Triboelectric Energy Harvester Design for Musculoskeletal Health Monitoring

Abstract

The triboelectric generator offers a promising avenue for generating electricity on a small scale, harnessing biomechanical energy. Through the development of a functional prototype, meaningful results have been obtained and documented in various environments. One scenario involved attaching the prototype to a belt worn on the lower back during treadmill jogging, while another involved manual movement of the prototype in a vertical direction while connected to an oscilloscope. These results, detailed in the respective sections, provide a solid foundation for further refinement of the prototype to enhance its output. The prototype's creation adhered closely to the original design, dimensions, choice of materials, and fabrication method. This approach facilitated rapid prototyping and yielded encouraging initial outcomes. While the prototype demonstrates scalability in electricity generation, its main limitation lies in its relatively low power output. By comparison, similar-sized prototypes leveraging the piezoelectric effect or thermoelectric methods could potentially yield higher power outputs. In summary, while the triboelectric nanogenerator prototype shows promise and represents a successful experimental endeavor, there remains room for improvement to maximize its power generation capabilities. The prototype demonstrates efficient power generation at low frequencies. Utilizing a resistor of 10.42 MΩ, the peak-to-peak voltage yields a power of 162 nW and an energy of 162 nJ, marking a 67.9% increase compared to a resistor of 24.96 MΩ. Experimentally, a prototype with two sliding plates and a 10 MΩ resistor achieves a maximum power output of 6.97 nW and an energy output of 6.97 nJ. Analytical calculations suggest a maximum energy output of 52.7 mJ and a power output of 52.7 mW when employing TPU, PLA graphite, and a freestanding mode of TENG. Figure 68 illustrates the experimental results obtained during treadmill jogging, presenting a graph of peak-to-peak voltage versus resistors. Blue columns represent peak-to-peak voltage values, while an orange line depicts resistor values, with voltage measured in volts and resistance in MΩ. With an estimated dielectric loss factor of about 50% (according to literature), the prototype's ideal peak voltage (Vp-p) and power generation are estimated at 1.8 V and 330 nW respectively, utilizing a 3 Hz motion and a 10 MΩ load. These estimations were derived using an Excel-based analytical modeling tool tailored for this specific prototype. However, during realistic body-on-treadmill experiments, the measured maximum peak voltage and power generation under the same conditions were approximately 1 V and 100 nW respectively. These results underscore the feasibility of the customized energy harvester design approach, which combines rapid 3D prototyping with tailored analytical modeling. Future endeavors will delve into the potential benefits of miniaturization and the utilization of thin films to enhance performance.