Apparatus and method of rapidly charging nickel-cadmium batteries
First Claim
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1. An apparatus for rapidly charging nickel-cadmium batteries comprising:
- a current feeding means which feeds a charging current to a cell that needs be charged;
a temperature measuring means which measures the temperature of said cell;
a sampling means which controls said temperature measuring means to measure the temperature of said cell and stores the data thereof or outputs the data thereof to an arithmetic means;
an arithmetic means which performs calculations on the temperature data of said cell obtained by said sampling means and outputs a control signal that represents a period for discontinuing the charging operation;
a switching means which discontinues the supply of current to the cell from the current feeding means in response to said output from said arithmetic means; and
a control means for controlling each of said means;
wherein said current feeding means in said charging apparatus feeds a current of at least 2 C to said cell during said charging operation; and
said arithmetic means has a first arithmetic function that calculates the rate of temperature increase of said cell from the temperature data of said cell obtained by said sampling means through the temperature measuring means, a second arithmetic function which calculates a rate of change by comparing the rate of temperature increase of said cell in a first period with the rate of temperature increase of said cell in a second period, and a third function which compares the rate of temperature increase of said cell in said second period with the rate of temperature increase of said cell in said first period in order to judge whether the rate of temperature increase of said cell in said second period is more than two times as great as the rate of temperature increase of said cell in said first period, and outputs a signal for discontinuing the supply of a charging current to said cell based on the result of said judgement.
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Abstract
A method and apparatus for charging nickel-cadmium batteries with a current greater than 2C rate. The cell temperature or both the temperature and voltage thereof are monitored, and the charging operation is halted upon detection of a moment when the rate of temperature increase of the cell became at least twice as great as the rate of temperature increase that was measured just before, or of a moment at which the above phenomenon took place and a moment at which the rate of voltage increase has declined immediately following a period during which the rate of voltage increase has continually risen.
39 Citations
12 Claims
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1. An apparatus for rapidly charging nickel-cadmium batteries comprising:
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a current feeding means which feeds a charging current to a cell that needs be charged; a temperature measuring means which measures the temperature of said cell; a sampling means which controls said temperature measuring means to measure the temperature of said cell and stores the data thereof or outputs the data thereof to an arithmetic means; an arithmetic means which performs calculations on the temperature data of said cell obtained by said sampling means and outputs a control signal that represents a period for discontinuing the charging operation; a switching means which discontinues the supply of current to the cell from the current feeding means in response to said output from said arithmetic means; and a control means for controlling each of said means; wherein said current feeding means in said charging apparatus feeds a current of at least 2 C to said cell during said charging operation; and said arithmetic means has a first arithmetic function that calculates the rate of temperature increase of said cell from the temperature data of said cell obtained by said sampling means through the temperature measuring means, a second arithmetic function which calculates a rate of change by comparing the rate of temperature increase of said cell in a first period with the rate of temperature increase of said cell in a second period, and a third function which compares the rate of temperature increase of said cell in said second period with the rate of temperature increase of said cell in said first period in order to judge whether the rate of temperature increase of said cell in said second period is more than two times as great as the rate of temperature increase of said cell in said first period, and outputs a signal for discontinuing the supply of a charging current to said cell based on the result of said judgement. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 11, 12)
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10. A method of rapidly charging nickel-cadmium batteries comprising:
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a current feeding means which feeds a charging current to a cell that needs be charged; a temperature measuring means for measuring the temperature of the cell; a sampling means which measures the temperature of the cell and stores the data thereof or outputs the data thereof to an arithmetic means; an arithmetic means which calculates the temperature data of the cell obtained by said sampling means and outputs a control signal representative of a time for discontinuing the charging operation; a switching means responsive to the output of said arithmetic means and discontinues the supply of current from said current feeding means to said cell; and a control means for controlling all of the above said means; wherein said current feeding means in said charging apparatus feeds a current of at least 2C to said cell during the charging operation; and said arithmetic mean has; a first step of calculating the rate of temperature increase of the cell from the temperature data of the cell obtained by said sampling means via the temperature measuring means; a second step for calculating the rate of change by comparing the rate of temperature increase of the cell in a first period with the rate of temperature increase of the cell in a following second period; and a third step which compares the rate of temperature increase of the cell in the second period with the rate of temperature increase of the cell in the first period, judges whether the rate of temperature increase of the cell in the second period is greater than two fold of the rate of temperature increase of the cell in the first period, and outputs a signal for discontinuing the supply of charging current to the cell based on the judged result.
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Specification