Pressure film gives snapshot of manufacturing process

Various types of pressure film have been around for a long time in electronics. One use is to monitor how well a heat sink, for example, is contacting pcb surface.

Here’s another application: Monitoring the lamination or calendaring process in batteries. Pressurex is a pressure sensing film that, when placed between the lamination platens the film permanently changes color proportionally to the laminating pressure. You pull the film out, look at the color distribution, and get a pretty good idea of the alignment of mating rollers and lamination platens.

Not too many of us are involved in the actual manufacture of batteries, but many of us design with them, and almost all of us use them. From the Pressurex web site, here are how the lamination process plays out in the major battery technologies:

– Lithium-Manganese Dioxide (Li/MnO₂) Pouch cells – Similar to the P-80 battery, these cells are laminated into bags. In addition, the current collector for the lithium is laminated to the inside of the bag through using a small pneumatic or hydraulic press with heated platens.

– Lithium-ion (Li-ion) Polymer Cells — The positive and negative electrodes for these cells are cast from slurries containing the active ingredients, binders, and conductive media. They are then laminated to their expanded-metal current collectors and a separator layer is also cast. Then, the positive and negative electrodes are laminated to the separator using either heated double-roll laminators or parallel-platen presses.

– Metal-Air Cells (These have been in the news a lot lately due to announcements in Zinc-air technology) — Metal-air cells utilize an air electrode consisting of a carbon layer, nickel mesh, a second carbon layer, and Teflon film. These four layers are laminated together in a continuous web process using a laminating press.

The flexible film measures pressures from 2 - 43,200 PSI and can be hand- or laser-cut to any size or dimension. It’s available in eight pressure ranges. 

Want to try it yourself? Contact the manufacturer, Sensor Products at info@sensorprod.com.