Flexible, printed & thin-film battery market to reach $400m

 IDTechEx thinks Li-ion batteries with special form factors combined with wireless charging will come to the market earlier than batteries with intrinsic flexibility. By 2025, the market size for flexible, printed and thin-film battery will reach over $400m, as stated in the IDTechEx Research report Flexible, Printed and Thin Film Batteries 2015-2025.

Stretchable batteries and Li-ion batteries with special form factors are good candidates for wearable and flexible devices and they may win the future. However, these batteries are not truly flexible. The innovation is the design of cells arrangement, there is no new chemistry involved, therefore most batteries can be mass produced easily based on traditional battery manufacturing techniques.

As published by Arizona State University, the use of Japanese art of Kirigami tricks makes the traditional Li-ion batteries flexible. This approach represents another strategy for future battery development.

The Kirigami stretchable Li-ion battery developed by Arizona State University can be sewed into an elastic band and is a good choice for wearable devices such as smart watches, smart bracelets, smart headbands, etc. It can extend to more than 150% of its original size while keeping its function. The battery prototype has successfully powered a Samsung Gear 2. If covering the entire area of an elastic band with a dimension of 25x3cm, the energy capacity can achieve 700mAh. As a comparison, the battery capacity used in Samsung Gear Fit is 210mAh.

The Kirigami battery is only one example. There are more Li-ion batteries with special form factors emerging such as needle batteries, cable batteries, terraced batteries and stretchable batteries. Consumer electronics giants are moving into the battery business for wearables as well. For details please refer to the article Apple, Samsung, LG Chem move into the flexible batteries business and report Flexible, Printed and Thin Film Batteries 2015-2025.

Battery problems are more of a material choice problem than an engineering problem. However, finding a workable chemistry system comparable to Li-ion is not easy. Although at the moment there are many new battery systems being researched such as aluminium ion, magnesium, lithium sulfur, lithium air, sodium ion batteries, they are either perform worse than Li-ion or have a long way to go.

Batteries can be made flexible if they are thin enough. However, for a fixed battery system, thinness will further reduce the battery capacity for the same area. Certain battery thickness is required if very large footprint is not preferred for high capacity. One of the biggest issues that occurs in intrinsic flexible batteries is the crack introduced by bending and curving, which results in reduced life time. Truly flexible batteries seems to have a long way to go, although we have seen some prototypes. Those prototype batteries still need further R&D to ensure the safety, reproducibility, cycle life, capacity and other issues.

Due to the limited volume, most commercial thin-film batteries including printed and non-printed versions are mainly for micro-power applications such as skin patches, smart cards, RFID, wireless sensors, etc. High energy density batteries may overcome the limited volume issue. However, this normally involves new chemistries and battery systems. IDTechEx believes it is a long process. In addition, large capital and effort may be required if they are not based on traditional battery manufacturing facilities. Thin batteries for high capacity applications will only be a long-term business plan.

Considering the long development time for new batteries systems and intrinsically flexible batteries, companies are looking for alternative solutions such as wireless charging and other energy harvesting methods. In the near future, batteries in wearables will be combined closely with those approaches.

New battery designs have brought another approach to make flexible batteries. Li-ion batteries with special form factors with wireless charging may win the feature for high capacity wearable devices and/or consumer electronics.