Secondary battery control circuit

• US 7,502,700 B2
• Filed: 02/10/2004
• Issued: 03/10/2009
• Est. Priority Date: 03/16/1999
• Status: Expired due to Fees

• Current Assignee: Godo Kaisha IP Bridge 1 (IP Bridge, Inc.)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Iwaizono, Yoshinori
• Primary Examiner(s): Feliciano; Eliseo Ramos
• Assistant Examiner(s): OMALLEY, MARY CATHERINE
• Application Number:
  US10/708,115
• Publication Number:
  US 20040162698A1
• Time in Patent Office: 1,855 Days
• Field of Search: 702/57, 702 63- 65, 702/99, 702/130, 702132-133, 702/136, 702/188, 702182-183, 320/152, 320/162, 320/112, 320/107, 320151-154, 320/137, 320/134, 320/128, 320/130, 320/150, 429 61- 62, 429 56- 57, 429/59, 429/90, 429/92, 340/636.1, 340/636.19, 340/636.21
• US Class Current: 702/63
• CPC Class Codes: H02J 7/00302 Overcharge protection
• CPC Class Codes: H02J 7/0031 using battery or load disconnect circuits H02J9/002 takes precedence
• CPC Class Codes: H02J 7/007194 of the battery

Abstract

According to the present invention, there is provided a secondary battery control circuit which can perform a reliable charge/discharge control without activating Positive Temperature Coefficient element. The secondary battery control circuit includes a temperature detection section for detecting a temperature of the secondary battery and a system logic for controlling charging/discharging of the secondary battery based on the temperature detected by the temperature detection section. The system logic interrupts the charging of the secondary battery in a case where the temperature detected by the temperature detection section is out of a predetermined first temperature range, and interrupts the discharging of the secondary battery in a case where the temperature detected by the temperature detection section is out of a predetermined second temperature range.

Claims

1. A secondary battery control unit, comprising:

a liquid detection section for continuously detecting infiltration or generation of a liquid inside a secondary battery or inside a battery pack in which the secondary battery is installed; and

a control section for interrupting charging/discharging of the secondary battery in a case where a liquid is detected by the liquid detection section,

wherein the liquid detection section controls the control section based on an impedance or resistance value detected between two electrically separated terminals, and wherein an amount of an electrical current flowing through each of the terminals approaches zero, unless the liquid is detected by the liquid detection section, and

wherein the liquid detection section includes a comparator having a first input connected to a constant current source and one of the terminals, and a second input connected to a reference voltage source.

2. The secondary battery control circuit according to claim 1 further comprising a temperature detection section for detecting a temperature of the secondary battery, wherein the control section controls charging/discharging of the secondary battery based on the temperature detected by the temperature detection section.

3. The secondary battery control circuit according to claim 1, wherein the secondary battery control circuit is formed on a single semiconductor chip.

4. A The secondary battery control circuit according to claim 3, wherein the single semiconductor chip is enclosed in a sealing section of the secondary battery.

5. The secondary battery control unit according to claim 1, wherein the electrically separated terminals are separated by a distance of about 0.1 millimeters.