Secondary battery apparatus

• US 6,307,353 B1
• Filed: 12/08/2000
• Issued: 10/23/2001
• Est. Priority Date: 12/10/1999
• Status: Expired due to Fees

• Current Assignee: Toshiba Battery Co., Ltd. (Toshiba Corporation)
• Original Assignee: Toshiba Battery Co., Ltd. (Toshiba Corporation)
• Inventors: Shiojima, Nobuo
• Primary Examiner(s): TOATLEY, GREGORY J
• Application Number:
  US09/731,725
• Time in Patent Office: 319 Days
• Field of Search: 320/139, 320/162
• US Class Current: 320/139
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H02J 7/0071 with a programmable schedule
• CPC Class Codes: H02J 7/00711 with introduction of pulses during the charging process
• CPC Class Codes: H02J 7/007194 of the battery
• CPC Class Codes: Y02B 40/00 Technologies aiming at improving the efficiency of home appliances, e.g. induction cooking or efficient technologies for refrigerators, freezers or dish washers
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A secondary battery apparatus includes a secondary battery, a battery voltage detector, a temperature rising rate detector and a charge controller. The charge controller starts pulse charging of the secondary battery which is performed by turning on/off a switch element located in a charge path of the secondary battery at predetermined periods when a terminal voltage of the secondary battery exceeds a first set voltage during charging of the secondary battery, stops the pulse charging while maintaining the switch element in a conductive state after the time the terminal voltage, observed at a particular time within a switch element blocking period during the pulse charging, exceeds a second set voltage, and blocks the switch element to stop charging the secondary battery when the temperature rising rate detector detects the secondary battery having reached a fully charged state during the charging subsequent to the pulse charging. As a result, the secondary battery is reliably and efficiently charged to the fully charged state in a short time without being affected by fluctuations in a charge current or an ambient temperature.

Claims

1. A secondary battery apparatus comprising:

a secondary battery;

a switch element provided in series in a charge circuit of said secondary battery;

a voltage detector for detecting a terminal voltage of said secondary battery;

a full charge detector for detecting said secondary battery having reached a fully charged state; and

a charge controller for controlling charging of said secondary battery by conducting or blocking said switch element, said charge controller including;

a pulse charging starting unit for starting a conducting/blocking operation of said switch element at predetermined intervals to start pulse charging said secondary battery when the terminal voltage exceeds a first set voltage during the charging of said secondary battery;

a pulse charging stopping unit for stopping said pulse charging while maintaining said switch element in a conductive state when the terminal voltage has reached a second set voltage during a switch element blocking period of said pulse charging; and

a charge stopping unit for blocking said switch element to stop charging subsequent to said pulse charging when said full charge detector detects the fully charged state of said secondary battery during the charging subsequent to said pulse charging.

2. The secondary battery apparatus according to claim 1, wherein said charge controller blocks said switch element when the terminal voltage of said secondary battery has reached an abnormally high third set voltage during the charging of said secondary battery.

3. The secondary battery apparatus according to claim 1, wherein said full charge detector comprises a temperature sensor for detecting a temperature of said secondary battery, and detects said secondary battery having reached the fully charged state when the battery temperature detected by said temperature sensor has reached a set temperature, or when an increase in said battery temperature exceeds a set value, or when a rising rate per time of said battery temperature exceeds a set value.

4. The secondary battery apparatus according to claim 1, wherein said full charge detector detects that said secondary battery has reached the fully charged state when the terminal voltage of said secondary battery detected by said voltage detector has reached a set voltage, or when a peak of a voltage change is detected, or when a predetermined voltage drop is detected after the peak of the voltage change has been detected.

5. The secondary battery apparatus according to any of claims 1 through 4, wherein said charge controller conducts said switch element when the terminal voltage of said secondary battery is equal to or below a predetermined voltage, or when a discharge state of said secondary battery is detected.