The invention relates to a preparation method of a 
lithium-
copper composite negative 
electrode foil piece. An intermittent 
local pressure enhancement method is adopted for uniformly adhering 
lithium metal foil pieces on the surface of a 
copper foil, and a 
lithium-
copper composite negative 
electrode foil piece is formed. The preparation method comprises the following concrete steps: clamping the 
copper foil between the 
lithium metal foil pieces to form a lithium foil / 
copper foil / lithium foil sandwich layer; adopting common rolling equipment, starting a 
traction system, and enabling the lithiumfoil / 
copper foil / lithium foil sandwich layer to pass through a 
grinding roller, so as to form intermittent 
local pressure on the lithium foil / copper foil / lithium foil sandwich layer, wherein the 
pressure range is 0.05-5MPa, and a pre-compounded lithium foil / copper foil / lithium foil sandwich slice is formed; and enabling the pre-compounded lithium foil / copper foil / lithium foil sandwich slice to pass through the 
grinding roller again, and applying pressure for shaping, wherein the 
pressure range is 0.02-5MPa, so that the lithium-copper composite negative 
electrode foil piece is obtained. The preparation method provided by the invention has the beneficial effects that layer-to-layer contact of the prepared lithium-copper composite negative electrode foil piece is uniform, contact of a lithiummetal negative electrode with the copper foil is further improved, and the problem that the 
lithium metal foil piece and the copper foil are infirmly bonded is avoided, so that outage of 
lithium metal in a working process of a battery is prevented.