Battery system which prevents current from flowing during a short-circuiting of the battery terminals

• US 5,835,989 A
• Filed: 02/22/1995
• Issued: 11/10/1998
• Est. Priority Date: 02/24/1994
• Status: Expired due to Fees

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Nagai, Shinji
• Primary Examiner(s): Gaffin, Jeffrey A.
• Assistant Examiner(s): KAPLAN, JONATHAN STUART
• Application Number:
  US08/392,331
• Time in Patent Office: 1,357 Days
• Field of Search: 307/112, 307/113, 307/115, 307/116, 307/127, 307/150, 307/43, 307/85, 307/86, 307/125, 361/82, 361/84, 361/18, 320/13, 320/14, 320/49, 320/40, 320/30, 320/34, 320/36, 320/112, 320/114, 320/127, 320/110
• US Class Current: 307/116
• CPC Class Codes: H02H 7/18 for batteries; for accumulators
• CPC Class Codes: H02J 7/0031 using battery or load disconnect circuits H02J9/002 takes precedence

Abstract

A rechargeable battery package includes circuitry with a switching device which disconnects the exterior terminals of the battery package from one or more batteries therein. The circuit also includes a device having a diode function which allows the battery or batteries to be charged regardless of the state of the switching device. A power MOS-FET having a diode characteristic is used for the switching device and diode device. The gate of the power MOS-FET controls the disconnections of the batteries within the battery package. The gate is connected to a switch such as a reed relay contained within the battery package which is triggered by a magnet within a portable computer. Alternatively, a control terminal may be provided on the exterior of the battery package which is connected to the gate of the power MOS-FET.

Claims

1. An apparatus comprising:

a battery including first and second terminals;

a current switch including;

a first terminal connected to the first terminal of the battery,

a second terminal for supplying power to a device, and

a control terminal which controls a state of the current switch,

said current switch transmitting current between the first terminal and the second terminal in order for the battery to be discharged only when a conducting signal is applied to said control terminal of said current switch;

a magnet activated switch;

a battery pack housing which includes therein the battery, the magnet activated switch, and the current switch;

a first battery pack terminal, connected to the second terminal of the current switch, exposed to an exterior of the battery pack housing; and

a second battery pack terminal, connected to the second terminal of the battery, exposed to the exterior of the battery pack housing,

wherein the first battery pack terminal and the second battery pack terminal are both for supplying current to a device external to the battery pack housing from the battery and also for charging the battery,

the apparatus further comprising;

a diode connected across the first terminal and the second terminal of the current switch which allows current to flow between the first terminal and the second terminal in order to charge the battery pack regardless of the state of the switch,

wherein during a normal operation said conducting signal is supplied through the magnet activated switch to the control terminal when the battery pack housing is installed in a device including a magnet used to activate the magnet activated switch, and said conducting signal is not supplied to the control terminal when said magnet activated switch is not activated and the battery pack housing is not installed.

2. An apparatus according to claim 1, wherein said battery is a rechargeable battery.

3. An apparatus according to claim 1, wherein said battery is selected from a group, consisting of a NiCd battery and a NiMH battery.

4. An apparatus according to claim 1, wherein:

said current switch is a power MOS-FET; and

said control terminal of the current switch is a gate terminal of the power MOS-FET.

5. An apparatus according to claim 1, wherein:

said current switch is a power MOS-FET;

said control terminal of the current switch is a gate terminal of the power MOS-FET; and

said diode is included within the power MOS-FET.

6. An apparatus according to claim 1, wherein:

said current switch is a power MOS-FET; and

said control terminal of the current switch is a gate terminal of the power MOS-FET; and

said power MOS-FET includes a diode.

7. An apparatus according to claim 1, further comprising:

the device connected to the first terminal of the current switch.

8. An apparatus according to claim 1, wherein:

said first and second battery pack terminals are the only terminals for passing current to and receiving current from the battery.

9. An apparatus comprising:

a battery including first and second terminals;

a current switch including;

a first terminal connected to the first terminal of the battery,

a second terminal for supplying power to a device, and

a control terminal which controls a state of the current switch,

said current switch transmitting current between the first terminal and the second terminal in order for the battery to be discharged only when a conducting signal is applied to said control terminal of said current switch;

a battery pack housing which includes therein the battery;

a first battery pack terminal, connected to the second terminal of the current switch, exposed to an exterior of the battery pack housing;

a second battery pack terminal, connected to the second terminal of the battery, exposed to the exterior of the battery pack housing; and

a third battery pack terminal mounted on an exterior of the battery pack housing and connected to the control terminal of the current switch,

wherein the first battery pack terminal and the second battery pack terminal are both for supplying current to a device external to the battery pack housing from the battery and also for charging the battery,

the apparatus further comprising;

a diode connected across the first terminal and the second terminal of the current switch which allows current to flow between the first terminal and the second terminal in order to charge the battery pack regardless of the state of the switch,

wherein during a normal operation said conducting signal is supplied from the device through the third battery pack terminal to the control terminal of the current switch when the battery pack housing is installed, and said conducting signal is not supplied to the control terminal and the current switch is not activated when the battery pack housing is not installed.

10. An apparatus comprising:

a battery including first and second terminals;

a current switch including;

a first terminal connected to the first terminal of the battery,

a second terminal for supplying power to a device, and

a control terminal which controls a state of the current switch,

said current switch transmitting current between the first terminal and the second terminal in order for the battery to be discharged only when a conducting signal is applied to said control terminal of said current switch;

a battery pack housing which includes therein the battery and the current switch;

a first battery pack terminal, connected to the second terminal of the current switch, exposed to an exterior of the battery pack housing; and

a second battery pack terminal, connected to the second terminal of the battery, exposed to the exterior of the battery pack housing,

wherein the first battery pack terminal and the second battery pack terminal are both for supplying current to a device external to the battery pack housing from the battery and also for charging the battery,

the apparatus further comprising;

a diode connected across the first terminal and the second terminal of the current switch which allows current to flow between the first terminal and the second terminal in order to charge the battery pack regardless of the state of the switch,

wherein said battery and current switch comprise a first battery system, said apparatus further comprising;

a second battery system including;

a second battery; and

a second current switch including;

a first terminal connected to a terminal of the second battery,

second terminal for supplying power to the device, and

a control terminal which controls a state of the second current switch and,

said second current switch transmitting current between the first terminal and the second terminal thereof in order for the second battery to be discharged only when a second conducting signal is applied to said control terminal of said second current switch;

a microprocessor disposed in said device, connected to the control terminals of the first and second current switches, for generating the control signals applied to the control terminals of the current switches of the battery systems.

11. An apparatus comprising:

a battery including first and second terminals;

a current switch including;

a first terminal connected to the first terminal of the battery,

a second terminal for supplying power to a device, and

a control terminal which controls a state of the current switch,

said current switch transmitting current between the first terminal and the second terminal in order for the battery to be discharged only when a conducting signal is applied to said control terminal of said current switch;

a battery pack housing which includes therein the battery and the current switch;

a first battery pack terminal, connected to the second terminal of the current switch, exposed to an exterior of the battery pack housing; and

a second battery pack terminal, connected to the second terminal of the battery, exposed to the exterior of the battery pack housing,

wherein the first battery pack terminal and the second battery pack terminal are both for supplying current to a device external to the battery pack housing from the battery and also for charging the battery,

the apparatus further comprising;

a diode connected across the first terminal and the second terminal of the current switch which allows current to flow between the first terminal and the second terminal in order to charge the battery pack regardless of the state of the switch,

said apparatus further comprising the device connected to the first terminal of the current switch,

wherein said device is a portable computer having at least two components, a first of said components powered by the first battery system and a second of said components powered by the second battery system, wherein the microprocessor independently controls the first and second current switches.

12. A battery pack, comprising:

a battery including first and second terminals;

a control signal supplying means for supplying a control signal indicating that the battery may be discharged; and

switch means including;

a first terminal connected to the first terminal of the battery,

a second terminal for supplying power to a device, and

a control terminal, connected to the control signal supplying means, which controls a state of the switch means,

the switch means for preventing the battery from discharging unless the control signal is applied to the control terminal;

a battery pack housing which includes the battery and the switch means;

a first battery pack terminal, connected to the second terminal of the switch means, exposed to an exterior of the battery pack housing; and

a second battery pack terminal, connected to the second terminal of the battery, exposed to the exterior of the battery pack housing,

the battery pack further comprising;

diode means, connected between the first and second terminals of the switch means, for allowing the battery to be charged regardless of a state of the control signal supplied by the control means,

wherein the control signal supplying means comprises a magnet activated switch means wherein during a normal operation said conducting signal is supplied through the magnet activated switch means to the control terminal when the battery pack housing is installed in a device including a magnet used to activate the magnet activated switch means, and said conducting signal is not supplied to the control terminal when said magnet activated switch means is not activated and the battery pack housing is not installed.

13. A battery sack according to claim 12, wherein the switch means and said diode means are disposed in a power MOS-FET.

14. A battery pack according to claim 12, wherein:

said first and second battery pack terminals are the only terminals for passing current to and receiving current from the battery.

15. A battery pack, comprising:

a battery including first and second terminals;

a control signal supplying means for supplying a control signal indicating that the battery may be discharged; and

switch means including;

a first terminal connected to the first terminal of the battery,

a second terminal for supplying power to a device, and

a control terminal, connected to the control signal supplying means, which controls a state of the switch means,

the switch means for preventing the battery from discharging unless the control signal is applied to the control terminal;

a battery pack housing which includes the battery and the switch means;

a first battery pack terminal, connected to the second terminal of the switch means, exposed to an exterior of the battery pack housing; and

a second battery pack terminal, connected to the second terminal of the battery, exposed to the exterior of the battery pack housing,

the battery pack further comprising;

diode means, connected between the first and second terminals of the switch means, for allowing the battery to be charged regardless of a state of the control signal supplied by the control means,

wherein the control signal supplying means comprises said device, wherein during a normal operation said conducting signal is supplied from the device to the control terminal of the switch means when the battery pack housing is installed, and said conducting signal is not supplied to the control terminal and the switch means is not activated when the battery pack housing is not installed.