摘要 |
The problem of the present invention is to provide a sodium ion battery system with high charge and discharge efficiency. The present invention solves the above-mentioned problem by providing a sodium ion battery system comprising a sodium ion battery and a charge control unit, wherein the anode active material is an active material having an Na2Ti6O13 crystal phase, the anode active material layer contains a carbon material as a conductive material, and the above-mentioned charge control unit controls electric potential of the above-mentioned anode active material higher than electric potential in which an Na ion is irreversibly inserted into the above-mentioned carbon material. |