JPH08185895A - Battery pack and small electronic equipment - Google Patents

Abstract

PURPOSE: To display the residual capacity and fully charged state of a secondary battery by providing a display section for showing information on voltage across the terminals of the battery, and generating display drive voltage, using the voltage across the terminals as drive voltage for supply to the display section. CONSTITUTION: A secondary battery residual capacity display system 1 is formed out of a liquid crystal drive circuit 2 and a liquid crystal display section 3. The circuit 2 sends a drive signal corresponding to the terminal voltage of a secondary battery 4 to the section 3. The display section 3 shows the residual capacity and charged state of the battery 4, depending on the drive signal from the circuit 2. According to this construction, residual capacity or the like can be displayed at low power consumption equal to or below the self-discharge current of the battery 4 as well as at low cost.

Description

Detailed Description of the Invention

[0001]

[Table of Contents] The present invention will be described in the following order. Field of Industrial Application Conventional Technology Problems to be Solved by the Invention Means for Solving the Problems (FIGS. 1 and 10) Actions (FIGS. 1 and 10) Embodiments (FIGS. 1 to 10) Effects of the Invention

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery pack and a small electronic device, and is particularly suitable for being applied to a device having a secondary battery residual amount display portion.

[0003]

2. Description of the Related Art Conventionally, secondary batteries such as lithium ion have been widely used in small portable equipment. Some small portable devices, battery packs, and the like that use a secondary battery are provided with a remaining amount display section that indicates the usage state of the secondary battery.

[0004]

However, not all batteries such as small portable devices using a secondary battery have a remaining amount display. For this reason, when the battery is used abruptly, the terminal voltage of the secondary battery must be measured each time to identify the remaining amount.

There is also a product of a nickel-cadmium secondary battery having a remaining amount display portion by an LED. However, in the case of LEDs, it is difficult to avoid an increase in drive power loss. Therefore, the LED
There is a problem that the cost increases, including the amount of the microcomputer used to drive the.

The present invention has been made in consideration of the above points, and it is an object of the present invention to propose a battery pack and a small electronic device which can reduce the cost and power consumption and can display the remaining amount and the full charge state.

[0007]

In order to solve the above problems, in the present invention, the battery pack (30) accommodating one or more secondary batteries (4) is made of a reflective liquid crystal, and the reflective liquid crystal is used. A display unit (3) for displaying terminal voltage information of one or a plurality of secondary batteries (4);
Alternatively, a driving means (2) is provided, which uses a voltage between terminals of the plurality of secondary batteries (4) as a driving voltage, generates a driving voltage for display from the driving voltage, and supplies the driving voltage for display to the display unit (3).

Further, according to the present invention, in a small electronic device which uses a battery pack containing one or a plurality of secondary batteries (4) as a driving power source, it is made of a reflective liquid crystal, and the reflective liquid crystal can be used for the battery pack. A display unit (3) for displaying voltage information between terminals, and a drive means (2) for generating a display drive voltage from the drive voltage by using a voltage between the terminals of the battery pack as a drive voltage and supplying the drive voltage to the display unit (3). Equipped with.

[0009]

In the battery pack (30) and the small electronic equipment, the display unit (3) is made of the reflective liquid crystal and displays the terminal voltage information of one or more secondary batteries (4) by the reflective liquid crystal. A driving means (2) that supplies a display driving voltage from the driving voltage that is the inter-terminal voltage of one or more secondary batteries (4) and supplies the driving voltage for display to the display unit (3). , Reduce cost and power consumption, and display remaining capacity and full charge status.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a secondary battery remaining amount display system 1 of the present invention. The secondary battery remaining amount display system 1 includes a liquid crystal drive circuit 2 and a liquid crystal display unit 3. This liquid crystal drive circuit 2
The drive signal corresponding to the terminal voltage of the secondary battery 4 is output to the liquid crystal display unit 3.

A configuration example of the liquid crystal drive circuit 2 is shown in FIG. The liquid crystal drive circuit 2 has a CMOS inverter 5. The positive and negative electrodes V _B of the secondary battery 4 are divided by the voltage dividing circuit R ₁ ,
It is divided by R ₂ . This voltage is supplied between V _{DD and} V _SS as the power supply voltage of the astable multivibrator using the CMOS inverter 5, and then the drive voltage output Vdisp for liquid crystal display is obtained.

This drive voltage output Vdisp is given by the following equation

[Equation 1] Ask for. Since the current consumption of the CMOS is several [μA] or less, by setting R ₁ + R ₂ in the equation (1) to an arbitrary value, the current consumption of the entire liquid crystal drive circuit 2 becomes the self-discharge current of the secondary battery 4. You can easily set the following.

FIG. 3 shows the discharge characteristics of the secondary battery 4. When the use setting of the secondary battery 4 is in the range of V _{B1 to} V _B2 , the drive AC output Vdisp1 inverted by the liquid crystal drive circuit 2
The output of Vdisp2 is applied to the transparent electrode section of the liquid crystal display section 3.

FIG. 4 shows a voltage-transmittance characteristic curve of the display liquid crystal. This characteristic curve shows a transmission type (normally white TN liquid crystal) characteristic. As can be seen from FIG. 4, when the liquid crystal display voltage changes from Vdisp1 to Vdisp2 in accordance with the voltages V _{B1 to} V _B2 of the secondary battery 4, the transmittance of the liquid crystal corresponding to the liquid crystal display voltages Vdisp1 to Vdisp2 is T ₁
It changes to ~T _2. The density filter of the liquid crystal display unit 3 is determined by using this characteristic.

Next, FIGS. 5 and 6 show examples of display of the remaining amount of the secondary battery 4. FIG. 5A is an example of segment display.
A plurality of segments 10 are provided between the working voltage ranges V _{B1 and} V _B2 , and the remaining amount is displayed according to the arrangement position. An enlarged view of each segment 10 shown here is shown in FIG. The segment 10 includes a transparent electrode portion 11 and a density filter 12 adjacent to or surrounding the transparent electrode portion 11.

Incidentally, the density filter 12 surrounding the transparent electrode portion 11 is set to a density corresponding to the Vdisp voltage.
For example, when Vdisp1 is displayed in the characteristic shown in FIG. 4, the density filter 12 that gives reflected light corresponding to the transmittance T ₁ is attached. Therefore, when the voltage of the secondary battery 4 becomes equal to the voltage for displaying the segment 10, the reflectance in the segment 10 is determined by the density filter 12 and the transparent electrode portion 11.
Will be indistinguishable.

FIGS. 6A to 6D show examples of display states of the remaining amount display of the secondary battery 4. This is an example of the position display of the remaining amount in the horizontal direction. FIG. 6A shows the display state when the battery voltage is V _B1 , that is, when the battery is fully charged.
(B) and (C) show the display state when there is a remaining battery voltage. Further, FIG. 6D shows the display state when the battery voltage is V _B2 , that is, when the discharge is completed.

The liquid crystal display section consisting of four segments 10a to 10d has a density filter 12 of different density.
a to 10d. Four segments 10a-1
0d, the density filter 1 of the segment 10a at one end
The density of 2a is made to correspond to a full charge, and the density of the density filter 12d of the segment 10d at the other end is made to correspond to the end of discharge. The density is changed in the order of arrangement from the density filter 12a at one end to the density filter 12d at the other end. Therefore, the density filter 12 of the segment 10 and the transparent electrode portion 11
The state of the battery voltage can be discriminated by making the values equal to each other.

For example, when a display pattern or a character is displayed on the transparent electrode portion 11, the pattern character cannot be read. An example of these displays is shown in FIG. FIG. 7A shows a pattern display example, and FIG. 7B shows a character display example. In both cases, the density of the density filter 12 around the transparent electrode portion 11 is made to correspond to the voltage at the end of discharge. Therefore, when the display is dark, it indicates a charged state, and when the display becomes faint and unreadable, it indicates a discharge end state.

According to the above construction, by displaying the liquid crystal display section 3 in response to the drive signal from the liquid crystal drive circuit 2, the remaining amount can be reduced at a low power consumption and a low cost less than the self-discharge current of the secondary battery 4. Can be displayed.

In the above embodiments, the CMOS inverter 5 is used as the driving rectangular wave oscillating circuit of the liquid crystal driving circuit 2. However, the present invention is not limited to this, and the driving rectangular wave oscillating circuit may be used. For example, other than the CMOS inverter 5 may be used.

[0023] In the above embodiment, the secondary battery voltage V _B described for the liquid crystal driving circuit 2 to provide through voltage divider circuit R _1, R ₂ to astable multivibrator oscillator circuit, the present invention is limited to this Instead, for example, as in the liquid crystal drive circuit 20 shown in FIG. 8, the secondary battery voltage V _B is directly oscillated by the astable multivibrator oscillating circuit, and the voltage dividing circuit 21 is inserted into the output. Is also good. In this case, since the voltage division ratio of the voltage dividing circuit 21 can be set to an arbitrary value, it is optimal for the display by the plurality of segments shown in FIG.

Further, in the above-mentioned embodiment, the discharge start voltage V _B1 and the end voltage V _B2 are different, but the present invention is not limited to this, and the discharge start voltage V _{B1 is} not limited to this.
When the difference between the end voltage V _B2 and the end voltage V _B2 is too small to sufficiently change the reflectance of the liquid crystal, it is preferable to use the booster circuit 22 together as shown in FIG. In this case, by appropriately selecting the step-up ratio n and the voltage dividing circuit 21, a wider range of display freedom can be obtained. Further, by adding a temperature compensating circuit during the generation of Vdisp in the drive circuit 2, it is possible to cancel the temperature characteristic of the voltage-transmittance characteristic shown in FIG. 4 and display the remaining amount more stable with respect to the temperature. .

Further, in the above-mentioned embodiment, the secondary battery remaining amount display system 1 including the liquid crystal drive circuit 2 and the liquid crystal display section 3 has been described, but the present invention is not limited to this, and FIG.
Similar effects can be obtained with a battery pack 30 having a secondary battery remaining amount display system 1 as shown in (A) to (C), a small electronic device, or the like.

[0026]

As described above, according to the present invention, the reflective liquid crystal is used, and the reflective liquid crystal is used to display the terminal voltage information of one or more secondary batteries and one or more. By using the voltage between the terminals of the secondary battery as a drive voltage and providing drive means for generating a drive voltage for display from the drive voltage and supplying the drive voltage to the display section, cost and power consumption are reduced,
It is possible to realize a battery pack and a small electronic device capable of displaying the remaining amount and the full charge state.

[Brief description of drawings]

FIG. 1 is a connection diagram showing a configuration of a secondary battery remaining amount display system according to an embodiment of the present invention.

FIG. 2 is a connection diagram showing a configuration of a liquid crystal drive circuit in the secondary battery remaining amount display system of FIG.

FIG. 3 is a characteristic curve diagram used for explaining secondary battery discharge characteristics.

FIG. 4 is a characteristic curve diagram for explaining the voltage-transmittance characteristic of liquid crystal.

FIG. 5 is a schematic diagram showing a display example of a secondary battery remaining amount display.

FIG. 6 is a schematic diagram showing a display example of a secondary battery remaining amount display.

FIG. 7 is a schematic diagram showing a display example of a single segment.

FIG. 8 is a connection diagram showing a configuration of another liquid crystal drive circuit.

FIG. 9 is a connection diagram showing the configuration of another liquid crystal drive circuit.

FIG. 10 is a schematic diagram showing a battery pack having a secondary battery remaining amount display system.

[Explanation of symbols]

1 ... Secondary battery remaining amount display system, 2, 20 ... Liquid crystal drive circuit, 3 ... Liquid crystal display section, 4 ... Secondary battery, 5 ... C
MOS inverter, 10 ... Segment, 11 ... Transparent electrode part, 12 ... Concentration filter, 21 ... Voltage dividing circuit, 2
2 ... Booster circuit, 30 ... Battery pack.

Claims (10)

[Claims] 1. A battery pack in which one or a plurality of secondary batteries are housed, the display unit being made of a reflective liquid crystal and displaying the terminal voltage information of the one or a plurality of secondary batteries by the reflective liquid crystal. And a drive means which uses the voltage between the terminals of the one or more secondary batteries as a drive voltage and generates a display drive voltage from the drive voltage and supplies the display drive voltage to the display section. 2. The driving means comprises a voltage dividing means for dividing the driving voltage applied from the one or a plurality of secondary batteries according to the voltage-transmittance characteristic of the reflective liquid crystal, and the voltage dividing means. 2. The battery pack according to claim 1, further comprising oscillating means for inverting the divided voltage generated as described above in an alternating current and supplying it as the display drive voltage. 3. The drive means comprises an oscillating means for AC-inverting the drive voltage applied from the one or a plurality of secondary batteries, and an oscillation output of the oscillating means for a voltage-transmittance characteristic of the reflective liquid crystal. 2. The battery pack according to claim 1, further comprising: a voltage dividing unit that divides the voltage according to the above and outputs the driving voltage for display. 4. The battery pack according to claim 1, 2 or 3, wherein the display unit comprises a booster unit in front of the liquid crystal drive unit. 5. The display section has an electrodeless region adjacent to an electrode region to which the display drive voltage is applied, and the electrodeless region has a transmittance corresponding to the display drive voltage. The battery pack according to claim 1, claim 2, claim 3 or claim 4, wherein density filters are stacked. 6. A small electronic device having a battery pack containing one or a plurality of secondary batteries as a driving power source, which is made of a reflective liquid crystal, and the information of the terminal voltage of the battery is displayed by the reflective liquid crystal. A small electronic device, comprising: a display unit for controlling the battery, and a driving unit that uses a voltage between terminals of the battery pack as a drive voltage and generates a display drive voltage from the drive voltage and supplies the drive voltage to the display unit. 7. The voltage dividing means for dividing the driving voltage applied from the one or a plurality of secondary batteries according to the voltage-transmittance characteristic of the reflective liquid crystal, and the voltage dividing means. 7. The small-sized electronic device according to claim 6, further comprising an oscillating means for alternatingly inverting the divided voltage thus generated and supplying it as the display drive voltage. 8. The drive means comprises an oscillating means for alternatingly inverting the drive voltage applied from the one or a plurality of secondary batteries, and an oscillation output of the oscillating means with respect to the voltage-transmittance characteristic of the reflective liquid crystal. 7. The small electronic device according to claim 6, further comprising: a voltage dividing unit that divides the voltage according to the above and outputs the driving voltage for display. 9. The small electronic device according to claim 6, wherein the display unit includes a booster unit in front of the liquid crystal drive unit. 10. The display section has an electrodeless region adjacent to an electrode region to which the display drive voltage is applied, and the electrodeless region has a transmittance corresponding to the display drive voltage. 10. The small electronic device according to claim 6, claim 7, claim 8 or claim 9, wherein density filters are stacked.