A fundamentally new approach to battery performance analysis using DFRA/sup TM//DPIS/sup TM/ technology

Digital Frequency Response Analysis (DFRA/sup TM/) combined with Discrete Frequency Immittance Spectroscopy (DFIS/sup TM/) provides an important new technique for evaluating battery performance parameters. The cell/battery is excited with a periodic current, and its complex impedance Z (or admittance Y) is determined at the excitation's fundamental frequency using DFRA/sup TM/ By measuring complex Z (or Y) at n discrete frequencies, and combining the 2n measured quantities using DFIS/sup TM/, the technique evaluates elements of a unique 2n-element equivalent circuit model of the cell/battery. The 2n element values contain virtually the same information as the continuous Z (or Y) spectrum expressed over a wide frequency range. In addition, the elements themselves represent actual physical and/or electrochemical processes occurring within the cell/battery. Accordingly, their values yield potentially useful new information concerning cell/battery performance.