Charging apparatus and charging method
First Claim
1. A charging apparatus for charging a cell group, in which a plurality of secondary cells are connected in series, by supplying a charging current to the cell group, comprising:
- a discharge amount detection means for detecting an amount of power discharged from the cell group in a non-charging state;
a charge amount detection means for detecting an amount of power charged into the cell group in a charging state; and
a charging control means for, during a charging period, charging while reducing the charging current every time a charging voltage of any one of the secondary cells exceeds a specified overcharge protection voltage set lower than a full charge voltage until the charging current is reduced to a lower limit charging current value indicating that the respective secondary cells of the cell group are close to a fully charged state, then continuing charging with a current value equal to or smaller than the lower limit charging current value to increase the charging voltages of the respective secondary cells above the overcharge protection voltage, and stopping charging when the amount of power charged into the cell group by the charging becomes equal to the amount of power discharged from the cell group in the non-charging state.
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Accused Products
Abstract
The present invention aims to reliably prevent overcharge by carrying out charging in just proportion during charging periods.
A charging apparatus 1 for charging a secondary cell 22 by supplying a charging current Ic thereto is provided with a discharge amount detector 62 for detecting an amount of power discharged from the secondary cell in a non-charging state, a charge amount detector 60 for detecting an amount of power charged into the secondary cell in a charging state, and a charger controller 10 for stopping charging when the amount of charged power (charge amount Wc) becomes equal to the amount of discharged power (discharge amount Wc) during a charging period.
19 Citations
4 Claims
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1. A charging apparatus for charging a cell group, in which a plurality of secondary cells are connected in series, by supplying a charging current to the cell group, comprising:
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a discharge amount detection means for detecting an amount of power discharged from the cell group in a non-charging state; a charge amount detection means for detecting an amount of power charged into the cell group in a charging state; and a charging control means for, during a charging period, charging while reducing the charging current every time a charging voltage of any one of the secondary cells exceeds a specified overcharge protection voltage set lower than a full charge voltage until the charging current is reduced to a lower limit charging current value indicating that the respective secondary cells of the cell group are close to a fully charged state, then continuing charging with a current value equal to or smaller than the lower limit charging current value to increase the charging voltages of the respective secondary cells above the overcharge protection voltage, and stopping charging when the amount of power charged into the cell group by the charging becomes equal to the amount of power discharged from the cell group in the non-charging state. - View Dependent Claims (2, 3)
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4. A charging method for charging a cell group, in which a plurality of secondary cells are connected in series, by supplying a charging current to the cell group, comprising the steps of:
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detecting amounts of power discharged from the secondary cells in a non-charging state; and during a charging period, charging while reducing the charging current every time a charging voltage of any one of the secondary cells exceeds a specified overcharge protection voltage set lower than a full charge voltage until the charging current is reduced to a lower limit charging current value indicating that the respective secondary cells of the cell group are close to a fully charged state, then continuing charging with a current value equal to or smaller than the lower limit charging current value to increase the charging voltages of the respective secondary cells above the overcharge protection voltage, and stopping charging when the amount of power charged into the cell group by the charging becomes equal to the amount of power discharged from the cell group in the non-charging state.
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Specification