An electrochemical cell assembly (1400) comprising a base plate (308) and a top plate (303) between which a stack of planar cell units (306) and at least one electrical end plate (1402, 1407) are disposed in compression. The electrical end plate (1402, 1407) comprises a two-layer construction in which a first layer (1416, 1419) and a second layer (1417, 1420) formed of different respective materials are permanently connected together to form a single conductive body. The first layer (1416, 1419) of the electrical end plate (1402, 1407) is electrically connected to an external electrical terminal (301, 505) of the cell assembly, and the second layer (1417, 1420) of the electrical end plate (1402, 1407) has an outwardly facing side having a first electrically conductive ceramic layer (1418, 1824) bonded thereto that is in face-to-face abutment with, and in electrical contact with, an adjacent cell unit (306).