The paper is related to a study that analyzes the effects of fast charge on a lithium-ion storage system at its
different architectural levels: cell, battery module, complete battery system. A first set of tests was executed
on a lithium-iron-phosphate cell subjected to a test profile which simulates the real working profile
requested to the batteries to perform a particular service of local public transportation. This test profile
includes a fast charge step at current rate 3C. More than 2000 cycles were executed and the cell did not
show a significant reduction of performances. This encouraging result suggested to move up a grade in the

architectural level, so a second set of tests was executed on a battery module made by 4 lithium-iron-
phosphate cells series connected, submitted to the aforesaid test profile conveniently adapted to module

level: before succeeding to perform the test profile, it was necessary to overcome different problems mainly
due to the unbalancing of the cells which is particularly emphasized by the fast charge. These problems are
typical of the battery packs, where more cells are connected together. The battery and thermal management
systems housed inside the module made possible an optimization of the performances: more than 1600
cycles were executed with good results and the test is still in progress till to reach the end of life condition.
The final grade of the experiment will be the test of 24 modules connected together to build a complete
battery system installed on board a real minibus working according the mission above defined. The
description of the problems encountered and test results related in the paper tries to give a good information
about the impact on the performances and life of a storage system submitted to fast charge.