JP3675152B2 - Battery pack - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a battery pack used for a notebook computer, a mobile phone, a power tool, and a power assist bicycle, and more particularly to a battery pack that supplies power in response to a load with a large load current and a large current fluctuation such as a power assist bicycle. .
[0002]
[Prior art]
As shown in the block diagram of FIG. 2, the conventional battery pack 8 generally displays the remaining battery capacity by the number of lighted LEDs.
[0003]
FIG. 2 shows a battery block 2 in which a plurality of nickel-hydrogen storage batteries are connected in series, five LEDs 7 for displaying the remaining capacity of the battery block 2, and a circuit for calculating the remaining capacity of the battery block 2 and charging warning. It is a block diagram which shows the control circuit 3 and the apparatus main body 4 which consist of IC on a board | substrate.
[0004]
In the battery pack 8 and the device main body 4, the + terminal on the battery pack 8 side, the + terminal on the device main body 4 side, and the − terminal on the battery pack 8 side and the − terminal on the device body 4 side are electrically connected by a connector or the like. ing.
[0005]
Next, the operation of each circuit in FIG. 2 will be described below.
[0006]
The current from the battery block 2 flows through the load 5 and returns to the battery block 2 through the current detection resistor Ra. The voltage from the battery block 2 is supplied to the control circuit 3 through a smoothing circuit constituted by a resistor Rb and a capacitor C for removing noise of the device body 4 and a regulator circuit 6 for holding a constant voltage. And is supplied as a power supply voltage to the LED 7. The control circuit 3 is operated by the supplied voltage, and the LED 7 is lit.
[0007]
The voltage of the battery block 2 is divided by two resistors Rc and Rd so as to be input to the control circuit 3 and converted to a voltage level that can be input to the control circuit 3. The divided voltage is converted into digital data by the AD converter 31 and input to the voltage comparator 32. The voltage setting circuit 33b stores a preset discharge end voltage value of the battery. The voltage comparator 32 compares the battery voltage and the discharge end voltage. If the battery voltage becomes lower than the discharge end voltage, the battery voltage is charged. A request warning signal is sent to the LED controller 34b. When the LED controller 34b receives a charge request warning signal, the LED controller 34b blinks the LED 7 to inform the user of the time for charging.
[0008]
The voltage generated in the current detection resistor Ra is converted into digital data by the A / D converter 37 and sent to the remaining capacity calculator 38, where current accumulation calculation processing is performed, and the remaining capacity of the battery is calculated. . The remaining capacity of this battery is sent to the LED controller 34b. The LED controller 34b determines the number of LEDs 7 to be lit in proportion to the remaining capacity of the battery, and sends a signal to the LED 7. In response to this signal, the LED 7 displays the remaining battery capacity by the number of lighting of the LED 7.
[0009]
[Problems to be solved by the invention]
As described above, the smoothing circuit including the resistor Rb and the capacitor C has an effect of removing noise from the device body. In particular, the load of a device body such as a power assist bicycle often uses a digitally controlled motor, and this smoothing circuit is indispensable in order to prevent a remaining capacity calculation and display malfunction due to motor noise having a high frequency. Further, the power supply voltage supplied to the LED needs to be taken from the power supply line via the smoothing circuit and the regulator circuit from the viewpoint of making the light quantity of the LED constant. Further, in order to light a plurality of LEDs, a current of about 5 mA per LED is required. For this reason, in addition to the voltage drop of the battery block due to the resistor Rb, the LED is turned on to further drop the voltage of the battery block. Taking an example of a power-assisted bicycle in which this effect appears prominently, a battery with a heavy load, such as running on a slope, even when three of the four LEDs are lit, that is, when the remaining capacity of the battery is still sufficient. The battery voltage drops greatly due to the block. The battery voltage drop due to the three LEDs being lit is added to this. For this reason, the voltage of the battery block is lower than the voltage setting value for warning the battery to charge, and the LED may suddenly change from three lighting states to a flashing charge warning display. In this way, although there is a sufficient remaining battery capacity, a charging warning is displayed, so there is a problem that unnecessary charging is performed and the battery life is shortened.
[0010]
SUMMARY OF THE INVENTION The present invention solves the above-described problems, and an object of the present invention is to provide a battery pack capable of accurately displaying a warning requesting charging regardless of the number of lighting of remaining capacity display LEDs.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, the present invention comprises one or a plurality of secondary batteries, a plurality of LEDs for displaying remaining battery capacity, and a circuit board, and the remaining battery is controlled by a control circuit on the circuit board. The capacity is calculated, the remaining battery capacity is displayed in proportion to the number of LEDs lit by the output signal, and the LED is detected when the battery voltage falls below the preset discharge end voltage value Is a battery pack that displays a warning for charging request, and has a configuration in which the set value of the discharge end voltage is changed in accordance with the number of LEDs lit by a control circuit on the circuit board.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
The invention according to claim 1 of the present invention is the battery pack having the above-described configuration, and in particular, the control circuit on the circuit board changes the set value of the discharge end voltage according to the number of lighted LEDs.
[0013]
According to a second aspect of the present invention, the control circuit on the circuit board sets the discharge end voltage value of the battery in inverse proportion to the number of lighting of the LEDs.
[0014]
Thus, it is possible to accurately display a charge request warning display on the battery without being affected by the lighting display of the LED. Therefore, the user can charge the battery pack at the correct time, and can fully draw out the performance of the battery pack.
[0015]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
[0016]
FIG. 1 shows a block diagram of a battery pack 1 in an embodiment of the present invention. In FIG. 1, a battery pack 1 includes a battery block 2 composed of a plurality of nickel-hydrogen batteries, a control circuit 3 composed of ICs, a smoothing circuit composed of a resistor Rb and a capacitor C, a regulator circuit 6 and the remaining capacity of the battery. It is comprised from five LED7 which performs the charge warning display of a battery.
[0017]
The operation in the battery pack 1 will be described below.
[0018]
The voltage generated in the current detection resistor Ra is converted into digital data by the A / D converter 37 and sent to the remaining capacity calculator 38, where current accumulation calculation is performed to calculate the remaining capacity of the battery. The remaining capacity of this battery is sent to the LED controller 34a. The LED controller 34a determines the number of LEDs 7 to be turned on in proportion to the remaining capacity of the battery, and sends a signal to the LED 7. In response to this signal, the LED 7 displays the remaining battery capacity by the number of lighting of the LED 7.
[0019]
The battery voltage is divided by Rc and Rd, converted into digital data by the AD converter 31 and input to the voltage comparator 32. The voltage setting circuit 33a is a discharge end voltage value of the battery set in inverse proportion to the number of LED lighting (5, 4, 3, 2, 1 lighting) output from the LED controller 34a. Is stored, and the discharge end voltage is selected according to the number of LED lighting. For example, when the number of lighting of the LED 7 is 5 (the current value necessary for lighting is 25 mA), the battery discharge end voltage 3.3V is selected, and the number of lighting of the LED 7 is 3 (necessary for lighting). When the current value is 15 mA), the discharge end voltage of 3.5 V is selected.
[0020]
The discharge end voltage selected in this way is compared with the battery voltage at that time by the voltage comparator 32, and when the battery voltage becomes lower than the selected discharge end voltage, a warning signal for charge request is sent to the LED controller. 34a. When the LED controller 34a receives a warning signal for requesting charging, the LED controller 34a blinks the five LEDs 7 to notify the user of the timing of charging.
[0021]
【The invention's effect】
As described above, according to the present invention, in the battery pack that displays the remaining capacity using a plurality of LEDs, the set value of the discharge end voltage of the battery is changed according to the number of lighting of the LEDs by the control circuit on the circuit board. Thus, it is possible to accurately display a warning for charging request to the user without being affected by the lighting display of the LED. Therefore, the user can perform charging at the correct time when the charging request is issued, and can fully exhibit the performance of the battery pack.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a battery pack in an embodiment of the present invention. FIG. 2 is a block diagram showing a conventional battery pack.
1 Battery Pack 2 Battery Block 3 Control Circuit 4 Device Body 5 Load 6 Regulator Circuit 7 LED

Claims (2)

One or a plurality of secondary batteries, a plurality of LEDs for displaying a remaining battery capacity, and a circuit board are provided, the remaining capacity of the battery is calculated by a control circuit on the circuit board, and the output signal The remaining capacity of the battery is displayed in proportion to the number of lighting of the LED according to and when the battery voltage is detected to be less than or equal to a preset discharge end voltage value, a charging request is made by blinking the LED. The battery pack performs a warning display of the battery pack, wherein the control circuit on the circuit board changes the set value of the discharge end voltage in accordance with the number of lighting of the LEDs. The battery pack according to claim 1, wherein the control circuit on the circuit board sets a discharge end voltage value of the battery in inverse proportion to the number of lighting of the LEDs.

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