JP2001251770A - Rechargeable battery or rechargeable battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rechargeable battery and a rechargeable battery pack including a charger controller, which can prevent improper charging, without having to control with a processor with a power-on reset function. SOLUTION: A control circuit is formed with a gate control circuit in place of a processor for program operation and a charging acknowledgment circuit for turning on a switch circuit by receiving a signal from the outside of a rechargeable battery is provided to such switch circuit, which is turned off when the voltage is lower than the operating voltage of the gate control circuit. Thereby, it is no longer required to execute the power-on reset processing and improper charging can be prevented by impeding over-charging and over- discharging. Accordingly, a part for storing the record information of application environment obtained with various sensors can be isolated from the charging discharging control circuit, and thereby the environment record information is protected from erasure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rechargeable battery or a rechargeable battery pack, and more particularly, to a lithium ion secondary storage battery (hereinafter referred to as a lithium battery) having a charge controller or a processor having a power-on reset in the rechargeable battery pack. Without having to control
The present invention relates to a rechargeable battery and a rechargeable battery pack having a charge controller capable of preventing unauthorized charging.

[0002]

2. Description of the Related Art Conventionally, a lithium battery or the like is charged with a constant current at first, assuming that the storage battery is in a discharged state, and then charged substantially and then almost fully charged. The charging mode is switched to the constant-voltage charging mode when the charging voltage becomes lower.When the charging current falls below the predetermined value or the charging voltage becomes higher than the predetermined value under this constant-voltage charging, the charging is sufficiently performed. Control is performed to turn off the switch and terminate charging assuming that the charging has been performed. A charge control controller (or a part thereof) is built in or integrated with the lithium ion battery or its rechargeable battery pack side to prevent overcharge.

[0003] Rechargeable batteries and rechargeable battery packs of this type (hereinafter referred to as rechargeable batteries) are incorporated in electronic devices such as portable computers and hand-held electronic devices. When the voltage of the rechargeable battery drops below a predetermined value, the electronic devices are recharged. The charging is performed by the charging circuit on the side, the charging current is received, the charging is terminated when the charging is completed, and the discharging is performed to supply power to the electronic device when the battery is driven. For this purpose, the controller of the charging control switches the current direction by providing a relay or a relay device that allows current to flow bidirectionally between the positive electrode side of the rechargeable battery and the charging terminal. In addition, there is a diode switching circuit that inserts a diode in series in each of the charging and discharging directions to select a current in one direction and block a current in the opposite direction. In an electronic device having this type of rechargeable battery, when the electronic device is connected to an AC power supply and the electronic device is not operating or is operating, the rechargeable battery is charged and the AC power supply is removed. When the electronic device is operated by operation, the electronic device is operated by electric power from the rechargeable battery. In recent years, batteries conforming to the smart battery standard have been developed and used as batteries built in electronic devices. In this smart battery standard, a processor (M
PU) and a control circuit having a processor provided in the rechargeable battery are connected to transmit the state of the battery as data to a processor (MPU) in the electronic device.

[0004]

As the above-mentioned controller, there is a controller that incorporates a processor such as a CPU or an MPU and controls charging by a program operation. However, if the processor malfunctions or hangs up, There is a problem that normal charge control is not performed. In the low voltage state where the power supply voltage is lower than the operating voltage of the processor,
Since charge control cannot be performed, a circuit such as a resistor for securing the operating power supply voltage of the processor must be inserted in the charge / discharge line, which causes an increase in power consumption. Further, in the case of charge control by the processor, in the case of a hang-up in a low voltage state lower than the operating voltage or when replacing a defective battery body, a power-on reset for returning to the initial state and restarting operation is performed. There is a need. When this power-on reset is performed, the memory that records the environmental history in charge control is reset, and the connection circuit abnormality, abnormal overvoltage, abnormal extremely low temperature, abnormal high temperature, abnormal low voltage that is collected by various sensors as the environmental history , Abnormal high pressure, abnormal shock, abnormal current, use frequency management, radiation irradiation,
Even detection information such as flammable gas detection and corrosive gas detection is reset, and there is no point in mounting various sensors on a rechargeable battery or a battery pack. An object of the present invention is to solve such a problem of the related art, and a charge battery having a charge controller capable of preventing unauthorized charge without performing control by a processor having a power-on reset. And a rechargeable battery pack.

[0005]

A rechargeable battery or a rechargeable battery pack according to the present invention for achieving the above object is connected to a battery body and a load connected to a charging circuit or supplying power. A charge / discharge power supply line, a switch circuit connected in series between the charge / discharge power supply line and the battery body, and detecting that the voltage of the positive terminal of the battery body is equal to or higher than a predetermined voltage exceeding the full charge voltage. A first detection signal to generate a second detection signal by detecting that the voltage of the positive terminal of the battery body is equal to or lower than a predetermined voltage for preventing overdischarge; When the voltage exceeds a predetermined voltage for preventing overdischarge and falls within a range of not more than a full voltage, the switch circuit is set to the ON state, and when the first detection signal is received and the second detection signal is received. Switch circuit A gate control circuit for turning off the battery; and a charge permission circuit for receiving a signal from outside the rechargeable battery to turn on the switch circuit. The voltage on the positive electrode side is lower than the operating voltage of the gate control circuit. Sometimes, the switch circuit is turned off, and the voltage detection circuit and the gate control circuit receive power from the battery body and operate.

In another aspect of the present invention, a first switch circuit including a switch in which a diode in a forward direction with respect to a charging direction is connected in parallel and a diode in a forward direction with respect to a discharging direction are connected in parallel. And a second switch circuit comprising a switch connected to the first and second switch circuits. The charge and discharge power supply line and the battery body are connected so that the diodes of the first and second switch circuits are in opposite directions to each other. A current detection circuit for detecting a charge current value and a discharge current value is provided in series between the positive electrode and a positive electrode side; at least at the time of charging, a switch of a second switch circuit is turned on; When the voltage on the side exceeds a predetermined voltage for preventing overdischarge and the discharge occurs, the switch of the first switch circuit is set to the ON state, and the current detection circuit The switches of the first and second switch circuits are selectively turned on / off by the gate control circuit in response to the detection signal. This is protected by a switch.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As described above, the control circuit is constituted by a gate control circuit instead of a program operation processor, and a switch circuit which is turned off when the operating voltage of the gate control circuit is lower than the operating voltage of the charge battery. By providing a charge permission circuit that turns on this switch circuit in response to an external signal, power-on reset processing is not required, and overcharging and overdischarging are prevented to prevent unauthorized charging. be able to. As a result, the portion for storing the usage environment history information collected by the various sensors can be separated from the charge / discharge control circuit, and the environment history information does not need to be erased. In particular, in the configuration of the other invention described above, in the charging state, the switch of the second switch circuit having the diode in the opposite direction to the charging is set to the ON state as its initial state, Is charged via a forward diode in parallel with the switch circuit.
Then, when the charging current value becomes equal to or more than a predetermined value, the switch of the first switch circuit is turned on, and the charging is performed without reducing the voltage drop without passing through a diode. As a result, heat radiation due to the charging current can be reduced, and unnecessary power consumption can be suppressed.

On the other hand, at the time of discharging for supplying electric power to the device, the switch of the first switch circuit having a diode in the opposite direction to the discharging is set to an initial discharge state, and the voltage on the positive electrode side of the battery body is exceeded. When the voltage exceeds a predetermined voltage for preventing discharge, the switch is turned on, and discharge is performed via a forward diode parallel to the second switch circuit. Then, when the discharge current value becomes equal to or more than a certain value, the switch of the second switch circuit is turned on and the discharge is performed without reducing the voltage drop without passing through a diode. This makes it possible to reduce heat radiation due to the discharge current, and to suppress unnecessary power consumption. Furthermore, when performing the overcharge prevention operation,
A gate control circuit turns off a switch of a second switch circuit by a gate control circuit in response to a first detection signal of the voltage detection circuit, and performs an overdischarge prevention operation in response to a second detection signal of the voltage detection circuit. Thereby turning off the switch of the first switch circuit.

As a result, heat generation is suppressed, power efficiency is improved, and efficient charge / discharge and overcharge control for a rechargeable battery are achieved.
A rechargeable battery and a rechargeable battery pack having a charge controller capable of overdischarge control can be realized. In addition,
In the above case, when the voltage on the positive electrode side of the battery body is a predetermined voltage for preventing overdischarge or within a range from a predetermined voltage exceeding this to a predetermined voltage equal to or lower than a full voltage, that is, when the battery It is preferable that the switches of the first and second switch circuits are both set to the ON state when the operation range is within the range of, so that charging and discharging by the diode are not performed regardless of the charging current value and the discharging current value. As a result, heat generation during normal operation can be suppressed.

[0010]

FIG. 1 is a circuit diagram mainly showing a lithium rechargeable battery built in an electronic apparatus according to an embodiment to which the rechargeable battery of the present invention is applied, and FIG. 2 is a diagram for explaining a structure for returning from an unused state. FIG. In FIG. 1, reference numeral 20 denotes an electronic device, which has a rechargeable battery 10 having an in-battery charge control circuit detachably mounted therein. The rechargeable battery 10 has a plurality of serially connected lithium battery cells (hereinafter referred to as a battery main body) 1a to 1n. The power supply circuit 22 provided in the apparatus main body 21 supplies a charge / discharge terminal 8a, a charge / discharge power supply line + Vcc ( In the following, a charging current is received via a power supply line + Vcc), and the apparatus main body 21 is supplied with power by a discharging current from the battery main body side via a charging / discharging terminal 8a. In addition, the battery state detection circuit 23 provided in the apparatus main body 21 of the rechargeable battery 10 detects an impedance value indicating whether or not the battery can be charged via the detection terminal 9a.

On the other hand, a sensor section 11 such as a temperature detecting section is provided inside the rechargeable battery 10, and receives a signal from each sensor (not shown) to store a state thereof, Further, a state reading circuit 13 is provided.
The state reading circuit 13 is connected to a processor (MPU) 24 in the apparatus main body via the SM bus 13a according to, for example, the smart battery standard, and the contents detected by various sensors are sent to or read from the MPU 24 as data. The temperature detecting section of the sensor section 11 detects an extremely low temperature, an abnormally high temperature, and the like. In addition, the detection target of the sensor unit 11 detects connection circuit abnormality, abnormal overvoltage, abnormal low voltage, abnormal high pressure, abnormal shock, abnormal current, use frequency management, radiation irradiation, flammable gas detection, corrosive gas detection, and the like. Sensors may be provided, or any of them may be provided, or many of them may be provided.

The power supply circuit 22 includes a rechargeable battery 10 and a commercial AC
It has a switching circuit with the power supply,
The power from the power supply is supplied, and the apparatus main body 21 operates.
A P-channel MO is provided as a switching element between the positive electrode of the battery body 1a of the rechargeable battery 10 and the power supply line + Vcc.
S transistors 2 and 3 are connected in series. Also,
Negative electrode of battery body 1n and ground line GNDL
The detection resistor Rs of the current value detection circuit 4 is inserted in series between the two. The power supply line + Vcc is connected to the charging / discharging terminal 8a, and is connected to the apparatus main body 21 via this. The ground line GNDL is connected to the ground terminal 8.
b, through which the ground G of the device body 21 is connected.
Connected to ND. Here, MOS transistor 2
, A diode D1 which becomes forward with respect to the current in the charging direction and a diode D2 which becomes forward with respect to the current in the discharging direction (power supply direction) are connected in parallel to the MOS transistor 3, respectively. These diodes D
Here, body diodes 1 and D2 are formed in a parasitic manner between the drain and source of each transistor.

Each of the battery bodies 1a to 1n has a voltage detecting circuit 6a, 6b,.
6n are connected to the positive and negative electrodes and generate detection signals Dt, Ds, and DL, respectively. The gate control circuit 5 receives the detection signals Dt and Ds among these detection signals, and controls ON / OFF of the transistors 2 and 3. The gate control circuit 5 is a circuit operable in a range of, for example, about 2.4 V to 4.5 V, and receives power supply from a positive terminal of the battery body 1 a. Further, a charge permitting circuit 7 for permitting or prohibiting charging in response to each detection signal DL;
An impedance setting circuit 8 is provided which indicates whether or not external charging is possible by setting a state of impedance in response to a charging permission signal from the charging permission circuit 7. Each circuit including the gate control circuit 5 operates at a power supply voltage of 0.7 V × m (where m is the number of battery units connected in series) or more. In this case, m is set to 3 or more and 0.7
X3 = 2.4 V or more. Therefore, in the case of a so-called single battery with m = 1, 0.7
A gate control circuit, a detection circuit, and the like that operate at V or more will be employed.

The transistors 2 and 3 are switch transistors, and can flow a current in both directions in the ON state. These transistors are provided with bias resistors R1 and R2 between the source and the gate, respectively. Therefore, except for the case described later, in the steady state (when the total voltage of the battery body is m × 2.5 V to m × 4.2 V,
However, when m = 4, 10.0 V to 16.8 V)
In the initial state of charging start, the supply of the charging voltage higher than the total voltage of the battery body causes the bias resistor R2
As a result, the transistor 3 enters the N state. In the initial state of the discharge start in the steady state, the transistor 2 is turned on by the bias resistor R1.

The gate control circuit 5 includes a voltage detection circuit 6a,
A gate circuit 51 that receives the detection signal Dt from 6b to 6n and controls ON / OFF of the transistor 2, and a gate circuit that receives the detection signal Ds from the voltage detection circuits 6a and 6b to 6n and controls ON / OFF of the transistor 3. 55. Gate circuit 51 includes voltage detection circuits 6a, 6b to 6b.
AND gate 52 that receives a detection signal Dt from n, and a NOT OR gate (NOR gate) that receives the output of the AND gate 52 and the detection signal Dc of the current value detection circuit 4
53, an open-drain two-input OR gate 54 receiving the output of the NOT OR gate 53, and the other input of the OR gate 54 receives a charge enable signal (latch FF72Q bar output) from the charge enable circuit 7; The output is connected to the gate of transistor 2 and its output signal is applied to its gate.

The gate circuit 55 includes a voltage detection circuit 6
a, OR gate 5 receiving detection signal Ds from 6b to 6n
6, an AND gate 58 receiving an output of the OR gate 56 and a signal obtained by inverting a detection signal Dd of the current value detection circuit 4 by an inverter 57, and an open-drain two-input OR gate 5 receiving the output of the AND gate 58
9, and the other input of the OR gate 59 is provided with a charge enable signal (output of the latch FF72Q) from the charge enable circuit 7.
And its output is connected to the gate of transistor 3, and its output signal is applied to its gate.

The current detection circuit 4 charges or discharges by detecting the detection resistor Rs inserted in series downstream of the battery main bodies 1a to 1n and the terminal voltage of this resistor including its positive and negative directions. And the current value is detected, the detection voltage is a positive voltage, a detection signal Dc of a HIGH level (hereinafter “H”) is generated when the charging current is 25 mA or more, and the detection signal Dc is changed to a LOW level (hereinafter “L”) when the charging current is less than 25 mA. ). The detection signal Dd of "H" is generated when the detection voltage is a negative voltage and the discharge current is 25 mA or more, and the detection signal Dd is set to "L" when the discharge current is less than 25 mA.

The voltage detecting circuits 6a, 6b to 6n are voltage detecting circuits for detecting, on a battery unit basis, that the voltage on the positive electrode side is higher than a predetermined voltage with respect to the negative electrode side of the battery main bodies 1a to 1n. is there. Each battery body 1 (battery bodies 1a to 1b)
Since the full charge voltage (typically 1n) is usually about 4.2 V, the voltage detection circuit 6 (the voltage detection circuits 6a and 6a)
b to 6n), a signal of “H” is generated as the detection signal Dt when the voltage of the battery body 1 is, for example, 3.0 V or more. This detection signal is “L” when it is less than 3.0V. Further, when a predetermined value exceeding 4.2 V, for example, 4.3 V is reached, the detection signal Ds
To generate an "H" signal. This detection signal Ds is
It is "L" when the voltage of the battery body 1 is lower than a predetermined value exceeding 4.2V. Here, 4.2
The predetermined value exceeding V is a voltage at which the battery body 1 does not break or emit smoke.

Further, when the voltage of each battery body 1 becomes lower than 0.7 V, the detection signal DL is generated as "L" (negative logic significant) assuming that the overdischarge state has advanced and the battery has become unusable. This detection signal DL indicates that each battery body 1 has 0.7
It is "H" when the voltage is V or more. Note that a lithium battery normally has an overdischarge detection protection voltage of about 2.5 V, and can be charged and used if it is between about 0.7 V to 2.5 V. When the voltage falls below 7 V, the chemical composition generally changes, and the battery cannot be used. By the way, here, the voltage detection circuit 6
a, 6b to 6n are detection circuits of a hysteresis characteristic, and the detection signal Ds becomes “H” at 4.3 V or more,
The voltage drops from “H” to “L” at 4.0 V or less. In addition, the detection signal Dt also becomes “H” when the voltage is 3.0 V or more, and becomes “L” when the voltage falls from “H” and is 2.5 V or less.

The charge permission circuit 7 is a circuit for generating a signal for inhibiting charging when the battery body cannot be used, and for generating a charge permission signal when the battery body can be used. It comprises an AND gate 71, a data latch flip-flop (latch FF) 72, and a pull-down resistor R3. The AND gate 71 is connected to each of the voltage detection circuits 6a and 6b.
6n, and outputs a logical product to the reset terminal R bar (negative logic significant) of the latch FF72. Here, the AND gate 71 performs a negative OR operation, and resets the latch FF 72 to “0” when any one of the detection signals DL from each of the voltage detection circuits 6a, 6b to 6n becomes “L”. It has become. When the latch FF72 is reset, the Q output of the latch FF72 becomes “L” and the Q bar output (Q inversion output) becomes “H”. At this time, these signals are sent out as charge prohibition signals, and the "H" Q-bar output is input to the OR gates 54 and 59 to turn off the transistors 2 and 3, respectively. As a result, the charging / discharging terminal 8a is disconnected from the battery, and the charging battery 10 cannot be charged or discharged (power supply). That is, the battery body 1
(1a to 1n) become unusable. Note that, here, the Q output “H” and the Q bar output “L” of the latch FF 72 are charge permission signals (battery usable).

The data terminal D and the falling set terminal S bar of the latch FF72 are connected to the positive electrode side of the battery body 1a and receive the power supply voltage. Therefore, when a test signal is received at the clock input terminal CK, data is latched at the falling timing. This clock input terminal CK is connected to a ground line GNDL via a pull-down resistor R3. As a result, when the test signal P that changes to “L”, “H”, and “L” is received from the apparatus main body 21 via the test signal input terminal 9b to the clock input terminal CK, if the current state is not the reset state, the current “1” (or “H”) or “0” (or “L”) is set according to the level on the positive electrode side of the battery body 1a, and “H” of the Q output generated according to the set value is set. , "L" are output to the impedance setting circuit 8. When "1" is set, the charging is enabled, and when "0" is set, the Q-bar output becomes "H". As a result, the rechargeable battery 10 cannot be charged or discharged (supplied power).

The impedance setting circuit 8 is a circuit for setting the impedance detected from the outside according to the state of the battery, and includes an inverter 81, a two-input AND gate 82, and an N-channel MO provided as a switch circuit.
It comprises an S transistor 83 and a series resistance circuit 84. Inverter 81 includes voltage detection circuits 6a, 6b to 6n
And outputs the detection signal Ds from the OR gate 56 to one terminal of the AND gate 82 as a gate open signal. As a result, all of the detection signals Ds become “L”.
In other words, the gate of the AND gate 82 is opened when all of the battery bodies 1a to 1n are not in an overcharged state. The Q output of the latch FF 72 is input to the other input of the AND gate 82. At this time, if the Q output is “H” (charge enabled), “H” is added from the AND gate 82 to the gate of the transistor 83. Lever transistor 83 is turned ON. Note that the resistor R6 is a pull-down resistor inserted between the gate of the transistor 83 and the ground line GNDL.

The series resistor circuit 84 comprises a series circuit of resistors R4 and R5, and has a detection terminal 9a and a ground line GNDL.
Is connected between. The total resistance of the resistor R4 + the resistor R5 is 5.53 kΩ, and the resistance of the resistor R4 is selected to be 330Ω. The drain and source of the transistor 83 are connected between the connection point between the resistors R4 and R5 and the ground line GNDL. Therefore,
When the transistor 83 is turned on, the resistor R5 is short-circuited, and the resistance between the detection terminal 9a and the ground line GNDL becomes 330Ω, indicating that the battery can be charged (or can be used). The Q of the latch FF72
When the output is “L” (charge is impossible), the transistor 83
Is turned off, and the detection terminal 9a and the ground line GND are turned off.
The resistance value between L and 2,53 kΩ indicates that the battery cannot be charged (or cannot be used). Note that these resistance values are in accordance with the smart battery standard, and are selected so that the total value of the series resistance of the resistor of 425Ω or less and this resistor is in the range of 575Ω to 2850Ω. It is. Therefore, when the resistance value of the detection terminal 9a of 425Ω or less is 330Ω, charging is possible, and this is detected by the apparatus main body 21.

The detection terminal 9a and the ground line GNDL are connected to a battery state detection circuit 23 of the apparatus main body 21, whereby the impedance is detected.
It is detected whether charging is possible. The test signal P
Is supplied from the device main body 21 via the SM bus 13a in accordance with the above-described smart battery standard. At this time, the impedance between the inspection terminal 9a and the ground line GND changes to the SM bus 13a.
Is read by the MPU 24 of the apparatus main body 21 via the. As a result, the apparatus main body 21 knows whether the state is the charging permission state or the charging suspension state, and the MPU 24 performs processing according to the state.

In the following, the operation of the rechargeable battery 10 will be roughly divided into two cases. In the first case, each of the battery bodies 1 (battery bodies 1a to 1n) is initially charged to some extent in another battery manufacturing process, is not in an overdischarged state, and has a voltage of 0.7 V or more. And they shall be incorporated and used. Next, as a second case, a case in which the battery main body enters an abnormal state when the voltage drops below 0.7 V will be described. The operation in the first case will be described. In this case, all the gate circuits and transistors are in operation. However, it is assumed that each battery body 1 has not been initially charged to the extent of generating 3.0 V, and description will be made from charging from that point. In such a case, the voltage detection circuits 6a, 6b-6
In n, the detection signal Ds is “L”, the detection signal Dt is also “L”, and both the detection signals Dc and Dd of the current detection circuit 4 are “L”. However, the detection signal DL is “H”, and the latch FF 72 is not in the reset state.

Therefore, in the gate circuit 51, the input of the AND gate 52 becomes "L", the two inputs of the NOT OR gate 53 become "L", and the output thereof becomes "H". as a result,
The open-drain 2-input OR gate 54 is set to "H", and "H" is input to the gate of the transistor 2, which is turned off. On the other hand, in the initial state, the input and output of the OR gate 56 of the gate circuit 55 are "L" and the output of the inverter 57 is "H", but one input of the AND gate 58 is "L". The output becomes "L". Then, the open-drain two-input OR gate 59 is set to "L", "L" is input to the gate of the transistor 3, and this is turned on. When the rechargeable battery 10 is in such a state, the diode D1
Is inserted in the opposite direction to the discharge current, so that the transistor 2 is turned off. This prevents overdischarge and allows only charging by turning on the transistor 3.

At this time, when the test signal P changing from “L”, “H”, “L” is received from the apparatus main body 21 via the test signal input terminal 9b, the latch FF 72 of the charge permission circuit 7 The data of “1” (m = 4, the voltage of the power supply line of the battery body 1a, 0.7 × 4 = 2.4 V or more) is latched to generate “H” at the Q output, and “L” at the Q bar output. Occurs. At this time, the input and output of the OR gate 56 are
Since it is "L", the AND gate 82 of the impedance setting circuit 8 is open and the Q output "H"
3, the transistor 83 is turned on, and the resistance between the detection terminal 9a and the ground line GNDL becomes 33
It becomes 0Ω. As a result, the device main body 21 is detected by the battery state detection circuit 23 as chargeable, and charging is started from the device main body 21 via the power supply circuit 22.

Therefore, in the initial stage when the charging current is less than 25 mA, the battery body 1 is charged via the transistor 3 and the diode D1. Then, when the charging current becomes 25 mA or more, the detection signal Dc becomes "H", which is input to the NOT OR gate 53, and the output thereof becomes "L". As a result, the transistor 2
The state becomes the N state, and charging is continued. Thus, unnecessary power consumption is reduced without passing through the diode D1, and heat generation is suppressed. As the charging progresses, the terminal voltage of each of the battery bodies 1a to 1n is 3.0 V or more (m = 4, the voltage of the power supply line of the battery body 1a is 3.0 × 4 = 12.0 V or more).
, The detection signals D of the voltage detection circuits 6a, 6b to 6n
t are all "H", and at this time, the AND gate 5
2 becomes "H" and its output becomes "H". At this time, the output of the NOT OR gate 56 remains "L" and does not change. At this time, even if the charging current is less than 25 mA, the transistor 2 is maintained in the ON state. That is, the voltage of the power supply line of the battery body 1a is 3.0.
When × 4 = 12.0 V or more, the transistor 2 is turned on regardless of the charging current value, and the transistor 3 is also turned on at this time.

When the terminal voltage of any of the battery bodies 1a to 1n becomes 4.3V or more, the voltage detection circuits 6a, 6b to
One of the 6n detection signals Ds becomes “H”. At this time, at least one of the input sides of the OR gate 56 becomes "H", and the output thereof becomes "H". At this time, the output of inverter 57 is "H". Therefore, the two inputs of the AND gate 58 become "H", and the output also becomes "H". As a result, "H" is input to the gate of the transistor 3 via the OR gate 59, and this is turned off.
State and overcharge is prevented. When the charging of the rechargeable battery 10 is completed, the transistor 2 is in the ON state at this time, so that the discharging state in which the battery bodies 1a to 1n supply the power to the apparatus body 21 is maintained by the diode D2 being in the forward direction. Is done. At this time, the transistor 3 is turned off, and the transistor 3 is turned on only in the battery main body 1.
Side voltage (any one of the battery bodies 1a to 1n is acceptable)
Is 4.0 V or less and the detection signal Ds becomes “L” (according to the hysteresis characteristic described above).

When the AC power supply is removed, the power supply is switched by the power supply circuit 22 of the apparatus main body 21, and current is supplied to the apparatus main body 21 from the rechargeable battery 10 side. When the discharge is performed in this state, first, the discharge current is 25 mA.
Hereinafter, since the detection signal Dd is "L", a discharge current flows through the diode D2. This discharge current is 25m
When the voltage exceeds A, the detection signal Dd becomes “H” and the output of the inverter 57 becomes “L”. Then, one of the inputs of the AND gate 58 becomes "L", "L" is inputted to the gate of the transistor 3 through the OR gate 59, and this transistor 3 is turned on, and the discharge current is passed through the transistor 3 and the discharge current is reduced. Supplied to Thus, unnecessary power consumption is reduced without passing through the diode D2, and heat generation is suppressed. Discharging is performed in this state, and the voltage on the battery side gradually decreases. Note that when the voltage of any one of the battery bodies 1 becomes 4.0 V or less due to the discharge of the power supply, the detection signal Ds becomes “L”, and “L” is input to the gate of the transistor 3. This transistor is turned on. At this time, transistor 2
Is also ON.

The terminal voltage of any one of the battery bodies 1a to 1n is 3.0 V or less (2.5 V or less when 2.5 V or less with hysteresis characteristics is set to "L"). ), One of the detection signals Dt of the corresponding voltage detection circuits 6a, 6b to 6n becomes "L". At this point, one of the inputs of the AND gate 52 becomes "L" and its output also becomes "L". Then, since the detection signal Dc is "L", both inputs of the NOT OR gate 53 become "L", and the output thereof becomes "H".
Becomes As a result, "H" is input to the gate of the transistor 2 via the OR gate 54, and this is turned off. This prevents overdischarge. At this time, since the discharge current becomes “0”, the detection signal Dd also becomes “L”. Then, the output of the inverter 57 becomes “H”. At this time, the terminal voltage of any one of the battery bodies 1 a to 1 n is 2.5 V (3. if there is no hysteresis characteristic described above).
0V) or less, the voltage detection circuits 6a, 6b
Any or all of the 6n detection signals Dc are "L"
It has become. Then, two inputs of the AND gate 58 become "H" and "L", and the output thereof becomes "L". As a result, "L" is input to the gate of the transistor 3 via the OR gate 59, and this is turned on, and the rechargeable battery 10
Is maintained in a state in which the charging current is supplied from the apparatus main body 21 side.

As described above, at this time, when the test signal P is received from the apparatus main body 21 via the test signal input terminal 9b, the latch FF 72 of the charge enable circuit 7 latches the data of "1" and "H" is generated at the output. The terminal voltage of any one of the battery bodies 1a to 1n is 2.5V
This is because the voltage on the positive electrode side of the battery main body 1a is at the "H" level even when the voltage drops below (3.0 V in the absence of the hysteresis characteristic). Then, the AND gate 82 of the impedance setting circuit 8 is opened, and the Q output “H” is applied to the transistor 83, which is turned on, and the detection terminal 9a
And the ground line GNDL has a resistance value of 330Ω. As a result, the apparatus main body 21 is connected to the battery state detection circuit 2.
3, the charge can be detected. In the above case, the detection signal DL is “H”, and the latch FF 72 is not in the reset state.

Next, one of the battery bodies 1a to 1n
Alternatively, a charging operation in the case where all the voltages are less than 0.7 V will be described. In this case, in order to prevent over-discharge or by using the bias resistor R1, the transistor 2
Is in the OFF state and there is no discharging operation. First, all of the battery bodies 1a to 1n are 0.7V or less, and the voltage of 0.7V × m (the voltage on the positive electrode side of the battery body 1a) reaches the voltage at which the internal circuit of the rechargeable battery 10 operates. If not, at this time, the transistor 83 is turned off by the pull-down resistor 6, the resistance value between the detection terminal 9a and the ground line GNDL becomes 2.53 kΩ, indicating that the rechargeable battery 10 is unusable. At this time, since the transistors 2 and 3 are both pulled up by the resistors R1 and R2, they are in the OFF state. Therefore, the operation as the rechargeable battery 10 is set to be impossible. Even if the test signal P is received from the apparatus main body 21 via the test signal input terminal 9b, the latch F
Since the F72 does not operate, the above state is not affected.

At least one of the battery bodies 1a to 1n has a voltage of 0.7 V or less and a voltage of 0.7 V × m (voltage on the positive electrode side of the battery body 1a) is a voltage at which an internal circuit of the rechargeable battery 10 operates. At this time, one of the detection signals DL becomes "L", so that when the test signal P is received from the apparatus main body 21 via the test signal input terminal 9b, the latch FF72 is reset. . Therefore Q
The output becomes “L”, and the transistor 83 is set to OFF. The resistance value between the detection terminal 9a and the ground line GNDL becomes 2.53 kΩ, indicating a state in which it cannot be used. On the other hand, the Q-bar output of the latch FF72 becomes "H", "H" is input to the gates of the transistors 2 and 3 via the OR gates 54 and 59, and the transistors 2 and 3 are maintained in the OFF state. As a result, as described above, the rechargeable battery 10 enters the unusable state.

Even if one of the battery bodies 1a to 1n happens to have a voltage of 0.7 V or less and recovers to 0.7 V or more due to a temperature rise, the detection is performed as long as the test signal P is not input to the test signal input terminal 9b. The resistance between the terminal 9a and the ground line GNDL becomes 2.53 kΩ, indicating that the terminal 9a cannot be used. However, here, the test signal input terminal 9
When the test signal P is input to the latch FF 72
Holds “1”, and the Q output of the latch FF72 becomes “H”.
And the Q bar output becomes “L”, and the OR gate 5
“L” is input to the gates of the transistors 2 and 3 via the transistors 4 and 59, and the transistors 2 and 3 are maintained in the ON state. Also, the transistor 83 is turned on in response to the Q output “H”, and the detection terminal 9a and the ground line GN
The resistance between the DLs is 330Ω, indicating that charging is possible.

In the charging permission circuit 7 shown in FIG. 1, a pull-down resistor R3 is provided at the clock input terminal CK. This is because when the circuit operation power supply voltage is insufficient, or when the circuit is in a stopped state, a voltage is supplied through the charging / discharging terminal 8a for charging to increase the voltage of the power supply line to the operating state. Then, there is a risk of malfunction. That is, when the state where the clock input terminal CK is pulled up is set to the initial state, the latch FF72 is erroneously set.
Is reset. However, the state is changed from "L" input to "H" and "L" by the test signal P by pulling down by the pull-down resistor R3, so that a voltage is supplied through the charge / discharge terminal 8a for charging. Such a problem does not occur even if the voltage of the power supply line is increased to operate.

Next, a description will be given of the use state of the rechargeable battery 10 and the return to the use state when the rechargeable battery 10 enters the unusable state. As described above, after charging the rechargeable battery 10 by assembling the rechargeable battery 10 into the apparatus main body 21, the rechargeable battery 10
It is set in the range of up to 4.2 V, and maintains a state in which charging and discharging are possible. Even if the battery body 1 is not used at all after being assembled, the battery body 1 that is overdischarged by 0.7 V or less is considered to be hardly generated by overdischarge protection. Therefore, the resistance between the detection terminal 9a and the ground line GNDL is 33
It is maintained at 0Ω, charging and discharging are performed in this state, and the rechargeable battery 10 is used. Therefore, the re-use of the rechargeable battery 10 when it is not used may be performed in a special case such as during service. Therefore, a special case such as service will be described with reference to FIG. 2. As shown in the cross-sectional view of FIG. 2A, the input terminal 9 b is provided on the substrate 30, and the housing or package 31 including the rechargeable battery 10 is provided. A hole 32 is formed in the hole, and the hole is closed with a seal 33. Then, at the time of service or the like, the seal is peeled off as shown in FIG. 2B, and a test signal P is given by the battery 34, so that the battery is reset and the charged battery can be reused. If necessary, a certain battery body 1 having a voltage of 0.7 V or less is replaced, and then a test signal P is applied to return the battery to the original charge, to start charging and return to a normal state (see above). State).

As shown in FIG. 2C, an antenna 35, a receiving circuit 36, a tuning circuit 37, and a demodulation circuit 38 are provided in the rechargeable battery 10 to provide a modulation circuit 39a, an antenna 39b, and a power supply 39c. The test signal P may be generated by the test signal P generator 39 composed of Of course, the apparatus main body 21 as described above may be provided, and charging may be started and returned by the processing of the MPU.

As described above, in the embodiment, an example is described in which switch circuits having diodes in parallel are connected in series. However, in the present invention, one switch circuit is provided without providing a diode. Even when this is turned on / off, it can be applied. In short, according to the present invention, when the switch circuit is turned off when the voltage is equal to or lower than the operating voltage of the gate control circuit and the battery is set to the non-use state in which the rechargeable battery cannot be charged, the switch circuit receives an external signal and receives the signal. Is turned on so that charging can be performed. In the case where a switch circuit having diodes in parallel as in the embodiment is connected in series, a normal charge / discharge voltage range between the overdischarge protection voltage and the overcharge protection voltage is less than the overcharge protection voltage. M in parallel
The switches of the first and second switch circuits of the OS transistor are set to the ON state. However, in the present invention, at least at the time of charging, the switch (MOS transistor 3) of the second switch circuit is set to the ON state. Then, when the voltage on the positive electrode side of the battery body exceeds a predetermined voltage for preventing overdischarge and the battery is discharged, the switch (MOS transistor 2) of the first switch circuit only needs to be set to the ON state. It is not always necessary to set the switches of each switch circuit to the ON state in accordance with the signal of the control circuit. For example, R1 and R2 in FIG.
It is also possible to insert a bias resistor such as the above, and various circuits can be used. Further, in the embodiments, the description is focused on a lithium battery. However, the present invention can be similarly applied to an electric double layer capacitor usable as a battery, that is, a so-called supercapacitor. The present invention can also be applied to a secondary battery for charging. Therefore, the concept of the battery body here includes the capacitor.

In the embodiment, a diode is connected in parallel to the switch circuit of the MOS transistor. However, the diode is not limited to a body diode, and may be a discrete diode. Another diode formed on the substrate may be used. Further, in the embodiment, the example of the MOS transistor is described as the switch blocking inserted between the charging / discharging power supply line and the battery main body, but it is needless to say that a bipolar transistor or an analog switch may be used. Furthermore, in the embodiments, a rechargeable battery in which a circuit including a battery main body and a charge controller is integrated as a rechargeable battery is described. However, the present invention relates to a so-called rechargeable battery pack in which a recharging circuit and a battery are individually separated in advance. It is needless to say that the present invention can be applied as it is to a rechargeable battery pack formed by integrating the above.

[0041]

As described above, according to the present invention, the control circuit is not a program operation processor, but a control circuit.
A switch circuit which is configured by a gate control circuit and is turned off when the voltage is equal to or lower than the operating voltage of the gate control circuit receives a signal from outside the rechargeable battery and turns the switch circuit on.
By providing the charge permission circuit for setting the state to the N state, it is not necessary to perform a power-on reset process, and it is possible to prevent overcharge and overdischarge, thereby preventing unauthorized charging. As a result, the portion for storing the usage environment history information collected by the various sensors can be separated from the charge / discharge control circuit, and the environment history information does not need to be erased. In particular, in another configuration of the present invention, the first and second switch circuits each including a parallel circuit of a diode and a switch and having diodes arranged in opposite directions are connected between the charge / discharge power supply line and the battery body. And a second diode having a diode that is in the opposite direction to charging when in a charged state.
The switch of this switch circuit is turned on as an initial state, and is charged via a forward diode parallel to the first switch circuit. Then, the switch of the first switch circuit is turned on when the charging current value exceeds a certain value.
Charging is performed by reducing the voltage drop without passing through a diode as a state. As a result, heat radiation due to the charging current can be reduced, and unnecessary power consumption can be suppressed.

[Brief description of the drawings]

FIG. 1 is a circuit diagram mainly showing a lithium rechargeable battery built in an electronic device of an embodiment to which a rechargeable battery of the present invention is applied.

FIGS. 2A and 2B are explanatory views of a structure for returning from an unused state. FIG. 2A is a cross-sectional view of a housing containing a rechargeable battery, and FIG. (C) is an explanatory diagram of a return process by radio waves.

[Explanation of symbols]

1, 1a, 1b, 1n: Lithium battery main body (battery main body), 2, 3: P-channel MOS transistor, 4: current value detection circuit, 5: gate control circuit, 6, 6a, 6b, 6n: voltage detection circuit , 7: charge permission circuit, 8: impedance setting circuit, 10: rechargeable battery, 20: electronic device, 21: device body, 22: power supply circuit, 23: battery state detection circuit, 24: MPU, 51, 55: gate circuit , 52, 58, 82 ... AND gate, 53 ... NOT OR gate (NOR gate), 54, 56,
Reference numeral 59: OR gate, 57, 81: Inverter, 71: AND gate, 72: Data latch flip-flop (latch FF) 83: N-channel MOS transistor, 84: Series resistance circuit, D1, D2: Diode, R1 to R4: Resistance.

Continuing from the front page (72) Inventor Koichi Horisaki 1-1-88 Ushitora, Ibaraki-shi, Osaka Within Hitachi Maxell Co., Ltd. (72) Masato Suzuki 1-188 Ushitora, Ibaraki-shi, Osaka Hitachi Maxell shares Inside the company (72) Inventor Mitsunori Tsuchiya 5-2-1, Kamisumihonmachi, Kodaira-shi, Tokyo Inside Hitachi Super-LSI Systems Co., Ltd. -22-1 F-term in Hitachi ULSI Systems (reference) 5G003 AA01 BA01 DA07 DA13 FA04 GA01 GC03 GC05 5H030 AA03 AS18 AS20 BB01 BB18 BB27 DD01 FF43 FF44

Claims (6)

[Claims] 1. A battery circuit, a charge / discharge power supply line connected to a charging circuit or a load for supplying power, and a switch circuit connected in series between the charge / discharge power supply line and the battery body. Detecting that the voltage of the positive terminal of the battery body is equal to or higher than a predetermined voltage exceeding the voltage of the full charge and generating a first detection signal, and causing the voltage of the positive terminal of the battery body to overdischarge. A voltage detection circuit that detects that the voltage is equal to or lower than a predetermined voltage to prevent the voltage, and generates a second detection signal; A gate control circuit that sets the switch circuit to an ON state at one time, and turns off the switch circuit when the first detection signal is received and the second detection signal; Outside And a charge permission circuit that turns on the switch circuit in response to a signal from the gate control circuit, wherein the switch circuit is turned off when the voltage on the positive electrode side is lower than or equal to the operating voltage of the gate control circuit. A rechargeable battery, wherein a voltage detection circuit and the gate control circuit operate by receiving power from the battery body. 2. A battery main body, a charge / discharge power supply line connected to a charging circuit or a load for supplying electric power, and the charge / discharge power supply line connected in series between the charge / discharge power supply line and the battery main body. A first switch circuit including a diode in a forward direction with respect to a charging current flowing from the power supply line to the battery body and a switch provided in parallel with the diode; and a charge / discharge power supply line and the battery body. A second switch circuit including a diode connected in series between the battery and a forward direction with respect to a discharge current flowing from the battery main body to the charge / discharge power supply line, and a switch provided in parallel with the diode; Detecting that the charging current value for the main body is equal to or greater than a predetermined value, generating a first detection signal, and determining that the discharging current value from the battery main body is equal to or greater than a predetermined value. A current detection circuit for detecting and generating a second detection signal; and a third circuit for detecting that the voltage of the positive terminal of the battery body is equal to or higher than a predetermined voltage exceeding the full charge voltage with respect to the negative electrode. A voltage detection circuit that generates a detection signal, detects that the voltage at the positive terminal of the battery body is equal to or lower than a predetermined voltage that prevents overdischarge with respect to the negative electrode, and generates a fourth detection signal; Receiving the first detection signal, turning on the switch of the first switch circuit, receiving the second detection signal, turning on the switch of the second switch circuit, receiving the third detection signal A gate control circuit that turns off the switch of the second switch circuit and that turns off the switch of the first switch circuit in response to the fourth detection signal; Receiving A charge enable circuit for turning on a switch of the first switch circuit and a switch of the second switch circuit, wherein when the voltage on the positive electrode side is lower than or equal to the operating voltage of the gate control circuit, The switch of the switch circuit and the switch of the second switch circuit are turned off, and at least at the time of charging, the switch of the second switch circuit is turned on, and the voltage on the positive electrode side of the battery body is The switch of the first switch circuit is set to an ON state at the time of discharging when the voltage exceeds a predetermined voltage for preventing overdischarging, and the current detection circuit, the voltage detection circuit, and the gate control circuit are connected to the battery. The rechargeable battery described above, which operates by receiving power from a main body. 3. The gate control circuit receives the first detection signal, turns on the switch of the first switch circuit while the signal is being generated, and receives the second detection signal. While the signal is being generated, the switch of the second switch circuit is turned on, and the voltage on the positive electrode side of the battery main body is a predetermined state for preventing the overdischarge as an initial state before the charging. 2. The rechargeable battery according to claim 1, wherein the switch of the first switch circuit is set to an OFF state when the voltage is equal to or lower than the voltage of the first switch circuit. 4. The switch comprises a transistor,
The gate control circuit receives the first detection signal and receives the first detection signal as a circuit for turning on the switch of the first switch circuit while the signal is being generated. A first gate circuit to be turned on, and receiving the second detection signal and turning on the switch of the second switch circuit while the signal is being generated.
A second gate circuit that receives the second detection signal and turns on the transistor.
When the voltage on the positive electrode side of the battery body is a predetermined voltage for preventing the over-discharge or within a range from a predetermined voltage exceeding the predetermined voltage to a predetermined voltage equal to or lower than the full voltage, the first voltage is applied.
The rechargeable battery according to claim 2, wherein the switch of the second switch circuit is set to an ON state. 5. A battery main body, a charge / discharge power supply line connected to a charging circuit or a load for supplying power, and a switch circuit connected in series between the charge / discharge power supply line and the battery main body. Detecting that the voltage of the positive terminal of the battery body is equal to or higher than a predetermined voltage exceeding the voltage of the full charge and generating a first detection signal, and causing the voltage of the positive terminal of the battery body to overdischarge. A voltage detection circuit that detects that the voltage is equal to or lower than a predetermined voltage to prevent the voltage, and generates a second detection signal; A gate control circuit that sets the switch circuit to an ON state at one time, and turns the switch circuit to an OFF state when the first detection signal and the second detection signal are received; Have a charge enabling circuitry to the ON state the switch circuit receives an external signal,
The switch circuit is turned off when the voltage on the positive electrode side is equal to or lower than the operating voltage of the gate control circuit, and the voltage detection circuit and the gate control circuit operate by receiving power from the battery body. Characteristic rechargeable battery pack. 6. A battery main body, a charging / discharging power supply line connected to a charging circuit or connected to a load for supplying electric power, and the charging / discharging power supply line connected in series between the charging / discharging power supply line and the battery main body. A first switch circuit including a diode in a forward direction with respect to a charging current flowing from the power supply line to the battery body and a switch provided in parallel with the diode; and a charge / discharge power supply line and the battery body. A second switch circuit including a diode connected in series between the battery and a forward direction with respect to a discharge current flowing from the battery main body to the charge / discharge power supply line, and a switch provided in parallel with the diode; Detecting that the charging current value for the main body is equal to or greater than a predetermined value, generating a first detection signal, and determining that the discharging current value from the battery main body is equal to or greater than a predetermined value. A current detection circuit for detecting and generating a second detection signal; and a third circuit for detecting that the voltage of the positive terminal of the battery body is equal to or higher than a predetermined voltage exceeding the full charge voltage with respect to the negative electrode. A voltage detection circuit that generates a detection signal, detects that the voltage at the positive terminal of the battery body is equal to or lower than a predetermined voltage that prevents overdischarge with respect to the negative electrode, and generates a fourth detection signal; Receiving the first detection signal, turning on the switch of the first switch circuit, receiving the second detection signal, turning on the switch of the second switch circuit, receiving the third detection signal A gate control circuit that turns off the switch of the second switch circuit, and that turns off the switch of the first switch circuit in response to the fourth detection signal; Signal A charge permission circuit for turning on a switch of the first switch circuit and a switch of the second switch circuit, and when the voltage on the positive electrode side is lower than or equal to the operating voltage of the gate control circuit, The switch of the first switch circuit and the switch of the second switch circuit are turned off, and at least at the time of charging, the switch of the second switch circuit is turned on, and the voltage of the battery body on the positive electrode side is turned on. When the voltage exceeds a predetermined voltage for preventing the overdischarge and the discharge is performed, a switch of the first switch circuit is set to an ON state, and the current detection circuit, the voltage detection circuit, and the gate control circuit are connected to each other. The rechargeable battery pack, which operates by receiving power from the battery body.