Charger for use with a nickel-cadmium battery that uses charge and discharge cycles dependent on voltage and current

A charging device for charging a battery, comprising:

• a DC supply that supplies a direct current;
• a charging switch electrically connected to the DC supply and electrically connectable to a battery;
• a controller electrically connected to the charging switch to control the charging switch to selectively electrically connect the DC supply to the battery;
• a discharging assembly electrically connected to the controller and electrically connectable to the battery, wherein the discharging assembly is controlled by the controller for selective electrical connection with the battery to effect discharge of the battery;
• a voltage detection device electrically connected to the controller between the charging switch and the battery that detects voltage applied to the battery;
• and
• a current detection assembly electrically connected to the controller and connectable to the battery that detects current in the battery,
• wherein the controller controls the charging switch to stop charging the battery when the charging current detected by the current detection assembly reaches a predetermined current value, and
• wherein the controller controls the charging switch to consecutively charge the battery for a first period of time, discharge the battery for a second period of time and charge the battery for a third period of time, the periods of time being based on the detected voltage and the detected current.

A method of charging a battery, comprising the steps of:

• initially charging the battery by causing a charging current to flow in the battery to raise an internal voltage of the battery to predetermined first voltage and detecting a charging current flowing into the battery and stopping the charging of the battery when the detected charging current reaches a predetermined current value;
• discharging an electric charge of the battery charged to the predetermined first voltage by a predetermined voltage quantity to reduce the first voltage of the battery to a predetermined second voltage;
• and
• finally charging the battery by causing a charging current to flow in the discharged battery to again increase the internal voltage of the battery to the first voltage.

A charger for use with a Ni-Cd (Nickel-Cadmium) battery, comprising:

• charging means for causing a charging current to flow in the Ni-Cd battery and for increasing an internal voltage of the Ni-Cd battery to a predetermined first voltage to thereby charge the Ni-Cd battery;
• discharging means for discharging an electric charge from the Ni-Cd battery charged by said charging means by a predetermined voltage quantity to thereby reduce the first voltage of the Ni-Cd battery to a predetermined second voltage;
• controlling means coupled to said charging means and said discharging means for controlling the charging means to charge the Ni-Cd battery for at least initial and final charging periods and for controlling said discharging means to effect discharging during a period between the initial and final charging periods;
• voltage detecting means coupled to said controlling means for detecting the internal voltage of the Ni-Cd battery;
• and
• current detecting means coupled to said controlling means for detecting the charging current flowing in the Ni-Cd battery;
• wherein said controlling means controls said charging means to stop charging the Ni-Cd battery when the charging current detected by said current detecting means reaches a predetermined current value.