The invention discloses a battery internal
short circuit detection method and device which are applied to a
battery pack comprising a plurality of single batteries, and the method comprises the steps: obtaining the current information of the
battery pack and the
voltage information of each single battery; constructing observed quantity representing
monomer difference, and estimating a first difference parameter representing
monomer voltage source characteristic difference and a second difference parameter representing
monomer impedance characteristic difference on line by adopting
nonlinear filtering to obtain a corresponding
time sequence; segmenting the
time sequence according to a preset operation period, and performing weighted convergence according to weights related to electric quantity changes to obtain corresponding characteristic parameters; and constructing a first statistical discrimination quantity and a second statistical discrimination quantity which reflect extreme value deviation and fluctuation deviation based on the periodic characteristic parameters, performing joint discrimination with a threshold value, and determining an internal
short circuit when abnormal monomers are consistent and meet a continuous periodic criterion. According to the method, through difference observation, filtering
estimation, periodic weighting and double-
discriminant-quantity combined judgment, the
discriminant stability and reliability under working condition fluctuation and
noise interference are improved.