Abstract: A method and apparatus to detect cell voltage of each of a plurality of battery cells in a rechargeable battery pack is disclosed. The method comprises generating a square wave form with a positive phase and a negative phase, sending the square wave form to a first circuit that is connected to a battery cell and to a second circuit with matching components of the first circuit, and finally driving a matching voltage of the second circuit to become equivalent to the battery cell voltage for measurement.

Abstract: A method and apparatus to detect cell voltage of each of a plurality of battery cells in a rechargeable battery pack is disclosed. The method comprises generating a square wave form with a positive phase and a negative phase, sending the square wave form to a first circuit that is connected to a battery cell and to a second circuit with matching components of the first circuit, and finally driving a matching voltage of the second circuit to become equivalent to the battery cell voltage for measurement.

Abstract: A method and apparatus to detect cell voltage of each of a plurality of battery cells in a rechargeable battery pack is disclosed. The method comprises generating a wave form with a positive phase and a negative phase by a current limited square wave generator. The wave form is a square wave having a maximum peak-to-peak voltage when the square wave generator is not loaded to be current limited. Then, sending the positive phase of the wave form to a first loop from a capacitor to the positive side of a battery cell. And, sending the negative phase of the wave form to a second loop from the negative side of the battery cell toward the capacitor. Finally, detecting a change of an electrical signal from the square wave generator. The voltage detection method and apparatus of this invention can be applied to detect whether a rechargeable battery cell has voltage lower than a low voltage limit or to measure the voltage of the battery cell in order to check its status.

Abstract: A method and system to manage battery pack having a plurality of rechargeable battery cells connected in series is disclosed. The system comprises a plurality of identical voltage detection and charging modules, one for each of the plurality of battery cells. The system also comprises a multiplexer connected to and multiplexing each of the voltage detection and charging modules. Each of the modules has one or two wires connecting to the positive side of its corresponding battery cell and another set of one or two wires connecting to the negative side of the battery cell.

Abstract: A method and apparatus to detect cell voltage of each of a plurality of battery cells in a rechargeable battery pack is disclosed. The method comprises generating a wave form with a positive phase and a negative phase by a current limited square wave generator. The wave form is a square wave having a maximum peak-to-peak voltage when the square wave generator is not loaded to be current limited. Then, sending the positive phase of the wave form to a first loop from a capacitor to the positive side of a battery cell. And, sending the negative phase of the wave form to a second loop from the negative side of the battery cell toward the capacitor. Finally, detecting a change of an electrical signal from the square wave generator. The voltage detection method and apparatus of this invention can be applied to detect whether a rechargeable battery cell has voltage lower than a low voltage limit or to measure the voltage of the battery cell in order to check its status.