Importance

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Abstract

A long chain battery, particularly for an electric vehicle, comprises a plurality of series connected cells or battery modules. To control the operation of the electrical functions, including discharge while the vehicle is being driven, charging when it is at a charging station, or regenerative charging during braking, a main control module and a plurality of battery monitoring modules are provided. The electric motor and a traction controller therefor are connected in series across the long chain battery, and other vehicle electrical loads are in parallel with the motor and controller. Each battery monitoring module will monitor a number of batteries, and the current carrying wire between them, so that incipient problems may be detected before failure or significant damage occurs. A serial communications bus is provided between the main control module and the battery monitoring modules, and data transmitted over that bus is generally digitally encoded. Sensitive analog circuitry in the battery monitoring modules is located in proximity to the battery modules with which it is associated, and is galvanically isolated from the digital communication circuitry and the data communications bus transmitting the data to the main control module. Any switching or other controllers in the battery are galvanically isolated from the battery monitoring modules and the main control module. Means are provided to isolate specific cells or battery modules, as required; other means are provided to ensure that important voltage and/or current samplings are indicative of equilibrium of the electrical charge or discharge reactions, so that erroneous readings taken during fast acceleration or braking, or other circumstances except essentially steady state conditions, may be discarded. Other means are provided whereby the driver of an electric vehicle receives warnings as the available energy still within the battery depletes below specified levels; and further means are provided to ensure that rate of discharge or regenerative charging of the battery do not exceed predetermined limits.

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First Claim