JP2004247322A - Battery pack and battery protection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for protecting a battery itself from a short circuit even if the positive electrode and the negative electrode on the outside are short-circuited by contacting. <P>SOLUTION: A switch circuit 14 provided on the positive electrode side of the battery 11 is operated in response to the potential of the positive electrode terminal 12. That is, the switch circuit 14 is normally made "on" in the state of being removed, and when the positive electrode 12 and the negative electrode 13 are short-circuited by some contacting or so of the conductor on the outside, the potential of the positive electrode 12 drops and the switch circuit 14 is made "off". <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to battery protection in a device that operates using a battery such as a portable electronic device, and in particular, a battery pack in which a predetermined number of batteries are housed in a container together with related circuits and integrated, and such a battery. The present invention relates to a battery protection device provided in an apparatus used by loading a pack.

  In recent years, in information processing electronic devices such as so-called OA devices, the demand for portable electronic devices, that is, portable electronic devices has been increasing. In most cases, such portable electronic devices use a commercial power supply. It can be driven by batteries even in places where it is not possible.

  In such an electronic device, a rechargeable secondary battery, such as a nickel-cadmium battery or a nickel-hydrogen battery, is used as a battery, rather than a general primary battery such as a dry battery such as a manganese battery and an alkaline battery. In many cases, a plurality of power supplies are used in combination to obtain required power. Therefore, in general, a predetermined number of batteries are housed in a container together with related circuits and integrated to form a battery pack, and the battery pack is used by being loaded into an electronic device. The battery itself is a kind of consumable because it deteriorates, and is configured to be detachable from an electronic device.

  A battery pack is provided with a positive electrode terminal, a negative electrode terminal, and the like for connection to a device, and such a positive electrode terminal and a negative electrode terminal are often protruded from an external side surface or the like. However, since the battery pack is detachable, it is often the case that the battery pack is carried around, for example, as a spare, without being loaded into an electronic device, like a normal battery. In such a case, if the positive electrode terminal and the negative electrode terminal protrude from the outer surface, a short circuit may occur between the two terminals due to contact with a conductor such as a metal outside. A short circuit between the positive electrode terminal and the negative electrode terminal of the battery causes deterioration of the battery, heat generation, liquid leakage, and the like.

  Therefore, in such a battery pack, it is necessary to prevent a short circuit between the positive electrode terminal and the negative electrode terminal. As a short-circuit protection technique for a battery pack or the like, conventionally, a fuse or a self-recoverable switch element has been used. That is, in the case of the fuse, the fuse is inserted in series with the discharge path of the battery current, and when the fuse is short-circuited, the fuse is blown by the current flowing through the discharge path or the heat generated thereby, thereby causing the discharge. Disconnect the path. In the case of the switch element, a self-recoverable switch element is inserted in series with the discharge path, and when a short circuit occurs, the switch element is turned off by a current or the like flowing through the discharge path, thereby setting the discharge path. Disconnect. In this way, in the event of a short circuit, the discharge path is immediately disconnected to prevent the battery from generating heat and liquid leakage due to the short circuit.

  In some cases, the terminal portions such as the positive electrode terminal and the negative electrode terminal are formed in a special shape so that the terminal portion is not easily contacted with the outside except when the terminal portion is attached to a dedicated connector. For example, a plurality of concave portions corresponding to the number of terminals are formed on the outer surface of the battery pack, and a contact made of a conductive metal or the like of the terminal portion is provided on the bottom surface of the concave portion, and an insulator around the contact is provided. For example, by increasing the height, a barrier portion made of an insulator is formed between the contact of the positive terminal and the contact of the negative terminal to deal with the danger of a short circuit.

In the case of the above-described short-circuit protection by the shape near the terminal portion, the contact of the electrode terminal simply does not easily contact the external metal or the like, and there is a sufficient risk of contact. Therefore, if the contact is made, it goes without saying that a short circuit between the positive electrode terminal and the negative electrode terminal causes a problem such as sparks or heat generation.

  Even if excessive heat generation or the like can be prevented beforehand by protection using a fuse, there is a problem that it takes time and effort to replace the fuse to recover the blown fuse.

  When a switch element that is capable of self-recovery is used, it takes a time in seconds from the occurrence of a short circuit until the switch element is turned off, which causes deterioration of the battery.

  On the other hand, it is conceivable that a switch circuit is inserted on the negative electrode side of the battery, and a short-circuit protection circuit is configured using such a switch circuit. FIG. 11 shows an example of a short-circuit protection circuit including such a battery pack and its peripheral circuits.

In this case, on the device side, for example, 16 V DC power is supplied from the AC adapter to an external power terminal DC-IN to which an external DC power converted from a commercial AC power to DC by an AC adapter is input, It is assumed that the rated voltage of the battery BT is 3V. When the switch circuit SW is turned on, the potential of the terminal T becomes 3 V or less because the voltage of the battery BT is divided by the resistor R1 and the thermistor TM. That is, the withstand voltage of the device connected to the terminal T on the device side of about 10 V is sufficient. When the switch circuit SW is off, the positive terminal P is connected to the power terminal DC-IN through the resistor R1, so that the potential is 16V, and the positive terminal potential of the battery BT is 16V. Since the battery voltage is 3 V, the voltage on the negative electrode side of the battery BT is 16-3, that is, 13 V. In this state, the voltage Vt between the terminal T and the negative electrode terminal N is 13 to 16 V.

In this case, the withstand voltage of the device-side circuit connected to the terminal T is insufficient at 10 V, and the circuit may not be established depending on the circuit configuration. The DC power of, for example, 16 V supplied from the AC adapter to the external power terminal DC-IN is also used for charging the battery BT.

  The switch circuit SW is configured using, for example, an FET (field effect transistor). A gate terminal (not shown) for turning on / off the FET is drawn out. The device is turned on by short-circuiting it with the potential of the positive terminal P on the device side, so that the output of the battery can be taken out. become able to.

  Secondary batteries such as nickel-cadmium batteries and nickel-metal hydride batteries have heat during charging. Therefore, a thermistor TM is provided to protect the battery from overheating by detecting the battery temperature and stopping charging. ing.

After the completion of charging, the battery BT is discharged by self-discharge. Therefore, as a so-called trickle charge to compensate for the self-discharge, a small amount of charge is constantly performed from the external power supply terminal DC-IN via the resistor R2.

  In this case, when all the terminals are short-circuited externally, the gate control terminal of the switch circuit SW is short-circuited to the negative terminal N and becomes the ground potential, so that the switch circuit SW is turned off. -There is no short circuit between the negative electrodes.

  In a similar battery pack, if a switch circuit is provided on the positive electrode side of the battery, the gate terminal for turning on / off the FET of the switch circuit is turned on by short-circuiting to the negative electrode potential on the device side. .

  In that case, if all terminals are short-circuited externally, the gate control terminal is short-circuited to the negative electrode terminal and becomes a negative electrode potential, so that the switch circuit is turned on, and the external battery is short-circuited between the positive electrode and the negative electrode. May be done.

  The present invention has been made in order to solve such a problem, and provides a battery pack which can protect a battery itself from a short circuit even if the positive electrode terminal and the negative electrode terminal on the outer surface are short-circuited by contact. It is intended to be.

  Further, the present invention provides a battery protection device which enables a device to control switches inside the battery pack without adversely affecting other circuits even when a battery pack having a built-in protection switch is used. It is aimed at.

  A first battery pack according to the present invention includes a battery having a positive electrode and a negative electrode, a positive terminal for device connection, a negative terminal for device connection, connected to the negative electrode of the battery, and a positive terminal for the positive terminal. To disconnect the positive electrode terminal and the positive electrode of the battery when the potential is reduced so as to be substantially equal to the negative electrode of the battery, and to conduct between the positive electrode terminal and the positive electrode of the battery at other times. Switch means.

  The switch means includes a first switch for turning on and off between the positive electrode terminal and the positive electrode of the battery, and a positive electrode of the battery if the positive terminal and the negative terminal are not externally short-circuited. And the positive electrode terminal is turned on by decreasing the potential of the positive terminal to a potential substantially equal to the negative electrode of the battery, thereby applying a control voltage to the first switch to turn off the first switch. And a second switch.

  A second battery pack according to the present invention includes a battery having a positive electrode and a negative electrode, a positive terminal for device connection, a negative terminal for device connection, and a negative terminal connected to the negative electrode of the battery, and a device for device connection. The control terminal, when the potential of the control terminal is reduced so as to be substantially equal to the negative electrode of the battery, conducts between the positive terminal and the positive electrode of the battery. Switch means for disconnecting from the positive electrode.

  The switch means includes a first switch for turning on and off between the positive electrode terminal and the positive electrode of the battery, and the control terminal being enabled in an on state, so that the control terminal has a potential substantially equal to the negative electrode of the battery. A second switch for enabling on control of the first switch by lowering, forcibly turning off the first switch by disconnecting the control terminal in an off state, and a positive terminal; If the control terminal and the negative electrode terminal are not short-circuited externally, they are turned on by the potential of the positive electrode of the battery, and the positive terminal drops to a potential substantially equal to the negative electrode of the battery. A third switch which is controlled to be turned off by a potential of a negative electrode of the battery and controls the second switch to be turned off by a potential of a positive electrode of the battery It may be provided with a switch.

  A third battery pack according to the present invention includes a battery having a positive electrode and a negative electrode, a positive terminal for device connection, a negative terminal for device connection, and a negative terminal connected to the negative electrode of the battery; A control terminal, a voltage sense terminal for device connection, to which a potential is supplied from a positive electrode of the battery, and a control terminal when the voltage sense terminal and the control terminal are short-circuited externally. A switch means for conducting the electrical connection between the positive electrode terminal and the positive electrode of the battery according to the applied potential of the positive electrode of the battery and disconnecting the positive electrode terminal and the positive electrode of the battery at other times. are doing.

The switch means is controlled by a first switch for turning on and off between the positive electrode terminal and the positive electrode of the battery, and a potential of the control terminal, and the control terminal is connected to a potential of the positive electrode of the battery. A second switch that is controlled to turn on the first switch when it is turned on, and is turned off by the potential of the negative electrode of the battery otherwise to turn off the first switch. You may.

  A first battery protection device according to the present invention is a battery having a positive electrode and a negative electrode, a positive electrode terminal, a negative terminal connected to the negative electrode of the battery, a control terminal, and a potential of the control terminal, the potential of the control terminal First switch means for conducting between the positive electrode terminal and the positive electrode of the battery when the voltage drops substantially equal to the negative electrode, and disconnecting the positive terminal and the positive electrode of the battery at other times; A load unit that operates with power supplied from the positive terminal and the negative terminal of the battery pack, and a control terminal of the battery pack that is provided in association with the load unit and that is controlled by a control signal supplied from the load unit. And a second switch means for short-circuiting and disconnecting between the power supply and the negative electrode terminal.

  A second battery protection device according to the present invention includes a battery having a positive electrode and a negative electrode, a positive terminal, a negative terminal connected to the negative electrode of the battery, a control terminal, and a potential supplied from the positive electrode of the battery. A voltage sense terminal, between the positive electrode terminal and the positive electrode of the battery, due to the potential of the positive electrode of the battery given to the control terminal when the voltage sense terminal and the control terminal are short-circuited externally A load that operates with power supplied from the positive terminal and the negative terminal of the battery pack having first switch means for disconnecting the positive terminal and the positive electrode of the battery at other times. Means and a short circuit between the control terminal and the sense terminal of the battery pack by a control signal provided from the load means and provided in connection with the load means. And and a second switching means for performing disconnection.

  In the first battery pack of the present invention, the switch disconnects the positive electrode terminal from the positive electrode of the battery when the potential of the positive electrode terminal is reduced so as to be substantially equal to the negative electrode of the battery. By conducting between the positive electrode terminal and the positive electrode of the battery, even if the positive electrode terminal and the negative electrode terminal on the outer surface are short-circuited due to contact, the battery itself can be protected from the short circuit.

  Further, the second battery pack of the present invention has a control terminal, and when a potential of the control terminal is reduced by a switch so as to be substantially equal to a negative electrode of the battery, the second battery pack is connected between the positive electrode terminal and the positive electrode of the battery. Between the positive electrode terminal and the positive electrode of the battery at other times.

  The third battery pack of the present invention has a voltage sense terminal and a control terminal, and is provided to the control terminal when the voltage sense terminal and the control terminal are short-circuited externally by a switch. The electric potential of the positive electrode of the battery allows conduction between the positive terminal and the positive electrode of the battery, and otherwise disconnects the positive terminal from the positive electrode of the battery.

  The first battery protection device of the present invention, the control terminal, when the potential of the control terminal is reduced so as to be substantially equal to the negative electrode of the battery, conducts between the positive electrode terminal and the positive electrode of the battery, Sometimes a load is operated with power supplied from the positive terminal and the negative terminal of the battery pack having the first switch for disconnecting the positive terminal and the positive electrode of the battery, A second switch provided for short-circuiting and disconnecting the control terminal and the negative terminal of the battery pack in response to a control signal supplied from the load side, thereby adversely affecting other circuits; Instead, the switches inside the battery pack can be controlled from the device side.

The second battery protection device according to the present invention is configured such that when the voltage sense terminal and the control terminal are short-circuited externally, the potential of the positive electrode of the battery applied to the control terminal causes the positive electrode terminal and the battery A load is supplied by power supplied from the positive terminal and the negative terminal of the battery pack having a first switch for conducting between the positive terminal and disconnecting the positive terminal from the positive terminal of the battery at other times. And, by a second switch provided in connection with the load, performing a short circuit / isolation between the control terminal and the sense terminal of the battery pack in response to a control signal supplied from the load side. Can be.

  According to the present invention, when the potential of the positive electrode terminal is reduced so as to be substantially equal to the negative electrode of the battery, for example, the positive electrode terminal and the positive electrode of the battery are separated by a switch, and the outer positive electrode terminal and the negative electrode terminal are separated. Can provide a battery pack that can protect the battery itself from a short circuit even if the battery pack is short-circuited by contact.

  Further, according to the present invention, when the potential of the control terminal is reduced so as to be substantially equal to the negative electrode of the battery, conduction between the positive electrode terminal and the positive electrode of the battery is performed; A load is operated by power supplied from the positive terminal and the negative terminal of the battery pack having a first switch for disconnecting the positive electrode from the positive electrode, and a second switch provided in connection with the load operates the load on the load side. The switch inside the battery pack can be switched from the device side without adversely affecting other circuits, for example, by short-circuiting or disconnecting the control terminal and the negative terminal of the battery pack in response to the control signal supplied from the device. Can be provided.

  Hereinafter, embodiments of a battery pack and a battery protection device according to the present invention will be described with reference to the drawings.

[Embodiment 1] FIG. 1 shows a basic configuration of a battery pack according to a first embodiment of the present invention.

  The battery pack of FIG. 1 includes a battery 11, a positive terminal 12, a negative terminal 13, and a switch circuit 14. The battery 11 includes a predetermined number of batteries, for example, a rechargeable secondary battery such as a nickel-metal hydride battery, and is connected between a positive electrode and a negative electrode to obtain a required voltage.

  The positive terminal 12 and the negative terminal 13 are terminals for connecting the output of the battery 11 to the outside of the battery pack, that is, to a device serving as a load. The switch circuit 14 is interposed between the positive electrode of the battery 11 and the positive electrode terminal 12, and is turned on / off in response to the potential of the positive electrode terminal 12, and operates between the positive electrode and the positive electrode terminal 12 of the battery 11. Connection / disconnection. The switch circuit 14 is turned off when the potential of the positive terminal 12 drops to a potential substantially equal to the potential of the negative electrode of the battery 11, and turned on otherwise.

  The battery pack of FIG. 1 is configured to be detachable from a device. In this battery pack, the switch circuit 14 provided on the positive electrode side of the battery 11 operates in response to the potential of the positive electrode terminal 12. That is, the switch circuit 14 is normally turned on in the detached state, and when the positive electrode terminal 12 and the negative electrode terminal 13 are short-circuited due to, for example, the contact of any conductor to the outside. In this case, the potential of the positive electrode terminal 12 decreases and the switch circuit 14 turns off. Therefore, the battery 11 is protected from a short circuit between the positive electrode and the negative electrode.

[Embodiment 2] FIG. 2 shows a configuration of a battery pack according to a second embodiment of the present invention. FIG. 2 shows an example of a specific configuration based on the principle of the first embodiment of the present invention shown in FIG.

  The battery pack in FIG. 2 includes a positive terminal 12, a negative terminal 13, a battery BT, a first transistor TR11, a second transistor TR12, a first resistor R11, and a second resistor R12.

  The positive terminal 12 and the negative terminal 13 are exactly the same as in FIG. The battery BT is, for example, a combination of a plurality of batteries, and is substantially the same as the battery 11 of FIG.

  The transistors TR11 and TR12 are switch elements, and in this case, are configured by FETs (field-effect transistors) whose on-off is controlled between the source and the drain by the gate potential. The transistor TR11 has a source connected to the positive electrode of the battery BT, a drain connected to the positive electrode terminal 12, and a gate connected to one end of the resistor R12. The other end of the resistor R12 is connected to the negative electrode terminal 13, that is, the negative electrode of the battery BT. The transistor TR12 has a source connected to the source of the transistor TR11, a drain connected to the gate of the transistor TR11, and a gate connected to the positive electrode of the battery BT, that is, the source of the transistor TR11 via the resistor R11.

  The diode shown by the broken line in FIG. 2 is a parasitic diode of the FET. The transistors TR11 and TR12 and the resistors R11 and R12 form a switch circuit corresponding to the switch circuit 14 in FIG.

  In the battery pack of FIG. 2, normally, the gate of the transistor TR12 is connected to the positive electrode of the battery BT via the resistor R11, so that the source and the gate of the transistor TR12 have the same potential, and the transistor TR12 is off. . Since the gate of the transistor TR11 is connected to the negative electrode of the battery BT via the resistor R2, the voltage of the transistor TR11 is 0 V (ground potential) lower than the potential of the source. The power of the battery BT can be output.

  When a short circuit occurs between the positive terminal 12 and the negative terminal 13 due to contact with a conductor or the like, the gate of the transistor TR12 has a potential corresponding to the negative terminal 13, that is, 0 V, and the transistor TR12 is turned on. When the transistor TR12 is turned on, the source and the gate of the transistor TR11 have the same potential, and the transistor TR11 is turned off.

  When this battery pack is used, a load is applied between the positive electrode terminal 12 and the negative electrode terminal 13, so that a resistance is inserted, and the transistor TR11 is turned off unless the potential of the positive electrode terminal 12 drops extremely extremely. No. That is, the transistor TR11 is switched by checking whether the potential of the positive electrode terminal 12 is extremely low.

[Embodiment 3] FIG. 3 shows a basic configuration of a battery pack according to a third embodiment of the present invention.

The battery pack 1 of FIG. 3 includes a control terminal 21 and a switch circuit 22 in addition to the battery 11, the positive terminal 12, and the negative terminal 13 similar to those of FIG. FIG. 3 also shows a positive terminal 23, a negative terminal 24, a control terminal 25, and the like on the device 2 side to which the battery pack 1 is mounted.

As in the case of FIG. 1, the battery 11 includes a predetermined number of batteries, for example, a rechargeable secondary battery such as a nickel-metal hydride battery, and is connected between the positive electrode and the negative electrode so as to obtain a required voltage. ing. The positive terminal 12 and the negative terminal 13 are terminals for connecting the output of the battery 11 to the outside of the battery pack, that is, to a device serving as a load.

  The control terminal 21 is a terminal for supplying a control signal from the device 2 to the switch circuit 22. The switch circuit 22 is interposed between the positive electrode of the battery 11 and the positive electrode terminal 12, and is turned on / off in response to the potentials of the positive electrode terminal 12 and the control terminal 21, so that the positive electrode and the positive electrode terminal of the battery 11 are turned off. 12 is connected / disconnected. The switch circuit 22 is configured such that the control terminal 21 and the negative terminal 13 are short-circuited via the control terminal 25 and the negative terminal 24 on the device 2 side, so that the potential of the control terminal 21 becomes substantially equal to the potential of the negative electrode of the battery 11. It turns on when it drops, and turns off otherwise. Further, similarly to the switch circuit 14 of FIG. 1, even when the control terminal 21 and the negative terminal 13 are short-circuited, the potential of the positive terminal 12 is substantially equal to the potential of the negative electrode of the battery 11. It turns off when it drops to

  The positive terminal 23, the negative terminal 24, and the control terminal 25 of the device 2 are connected to the positive terminal 12, the negative terminal 13, and the control terminal 21 of the battery pack 1 when the battery pack 1 is mounted on the device 2, respectively. The control terminal 25 and the negative electrode terminal 24 of the device 2 are short-circuited on the device 2 side.

  The battery pack 1 of FIG. 3 is configured to be detachable from the device, and a switch circuit 22 provided on the positive electrode side of the battery 11 operates in response to the potential of the control terminal 21. In the battery pack 1 shown in FIG. 3, the switch circuit 22 is turned on when the control signal of the control terminal 21 is substantially at the negative potential, and the switch circuit 22 is turned off at other times. It is turned off when the terminal 12 has almost reached the negative potential.

  That is, when the battery pack 1 is removed from the device 2, the switch circuit 22 is normally off, and when the battery pack 1 is mounted on the device 2, the switch circuit 22 is connected between the control terminal 21 and the negative terminal 13. Is turned on by short-circuiting, and a voltage is supplied from the positive terminal 12 to the device 2 via the positive terminal 23.

  When the control terminal 21 is not connected to the negative potential, the switch circuit 22 is off, so that even when the positive terminal 12 and the negative terminal 13 are short-circuited, the battery 11 does not short-circuit. When the control terminal 21 is connected to the negative potential and the switch circuit 22 is turned on, the potential of the positive terminal 12 decreases when the positive terminal 12 and the negative terminal 13 are short-circuited. Turns off. Therefore, the battery 11 is protected from a short circuit between the positive electrode and the negative electrode.

[Embodiment 4] FIG. 4 shows a configuration of a battery pack according to a fourth embodiment of the present invention. FIG. 4 shows an example of a specific configuration based on the principle of the third embodiment according to the present invention shown in FIG.

  4 includes a positive terminal 12, a negative terminal 13, a control terminal 21, a battery BT, a first transistor TR21, a second transistor TR22, a third transistor TR23, a first resistor R21, and a second resistor. R22 and a third resistor R23 are provided.

  The positive terminal 12, the negative terminal 13, and the control terminal 21 are exactly the same as those in FIG. The battery BT is, for example, a combination of a plurality of batteries, as in the case of FIG. 2, and is substantially the same as the battery 11 of FIG.

  The transistors TR21, TR22, and TR23 are switching elements, and in this case, are configured by FETs whose source and drain are on / off controlled by the gate potential.

  The transistor TR21 has a source connected to the positive electrode of the battery BT, a drain connected to the positive electrode terminal 12, and a gate connected to the source via the resistor R23. The transistor TR22 has a source connected to the gate of the transistor TR21, a drain connected to the control terminal 21, and a gate connected to the positive electrode of the battery BT, that is, the source of the transistor TR21 via the resistor R22. The transistor TR23 has a drain connected to the gate of the transistor TR22, a source connected to the negative electrode and the negative electrode terminal 13 of the battery BT, and a gate connected to the positive electrode of the battery BT, that is, the source of the transistor TR21 via the resistor R21. . The gate of the transistor TR23 is also connected to the drain of the transistor TR21, that is, the positive electrode terminal 12.

  The transistors TR21, TR22 and TR23 and the resistors R21, R22 and R23 form a switch circuit corresponding to the switch circuit 22 in FIG.

  In the battery pack of FIG. 4, normally, since the gate of the transistor TR12 is connected to the source of the transistor TR12 via the resistor R23, the transistor TR12 is turned off, and it is impossible to output power from the positive electrode terminal 12. Can not. Since the gate of the transistor TR23 is connected to the positive electrode of the battery BT via the resistor R21, the transistor TR23 is on. Therefore, the gate of the transistor TR22 is connected to the negative electrode of the battery BT, and the source of the transistor TR22 is connected to the positive electrode of the battery BT via the resistor R23, so that the transistor TR22 is on. Therefore, when the control terminal 21 and the negative terminal 13 are short-circuited, the gate voltage of the transistor TR21 becomes 0 V, the transistor TR21 is turned on, and the power of the battery BT can be output from the positive terminal 12. become.

  In this state, when the positive electrode terminal 12 and the negative electrode terminal 13 are short-circuited, the gate voltage of the transistor TR23 becomes 0 V, becomes the same potential as the source of the transistor TR23, and the transistor TR23 is turned off. Then, since the gate of the transistor TR22 is connected to the positive electrode of the battery BT via the resistor R22, the gate potential becomes higher than the source potential of the transistor TR22, and the transistor TR22 is turned off. When the transistor TR22 is turned off, the gate of the transistor TR21 is disconnected from the control terminal 21, so that the gate potential of the transistor TR21 becomes equal to the source potential of the transistor TR21, and the transistor TR21 is turned off.

  In this manner, when the transistor TR22 is turned off, the gate of the transistor TR21 is disconnected from the control terminal and connected to the positive electrode of the battery BT via the resistor R23, and the transistor TR21 is turned off. Protected from.

[Embodiment 5] FIG. 5 shows a basic configuration of a battery pack according to a fifth embodiment of the present invention.

The battery pack 3 shown in FIG. 5 includes a battery 11, a positive terminal 12, a negative terminal 13, and a control terminal 21 similar to those shown in FIG.
Is provided. FIG. 5 also shows a positive terminal 23, a negative terminal 24, a control terminal 25, a voltage sense terminal 34, and the like on the device 4 side to which the battery pack 3 is mounted.

As in the case of FIG. 3, the battery 11 includes a predetermined number of batteries, for example, a rechargeable secondary battery such as a nickel-metal hydride battery, and is connected between the positive electrode and the negative electrode to obtain a required voltage. ing. The positive terminal 12 and the negative terminal 13 are terminals for connecting the output of the battery 11 to the outside of the battery pack, that is, to a device serving as a load. The control terminal 21 is connected to the switch circuit 3
2 is a terminal for controlling the device 2 from the device 4 side.

  The voltage sense terminal 31 is a terminal that enables the voltage of the battery 11 to be detected from the device 4 even when the switch circuit 32 is off. The switch circuit 32 is interposed between the positive electrode of the battery 11 and the positive electrode terminal 12, and is turned on / off in response to the potential of the control terminal 21, and operates between the positive electrode and the positive electrode terminal 12 of the battery 11. Connection / disconnection. In the switch circuit 32, the control terminal 21 and the voltage sense terminal 31 are short-circuited via the control terminal 25 and the voltage sense terminal 34 on the device 4 side, and the potential of the control terminal 21 is substantially equal to the potential of the positive electrode of the battery 11. It turns on when it reaches the potential, and turns off otherwise. Further, in the switch circuit 32, similarly to the switch circuit 22 in FIG. 3, even when the control terminal 21 and the voltage sense terminal 31 are short-circuited, the potential of the positive terminal 12 is substantially equal to the potential of the negative electrode of the battery 11. It turns off when the potential drops.

  The positive terminal 23, the negative terminal 24, the control terminal 25, and the voltage sense terminal 34 of the device 4 are connected to the positive terminal 12, the negative terminal 13, and the control terminal 21 of the battery pack 3 when the battery pack 3 is mounted on the device 4, respectively. And voltage sense terminal 31. The control terminal 25 and the voltage sense terminal 34 of the device 4 are short-circuited on the device 4 side.

  The battery pack 3 of FIG. 5 is configured to be detachable from the device, and a switch circuit 22 provided on the positive electrode side of the battery 11 operates in response to the potential of the control terminal 21. In the battery pack 3 shown in FIG. 5, the switch circuit 32 is turned on when the control signal of the control terminal 21 is substantially at the positive potential, and the switch circuit 32 is turned off in other cases. It is turned off when the terminal 12 has almost reached the negative potential.

  That is, when the battery pack 3 is removed from the device 4, the switch circuit 32 is normally off, and when the battery pack 3 is mounted on the device 4, the connection between the control terminal 21 and the voltage sense terminal 31 is established. As a result of the short-circuit, the power is turned on, and a voltage is supplied from the positive terminal 12 to the device 2 through the positive terminal 23.

  When the control terminal 21 is not connected to the positive potential, the switch circuit 32 is off, so that even if the positive terminal 12 and the negative terminal 13 are short-circuited, the battery 11 does not short-circuit. When the control terminal 21 is connected to the positive electrode potential and the switch circuit 32 is turned on, the potential of the positive terminal 12 decreases when the positive terminal 12 and the negative terminal 13 are short-circuited. Turns off. Therefore, the battery 11 is protected from a short circuit between the positive electrode and the negative electrode.

[Embodiment 6] FIG. 6 shows a configuration of a battery pack according to a sixth embodiment of the present invention. FIG. 6 shows an example of a specific configuration based on the principle of the fifth embodiment according to the present invention shown in FIG.

  6 includes a positive terminal 12, a negative terminal 13, a control terminal 21, a voltage sense terminal 31, a battery BT, a first transistor TR31, a second transistor TR32, a first resistor R31, and a second resistor R32. And a third resistor R33.

  The positive electrode terminal 12, the negative electrode terminal 13, the control terminal 21, and the voltage sense terminal 31 are exactly the same as those in FIG. The battery BT is, for example, a combination of a plurality of batteries, as in the case of FIG. 2, and is substantially the same as the battery 11 of FIG.

  The transistors TR31 and TR32 are switch elements, and in this case, are configured by FETs whose on-off is controlled between the source and the drain by the gate potential.

  The transistor TR31 has a source connected to the positive electrode of the battery BT, a drain connected to the positive electrode terminal 12, and a gate connected to the source via the resistor R32. The transistor TR32 has a source connected to the negative electrode and the negative electrode terminal 13 of the battery BT, a drain connected to the gate of the transistor TR31, and a gate connected to the negative electrode of the battery BT, that is, the negative electrode terminal 13 via the resistor R33. Further, the gate of the transistor TR32 is directly connected to the control terminal 21 and also connected to the drain of the transistor TR31, that is, the positive electrode terminal 12 via a diode D31 having the illustrated polarity. The voltage sense terminal 31 is connected to the positive electrode of the battery BT, that is, the source of the transistor TR31 via the resistor R31.

  The transistors TR31, TR32 and TR33 and the resistors R31, R32 and R33 constitute a switch circuit corresponding to the switch circuit 32 in FIG. The resistor R31 corresponds to the resistor 33 in FIG.

  In the battery pack of FIG. 6, since the gate of the transistor TR32 is normally connected to the source of the transistor TR32 via the resistor R33, the transistor TR32 is off. Since the gate of the transistor TR31 is connected to the source of the transistor TR31 via the resistor R32, the transistor TR31 is off, and the power of the battery BT cannot be output from the positive terminal 12. When the control terminal 21 is connected to the voltage sense terminal 31, the gate voltage of the transistor TR32 becomes a voltage obtained by dividing the voltage of the battery BT by the resistors R31 and R33. If the resistance values of the resistors R31 and R33 are set in advance so that this voltage can turn on the transistor TR32, the transistor TR32 is turned on, and the gate voltage of the transistor TR31 becomes 0 V. When the transistor TR31 is turned on, the power of the battery BT can be output from the positive electrode terminal 12.

  Although it seems to be a rare case, in this state, when the positive terminal 12 and the negative terminal 13 are short-circuited, a current flows through the diode D31 and the potential of the gate of the transistor TR32 decreases. Therefore, the transistor TR32 is turned off, the gate potential of the transistor TR31 becomes equal to the source potential, and the transistor TR31 is turned off.

[Embodiment 7] FIG. 7 shows a configuration of a basic battery protection device according to a seventh embodiment of the present invention. FIG. 7 shows a battery protection device including the battery pack 1 having the configuration shown in FIG. 3 and a device 5 to which the battery pack 1 is attached.

The battery pack 1 includes a battery 11, a positive terminal 12, a negative terminal 13, a control terminal 21, and a first switch circuit 22, as shown in FIG. The battery 11 includes a predetermined number of batteries, for example, a rechargeable secondary battery such as a nickel-metal hydride battery, and is connected between a positive electrode and a negative electrode to obtain a required voltage. The positive electrode terminal 12 and the negative electrode terminal 13 are terminals for connecting the output of the battery 11 to the outside of the battery pack 1, that is, to a device serving as a load.

The control terminal 21 is a terminal for controlling the first switch circuit 22 from the device 5 side. The first switch circuit 22 is interposed between the positive electrode of the battery 11 and the positive terminal 12, and is turned on / off in response to the potentials of the positive terminal 12 and the control terminal 21, so that the positive electrode of the battery 11 is turned off. Connection / disconnection between the power supply and the positive electrode terminal 12. The switch circuit 22 is turned on when the control terminal 21 and the negative terminal 13 are short-circuited and the potential of the control terminal 21 decreases to a potential substantially equal to the potential of the negative electrode of the battery 11, and is turned off otherwise. Further, even when the control terminal 21 and the negative terminal 13 are short-circuited, the switch circuit 22 is turned off when the potential of the positive terminal 12 decreases to a potential substantially equal to the potential of the negative electrode of the battery 11.

  The device 5 has the same positive terminal 23, negative terminal 24 and control terminal 25 as the device 2 shown in FIG. 3, and further includes a second switch circuit 41. The second switch circuit 41 turns on / off between the control terminal 25 and the negative terminal 24 of the device 5 in response to a control signal inside the device 5.

  The battery pack 1 in FIG. 7 is configured to be detachable from the device 5, and the first switch circuit 22 provided on the positive electrode side of the battery 11 operates in response to the potential of the control terminal 21. In the battery pack 1, the switch circuit 22 is turned on when the potential of the control terminal 21 is substantially equal to the negative potential, and the switch circuit 22 is turned off in other cases. It turns off when the potential of the negative electrode is reached.

  That is, when the battery pack 1 is detached from the device 5, the switch circuit 22 is normally turned off, the battery pack 1 is mounted on the device 5, and the switch circuit 41 is activated by an internal control signal. When turned on, the control terminal 21 and the negative terminal 13 are short-circuited to be turned on, and a voltage is supplied from the positive terminal 12 to the device 5 via the positive terminal 23. That is, the switch circuit 22 is short-circuited between the control terminal 21 and the negative electrode terminal 13 even if the battery pack 1 is mounted on the device 5 and the switch circuit 41 is turned off by the internal control signal. That is, the switch circuit 22 is turned off, and there is no power supply from the positive terminal 12 into the device 5.

  In this way, even when the battery pack 1 similar to that of FIG. 3 is mounted on the device 5, the switch circuit 41 is turned on / off by the control signal inside the device 5, thereby turning on / off the switch circuit 22. Can be done.

[Eighth Embodiment] FIG. 8 shows a configuration of a battery pack according to an eighth embodiment of the present invention. FIG. 8 shows an example of a specific configuration based on the principle of the seventh embodiment of the present invention shown in FIG.

  FIG. 8 shows a battery protection device including a battery pack 6 having substantially the same configuration as that of FIG. 4 and a device 7 to which the battery pack 6 is attached. 8 includes a positive terminal 12, a negative terminal 13, a control terminal 21, a sense terminal 42, a battery BT, a first transistor TR21, a second transistor TR22, a third transistor TR23, and a first resistor R21. , A second resistor R22, a third resistor R23, and a fourth resistor R24.

  Each of the transistors TR21 to TR23 is a switch element, and in this case, is configured by an FET whose on-off is controlled between the source and the drain by a gate potential. The transistor TR21 has a source connected to the positive electrode of the battery BT, a drain connected to the positive electrode terminal 12, and a gate connected to the source via the resistor R23. The transistor TR22 has a source connected to the gate of the transistor TR21, a drain connected to the control terminal 21, and a gate connected to the positive electrode of the battery BT, that is, the source of the transistor TR21 via the resistor R22. The transistor TR23 has a drain connected to the gate of the transistor TR22, a source connected to the negative electrode and the negative electrode terminal 13 of the battery BT, and a gate connected to the positive electrode of the battery BT, that is, the source of the transistor TR21 via the resistor R21. . The gate of the transistor TR23 is also connected to the drain of the transistor TR21, that is, the positive electrode terminal 12. The sense terminal 42 is connected to the positive electrode of the battery BT, that is, the source of the transistor TR21 via the resistor R24.

  The device 7 includes a positive terminal 23, a negative terminal 24, a control terminal 25, a sense terminal 43, a fourth transistor TR24, a fifth transistor TR25, a sixth transistor TR26, a fifth resistor R25, a sixth resistor R26, A seventh resistor R27 and an eighth resistor R28 are provided.

  Each of the transistors TR24 to TR26 is a switching element, and in this case, is configured by an FET whose on / off is controlled between the source and the drain by a gate potential. The transistor TR24 has a source connected to the negative terminal 24, a drain connected to the control terminal 25, and a gate connected to the positive terminal 23 via the resistor R28. The gate of the transistor TR24 is also connected to the negative electrode potential (ground) at the same potential as the negative electrode terminal 24 via the resistor R25. The transistor TR25 has a source connected to the sense terminal 43, a drain connected to the gate of the transistor TR24, and a gate connected to the positive terminal 23. The gate of the transistor TR25 is also connected to the negative potential via the resistor R27. The transistor TR26 has a source connected to the negative potential, a drain connected to the gate of the transistor TR24, and a gate connected to the negative potential via the resistor R26. The control signal inside the device 7 is given to the gate of the transistor TR26.

  Each of the transistors TR21 to TR26 is a switching element, and in this case, is configured by an FET whose on / off state is controlled between a source and a drain by a gate potential. The positive terminal 23, the negative terminal 24, the control terminal 25 and the sense terminal 43 of the device 7 are connected to the positive terminal 12, the negative terminal 13, the control terminal 21 and the sense terminal of the battery pack 6 when the battery pack 6 is mounted on the device 7. The terminals 42 are respectively connected.

  When the battery pack 6 in FIG. 8 is just mounted on the device 7, the transistor TR21 is off, so that power cannot be supplied from the positive terminal 12 to the device. The battery voltage is applied to the source of the transistor TR25 from the positive electrode of the battery BT via the resistor R24, and the gate of the transistor TR25 is connected to the negative potential via the resistor R27, so that the transistor TR25 is turned on. The gate voltage of the transistor TR24 is a voltage obtained by dividing the output voltage of the battery BT by the resistors R24 and R25, and both resistance values are set in advance so that this voltage becomes a voltage for turning on the transistor TR24. As a result, the transistor TR24 is turned on. When the transistor TR24 is turned on, the connection between the control terminal 25 and the negative terminal 24, that is, between the control terminal 21 and the negative terminal 13, is connected, so that the power of the battery BT is output from the positive terminal 12.

  Since the gate voltage of the transistor TR25 becomes the voltage of the battery BT, the transistor TR25 is turned off. However, the gate voltage of the transistor TR24 becomes a voltage obtained by dividing the output voltage of the battery BT by the resistors R28 and R25. By setting both resistance values in advance so that the voltage turns on the transistor TR24, the transistor TR24 remains on.

  When a voltage that can turn on the transistor TR26 is applied to the gate of the transistor TR26 as a control signal from inside the device 7, the transistor TR26 is turned on, the gate voltage of the transistor TR24 becomes 0 V, and the transistor TR24 Is turned off, and the transistor TR21 in the battery pack 6 can be turned off. By setting the control signal to high impedance or 0 V, the transistor TR26 is turned off and the transistor TR24 is turned on, so that the transistor TR21 can be turned back on.

[Embodiment 9] FIG. 9 shows the configuration of a basic battery protection device according to a ninth embodiment of the present invention.

FIG. 9 shows a battery protection device including the battery pack 3 having the configuration shown in FIG. 5 and a device 8 to which the battery pack 3 is attached. As shown in FIG. 5, the battery pack 3 includes a battery 11, a positive terminal 12, a negative terminal 13, a control terminal 21, a voltage sense terminal 31, a first switch circuit 32, and a resistor 33.

  The battery 11 includes a predetermined number of batteries, for example, a rechargeable secondary battery such as a nickel-metal hydride battery, and is connected between a positive electrode and a negative electrode to obtain a required voltage. The positive electrode terminal 12 and the negative electrode terminal 13 are terminals for connecting the output of the battery 11 to the outside of the battery pack 3, that is, to a device serving as a load.

  The control terminal 21 is a terminal for controlling the first switch circuit 32 from the device 8 side. The voltage sense terminal 31 is a terminal that enables the voltage of the battery 11 to be detected from the device 4 even when the switch circuit 32 is off.

  The first switch circuit 32 is interposed between the positive electrode of the battery 11 and the positive electrode terminal 12, and is turned on / off in response to the potential of the control terminal 21, so that the positive electrode and the positive electrode Connection / disconnection between The switch circuit 32 is turned on when the control terminal 21 and the voltage sense terminal 31 are short-circuited and the potential of the control terminal 21 becomes substantially equal to the potential of the positive electrode of the battery 11, and is turned off otherwise. Furthermore, even when the control terminal 21 and the voltage sense terminal 31 are short-circuited, the switch circuit 32 is turned off when the potential of the positive terminal 12 drops to a potential substantially equal to the potential of the negative electrode of the battery 11.

  The device 8 has the same positive terminal 23, negative terminal 24, control terminal 25, and voltage sense terminal 34 as the device 4 shown in FIG. 5, and further includes a second switch circuit 51.

  The second switch circuit 51 turns on / off the connection between the control terminal 25 of the device 8 and the voltage sense terminal 34 in response to a control signal inside the device 8. The battery pack 3 in FIG. 9 is configured to be detachable from the device 8, and the first switch circuit 22 provided on the positive electrode side of the battery 11 operates in response to the potential of the control terminal 21. In the battery pack 3, the switch circuit 32 is turned on when the potential of the control terminal 21 is substantially the positive potential, and the switch circuit 32 is turned off in other cases. It turns off when the potential of the negative electrode is reached.

  That is, when the battery pack 3 is removed from the device 8, the switch circuit 32 is normally turned off, the battery pack 3 is mounted on the device 8, and the switch circuit 51 is activated by an internal control signal. When turned on, the control terminal 21 and the voltage sense terminal 31 are short-circuited to be turned on, and a voltage is supplied from the positive terminal 12 to the device 8 via the positive terminal 23. That is, even if the battery pack 3 is mounted on the device 8, the switch circuit 32 is short-circuited between the control terminal 21 and the voltage sense terminal 31 if the switch circuit 51 is turned off by the internal control signal. The switch circuit 32 is turned off, and there is no power supply from the positive terminal 12 into the device 8.

  In this way, even when the battery pack 3 similar to that shown in FIG. 5 is mounted on the device 8, the switch circuit 51 is turned on / off by the control signal inside the device 8, thereby turning on / off the switch circuit 32. Can be done.

[Embodiment 10] FIG. 10 shows a configuration of a battery pack according to a tenth embodiment of the present invention. FIG. 10 shows a specific configuration example based on the principle of the ninth embodiment of the present invention shown in FIG.

  FIG. 10 shows a battery protection device including a battery pack 9 having substantially the same configuration as that of FIG. 6 and a device 10 to which the battery pack 9 is attached. 10 includes a positive terminal 12, a negative terminal 13, a control terminal 21, a voltage sense terminal 31, a battery BT, a first transistor TR31, a second transistor TR32, a first resistor R31, and a second resistor. R32 and a third resistor R33 are provided.

  The transistors TR31 and TR32 are switch elements, and in this case, are configured by FETs whose on-off is controlled between the source and the drain by the gate potential.

  The transistor TR31 has a source connected to the positive electrode of the battery BT, a drain connected to the positive electrode terminal 12, and a gate connected to the source via the resistor R32. The transistor TR32 has a source connected to the negative electrode and the negative electrode terminal 13 of the battery BT, a drain connected to the gate of the transistor TR31, and a gate connected to the negative electrode of the battery BT, that is, the negative electrode terminal 13 via the resistor R33. Further, the gate of the transistor TR32 is directly connected to the control terminal 21 and also connected to the drain of the transistor TR31, that is, the positive electrode terminal 12 via a diode D31 having the illustrated polarity. The voltage sense terminal 31 is connected to the positive electrode of the battery BT, that is, the source of the transistor TR31 via the resistor R31.

  The device 10 includes a positive terminal 23, a negative terminal 24, a control terminal 25, a voltage sense terminal 34, a third transistor TR33, a fourth transistor TR34, a fourth resistor R34, a fifth resistor R35, and a sixth resistor R36. Is provided.

  The transistors TR33 and TR34 are switch elements, and in this case, are configured by FETs whose on-off is controlled between the source and the drain by the gate potential.

  The transistor TR33 has a source connected to the negative terminal 24, a drain connected to the control terminal 25, and a gate connected to the negative potential via the resistor R35. A resistor R34 is connected between the positive terminal 23 and the voltage control terminal 25. The transistor TR34 has a source connected to the voltage sense terminal 34, a drain connected to the control terminal 25, and a gate connected to the positive terminal 23. The gate of the transistor TR34 is also connected to the negative potential via the resistor R36. The control signal inside the device 10 is given to the gate of the transistor TR33.

  The transistors TR33 and TR34 are switch elements, and in this case, are configured by FETs whose on-off is controlled between the source and the drain by the gate potential.

  The positive terminal 23, the negative terminal 24, the control terminal 25, and the voltage sense terminal 34 of the device 10 are connected to the positive terminal 12, the negative terminal 13, the control terminal 21, and the It is connected to each of the voltage sense terminals 31.

When the battery pack 9 in FIG. 10 is just mounted on the device 10, the transistor TR31 is turned off, so that power cannot be supplied to the device 10 from the positive terminal 12. Since the voltage of the battery BT is applied to the source of the transistor TR34 by the resistor R34, and the gate of the transistor 34 is connected to the negative potential via the resistor R36, the transistor TR34 is turned on. Therefore, the control terminal 21 and the voltage sense terminal 31 are connected via the control terminal 25 and the voltage sense terminal 34, respectively, so that power is supplied from the positive electrode terminal 12. Since the gate voltage of the transistor TR34 becomes the voltage of the battery BT, the transistor TR34 is turned off, but the control terminal 25 is connected to the positive terminal 23 via the resistor R34, and the gate voltage of the transistor TR32 is A voltage obtained by dividing the voltage of the battery BT by the resistor R34 and the resistor R33 is set in advance to be a voltage for turning on the transistor TR32, so that the transistor TR32 remains on. .

  When a voltage that can turn on the transistor TR33 is applied as a control signal, the transistor TR33 is turned on, and the voltage of the control terminal 21 becomes 0V. Therefore, the transistor TR32 is turned off, and the transistor TR31 can be turned off. By setting the control signal to high impedance or 0 V, the transistor TR33 is turned off and the transistor TR32 is turned on, so that the transistor TR31 can be turned back on.

  In addition, the present invention is not limited to a battery pack and a battery protection device using a rechargeable secondary battery, and a battery pack using a primary battery such as a dry battery can be similarly protected. It is possible.

FIG. 1 is a block diagram illustrating a basic configuration of a battery pack according to a first embodiment of the present invention. It is a block diagram showing composition of a battery pack by a 2nd embodiment of the present invention. It is a block diagram showing composition of a fundamental battery pack by a 3rd embodiment of the present invention. It is a block diagram showing composition of a battery pack by a 4th embodiment of the present invention. It is a block diagram showing composition of a fundamental battery pack by a 5th embodiment of the present invention. FIG. 14 is a block diagram illustrating a configuration of a battery pack according to a sixth embodiment of the present invention. It is a block diagram showing the composition of the fundamental battery protection device by a 7th embodiment of the present invention. It is a block diagram showing the composition of the battery protection device by an 8th embodiment of the present invention. It is a block diagram showing the composition of the fundamental battery protection device by a 9th embodiment of the present invention. It is a block diagram showing the composition of the battery protection device by a 10th embodiment of the present invention. FIG. 9 is a block diagram for explaining a configuration of a conventional battery pack.

Explanation of reference numerals

1, 3, 6, 9 ... battery packs 2, 4, 5, 8, 7, 10 ... equipment 11, BT ... batteries 12, 23 ... positive electrode terminals 13, 24 ... negative electrode terminals 14, 22, 32, 41, 51 ... Switch circuits 21, 25 Control terminals 31, 34 Voltage sense terminals 33, R11, R12, R21 to R28, R31 to R36 Resistors 42, 43 Sense terminals TR11, TR12, TR21 to TR26, TR31 to TR34 Transistor D31 …diode

Claims (8)

A battery having a positive electrode and a negative electrode,
A positive terminal for device connection,
A negative electrode terminal for device connection, connected to a negative electrode of the battery,
When the potential of the positive electrode terminal drops so as to be substantially equal to the negative electrode of the battery, disconnect the positive electrode terminal and the positive electrode of the battery; otherwise, disconnect the positive terminal and the positive electrode of the battery. A battery pack, comprising: switch means for conducting electricity. The switch means
A first switch for turning on and off between a positive electrode terminal and a positive electrode of the battery;
If the positive terminal and the negative terminal are not externally short-circuited, they are turned off by the potential of the positive electrode of the battery, and turned on by the potential of the positive terminal falling to a potential substantially equal to the negative electrode of the battery. 2. The battery pack according to claim 1, further comprising a second switch that turns off the first switch by applying a control voltage to the first switch. A battery having a positive electrode and a negative electrode,
A positive terminal for device connection,
A negative electrode terminal for device connection, connected to a negative electrode of the battery,
Control terminal for device connection,
When the potential of the control terminal is reduced so as to be substantially equal to the negative electrode of the battery, conduction is established between the positive terminal and the positive electrode of the battery, and otherwise, between the positive terminal and the positive electrode of the battery. And a switch means for disconnecting the battery pack. The switch means
A first switch for turning on and off between a positive electrode terminal and a positive electrode of the battery;
The control terminal is enabled in the on state, and the control terminal can be turned on by controlling the control terminal to drop to a potential substantially equal to the negative electrode of the battery. A second switch for forcibly turning off the first switch;
If the positive terminal, the control terminal, and the negative terminal are not short-circuited externally, they are turned on by the potential of the positive electrode of the battery, and the positive terminal drops to a potential substantially equal to the negative electrode of the battery. The method according to claim 3, further comprising: a third switch that is controlled to be turned off by a potential of a negative electrode of the battery and that controls the second switch to be turned off by a potential of a positive electrode of the battery. Battery pack. A battery having a positive electrode and a negative electrode,
A positive terminal for device connection,
A negative electrode terminal for device connection, connected to a negative electrode of the battery,
Control terminal for device connection,
A voltage sensing terminal for device connection, to which a potential is supplied from a positive electrode of the battery,
When the voltage sense terminal and the control terminal are short-circuited externally, the potential of the positive electrode of the battery given to the control terminal causes conduction between the positive terminal and the positive electrode of the battery, And a switch for disconnecting the positive electrode terminal from the positive electrode of the battery at other times. The switch means
A first switch for turning on and off between a positive electrode terminal and a positive electrode of the battery;
Controlled by the potential of the control terminal, which is turned on when the control terminal is connected to the potential of the positive electrode of the battery, to turn on the first switch, and otherwise, the potential of the negative electrode of the battery. The battery pack according to claim 5, further comprising: a second switch that is turned off by the first switch to turn off the first switch. A battery having a positive electrode and a negative electrode, a positive electrode terminal, a negative electrode terminal connected to the negative electrode of the battery, a control terminal, and the positive electrode terminal when the potential of the control terminal drops so as to be substantially equal to the negative electrode of the battery. And the positive terminal of the battery pack having first switch means for disconnecting the positive terminal of the battery from the positive terminal of the battery at other times. Load means that operates on power supplied from the
A second switch means provided in connection with the load means and short-circuiting / disconnecting between the control terminal and the negative terminal of the battery pack by a control signal supplied from the load means side; apparatus. A battery having a positive electrode and a negative electrode; a positive terminal; a negative terminal connected to the negative electrode of the battery; a control terminal; a voltage sense terminal to which a potential is supplied from the positive electrode of the battery; the voltage sense terminal; A terminal between the positive terminal of the battery and the positive terminal of the battery is electrically connected to the control terminal when the terminal is short-circuited externally, and the positive terminal is used at other times. And load means operating with power supplied from the positive terminal and the negative terminal of the battery pack having first switch means for disconnecting between the positive electrode of the battery and the first switch means,
A battery protection device provided in connection with the load means, comprising: a second switch means for short-circuiting and disconnecting the control terminal and the sense terminal of the battery pack by a control signal supplied from the load means side. apparatus.

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