Electrochemical engineering is the branch of chemical engineering dealing with the technological applications of electrochemical phenomena, such as electrosynthesis of chemicals, electrowinning and refining of metals,  flow batteries and fuel cells, surface modification by electrodeposition, electrochemical separations and corrosion.
According to the IUPAC, the term electrochemical engineering is reserved for electricity-intensive processes for industrial or energy storage applications and should not be confused with applied electrochemistry, which comprises small batteries, amperometric sensors, microfluidic devices, microelectrodes, solid-state devices, voltammetry at disc electrodes, etc.
More than 6% of the electricity is consumed by large-scale electrochemical operations in the US.