Pressure Paper Sensor
The term “Pressure Paper Sensor” refers to either Fujifilm Prescale® or Pressurex-micro®. These pressure sensing films, distributed by Sensor Products, respond to pressure that is exerted between any two objects. Their response is a color change that is proportional to the amount of pressure. Furthermore, if the pressure over the area of contact varies, the Pressure Paper Sensor shows the distribution of pressure.
Peyman Taheri, Scott Hsieh, and Majid Bahrami of Simon Fraser University, Burnaby, BC, Canada, used Fujifilm Prescale® as a Pressure Paper Sensor to aid in the study of Electrical Contact Resistance (ECR) in Li-ion batteries for hybrid and electric vehicles. (“Effects of Electrical Contact Resistance on External Energy Losses in Lithium-ion Battery Packs for Hybrid and Electric Vehicles,” presented during the 5th International Conference on Energy Sustainability & 9th Fuel Cell Science, Engineering and Technology Conference, August 7–10, 2011, in Washington, DC.)
High ECR in Li-ion batteries can result in energy losses as high as 20%. Many of these losses can occur at the junction between the electrode bar and the current collector bracket, and it is known that low contact pressure is a major contributor to high ECR. Therefore, Peyman Taheri studied this interface, which is shown in Figure 1, using the Fujifilm Prescale® Pressure Paper Sensor. Figure 2 shows results of the Pressure Paper Sensor tests.
Fig 1: Electrode Bracket Assembly
Fig 2: (a) Results of Tests Using Fujifilm Prescale® Pressure Paper Sensor and (b) Graphical Representation of Pressure in the Electrode Bracket Assembly
The Pressure Paper Sensor was inserted between the electrode bracket and brass or copper electrode bars. In both instances, high contact pressure (deep magenta color) is seen in the vicinity of the bolts. This is indicative of good electrical contact. However, low pressure areas are found between the bolts and areas adjacent to both bolts. This can result in an increase of ECR.
Additional information on Pressure Paper Sensors can be found in product links to Pressurex-micro® and Fujifilm Prescale®. More information can be found in the Glossary under the following topics: Fuji Paper, Fuji Pressure Film, Prescale®, Prescale® Fuji Film, Pressure Film, Pressure Indicating Film, Pressure Measurement Film, Pressure Paper, and Pressure Tape.