Cool Tech: High Power Lasers – Fuel Cells
By Mark Norfolk on Monday, April 5th, 2010
EWI has a great collection of high power lasers that are being used for manufacturing items from small batteries to 48” gas transmission pipelines. This is the first in a series of blogs exploring these cool toys.
The challenges in fuel cell product development are great. The technologies of electro-chemistry and material performance are very complex and time-consuming to resolve. Thus, it is not surprising that the bulk fuel cell development effort to date has been devoted to these areas. Now that the efforts are yielding increasingly successful design solutions, it is essential that the manufacturing technology and cost challenges be overcome. In particular the metallic interconnect poses many manufacturing challenges. This component is a fundamental element in fuel cells and hundreds of thousands, if not millions, of them will be required in a future that embraces fuel cell products.
Each interconnect can have several feet of welds that join two thin foils. In a fuel cell there are numerous interconnects, meaning that a single fuel cell can have several hundred feet of welds. If these welds have even a small pin hole leak, eventually the fuel cell will experience what the industry politely calls a ‘thermal event.’ Thus, the high potential demand for a high-volume manufacturing, demands new manufacturing technology that is very fast and very high quality (six sigma is not good enough).
EWI has developed a unique capability in high speed laser welding for fuel cell applications. The main toy we play with is a high power fiber laser attached to a magnetically driven x-y table. The X-Y table allows high travel speed macro motion over several feet while a magnetically aimed mirror controls fine motion over a 4”x4” area. The combination of the two motion systems in series allows very high accuracy and welding speeds up to two meters a second. The attached video demonstrates the same capability on simulated battery tops making 30 perfectly circular welds in less than 2 seconds. In the first video you can see the system make ‘welds’ on a piece of black paper for simple visualization. In the second video you can see the same welds on metal that is the same thickness as typical battery components.