JPH06123763A - Residual battery capacity monitor - Google Patents

Abstract

PURPOSE:To provide a monitor for residual capacity of battery which can determine residual life of battery an arbitrary point of time during normal use and can display the residual life thus determined. CONSTITUTION:The monitor for residual capacity of battery comprises a switch control means 1c for controlling connection between a battery 2 and a load 3, a voltage measuring means 1a for measuring open circuit voltage and closed circuit voltage of the battery 2 under use in response to switching operation of the switch control means 1c at some point of time, and a decision control means 1b for confirming residual capacity of battery at that point of time based on the difference of voltages thus measured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery remaining capacity monitoring device.

[0002]

2. Description of the Related Art In a conventional battery remaining capacity monitoring circuit used in a battery power supply device or a battery power circuit, an open circuit voltage (OCV) when the battery is unloaded or a closed circuit voltage (CCV) when the battery is loaded. Are measured and monitored, and based on the fact that these voltages decrease as the battery runs out, the closed circuit voltage (C
When at least one of CV) and open-circuit voltage (OCV) has dropped to a preset warning voltage, a dead battery warning is displayed, and when a preset replacement voltage drops, a battery replacement instruction is displayed. It has become.

[0003]

However, in the above-mentioned conventional battery remaining capacity monitoring circuit, the process of gradually decreasing the closed circuit voltage (CCV) or the open circuit voltage (OCV) to the above-mentioned warning voltage or exchange voltage is performed. It had no function to measure and display. Therefore, at the end of the battery capacity, only the notice display and the replacement display are suddenly displayed, and there is no function to judge and display the remaining battery life during normal use. The present invention has been made to solve such a problem, and its purpose is at any point during normal use,
Another object of the present invention is to provide a battery remaining capacity monitoring device capable of determining and displaying the remaining battery life.

[0004]

Due to its characteristics, a battery has an open circuit voltage (OCV) as its capacity decreases and its capacity decreases.
And the closed circuit voltage (CCV) increase. The present invention pays attention to this characteristic and utilizes it. In order to solve the above-mentioned problems, the battery remaining capacity monitoring device according to the present invention is such that the voltage measuring means corresponds to the open / close voltage and the closed circuit of the used battery in response to the opening / closing operation of the switch control means for controlling the connection between the battery and the load. It is characterized in that the voltage is measured, and the determination control means confirms the remaining battery capacity at that time based on the difference between these voltages.

[0005]

When the switch control means cuts off the connection between the battery and the load at a certain point during normal use, the voltage measurement means measures the open circuit voltage (OCV) of the used battery, and the judgment control means receives this. Then, when the switch control means restarts the connection between the battery and the load, the voltage measurement means measures the difference from the closed circuit voltage (CCV) of the used battery, and the judgment control means receives this.

Next, the judgment control means calculates the difference between the received open circuit voltage (OCV) and closed circuit voltage (CCV), and confirms the remaining battery capacity at that time based on this difference in voltage.

[0007]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a functional block diagram of a battery remaining capacity monitoring device according to the present invention. The battery remaining capacity monitoring device 1 includes a voltage measuring unit 1a, a determination control unit 1b, a switch control unit 1c, and a display drive circuit 1d.

The switch control means 1c controls an external switch circuit 4 and opens and closes the switch circuit 4 to open the battery 2
And the connection of the load 3 are controlled. The switch control means 1c operates by the input from the judgment control means 1b.

The voltage measuring means 1a is a voltage measuring circuit 1a1,
It is composed of an AD converter 1a2 and a measurement data capturing means 1a3. The voltage measuring circuit 1a1 measures the battery voltage VB of the battery 2 and inputs a signal to the AD converter 1a2. The measurement data acquisition means 1a3 sends the acquisition timing to the AD converter 1a2, thereby receiving the measurement voltage data sent from the AD converter 1a2 and transferring it to the judgment control means 1b.

The judgment control means 1b is operated by the power switch 6. When the power switch 6 is turned on when the load 3 and the battery 2 are not connected now, the determination control means 1b
Sends an operation start signal to the switch control means 1c.

The judgment control means 1b is a switch control means 1
Before sending an operation start signal input to c, a measurement data acquisition signal is sent to the measurement data acquisition means 1a3.

The measurement data fetching means 1a3 sends the fetch timing to the AD converter 1a2, thereby receiving the measured voltage data sent from the AD converter 1a2 and transferring it to the judgment control means 1b. The measured voltage data in this case is
Open circuit voltage (OCV).

The judgment control means 1b uses the open circuit voltage (OC
V) is received and stored. After this, the switch control means 1
c sends a control signal to the switch circuit 4 to load the load 3 and the battery 2
To connect. This turns on the load 3.

Then, the judgment control means 1b again sends a measurement data fetching signal to the measurement data fetching means 1a3.

The measurement data fetching means 1a3 sends the fetch timing to the AD converter 1a2, whereby the measured voltage data sent from the AD converter 1a2 is received and transferred to the judgment control means 1b. The measured voltage data in this case is
It is a closed circuit voltage (CCV).

The judgment control means 1b uses the closed circuit voltage (CC
V) and calculate the difference from the previously stored open circuit voltage (OCV). This open circuit voltage (OCV) and closed circuit voltage (CC
Since the voltage difference V) is related to the degree of consumption of the battery, that is, the remaining capacity as described above, the remaining capacity of the battery can be confirmed by using a conversion table or conversion formula prepared in advance.

On the basis of the confirmed remaining battery capacity, the judgment control means 1b sends it to the display device 5 via the display drive circuit 1d.
To display. Any display method may be used. For example, the battery remaining capacity may be displayed continuously by a rod-shaped LCD, or the battery remaining capacity may be displayed stepwise by a plurality of LCDs.

FIG. 2 is an explanatory view of the principle of the battery remaining capacity monitoring according to the present invention. (A) shows how the closed circuit voltage (CCV) and the open circuit voltage (OCV) of the battery voltage VB drop as the battery wears down and the battery remaining capacity decreases with time.

It can be seen that the voltage difference between the open circuit voltage (OCV) and the closed circuit voltage (CCV) increases with time. The voltage difference dVt2 at the time t2 is larger than the voltage difference dVt1 at the time t1. That is, the difference in voltage increases as the remaining battery capacity decreases. Therefore, the remaining battery capacity can be confirmed based on this voltage difference, and the remaining battery capacity at any time can be displayed.

Another advantage of this principle is that since the difference between the two voltages is small due to individual batteries, it is possible to grasp the remaining battery capacity without being affected by the usage environment or usage situation. The open circuit voltage (OCV) and the closed circuit voltage (CCV) have different values due to variations in each battery. Therefore, as in the prior art, the open circuit voltage (OCV) or closed circuit voltage (CCV) value of each battery itself causes a large error when monitored independently.
In this principle, the control is performed based on the difference between the two voltages, so that the error can be reduced.

In FIG. 2 (b), when comparing the battery A and the battery B, there are variations in the OCV and B OCV, and also in the CCV and the CCV. However, the difference between the two voltages and the variation between the instep dVt and the second dVt are small. As described above, according to the principle of the present invention, it is possible to accurately check the remaining battery capacity and display the remaining capacity by absorbing the variation of each battery.

[0022]

As described above, the battery remaining capacity monitoring apparatus according to the present invention pays attention to the characteristic that the difference between the open circuit voltage and the closed circuit voltage increases as the capacity of the battery decreases and the capacity decreases. Using this, the open circuit voltage and the closed circuit voltage of the battery used at a certain time are measured, and the battery remaining capacity at that time is confirmed based on the difference between these voltages.Therefore, at any time during normal use, It is possible to judge the remaining battery life and display it, so it is possible to predict the dead battery, which is very convenient for daily use.

[Brief description of drawings]

FIG. 1 is a functional block diagram of a battery remaining capacity monitoring device according to the present invention.

FIG. 2 is an explanatory view of the principle of remaining battery capacity monitoring according to the present invention.

[Explanation of symbols]

 1 Battery Remaining Capacity Monitoring Device 1a Voltage Measurement Means 1a1 Voltage Measurement Circuit 1a2 AD Converter 1a3 Measurement Data Acquisition Means 1b Judgment Control Means 1c Switch Control Means 1d Display Drive Circuit 2 Battery 3 Load 4 Switch Circuit 5 Indicator 6 Power Switch

Claims (1)

[Claims] 1. A voltage measuring means measures an open circuit voltage and a closed circuit voltage of a used battery in response to a switching operation of a switch control means for controlling connection between a battery and a load at a certain time point, and based on a difference between these voltages. Then, the determination control means confirms the remaining battery capacity at that time, the remaining battery capacity monitoring device.