Method of using cyclic pressure to increase the pressed density of electrodes for use in electrochemical cells

Abstract

The traditional method of building a CF/current collector/SVO assembly is by the application of a static pressing force. However, the density of the electrode and, particularly the CFcomponent, can be increase by using a cyclic pressing protocol. That is where the active materials are formed into a blank or contacted to a current collector by the use of at least two pressing events separated by a period when the pressure is removed. Not only does this cyclic pressing protocol increase the density of the CFmaterial, it also provides an electrode that is relatively flat, and not cupped. Conventional pressing techniques often result in badly cupped electrodes, especially when disparate active materials are contacting opposite sides of the current collector. Cupping consequently reduces the effective volumetric energy density of the electrode or necessitates the addition of a process step of flattening of the cathode, if at all possible. According to the new cyclic pressing protocol, the physical density of the cathode is increased and electrode cupping is effectively eliminated.