JPH04372536A - Electronic equipment using storage battery - Google Patents

Abstract

PURPOSE:To detect the state of a storage battery automatically without requiring time or labor from a user, etc., and without discharging the storage battery to exert an influence upon the life of the battery. CONSTITUTION:According to instructions of a UPS(uninterruptible power supply) control circuit 11, a charging voltage instruction circuit 12 successively gives a charging circuit 13 instructions to apply a voltage lower than the optimum charging voltage of the storage battery 4, the optimum charging voltage and a voltage higher than the optimum charging voltage to the storage battery 4, and the charging circuit 13 charges the storage battery 4 according to these instructions. A current detection sensor 14 detects the value of a charging current iB supplied to the storage battery 4 at that time and sends the value to a charging current discrimination circuit 15. The charging current discrimination circuit 15 compares the value of the charging current iB with a charge completion current value obtained when the storage battery 4 is normal and in a charge completion state, disriminates the state of the storage battery, i.e., a normal state, overdischarge state or deterioration state caused by a high impedance deterioration, etc., and sends a discrimination signal to the UPS control circuit 11.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to electronic equipment using storage batteries, such as uninterruptible power supplies.

0002

[Prior Art] Conventionally, electronic devices using storage batteries include
For example, there is an uninterruptible power supply device that uses a storage battery shown in FIG. 5 as an auxiliary power source.

[0003] During normal use, this device outputs current from a commercial power source, which is an external power source, through a rectifier circuit 1 and a DC-AC inverter circuit 2 to power a computer (not shown).
When the current from the commercial power supply stops or there is an abnormality, the output switching relay 5 is turned on to supply current from the storage battery 4 to the load. During normal use, the storage battery 4 is charged by controlling the rectification and charging voltage by the charging circuit 3.

0004

[Problem to be Solved by the Invention] By the way, in such an uninterruptible power supply, when it is actually necessary to supply current from the storage battery, in order to properly supply power from the storage battery, it is necessary to check the state of charge of the storage battery and the like. It is necessary to detect the deterioration state.

[0005] However, with the above-mentioned conventional devices, there is generally a method for the user to periodically switch to storage battery operation and discharge the storage battery to check, but this is often not carried out because it is time-consuming and There is a problem in that the discharge operation affects the life of the storage battery.

[0006]Also, a method has been proposed in which the device is set in a test mode, the storage battery is discharged with an actual load connected to it, and the tendency of the storage battery voltage to decrease at that time is detected. A discharge operation is required for the test, which affects the life of the storage battery, and there remains the problem that it is necessary to actually apply a load, causing inconvenience and difficulty in test operation.

[0007]Furthermore, depending on how the device is used, it may not be possible to properly detect the condition, and in particular, in the case of a device using a completely sealed sealed storage battery, the internal condition of the storage battery cannot be inspected. It is very difficult to detect the deterioration state of storage batteries.

Therefore, in order to solve the above problem, the present invention uses a storage battery that can automatically detect the state of the storage battery without any effort on the part of the user, and without affecting the life of the storage battery due to discharge of the storage battery. The purpose is to provide electronic devices with improved performance.

[0009]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides an electronic device using a storage battery that is charged with current from an external power source, including charging voltage control means for controlling the charging voltage of the storage battery; Charging voltage instructing means for instructing the charging voltage control means to sequentially apply a charging voltage lower than the appropriate charging voltage of the storage battery, the appropriate charging voltage, and a charging voltage higher than the appropriate charging voltage to the storage battery; , charging current detection means for detecting a charging current value or a rate of change in the charging current value when the charging voltage control means sequentially applies the charging voltage to the storage battery according to instructions from the charging voltage instruction means; The present invention is characterized by comprising state determining means for determining the state of the storage battery based on the charging current value from the means or the rate of change in the charging current value.

0010

[Operation] In the present invention, the charging voltage instructing means sequentially applies a charging voltage lower than the appropriate charging voltage of the storage battery, the above-mentioned appropriate charging voltage, and a charging voltage higher than the above-mentioned appropriate charging voltage to the storage battery, to the charging voltage control means. According to the instruction, the charging voltage control means sequentially applies a charging voltage to the storage battery, and the charging current detecting means detects the charging current value or its rate of change at that time. Then, the state determining means determines the state of the storage battery based on the charging current value or the rate of change thereof from the charging current value detecting means. Therefore, when determining the state of the storage battery, there is no need to perform discharging.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an uninterruptible power supply (UPS) as an electronic device using a storage battery according to the present invention will be described below with reference to the drawings. In this example, the rectifier circuit, DC-AC inverter, storage battery, and output switching relay are the same as the conventional one shown in FIG. Uses storage batteries.

FIG. 1 shows the configuration of this embodiment as a block diagram, and the device of this embodiment includes a rectifier circuit 1, a DC-A
In addition to the C inverter 2, the storage battery 4, and the output switching relay 5, there is also a UPS control circuit 11, a charging voltage indicating circuit 12, a charging circuit 13, a current detection sensor 14, and a charging current discrimination circuit 1.
5, and an alarm circuit 16.

The UPS control circuit 11 is a circuit that controls the operation sequence of this device, and upon startup of the device or upon receiving a storage battery check command from an operator's operation of an external switch (not shown), the UPS control circuit 11 outputs a storage battery to the charging voltage indicating circuit 12. A check mode start signal 11a is output. Further, the UPS control circuit 11 receives a discrimination signal 15a for each check step from the charging current discrimination circuit 15, and sends an alarm output instruction signal 11b to the alarm circuit 16 based on the result. Note that this UPS control circuit 11 may use a CPU, and the CPU may operate as described above under program control.

The charging voltage indicating circuit 12 is the UPS control circuit 1.
1 receives the storage battery check mode start signal 11a from 1,
Check operation control of the storage battery 4 for the charging circuit 13, that is, three types of charging voltage switching signals 12a, 12b, 12c
are output in each of three check steps, and in each check step, an instruction is given to apply a charging voltage according to each signal 12a, 12b, and 12c to the storage battery 4, and a relay control signal 12d is output to control the output switching relay. The output switching relay 5 is turned off to prevent the storage battery 4 from being discharged while the storage battery 4 is being charged and in the check mode.

Here, the charging voltage that the charging voltage instructing circuit 12 instructs the charging circuit 13 through the charging voltage switching signals 12a, 12b, and 12c is a charging voltage VB1 lower than the appropriate charging voltage VB2 of the storage battery 4, and a charging voltage VB1, which is lower than the appropriate charging voltage VB2 of the storage battery 4, respectively. Voltage V
B2, the charging voltage VB3 is higher than the appropriate charging voltage VB2. In this embodiment, for example, the appropriate charging voltage VB2 is set to about 2
．． 2 [V/cell] (see FIG. 2), charging voltages VB1 and VB3 are respectively VB1=2.0 [V/cell] VB3=2.8 to 3.0 [V/cell]. Note that the appropriate charging voltage is a voltage required to normally charge the storage battery 4 specified by the storage battery manufacturer.

In addition, the charging circuit 13 normally rectifies the current from the commercial power source and charges the storage battery 4 at the appropriate charging voltage VB2 of the storage battery 4, while in the storage battery check mode, the charging circuit 13 rectifies the current from the commercial power source and charges the storage battery 4 at the appropriate charging voltage VB2. The charging voltages VB1, VB2, and VB3 set in advance according to the charging voltage switching signals 12a, 12b, and 12c are output.

The current detection sensor 14 detects the value of the charging current iB supplied from the charging circuit 13 to the storage battery 4.

The charging current discrimination circuit 15 is connected to the current detection sensor 1
Input the value of the charging current iB detected by 4 at each check step, compare that value with a preset reference value,
The comparison result is sent to a judgment signal 15a for each check step.
It is output to the UPS control circuit 11 as a. Note that the determination method based on the reference value and the comparison with the reference value is determined based on the characteristics of the charging current with respect to the charging applied voltage in the normal state, over-discharge state, and deteriorated state of the storage battery shown in FIG.

FIG. 2 shows the normal state, over-discharge state, and
and shows an example of characteristics of charging current with respect to applied charging voltage in a degraded state. From this figure, it can be seen that the following characteristic differences can be seen in the charging current characteristics of a storage battery in a normal state, a storage battery in an overdischarged state, and a storage battery that has completely deteriorated and entered a high impedance state.

(1) Storage battery in normal state (curve 2 in Figure 2)
a to 2d, 3a) Curve 2a is a fully discharged state, 2b to 2d is a charging state (
Of these, 2d shows the characteristics of the storage battery in the almost fully charged state), and 3a shows the characteristics of the storage battery in the fully charged state.

[0021] In the storage battery in these conditions, the charging current rises sharply from the point at which the charging voltage exceeds the open terminal voltage of the storage battery, and the charging current rises sharply to a value of 2.0 [V/cell] lower than point A indicating the appropriate charging voltage VB2. At charging voltage VB1, almost no current flows.

In other words, when charging is completed with the proper charging voltage VB2 applied, the charging current becomes an extremely small value as at point 6a on curve 2d or point 6b on curve 3a, but if the charging voltage is further increased When it increases, the charging current rises rapidly. For example, when the applied voltage is increased to 3.0 [V/cell] from a state where charging is completed at an appropriate voltage (point 6b on curve 3a), the charging current increases rapidly to point 6c. In addition, in the figure, 0%, 60%, 80%, 90%, 100
% indicates the charging rate of the storage battery.

(2) Storage battery in overdischarge state (curves 4a to 4e in FIG. 2)
Curves 4a to 4e indicate the terminal voltage drop of the storage battery and no deterioration (
This shows an over-discharge state which is a state (not completely degraded), and shows that the degree of over-discharge progresses as it goes from 4a to 4b to 4c to 4d to 4e. In addition, in the figure, the broken line shows the process from the over-discharged state to the deteriorated state of the storage battery.

From this figure, 4a→4b→4c→4d→4
As the overdischarge progresses to e, the open terminal voltage increases to 7a→
7b → 7c → 7d, the voltage decreases below point AA indicating the appropriate charging voltage VB2, and finally reaches 0 at point 7d.
It can be seen that the voltage has decreased to [V].

Furthermore, since a drop in the open terminal voltage is observed due to overdischarge, the charging voltage begins to flow from the point where it exceeds this open terminal voltage. A charging current begins to flow, and it can be seen that even at a charging voltage VB1 of 2.0 [V/cell], which is lower than the appropriate charging voltage VB2, a current is flowing, unlike a storage battery in a normal state. In other words, in curve 4a, the charging current begins to flow from a point exceeding the voltage of point 7a, in curve 4b, the voltage exceeds point 7b, and in curves 4d and 4e, the charging current starts flowing from a point above point 7d, and the charging voltage continues to flow until complete deterioration occurs. The charging current increases with the increase.

(3) Storage battery in a degraded (completely degraded) state (curve 5a in FIG. 2) The curve 5a shows the completely degraded state of the storage battery. In this state, the suitable charging voltage VB2 and the higher approximately 2
．． It can be seen that even when a charging voltage VB3 of 8 to 3.0 [V/cell] is applied, almost no charging current flows and the storage battery does not recover.

Utilizing the above characteristic differences, in this embodiment, deterioration or abnormality of the storage battery is detected by controlling the charging voltage and detecting the state of the charging current at that time. Note that the time required for detection may be about several tens of seconds.

FIG. 3 shows the sequence of charging voltage application in the storage battery check mode by this device. In other words,
As shown in the figure, this device applies a charging voltage VB1 lower than the appropriate charging voltage in the first check step 1, then applies an appropriate charging voltage VB2 in check step 2, and a charging voltage VB3 higher than the appropriate charging voltage in check step 3. After the check step 3 is completed, the normal charging operation is performed, so the appropriate charging voltage VB2 is applied.

Next, referring to FIG. 4, the storage battery checking operation by this device will be explained.

FIG. 4 is a flowchart showing the processing of this apparatus in the storage battery check mode. In addition,
In the figure, IB is the value of charging current iB, n is a coefficient, C is a constant indicating the battery rated capacity, and n·C is a reference value. For the reference value n・C, select a value that is slightly larger than the charging current value when the storage battery 4 is normal, under the application of the appropriate charging voltage VB2, and in the fully charged state (see curve 3a in FIG. 2). In this example, a lead-acid battery is used as the storage battery 4, so if n is normally chosen to be around 0.025, it will be 2.2 [Ah].
In a lead-acid battery with a rated capacity of , n·C is approximately 50 [mA].

In the storage battery check mode, as shown in FIG. 1, the storage battery check command is issued by operating an external switch or the like.
The battery check mode start signal 11a from the UPS control circuit 11 enters the PS control circuit 11, and the battery check mode start signal 11a is sent to the charging voltage instruction circuit 1.
2, the charging voltage indication circuit 12
Each check step 1 to 3 is sequentially executed by charging voltage switching signals 12a, 12b, and 12c from.

First, in the first check step 1, the charging circuit 13 applies a voltage of approximately 2.0 [V/cell] to the storage battery 4 according to the charging voltage switching signal 12a from the charging voltage indicating circuit 12.
A charging voltage VB1 lower than the appropriate charging voltage VB2 is applied (step 100), the current detection sensor 14 checks the charging current value IB at this time (step 200), and the charging current value IB and the reference value n・C are Charging current discrimination circuit 1
5 compares (step 300).

As a result, the charging current value IB is equal to the reference value n·C.
If it is larger (step 300 "No"), it can be determined that the charging current iB has flowed due to the application of the charging voltage VB1 lower than the appropriate charging voltage VB2, so this state corresponds to curves 4a to 4e in FIG. Charging current discrimination circuit 1
In step 5, it is determined that the terminal voltage of the storage battery 4 has abnormally decreased due to an overdischarge state or a cell short circuit (step 350).
).

On the other hand, if the charging current value IB is smaller than the reference value n·C (step 300 "Yes"), the charging voltage switching signal 12b from the charging voltage indicating circuit 12 moves to the next check step 2, The charging circuit 13 then applies the appropriate charging voltage VB2 to the storage battery 4 (step 40).
0), the charging current value IB at this time is checked (step 500), and the charging current value IB is compared with a reference value n·C (step 600).

As a result, the charging current value IB is equal to the reference value n·C.
If it is larger (step 600 "No"), it can be determined that the charging current iB has flowed due to the application of the appropriate charging voltage VB2, and this state corresponds to curves 2a to 2c in FIG.
Corresponding to this, the charging current determining circuit 15 determines that the storage battery 4 is in a normal state and is being charged (step 650).

On the other hand, if the charging current value IB is smaller than the reference value n·C (step 600 "Yes"), the charging voltage switching signal 12c from the charging voltage instruction circuit 12 causes the process to proceed to the final check step 3. The charging circuit 13 has a voltage higher than the appropriate charging voltage VB2 of 2.8 to 3.0 [V/
A charging voltage VB3 of the cell] is applied to the storage battery 4 (step 700), and a charging current value IB at this time is checked (
Step 800), this charging current value IB and the reference value n・C
(step 900).

As a result, the charging current value IB is equal to the reference value n·C.
If it is larger (step 900 "No"), a charging current iB larger than the reference value n.C does not flow when the appropriate charging voltage VB2 is applied, and a charging current iB larger than the reference value n.C does not flow when the charging voltage VB3 is higher than the appropriate charging voltage VB2. Large charging current iB
It can be determined that the flow has occurred, so this state corresponds to curve 2 in Figure 2.
d or 3a, and the charging current determining circuit 15 determines that the storage battery 4 is in a normal state and charging is almost completed (step 950).

On the other hand, if the charging current value IB is smaller than the reference value n·C (step 600 “Yes”), the charging current iB remains at the reference value n·C even if a charging voltage VB3 higher than the appropriate charging voltage VB2 is applied. Since it can be determined that the current is not flowing as much as C, this is the state of the curve 5a in FIG.
0).

The storage battery check mode operation is thus completed, and the output voltage of the charging circuit 13 shifts to the normal charging voltage state as shown in FIG. 3 as well.

In this storage battery check mode, a determination signal 15a is input from the charging current determination circuit 15 to the UPS control circuit 11 at each check step 1 to 3, and the UPS control circuit 11 receives the determination signal 15a. For example, the charging current discriminating circuit 15
When it is determined in steps 350, 950, and 1000 that the storage battery 4 is over-discharged, charging is completed, abnormality, etc., it sends an alarm output command 11b to the alarm circuit 16 to detect over-discharge, charging completion, abnormality, etc. generates an alarm indicating the

Therefore, according to this embodiment, the charging voltage of the storage battery 4 is controlled in stages, the charging current value at this time is detected, and this charging current value and the charging/discharging state and deterioration state of the storage battery 4 are characterized. Since the state of the storage battery 4 is determined based on the charging current and voltage characteristics that appear as a difference in the battery voltage, the battery 4 can be discharged in a short period of time and automatically, without having to discharge the battery and having a negative effect on the battery life, and without any manual intervention. It is possible to detect storage battery deterioration, charging failure, etc.

[0042] In the above embodiment, the case of a lead-acid battery was explained, but the present invention can also be applied to other types of secondary batteries such as a nickel-cadmium battery.

Further, in the above embodiment, an uninterruptible power supply device is explained in which a storage battery is used as an auxiliary power source and current is supplied from the storage battery in the event of a power outage. It is not limited to devices, but includes electronic devices such as computers that normally use current from a main power source such as a commercial power source, and use storage batteries as an auxiliary power source during a power outage, and electronic devices that use storage batteries as their main power source. Applicable to equipment.

Further, in this embodiment, the charging voltage of the storage battery is increased stepwise in the storage battery check mode, but in the present invention, it may be increased continuously.

In this case, in addition to the method of detecting and comparing charging current values as described in this embodiment, changes in the rate of increase in charging current value with respect to a constant voltage change width near the charging voltage level in each check step may be used. It is also possible to detect the rate of change and determine the state of the storage battery based on the rate of change. That is, as is clear from the charging characteristics of the lead-acid battery shown in FIG. 2, when the rate of change in the charging current value is the largest in each check step of applying charging voltages VB1, VB2, and VB3, in FIG. Curves 2a to 2d and 3a are normal conditions, then curve 4a when the rate of change in charging current value is large.
~4e overdischarge state, the rate of change in charging current value is almost 0
The state of the storage battery can be determined by range based on the magnitude of the rate of change in the charging current value, such as a complete deterioration state as shown by the curve 5a when it is close to .

[0046]

As explained above, in the present invention, a voltage lower than the appropriate charging voltage of the storage battery, a suitable charging voltage, and a voltage higher than the suitable charging voltage are sequentially applied to the storage battery.
At that time, the charging current value or its rate of change supplied to the storage battery is detected, and the state of the storage battery is determined based on the charging current value or its rate of change. It is possible to determine the state of charge and abnormal conditions such as over-discharge and deterioration.

Therefore, in electronic devices that use storage batteries, the discharge operation does not adversely affect the life of the storage battery, and it is possible to automatically detect storage battery deterioration, charging failure, etc. without human intervention, and to detect storage battery defects. It is possible to prevent unexpected operation stoppage of equipment due to

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of an uninterruptible power supply device as an electronic device using a storage battery according to the present invention.

FIG. 2 is a characteristic diagram showing charging characteristics of a lead-acid battery.

FIG. 3 is an explanatory diagram showing an operation sequence in a storage battery check mode in this embodiment.

FIG. 4 is a flowchart showing processing in a power storage check mode according to the present embodiment.

FIG. 5 is a block diagram showing an example of an electronic device using a conventional storage battery.

[Explanation of symbols]

1 Rectifier circuit 2 DC-AC inverter circuit 4 Storage battery 5 Output switching relay 11 UPS control circuit

Claims (1)

[Claims] 1. In an electronic device using a storage battery that is charged with current from an external power source, charging voltage control means for controlling the charging voltage of the storage battery, and charging voltage control means that sequentially performs appropriate charging of the storage battery. Charging voltage lower than the voltage,
A charging voltage instructing means instructs to apply the appropriate charging voltage and a charging voltage higher than the appropriate charging voltage to the storage battery, and the charging voltage control means sequentially adjusts the charging voltage to the A charging current detection means for detecting a charging current value or a rate of change in the charging current value when applied to the storage battery, and a state of the storage battery based on the charging current value or the rate of change in the charging current value from the charging current detection means. An electronic device using a storage battery, characterized by comprising: a state determining means for determining the state.