Solicore, Inc., Lakeland, FL USA
The company is a producer of thin film batteries of less than 0.45mm in thickness. Battery operated devices have grown smaller and smaller while energy demands have increased as the need for increased functionality has grown. This need has led designers, which would normally use conventionally sized batteries, to consider other types and form factors. Products such as powered display transaction cards, RFID/sensor tags, and medical device patches have created a market for thin film batteries.
The following provides a brief review of battery construction. All batteries are basically made up of an anode (lithium in this case) and a cathode (MnO2 in this case), separated by a mechanical barrier (separator layer) designed to prevent internal electrical connectivity. The trick with the separator layer is to minimize resistance within the battery by being thin while not too thin as to promote soft shorts, limiting the life of the battery.
Without doubt, the single greatest technological advancement thus far has been the ability to screen print the anode (lithium). This achievement allows for complete flexibility in dimensional battery characteristics without the concern/difficulty associated with handling coiled metallic lithium.
The ability to formulate inks based upon the coated version of the cathode and PME (separator layer) for application in screen and inkjet printing has also been a great success. The key to this success has been overcoming interlayer adhesion issues that occurred from the multiple layers required to achieve the necessary coat weight.
The printed conductors, insulators, and adhesives that are all functional equivalents to their corresponding traditional non-printed counterparts are also a reflection of the maturing nature of the science that is printed electronics.
The scalability and superior economics of the digitally printed battery combine to form an even larger overall success. While the coated battery process performs well, it has limited scalability and rather fixed economics that have driven the digitally printed battery to become a reality.
Initially Published in the IPC Proceedings