Amongst all the modifications of the PS Complex to produce the LHC ion beams, the conversion of the old Low-Energy Antiproton Ring into the Low-Energy Ion Ring (LEIR) is a major issue. The accumulation in LEIR of 9×108 lead ions in normalized transverse emittances of 0.7 μm allows the production of 4 of the 592 bunches needed in one LHC ring, in one LEIR cycle. Then, it will take around 10 min to fill one LHC ring. The requested luminosity of 1027 cm-2 s-1 for lead ion collisions is reachable and is ∼1000 times more that the actual chain (Linac3, PSB) can do. The production of lead ion beams is described, with particular attention to the cooling, the injection system and the beam lifetime.