JPH07326392A - Charging device - Google Patents

Abstract

PURPOSE:To provide a charging device having the capability of ensuring a secondary battery to be charged up to fully charged state. CONSTITUTION:A secondary battery 2 is charged through a charging section 11 and the voltage value of the battery 2 at a charging process is detected at the prescribed cycle. Also, the mean value of voltage values detected at every prescribed cycle is computed. Then, the latest computed mean value and the mean value computed immediately previously are compared with each other. In this case, the battery 2 is judged to be in fully charged state, when a difference between both mean values is found to be within the prescribed range. When the difference is beyond the scope of the range, the battery 2 is judged to be under voltage fluctuation, due to a heavy load, and this state is neglected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging device for charging a secondary battery used in a cordless telephone or the like.

[0002]

2. Description of the Related Art A telephone or the like which uses a secondary battery such as a cordless telephone is usually provided with a charging device for charging the secondary battery. When the secondary battery is charged in this charging device, the terminal voltage Vc thereof gradually rises to the full charge state as shown in FIG. 4 and drops by about -Δt when reaching the maximum value in the full charge state. Are known.

Now, during charging of the secondary battery, a heavy load may be applied to the secondary battery itself due to various circumstances (for example, an incoming call during charging in a telephone). In this case, the terminal voltage Vc of the secondary battery causes a momentary intermittent voltage drop as indicated by 51 in FIG. In most cases, this is a pulse load as shown in FIG.

[0004]

However, when the instantaneous and extreme voltage drop occurs as described above, the terminal voltage Vc of the conventional charging device drops after reaching the maximum value in the fully charged state. Therefore, it is erroneously recognized that the battery is already in the fully charged state before the original fully charged state.

In the above-mentioned case, even if the secondary battery is charged in the charging device, the charging is stopped before the fully charged state, and the original purpose of using the charging device is sufficiently achieved. Therefore, the need for a charging device that can reliably charge the battery to the fully charged state has arisen. The present invention has been made in view of the above circumstances, and an object thereof is to provide a charging device that can reliably charge a secondary battery to a fully charged state.

[0006]

SUMMARY OF THE INVENTION The present invention includes a charging means for charging a secondary battery, a voltage detecting means for detecting a voltage value of the secondary battery being charged by the charging means at a predetermined cycle, and An average value calculating means for calculating an average value of voltage values for each predetermined period among the voltage values detected by the voltage detecting means, and an average for comparing the average value calculated by the average value calculating means with the previously calculated average value. It comprises a value comparison means and a full charge state determination means for determining a full charge state when the difference between the average values is within a predetermined range based on the comparison result by the average value comparison means, and for determining otherwise that it is not full charge. There is.

According to the present invention, when the difference between the average values as the comparison result of the average value comparing means exceeds a predetermined range, the average value calculating means determines a predetermined voltage value among the voltage values detected in the predetermined period this time. Calculate the average value for the next comparison except for the following: The present invention comprises a charging status output means for outputting the charging status detected by the voltage detecting means and the full charging status determining means.

[0008]

According to the present invention, the secondary battery is charged, the voltage value of the secondary battery being charged is detected at a predetermined cycle, and the average value of the detected voltage value for each predetermined period is calculated. , The average value and the previously calculated average value are compared, and from the comparison result, when the difference between the average values is within a predetermined range, it is determined that the battery is in a fully charged state, and other than that, it is determined that the battery is not fully charged. Even if a heavy load is applied during charging of the secondary battery, the full-charged state will not be erroneously recognized.

According to the present invention, in the calculation of the average value described above, when the difference between the average values which is the comparison result of the average values exceeds the predetermined range, the predetermined voltage among the voltage values detected in the predetermined period this time is determined. Since the average value for the next comparison is calculated excluding those less than or equal to the value, even if there is a heavy load during charging of the secondary battery, the average value of the appropriate voltage values can be calculated and full charge is performed. No more erroneous recognition of status.

Since the present invention outputs the detected charging status and full charging status, the user of the charging device can know the charging status of the secondary battery and whether or not it is fully charged. it can.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of a charging device in this embodiment. In FIG. 1, reference numeral 1 denotes a charging device according to the present invention, 2 denotes a secondary battery, and the charging device 1 has an output terminal a having a positive electrode terminal of the secondary battery 2 and an output terminal b having a negative electrode terminal of the secondary battery 2, respectively. Connected. This secondary battery 2 is
It is a power source for a load 3 such as a telephone.

At the output terminals a and b of the charging device 1,
The charging unit 11, the voltage detection unit 12, the control unit 13, and the display unit 14 are connected. Here, the charging unit 11 is the secondary battery 2
Then, the voltage detector 12 detects the terminal voltage of the secondary battery 2 charged by the charger 11. Then, the control unit 13 performs overall operation control of the charging device 1, and the display unit 14 outputs the charging process, notification of a fully charged state, and the like.

Further, a storage unit 15 is connected to the control unit 13, and the storage unit 15 has a cycle for detecting the voltage of the secondary battery 2 in the voltage detection unit 12 and an average value of the voltages to be described later. Each of the information, such as the detection period and the predetermined range of the average value difference of the voltage for detecting the fully charged state, is stored. Further, the detected voltage value is sequentially stored in the storage unit 15, and the average value of the calculated voltages during the period is also stored.

Next, according to the flow chart shown in FIG.
The operation procedure of the charging device 1 will be described. It should be noted that the secondary battery in this embodiment is also charged with the voltage characteristic as shown in FIG. 4 described above.

When a heavy load is generated during charging, a pulse waveform is generated in the voltage characteristic curve as shown in FIGS. 5 and 6 as described above. First, the control unit 13 controls the charging unit 1
When 1 is instructed to charge the secondary battery 2, the charging unit 11 starts charging the secondary battery 2 through the output terminals a and b (step s1).

Then, the control unit 13 instructs the voltage detection unit 12 to detect the voltage of the secondary battery 2 every predetermined period t based on the information of the detection period stored in the storage unit 15 in advance.
Then, the voltage detection unit 12 detects the voltage of the secondary battery 2 through the output terminals a and b at every predetermined cycle t, and sequentially notifies the control unit 13 of the detection result through the output terminals a and b. Then, the control unit 13 sequentially stores the notified voltage value in the storage unit 15 (step s2).

Subsequently, the control unit 13 detects whether or not the detection period has elapsed based on the detection period information stored in the storage unit 15 in advance (step s3), and the voltage is detected until the detection period elapses. The detection of the voltage of the secondary battery 2 in the detection unit 12 is continued.

When the detection period elapses, the control unit 13 calculates the average value Va from the voltage values stored in the storage unit 15 and displays the charging status on the basis of the stored voltage values. (Step s4).

Subsequently, the magnitude relationship between the calculated average value Va and the previous average value stored in the storage unit 15 is compared. Here, if the current average value is equal to or higher than the previous average value (step s5), it means that the voltage value is increasing, and since the normal charging is continued, the storage unit 15 stores it. The previously stored average value is rewritten and stored as the current average value (step s9), and the voltage detection unit 12 again detects the voltage (step s2).

On the other hand, when the current average value is smaller than the previous average value (step s5), the difference between the average values is stored in the storage unit 1.
5 is determined based on the predetermined range information of the average value difference for detecting the fully charged state, and if the average value difference is within the predetermined range (step s6), the rechargeable battery 2 is charged. It is considered that a voltage drop has occurred due to the fully charged state, and the fact that the fully charged state is reached is output to the display unit 14 (step s10), and the trickle charging for preventing the charging by the charging unit 11 from discharging with a small current Switch to.

When the difference between the average values is not within the predetermined range (step s6) and is larger than the predetermined range (step s7), the voltage value detected during the predetermined period is different from the previous average value. Those in which the difference exceeds a certain value, for example, in FIG.
When the predetermined period is set to t1 to t8, Vb at t4 and t8 is deleted (step s8), and the average value is calculated again (step s4).

Here, when the difference between the average values is not larger than the predetermined range (step s7), since the normal charging is continued, the previous average value stored in the storage unit 15 is set as the current average value. The average value is rewritten and stored (step s
9) Then, the voltage detection unit 12 detects the voltage again (step s2).

Since the predetermined range in which the heavy load is considered to be generated varies depending on the type of secondary battery and the number of cells, it is necessary to grasp the characteristics of the secondary battery to be charged. For example, in the case of 1 cell, −Δ in FIG. 4 is −4 m
When V is considered to have passed full charge, the predetermined range in which a heavy load is considered to occur is -4 mV to -15 mV due to the various factors described above. Similarly, 3
In the case of cell series connection, it is determined in consideration of the internal resistance of the secondary battery, such as -12 mV to -50 mV.

Therefore, according to such an embodiment, the secondary battery 2 is charged by the charging unit 11, the voltage value of the secondary battery 2 being charged is detected at a predetermined cycle, and the detected voltage value is detected. The average value for each predetermined period is calculated, the calculated average value is compared with the previously calculated average value, and if the difference between the average values is within a predetermined range from the comparison result, it is determined that the battery is fully charged. However, other than that, since it is determined that the voltage fluctuation is due to heavy load and is ignored, even if there is a heavy load during charging of the secondary battery 2, the full charge state is not erroneously recognized. At the same time, the user can know the charging status of the secondary battery and whether or not it is fully charged, which can prevent malfunction and ensure that the device is fully charged until it is fully charged. It can be effectively used as a charging device.

The present invention is not limited to the above-described embodiments, but can be modified and implemented as appropriate without departing from the scope of the invention.
For example, the predetermined range that is considered to have caused a heavy load is
The type and the number of cells of the secondary battery to be charged, the characteristics of the secondary battery, etc. are taken into consideration and appropriately set.

[0026]

According to the present invention, the secondary battery is charged, the voltage value of the secondary battery being charged is detected in a predetermined cycle, and the average value of the detected voltage values for each predetermined period is calculated. Calculated and compared the average value with the previously calculated average value, and from the comparison result, if the difference between the average values is within a predetermined range, it is determined to be a fully charged state, and other than that it is determined not to be fully charged. Therefore, even if there is a heavy load during charging of the secondary battery, the full-charge state will not be erroneously recognized, which prevents malfunction due to erroneous recognition of the full-charge state due to heavy load during charging, It can be reliably charged to the fully charged state and can be effectively used as a charging device for devices that operate during charging.

According to the present invention, in the calculation of the above-mentioned average value, when the difference between the average values, which is the comparison result of the above-mentioned average values, exceeds a predetermined range, the predetermined voltage among the voltage values detected in the predetermined period this time is determined. Since the average value for the next comparison is calculated excluding those less than or equal to the value, even if there is a heavy load during charging of the secondary battery, the average value of the appropriate voltage values can be calculated and full charge is performed. The device does not erroneously recognize the status, which prevents erroneous operation due to erroneous recognition of the fully charged state due to heavy load during charging, can reliably charge to the fully charged state, and is a charging device for equipment that operates during charging. Can be used effectively.

Since the present invention outputs the detected charging status and full-charged status, the user of the charging device can know the charging status of the secondary battery and whether or not it is fully charged. As a result, it is possible to prevent malfunction due to erroneous recognition of the fully charged state, and it can be effectively used as a charging device for equipment that operates during charging.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of a charging device and a secondary battery according to an embodiment.

FIG. 2 is a flowchart showing an operation procedure of the charging device in the embodiment.

FIG. 3 is a diagram showing a voltage detection situation in one embodiment.

FIG. 4 is a diagram showing a charging situation in one example and a conventional example.

FIG. 5 is a diagram showing a charging situation under heavy load in one example and a conventional example.

FIG. 6 is a diagram showing pulse loads in one example and a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Charging device, 2 ... Secondary battery, 3 ... Load, 11 ... Charging part, 12 ... Voltage detection part, 13 ... Control part, 14 ... Display part,
15 ... Storage unit, a ... Output terminal, b ... Output terminal.

Claims (3)

[Claims] 1. A charging means for charging a secondary battery, a voltage detecting means for detecting a voltage value of the secondary battery being charged by the charging means in a predetermined cycle, and a voltage detected by the voltage detecting means. Among the values, an average value calculating means for calculating an average value of voltage values for each predetermined period, an average value comparing means for comparing the average value calculated by the average value calculating means and the previously calculated average value, the average value A charging device comprising: a full-charge state determination unit that determines that the difference between the average values is within a predetermined range based on the comparison result by the comparison unit, and determines that the other states are not fully charged. 2. The average value calculating means, if the difference between the average values as a comparison result of the average value comparing means exceeds a predetermined range, the average value calculating means determines that the voltage value is equal to or less than a predetermined voltage value among the voltage values detected in the predetermined time period. The charging device according to claim 1, wherein an average value for the next comparison is calculated excluding the ones. 3. The charging device according to claim 1, further comprising a charge status output means for outputting a charge status detected by the voltage detection means and the full charge status determination means.