A Minimal Volume Hermetic Packaging Design for High-Energy-Density Micro-Energy Systems

Xiujun Yue,Akaash Padmanabha,James H Pikul,Jessica Grzyb

doi:10.3390/en13102492

Abstract

Hermetic packaging is critical to the function of many microscale energy storage and harvesting devices. State-of-the-art hermetic packaging strategies for energy technologies, however, are designed for macroscale devices and dramatically decrease the fraction of active materials when applied to micro-energy systems. We demonstrated a minimal volume hermetic packaging strategy for micro-energy systems that increased the volume of active energy storage materials by 2× and 5× compared to the best lab scale microbatteries and commercial pouch cells. The minimal volume design used metal current collectors as a multifunctional hermetic shell and laser-machined hot melt tape to provide a thin, robust hermetic seal between the current collectors with a stronger adhesion to metals than most commercial adhesives. We developed the packaging using commercially available equipment and materials, and demonstrated a strategy that could be applied to many kinds of micro-energy systems with custom shape configurations. This minimal, versatile packaging has the potential to improve the energy density of current micro-energy systems for applications ranging from biomedical devices to micro-robots.

Highlights

Hermetic packaging technologies that prevent internal components from reacting with oxygen or moisture in the air are critical for numerous microscale technologies, including sensors, batteries, super-capacitors, energy harvesters and other energy systems [1,2,3]
For example, have a minimum hot sealing width of 3 mm, which accounts for 12% of the total cell area in a 10 × 10 cm2 macroscale battery, and allows 88% of the cell area to be available for energy storing materials
We developed a low volume fraction micro-packaging strategy designed to increase the volumetric and gravimetric energy density of micro-energy storage technologies

Summary

Introduction

Hermetic packaging technologies that prevent internal components from reacting with oxygen or moisture in the air are critical for numerous microscale technologies, including sensors, batteries, super-capacitors, energy harvesters and other energy systems [1,2,3]. The microbattery market, for example, is predicted to grow nearly 5× between 2019 and 2025 as a result of new Internet of Things (IoT) and medical devices [4], but current hermetic packaging technologies limit microbattery energy densities to a fraction of macroscale batteries. For example, have a minimum hot sealing width of 3 mm, which accounts for 12% of the total cell area in a 10 × 10 cm macroscale battery, and allows 88% of the cell area to be available for energy storing materials. When the same pouch cell packaging is applied to a 1 × 1 cm microscale cell, the seal uses 84% of the cell area and leaves only 16% of the area for energy storing materials. If the energy storing materials had a combined energy density of 1000 Wh/L, the macroscale cell would have 880 Wh/L energy density, while the microscale cell would have only 160 Wh/L

Methods

Results

Conclusion