Apparatus and method for diagnosing abnormality in cell balancing circuit

摘要

Disclosed is an apparatus and method for diagnosing an abnormality in a cell balancing circuit in a battery pack including a plurality of cells corresponding to each cell balancing circuit. The present disclosure turns off cell balancing switches included in a cell balancing circuit to be diagnosed and an adjacent cell balancing circuit among the cell balancing circuits. Also, the present disclosure stores a voltage value between nodes of the cell (hereinafter referred to as a ‘diagnosis voltage value’) by turning on the cell balancing switch of the cell balancing circuit to be diagnosed. Also, the present disclosure calculates a difference value between adjacent cell voltage values (hereinafter referred to as a ‘cell difference value’) and a difference value between adjacent diagnosis voltage values (hereinafter referred to as a ‘diagnosis difference value’).

主权项

1. An apparatus for diagnosing an abnormality in a cell balancing circuit in a battery pack including a plurality of cells corresponding to each cell balancing circuit, the apparatus comprising:
a cell balancing circuit connected in parallel to a voltage sensing line connected to both terminals of each cell, and including a cell balancing switch and a discharge resistor; a diagnosis resistor installed on the voltage sensing line at the side of the cell with respect to a node (a high potential node and a low potential node) at which the cell balancing circuit and the cell voltage sensing line are connected; a voltage sensing circuit to output a voltage corresponding to a voltage difference between the high potential node and the low potential node (hereinafter referred to as an ‘inter-node voltage value); and a control unit to store an inter-node voltage value (hereinafter referred to as a cell voltage value) in a turn-off state of the cell balancing switches and an inter-node voltage value (hereinafter referred to as a diagnosis voltage value) by turning on a cell balancing switch of a cell balancing circuit to be diagnosed among the cell balancing circuits in a turn-off state of a cell balancing switch included in a cell balancing circuit adjacent to the cell balancing circuit to be diagnosed, to calculate a difference value between adjacent cell voltage values (hereinafter referred to as a cell difference value) and a difference value between adjacent diagnosis voltage values (hereinafter referred to as a diagnosis difference value), and to determine whether an abnormality is present in the cell balancing circuit by analyzing a change pattern of a difference value between the cell difference value and the diagnosis difference value (hereinafter referred to as a determination value).