Battery low capacity alarm device for use in an electric vehicle

• US 5,819,864 A
• Filed: 10/29/1997
• Issued: 10/13/1998
• Est. Priority Date: 01/30/1995
• Status: Expired due to Term

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group), Tokyo R & D Co., Ltd.
• Inventors: Takagi, Kunihiko, Koike, Yoshikazu, Kozaki, Minoru, Tadokoro, Kohichi
• Primary Examiner(s): Hurley, Kevin
• Application Number:
  US08/959,595
• Time in Patent Office: 349 Days
• Field of Search: 180/65.1, 180/65.3, 180/65.4, 180/65.8, 180/220, 340/636, 320/48, 324/435
• US Class Current: 180/65.1
• CPC Class Codes: B60L 15/10 for automatic control superimposed on human control to limit the acceleration of the vehicle, e.g. to prevent excessive motor current electric devices for safety purposes B60L3/00
• CPC Class Codes: B60L 15/20 for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed
• CPC Class Codes: B60L 3/00 Electric devices on electrically-propelled vehicles for safety purposes; Monitoring operating variables, e.g. speed, deceleration or energy consumption methods or circuit arrangements for monitoring or controlling batteries or fuel cells B60L58/00
• CPC Class Codes: B60L 50/60 using power supplied by batteries in combination with fuel cells B60L50/75
• CPC Class Codes: B60L 58/10 for monitoring or controlling batteries
• CPC Class Codes: B60L 58/18 of two or more battery modules
• CPC Class Codes: B62H 1/04 Substantially U-shaped stands for embracing the rear wheel
• CPC Class Codes: B62J 27/00 Safety equipment
• CPC Class Codes: B62K 2202/00 Motorised scooters
• CPC Class Codes: B62K 2204/00 Adaptations for driving cycles by electric motor for driving electrically assisted bicycles B62M6/00
• CPC Class Codes: B62M 7/12 with the engine beside or within the driven wheel
• CPC Class Codes: G01R 19/16542 for batteries charge condition monitoring in G01R31/36
• CPC Class Codes: G01R 31/006 on road vehicles, e.g. automobiles or trucks testing of ignition installations peculiar to internal combustion engines F02P17/00
• CPC Class Codes: G01R 31/3647 for determining the ability of a battery to perform a critical function, e.g. cranking
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility

Abstract

An alarm device is provided in an electric vehicle for indicating an insufficient remaining charge in a storage battery. The operation of both a remaining capacity meter and insufficient capacity alarm are continuously operated for a predetermined amount of time after a turn-off of a main power switch by means of a timer that is activated by the turn-off of the main switch when the storage battery suffers an insufficient capacity. The capacity of the storage battery is determined after the surface charge of the storage battery is eliminated when a charging operation is complete.

Claims

1. A remaining capacity insufficient alarm device for use in an electric vehicle which includes a storage battery, a power supply circuit for feeding electric power from the storage battery to a plurality of devices on the vehicle, a main switch for turning on and off the power supply circuit, the remaining capacity insufficient alarm device comprising:

means for measuring the remaining capacity of the storage battery and for issuing an alarm signal when the storage battery has an insufficient capacity;

alarm means for alerting a driver of insufficient capacity;

timer means for counting time for a predetermined duration of time in response to the turn-off operation of the main switch and for continuously issuing an activation signal for the predetermined duration of time after the turn-off operation of the main switch; and

prevention means, responsive to the activation signal from the timer means, for preventing the power supply circuit from cutting off power to, at least, the remaining capacity measuring means and the alarm means, whereby the alarming means and the remaining capacity measuring means remain operative for the predetermined duration of time after the turn-off operation of the main switch, so that the driver is alerted by the remaining capacity measuring means and the alarm means when the storage battery has an insufficient capacity.

2. A storage battery charge capacity measuring device for use in an electric vehicle which includes a storage battery, comprising:

determining means for, upon completion of a charging operation, measuring the terminal voltage across the storage battery at predetermined time intervals and determining whether the storage battery is in a surface charge state based on a variation in the terminal voltages measured at the predetermined time intervals;

surface charge eliminating means for allowing the storage battery to discharge on a light load when the storage battery is in a surface charge state; and

capacity determining means for determining charge capacity based on the terminal voltage after the surface charge state is eliminated.