Transition to thin-film batteries based on automated manufacturing technologies
Tsung-Yeh Yang, Ph.D., manager, sales department, energy development factory, Toes Opto-Mechatronics, pointed out the thin-film battery is a type of lithium battery and is generally made by CVD deposition of anode and cathode materials which are then assembled into a battery cell as thin as a few microns. However, the process is complicated and the equipment is costly, so production in mass quantities is not easily achieved and thus poses a challenge to end product applications.
In light of this, Toes decided to move away from traditional sputtering and evaporation processes. Instead, Toes uses manganese dioxide (positive electrode) and lithium metal (negative electrode) to form colloidal electrolyte with high polymer so that the battery resembles a liquid battery but better adapts to extreme high or low temperature environments without safety concern such as leakage. Complemented with Toes' development and manufacture capabilities of high precision assembly equipment, mass production at accelerated speed is made feasible.
Toes' core technologies in flexible thin-film batteries originate from two major aspects. One is the bonding technology that sets itself part from traditional roll bonding or stacking and simulates the concept of gluing sheets of paper together so that the cell electrode modules are close-packed. The other is surface modification of current collectors that ingeniously eliminates corrugation resulted from bending common metal materials.
Yang indicated bonding and surface modification are exactly the processes critical to the thinness and flexibility features of thin-film cells. Three unique advantages come from these processes – current collectors formed of active materials, self-designed bonding equipment, and colloidal electrolyte uncommon in the industry. These technological advantages have given rise to the safety, ultra-thinness, flexibility, and high capacity features of Toes' thin-film batteries.
Portable electronic products are booming and applications adopting thin-film batteries are widespread, including Easy Cards used to pay transportation fares, identifiers for safety control, transmitters for wireless communication, smart cards for banking transactions, electronic purses, and even cosmetic or medicated patches. As such, Toes will undoubtedly focus on these smart applications surrounding portable electronics as its top priority.
However, looking forward to the future, the ideal stage for flexible thin-film batteries will be wearable devices with explosive opportunities. As known to all, since 2013 Google has launched Google Glass and industry leaders such as SONY as well as Samsung have marketed smart watches, which has set off a trend of wearable devices followed by applications in multiple fields including information, entertainment, exercise, fitness, medical care, manufacturing, and military, all full of great development potential. However, these products, whether smart wrist bands or smart watches, all face the problems of insufficient battery life and battery installation compromising product design aesthetics. Flexible and high-capacity watch strap batteries are the answer to these problems, which open up massive opportunities for Toes' thin-film batteries.
Liang said Toes will be able to produce flexible batteries in mass quantities in 2015 and will initially target powered smart card technologies. Marketing focus will be on sheet or stick secondary batteries in response to needs arising from e-commerce (secure transactions), thin keyboards, electronic books, and the gift market. Looking forward beyond 2015, Toes will focus on wearable devices as the design of wearable devices will have no boundaries. Compared to traditional button cells, flexible thin-film batteries will break the barriers that constraint designers' creativity, thereby bringing forth opportunities beyond imagination. (Source：:Digitimes)