M.S. Yu, M.Y. Song, M.H. Kim, H.A. Lee, D.S. Kim
Keywords: roll to roll, gravure coater, pouch film, lithium polymer battery
Summary:Lithium ion secondary battery is used in various industries such as mobile/IT devices, Electric vehicles and Energy storage system. Among them, the lithium polymer battery is more safety than the existing battery. The use of a polymer electrolyte makes it possible to reduce the possibility of explosion, and as a pouch type battery, it can be made lighter and thinner. The application of lithium polymer battery to electric vehicle is increasing due to high design freedom and light weight. Also, the demand for electric vehicles is increasing because eco-friendly technology becomes more important. Therefore the demand for lithium polymer battery is increasing. The pouch film is packaging material for lithium polymer battery and it is a composite film. This film composed of a metal and polymer films. Each film is laminated via polyurethane or polyolefin based adhesive. We apply to Roll to Roll dry lamination using gravure coater by manufacturing equipment. This technology can be a simple and continuous process. Also, the gravure coater is capable of uniform coating, which improves coating quality and yield. The pouch film have a stable adhesive strength between the metal (Aluminum foil) and polymer film (CPP : Casted Polypropylene). In this paper, we founded optimal process conditions for electric vehicle battery with stable properties. A dry temperature of surface treatment agent of 100℃, an adhesive dry temperature of 80℃, lamination temperature of 110℃ and lamination pressure of 100kgf/cm2 were applied at a speed of 18m/min. As a result, we manufactured a pouch film having a stable adhesive strength of 11.8N/15mm. The commercialization of adhesive strength is 10N/15mm or more.