Battery charge management/protection apparatus

A battery charger/monitor integrated circuit for monitoring and controlling the charging operation of a plurality of series connected battery cells in a battery pack having positive and negative terminals, comprising:

• an integrated circuit package for containing the battery charger/monitor integrated circuit;
• n voltage sense pins integral to said integrated circuit package and adaptable to be connected successively to the terminals of battery cells in a battery pack with the n=1 sense pin connected to the negative terminal of the battery pack and the n sense pin connected to the positive terminal of the battery pack such that adjacent sense pins can be disposed across a given battery cell, wherein a maximum of n-1 battery cells can be accommodated;
• a voltage monitor circuit for monitoring the voltage across adjacent sense pins;
• control pins for outputting charge control signals to an external charge control device;
• a charge control system for controlling the charging operation of the battery pack from an external charging supply in accordance with a charge control scheme that is a function of the monitored voltage of single pairs of said sense pins by generating control signals for output on control pins from the integrated circuit package;
• and
• a blocking circuit for determining if a short is disposed in place of an available cell position whenever less than n-1 cells are present in the battery pack, indicating that no cell is disposed at that cell location, and modifying said function such that the voltage measured across said determined no cell location is not utilized in said function.

A method for charging/monitoring a plurality of series-connected battery cells in a battery pack which can be charged from an external charging supply, comprising the steps of:

• providing a package having a finite set of input/output pins, the input/output pins including a plurality of input sense pins arranged in pairs, each pair able to be connected across the battery cell in a battery pack, wherein each of the cells in the battery pack is associated with a separate one of the pairs of sense pins;
• monitoring the voltage across each of the pairs of sense pins;
• performing a plurality of tests on each pair of sense pins utilizing the associated monitored voltage provided by the step of monitoring, each of the tests operable to determine the characteristics of the battery pack by monitoring the voltage on the sense pins and applying a predetermined test algorithm thereto that compares the determined characteristics with predetermined acceptable limits to determine if the monitored characteristics are outside of the acceptable limits;
• determining if any of the pairs of sense pins has no cell connected thereacross as determined by the monitored voltage output by the step of monitoring;
• controlling the charging and discharging operation of the battery in accordance with the results determined by the test circuit;
• and
• inhibiting the results of the testing steps associated with a given pair of sense terminals determined to have no cell associated therewith from being utilized by the controlling step.