Protective apparatus for secondary battery

• US 5,252,411 A
• Filed: 09/25/1991
• Issued: 10/12/1993
• Est. Priority Date: 09/26/1990
• Status: Expired due to Term

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Yokokawa, Masaaki, Aita, Takayuki
• Primary Examiner(s): KALAFUT, STEPHEN J
• Application Number:
  US07/765,259
• Time in Patent Office: 748 Days
• Field of Search: 429/7.62, 320/36
• US Class Current: 429/62
• CPC Class Codes: H01M 10/443 in response to temperature
• CPC Class Codes: H02H 7/18 for batteries; for accumulators
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

Disclosed is a protective apparatus for a secondary battery comprising a temperature sensing switch turned on when the ambient temperature around the secondary battery exceeds a predetermined temperature setting, and a discharging circuit electrically connected via the temperature sensing switch to the secondary battery, the discharging circuit acting to discharge that battery. The discharging circuit contains a voltage sensing switch turned on when the voltage applied to the discharging circuit exceeds a predetermined discharge starting voltage, and a discharging resistor serially connected to the voltage sensing switch.

Claims

1. A protective apparatus for a secondary battery, said apparatus comprising:

a temperature sensing means for allowing current flow when the ambient temperature around said secondary battery exceeds a temperature setting; and

a discharging circuit electrically connected via said temperature sensing means to said secondary battery, said discharging circuit discharging said secondary battery;

said discharging circuit further comprising;

a voltage sensing switching means being switched on substantially when the voltage applied to said discharging circuit exceeds a predetermined discharge starting voltage; and

a discharging resistor serially connected to said voltage sensing switching means, said discharging resistor setting the discharge current in effect at the time of discharging.

2. A protective apparatus for a secondary battery according to claim 1, wherein said temperature sensing means is a bimetal switch.

3. A protective apparatus for a secondary battery according to claim 1, wherein said voltage sensing switching means at least comprises a voltage regulation diode.

4. A protective apparatus for a secondary battery according to claim 1, wherein said secondary battery is a nonaqueous electrolyte secondary battery.

5. A protective apparatus for a secondary battery according to claim 1, wherein said apparatus is incorporated in a battery pack.

6. A protective apparatus for a secondary battery according to claim 1, wherein said temperature sensing means is a thermistor.