  The two-band Hubbard model is used to analyze a possibility of a non-uniform
charge distribution in a strongly correlated electron system with two types of
charge carriers. It is demonstrated that in the limit of strong on-site Coulomb
repulsion, such a system has a tendency to phase separation into the regions
with different charge densities even in the absence of magnetic or any other
ordering. This tendency is especially pronounced if the ratio of the bandwidths
is large enough. The characteristic size of inhomogeneities is estimated
accounting for the surface energy and the electrostatic energy related to the
charge imbalance.
