Electrode plate of an electrochemical battery and electrochemical battery comprising such electrode plate

An electrode plate of an electrochemical battery, the electrode plate comprising a frame and a generally flat grid connected to the frame, the frame comprising at least a top frame member having a contact lug, wherein the grid comprises a plurality of grid wires arranged in a pattern and a plurality of window-like open areas between the grid wires, further comprising an active mass within the open areas and/or on the grid wires, wherein the electrode plate comprises on one outer surface or on both opposing outer surfaces of the active mass a pattern of grooves, wherein the grooves extend diagonally from a position closer to the top frame member to a position further away from the top frame member, wherein the pattern of grooves comprises a first group of diagonally extending grooves and a second group of diagonally extending grooves, wherein the grooves of the first group of grooves intersect with the grooves of the second group of grooves, wherein the pattern of grooves forms a plurality of crossing points between the grooves of the first group of grooves and the grooves of the second group of grooves, wherein a two-dimensional arrangement of the pattern of the grid wires differs from a two-dimensional arrangement of the pattern of grooves when looking on the one outer surface of the active mass of the electrode plate where the pattern of grooves is formed, and wherein the pattern of the grid wires is only partially covered by the pattern of grooves.