Fundamental characteristics of stationary lithium-ion secondary cells and a cell-voltage-management system

Residual capacity estimation of stationary lithium‐ion secondary battery based on its discharge voltage characteristics

“…However, considering the applications in the system, it is important to be able to easily calculate the voltage drop by measuring the voltages before commencing the test and during the test; therefore, an index derived from larger measured values, which reduces errors, is preferable. Thus, item (3), that is, the discharge voltage drop from the charge voltage, was selected, and the relationship between this index and the residual capacity was determined for each single cell and the multicell battery. Figure 6 shows the change in residual capacity of the samples in the high-temperature accelerated tests.…”

“…Targeting applications in telecommunications power supply systems, I examined the basic characteristics of high-capacity Li-ion secondary cells and, based on the results, proposed and described the advantages of a single-cell voltage adjusting circuit required in multicell batteries for application to telecommunications power systems [3]. A prototype rack-mounted DC power supply including such a Li-ion battery was also constructed, and its characteristics were reported [4].…”

Field trial on a rack‐mounted DC power supply system with 80‐Ah lithium‐ion batteries

“…In the case of lithium-ion cells, the accumulated charge is proportional to the charge voltage, and therefore, at a constant temperature, the difference in voltage is equal to the difference in capacity [7]. As regards the daily variations shown in Fig.…”

Deterioration estimation of lithium-ion cells in direct current power supply systems and characteristics of 400-Ah lithium-ion cells

“…Largecapacity Li-ion cells with high energy density characteristics have been developed, and pre-production has progressed on industrial Li-ion cells that have sufficient capacity to serve as backup power supplies for telecommunications equipment [1]. Considering the background of these technical developments, we evaluated various characteristics of industrial Li-ion cells to clarify if they have adequate performance for use as backup batteries in telecommunications power supply systems and to identify the battery management functions that are required to keep the cell characteristics stable for long periods in such applications [2]. In backup batteries for telecommunications equipment, the cells need to be kept fully charged, and if possible, an automated system for doing so should be incorporated into the power supply system.…”