Showa Denko Packaging Co., Ltd. (SPA), a subsidiary of Showa Denko K.K. (SDK), has developed aluminum laminated films with electroconductivity to be used for packaging lithium ion batteries (LIBs) and a new technology to apply these electroconductive laminates to ultra-thin LIBs. These new products and technology are expected to contribute to downsizing and weight reduction of LIBs.
1.Development of tab-leadless LIBs (by giving electroconductivity to laminated films)
Conventional aluminum-laminated-film-based pouch type LIB (laminate LIB) has tab-leads deposited on cathode and anode, through which charge and discharge are conducted. This time, SPA gave electroconductivity to aluminum laminated films by surfacing one side of them with cathodic- or anodic-metal layer, and successfully charged and discharged LIBs through these new type laminates. The new laminates eliminate necessity to deposit tab-leads on cathode and anode, resulting in downsizing and weight reduction of laminate LIBs. Moreover, LIBs pouched with the new laminates eliminate electrolyte leakage from areas around through parts of tab-leads, which is a problem that conventional laminate LIBs have. The new laminates also give more heat radiation capacity to LIBs than conventional ones. Thus the new laminates are expected to be applied to large-sized LIBs including those for car use.
2. Development of ultra-thin LIBs (by integrating electrodes with laminated films)
Furthermore, SPA developed ultra-thin LIBs composed of aluminum laminated films integrated with cathodic/anodic-metal layers and active materials. Ultra-thin LIB is made by applying cathode/anode active materials on the surfaces of the abovementioned new laminates with cathodic/anodic structure, and enclosing electrolyte and separators between these laminated films. By eliminating conventional cathodic/anodic-metal layers, this ultra-thin LIB structure makes it possible to manufacture LIBs and capacitors with thickness of about 100μm, which is less than 50% of conventional ones. Moreover, ultra-thin LIB has improved elasticity and spirality (easy to be curled). Thus ultra-thin LIBs are expected to be applied to slim type products including chip cards, and driving gears.
Compared with metallic LIBs (either cylindrical type or prism type), laminate LIBs, which are pouched in laminated films as composite material of resin films and aluminum foils, provide higher flexibility in molding, lighter weight, and better heat dissipation. The market for aluminum laminated films used for LIB packaging is expected to amount to about \25 billion in 2015, twice the scale of market in 2012. Specifically, demand for small LIBs is growing due to the rise of smart devices such as smartphones and tablets. Demand for large LIBs is also expected to grow due to the progress in the electrification of cars, typically represented by hybrid or electric cars' increasing share.
The Showa Denko Group classifies LIB materials business into the "New Growth" category of its business portfolio specified in the ongoing medium term consolidated business plan "PEGASUS Phase II." Thus, in the market of aluminum laminated films used for LIBs, the Group will work to maintain its leading market share and further improve the product quality, and will aim to ensure stable supply of its products to meet the growing demand for LIBs.
Dr Xiaoxi He, a Technology Analyst at IDTechEx, says "Wearables and portable electronic devices are requiring batteries to have more features such as special form factor, thinness and/or flexibility compared with traditional batteries. Large companies such as Apple, LG and Samsung have put their effort in developing their own thin and flexible batteries. Many other international players are targeting this market as well. We find that thin and flexible energy storage devices will create a market in excess of $400 million in 2025." For more details, please refer to IDTechEx's new report: "Flexible, Printed and Thin Film Batteries 2015-2025: Technologies, Forecasts, Players".
Source and top image: Showa Denko