DC backup power supply system

A DC backup power supply system comprising:

• a battery;
• a charge-discharge circuit for charging and discharging a power between said battery and a DC line;
• and
• a control circuit for controlling said charge-discharge circuit,
• wherein said battery has a number of battery cells, cylindrical portions of the battery cells are laid on an approximately horizontal plane, and a height of said battery is 45 mm or lower.

A DC backup power supply system comprising:

• a battery;
• a charge-discharge circuit for charging and discharging a power between said battery and a DC line;
• and
• a control circuit for controlling said charge-discharge circuit,
• wherein said battery has a number of battery cells, cylindrical portions of the battery cells are laid on an approximately horizontal plane, and said battery is accommodated in a space having a height corresponding to one unit (1U) size of a 19-inch rack.

A DC backup power supply system comprising:

• a battery;
• a charge-discharge circuit for charging and discharging a power between said battery and a DC line;
• and
• a control circuit for controlling said charge-discharge circuit,
• wherein said battery has a number of battery cells, cylindrical portions of the battery cells are laid on an approximately horizontal plane, a plurality of DC backup power supply systems electrically connected in parallel are accommodated and juxtaposed in one rack, and the DC backup power supply systems have electric hot swap connections using connectors and cables.