Abstract: A power storage system that includes a first power storage pack and a second power storage pack. The second power storage pack is connected in parallel to the first power storage pack. The charge/discharge curve for the second power storage pack has a step passing through the open-circuit voltage of the first power storage pack at a SOC of 50%. The average discharge voltage on the lower SOC side of the start point of the step of the charge/discharge curve for the second power storage pack is ?25% or more of the open-circuit voltage of the first power storage pack at a SOC of 50%. The average charge voltage on the higher SOC side of the end point of the step of the charge/discharge curve for the second power storage pack is +25% or less of the open-circuit voltage of the first power storage pack at a SOC of 50%.

Abstract: A power storage pack having a charge/discharge curve with a step passing through the range of (12.5×n) V to (12.8×n) V, where n is a natural number of 1 to 125. The average discharge voltage on the lower SOC side of the start point of the step of the charge/discharge curve for the power storage pack fails within the range of (9.0×n) V to (12.5×n) V. The average charge voltage on the higher SOC side of the end point of the step of the charge/discharge curve for the power storage pack falls within the range of (12.8×n) V to (14.8×n) V.

Abstract: A power supplying system that includes a power supplying mechanism, an electric load, a power line, and a storage pack. The power supplying mechanism supplies a DC power. The electric load is connected to the power supplying mechanism by the power line. The storage pack is connected to the power line. The charging/discharging curve of the storage pack has a step difference that passes through the rated voltage of the power supplying mechanism. An average discharging voltage on a lower-SOC side of the start point of the step difference is ?20% or more of the rated voltage. An average charging voltage on a higher-SOC side of the end point of the step difference is +20% or less of the rated voltage.

Abstract: A first cell string provided in a first battery module has a larger allowable current value than a plurality of cell strings provided in second and third battery modules. The battery module is provided with a current limiting circuit that limits the charge and discharge currents of the second cell string. When the current value detected by a current sensor is zero, the switch is turned off. In this condition, when the terminal voltage value of the third cell string is different from the terminal voltage value of the second cell string, a second switch switches the connection between the second and third battery modules in order to interpose the current limiting circuit between the second and third cell strings.

Abstract: A power storage system that includes a first power storage pack and a second power storage pack. The second power storage pack is connected in parallel to the first power storage pack. The charge/discharge curve for the second power storage pack has a step passing through the open-circuit voltage of the first power storage pack at a SOC of 50%. The average discharge voltage on the lower SOC side of the start point of the step of the charge/discharge curve for the second power storage pack is ?25% or more of the open-circuit voltage of the first power storage pack at a SOC of 50%. The average charge voltage on the higher SOC side of the end point of the step of the charge/discharge curve for the second power storage pack is +25% or less of the open-circuit voltage of the first power storage pack at a SOC of 50%.

Abstract: A power supplying system that includes a power supplying mechanism, an electric load, a power line, and a storage pack. The power supplying mechanism supplies a DC power. The electric load is connected to the power supplying mechanism by the power line. The storage pack is connected to the power line. The charging/discharging curve of the storage pack has a step difference that passes through the rated voltage of the power supplying mechanism. An average discharging voltage on a lower-SOC side of the start point of the step difference is ?20% or more of the rated voltage. An average charging voltage on a higher-SOC side of the end point of the step difference is +20% or less of the rated voltage.

Abstract: A power storage pack having a charge/discharge curve with a step passing through the range of (12.5×n) V to (12.8×n) V, where ii is a natural number of 1 to 125. The average discharge voltage on the lower SOC side of the start point of the step of the charge/discharge curve for the power storage pack fails within the range of (9.0×n) V to (12.5×n) V. The average charge voltage on the higher SOC side of the end point of the step of the charge/discharge curve for the power storage pack falls within the range of (12.8×n) V to (14.8×n) V.

Abstract: A first cell string provided in a first battery module has a larger allowable current value than a plurality of cell strings provided in second and third battery modules. The battery module is provided with a current limiting circuit that limits the charge and discharge currents of the second cell string. When the current value detected by a current sensor is zero, the switch is turned off. In this condition, when the terminal voltage value of the third cell string is different from the terminal voltage value of the second cell string, a second switch switches the connection between the second and third battery modules in order to interpose the current limiting circuit between the second and third cell strings.