To provide a battery pack which can cope with either of normal charging and high speed charging, and which has a high precision charging control in the high speed charging, and which has superior charging efficiency.

In the battery pack provided with a chargeable battery and a protection circuit against an excessive current to the battery, a charging and discharging passage in which normal charging is possible and a charging current passage in which high speed charging is possible are installed at the battery, and a voltage detection passage different from the charging current passage in which high speed charging is possible is installed, so that the voltage detection of the battery is enabled by using the voltage detection passage.

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