Battery and power storage system

A battery, comprising:

• a first power storage;
• a second power storage;
• a positive node configured to connect in parallel a positive terminal of the first power storage and a positive terminal of the second power storage;
• a negative node configured to connect in parallel a negative terminal of the first power storage and a negative terminal of the second power storage;
• one of a main contactor and a control cutoff fuse configured to cut off according to a control signal, the one being provided at a side opposite to the first power storage and the second power storage with respect to the positive node;
• an other one of the main contactor and the control cutoff fuse, the other one being provided at a side opposite to the first power storage and the second power storage with respect to the negative node;
• a connection circuit configured to connect the negative terminal of the first power storage and the positive terminal of the second power storage;
• a first switching contactor provided in the connection circuit;
• a second switching contactor provided between the positive node and a first connection portion configured to connect the positive terminal of the second power storage and the connection circuit;
• a third switching contactor provided between the negative node and a second connection portion configured to connect the negative terminal of the first power storage and the connection circuit;
• and
• a controller configured to control on and off of the main contactor and the first to third switching contactors,
• wherein the controller is configured to switch between
• a first voltage state in which the first switching contactor is in an on state, the second switching contactor and the third switching contactor are in an off state, and the first power storage and the second power storage are connected in series and chargeable at a first voltage, and
• a second voltage state in which the first switching contactor is in an off state, the second switching contactor and the third switching contactor are in an on state, and the first power storage and the second power storage are connected in parallel and chargeable at a second voltage.