Agenda

Supercapacitors bring many benefits to applications where a fast discharge is required, and provide a much higher energy density than electrolytic capacitors at a much lower physical footprint. However, supercapacitors are still produced as discreet components and are still bulky for certain applications. In this work we demonstrate the integration of supercapacitors into the fabric of flexible printed circuits. Flexible printed circuits (FPCs) typically consist of layers of Cu and polyimide and are commonplace in most electronic apparatus, typically as interconnectors onto which components are attached. We demonstrate a supercapacitor which fully integrates with the FPC production process and can be easily manufactured by any FPC producer. The embedded supercapacitor provides low ESR energy storage without the need for an additional discrete component. An areal capacitance of ~200-250mF/cm2 has been demonstrated, and the resulting device is tolerant to flexibility. Reflow solder tolerant devices are currently in test. A few practical use examples will be shown.

o A 9.5 kWe proton exchange membrane fuel cell system was passively hybridised with a 33x1500 F supercapacitor pack

o Supercapacitors acted as a low pass-filter to the fuel cell, allowing for load smoothing without the need for a DCDC converter thus reducing cost

o Increases in fuel cell efficiency, durability and performance were achieved by hybridisation with supercapacitors

o High frequency load limitations were identified above which the load smoothing capabilities of the supercapacitors diminished