JPH02259525A - Display device for remaining capacity of battery - Google Patents

Abstract

PURPOSE:To efficiently prevent an occurrence of battery exhaust by providing a detecting circuit for input voltage difference when the device is equipped on an electric motorcar as a remaining capacity meter for power battery. CONSTITUTION:Threshold voltages are successively set step by step in plural comparators 5a-5e, either a non-inverse or inverse input terminal of which is connected to plural transistors 4a-4e dividing a reference voltage of the reference voltage source, and the detecting circuit 3 for input voltage difference furnished with these comparators is provided. The battery 2 is connected to the remaining input terminals of comparators 5a-5e, and corresponding to this, each one of light emitting means 7a-7e is connected to output terminals of the comparators 5a-5e through normally-closed switches 6a-6e, then current control means 10 are provided between the means 7a-7e and the detecting circuit 3. An output signal from the detecting circuit 3 is received by the control means 10 wherein current amounts flowing to the means 7a-7e are gradually made to increase along with the quantity decrease of lamp lighting of the means 7a-7e due to the voltage drop of battery 2, then the occurrence of the battery exhaust is prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a battery remaining capacity display device, and
The present invention relates to a battery remaining capacity display device suitable for displaying the remaining capacity of a power battery of an electric vehicle.

[Conventional technology]

Conventionally, electric vehicles have been equipped with a remaining capacity meter 51 as shown in FIG. This remaining capacity meter 51
is actually used by being mounted on a panel inside the driver's seat (not shown).

The remaining capacity meter 51 includes a plurality of light emitting diodes (hereinafter referred to as rLEDs) 53.5 arranged in a straight line corresponding to a window 52a formed in the center of the display panel 52.
3. It is a bar graph-like display consisting of... And these light emitting diodes 53, 53 . ...
... are turned off one by one as the capacity of the battery (power battery) decreases, and the remaining capacity is displayed by the number of remaining lit LEDs 53.

[Problem to be solved by the invention]

However, in the above conventional example, the remaining capacity is displayed using a plurality of LEDs 53 arranged in a straight line. The display becomes difficult to read, making it impossible to accurately judge the remaining capacity of the battery, and sometimes leading to the so-called "depleted battery."

[Purpose of the invention]

The object of the present invention is to improve the disadvantages of the conventional example, and particularly, to provide a battery capable of effectively preventing the occurrence of "depleted battery" when installed in an electric vehicle as a residual capacity meter of a power battery. An object of the present invention is to provide a remaining capacity display device.

[Means to solve the problem]

In the present invention, a plurality of resistors divide a reference voltage from a reference power supply, and each resistor is connected to either its non-inverting input terminal or its inverting input terminal, and a threshold voltage is sequentially set in steps. The input voltage difference detection circuit is provided with a plurality of comparators. A battery is connected to the remaining input terminal (either the inverting input terminal or the non-inverting input terminal) of each of the comparators, and a normally closed switch or a normally open switch is connected to the output terminal of each comparator. The light emitting means constituting the display section is
A current control means is interposed between these light emitting means and the input terminal difference detection circuit. This current control means receives an output signal from the input voltage difference detection circuit, and has a current amount control function that sequentially increases the amount of current flowing through each light emitting means as the number of light emitting means decreases due to a drop in battery voltage. The structure is such that it has the following.

This aims to achieve the above-mentioned purpose.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

The embodiment shown in FIG.
The input voltage difference detection circuit 3 is connected to the input voltage difference detection circuit 3. The input voltage difference detection circuit 3 includes five resistors 4a connected in series between the reference power source 1 and ground to divide the reference voltage E0 from the reference power source.

4b, 4c, 4d, and 4e, and five comparators 5a, 5b, 5c, and 5d whose non-inverting input terminals are connected to these resistors 4a to 4e, respectively, and whose threshold voltages are sequentially set in a stepwise manner.

5e. The inverting input terminals of these comparators 5a to 5e are connected to each other, and
Battery 2, which is a power battery for an electric vehicle, with its negative electrode grounded
connected to the positive terminal of the

Control terminals of analog switches 6a to 6e as normally closed switches are connected to the output terminals of the comparisons i5a to 5e, respectively.

Here, the analog switches 6a to 6e are (
The input of the control terminal is rl, (low) and is turned on (ON).One end (input end) of these analog switches 6a to 6e is connected to each other, and It is connected to the display power supply 11. Also, these analog switches 6a to 6e
The other end (output end) is connected to the anode sides of light emitting diodes (hereinafter referred to as rLEDJ) 7a to 7e as light emitting means, respectively. These l7ED, 7a
7e to 7e actually constitute a bar graph similar to the conventional example described above. Further, the cathodes of these LEDs 7a to 7e are connected to an amplifier 12 which is mutually connected and constitutes a current control means 10 which will be described later.

An adder 8 is connected to the output terminals of the comparators 5a to 5e. This adder 8 includes comparators 5a to 5.
It has a function of controlling the amount of current shown in FIG. 1 by receiving the output signal of e, adding it (performing a predetermined calculation), and changing the gain (amplification degree) of the amplifier 12. ing. That is, in this embodiment, adder 8 and amplifier 1
2 constitutes a current control means 10. As will be described later, this current control means 10 controls each L
It has a function of increasing the amount of current flowing through the ED in stages as the discharge of the battery 2 increases (see FIG. 2).

A power supply 9 is connected to the adder 8, and this power supply 9 also serves as a power supply for the reference power supply 1 described above.

Moreover, between the comparator 5d and the analog switch 6d,
An alarm buzzer 13 is interposed.

Next, the overall function and operation of the above embodiment will be explained.

In this embodiment, the reference voltage E0 of the reference power supply 1 is the battery 2
Open-circuit voltage when fully charged (it is known that the open-circuit voltage of lead-acid batteries is proportional to the capacity) V.

is set approximately equal to. That is, E, -■.

It becomes. In addition, resistors 4a to 4e for each voltage division
The resistors used here all have the same resistance value.

Therefore, the potentials of the connection points A to E shown in FIG. 1 are as follows. That is, 4/SEOζ415■ at point A. .

3E, 115ζ3■ at point B. 15° 2E, 15ζ2■ at 0 points. 15° E015 at point D! =iV. 15° O at point B It is.

When the battery 2 is fully charged, the outputs of the comparators 5a to 5e constituting the input voltage difference detection circuit 3 are all "L", so all the analog switches 6a to 6e are "on", and the LEDs 7a to 7e are turned on. All lights up. The brightness of each LED in this case is f shown in FIG.

Next, in a state after the battery has been discharged by 20%, the output of the comparator 5a becomes "rH (high)", the analog switch 6a becomes "off", and the LED 7a turns off. At this time, the current control means 10 controls the lighting of the LED 7.
The current values flowing through these LEDab to 1e are controlled so that the brightness of LEDs b, 7c, 7d, and 7e becomes g shown in FIG. In reality, this current control is performed by the current control means 1.
This is done by changing the gain of the amplifier 12 in response to the output signal from the comparator 5a.

Similarly, when the battery 2 is 40% or 60% discharged, the current control means 10 controls the current value flowing through each LED so that the brightness of the lit LED becomes i as shown in FIG. control.

Furthermore, when the battery discharge reaches 80%, comparator 5
In addition to a to 5c, the output of 5d also becomes "H", and the alarm buzzer 13 turns "on" to issue an alarm. At this time, analog switches 6a, 6b, 6c, 6d
is turned off, LEDs 7a, 7b, 7c, and 7d are turned off, and only LED 7e is lit. in this case,
The current control means 10 receives the output signals from the comparators 5a, 5b, 5c, and 5d, and controls the current value flowing through the LED 7e so that the brightness of the LED 7e that is lit becomes j shown in the second time.

As explained above, according to this embodiment, as the capacity of the battery 2 decreases (as the capacity of the battery 2 decreases), the LEDs forming the bar graph decrease.
In addition to turning off the LEDs one by one, the brightness of the LEDs that are lit can be set gradually higher, making it possible to clearly display the remaining battery capacity as the capacity decreases. There is an advantage that it is possible to effectively prevent the battery 2, which is a power battery, from going into a so-called "depleted battery" state.

Furthermore, when the discharge of the battery 2 reaches 80%, the warning buzzer 12 can alert the driver, making it possible to avoid deep discharge of the battery 2, and
It also has the advantage of extending the life of the

〔Effect of the invention〕

The present invention is configured and functions as described above.

According to this, a decrease in the open circuit voltage (decrease in capacity) of the battery is detected by the action of the input voltage difference detection circuit according to a threshold voltage set in advance in steps, and the light emitting means constituting the display section is sequentially activated. By the function of the current control means, as the number of lit light emitting means decreases, the brightness of the light emitting means that are lit can be gradually increased, thereby increasing the remaining capacity of the power battery of the electric vehicle. When used for display purposes, the remaining capacity can be displayed more clearly as the capacity of the power battery decreases. This prevents the battery from going into a so-called "depleted battery" state even if you are driving during the day.
It is possible to provide a battery remaining capacity display device that is unprecedented and excellent in that it can effectively prevent such problems.

In the above embodiment, the reference power source is connected to the non-inverting input side of each comparator, and the battery, which is the object of remaining capacity detection, is connected to the inverting input side, and the LED is turned on and off.
Although the case where a normally closed type analog switch is used as the switch for "off" is illustrated, the present invention is not limited to this.On the contrary, the reference power supply may be connected to the inverting input side of each comparator. In addition, a battery may be connected to the non-inverting input side, and a normally open type switch may be used as a switch for turning the LED on and off.

In addition, the current control means is composed of a microcomputer, etc., and this microcomputer performs a predetermined calculation according to the output of the input voltage difference detection circuit ("L" level output) and controls the display power supply, thereby controlling the number of lit LDHs. A configuration in which the amount of current flowing through each LED is increased as the amount of current flowing through each LED is decreased is also possible.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the configuration of an embodiment of the present invention, and Fig. 2 shows the battery discharge amount and LED of the embodiment shown in Fig. 1.
A diagram showing the relationship with display brightness, and FIG. 3 is an explanatory diagram showing a conventional example. 1...Reference power supply, 2...Battery, 3
...Input voltage difference detection circuit, 4a, 4b, 4c,
4d, 4e...Resistor, 5a, sb, 5c, 5
d, 5e... Comparator, 6 a, 6 b,
6 c, 6 d, 6 e - Analog switches as normally closed switches, 7 a, 7 b. 7c, 7d, 7e...LED as light emitting means
, 10... Current control means. Figure 2 Figure 3

Claims (1)

[Claims] (1) A plurality of resistors divide the reference voltage from the reference power supply, and either the non-inverting input terminal or the inverting input terminal is connected to each resistor, and the threshold voltage is set in a stepwise manner. an input voltage difference detection circuit comprising a plurality of comparators, a battery is connected to the remaining input terminal of each of the comparators, and a normally closed switch or a normally closed switch is connected to the output terminal of each of the comparators. One light emitting means constituting the display section is connected through each open switch, and a current control means is interposed between these light emitting means and the input voltage difference detection circuit, and this current control means It has a current amount control function that receives the output signal of the input voltage difference detection circuit and sequentially increases the amount of current flowing through each light emitting means as the number of light emitting means decreases due to a decrease in the voltage of the battery. A battery remaining capacity display device featuring: