This work consists in the development and design of an energy harvesting device to supply power to the new generation pacemakers, miniaturized leadless implants without battery placed directly in heart chambers. After analyzing different mechanical energy sources in the cardiac environment and associated energy harvesting mechanisms, a concept based on regular blood pressure variation stood out: an implant with a flexible packaging that transmits blood forces to an internal transducer. Advantages compared to traditional inertial scavengers are mainly: greater power density, adaptability to heartbeat frequency changes and miniaturization potential. Ultra-flexible 10-µm thin metal bellows have been designed, fabricated and tested. These prototypes acting as implant packaging that deforms under blood pressure actuation have validated the proposed harvesting concept. A new type of electrostatic transducer (3D multi-layer out-of-plane overlap structure with interdigitated combs) has been introduced and fully analyzed. Promising numerical results and associated fabrication processes are presented. Also, large stroke optimized piezoelectric spiral transducers including their complex electrodes patterns have been studied through a design analysis, numerical simulations, prototype fabrication and experimental testing. Apower density of 3 µJ/cm3/cycle has been experimentally achieved. With further addressed developments, the proposed device should provide enough energy to power autonomously and virtually perpetually the next generation of pacemakers.

Ce travail consiste à développer un système convertissant une partie de l’énergie mécanique du cœur en électricité pour alimenter les stimulateurs cardiaques de nouvelle génération, implants sans sonde ni batteries implantés directement dans la cavité cardiaque. Après études de différentes sources d’énergies et concept associés, l’option liée à la pression sanguine, appliquant sur une partie souple du boîtier de l’implant des efforts transmis à un transducteur interne les convertissant en électricité, s’est révélée la plus prometteuse. Cette solution présente les avantages principaux suivants par rapport aux systèmes inertiels usuels : grande densité de puissance, adaptabilité au rythme cardiaque et potentiel de miniaturisation. Un boîtier ultra-souple électro-déposé de 10 µm d’épaisseur en forme de soufflet a été modélisé, fabriqué et caractérisé, validant ainsi le concept de récupérateur proposé. Un transducteur électrostatique novateur (3D multicouche à peignes interdigités et à chevauchement hors-plan), étudié par des modélisations analytiques et numériques, est en cours de fabrication. Selon l’électronique associée, ce transducteur promet une grande densité d’énergie extraite. Un transducteur piézoélectrique micro-usiné en forme de spirale et à électrodes micro-structurées, est également présenté. Les défis spécifiques des spirales dontla flexibilité permet d’augmenter l’énergie mécanique d’entrée sont étudiés notamment par simulation numériques, et des prototypes ont été micro-fabriqués et caractérisés. Au final, une énergie de 3 µJ/cm3/cycle est obtenue et de nombreuses perspectives d’amélioration permettent d’envisager une puissance au moins 10 fois supérieure. / This work consists in the development and design of an energy harvesting device to supply power to the new generation pacemakers, miniaturized leadless implants without battery placed directly in heart chambers. After analyzing different mechanical energy sources in the cardiac environment and associated energy harvesting mechanisms, a concept based on regular blood pressure variation stood out: an implant with a flexible packaging that transmits blood forces to an internal transducer. Advantages compared to traditional inertial scavengers are mainly: greater power density, adaptability to heartbeat frequency changes and miniaturization potential. Ultra-flexible 10-µm thin metal bellows have been designed, fabricated and tested. These prototypes acting as implant packaging that deforms under blood pressure actuation have validated the proposed harvesting concept. A new type of electrostatic transducer (3D multi-layer out-of-plane overlap structure with interdigitated combs) has been introduced and fully analyzed. Promising numerical results and associated fabrication processes are presented. Also, large stroke optimized piezoelectric spiral transducers including their complex electrodes patterns have been studied through a design analysis, numerical simulations, prototype fabrication and experimental testing. Apower density of 3 µJ/cm3/cycle has been experimentally achieved. With further addressed developments, the proposed device should provide enough energy to power autonomously and virtually perpetually the next generation of pacemakers.