|Solar cells are recognized for their conversion of photons into electricity, batteries are renowned for their long-term storage of that energy and cables are necessary for uniting the two. Less recognized but equally vital to any solar array is the diode board, the point at each cable junction that keeps energy flowing linearly from panel to storage cell, preventing any reversal of current. All diode boards work in essentially the same way, only allowing current to pass when their cathodes are charged negatively, but that does not mean they are all equal. Fralock’s all-polyimide diode boards, enhanced by our Adhesiveless Lamination Technology (ALT), are optimally suited for aerospace applications due to their sturdy yet flexible construction, lightweight but high electrical performance capability, as well as being electrostatically dissipative.
Any electronic component in space has to be protected from static charges that easily build up in a dry vacuum, but with so much energy passing through them, diode boards are among the more vulnerable. Some manufacturers manage static electricity by covering diode boards with an electrically conductive paint, but this is a fragile solution that can crack, peel, come lose during launch and requires delicate handling and expensive touch-up treatments. Other manufacturers add ground wires, adding another element of risk or failure. Fralock bypasses these risks by mechanically bonding a static dissipative polyimide layer with our ALT to the top surface, making it a physical part of the diode board itself.
Most manufacturers use polyimides when constructing diode boards but must use an adhesive material like PTFE to bind the layers in order to enclose the board’s circuitry. The added adhesive layer adds risk and impedes performance. Fralock’s ALT completely bonds the layers to each other, essentially encasing the circuitry in a single, tough sheet of insulation thereby reducing risk and increasing performance.
The absence of adhesives provides a number of advantages. While other polyimide diode boards have a tendency to delaminate or burst apart under stress, ours can be bent and twisted without reducing performance or risking damage. They are unaffected by levels of radiation that would disintegrate PTFE, a quality that’s integral for components exposed to the sun’s unfiltered radiation. Our diode boards tolerate temperatures from -269°C to 220°C (–516.2°F to 428°F).
Using ALT also allows our diode boards to have about two-thirds the volume and weight of other polyimide versions, an asset for aerospace applications, which have extremely tight space and weight constraints and launch costs of thousands of dollars per pound.
Like the rest of our Adhesiveless Laminate products, our diode boards are stronger, more resilient, higher-performing and all-around better-suited for space than anything else on the market.