Session 17: Power Technology
Develop of a Very Thin "Flexible" Battery and Process for Manufacturing
Wednesday, June 21, 2017
5:20 PM - 5:40 PM
This challenging project required a very careful analysis and definition of requirements as well as bringing together a wide range of technical concepts and data points and then stepping back and re-defining the steps of the battery cell manufacturing process.
The first element, which was absolutely critical to the success of the project was the definition of "flexible" - not the literal definition of flexible, but what did the product have to do. By understanding the requirements and specifying them as having to bend back and forth over a 4" roll a limited number of times and tolerate gentle flexing in use (not being folded over 180 degrees), it was possible to define the required mechanical deformations.
The second element was the product analysis and conceptual development which took base knowledge of lithium ion battery cell construction and looked at questions such as "what are the necessary elements of a lithium ion cell? What happens when a lithium ion cell is bent? What holds the cell together. What are the causes of cell failure? One of the key approaches to reduce the thickness was to discard the thick heavy flexible pouch packaging and make the electrode current collector multifunctional - acting as the electrode support, electrical connection and the hermetic outside packaging for the moisture sensitive chemistry. This multifunction approach provided an additional benefit in that the package seal could be an ultrasonic metal-to-metal weld providing a far thinner and true hermetic seal.
However, this multifunctional component design did not lend itself to traditional lithium ion electrode manufacturing processes or cell assembly techniques. It was necessary to reach into other industries for technology to commercially apply fairly thick electrode coatings in specific patterns (screen printing or 3D printing) and an ultrasonic rotary seamer to seal the edges. It was also necessary to develop a ceramic separator to withstand the processing and bending pressures.
The thin cell contains only a single anode and cathode folded around it. The assembly involves a series of sequential indexed individual steps which can be implemented as a manual or easily automated assembly line type of process. While the process has not yet been automated, the project included the assembly of a manual line and demonstration of production of reproducible viable prototypes.
Dr. Manning joined Custom Electronics in 2015 to support CEI entering the lithium battery business. Jim brings a history of innovation and success. From ruggedized cells for the Atlas V with over 40 missions and pressure tolerant cells for the Phoenix X-Bot that took the photos of the Titanic, to a separator that prevents overcharge and structural batteries that can be used as wings and flexible batteries for the FlexTech leaflet project.
Jim is a PhD ChE and his technical experience includes lithium (ion, polymer, metal) cell design and manufacturing, super capacitors, coating, battery design, and assembly. He also has manufacturing experience in plant design and construction, start-up, process scale-up and production.
Dr. Manning has held many responsible positions: President/CTO of Lithium Battery Engineering, COO/CTO of Freya Energy, CMO of Planar Energy, Director of Engineering of Electro Energy, and President/COO/CTO of Lithium Technology / Managing Director of GAIA (Germany).