JPH10285826A - Battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a battery pack having an FG circuit to be driven by a power source other than the battery pack, when driven using this power source, by supplying a driving voltage to a remaining capacity detecting means from a higher voltage one out of a secondary battery and a power source. SOLUTION: A battery pack has an FG circuit and a power source battery 1 composed of a secondary battery inside a box, and besides has a positive electrode terminal 11, a negative electrode terminal 12, a temperature detecting terminal 13, a data communication terminal 14 and a power terminal 15 as external connecting terminals to be connected with a body apparatus. When an AC adapter is connected to the body apparatus and the power source battery 1 is in a charging state, the driving voltage of the FG circuit generated in a power circuit is supplied to a three-terminal regulator 3 through the power terminal and a diode 9, and the FG circuit is driven. If the power source battery is fully charged, the driving voltage generated by the power circuit is supplied to the three-terminal regulator 3, and the FG circuit is driven. Consequently, it becomes possible to make the secondary battery have a discharge time close to 100% of its potentially dischargeable time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery pack for a secondary battery used for electronic equipment such as a notebook personal computer, a portable telephone, a video camera, etc., and more particularly to a battery pack provided with a circuit for detecting the remaining amount of a secondary battery. About.

[0002]

2. Description of the Related Art Rechargeable batteries, such as nickel-cadmium batteries, nickel-metal hydride batteries, and lithium-ion batteries, that is, secondary batteries, are required to be compact and lightweight for notebook computers, mobile phones, video cameras, and the like. It is widely used as a power supply for equipment.

[0003] These secondary batteries are generally provided in the form of a battery pack incorporating various mechanisms in addition to the unit cells (cells). In particular, a battery pack for a notebook-type personal computer includes a battery pack. (Fue) for detecting
1 Gate) circuit is provided.

The FG circuit is configured using a microcomputer, and its basic function is to detect analog information such as voltage, current, and temperature of a unit cell and calculate the remaining amount of the unit cell from the information. Then, the result is converted into a digital signal and transferred to the main unit in which the battery pack is incorporated. As another function, the FG circuit may have a function of storing initial information such as a rated value of the battery pack and history information such as the number of times of charging and discharging (the number of cycles).

FIG. 4 shows an example of such a conventional battery pack. This battery pack has a positive terminal 51 and a negative terminal 52 for charging and discharging the unit cell 11,
A temperature detection terminal 54 and a data communication terminal 54 are provided. The microcomputer 42 detects the voltage value of the unit cell 41, detects the current value of the unit cell 1 via the shunt resistor 45 and the operational amplifier 47, and further detects the current value of the thermistor 44.
Is detected as a voltage change via the resistor 46, and the temperature information of the unit cell 41 is detected. Then, the remaining amount of the unit cell 11 is calculated based on the voltage value, the current value, and the temperature information, the value is converted into a digital signal, and the digital signal is output from the data communication terminal 54 to the CPU in the main unit (not shown). Further, the microcomputer 42 stores initial information such as a rated value of the battery pack and history information such as the number of times of charging and discharging of the unit cell 1 performed so far. These information are also stored in the data communication terminal 54, respectively. It is exchanged with the CPU in the main unit via the main unit. Here, the driving power of the FG circuit including the microcomputer 42 is generated from the voltage of the unit cell 11 by the three-terminal regulator 43.

As described above, in the conventional battery pack, the unit cell is used as a driving power source for the FG circuit. So, FG
In recent years, the power consumption of FG circuits has been reduced in order to avoid shortening the battery life due to the power consumption of the circuits. In particular, when the battery pack is removed from the main unit and left alone, the internal microcomputer is put to sleep to stop the communication function, and the analog information detection operation is kept to a minimum to minimize We try to minimize power consumption.

On the other hand, when the battery pack is incorporated in the main unit, the power consumption by the FG circuit increases because the detection of analog information and the data transfer to the main unit must be repeated frequently. However, conventionally, much effort has not been put into reducing the power consumption of the FG circuit in this state. This is because the capacity can be recovered by immediately recharging the battery using the AC adapter when the capacity of the unit cell is exhausted to some extent.

[0008]

As described above, in the conventional battery pack, even when the main unit is driven by a power source other than the unit cells, the power of the unit cells is consumed in the FG circuit. Therefore, when the main device is driven only by the battery pack, the battery is not in the fully charged state unless the battery is immediately after recharging, so that the capacity of the battery pack, that is, the discharge time of the battery, cannot always be exhibited 100%. There was a problem.

Further, in the method of recharging according to the decrease in the capacity of the unit cell, the unit cell is repeatedly recharged halfway, and when the unit cell is a nickel cadmium battery or a nickel hydride battery. There was also a problem that deterioration was accelerated by the memory effect.

According to the present invention, in order to solve such a problem, when a battery pack is incorporated in a main body device and the main body device is driven by a power source other than the battery pack, a battery for driving an FG circuit by this power source is provided. The purpose is to provide a pack.

[0011]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention is connected to a secondary battery, remaining amount detecting means for detecting the remaining amount of the secondary battery, and a power source other than the secondary battery. A power supply terminal and a power supply switching unit for supplying a drive voltage to the remaining amount detection unit from the higher voltage of the secondary battery and the power supply are provided.

Here, the power supply switching means includes a pair of diodes each having one end connected to the secondary battery and the power supply terminal and the other end commonly connected to the drive voltage input terminal of the remaining amount detection means. Is desirable.

In this case, if a power supply having a voltage higher than that of the secondary battery is connected to the power supply terminal, the remaining power detection means can be driven by the power supply, so that the capacity of the secondary battery is wasted. Never. Therefore, when the main unit is driven only by the secondary battery, the discharge time of the secondary battery can be constantly exerted at nearly 100%.

In addition, a decrease in the capacity of the secondary battery is suppressed,
Since the recharge interval is extended, deterioration due to the memory effect is not accelerated even when the secondary battery is a nickel cadmium battery or a nickel hydride battery.

Another aspect of the present invention is a battery pack connected to a main unit having a power supply circuit for generating a power supply voltage from one of a secondary battery and a power supply other than the secondary battery. A remaining amount detecting means for detecting the remaining amount of the secondary battery, a power supply terminal connected to a power supply circuit when a battery pack is connected to the main device, and determining whether the main device is connected to the battery pack, When the main unit is not connected, the driving voltage is supplied from the secondary battery to the remaining amount detecting unit. When the main unit is connected, the driving voltage is supplied from the power supply circuit connected to the power terminal to the remaining amount detecting unit. Power supply switching means for supplying power.

In this case, if the battery pack is connected to the main unit, the remaining voltage detecting means is driven by the driving voltage from the power supply circuit of the main unit, so that the power consumption of the secondary battery can be suppressed. Also, when the battery pack is removed from the main unit, the power supply of the remaining amount detecting means is immediately switched to the secondary battery, so that the voltage supply to the remaining amount detecting means is not interrupted, and the remaining amount detecting means is always stable. Can be operated.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 is a diagram showing a circuit configuration of a battery pack according to a first embodiment of the present invention. In this battery pack, a unit cell 1 composed of a secondary battery and an FG
And a positive terminal 11 and a negative terminal 1 as external connection terminals to be connected to a main body device to be described later.
2. It has a temperature detection terminal 13, a data communication terminal 14, and a power supply terminal 15. The FG circuit mainly includes the microcomputer 2 and further includes a three-terminal regulator 3, a thermistor 4, a shunt resistor 5, a resistor 6, and an operational amplifier 7 in combination. The diodes 8 and 9 are selectively connected to the microcomputer 2 via the three-terminal regulator 3 as a drive power supply by selectively switching the higher voltage of the external power supply connected to the unit cell 1 or the power supply terminal 15 as described later. And a switching circuit for performing the switching.

The positive electrode of the unit cell 1 is connected to a positive terminal 11, the negative electrode is connected to a negative terminal 12 via a shunt resistor 5, and these positive and negative electrodes are further connected to the microcomputer 2. The shunt resistor 5 is for detecting the current of the unit cell 1,
Each input terminal of the operational amplifier 7 is connected to both ends thereof, and the output terminal of the operational amplifier 7 is connected to the microcomputer 2.
One end of the microcomputer 2 is grounded together with the negative terminal 12.

The thermistor 4 is a temperature detecting element for detecting the temperature of the battery pack, particularly the temperature of the unit cell 1,
One end is connected to the temperature detection terminal 13 and one end of the resistor 6, and the other end is connected to the negative terminal 12. The other end of the resistor 6 is connected to the microcomputer 2. The resistance of the thermistor 4 changes as the temperature of the unit cell 1 changes.

The anode of the diode 8 is connected to the positive terminal 11, the anode of the diode 9 is connected to the power supply terminal 15, and the cathodes of these diodes 8 and 9 are commonly connected to the input terminal of the three-terminal regulator 3. I have. The output terminal of the three-terminal regulator 3 is connected to the microcomputer 2, and the other end is grounded. As will be described later, the three-terminal regulator 3 is operated by the supply voltage from the higher voltage of the unit cell 1 and the power supply circuit of the main unit.
A drive voltage for the G circuit is generated. Hereinafter, the voltage of the positive terminal 11 with respect to the ground point is referred to as V _A , and the voltage of the power supply terminal 15 is referred to as V _B.

The microcomputer 2 calculates the remaining amount of the unit cell 1 according to a preset program. Specifically, the microcomputer 2 detects the voltage value of the unit cell 1, detects the current value of the unit cell 1 via the shunt resistor 5 and the operational amplifier 7, and further detects the change in the resistance value of the thermistor 4 via the resistor 6. The temperature information of the unit cell 1 is detected by detecting the change as a voltage change. The microcomputer 2 calculates the remaining amount of the unit cell 1 based on the voltage value, the current value, and the temperature information, converts the value into a digital signal, and outputs the digital signal from the data communication terminal 14 to a CPU in a main unit described later. I do.
At this time, the data line up to the data communication terminal 14 may be a single wire type or a double wire type, and the communication system may be one-way or two-way.

When the battery pack is detached from the main unit and left alone, the microcomputer 2 goes into a sleep state, stops the communication function, and minimizes the operation of detecting analog information to minimize the unit cell. 1) minimize power consumption. Further, the microcomputer 2 is provided with a function of storing initial information such as a rated value of the battery pack and history information such as a cumulative number of times of charging and discharging of the battery pack, a so-called cycle number. Note that these information are also stored in the data communication terminal 14.
Is exchanged with the CPU in the main unit via the.

On the other hand, FIG. 2 is a diagram showing a configuration of a power supply unit of a main unit such as a notebook type personal computer in which the battery pack is incorporated. As shown in FIG. 1, the positive terminal 11, the negative terminal 12, the temperature detecting terminal 13, the data communication terminal 14, and the power terminal 15 of the battery pack shown in FIG. A detection terminal 23, a data communication terminal 24, and a power supply terminal 25 are provided.

The power supply circuit 31 generates at the time of connection of the AC adapter (not shown) and a drive voltage V _cc of the main device from the DC voltage obtained by this AC adapter, the driving voltage of the charging voltage and FG circuit of the unit cell 1 Output from the positive-side input / output terminal V +, and when the AC adapter is not connected, the unit cell 1 of the battery pack passes through the positive terminal 21 and the negative terminal 22.
A drive voltage _Vcc for the main device is generated by the voltage supplied from.

The positive side input / output terminal V + of the power supply circuit 31
Is connected to the positive terminal 21 via the switch SW1, the negative input / output terminal V− is connected to the negative terminal 22, and the reference potential terminal is grounded.

The switch SW1 is a switch for controlling charging of the battery pack. The switch SW1 is turned on / off by the CPU of the main unit, and is turned on when the battery pack is charged. When the battery should not be charged, it is turned off.

The positive side input / output terminal V + of the power supply circuit 31
Further, it is connected to the power supply terminal 25 and one end of the resistor 32. The other end of the resistor 32 is connected to one end of the switch SW2, and the other end of the switch SW2 is connected to the temperature detection terminal 23. The switch SW2 is turned on when the battery pack is normally fixed to the main device and the fastener is set, in conjunction with the operation of a physical fastener for incorporating the battery pack into the main device. Is turned off when the device is removed from the main device and the fastener is removed.

The data communication terminal 24 is connected to a CPU of a main unit (not shown). Hereinafter, a case where the battery pack shown in FIG. 1 and the main body device having the power supply unit shown in FIG. 2 are used in combination will be described in detail.

First, when the battery pack is detached from the main unit and left alone, the voltage V
_Since the relationship between _A and the voltage V _B of the power supply terminal 15 is V _A > V _B = 0, the voltage of the unit cell 1 is supplied to the three-terminal regulator 3 via the conducting diode 8 and the FG circuit including the microcomputer 2 Is generated. At this time, since no current flows through the thermistor 4 and the resistor 6, the temperature information detected by the microcomputer 2 becomes Low level.
In this case, the microcomputer 2 determines that the battery pack is left alone, puts itself into a sleep state to stop the communication function, and minimizes the operation of detecting analog information.

Next, when the battery pack is attached to the main device, the switch SW2 is turned on. At this time, as will be described later, current flows through the thermistor 4 and the resistor 6 via the resistor 32 and the switch SW2 by the supply voltage from either the unit cell 1 or the power supply circuit 31, so that the temperature detected by the microcomputer 2 The information becomes High level. In response to this, the microcomputer 2 returns from the sleep state and performs various processes such as detection of analog information, calculation of the capacity of the unit cell 1, and data communication.

When the battery pack is attached to the main unit, the unit 1 or the power supply circuit depends on the charging state of the unit cell 1 of the battery pack and the connection state of the AC adapter to the main unit as described below. 31 drives the FG circuit. Incidentally, the fact switching of driving power of the FG circuit is performed by switching circuit consisting of a diode 8 and 9 operates in response to the relationship between the voltage V _B of the voltage V _A and the power supply terminal 15 of the positive electrode terminal 11 .

First, when an AC adapter is connected to the main unit and the unit cell 1 is in a charged state, the switch S
W1 becomes V _A = V _B turned on. Therefore, the drive voltage of the FG circuit generated by the power supply circuit 31 is
The FG circuit is supplied to the three-terminal regulator 3 via 5, 5 and the diode 9, and the FG circuit is driven by the three-terminal regulator 3 accordingly.

When the cell 1 is fully charged, the switch SW1 is turned off. At this time, V _A <V _B
Therefore, the driving voltage generated by the power supply circuit 31 is supplied to the three-terminal regulator 3 as in the case described above, and the FG circuit is driven by the three-terminal regulator 3 accordingly. When V _A > V _B , the FG circuit is driven by the unit cell 1 as in the case where the battery pack is left alone.

When the AC adapter is removed from the main unit, the main unit is driven by the battery pack. In this case, although the same V _A = V _B at the time of charging battery cell 1 in turn is supplied to the three-terminal regulator through the discharge voltage diode 8 of the cell 1, FG circuit is driven. The discharge voltage of the unit cell 1 is supplied to the power supply circuit 31 via the diode 34, and the power supply circuit 31 generates a drive voltage _Vcc for the main device based on the discharge voltage.

As described above, in the battery pack of this embodiment,
Two drive power supplies, a unit cell 1 and a power supply circuit 31 (AC adapter connection), are provided for the FG circuit, and diodes 8 and 9
The driving voltage is supplied to the FG circuit from the higher voltage by using the switching circuit composed of

As a result, when the battery pack is incorporated in the main unit and the power supply circuit of the main unit generates the drive voltage of the main unit by the DC voltage supplied from the AC adapter, the power supply circuit drives the FG circuit. A voltage is also generated. Therefore, unlike the conventional case where the FG circuit is always driven by the unit cells, the capacity of the unit cells is not wastefully consumed. It is possible to always exert a discharge time of nearly 100%.

Further, since the decrease in the capacity of the unit cell is suppressed, the interval of recharging of the unit cell is extended as compared with the conventional case, so that even if the unit cell is a nickel cadmium battery or a nickel metal hydride battery, the deterioration due to the memory effect occurs. Will not be hastened.

(Second Embodiment) FIG. 3 shows a second embodiment of the present invention.
It is a figure showing the circuit composition of the battery pack concerning an embodiment. In the following, portions corresponding to those in FIG. 1 are denoted by the same reference numerals, and the description will be focused on differences from the first embodiment. Also, the main unit shown in FIG. 2 is used as it is.

In the battery pack of this embodiment, the drive power of the FG circuit is switched by a switch. That is, in this battery pack, the switch SW3 is used instead of the diodes 8 and 9 shown in FIG. The A terminal of the switch SW3 is connected to the positive terminal 11, the B terminal is connected to the power supply terminal 15 via the diode 17, and the common terminal is connected to the input terminal of the three-terminal regulator 3. The anode of the diode 17 is connected to the power supply terminal 14, and the cathode is connected to the B terminal of the switch SW3. Note that the diode 17 is for preventing backflow, and is not necessarily provided.

The microcomputer 16 has a function of controlling the switching of the switch SW3 in addition to the function of the microcomputer 2 described with reference to FIG. 1, and a signal output terminal is connected to a switching control line 18 for the switch SW3. .

The switch SW3 is switched by the microcomputer 1
6 is performed according to the Low / High level of the temperature information detected in 6. That is, when it is determined that the temperature information is at the Low level and the battery pack is not attached to the main device, the switch SW3 is switched to the A terminal side, and the FG circuit is driven by the voltage supplied from the unit cell 1. .

On the other hand, when the temperature information is at the high level,
When it is determined that the battery pack is attached to the main device, the switch SW3 is switched to the terminal B side. At this time, if an AC adapter is connected to the main unit, A
Power supply circuit 3 according to DC voltage supplied from C adapter
The drive voltage generated in 1 is supplied to the three-terminal regulator 3 via the power supply terminals 25 and 15, the diode 17, and the switch SW3. If the AC adapter is not connected to the main device, the discharge voltage of the unit cell 1 is supplied to the three-terminal regulator 3 via the positive terminals 11, 21, the diode 34, the power terminals 25, 15, the diode 17, and the switch SW3. Then, the FG circuit is driven.

When the battery pack is removed from the main unit, the switch SW2 is turned off when the battery pack is released from the main unit, and the temperature information shifts from the high level to the low level in response to this. The switch SW is operated by the microcomputer 16 detecting this.
3 is switched from the B terminal side to the A terminal side.

As a result, it is possible to switch the driving power source of the FG circuit to the unit cell 1 before actually removing the battery pack from the main device and disconnecting the connection terminals 11 to 15 and 21 to 25. Therefore, when the battery pack is removed from the main device, the power supply to the three-terminal regulator 3 is not interrupted, and the FG circuit can be driven stably. As described above, the first and second embodiments have been described as examples, but the present invention is not limited to the above embodiment, and can be implemented with various modifications.

[0045]

As described above, according to the present invention, the remaining amount detecting circuit can be driven by a power source other than the secondary battery by the battery pack, so that the capacity of the secondary battery is wasted. And when the main unit is driven by the battery pack, the discharge time of the secondary battery can be constantly exerted at almost 100%.

Further, since the reduction in the capacity of the secondary battery is suppressed, the interval between recharges is extended as compared with the prior art.
Even when the secondary battery is a nickel-cadmium battery or a nickel-metal hydride battery, deterioration due to the memory effect is not accelerated.

Further, when the battery pack is removed from the main unit, the power supply of the remaining amount detecting circuit is immediately switched to the secondary battery, so that the voltage supply to the remaining amount detecting circuit is not interrupted and the remaining amount is always stably maintained. The quantity detection circuit can be operated.

[Brief description of the drawings]

FIG. 1 is a diagram showing a circuit configuration of a battery pack according to a first embodiment of the present invention.

FIG. 2 is an exemplary view showing a circuit configuration of a power supply unit of a main device into which the battery pack of the embodiment is incorporated.

FIG. 3 is a diagram showing a circuit configuration of a battery pack according to a second embodiment of the present invention.

FIG. 4 is a diagram showing a circuit configuration of a conventional battery pack.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Unit cell 2, 16 ... Microcomputer 3 ... Three terminal regulator 4 ... Thermistor 5 ... Shunt resistance 6, 32 ... Resistance 7 ... Operational amplifier 8, 9, 17 ... Diode 11, 21, ... Positive terminal 12, 22, ... Negative terminal 13, 23: Temperature detection terminal 14, 24: Data communication terminal 15, 25: Power supply terminal 18: Switching control line 31: Power supply circuit SW1, SW2, SW3: Switch

Claims (3)

[Claims] A rechargeable battery; a remaining amount detecting means for detecting a remaining amount of the rechargeable battery; a power supply terminal connected to a power supply other than the rechargeable battery; A battery pack comprising: a power supply switching unit that supplies a drive voltage to the remaining amount detection unit from a higher voltage. 2. The power supply switching means includes a pair of one end connected to the secondary battery and the power supply terminal, and the other end connected in common to a drive voltage input terminal of the remaining amount detection means. 2. The battery pack according to claim 1, comprising a diode. 3. A battery pack connected to a main unit having a power supply circuit for generating a power supply voltage from one of a secondary battery and a power source other than the secondary battery, comprising: a secondary battery; Remaining power detection means for detecting the remaining power; a power terminal connected to the power supply circuit when the battery pack is connected to the main device; and determining whether the main device is connected to the battery pack. When the main device is not connected, a driving voltage is supplied from the secondary battery to the remaining amount detecting means, and when the main device is connected, the remaining voltage is supplied from the power supply circuit connected to the power terminal. A battery pack comprising: a power supply switching unit that supplies a drive voltage to a detection unit.