| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a secondary battery, capable of enhancing advantage of electric power charge reduction, when liberalization of power retail is real ized. <P>SOLUTION: In the using method of a secondary battery, electric power can be selectively received from a plurality of power supply companies. A secondary battery is charged (S16) by electric power received for the selected power supply company (S2). By using electric power (S10) discharged from the secondary battery, the charge of the received electric power is paid to the selected power supply company. By using the data of respective electric power charges obtained from the plurality of power supply companies (S2), the power supply company offering the lowest electric power rate is selected to receive electricity (S4). When the electric power charge of the selected power supply company is larger than the prescribed first electric power rate (S6), the secondary battery is discharged (S10). When the electric power charge is not larger than the second electric power rate, which is lower than the first electric power rate (S12), the secondary battery is charged by the received electric power (S16). <P>COPYRIGHT: (C)2004,JPO |
