Patent ID: 7399321

Claim:
A method of reflow soldering a non-aqueous electrolyte secondary battery comprised of a non-aqueous electrolyte and a cathode having an active material containing lithium ions, comprising the steps of: discharging the non-aqueous electrolyte secondary battery to a first discharge voltage different from a second discharge voltage at an inflection point in a discharge curve of the non-aqueous electrolyte secondary battery having an axis of abscissa representing discharge capacity and an axis of ordinate representing discharge voltage; placing the discharged non-aqueous electrolyte secondary battery on a substrate; and exposing the substrate to a reflow soldering temperature to reflow solder the non-aqueous secondary battery to the substrate; wherein the first discharge voltage is higher than the second discharge voltage to prevent degradation of characteristics of the non-aqueous electrolyte secondary battery resulting from decomposition of the non-aqueous electrolyte due to reaction of the non-aqueous electrolyte with excessive lithium ions in the cathode active material when the non-aqueous electrolyte secondary battery is exposed to the reflow soldering temperature.