Method and device for reducing memory effect of battery

• US 5,942,878 A
• Filed: 09/09/1997
• Issued: 08/24/1999
• Est. Priority Date: 01/26/1996
• Status: Expired due to Fees

• Current Assignee: Yamaha Hatsudoki Kabushiki Kaisha (Yamaha Corporation)
• Original Assignee: Yamaha Hatsudoki Kabushiki Kaisha (Yamaha Corporation)
• Inventors: Ito, Masaki
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): LUK, LAWRENCE W
• Application Number:
  US08/913,677
• Time in Patent Office: 714 Days
• Field of Search: 320/131, 320/132, 320/DIG. 19, 320/DIG. 21
• US Class Current: 320/131
• CPC Class Codes: H02J 7/0069 Charging or discharging for charge maintenance, battery initiation or rejuvenation
• CPC Class Codes: H02J 7/0071 with a programmable schedule
• CPC Class Codes: H02J 7/04 Regulation of charging current or voltage
• 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: Y10S 320/21 State of charge of battery

Abstract

According to the invention, the discharge depth representing the ratio of discharged capacity relative to the rated discharge capacity of a battery is divided into a plurality of ranges with each range allocated with the number of charges at which a refresh discharge should be carried out. The discharge depth is obtained as a sum of discharged capacity between one charge and the next. At the time of charging, summing up the count of the number of charges in the corresponding range according to the discharge depth is repeated until the number of charges in any of the ranges reaches the number at which the refresh discharge should be carried out. Then the refresh discharge is carried out either automatically or manually. Since the discharge depth is divided into a plurality of ranges with each range allocated with the number of charges at which the refresh discharge should be carried out and the refresh discharge is carried out when the number of charges in any of the ranges reaches the allocated number, the refresh discharge is carried out at an appropriate timing at which the effect of the refresh discharge is most efficiently used either automatically or manually so that the influence of the memory effect is effectively and efficiently reduced.

Claims

1. A method of reducing the memory effect in storage batteries by effecting a refresh discharge at appropriate times during charging operations, said method comprising the steps of setting a discharge depth representing the ratio of discharged capacity of the storage battery to the rated capacity of the storage battery, allocating the discharge depths into a plurality of ranges, allocating the number of charges at which a refresh discharge should be carried out to each of the ranges, calculating the discharge depth by summing up the discharged capacity between one charge and the next, counting the number of charges upon each charge, and effecting a refresh discharge when the number of charges at which the refresh discharge should be carried out is reached.

2. A method of reducing the memory effect in storage batteries of claim 1, characterized in that an alarm is given to carry out a refresh discharge when the allocated number of charges for each range is reached.

5. A method of reducing the memory effect in storage batteries of claim 1, characterized in that a refresh discharge is performed automatically when the allocated number of charges for each range is reached.

3. A device for reducing the memory effect in storage batteries by effecting a refresh discharge during a charging operation, said device comprising refresh discharge setting means for setting a number of discharge depths each representing the ratio of discharged capacity relative to the rated capacity of the storage battery and dividing them into a plurality of ranges, means for setting the number of charges to each of the ranges at which number a refresh discharge should be carried out, discharged capacity summing means for summing up the discharged capacity between one charge and the next, discharge depth calculation means for calculating the discharge depth from the summed up discharged capacity of the storage battery and the rated capacity of the storage battery, counting means for counting the number of charges at the time of charging, and means for carrying out a refresh discharge when the number of charges at which the refresh discharge should be carried out is reached.

4. A device for reducing the memory effect in storage batteries of claim 3, further including alarm means for giving an alarm when the set number of charges is reached.

6. A device for reducing the memory effect in storage batteries of claim 3, further including automatic refresh discharge means for actuating said refresh discharge means when the set number of charges is reached.