  The Large Hadron Electron Collider (LHeC) project is the proposal to use the
existing LHC proton/ion beams and construct a new electron beam line to perform
high-energy electron-proton/ion collisions. In this talk, we consider some of
the physics topics that could be studied in the electron-ion mode. In
particular, we estimate how much the current nuclear parton distribution fits
could be improved with the deeply inelastic scattering measurements at the LHeC
by including pseudodata into a global analysis. In addition, we discuss briefly
other topics that would help to better understand some aspects of heavy-ion
collisions, namely small-$x$ physics and hadron production with a nuclear
target.
