Pagoda-Shaped Triboelectric Nanogenerator With High Reliability for Harvesting Vibration Energy and Measuring Vibration Frequency in Downhole

Drill string vibration is very critical to the drilling technology, which needs to be measured in real-time. This paper proposes a highly reliable pagoda-shaped triboelectric nanogenerator which can measure the downhole vibration frequency in self-powered model and harvest the downhole vibration energy to try to power other downhole instruments based on the Chinese pagoda. The designed pagoda-shaped triboelectric nanogenerator has seven layers, and charges are generated by floating contacts of two adjacent layers pasted with PMMA and Kapton, respectively. The sensing tests show that the measurement range is 0 to 5 Hz, the measurement error is less than 5%, and the minimum output signal amplitude difference is about 28 V while the maximum is about 155 V, which shows a higher signal-to-noise ratio. In addition, the pagoda-shaped triboelectric nanogenerator with seven layers can still work normally when the number of undamaged layers are two or more, which shows a higher reliability. The output power tests show that the maximum power is about 4090 × 10
^-10
W when all layers of the pagoda-shaped triboelectric nanogenerator are connected in series with a 470 k ohm resistance and the vibration frequency is about 3 Hz. Compared with the traditional downhole drill string measurement method, the multilayer structure of the pagoda-shaped triboelectric nanogenerator makes it has higher reliability, higher output power, and saves the radial dimension space, which are very suitable for actual drilling requirements of working conditions.