MAKING LITHIUM SECONDARY BATTERY ELECTRODES USING AN ATMOSPHERIC PLASMA

摘要

The manufacture of electrode members for lithium-ion electrochemical cells and batteries is more efficient using an atmospheric plasma stream in carrying, heating, and directing current collector and electrode materials for deposition on thin sheet substrates. Particles of conductive metals are heated and partially melted in the plasma and deposited as current collector films for active electrodes (and reference electrodes) at relatively low temperatures (<100° C.) on separator sheets. Particles of lithium-ion accepting and releasing electrode materials are combined with smaller portions of conductive metals for plasma heating and deposition on current collector layers in forming positive and negative electrodes for lithium-ion cells. Such use of the atmospheric plasma avoids the need for the use of organic binders and wet deposition practices in electrode layer manufacture, and enables the deposition of thicker, lower stress layers of active electrode materials for higher cell capacity and power.

主权项

1. A method of forming an electrode member of a lithium-ion electrochemical cell, the formed electrode member comprising at least two bonded sheet layers, the method comprising:
adding solid particles of lithium-ion cell electrode material to a flowing gas stream, the solid particles consisting essentially of (i) particles of an electrically conductive metal or of (ii) particles of a lithium-ion cell electrode material combined with an amount of electrically conductive metal for bonding of the particles of electrode material, the solid particles being dispersed and carried in the flowing gas stream; generating an atmospheric plasma in the gas stream to heat the solid particles by the plasma and to at least partially melt the electrically conductive metal; and directing the atmospheric plasma, containing the heated solid particles, against a selected surface of a substrate, while moving at least one of the directed plasma and the selected surface of the substrate with respect to the other, to deposit the plasma-heated solid particles in a sheet layer of predetermined thickness and porosity on the selected surface area of the substrate, the conductive metal re-solidifying to bond the solid particles to each other in the sheet layer and to bond the sheet layer to the substrate; the substrate being a sheet layer portion of an electrode member of a lithium-ion electrochemical cell or a separator membrane member of a lithium-ion electrochemical cell, the final sheet thickness of deposited plasma-heated solid particles on the selected area of the substrate being up to about two hundred micrometers and comprising one or more sheet layers of such deposited plasma-heated solid particles.