University of Twente Student Theses
Epoxy-ceramic based NTC temperature sensors for improved humidity stability and low curing temperatures
Hatakeda, Joel Benavides (2022) Epoxy-ceramic based NTC temperature sensors for improved humidity stability and low curing temperatures.
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| Abstract: | Temperature measurements are used in many industrial applications as a tool for controlling or monitoring a process. In batteries, temperature is an important parameter to make sure the charge and discharge is performed efficiently and, thus, enlarge the lifetime of the device. Holst Centre developed a flexible printed NTC thermistor, based on a Manganese-Nickel ceramic dispersed on a polymer matrix, that has the accuracy as well as the electrical and mechanical performance needed for such task but presents 2 main disadvantages: only PI films are used as flexible substrate because of the curing temperature of the NTC composite (above 200 ℃) and performance of the sensor is affected by humidity. A solution based on an epoxy-ceramic composite was presented to tackle the issues mentioned above. The implications of changing the polymer in the formulation were studied by assessing the percolation limit of the new composite and understanding the influence of pressure as well as the electrode design. Humidity stability was tested based on the properties of the epoxy and the electrode material. Results showed that the epoxy permitted lowering down the curing temperature of the NTC ink (down to 180 ℃) which allowed to increase the range of materials to be used as flexible substrates (PEN, PET). Influence of humidity in the sensor’s performance decreased with the new composite but is still present (changes in thermistor’s resistance due to humidity, but not temperature, are above 1%). Further optimization of the formulation or an external humidity barrier should be considered for future works. |
| Item Type: | Essay (Master) |
| Faculty: | EEMCS: Electrical Engineering, Mathematics and Computer Science |
| Subject: | 53 electrotechnology |
| Programme: | Electrical Engineering MSc (60353) |
| Link to this item: | https://purl.utwente.nl/essays/92864 |
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