400-Ah lithium-ion cells for telecommunications systems and DC power supply systems

To expand the application of lithium-ion batteries in back-up power supplies for telecommunications equipment, we manufactured large-capacity 200-Ah and 400-Ah lithium-ion cells and measured their characteristics. We also propose a lithium-ion battery management system that charges cells individually to replace the conventional system in which a cell voltage equalizing circuit is installed in parallel with the cells. We constructed a mock DC power supply system for telecommunications equipment that has a nominal output voltage of -48-V and applied this method to a 12-cell in-series battery pack to measure the power supply system characteristics. Here, we report the basic characteristics of the 200-Ah large-capacity lithium-ion cells and the characteristics of a DC power supply system that uses a battery pack equipped with this management and control system.