Impedance balancing and continuity assurance for current limiting element in parallel path for prevention of thermal runaway propagation in battery system, packs and modules

A method for testing a battery module comprising:

• applying a test signal to one end of a passive current limiting element associated with a corresponding group of cells of a plurality of groups of cells mounted within a battery module housing, each group of cells comprising a plurality of parallel connected cells from among the plurality of cells, where the plurality of groups of cells is connected in series, each corresponding group of cells having a corresponding plurality of current limiting elements, each current limiting element being electrically connected in a parallel path to one or both terminals of cells which are parallelly connected, the passive current limiting element connected in parallel to a plurality of electrically connected current limiting elements in the parallel path, the test signal for testing the parallel plurality of current limiting elements electrically connected in the parallel path;
• and sensing, using a sensing circuit connected to the terminal of a first current limiting element, a signal flowing through the plurality of electrically connected current limiting elements in the parallel path responsive to the applied test signal, said signal indicating blown one or more of:
• a blown current limiting element or a broken connection in said parallel path.