitoring mode in S22. When the normal discharge performance is not deteriorated or when the actual discharge elapsed time is longer than the standard characteristic data sequence, the deterioration rate is set to the initial value of 1.

Fig. 3 shows the construction of a float charging circuit using a constant current load equivalent to 0.25 CA in a 48V 30Ah storage battery facility in an atmosphere of + 45 ° C, and a pseudo power failure once a month to discharge to 42V. Is a comparison of the calculated value of the dischargeable time at 5 minutes after the start of the power failure and the error (absolute value) between the actual dischargeable time and the result calculated by the previously proposed method and the method of the present invention. . As described above, the value of the true remaining dischargeable time predicted and detected by the method of the present invention elapses with an error of about ± 5% from the actual value. On the other hand, the method proposed earlier resulted in an error increasing as the storage battery deteriorated.

Effects of the Invention As described in detail above, the method of the present invention can accurately predict and calculate the true remaining dischargeable time at the initial stage of discharge, that is, at the early stage of power failure even if the discharge performance of the storage battery equipment has deteriorated, This is an extremely effective means.

[Brief description of the drawings]

FIG. 1 is a block diagram of a storage battery facility monitoring apparatus according to the method of the present invention, FIG. 2 is a flowchart showing a process of calculating the true remaining dischargeable time, and FIG. It is a figure which shows the difference | error between the true remaining dischargeable time estimated and calculated and the actual dischargeable time. 1 ... Microprocessor, 3 ... Storage device storing standard discharge characteristic data, 7 ... A / D for reading temperature data, storage battery voltage data, discharge current data
Converter 23, transition of error by the method of the present invention,
24… The transition of the error by the method proposed earlier.

Continuation of the front page (72) Inventor Kazumi Yamaguchi 1006 Kazuma Kadoma, Kazuma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-2-260078 (JP, A) JP-A-2-170372 (JP) , A) (58) Field surveyed (Int. Cl. ⁶ , DB name) G01R 31/36 H02J 7/00 H01M 10/42-10/48

Claims (1)

(57) [Claims] 1. The relationship between the discharge current of a lead storage battery for each temperature and the dischargeable time for each discharge end voltage is stored in advance in a storage device as a standard discharge characteristic data array, and the voltage of the lead storage battery at the time of a power failure or a pseudo power failure is stored. Reads data, discharge current data, and temperature data, calculates the integral of the amount of discharge from the discharge current data and elapsed time, and selects a standard discharge characteristic data sequence close to the desired discharge end voltage and current temperature data, and discharges. The expected duration is obtained from the intersection of the standard discharge characteristic data at two points before and after the actual measured value of the current data and the actual measured value of the discharge current data, and the remaining dischargeable time is calculated from the expected duration and the amount of discharged electricity. This is a method for detecting the remaining capacity of a lead storage battery, and compares the discharge characteristic data sequence at the time of power failure or pseudo power failure with the standard discharge characteristic data sequence. Then, the deterioration rate of the storage battery is calculated and stored in the storage device, and at the time of the next power outage or pseudo power outage, a calculation is performed by multiplying the temporary expected duration by the deterioration rate, and the true remaining dischargeable time is detected. A method for detecting a remaining capacity of a lead storage battery.