Battery charging method and apparatus using initial charging step with gradually increasing charging current, quick charging step with large charging current and final charging step with decreasing charging current

• US 5,500,584 A
• Filed: 11/03/1993
• Issued: 03/19/1996
• Est. Priority Date: 02/17/1992
• Status: Expired due to Fees

• Current Assignee: Kiyomi Hanashiro
• Original Assignee: Kiyomi Hanashiro
• Inventors: Shimomoto, Kenkichi
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): TSO, EDWARD H
• Application Number:
  US08/129,153
• Time in Patent Office: 867 Days
• Field of Search: 320/20, 320/22, 320/23, 320/24, 320/39, 320/40
• US Class Current: 320/159
• CPC Class Codes: H02J 7/00714 in response to battery charging or discharging current
• CPC Class Codes: H02J 7/007182 in response to battery voltage

Abstract

A battery charging method for charging a battery such as a lead acid storage battery quickly, and a battery charging apparatus used in carrying out the battery charging method, includes an initial charging process between times 0 to t1, a quick charging process between times t1 to t2 and a final charging process between times t2 to t3, carried out step-wise and continuously. In the initial charging process, a charging current whose volume of electricity is increased gradually is applied. In the quick charging process, a charging current whose volume of electricity is larger than the initial charging process is applied intermittently to a battery while watching a voltage. In the final charging process, a charging current whose volume of electricity is reduced gradually is applied to the battery when the voltage has reached a charge-end voltage. Thereby, it is possible to charge in a very short time, and to penetrate the charging into electrodes without damaging the battery.

Claims

1. A battery charging method comprising the steps of:

an initial charging step of applying a first gradually increasing charging current, to start charging of a battery,

a monitoring step of monitoring the charging current in the initial charging step after elapse of a predetermined charging time, to provide a detected value,

a comparing step of comparing said detected value with a predetermined value,

a quick charging step of thereafter intermittently applying a second charging current which is larger than the first charging current, while monitoring a terminal voltage of the battery, to charge the battery to a charge-end voltage, when said detected value is greater than said predetermined value in said comparing step, said quick charging step including the steps alternately repeating;

a charging period during which an intermittent supply of the second charging current is continued, and

a charging suspension period during which the intermittent supply of the second charging current is suspended,

until the terminal voltage of the battery reaches the charge-end voltage, and

a final charging step of thereafter applying a gradually decreasing charging current, to finish charging of the battery.

2. A battery charging apparatus comprising:

a charging circuit for causing a charging current to flow to a battery;

a control switch connected to said charging circuit for selectively passing and cutting off the charging current flowing through said charging circuit to the battery;

a charging current detector connected to said charging circuit for detecting the charging current flowing through said charging circuit;

a terminal voltage detector connected to the battery for detecting a terminal voltage of the battery; and

a control unit which controls current supply to the charging circuit by supplying control signals to the control switch in response to detection by the charging current detector and the terminal voltage detector, said control unit including;

first signal generating means for controlling said control switch to cause a first gradually increasing charging current, to be supplied through the charging circuit to the battery, to start charging of the battery,

first judging means for comparing a value of said first charging current detected by the charging current detector with a reference value to determine a defect of the battery,

second signal generating means for controlling said control switch to intermittently cause a second charging current larger than the first charging current to be supplied through the charging circuit to the battery when the first gradually increasing charging current is greater than said reference value after elapse of a predetermined amount of time, to charge the battery to a charge-end voltage,

period setting means connected with the control switch for alternately setting a charging period during which the intermittent supply of said second charging current is continued, and a charging suspension period during which the intermittent supply of said second charging current is suspended, until the terminal voltage of the battery reaches the charge-end voltage, and

third signal generating means for controlling said control switch to cause a third gradually decreasing charging current, to be supplied through the charging circuit to the battery after said charge-end voltage has been reached by said second charging current, to finish charging of the battery.

3. A battery charging apparatus according to claim 2, further comprising switching means for controlling said first through third signal generating means to shift the operation from the first signal generating means to the second signal generating means when the first charging current detected by said charging current detector reaches a predetermined value, and for switching the operation from the second signal generating means to the third signal generating means when the detected voltage by said terminal voltage detector reaches said charge-end voltage.

4. A battery charging apparatus according to claim 3, further comprising:

second judging means for comparing a value of said terminal voltage detected by the terminal voltage detector with said charging-end voltage to determine that the terminal voltage of the battery has reached the charge-end voltage, and

said switching means controls said first through third signal generating means to shift the operation from the first signal generating means to the second signal generating means in response to said first judging means, and switches the operation from the second signal generating means to the third signal generating means in response to said second judging means.