ULVAC Develops Integrated Mass Production Technology For Thin-film Lithium Secondary Batteries

January 04, 2009 by Jeff Shepard

ULVAC, Inc. and ULVAC Materials, Inc. announced that they have successfully developed what they describe as the world’s first integrated mass-production technology that enables the manufacture of thin-film lithium secondary batteries.

The thin-film deposition technique is used to produce thin-film lithium secondary batteries. All-solid-state lithium batteries are said to be safer, thinner, lighter and more flexible than liquid-type lithium batteries, and therefore, there is increasing expectation that all-solid-state lithium batteries will be applied to small electronic devices and biomedical devices, such as RF-ID tags and MEMS-IC, and will be combined with energy harvesting devices.

A thin-film lithium secondary battery consists largely of electrode active material layers (cathode and anode), current collector layers, a solid electrolyte layer, and a sealing layer. All the layers can be formed by using a group of ULVAC-developed systems and ULVAC Materials’ targets.

The cathode, solid electrolyte layer and cathode current collector layer are formed using the cluster-type sputtering system (SME-200J), the anode layer is formed by evaporating lithium metal with a vacuum evaporation system (ei-5), and the sealing layer is formed using the cluster-type vacuum evaporation-polymerization system (PME-200).

The sputtering system may be equipped with up to five process chambers such as dc and RF magnetron sputtering chambers, and RTA chambers used for accelerating crystallization. The vacuum evaporation system is equipped with a vapor source and a substrate holder that enable multiple substrate processing to improve the efficiency of batch processing. The evaporation-polymerization system is equipped with a sputtering chamber and evaporation-polymerization chamber that enable the formation of multiple layers of alternating organic and inorganic thin films.

As to sputtering targets, lithium cobalt oxide (LiCoO2) targets have been developed for the cathode, and lithium phosphate (Li3PO4) targets for the solid electrolyte. ULVAC, Inc. and ULVAC Materials, Inc. have jointly developed high-density targets with homogeneous tissue, and have successfully produced a large target with a diameter of 440 mm. The targets will be produced by ULVAC, Inc. and marketed by ULVAC Materials, Inc.