Electricity: battery or capacitor charging or discharging – Battery or cell charging – With thermal condition detection
Patent
1996-10-29
1999-01-26
Wong, Peter S.
Electricity: battery or capacitor charging or discharging
Battery or cell charging
With thermal condition detection
320150, 320151, 320148, 320156, 320157, 320159, H02J 702
Patent
active
058642242
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a method for charging a secondary battery and a charger, the secondary battery being preferably used for a power supply of a motor-driven vehicle, such as a human-driven bicycle with an auxiliary power source.
BACKGROUND ART
Secondary battery, which is mounted on, for example, a human-driving vehicle with an auxiliary power source, is recharged by means of a battery charger connected to a domestic electrical outlet. Conventionally, Ni-Cd cells or the like are used for such a secondary battery.
In the charging of the Ni-Cd battery, the battery voltage is measured for controlling the charging. After the start of the charging, the battery voltage rises increasingly, and then becomes constant. After that, the voltage of the secondary battery B rises again and peaks once before the secondarybattery B is fully charged. After the peak, the voltage-drops continuously. When it is detected that the voltage of the secondary battery B drops by .DELTA.V from the peak value, the charging is controlled to be finished.
In addition to such a measurement of the battery voltage, the charging time may be counted by a timer. In this case, the charging is finished when the voltage-drop .DELTA.V has been detected, or when a prescribed time has passed.
It is known that charging of the Ni-Cd battery is affected by temperature very much. Therefore, in charging of the battery, it is possible that the lifetime of the battery is shortened if an appropriate control is not carried out on the basis of the temperature of the battery. However, such a charging method according to the battery temperature has not yet been proposed in fact.
DISCLOSURE OF INVENTION
It is, therefore, an object of the present invention to propose a method for charging a secondary battery in which lifetime of the secondary battery can be prolonged through an appropriate control depending on the battery temperature.
To resolve the above-described problem, according to the invention there is provided a method for charging a secondary battery, comprising steps of supplying a first current, which is generally constant, from a charging means to the secondary battery, and conditions is fulfilled: of a predetermined time period from start of the supplying of the first current; range; and the first current.
The invention is further characterized in that the method further comprises, after connecting of the secondary battery and the charging means, steps of checking as to whether the temperature of the secondary battery is in a predetermined range or not; and permitting to proceed to the step of supplying the first current insofar as the temperature of the secondary battery is in the predetermined range.
The invention is further characterized in that the method further comprises a step of supplying a second current, which is constant and lower than the first current, after stopping the supply of the first current for the reason of the condition (A) or (B).
The invention is further characterized in that the method further comprises steps of waiting until the temperature of the secondary battery falls to be below a predetermined level; and indicating that the charging has ended.
The invention is further characterized in that the method further comprises steps of checking as to whether the temperature of the secondary battery is in a predetermined range or not before and at the step of supplying the second current; and permitting to proceed to the step of supplying the second current insofar as the temperature of the secondary battery is in the predetermined range.
The invention is further characterized in that the method further comprises steps of waiting until the temperature of the secondary battery falls to be below a predetermined level after stopping the supply of the first current for the reason of the condition (C); and indicating that the charging has ended.
The invention is further characterized in that the method further comprises steps of checking as to whether the voltage of the secondary battery is above a
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European Search Report dated Jun 9, 1997.
Ono Tomohiro
Suzuki Masahito
Takechi Hiroaki
Shin K.
Wong Peter S.
Yamaha Hatsudoki Kabushiki Kaisha
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