JPH0894726A - Battery capacity detection device - Google Patents

Abstract

PURPOSE: To provide a battery capacity detection device for properly judging and displaying the remainder of a battery in use. CONSTITUTION: A battery 1 is constituted so that it can be replaced by a new one, a replacement switch 5 with a battery with a battery contact piece 4 detects battery replacement, a thermometer 7 for automatically selecting characteristics via an FF6 when the replacement is completed measures the temperature of the battely 1, one axis of a storage part 9 is addressed via an A/D converter 8 and a target to be read and written of the storage part 9 is changed according to the battery characteristics to be changed according to temperature. An A/D converter 10 converts the terminal voltage of the battery 1, latches a voltage on open-circuiting by a latch circuit 11, addresses one axis of the srorage part 9, and then changes the target to be read and written of the storage part 9. A selection switch 12 is used to select read address and a display 13 displays the open-circuiting voltage value and a storage value at each temperature according to the selected battely type.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery capacity detecting device for intermittently charging or discharging a battery.

[0002]

2. Description of the Related Art A battery has different characteristics depending on the operating temperature and the type of the battery. When using, it is necessary to operate the device within the proper charge / discharge characteristics. Therefore, as is clear from JP-A-5-87897 (Casio Computer Co., Ltd.), the characteristic table of a predetermined battery is switched depending on the temperature, and the remaining operation (dischargeable) time is displayed to the user (even if It is configured so that proper use / replacement / charging decisions can be made even in extremely cold places.

Further, in a device in which both a secondary battery and a primary battery can be used, the charging point and the operation prohibiting voltage can be switched by changing the connection point between the two and a switch that operates according to the shape of the battery pack. The example configured in
It was found in M. THINKPAD 220 etc.

[0004]

However, in the above-mentioned conventional example, it is not possible to deal with batteries having the same shape and different characteristics, and it is not possible to deal with batteries having characteristic changes such as memory effect. There was a drawback that the battery could be exhausted during operation and the necessary charging could be erroneously determined without indicating the available time. Depending on the structure of the battery itself, the characteristics are quite different, such as manganese battery and alkaline manganese battery, and the recently announced lithium ion secondary battery, and the voltage is also different, such as AA-shaped 3V lithium ion primary battery. Exists.

When these batteries are used intentionally or negligently, proper judgment and display corresponding to them are not performed, and it is judged that the remaining amount is low during operation, and the battery is interrupted.
There is a defect that an abnormal state may be reached without judgment or excessive charging may occur.

The present invention has been made in order to solve such a conventional problem, and an object of the present invention is to provide a battery capacity detection device capable of appropriately determining and displaying the remaining capacity of a battery in use.

[0007]

In order to achieve the above object, the battery capacity detecting device of the present invention is provided with an internal resistance of a battery,
It has a measurement unit for other dynamic characteristics, a measurement unit for load voltage, closed circuit voltage, and other static characteristics, and a storage unit for storing a plurality of battery characteristics, and measurement and temperature measurement at each of the above measurement units. According to this, one of the characteristics of each connected battery is automatically selected, and means for displaying the remaining capacity value of the battery and means for performing charge / discharge control are provided based on the selected characteristics. Is.

[0008]

[Function] With the above configuration, various battery characteristics are stored,
It is possible to display according to them, to indicate the current state within the first memory selected characteristics by open or predetermined load closed circuit voltage measurement, and more accurately to measure the memory and battery characteristics by temperature measurement. The battery characteristics automatically based on the measured value and the first stored value obtained by the impedance and internal resistance measuring means by dynamic measurement such as open-circuit potential and predetermined closed-circuit potential or closed-circuit current value and potential difference or AC impedance. By providing a part that matches data similar to
The matching operation of the automatic selection is controlled so that the initial automatic selection such as battery attachment / detachment and the limited automatic selection again when the battery gradually deteriorates can be handled.

[0009]

【Example】

[First Embodiment] FIG. 1 is an overall view of the present invention, in which a battery 1 is configured to be discharged from a discharge terminal 2 and charged from a charge terminal 3 as needed. The battery 1 is configured to be replaceable in some cases, and a replacement switch 5 having a battery contact piece 4 for that purpose is a switch for detecting battery replacement, and when the replacement is completed, automatic characteristic selection is performed via a flip-flop (hereinafter abbreviated as FF) 6. Let it be done. 7 is a thermometer for measuring the temperature of the battery 1,
According to the battery characteristics that change with temperature, one axis of the storage unit 9 is addressed through the A / D converter 8 to change the read / write contrast (position) of the storage unit 9. A / D converter 10
Converts the terminal voltage of the battery 1 and latches the open circuit voltage by the latch circuit 11 to address one axis of the storage unit 9 to change the read / write contrast (position) of the storage unit 9. 1
A read address selection switch 2 is used to select a similar one from the stored various characteristics. As a general display, there is a capacity% or a remaining capacity value, and this display by the display 13 is displayed as a stored value at an open circuit voltage value and a temperature according to the selected battery type.

The flow of this data is described in JP-A-45-878.
It can be said that it is similar to that disclosed in No. 97. The feature of the present invention is that if the intermittent timer output of 14 and the current measurement value by the resistor 15 and the differential amplifier 16 change, the logical sum of the output of the change detector 17 composed of a high pass filter is regenerated by the OR gate 18. The measurement is performed, and the display on the display 13 is renewed and the characteristics are reviewed. For example, in the case of an internal resistance, the open circuit voltage stored in the latch 11 and the voltage drop value information obtained by the difference calculator 19 are used as the power source for A / D.
According to the information converted by the converter 20, the divider 21 is used for division, and the averaging calculator 22 is used to remove pulse errors and read / write (R / W) available area 2 in the storage unit 9.
It is stored in 3 as current address (state) data.

An internal resistance value and a capacitance value are stored in a pair in the ROM of the storage unit 19, the selected capacitance value is displayed as described above, and the difference between the reference internal resistance value and the measured resistance value is calculated by a calculator. 24, the comparator 25 detects a case where the characteristic difference is extreme, and operates the selection counter 27 with the signal passed through the OR gate 26 (when the characteristic difference is excessive or the battery is replaced) to select similar characteristic data. I am trying. By assigning a specific bit to this capacity data, if the value less than the predetermined value is zero and the value more than the predetermined value is too large, it is possible to perform charge / discharge control according to the selected data, that is, according to the battery characteristics. Discharging is prohibited with the switch 31 in FIG. 3, or vice versa.
2 can prohibit charging and prevent overcharging.

FIG. 2 shows zeros of a certain kind of storage unit 9 at a certain temperature, which includes voltage, internal resistance, capacity, discharge possibility,
It is memorized like whether it can be charged or not and is addressed in terms of voltage. The battery is compared with the actual battery in terms of internal resistance at each voltage, and is compared with a different type battery when it is extremely deviated as described above. The capacity term is used in the above-mentioned display, and the discharge possibility is controlled by closing and opening the discharge switch 31 in FIG. 3 according to the possibility signal to prevent over-discharge. In addition, the charge availability item controls the charging switch 32 of FIG. 3 by opening and closing according to the enable / disable signal to prevent overcharging and erroneous charging of the primary battery. 33 indicates an error in charging polarity. It is a diode to prevent.

In an actual battery, there is an example in which the configuration is reversed when the open circuit potential does not change much. That is, a predetermined load 35 is applied by the switch 34 of FIG. 3, the voltage at that time is held by the latch 11 of FIG. 1 and used as the address of the storage unit 9, and the internal resistance is calculated from the difference between no load or actual load. Is the way.

Also, the switch 34 is used without using the internal resistance value.
A method of performing A / D conversion by the A / D converter 10 in synchronism with the opening and closing of and then omitting the current calculation by using the voltage difference may be used. However, in that case, since the charge / discharge current needs to be stable as in the example, if the power supply may be temporarily stopped by the load device, the switch 31 is opened to measure, or the charge / discharge current is measured by current measurement. It is necessary to make a sequence so that measurement is performed when there is no time.

Now, there are batteries having various characteristics. In FIG. 4, for example, when voltage vs. life at a predetermined load is plotted, the voltage of a general battery gradually decreases as a characteristic curve 40 in the figure, but the capacity of a high performance battery as a characteristic curve 41 is large. , The voltage drops slowly, and the internal capacity of the battery has decreased due to high temperature storage etc.
It shows the characteristic that the potential suddenly drops. Further, some batteries having different polar materials, such as 43, exhibit flat voltage characteristics and a sharp voltage drop at the end stage.

In a relatively heavy load, the voltage-current characteristic under load influences the operation. For this purpose, the voltage at a medium load and the current that can be taken out, that is, the internal resistance are important factors. Therefore, by transmitting the internal resistance information to the load, it is possible to more accurately determine whether or not a series of load actions can be performed.

Batteries are left for a long time or fail to charge (over discharge,
The characteristics may change due to overcharging).
The characteristics of 0 to 42 may change, but the characteristic curve 4
It does not change like 3. Therefore, characteristic curves 40 to 42
Groups and groups such as the characteristic curve 43 are divided and stored, and the characteristic curves 41 → 40 → 42 in the group are stored.
Such a unidirectional automatic change is relatively easily performed by increasing the in-digit count of the counter 27 at the request of the window comparator 25.
However, the search outside the group is after the change of the exchange switch 5,
That is, only while the FF 6 is holding, the extra digits and the circulation of the counter 27 are permitted and the search including the battery type is performed.

For example, in the case of a secondary battery, characteristic curve 4 before deterioration
1 allows a little overcharging and overdischarging, but the characteristic curve 42 after deterioration limits the switches 31 and 32 so that they are used gently so that they do not charge much and do not discharge much. It is configured to notify the person of deterioration.

[0019]

As described above, according to the present invention,
Even if various batteries are used, the battery type can be automatically determined, and appropriate capacity display and charge / discharge control can be performed. In particular, appropriate (adapted) use, display, and charge / discharge control can be performed on a secondary battery that is prone to memory effects, deterioration due to overcharge, deterioration due to overdischarge, and the like. Since the measurement is also triggered by a large current change, there is an advantage that the detailed measurement can be performed only when the battery characteristic can be changed.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an overall configuration of an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an example of a storage unit of the embodiment of FIG.

FIG. 3 is an explanatory diagram showing an example of charge / discharge control of the embodiment of FIG.

FIG. 4 is a diagram illustrating a characteristic example of each battery.

[Explanation of symbols]

 1 Battery 4 Battery Contact 5 Exchange Switch 6 Flip-Flop (FF) 7 Thermometer 8, 10 A / D Converter 9 Storage Section 11 Latch Circuit 12 Selection Switch 13 Display Section 14 Timer 17 Change Detector 21 Divider 22 Average Calculation Instrument 27 Characteristic selection counter

Claims (1)

[Claims] 1. A measuring unit for measuring internal resistance of a battery and other dynamic characteristics, a measuring unit for measuring load voltage, closed circuit voltage and other static characteristics, and a storage unit for storing a plurality of battery characteristics. By the measurement and temperature measurement in each of the measurement unit, one of the characteristics of each battery connected is automatically selected, based on the selected characteristics, means for displaying the remaining capacity value of the battery, and A battery capacity detecting device comprising means for performing charge / discharge control.