JPH1012283A - Battery pack and its control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a residual life of battery cell group in almost a fixed period, by detecting respective internal voltage value of each battery cell group, when the internal voltage value of a single battery cell is decreased to a discharge end voltage value, stopping operation of a battery pack. SOLUTION: At low power consumption mode time of a battery pack 1, a pack side CPU 12 is placed again in an operating condition from a standby condition, respective internal voltage of each battery cell 2A to 2D is detected in the pack side CPU 12. In this condition, when internal voltage of at least one battery cell 2A to 2D is decreased to a discharge end voltage value, D-FET 30 is controlled, supply of a DC current to an electronic equipment 5 is stopped. In addition to this operation, in the pack side CPU 12, a power down circuit 10 is controlled, all operations of the pack side CPU 12 are stopped. In this way, in the battery pack 1, a protection circuit 9 is switched from a low power consumption mode to a power down mode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[Table of Contents] The present invention will be described in the following order. Technical Field to which the Invention pertains Related Art Problems to be Solved by the Invention Means for Solving the Problems (FIG. 1) Embodiments of the Invention (FIG. 1) Effects of the Invention

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery pack and a method for controlling the battery pack, for example, a battery pack comprising a lithium ion battery as a secondary battery.
For example, the present invention is suitably applied to a battery pack for supplying a direct current to the electronic device by being loaded into an electronic device including a portable personal computer and a control method therefor.

[0003]

2. Description of the Related Art Conventionally, in a battery pack of this type, a battery cell group in which a plurality of battery cells are connected in series is housed therein, and a CPU (Cent
ral processor unit), a voltage measuring circuit, a current measuring circuit, a temperature sensor, a charge / discharge switching circuit, and a protection circuit in which an operation stop circuit is disposed at predetermined positions on a substrate.

In this case, in the protection circuit, a direct current is supplied from the battery cell group to the CPU, whereby the CPU operates to control the voltage measurement circuit, the current measurement circuit, and the temperature sensor, thereby controlling the terminal of each battery cell. A voltage value (hereinafter, referred to as a cell voltage value) is individually detected, and a charge / discharge current value and a temperature of a battery cell group are detected.

Here, in the battery cell, the cell voltage value is lower than the voltage value originally possessed by the battery cell (hereinafter referred to as the internal voltage value) due to the internal resistance thereof and the connection resistance of the CPU and the like connected thereto. And the load connected to the battery cell (the load of the electronic device)
Becomes larger, the cell voltage value shows a lower value. In addition, the cell voltage value fluctuates according to the operation status of a load (for example, a drive for rotating a floppy disk in an electronic device) connected to the battery cell.

Accordingly, in the protection circuit, the CPU detects the internal voltage value of each battery cell by correcting the cell voltage value of each battery cell based on the charge / discharge current value and the temperature.

In this way, in the protection circuit, when charging the battery cell group, the CPU monitors the internal voltage value of each battery cell, and when the internal voltage value of at least one battery cell reaches a predetermined voltage value. By controlling the charge / discharge switching circuit, a direct current supplied from the outside to the battery cell group is interrupted to stop charging the battery cell group. Thus, the protection circuit can protect each battery cell from overcharging.

In this protection circuit, in an operation mode in which a direct current is supplied from the battery cell group to the electronic device, the CPU detects the remaining capacity of the battery cell group based on the internal voltage value of each battery cell, and detects the detected remaining capacity. Send the capacity to the electronic device. Thereby, the electronic device monitors the input remaining capacity and stops the operation when the remaining capacity decreases to a predetermined value. Note that the electronic equipment normally performs at least a minimum required operation such as a data backup function even if the operation is stopped.

After that, the protection circuit stops the control of the voltage measurement circuit, the current measurement circuit, the temperature sensor, and the like by the CPU, and stops the CPU except for the minimum required operation, thereby putting the CPU into a standby state. Accordingly, the protection circuit reduces the discharge current value supplied from the battery cell group to the electronic device and the CPU (about several [μA] to several [mA]), and thus reduces the power consumption of the battery cell group. become.

In this low power consumption mode, although a small amount of direct current is supplied from the battery cell group to the electronic device and the CPU, etc.
Since the CPU does not monitor the internal voltage value of each battery cell, an operation stop circuit prevents overdischarge of each battery cell.

That is, the operation stop circuit measures a terminal voltage value (hereinafter, referred to as a total voltage value) of a battery cell group, and the measured total voltage value is a predetermined total voltage value (hereinafter, referred to as an operation stop voltage). Value, the input line for supplying a direct current from the battery cell group to the CPU is stopped to stop the operation of the CPU, and the charge / discharge switching circuit is controlled to control the direct current from the battery cell group to the electronic device. Stop supplying current. As a result, the protection circuit switches from the low power consumption mode to the power down mode in which the operation of the protection circuit is stopped, and can protect each battery cell from overdischarge.

[0012]

In the battery pack having such a configuration, the charge / discharge switching circuit of the protection circuit is constituted by an FET (Field Effect Transistor) or the like, and the charge / discharge switching circuit is used for input / output lines of a battery cell group. Is electrically cut off without being physically cut off. For this reason, in this battery pack, a small amount of leakage current (for example, several [μA]) is usually supplied from the battery cell group via the charge / discharge switching circuit in the power down mode.
Degree) is flowing.

That is, in the battery pack, the battery cell group is over-discharged and deteriorated by being left as it is after entering the power down mode. Therefore, in this battery pack, a remaining period in which the battery cell group can be recovered (that is, charged) without deteriorating the battery cell group immediately after switching to the power down mode is set as a remaining life, and the remaining life is fixed. Is set to

However, in this battery pack,
When the load (backup function) operated by the electronic device in the low power consumption mode is relatively large, the internal voltage value when the total voltage value of the battery cell group drops to the operation stop voltage value is relatively higher than the operation stop voltage value. When the load (back-up function) operated by the electronic device is relatively small, the internal voltage value when the total voltage value of the battery cell group drops to the operation stop voltage value is relatively small. It will be a close value.

Accordingly, the internal voltage value of the battery cell group immediately after switching to the power down mode has a different value according to the magnitude of the load (backup function) operated by the electronic device in the low power consumption mode. The life expectancy of the battery cells varies. That is, in this battery pack, there is a problem that it is difficult to stabilize the performance of the battery cell group because the remaining life of the battery cell group is affected by the size of the load (backup function) operated by the electronic device in the low power consumption mode.

Further, in this battery pack, the operation stop circuit operates in both the operation mode and the low power consumption mode. However, in this battery pack, when an electronic device connected thereto has a relatively large current load (drive or the like), the load of the electronic device operates in the operation mode,
A voltage drop may occur due to the internal resistance of the battery cell group, and the total voltage value of the battery cell group may be lower than the operation stop voltage value.

Therefore, in such a case, when the operation stop circuit detects that the total voltage value of the battery cell group has decreased to the operation stop voltage value in the operation mode, the supply of DC current to the operating electronic equipment is performed. And the electronic device breaks down.

Therefore, as a method of solving such a problem, a method of setting the operation stop voltage value detected by the operation stop circuit to a relatively low value when the electronic device has a relatively large current load. Conceivable.

However, in this method, the internal voltage value of the battery cell group immediately after switching from the low power consumption mode to the power down mode becomes extremely low, and as a result, the remaining life of the battery cell group is significantly shortened.
Therefore, in this method, the remaining life of the battery cell group is affected by the load of the electronic device connected to the battery pack, and there is a problem that it is difficult to stabilize the performance of the battery cell group.

Further, in this battery pack, the internal voltage value of the battery cell group is detected by the operation stop circuit in the low power consumption mode, and the mode is switched to the power down mode when the detected internal voltage value decreases to the predetermined internal voltage value. There is a method. However, in this case, it is necessary to configure the operation stop circuit with a CPU, a voltage measurement circuit, a current measurement circuit, a temperature sensor, and the like so as to detect the internal voltage value of the battery cell group. There was a problem that was complicated.

The present invention has been made in view of the above points, and it is an object of the present invention to propose a battery pack and a battery pack control method capable of stabilizing battery cell performance.

[0022]

According to the present invention, there is provided an internal voltage detecting means for detecting an internal voltage value for each battery cell, and an internal voltage detecting means for detecting an internal voltage value for each battery cell. In the low power consumption mode in the standby state in which the detection of the value is stopped, the terminal voltage value of the battery cell group or the terminal voltage value of each battery cell is measured, and the terminal voltage value of each battery cell group is set to the predetermined first terminal voltage. Starting means for activating the internal voltage detecting means when the internal voltage value has decreased to a predetermined value or when the terminal voltage value of the at least one battery cell has decreased to a predetermined second terminal voltage value; Of the internal voltage detecting means based on a control signal obtained from the internal voltage detecting means when the internal voltage has decreased to the first internal voltage value. The to be provided with a stop means for stopping.

In the present invention, the terminal voltage value of the battery cell group or the terminal voltage value of each battery cell is measured in the low power consumption mode in which the protection circuit formed on the substrate is in a standby state. When the terminal voltage value decreases to a predetermined first terminal voltage value, or when the terminal voltage value of at least one battery cell decreases to a predetermined second terminal voltage value, the protection circuit is activated to activate the protection circuit for each battery cell. A first step for detecting the internal voltage value and a second step for stopping the operation of the protection circuit when the internal voltage value of at least one battery cell decreases to a predetermined first internal voltage value. To

Therefore, according to the present invention, there is provided an internal voltage detecting means for detecting an internal voltage value for each battery cell, and a terminal voltage value of a battery cell group or each battery cell when the internal voltage detecting means is in a low power consumption mode. The terminal voltage value is measured, and when the terminal voltage value of each battery cell group decreases to a predetermined first terminal voltage value, or when the terminal voltage value of at least one battery cell decreases to a predetermined second terminal voltage value Activating means for activating internal voltage detecting means, and internal voltage detecting means based on a control signal obtained from the internal voltage detecting means when the internal voltage value of at least one battery cell drops to a predetermined first internal voltage value. And a stopping means for stopping the operation of the battery cell group. Gensa allowed can be made substantially constant period the remaining life expectancy by.

In the present invention, in the low power consumption mode,
The terminal voltage value of the battery cell group or the terminal voltage value of each battery cell is measured, and when the terminal voltage value of the battery cell group decreases to the first terminal voltage value, or when the terminal voltage value of at least one battery cell becomes the second terminal voltage value. When the internal voltage value of each battery cell decreases to a first internal voltage value, the protection circuit is activated when the internal voltage value decreases to the first internal voltage value. By stopping the operation of the electronic device in the low power consumption mode, it is possible to switch to the power down mode when the internal voltage value of the battery cell group becomes almost the same value without being affected by the operation state of the electronic device in the low power consumption mode. Thus, the variation in the remaining life of the battery cell group can be reduced, and the remaining life can be made substantially constant. That.

[0026]

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

In FIG. 1, a battery pack 1 houses a battery cell group 2 in which, for example, four battery cells 2A, 2B, 2C and 2D are connected in series.
The battery cell group 2 has a plus terminal for external connection (hereinafter referred to as a pack-side plus terminal) 3 on the plus side.
The negative side is connected to a negative terminal 4 for external connection (hereinafter referred to as a pack side negative terminal).

In this case, the battery pack 1 is
Of the electronic device 5 (hereinafter, referred to as a device-side positive terminal) 6 while the pack-side positive terminal 3 is connected to a loading portion (not shown). The negative terminal 4 on the pack side is connected to a negative terminal 7 for external connection of the electronic device 5 (hereinafter referred to as a negative terminal on the device side).

In addition to this, the battery pack 1
The pack-side plus terminal 3 is connected to the plus side of the power supply circuit 8 provided in the electronic device 5 via the device-side plus terminal 6, and the pack-side minus terminal 4 is connected to the power supply via the device-side minus terminal 7. It is connected to the negative side of the circuit 8. As a result, in the battery pack 1, a direct current is supplied from the battery cell group 2 to the electronic device 5, and
A direct current is supplied from the power supply circuit 8 of the electronic device 5 to the battery cell group 2 to be charged.

Here, in the battery pack 1,
A protection circuit 9 for protecting each of the battery cells 2A to 2D from overcharge and overdischarge is housed. In the protection circuit 9, an input terminal of a power down circuit (PD circuit) 10 is connected to the plus side of the battery cell group 2. The power down circuit 10 is supplied with a DC current from the battery cell group 2 and receives the DC current. The current is supplied to the internal voltage detector 11 from the output side.

In this case, the internal voltage detecting section 11 supplies a direct current supplied from the battery cell group 2 via the power down circuit 10 to a current input terminal (IN) 12A of a CPU (hereinafter referred to as a pack side CPU) 12. Supplied to As a result, the internal voltage detecting unit 11 is configured to
2 is operated, and the voltage measurement circuit 13, the current measurement circuit 14 and the temperature sensor 1 are controlled by the pack-side CPU 12.
5 is controlled.

The voltage measuring circuit 13 is composed of a line selector, an operational amplifier, and the like, and its input side is connected to a positive terminal and a negative terminal of each of the battery cells 2A to 2D. The voltage measurement circuit 13 individually measures the cell voltage value of each of the battery cells 2A to 2D, and uses each of the measured cell voltage values as a voltage value measurement signal S1 to connect a pack C connected to its output terminal.
The signal is sent to the analog-to-digital conversion terminal (A / D) 12B of the PU 12.

The current measuring circuit 14 includes an operational amplifier OP
And one input terminal of the operational amplifier OP and one end of the resistor R1 are connected to the minus side of the battery cell group 2, and the other input terminal of the operational amplifier OP is connected to the other input terminal of the operational amplifier OP. The other end of the resistor R1 is connected to the pack side minus terminal 4. The current measuring circuit 14 measures the charge / discharge current value of the battery cell group 2, and uses the measured charge / discharge current value as a current value measurement signal S2 to input the current value of the pack-side CPU 12 connected to the output terminal of the operational amplifier OP. Send it to terminal (I-IN) 12C.

The temperature sensor 15 is composed of a thermistor or the like, and one end thereof is connected between the minus side of the battery cell group 2 and one end of the resistor R1 of the current measuring circuit 14. The temperature sensor 15 measures the temperature of the battery cell group 2 and uses the measured temperature as a temperature measurement signal S3.
It is sent to the temperature input terminal (T-IN) 12D of the pack side CPU 12 connected to the other end.

Thus, the pack-side CPU 12 in the internal voltage detector 11 receives the input voltage value measurement signal S1,
Based on the current value measurement signal S2 and the temperature measurement signal S3, the cell voltage value of each battery cell 2A to 2D and the charge / discharge current value and temperature of the battery cell group 2 can be monitored. The pack side CPU 12
The internal voltage value of each of the battery cells 2A to 2D is detected based on each cell voltage value, charge / discharge current value, and temperature, and the remaining capacity of the battery cell group 2 is determined based on the internal voltage values obtained in this manner. It has been made to detect.

Here, in the pack-side CPU 12, the communication output terminal (T1) 12E is connected to an external communication output terminal (hereinafter, referred to as a pack-side external communication output terminal) 20 of the battery pack 1. , Communication input terminal (T
2) 12F is an external communication input terminal of the battery pack 1 (hereinafter referred to as a pack-side external communication input terminal) 2
1 connected.

In this case, the battery pack 1 is
In this state, the pack-side external communication output terminal 20 is connected to an external communication input terminal (hereinafter, referred to as a device-side external communication input terminal) 22 of the electronic device 5, and The pack-side external communication input terminal 21 is connected to an external communication output terminal (hereinafter referred to as a device-side external communication output terminal) 23 of the electronic device 5. The device-side external communication input terminal 22 and the device-side external communication output terminal 23 are connected to a CPU (not shown) provided in the electronic device 5 (hereinafter, referred to as a device-side CPU).

Thus, the pack-side CPU 12 sends the device-side C from the communication output terminal 12E through the pack-side external communication output terminal 20 and the device-side external communication input terminal 22 in this order.
The remaining capacity of the battery cell group 2 is sent to the PU as a capacity signal S4.

On the other hand, the device-side CPU sends a control signal S5 to the pack-side CPU 12 via the device-side external communication output terminal 23, the pack-side external communication input terminal 21, and the communication input terminal 12F as necessary. By doing so, various states such as the cell voltage value and the internal voltage value of each battery cell 2A to 2D and the charge / discharge current value and temperature of the battery cell group 2 are obtained from the pack side CPU 12 as the state signal S6. ing. Thus, the device-side CPU of the electronic device 5 can monitor various states of the battery cell group 2 of the battery pack 1 and / or each of the battery cells 2A to 2D.

Two FETs 30 and 31 are provided between the input terminal of the power-down circuit 10 and the pack-side plus terminal 3 to switch between charging and discharging of the battery cell group 2 under the control of the pack-side CPU 12. ing.

In practice, a discharge FET (hereinafter referred to as a D-FET) is connected to the input terminal of the power down circuit 10.
30 are connected to the drain (D) of the D-FE.
The source (S) of a charging FET (hereinafter referred to as a C-FET) 31 is connected to the source (S) of T30,
The drain (D) of the C-FET 31 is connected to the pack-side plus terminal 3.

A diode 3 is connected to the source of the D-FET 30.
0A is connected to the anode side and the DF
The cathode of the diode 30A is connected to the drain of the ET 30. Also, the source of the C-FET 31
The anode side of the diode 31A is connected and the drain of the C-FET 31 is connected to the diode 31A.
The cathode side of A is connected.

In this case, the pack-side CPU 12 first charges the C-FET control terminal (C-FE) when the battery cell group 2 is charged.
T) A control signal S10 is transmitted from 12G to a driver (hereinafter referred to as C-driver) 32. The C-driver 32 applies a control voltage V1 corresponding to the logic “H” level to the gate (G) of the C-FET 31 based on the input control signal S10, and turns on the C-FET 31. At this time, the D-FET 30 is off.

Thus, in battery pack 1,
The charging current supplied from the power supply circuit 8 of the electronic device 5 is a device-side plus terminal 6, a pack-side plus terminal 3, and a C-FET 3.
1, the battery 30A, the battery cell group 2, the pack-side minus terminal 4, and the device-side minus terminal 7 are successively energized, thus charging the battery cell group 2.

However, during charging, the pack-side CPU 12 monitors the cell voltage value of each of the battery cells 2A to 2D, the charging current value and the temperature of the battery cell group 2, and the internal voltage value of each of the battery cells 2A to 2D. Detect and monitor.

In this state, the pack-side CPU 12
Each of the battery cells 2A to 2D is preset to detect a predetermined internal voltage value (hereinafter, referred to as a charge termination voltage value) lower than an internal voltage value at which overcharging is performed, and at least one battery cell 2A is detected. Or when the 2D internal voltage value reaches the end-of-charge voltage value, the D-FET
A control signal (S11) is transmitted from a control terminal (D-FET) 12H to a driver (hereinafter referred to as a D-driver) 33, and a C-driver 3 is transmitted from a C-FET control terminal 12G.
2 to send a control signal S12.

The D-driver 33 controls the control voltage V according to the logic "H" level based on the input control signal S11.
2 is applied to the gate (G) of the D-FET 30,
The FET 30 is turned on. Further, the C-driver 32 applies a control voltage V3 corresponding to the logic “L” level to the gate of the C-FET 31 based on the input control signal S12 to turn off the C-FET 31. Thus, the protection circuit 9 can protect each of the battery cells 2A to 2D from overcharging.

On the other hand, in the pack-side CPU 12, in the operation mode, the D-FET
A control signal S11 is sent to the driver 33, and C-
The control signal S12 is sent from the FET control terminal 12G to the C-driver 32.

The D-driver 33 controls the control voltage V according to the logic "H" level based on the input control signal S11.
2 to the gate of the D-FET 30
30 is turned on. Further, the C-driver 32 applies a control voltage V3 corresponding to the logic “L” level to the gate of the C-FET 31 based on the input control signal S12 to turn off the C-FET 31.

In this state, in the battery pack 1, the D-FET 30, the diode 31 A, the pack-side plus terminal 3, the device-side plus terminal 6, the electronic device 5, the device-side minus terminal 7, and the pack-side minus terminal 4 from the battery cell group 2. A direct current can be supplied to the electronic device 5 by passing a discharge current through the path.

In the operation mode, the pack-side CPU 12 monitors the cell voltage value of each of the battery cells 2A to 2D, the discharge current value and the temperature of the battery cell group 2, and the internal voltage value of each of the battery cells 2A to 2D. Is detected and monitored. In addition to this, the pack side CP
U12 detects the remaining capacity of the battery cell group 2 based on the internal voltage value of each of the battery cells 2A to 2D, and sends the detected remaining capacity to the device-side CPU as a capacity signal S4.

The device-side CPU of the electronic device 5 monitors the remaining capacity of the battery cell group 2 in the course of discharging based on the input capacity signal S4, and switches the electronic device 5 when the remaining capacity decreases to a predetermined value. Only the minimum necessary functions such as the data backup function are operated, and most of the operations are stopped. Also, this device side CPU
Sends a stop signal S15 to the pack-side CPU 12 indicating that the operation of the electronic device should be stopped.

The pack-side CPU 12 detects that the operation of the electronic device 5 has stopped based on the input stop signal S15, stops the control of the voltage measurement circuit 13, the current measurement circuit 14, and the temperature sensor 15, and The CP on the pack side
U12 itself enters a standby state in which it stops operations other than the minimum required operation. As a result, the pack-side CPU 12 enters the low power consumption mode, and thus the protection circuit 9 enters the low power consumption mode.

Here, the protection circuit 9 is provided with a start-up voltage detection circuit 40.
The input terminal on the plus side is connected between the input terminal of the power down circuit 10 and the drain of the D-FET 30, and the input terminal on the minus side is connected to the other end of the resistor R1 of the current detection circuit 14. It is connected between the side minus terminal 4.

In this case, the starting voltage detecting circuit 40 measures the total voltage value of the battery cell group 2, and in this state, the total voltage value is, for example, each of the battery cells 2A to 2B.
When D falls to a value of about 11 to 12 [V] (hereinafter referred to as a starting voltage value) when each has a cell voltage value of about 2.75 to 3.0 [V], this is detected. It is set in advance.

Thus, the starting voltage detecting circuit 40
When detecting that the total voltage value has decreased to the starting voltage value, a detection signal S20 corresponding to a logic "L" level is output from its output terminal to the pack-side CPU based on the detection result.
12 to an interrupt terminal (INT) 12I.

The pack-side CPU 12 is activated based on the input detection signal S20 and is again in the operating state. The voltage measurement circuit 13, the current measurement circuit 14 and the temperature sensor 15 determine the cell voltage value of each of the battery cells 2A to 2D. The discharge current value and the temperature of the battery cell group 2 are measured individually and separately. In addition, the pack-side CPU 12 detects and monitors the internal voltage value of each of the battery cells 2A to 2D based on each cell voltage value, discharge current value and temperature.

In this state, the pack-side CPU 12
A predetermined internal voltage value higher than the internal voltage value at which each of the battery cells 2A to 2D becomes overdischarged (hereinafter referred to as a discharge end voltage value, and in this embodiment, for example, about 2.4 [V]) is detected. Is set in advance. Thus, when the internal voltage value of at least one of the battery cells 2A to 2D decreases to the discharge end voltage value, the pack-side CPU 12 sends the control signal S21 from the D-FET control terminal 12H to the D-driver 33. .

As a result, the D-driver 33 applies the control voltage V4 corresponding to the logic "L" level to the gate of the D-FET 30 based on the input control signal S21, and
-Turn FET 30 off. Thus, in the battery pack 1, the supply of the direct current to the electronic device 5 is all stopped.

At this time, the pack CPU 12 sends a power down signal S22 to the power down circuit 10 from the power down (PD) 12J. Power down circuit 1
In the case of 0, the DC current input line to the pack side CPU 12 is cut off based on the input power down signal S22, and the entire operation of the pack side CPU 12 is stopped. As a result, the pack-side CPU 12 switches from the low power consumption mode to the power down mode, that is, the protection circuit 9 also switches from the low power consumption mode to the power down mode.

Thus, in the battery pack 1, in the low power consumption mode, when the internal voltage value of at least one of the battery cells 2A to 2D decreases to the discharge termination voltage value in the protection circuit 9, the DC current flowing from the battery cell group 2 is reduced. Almost cut off (2 [μA] from D-FET 30)
Leakage current is less than or equal to
(A). When the internal voltage value of the battery cell group 2 always becomes almost the same value inside the protection circuit 9 without being affected by the operation state of the data backup function or the like in the electronic device 5. It can be switched to power down mode.

In this embodiment, the starting voltage detecting circuit 4
0 means that the total voltage value of the battery cell group 2 is constantly measured regardless of the operation mode and the low power consumption mode, and the start-up voltage value is detected in this state to transmit the detection signal S20 to the pack-side CPU 12. . However, in the pack side CPU 12, in the operation mode, the detection signal S
Even if 20 is input, normal operation is continued as in the above-described operation mode.

In the above configuration, in the battery pack 1, in the low power consumption mode, the pack CPU 12 is changed from the standby state to the operating state again, and
In this state, the internal voltage value of each of the battery cells 2A to 2D is detected, and when the internal voltage value of at least one of the battery cells 2A to 2D decreases to the discharge end voltage value in this state, the D-FET 30 is controlled. The supply of the direct current to the electronic device 5 is stopped. In addition to this, the power-down circuit 1
By controlling 0, all operations of the pack side CPU 12 are stopped. Thus, in the battery pack 1, the protection circuit 9 is switched from the low power consumption mode to the power down mode.

Therefore, in this battery pack 1,
The internal voltage value of each battery pack 2A to 2D is measured, and at least one battery cell 2A to 2B or 2B is measured.
By stopping the operation of the battery pack 1 when the internal voltage value of D drops to the discharge end voltage value, the inside of the battery cell group 2 is not affected by the operation status of the electronic device 5 such as the data backup function. It is possible to switch to the power-down mode when the voltage value always becomes substantially the same, and thus the variation in the remaining life of the battery cell group 2 can be reduced, and the remaining life can be made substantially constant.

In the battery pack 1, the starting voltage value (11 to 12) is detected by the starting voltage detecting circuit 40.
[V]) is a value that is relatively higher than the internal voltage value of, for example, about 9.6 [V] of the battery cell group 2 when the internal voltage value of each of the battery cells 2A to 2D becomes substantially the same as the discharge end voltage value. With this setting, even if the load of the data backup function in the electronic device 5 is relatively large and the total voltage value of the battery cell group 2 is lower than its internal voltage value, the pack-side CPU 12 is almost surely set. At least one battery cell 2
The power down mode can be switched when the internal voltage value of A to 2D decreases to the discharge end voltage value.

Therefore, in this battery pack 1,
Even when the load of the data backup function or the like in the electronic device 5 is relatively large, the remaining life of the battery cell group 2 can be greatly extended as compared with the remaining life of the battery cell group of the conventional battery pack.

Further, in the battery pack 1,
By controlling the D-FET 30 by the pack-side CPU 12 to stop the supply of the direct current from the battery cell group 2 to the electronic device 5, the electronic device 5 has a large current load, and the large current load is reduced. Even when the total voltage value of the battery cell group 2 is significantly reduced by the operation, the electronic device can be stopped as in the conventional battery pack to prevent the electronic device from being broken.

Further, in the battery pack 1,
By providing the power down circuit 10 and the starting voltage detection circuit 40 in addition to the internal voltage detection unit 11,
With a simple circuit configuration, the battery cell group 2 is not affected by the operation status of the data backup function or the like in the electronic device 5.
Can be switched to the power-down mode when the internal voltage value of each of them becomes almost the same value. As a result, the variation in the remaining life of the battery cell group 2 can be reduced, and the remaining life can be made substantially constant.

According to the above configuration, in the low power consumption mode, the total voltage value of the battery cell group 2 is measured, and when the measured total voltage value decreases to the starting voltage value, the starting voltage that outputs the detection signal S20 is output. A detection circuit 40;
When the detection signal S20 is input, the battery is activated to detect and monitor the internal voltage value of each battery cell 2A to 2D. In this state, the internal voltage value of at least one battery cell 2A to 2D is terminated. An internal voltage detection unit 11 that outputs a power-down signal S22 when the voltage drops to a voltage value; and an input line for direct current to the internal voltage detection unit 11 that is cut off by receiving the power-down signal S22. By providing the power-down circuit 10 for stopping the operation of the voltage detection unit 11, the variation in the remaining life of the battery cell group 2 can be reduced with a simple circuit configuration, and the remaining life can be made substantially constant. Thus, a battery pack capable of stabilizing the performance of a battery cell can be realized.

In the low power consumption mode, the total voltage value of the battery cell group 2 is measured, and when the measured total voltage value falls to the starting voltage value, the internal voltage detecting unit 1
1 and the internal voltage detector 11 detects the internal voltage value of each of the battery cells 2A to 2D,
In this state, at least one battery cell 2A
Or the operation of the electronic device 5 in the low power consumption mode by shutting off the DC current supply path to the internal voltage detection unit 11 when the internal voltage value of 2 to 2D decreases to the discharge end voltage value. The power-down mode can be switched when the internal voltage value of the battery cell group 2 always becomes almost the same value without being affected by the situation, thereby reducing the variation in the remaining life of the battery cell group 2 and reducing the remaining life. A battery pack control method that can keep the battery cell performance for a substantially constant period and thus stabilize battery cell performance can be realized.

In the above embodiment, the present invention is applied to a plurality of battery cells 2A to 2D comprising a lithium ion battery.
The present invention is not limited to this but is applied to the battery pack 1 in which the battery is stored. However, the present invention is not limited to the battery cells 2A to 2D, and may be, for example, a battery cell made of a nickel hydrogen battery or a battery cell made of a NiCd battery. Alternatively, the present invention may be applied to a battery pack in which various battery cells are stored.

In the above-described embodiment, a case has been described in which the battery cell group 2 formed by connecting four battery cells 2A to 2D in series is used. However, the present invention is not limited to this. May be used in series and / or in parallel.

Further, in the above embodiment, the total voltage value of the battery cell group 2 is measured by the starting voltage detecting circuit 40, and when the total voltage value decreases to the starting voltage value, a detection signal S20 is sent to the pack side CPU 12. However, the present invention is not limited to this, and the starting voltage detection circuit 40 measures the cell voltage value of each of the battery cells 2A to 2D and determines at least one battery cell 2A to 2D or 2D cell. When the voltage value decreases to a predetermined starting voltage value (for example, about 2.75 to 3.0 [V]), the detection signal S20 may be sent to the pack-side CPU 12 to be activated.

Further, in the above-described embodiment, the switching operation from the low power consumption mode to the power down mode of the present invention is performed when the electronic device 5 monitors the remaining capacity and the remaining capacity decreases to a predetermined value. A case has been described in which the operation is stopped and the protection circuit 9 is switched from the operation mode to the low power consumption mode. However, the present invention is not limited to this, and the electronic device 5 stops the operation by the user. In this case, or when the battery cell group 2 is discharged, the pack-side CPU 12 monitors the internal voltage value of each of the battery cells 2A to 2D, and the internal voltage value of at least one of the battery cells 2A to 2D decreases to the discharge end voltage value. When the supply of DC current from the battery cell group 2 to the electronic device 5 is stopped by the D-FET 30 when the When the electronic device 5 stops its operation due to various other situations, such as when the device 5 stops its operation, the electronic device 5 is applied to the protection circuit 9 switched from the operation mode to the low power consumption mode. Is also good.

Further, in the above-described embodiment, the case where the supply of the DC current to the pack-side CPU 12 is stopped by the power-down circuit 10 at the time of switching from the low power consumption mode to the power-down mode has been described.
The present invention is not limited to this, and the supply of the direct current to both the pack-side CPU 12 and the electronic device 5 may be stopped by the power-down circuit 10 when switching from the low power consumption mode to the power down mode. .

Further, in the above-described embodiment, the case where the internal voltage detecting section 11 is applied as the internal voltage detecting means for measuring the internal voltage value of each of the battery cells 2A to 2D has been described. Not limited to this, the point is that the cell voltage value of each of the battery cells 2A to 2D and the charge / discharge current value and the temperature of the battery cell group 2 are measured, and based on the cell voltage value, the charge / discharge current value and the temperature. As long as it can detect the internal voltage value of each of the battery cells 2A to 2D, the internal voltage detecting means for detecting the internal voltage value of each of the battery cells 2A to 2D may have various other configurations. Can be applied.

Further, in the above-described embodiment, when the internal voltage value of at least one of the battery cells 2A to 2D decreases to the discharge end voltage value, the internal voltage detecting unit 11
Has been described in the case where the power-down circuit 10 is applied as the stopping means for stopping the operation of the internal voltage detecting unit 11 based on the power-down signal S22 obtained from the above, but the present invention is not limited to this, As long as the supply of the DC current to the internal voltage detection unit 11 can be cut off by inputting the power down signal S22, various other configurations can be applied as the stopping means.

Furthermore, in the above-described embodiment, the total voltage value of the battery cell group 2 is in the low power consumption mode in the standby state in which the internal voltage detector 11 stops detecting the internal voltage value for each of the battery cells 2A to 2D. Alternatively, the cell voltage value of each of the battery cells 2A to 2D is measured, and when the total voltage value of the battery cell group 2 has decreased to a predetermined total voltage value, or when the cell voltage value of at least one battery cell 2A to 2D has reached a predetermined value. Although the description has been given of the case where the activation voltage detection circuit 40 is applied as activation means for activating the internal voltage detection unit 11 when the cell voltage value decreases to the cell voltage value described above, the present invention is not limited thereto.
In short, in the low power consumption mode, the total voltage value of the battery cell group 2 is measured, or the cell voltage value of each of the battery cells 2A to 2D is measured, and the total voltage value of the battery cell group 2 is reduced to a predetermined total voltage value. When it drops,
Alternatively, if the internal voltage detection unit 11 can be activated when the cell voltage value of at least one of the battery cells 2A to 2D decreases to a predetermined cell voltage value, the activation unit may have any of various other configurations. Can be applied.

Further, in the above-described embodiment, a case has been described in which the components other than the battery cell group 2 of the battery pack 1 shown in FIG. 1 are applied as the protection circuit 9, but the present invention is not limited to this. If the battery pack 1 that operates as described above can be configured by using the battery cell group 2 according to the embodiment, various other configurations can be applied as the protection circuit 9.

Further, in the above-described embodiment, a case has been described in which the battery pack 1 of the present invention is used as an electronic device in a portable personal computer. However, the present invention is not limited to this, and a video camera may be used as the electronic device. It may be used for various other electronic devices such as a mobile phone.

[0081]

As described above, according to the present invention, the internal voltage detecting means for detecting the internal voltage value of each battery cell, and the terminal voltage value of the battery cell group in the low power consumption mode of the internal voltage detecting means. Or, when the terminal voltage value of each battery cell is measured, and the terminal voltage value of each battery cell group decreases to a predetermined first terminal voltage value,
Alternatively, starting means for activating the internal voltage detecting means when the terminal voltage value of at least one battery cell decreases to a predetermined second terminal voltage value, and when the internal voltage value of the at least one battery cell is the predetermined first internal voltage And a stopping means for stopping the operation of the internal voltage detecting means based on a control signal obtained from the internal voltage detecting means when the voltage drops to a value, the variation in the remaining life of the battery cell group with a simple circuit configuration. , The remaining life can be made substantially constant, and a battery pack capable of stabilizing the performance of the battery cell can be realized.

In the low power consumption mode, the terminal voltage value of the battery cell group or the terminal voltage value of each battery cell is measured, and when the terminal voltage value of the battery cell group drops to the first terminal voltage value, or at least When the terminal voltage value of one battery cell drops to the second terminal voltage value, the protection circuit is activated to detect the internal voltage value of each battery cell, and then the internal voltage value of at least one battery cell becomes the first voltage value. By stopping the operation of the protection circuit when the voltage drops to the internal voltage value, the internal voltage value of the battery cell group always becomes almost the same value without being affected by the operation state of the electronic device in the low power consumption mode. Sometimes it is possible to switch to the power down mode, which reduces the variation in the remaining life of the battery cell group and The presence life expectancy substantially can be a period of time, thus the performance of the Batsuteriseru can realize a control method for stable may Batsuteripatsuku.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a battery pack according to the present invention.

[Explanation of symbols]

1 ... battery pack, 2 ... battery cell group, 2A,
2B, 2C, 2D: battery cell, 5: electronic equipment,
9 protection circuit 10 power down circuit 11
Internal voltage detecting section, 12: CPU on the pack side, 13: Voltage measuring circuit, 14: Current measuring circuit, 15: Temperature sensor, 40: Starting voltage detecting circuit.

Claims (4)

[Claims] 1. A battery pack in which a battery cell group including a plurality of battery cells is housed and is supplied to an electronic device by being loaded into the electronic device, wherein an internal voltage detection for detecting an internal voltage value for each of the battery cells is provided. And a terminal voltage value of the battery cell group or a terminal voltage of each battery cell in a low power consumption mode in a standby state in which the internal voltage detecting means has stopped detecting the internal voltage value for each battery cell. The terminal voltage value of each battery cell group decreases to a predetermined first terminal voltage value, or the terminal voltage value of at least one battery cell decreases to a predetermined second terminal voltage value. Activating means for activating the internal voltage detecting means when the battery voltage rises, and at least one battery Stopping means for stopping the operation of the internal voltage detecting means based on a control signal obtained from the internal voltage detecting means when the internal voltage value decreases to a predetermined first internal voltage value. Battery pack that features. 2. The internal voltage detecting means stops supply of the current to the electronic device when the internal voltage value of at least one battery cell decreases to the first internal voltage value. The battery pack according to claim 1. 3. A battery cell group comprising a plurality of battery cells and a substrate on which a protection circuit for protecting each of the battery cells from overcharging and overdischarging are housed and loaded in the electronic device, In the battery pack control method for supplying current to the battery, the terminal voltage value of the battery cell group or the terminal voltage value of each battery cell is set in a low power consumption mode in which the protection circuit formed on the substrate is in a standby state. Measuring the terminal voltage value of the battery cell group to a predetermined first terminal voltage value, or
A first step of activating the protection circuit and detecting an internal voltage value of each of the battery cells when the terminal voltage values of the two battery cells decrease to a predetermined second terminal voltage value; A second step of stopping the operation of the protection circuit when the internal voltage value of the battery cell decreases to a predetermined first internal voltage value. 4. In the second step, when the internal voltage value of at least one battery cell decreases to the first internal voltage value, the supply of the current to the electronic device is stopped. 4. The battery pack control method according to claim 3, wherein: