The negative and positive electrodes 22, 24 are generally associated with the respective negative and positive electrode current collectors 32, 34 to facilitate the flow of electrons between the electrode and the external circuit 40. The current collectors 32, 34 are electrically conductive and can include metal, such as a metal foil, a metal grid or screen, or expanded metal. Expanded metal current collectors refer to metal grids with a greater thickness such that a greater amount of electrode material is placed within the metal grid. By way of non-limiting example, electrically-conductive materials include copper, nickel, aluminum, stainless steel, titanium, alloys thereof, or combinations thereof.
The positive electrode current collector 34 may be formed from aluminum or any other appropriate electrically conductive material known to those of skill in the art. The negative electrode current collector 32 may be formed from copper or any other appropriate electrically conductive material known to those of skill in the art. Negative electrode current collectors do not typically include aluminum because aluminum reacts with lithium, thereby causing large volume expansion and contraction. The drastic volume changes may lead to fracture and/or pulverization of the current collector.