JPH0447682A - Chargeable/dischargeable battery - Google Patents

Abstract

PURPOSE:To facilitate management of the charged/discharged condition and reduce troubles such as overcharge and out of battery by measuring the terminal voltage with a measuring means, displaying the measuring result on a display means, and allowing this means to work according to necessity. CONSTITUTION:A terminal 7 is connected with a pos. electrode terminal 2a, and a terminal voltage VDD is impressed on the terminal 7, divided by resistances R1, R2, and fed to one of the input ends of a comparator 11. The other input end of the comparator 11 is fed with a reference voltage given by a reference voltage supplier 12. The values of resistances R1, R2 are so arranged that the output voltage OUT given to a terminal 13 nullifies when the terminal voltage VDD is become equal to the specified voltage Vmin. A voltmeter 4 is installed being adjusted by another resistance R3 so as to indicate the max. value when the terminal voltage VDD is identical to the rated voltage Vt. This enables enlarged display of a minute change in the terminal voltage during the NiCd battery in discharging.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a chargeable and dischargeable battery used in a portable terminal device such as a handy terminal.

(Prior art) For rechargeable and dischargeable batteries, such as nickel-cadmium batteries (hereinafter referred to as nickel-cadmium batteries), which are often used in handheld terminals, it is important to charge them appropriately according to the usage conditions, and to avoid overcharging. This will shorten the battery life, and if the battery is insufficiently charged, it will not be possible to process the battery during operation.

In order to prevent work stoppages due to running out of batteries during operation, conventionally the handy terminal detects the terminal voltage of the nickel-cadmium battery, and if the voltage drops below a certain level, a warning message like the one shown in Figure 12 is sent. A method of displaying on a liquid crystal display device has been adopted.

That is, in the voltage detection circuit of FIG. 9, the supply voltage (terminal voltage of the battery) VDD applied to the terminal 51 is divided by the resistors 52 and 53, and the output of the reference voltage source 55 is determined by the comparator/hysteresis circuit 54. Voltage (reference voltage)
If the voltage drops below the reference voltage -VDET or +VDET, the output transistor 56 is turned on and the ground potential vSS is output as the output voltage OUT of the terminal 57.

The operating state during this period is as shown in the time chart shown in FIG. The warning message is displayed when the output voltage OUT is checked by a CPU (not shown) using a timer interrupt process and is at VSS.

In addition, regardless of the warning message, for example, as shown in FIG. When it drops to VSS, L
A method of lighting up the ED59 is also performed.

In addition to the above method, measuring the terminal voltage with a tester or the like is another method for determining the voltage capacity of a battery, but this method is not suitable for use in the field.

(Problem to be Solved by the Invention) However, in the past, it was not possible to detect whether the battery had enough remaining capacity for operation unless it was actually installed in a handy terminal etc. and used. There is a problem in that unless the charging and discharging states of individual batteries are adequately managed, it is inevitable that the batteries will run out during operation.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a chargeable and dischargeable battery that allows easy management of charging and discharging states and reduces troubles such as overcharging and running out of the battery.

[Configuration of the Invention (Means for Solving the Problems) The chargeable and dischargeable battery of the present invention includes a battery that measures terminal voltage.
111 constant means, display means for displaying the measurement results of this measuring means, and switch means for operating the measuring means as necessary.

(Function) By measuring the terminal voltage with the measuring means, displaying the measurement result on the display means, and enabling the above measuring means to operate as necessary, the charging/discharging state can be checked independently. This also facilitates management when handling a large number of batteries. In addition, since it is possible to grasp the variation in remaining capacity caused by the magnitude of current consumption, it is possible to reduce problems such as overcharging and battery exhaustion.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows the external structure of a voltmeter 1 Ni-Cd battery according to the first embodiment. That is, reference numeral 1 denotes a plastic battery case in which four 2-cadmium 11 batteries (not shown) are connected in series and accommodated. Here, since the rated voltage of a NiCd cell is, for example, 1.2 volts, the voltage of 4.8 volts for four batteries is the positive terminal 2a.
It is designed to be output to the s negative electrode terminal 2b. 3 is a notch for locking the Ni-Cd battery when it is inserted into the terminal. On the front side of housing 1,
An ultra-small and thin voltmeter 4 and a check button switch (non-lock) 5 for measuring terminal voltage only when necessary are provided. A voltmeter 4 and a check button switch 5 are arranged on a printed wiring board 6 and have an integral structure.

FIG. 2 shows the electrical circuit. That is, terminal 7
is connected to the positive terminal 2a, and the terminal 8 is connected to the negative terminal 2b, so that when the check button switch 5 is pressed, current flows through the circuit. This is to avoid consuming wasteful measurement current when unnecessary. The adjustment resistor 9 is composed of R1 and R2 and has two purposes. One reason is to allow a sufficient load current to flow through the Ni-Cd battery during a voltage check.

The reason for this will be explained using FIG. 4. As shown in FIG. 4, the terminal voltage e when a load resistor R is connected to a nickel-cadmium battery is expressed by the following equation (1) depending on the internal resistance r of the battery.

In other words, the smaller R is, the more the influence of r is on the terminal voltage e.
appears in On the other hand, the internal resistance r increases according to the amount of discharge of the NiCd battery. For example, if the terminal voltages when a load resistance R of 50Ω and 10Ω is connected to a NiCd battery with a capacity of 400mAH are el and e2, respectively, the changes over time are as shown in Table 1 below, and the values of r from el and e2 are as follows. Formula (2) is obtained, which is also shown in Table 1 below.

table As shown in Table 1 above, the value of r gradually increases.

FIG. 5 is a graph of el e2 and r in Table 1 above. From these data, it can be seen that the discharge amount of a NiCd battery is expressed as the terminal voltage when a sufficient load current is passed.

The other purpose of the adjustment resistor 9 is to adjust the terminal voltage VDD of the NiCd battery.
This is to display only the change in voltmeter 4 on the voltmeter 4. That is, the terminal 7 in FIG. 2 is connected to the positive terminal 2a as described above, and the terminal voltage VDD is applied to this terminal 7.
It is divided by resistors R1 and R2 and applied to one input terminal of comparator]1. A reference voltage from a reference voltage source 12 is applied to the other input terminal of the comparator]l.

The values of the resistors R1 and R2 are determined so that when the terminal voltage VDD becomes equal to a predetermined voltage Vmin, the output voltage OUT outputted to the terminal 13 becomes zero. -Power, voltage=14 is adjusted by resistor R3 so that it indicates the maximum value when the terminal voltage VDD or the rated voltage Vt. By doing so, it becomes possible to magnify and display slight changes in the terminal voltage during discharging of the NiCd battery.

In addition, the indication of the voltmeter 4 is 0 to 100 in the embodiment shown in FIG.
However, if the remaining capacity is displayed in mAH or the load current on the handy terminal is constant,
Usage ■It is also possible to convert and display remaining capacity time.

Next, a second example will be described. Figure 6 shows the LED
This shows the appearance of a 2-cadmium battery with an indicator.

That is, the voltage in the first embodiment shown in FIG. 1 = 1
The other structure is the same as in FIG. 1, except that 4 is replaced by two LEDs 24 and 25. FIG. 7 shows the electric circuit, in which the terminal 14 is connected to the positive terminal 2a, and the terminal 15 is connected to the negative terminal 2a.
b, respectively. Current flows through the circuit only when the check button switch 5 is pressed. . The resistance value of the variable resistor 26 is selected to be low so as to provide a sufficient load current to the Ni-Cd battery. The variable resistor 26 used here has two (U actuators 26a,
26b, the slider 26a is connected to the base of an NPN transistor 28 via a resistor 27, and the slider 26b is connected to the base of an NPN transistor 30 via a resistor 29. . The transistor 28 drives the LEt) 24, and the transistor 30 drives the LED 25. Here, the position of the slider 26a is adjusted so that the LED 24 lights up when the terminal voltage VDD applied to the terminal 14 is, for example, 3.5 volts or more.

Further, the position of the slider 26b is adjusted so that the LED2+5 lights up when the terminal voltage VDD is, for example, 4.0 volts or more. Note that 31 and 32 are resistors for current limiting.

By doing this, as shown in Table 2 and Figure 8 below, depending on the lighting status of the two LEDs 24 and 25, it is possible to tell whether the battery has enough remaining capacity, some 1 remaining, or no battery at all. can be known.

Table 2 Note that in the second embodiment, the case where two LEDs are used is described, but if three or more are used, it becomes possible to display the remaining capacity in more detail.

In addition, in the circuit shown in Figure 7, the operating power supply for LEDs 24 and 25 uses the terminal voltage VDD as it is, but generally L
If the operating voltage of the ED is 2.0 to 2.5V or higher, it will be able to light up sufficiently, so even if the terminal voltage VDD decreases, it will not affect the blinking operation of the LEDs 24 and 25 mentioned earlier. do not have.

In both the first and second embodiments described above, it is possible to check the remaining capacity from the outside even when the NiCd battery is attached to the handy terminal.

In addition, although the voltmeter and LED have been given as two examples of means for displaying measured values, other display devices such as a liquid crystal display device may be used. Furthermore, although a button switch was used as a switch means to measure the terminal voltage only when necessary, it is not limited to this.
For example, other switching means such as a touch switch may be used.

[Effects of the Invention] As detailed above, according to the battery capable of charging and discharging ports of the present invention, the charging and discharging status can be checked on the body without using other equipment, making it possible to handle a large number of batteries. This also makes management easier. Furthermore, since it is possible to grasp the variation in remaining capacity caused by the magnitude of current consumption, problems such as overcharging and battery exhaustion can be reduced.

[Brief explanation of the drawing]

1 to 5 are for explaining the first embodiment of the present invention. FIG. 1 is a perspective view showing the external structure of a two-cadmium battery with a voltmeter, and FIG. 2 is a structure showing an electric circuit. Figure 3 shows the relationship between the discharge characteristics of the terminal voltage and the voltmeter display, Figure 4 shows the equivalent circuit diagram when a load resistor is connected, and Figure 5 shows the change in terminal voltage and internal resistance over time. The graphs shown in FIGS. 6 to 8 are for explaining the second embodiment of the present invention. FIG. 6 is a perspective view showing the external structure of a two-cadmium battery with an LED display, and FIG. 7 is an electric circuit. FIG. 8 is a diagram showing the relationship between the discharge characteristics of the terminal voltage and the LED display, and FIGS. 9 to 12 are for explaining the conventional technology.
Fig. 9 is a configuration diagram of the voltage detection circuit in the handy terminal, Fig. 10 is a time chart explaining the operation of the voltage detection circuit in Fig. 9, and Fig. 11 is a configuration showing another example of the voltage detection circuit in the handy terminal. 12 are diagrams showing an example of a warning message displayed on a handy terminal. DESCRIPTION OF SYMBOLS 1... Battery housing, 2a... Positive electrode terminal, 2b... Negative electrode terminal, 4... Voltmeter, 5... Check button switch, 6... Printed wiring board, 24... Light emitting Diode, 25... Light emitting diode.

Claims (1)

[Claims] The present invention is characterized by comprising a measuring means for measuring a terminal voltage, a display means for displaying the measurement result of the measuring means, and a switch means for operating the measuring means as necessary. A rechargeable and dischargeable battery.