System and method for measuring series-connected cell voltages using a flying capacitor with self calibration

A system for measuring voltage of individual cells in a plurality of cells connected in series, the system comprising:

• a capacitor having terminals;
• at least one switch electrically connected to the capacitor;
• an amplifier having inputs and an output, the inputs electrically connected to the terminals of the capacitor;
• an analog-to-digital converter (ADC) electrically connected to the output of the amplifier;
• and
• at least one precision voltage reference (PVR) device electrically connectable to the ADC.

A system for measuring voltage of individual cells in a plurality of cells connected in series, the system comprising:

• a capacitor having terminals;
• at least one switch electrically connected to the capacitor;
• an amplifier having inputs and an output, the inputs electrically connected to the terminals of the capacitor;
• an analog-to-digital converter (ADC) electrically connected to the output of the amplifier;
• at least one precision voltage reference (PVR) device electrically connectable to the ADC;
• and
• a multiplexer having a first multiplexer input, a second multiplexer input, and a multiplexer output electrically connected either of said first multiplexer input or said second multiplexer input to said multiplexer output, wherein said first multiplexer input is electrically connected to said amplifier, said second multiplexer input is electrically connected to said PVR device, and said multiplexer output is electrically connected to said ADC.

A system for measuring voltage of individual cells in a plurality of cells connected in series, the system comprising:

• a capacitor having terminals;
• at least one switch electrically connected to the capacitor;
• an amplifier having inputs and an output, the inputs electrically connected to the terminals of the capacitor;
• an analog-to-digital converter (ADC) electrically connected to the output of the amplifier;
• at least one precision voltage reference (PVR) device electrically connectable to the ADC;
• a plurality of cell switches for electrical connection to a plurality of cells, wherein each cell switch includes a first side and a second side, wherein said first side of each cell switch electrically connectable to a positive terminal of one of the cells;
• a first bus electrically connected to said second side of alternate cell switches;
• and
• a second bus electrically connected to said second side of each cell switch not connected to said first bus.

A method for measuring voltage of individual cells in a plurality of cells connected in series, the method comprising the steps of:

• charging a capacitor electrically connected to at least one cell for a first charge duration;
• obtaining a charge voltage reading from the capacitor;
• discharging the capacitor for a first discharge duration;
• obtaining a discharge voltage reading from the capacitor;
• and
• signaling a malfunction if the discharge voltage reading is greater than a predetermined voltage level.