Method and system for balancing cells with variable bypass current
AssigneeBoston-Power, Inc.
InventorsPer Onnerud, Chad Souza, Mark Gerlovin, Phillip E. Partin, Richard V. Chamberlain, II, Eckart W. Jansen
Life of this patent
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Abstract
A circuit for balancing battery cells includes a plurality of resistors configured in parallel with the battery cells, and a plurality of switches configured in series with the resistors. A control circuit causes the switches to balance the battery cells based on detected voltage of the battery cells and based on past operation of the cells.
Claims32
A system for balancing a plurality of battery cells, comprising:
- a) a plurality of battery cells connected in series, at least one of the battery cells including
- i) a resistor component configured in parallel with a battery cell, and
- ii) a switch configured in series with the resistor component;
- and
- b) a control circuit configured to cause the switch, based on a detected voltage of the battery cell, to partially discharge the battery cell and thereby balance the cell relative to another cell with which the cell is connected in series, the control circuit generating a pulse-width modulated (PWM) signal, corresponding to a selected balancing current, to the switch.
A method of balancing a plurality of battery cells, comprising the steps of:
- a) monitoring a voltage across a battery cell;
- b) selecting a balancing current;
- and
- c) generating a pulse-width modulated (PWM) signal to a switch configured in parallel to the battery cell to partially discharge the battery cell and thereby balance the battery cell relative to another battery cell with which the cell is connected in series, the PWM signal corresponding to the selected balancing current.
A system for balancing a plurality of battery cells, comprising:
- a) a plurality of battery cells connected in series, at least one of the battery cells including:
- i) a plurality of resistor components configured in parallel with a battery cell, the plurality of resistor components providing plural selectable resistances;
- ii) plurality of switches, each of the plurality of switches configured in series with one of the plurality of resistor components;
- and
- b) a control circuit configured to cause at least one of the plurality of switches, based on a detected voltage of the battery cell, to partially discharge the battery cell and thereby balance the cell relative to another cell with which the cell is connected in series, the control circuit selecting the at least one of the plurality of switches to generate a balancing current corresponding to a selected balancing current.
A system for balancing a plurality of battery cells, comprising:
- a) a plurality of battery cells connected in series, at least one of the battery cells including:
- i) a variable resistor component configured in parallel with a battery cell, the variable resistor component providing plural selectable resistances;
- ii) a switch configured in series with the variable resistor component;
- and
- b) a control circuit configured to cause the switch, based on a detected voltage of the battery cell, to partially discharge the battery cell and thereby balance the cell relative to another cell with which the cell is connected in series, the control circuit selecting a resistor value of the variable resistor to generate a balancing current corresponding to a selected balancing current.
Dependencies are inferred from the claim text.