Apparatus and method for balanced charging of a multiple-cell battery pack
First Claim
1. A method for balancing charge levels comprising:
- using a battery pack having a plurality of cells arranged in series;
bridging around a first cell of the plurality of cells with a bypass resistor and a switch;
monitoring a charge level of one of the cells based upon an input connected across the first cell, including comparing a relative voltage potential across the first cell with respect to a reference voltage potential and wherein the step of comparing includes providing cell monitor/regulator includes a voltage divider connected across the first cell and having an output connected to a first input of the comparator, and a reference voltage source that outputs the voltage potential to a second input of the comparator;
closing the switch when the charge level of the first cell equals a maximum value so as to shunt charge current around the cell through the bypass resistor;
connecting an output of the comparator to a lead of the switch, the switch closing a path through the bridge when the comparator measures a voltage at the second input greater than a voltage at the first input;
saturating a transistor in response to an output of the comparator when the comparator measures a voltage at the second input greater than a voltage at the first input; and
locating battery pack terminals at respective opposing ends of the series of the plurality of the cells, and connecting respective opposing leads of a charging circuit to the terminals at predetermined times so as to charge the plurality of cells.
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Accused Products
Abstract
An apparatus and method for charging a multiple-cell battery pack provides a balanced charge to each cell in a series by providing a cell charge monitor/regulator for (1) monitoring the charge (potential, for example) of each cell and, when a state is attained, defining a maximum cell charge, and (2) shunting further charge current to a next cell in the series via a shunt resistor that bridges the cell, and thereby bypasses further charging thereof, while directing shunted charge current to one or more next cells in the series as needed. Each of the cells is thereby charged to its fullest potential while the overall charging procedure is not unduly lengthened. The battery pack can be implanted as part of a life-saving system.
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Citations
11 Claims
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1. A method for balancing charge levels comprising:
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using a battery pack having a plurality of cells arranged in series; bridging around a first cell of the plurality of cells with a bypass resistor and a switch; monitoring a charge level of one of the cells based upon an input connected across the first cell, including comparing a relative voltage potential across the first cell with respect to a reference voltage potential and wherein the step of comparing includes providing cell monitor/regulator includes a voltage divider connected across the first cell and having an output connected to a first input of the comparator, and a reference voltage source that outputs the voltage potential to a second input of the comparator; closing the switch when the charge level of the first cell equals a maximum value so as to shunt charge current around the cell through the bypass resistor; connecting an output of the comparator to a lead of the switch, the switch closing a path through the bridge when the comparator measures a voltage at the second input greater than a voltage at the first input; saturating a transistor in response to an output of the comparator when the comparator measures a voltage at the second input greater than a voltage at the first input; and locating battery pack terminals at respective opposing ends of the series of the plurality of the cells, and connecting respective opposing leads of a charging circuit to the terminals at predetermined times so as to charge the plurality of cells. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for balancing charge levels comprising:
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using a battery pack having a plurality of cells arranged in series; bridging around a first cell of the plurality of cells with a bypass resistor and a switch; monitoring a charge level of one of the cells based upon an input connected across the first cell, including comparing a relative voltage potential across the first cell with respect to a reference voltage potential and wherein the step of comparing includes providing cell monitor/regulator includes a voltage divider connected across the first cell and having an output connected to a first input of the comparator, and a reference voltage source that outputs the voltage potential to a second input of the comparator; closing the switch when the charge level of the first cell equals a maximum value so as to shunt charge current around the cell through the bypass resistor; connecting an output of the comparator to a lead of the switch, the switch closing a path through the bridge when the comparator measures a voltage at the second input greater than a voltage at the first input; saturating a transistor in response to an output of the comparator when the comparator measures a voltage at the second input greater than a voltage at the first input; and monitoring each of the cells based upon an input connected across each of the cells for measuring a charge of the each of the cells respectively, and providing a bridge around the each of the cells, the bridge including a respective bypass resistor and a respective switch and closing the respective switch when the charge of the each of the cells equals a maximum value so as to shunt charge current around the each of the cells through the respective bypass resistor.
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10. A transcutaneous energy transmission (TET) system adapted for implantation in a body and for powering an implanted life-saving device comprising:
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an implanted TET module for receiving energy through the skin and transmitting electricity derived from the energy to a life-saving device; and an implanted rechargeable battery pack including a battery pack having a plurality of series-arranged cells, having a bridge connected around a first cell, including a bypass resistor in series with a switch, and a cell monitor/regulator having an input connected across the first cell for measuring a charge of the first cell, wherein the cell monitor/regulator closes the switch when a charge of the first cell equals a maximum value. - View Dependent Claims (11)
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Specification