Battery system

A battery system comprising:

• a battery including:
• a first power storage unit;
• a second power storage unit;
• and
• a switch configured to switch between a first voltage state in which the first power storage unit and the second power storage unit are connected in series and are chargeable at a first voltage, and a second voltage state in which the first power storage unit and the second power storage unit are connected in parallel and are chargeable at a second voltage;
• and
• a switch drive mechanism configured to drive the switch, wherein
• the switch includes:
• a first switch configured to be turned on when the battery is in the first voltage state, and turned off when the battery is in the second voltage state;
• and
• a second switch configured to be turned on when the battery is in the second voltage state, and turned off when the battery is in the first voltage state,
• the switch drive mechanism includes a power supply for driving the switch, and a switch drive circuit,
• the switch drive circuit connects the power supply and a positive electrode of the first switch, connects a negative electrode of the first switch and a negative electrode of the second switch, and connects a positive electrode of the second switch and the power supply, and
• the switch drive mechanism
• when the battery is in the first voltage state, supplies the first switch with a current in a forward direction to turn on the first switch, and supplies the second switch with a current in a reverse direction to turn off the second switch, and
• when the battery is in the second voltage state, supplies the second switch with a current in the forward direction to turn on the second switch, and supplies the first switch with a current in the reverse direction to turn off the first switch.