Patent ID: 8183832

Claim:
A charging system, comprising: a nonaqueous electrolyte secondary battery; a charge current feed portion that feeds a charge current to the nonaqueous electrolyte secondary battery; a voltage detection portion that detects a terminal voltage across the nonaqueous electrolyte secondary battery; a first charge control portion that performs initial current set processing by which the charge current feed portion is controlled to feed, as a feed amount of the charge current by the charge current feed portion, the charge current at a first current value exceeding a reference current value preset as a current value of the charge current at which the charge current is flown without causing any deterioration in the nonaqueous electrolyte secondary battery while negative electrode potential of the nonaqueous electrolyte secondary battery is substantially 0 V; and a second charge control portion that causes, after the initial current set processing is performed by the first charge control portion, the feed amount of the charge current by the charge current feed portion to change so that the current value decreases as the terminal voltage detected by the voltage detection portion increases until the terminal voltage detected by the voltage detection portion reaches an end voltage, which is the terminal voltage across the nonaqueous electrolyte secondary battery when the negative electrode potential of the nonaqueous electrolyte secondary battery is substantially 0 V.