JP3317184B2 - Power supply device and method for detecting deterioration of power supply device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply, and more particularly to a storage battery deterioration detection circuit for detecting deterioration of a storage battery provided in a power supply.

[0002]

2. Description of the Related Art FIG. 5 is a structural view of a conventional power supply device.
Reference numeral 1 denotes a charging unit that receives a commercial power supply, and 2 denotes a storage battery that is connected to the charging unit 1 and is charged by the charging unit 1. A sensor 8 detects a discharge current, a storage battery voltage, a temperature near the storage battery, and the like. Reference numeral 9 denotes an arithmetic processing unit which calculates the deterioration state of the storage battery based on the discharge current detected by the sensor 8, the storage battery voltage, and the temperature and time near the storage battery. Reference numeral 5 denotes an alarm unit that issues an alarm by a signal from the arithmetic processing unit. Reference numeral 6 denotes an inverter which receives a DC voltage from the storage battery 2 via a sensor 8 and outputs an AC voltage. A changeover switch 7 receives a commercial power supply and the inverter 6 as inputs, and outputs one of them as a power supply to a load.

Next, the operation of this power supply device will be described. Under normal conditions, the charging means 1 inputs a commercial power supply and charges the storage battery 2. The changeover switch 7 is switched to the commercial power supply, and supplies the commercial power to the load. A description will be given of the storage battery deterioration detection operation in the steady state. When the deterioration of the storage battery is detected, the charging means 1 is stopped and the inverter 6 is turned off.
Is operated, the changeover switch 7 is switched to the inverter 6 side, and an AC voltage is supplied from the storage battery 2 to the load via the sensor 8, the inverter 6, and the changeover switch 7. At this time, the discharge current and temperature from the storage battery 2 are measured by the sensor 8. The arithmetic processing unit 9 calculates a discharge stop voltage according to the measured discharge current and temperature, and the arithmetic processing unit 9 measures a time until the discharge stop voltage is reached. At this time, when the value from the start of discharging to the time when the storage battery 2 reaches the discharge stop voltage is equal to or less than a predetermined time, the arithmetic processing unit 9 determines that the storage battery 2 is deteriorated and outputs a signal to the alarm means 5. Then, the alarm means 5 warns the user of the deterioration of the storage battery 2 by means of a buzzer, LED irradiation or the like.

FIG. 6 is a graph when a normal storage battery and a deteriorated storage battery having a constant discharge current and temperature are discharged. In the case of a normal storage battery, the time required to reach the discharge stop voltage is a specified time or more. In the case of a deteriorated storage battery, the time required to reach the discharge stop voltage is shorter than the specified time.

[0005]

However, in the conventional power supply device, the state of the battery cannot be detected unless the storage battery is discharged once, and the storage battery is not normally discharged. In an uninterruptible power supply or the like, even if the storage battery has deteriorated, it may not be accurately detected.

Further, the relationship between the discharge current of the storage battery, the voltage drop and the temperature of the storage battery, and the deterioration of the battery must be measured and stored as detailed data in an arithmetic processing unit, and a great amount of data must be obtained. In addition, there is also a problem that the cost is increased because expensive microcomputers and memories must be used.

In order to solve the above-mentioned conventional problems, the present invention provides a power supply device which can detect the deterioration of a storage battery without discharging the storage battery by a load and reduce the required data amount to be manufactured at low cost. Aim.

[0008]

In order to achieve the above object, the present invention provides a storage battery, charging means for charging the storage battery, and charging current detecting means for receiving an output of the charging means and detecting a charging current. A deterioration detecting means having a built-in timer for receiving an output from the charging current detecting means; and an alarming means for receiving an output from the deterioration detecting means, wherein a current value of the charging current detected by the charging current detecting means is provided. But,
Counts the timer above the threshold and after the specified time
And a method for detecting deterioration of the power supply device in which an alarm is issued by the alarm means when the value is equal to or higher than the threshold value, and a power supply device using the method, thereby detecting deterioration when charging the storage battery with a simple configuration. In addition, since the deterioration is constantly monitored, the deterioration can be accurately detected and an inexpensive power supply device can be provided.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings. In addition,
In the present embodiment, components having substantially the same functions as those of the conventional example are denoted by the same reference numerals.

FIG. 1 is a configuration diagram showing an embodiment of the power supply device of the present invention. Reference numeral 1 designates a charging means for inputting a commercial power supply. A storage battery 2 is charged by the charging means 1. Reference numeral 3 denotes a charging current detecting means, which is connected in series with the charging means 1 and the storage battery 2, and detects whether the charging current is equal to or less than a predetermined threshold value. Reference numeral 4 denotes a microcomputer used as deterioration detecting means, which has a built-in timer and receives a signal from the charging current detecting means 3 as an input. Reference numeral 5 denotes an alarm means such as a buzzer or an LED, which issues an alarm to the user by a signal from the microcomputer 4. Reference numeral 6 denotes an inverter which receives the DC voltage of the storage battery 2 and outputs an AC voltage. A changeover switch 7 receives a commercial power supply and the inverter 6 as inputs, and outputs one of them as a power supply to a load.

Next, the operation of the method for detecting deterioration of the power supply device will be described in detail. First, a case where the storage battery 2 before the end of its life is charged after being discharged to a load will be described. When commercial power is input to the charging means 1, the charging means 1
The storage battery 2 is charged by the charging current flowing from the output of. The charging current at this time is detected by the charging current detecting means 3, and the output from the charging current detecting means 3 to the microcomputer 4 is:
It outputs whether the charging current is larger or smaller than a predetermined threshold value.

This threshold value is set as follows for the following reason. The charging method of the charging means of the present embodiment is constant voltage / constant current charging. When charging the discharged storage battery 2, a large current flows at the beginning of charging, and when the storage battery voltage reaches a certain voltage, the charging current is reduced. It is a charging method that causes the battery to hang down. In the case of constant voltage constant current charging, the charging current at the end of charging is much smaller than the charging current at the beginning of charging. However, the charging current at the end of charging has a characteristic that it increases with the deterioration of the storage battery 2. Storage battery 2
Is composed of a plurality of cells, when the storage battery 2 deteriorates and the internal impedance of a certain cell decreases or short-circuits, the voltage applied to other cells increases, and the charging current at the end of charging decreases. growing. Therefore, a current value between the charge current value at the end of charging before the storage battery 2 reaches the end of its life and the charge current value at the end of charge after the end of the life of the storage battery 2 is set as the threshold value in advance. More specifically, the charging current flowing through the storage battery 2 was defined as an IC, the current flowing through the storage battery 2 at the end of charging when the storage battery 2 was charged before the end of life was charged, and the storage battery 2 after the end of the life was charged. In this case, when the current flowing through the storage battery 2 is ICE2 and the threshold current in the charging current detecting means 3 is ICD, the relationship between these current values is set as follows.

ICE1 <ICD <ICE2 The microcomputer 4 starts a built-in timer when the charging current IC> ICD. As shown in FIG. 2, the charging current IC at the initial stage of charging is equal to or larger than the ICD. Therefore, when the storage battery 2 is charged, the timer built in the microcomputer 4 starts. When the charging is continued and the voltage VB of the storage battery 2 reaches the constant voltage value VB1 of the charging means 1, the charging means 1 drops the charging current IC while keeping the voltage of the storage battery 2 substantially constant. After this, the charging current IC becomes IC <ICD at some point, and finally, the current value IC at the end of charging IC
E1 is reached. The timer is set to stop when IC <ICD, and the time from timer start to stop is T1. In addition, this timer is set to measure until a predetermined time T0 when the state of IC> ICD continues. Here, the relationship between T0 and T1 is set so that T1 <T0.

FIG. 2 shows the change of the voltage of the storage battery 2 and the charging current IC of the charging means 1 with time from the start of charging until the charging current reaches ICE1. This shows a case where the charging current from the initial stage of charging to immediately before dripping is substantially constant. As shown in the figure, when the IC becomes ICD within a certain time T1, the storage battery 2 is regarded as normal, and the microcomputer 4 sets the alarm means 5
A signal indicating that it is normal.

In a steady state, the changeover switch 7 is switched to the commercial power supply, and supplies the commercial power to the load. In the event of a power failure, the charging means 1 stops and the inverter 6
Is operated, the changeover switch 7 is switched to the inverter 6 side, and an AC voltage is supplied from the storage battery 2 to the load via the inverter 6 and the changeover switch 7.

Next, a case where the storage battery 2 after the end of its life is discharged and then charged will be described with reference to FIG.
Since the charging current IC> ICD at the beginning of charging, the storage battery 2
When is charged, the timer built in the microcomputer 4 starts. The charging is continued, and the voltage V of the storage battery 2 is
When B reaches the constant voltage value VB1 of the charging means 1, the charging means 1 charges the charging current I while keeping the voltage of the storage battery 2 substantially constant.
Drop C. However, the end-of-charge current ICE2 of the storage battery after the end of its life remains larger than the ICD, and the microcomputer 4 determines that the storage battery 2 has deteriorated after the timer inside the microcomputer 4 has continued measurement until the specified time T0. Then, an alarm means 5 is output to warn the user.

Next, a case where the storage battery deteriorates while charging is continued will be described with reference to FIG. Before the storage battery 2 deteriorates, the end-of-charge current is maintained at ICD or less. However, when the storage battery 2 deteriorates, the timer built in the microcomputer 4 starts when the terminal current of the charge exceeds the ICD. The microcomputer 4 also when this state IC> has elapsed T0 while sustained state of ICD determines that the storage battery 2 has deteriorated, and outputs to the alarm to the user to the alarm means 5. By the warning from the warning means 5, the power supply device of the present invention can notify the user of the deterioration of the storage battery.

In this embodiment, the charging current detecting means 3
Is described as being equal to or greater than the threshold current ICD, but the difference or the change rate of the current value of the charging current detected by the charging current detecting means 3 at the start and end of the measurement of the specified time T0 is Alternatively, it may be determined that the storage battery 2 is deteriorated when the value is equal to or less than a predetermined value, and the user may be warned by the warning means 5. In the charging current detecting means 3, the charging current is converted into a voltage or a frequency, which is detected by the microcomputer 4, and the microcomputer 4 determines whether the charging current is equal to or larger than the ICD. If the end-of-charge current does not become equal to or less than the ICD even after the lapse of T0, the microcomputer 4 may determine that the storage battery 2 has deteriorated and output an alarm to the alarm means 5. In the present embodiment, a microcomputer having a built-in timer is used as the deterioration detecting means. However, a circuit that can obtain substantially the same effect can be configured by a combination of a timer and a comparator.

It goes without saying that the effect of the present invention is particularly remarkable when it is used for a backup power supply such as an uninterruptible power supply.

[0020]

As is clear from the above embodiment, the present invention can detect the deterioration of the storage battery with a simple circuit that only detects the charging current and measures the charging time. Therefore, in devices that already use a microcomputer, it is possible to detect the deterioration of the storage battery only by adding the charging current detection means and measuring the time with the microcomputer, and to detect the deterioration of the storage battery without discharging the storage battery by the load. It is possible to supply a power supply device having an effect of being able to manufacture at low cost by detecting deterioration and reducing the required data amount.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a storage battery deterioration detection circuit according to an embodiment of the present invention.

FIG. 2 is a current-voltage correlation diagram when a pre-life storage battery is charged according to an embodiment of the present invention.

FIG. 3 is a current-voltage correlation diagram when the storage battery after deterioration is charged in one embodiment of the present invention.

FIG. 4 is a current-voltage correlation diagram when the storage battery in one embodiment of the present invention is deteriorated.

FIG. 5 is a configuration diagram of a storage battery deterioration detection circuit in a conventional example.

FIG. 6 is a current-voltage correlation diagram when a storage battery is charged in a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Charging means 2 Storage battery 3 Charging current detecting means 4 Deterioration detecting means (microcomputer) 5 Alarm means

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H02J ⁷ /00-9/08 G01R 31/36

Claims (2)

(57) [Claims] 1. A storage battery, charging means for charging the storage battery, charging current detection means for receiving the output of the charging means and detecting a charging current, and incorporating a timer for detecting an output from the charging current detection means And a warning means for receiving an output from the deterioration detecting means. The current of the charging current detected by the charging current detecting means is provided .
When the value is equal to or greater than the threshold, the timer is counted
Even after the lapse of time, the alarm
The power supply device characterized in that the step generates an alarm
Deterioration detection method . 2. The method according to claim 1, wherein the deterioration detection method comprises:
And an uninterruptible power supply.