Battery charging device

• US 6,404,167 B1
• Filed: 11/09/2000
• Issued: 06/11/2002
• Est. Priority Date: 11/10/1999
• Status: Expired due to Term

• Current Assignee: Makita Corporation
• Original Assignee: Makita Corporation
• Inventors: Sakakibara, Kazuyuki
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): Luk, Lawrence
• Application Number:
  US09/710,550
• Time in Patent Office: 579 Days
• Field of Search: 320/132, 320/130, 320/134, 320/149, 324/426, 324/431, 324/433
• US Class Current: 320/132
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm
• CPC Class Codes: G01R 31/3835 involving only voltage measurements
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: H02J 7/0049 Detection of fully charged condition

Abstract

The battery charging device obtains an open-circuit voltage at the time of 70% capacity based on information stored in a ROM of a battery package prior to the charge, and upon measuring an open-circuit voltage of the battery package by a voltage measuring portion, if this open-circuit voltage is higher than the obtained open-circuit voltage, a second indicator is switched ON to indicate that the remaining capacity is not less than 70% to thereby enable discrimination among batteries requiring charge or that do not prior to starting charging.

Claims

1. A battery charging device comprising:

determining means for determining, prior to start of a charging operation, whether an open-circuit voltage of batteries is higher than a specified value, and

indicating means for indicating that a capacity of the batteries is not less than a prescribed value in case the battery voltage is determined to be higher than the specified value.

4. The battery charging device as claimed in claim 1, further comprising an integrating means for integrating charge currents to the batteries, and

an integrated value judging means for judging whether charge has been performed up to a specified capacity by the integrating means,

wherein one of the indicating means indicates that a capacity of the batteries is not less than a prescribed value in case it is judged by the integrated value judging means that charge has been performed up to the specified capacity.

2. A battery charging device comprising:

an open-circuit voltage obtaining means for obtaining, based on an identifier provided on the battery side, an open-circuit voltage at the time the battery capacity is not less than a specified value,

determining means for determining, prior to start of a charging operation, whether a measured open-circuit voltage of batteries is higher than the open-circuit voltage as obtained by the open-circuit voltage obtaining means, and

indicating means for indicating that a capacity of the batteries is not less than a prescribed value in case the measured open-circuit voltage is determined to be higher than the obtained open-circuit voltage.

5. The battery charging device as claimed in claim 2, further comprising an integrating means for integrating charge currents to the batteries, and

an integrated value judging means for judging whether charge has been performed up to a specified capacity by the integrating means,

wherein one of the indicating means indicates that a capacity of the batteries is not less than a prescribed value in case it is judged by the integrated value judging means that charge has been performed up to the specified capacity.

3. A battery charging device comprising:

a memory means for storing maps, which are maps that are obtained through mapping based on temperatures and values of rises in temperature of batteries to obtain a permissible current value at which charge may be performed while restricting a rise in temperature of batteries, for setting the permissible current value to be small in case the temperature value is high and setting the permissible current value to be small in case the temperature rising value is low,

a temperature detecting portion for detecting a present temperature of the batteries,

a temperature rising value outputting means for obtaining the temperature rising value from the temperature as detected by the temperature detecting portion,

a permissible current value retrieving portion for retrieving maps in the memory means for obtaining the permissible value based on the temperature as detected by the temperature detecting portion and the temperature rising value output by the temperature rising value outputting means,

a charging portion for charging the batteries in a charging operation at the permissible current as retrieved by the permissible current value retrieving portion,

a capacity judging portion for judging during the charging operation whether the batteries have been charged up to a specified capacity on a basis of judgments whether a number of times in which the temperature as detected by the temperature detecting portion and the temperature rising value output by the temperature rising value outputting means fall within regions indicating a final stage of charge from among the map of the memory means is frequent or not, and indicating means for indicating during the charging operation that a capacity of the batteries is not less than a prescribed value based on the judgments of the capacity as obtained by the capacity judging portion.

6. The battery charging device as claimed in claim 3, further comprising an integrating means for integrating charge currents to the batteries, and

an integrated value judging means for judging whether charge has been performed up to a specified capacity by the integrating means,

wherein one of the indicating means indicates that a capacity of the batteries is not less than a prescribed value in case it is judged by the integrated value judging means that charge has been performed up to the specified capacity.

7. A battery charging device comprising:

a charge amount storage means for storing charge amounts to a memory means of the batteries during charging,

determining means for determining, prior to start of a charging operation, whether an open-circuit voltage of batteries is higher than a specified value, and

indicating means for indicating that a capacity of the batteries is not less than a prescribed value in case the battery voltage is higher than the specified value and a charge amount as stored in the memory means is high, and for indicating that a capacity of the batteries is not more than the prescribed value in case the charge amount as stored in the memory means is low though the battery voltage is higher than the specified value.