Method of controlling charge and discharge of secondary battery for automatic guided vehicle

• US 7,193,394 B2
• Filed: 05/28/2004
• Issued: 03/20/2007
• Est. Priority Date: 06/13/2003
• Status: Expired due to Fees

• Current Assignee: Panasonic EV Energy Company, Limited (Toyota Motor Corporation)
• Original Assignee: Panasonic EV Energy Company, Limited (Toyota Motor Corporation)
• Inventors: Fujioka, Noriyuki, Morishita, Nobuyasu, Ohkawa, Kazuhiro, Ueda, Toshifumi
• Primary Examiner(s): Tso; Edward H.
• Application Number:
  US10/856,535
• Publication Number:
  US 20040251870A1
• Time in Patent Office: 1,026 Days
• Field of Search: 320/132, 320127-128, 320/104, 320/148, 320/150, 320/131
• US Class Current: 320/128
• CPC Class Codes: B60L 53/00 Methods of charging batteries, specially adapted for electric vehicles; Charging stations or on-board charging equipment therefor; Exchange of energy storage elements in electric vehicles
• CPC Class Codes: B60L 53/11 DC charging controlled by the charging station, e.g. mode 4
• CPC Class Codes: H02J 7/0071 with a programmable schedule
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 90/12 Electric charging stations
• CPC Class Codes: Y02T 90/14 Plug-in electric vehicles

Abstract

To provide a method of controlling charge and discharge of a secondary battery for automatic guided vehicle that can decide the timing of refresh charge and discharge accurately and minimize the frequency of refresh charge and discharge. The method of controlling charge and discharge of a secondary battery for automatic guided vehicle comprises a first discharge step of making the secondary battery drive an automatic guided vehicle and discharge electricity with a predetermined amount; a voltage measurement step of measuring a discharge end voltage of the secondary battery at the completion of the first discharge step; and a charge step of performing a first charge step of charging the secondary battery incompletely at a first charging current value when the discharge end voltage is higher than a preset minimum voltage, and performing a second charge step of discharging the secondary battery fully and then charging the secondary battery fully at a second charging current value smaller than the first charging current value when the discharge end voltage equals the preset minimum voltage or less.

Claims

1. A method of controlling charge and discharge of a secondary battery for automatic guided vehicle comprising:

a first discharge step of making the secondary battery drive an automatic guided vehicle and discharge electricity with a predetermined amount;

a voltage measurement step of measuring a discharge end voltage of said secondary battery at the completion of said first discharge step; and

a charge step of performing a first charge step of charging said secondary battery incompletely at a first charging current value when said discharge end voltage is higher than a preset minimum voltage, and performing a second charge step of discharging said secondary battery fully and then charging said secondary battery fully at a second charging current value smaller than said first charging current value when said discharge end voltage equals said preset minimum voltage or less.

2. A method of controlling charge and discharge of a secondary battery for automatic guided vehicle as stated in claim 1, wherein, in said first charge step, voltage and temperature of said secondary battery are monitored continuously, a preset charge end voltage is decided based on said temperature and charge is finished when said voltage equals said preset charge end voltage or more.

3. A method of controlling charge and discharge of a secondary battery for automatic guided vehicle as stated in claim 2, wherein said preset charge end voltage is decided based on said first charging current value and said temperature.

4. A method of controlling charge and discharge of a secondary battery for automatic guided vehicle as stated in claim 1, wherein said second charge step is finished after a predetermined period from start of charge.

5. A method of controlling charge and discharge of a secondary battery for automatic guided vehicle as stated in claim 1, wherein, in said second charge step, temperature of said secondary battery is monitored continuously and charge is finished when a rate of increase per unit of time in said temperature equals a predetermined value or more.

6. A method of controlling charge and discharge of a secondary battery for automatic guided vehicle as stated in claim 1, wherein said secondary battery is a nickel metal hydride battery.