Charging system for multi-cell battery
First Claim
1. A battery charging system for charging a battery of cells connected in series with one another, said system comprising:
- a charging means for charging said battery, and for controlling a charging current;
a voltage detecting means for detecting a terminal voltage of each of said cells;
a constant voltage means for controlling the terminal voltage of each cell by causing the charging current of each cell to bypass in accordance with the terminal voltage detected by said voltage detecting means;
a current saturation detecting means for detecting a saturation of a bypass current caused by said constant voltage means; and
a controlling means for controlling said charging means so as to decrease the charging current in accordance with an output of said current saturation detecting means;
wherein said charging means includes a means for performing a constant current charging operation, and said controlling means includes a means for decreasing the charging current of the charging means stepwise in accordance with an output of said saturation detecting means; and
wherein said controlling means includes a means for decreasing the charging current by a predetermined amount of decrease at each of stepwise decreases, and said amount of decrease is equal to or greater than a bypass current capacity of said constant voltage means, and equal to or smaller than double the bypass current capacity.
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Accused Products
Abstract
A battery charging system is arranged to reduce a bypass capacity and to enable a charging operation with high current. A plurality of single battery cells 1 connected in series is connected to a charger 6, and each cell is connected in parallel with a constant voltage circuit 4 having a constant voltage control section 2 and a current saturation detecting section 3. The constant voltage control section 2 detects the terminal voltage, compares the detected terminal voltage with a preset voltage, and control the terminal voltage so as to be held constant by causing the charging current to bypass in accordance with the error resulting from the comparison. The current saturation detecting section 3 sends a command signal through an OR circuit to the charger 6 when the bypass current becomes saturated, and the charger 6 reduces the charging current in response to the command signal. Therefore, the capacity of the bypass current can be set at a lower level, and the high current charging is possible.
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Citations
19 Claims
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1. A battery charging system for charging a battery of cells connected in series with one another, said system comprising:
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a charging means for charging said battery, and for controlling a charging current; a voltage detecting means for detecting a terminal voltage of each of said cells; a constant voltage means for controlling the terminal voltage of each cell by causing the charging current of each cell to bypass in accordance with the terminal voltage detected by said voltage detecting means; a current saturation detecting means for detecting a saturation of a bypass current caused by said constant voltage means; and a controlling means for controlling said charging means so as to decrease the charging current in accordance with an output of said current saturation detecting means; wherein said charging means includes a means for performing a constant current charging operation, and said controlling means includes a means for decreasing the charging current of the charging means stepwise in accordance with an output of said saturation detecting means; and wherein said controlling means includes a means for decreasing the charging current by a predetermined amount of decrease at each of stepwise decreases, and said amount of decrease is equal to or greater than a bypass current capacity of said constant voltage means, and equal to or smaller than double the bypass current capacity. - View Dependent Claims (2)
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3. A battery charging system for a battery of cells connected in series with one another, said system comprising:
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a charging means for charging said battery, and for controlling a charging current; a voltage detecting means for detecting a terminal voltage of each of said cells; a constant voltage means for controlling the terminal voltage of each cell by causing the charging current of each cell to bypass; a current saturation detecting means for detecting a saturation of a bypass current caused by said constant voltage means; a logic circuit for producing a saturation signal in response to at least one output signal of said current saturation detecting means; and a controlling means for controlling said charging means so as to decrease the charging current in accordance with said saturation signal outputted from said logic circuit; wherein said cells are divided into a plurality of blocks, and said logic circuit comprises a circuit for producing said saturation signal when at least one of said current saturation detecting means produces the output signal in each block. - View Dependent Claims (4, 5, 6)
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7. A battery charging system for charging a battery of series connected cells, said system comprising:
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a charging means for supplying a charging current to a series connection of said cells to charge said battery; a plurality of regulator circuits each of which is connected in parallel with a unique one of said cells and each of which comprises a regulating means for regulating a terminal voltage of the corresponding one of said cells by controlling a bypass current bypassing the corresponding one of said cells, and a commanding means for producing a command signal in accordance with the terminal voltage of the corresponding one of said cells; and a control means for causing said charging means to reduce said charging current in response to said command signal; wherein said regulating means of each of said regulator circuits comprises a voltage detecting means for detecting the terminal voltage, said voltage detecting means comprises a first comparing means for comparing the terminal voltage with a predetermined first voltage level, and said regulating means of each of said regulator circuits further comprises a bypass current controlling means for maintaining the terminal voltage substantially constant by decreasing a current flowing through the corresponding one of said cell by increasing the bypass current in accordance with an output signal produced by said first comparing means; and wherein said commanding means comprises a saturation detecting means for detecting a saturation of the bypass current by monitoring an increase of the terminal voltage from said first voltage level and for producing said command signal when the saturation of the bypass current is detected, and said saturation detecting means comprises a second comparing means for producing said command signal when the terminal voltage becomes equal to or higher than a second predetermined voltage level which is higher than said first voltage level. - View Dependent Claims (8, 9, 18, 19)
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10. A battery charging system for charging a battery of series connected cells, said system comprising:
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a charging means for supplying a charging current to a series connection of said cells to charge said battery; a plurality of regulator circuits each of which is connected in parallel with a unique one of said cells and each of which comprises a regulating means for regulating a terminal voltage of the corresponding one of said cells by controlling a bypass current bypassing the corresponding one of said cells, and a commanding means for producing a command signal in accordance with the terminal voltage of the corresponding one of said cells; and a control means for causing said charging means to reduce said charging current in response to said command signal; wherein said regulating means of each of said regulator circuits comprises a voltage detecting means for detecting the terminal voltage, and a bypass current controlling means for maintaining the terminal voltage substantially constant by decreasing a current flowing through the corresponding one of said cells by increasing the bypass current in accordance with the detected terminal voltage; and
wherein said commanding means includes a means for detecting a saturation of the bypass current by monitoring an increase of the terminal voltage, and for producing said command signal when the saturation of the bypass current is detected;wherein said control means comprises a logic circuit comprising a plurality of input terminals each of which is connected with a unique one of said regulator circuits, and a single output terminal for delivering an output signal for commanding a decrease of said charging current when said command signal is inputted to at least one of said input terminals; wherein each of said regulator circuits comprises a bypass circuit section for forming a current path bypassing the corresponding one of said cells;
said voltage detecting means comprises a first comparing means for comparing the terminal voltage with a predetermined first voltage level, and turning said bypass current controlling means form an off state for opening said bypass circuit section to an on state for closing said bypass circuit section when the terminal voltage is higher than said predetermined first voltage level; and
said commanding means includes a means for detecting the saturation of the bypass current by monitoring an increase of the terminal voltage from said first voltage level and producing said command signal when the saturation of the bypass current is detected; andwherein said commanding means comprises a second comparing means for producing said command signal when the terminal voltage becomes equal to or higher than a second predetermined voltage level which is higher than said first voltage level, and said control means includes a means for reducing said charging current in response to said command signal sent from at least one of said regulator circuits. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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Specification