Lithium-Ion Battery Internal Resistance

Application ID: 19131

This tutorial digs deeper into the investigation of rate capability in a battery and shows how the Lithium-Ion Battery interface is an excellent modeling tool for doing this.

The rate capability is studied in terms of polarization (voltage loss) or the internal resistance causing this loss. A typical high current pulse test, namely a Hybrid Pulse Power Characterization (HPPC) test, is simulated here for this purpose. Primarily, the first 10 s of discharge and the subsequent relaxation at 298.15 K are investigated.

The Lithium-Ion Battery interface takes into account many physical battery properties of which some can be pinned down as design parameters directly affecting rate capability. These are:

  • thickness of electrodes and separator
  • porosity of electrodes and separator
  • active material particle size
  • choice of active electrode material
  • other material choices, for example, electrolyte and electronic conductor
  • state-of-charge (SOC) of the electrode material; several material properties being SOC dependent
  • Properties that decrease the internal resistance are normally thin battery domains, high porosities, and small active material particles.

    A battery with the opposite design features has high internal resistance, but can instead store a lot capacity (energy) due to large active material particles and thick packed electrodes.

    This model example illustrates applications of this type that would nominally be built using the following products: