Collision of laser-driven subrelativistic high-density ion flows provides a way to create extremely compressed ion conglomerates and study their properties. This paper presents a theoretical study of the electrodynamic implosion of ions inside a hollow spherical or cylindrical shell irradiated by femtosecond petawatt laser pulses. We propose to apply a very effective mechanism for ion acceleration in a self-consistent field with strong charge separation, based on the oscillation of laser-accelerated fast electrons in this field near the thin shell. Fast electrons are generated on the outer side of the shell under irradiation by the intense laser pulses. It is shown that ions, in particular protons, may be accelerated at the implosion stage to energies of tens and hundreds of MeV when a sub-micrometer shell is irradiated by femtosecond laser pulses with an intensity of 10²¹–10²³ W cm^-2.