Planar CAPacitors for high temperature and mid-frequency operation

Introduction

Capacitors are ubiquitous in any electronic device, with aluminium and tantalum electrolytic capacitors used whenever larger capacitances are required. However, they suffer from reliability issues, especially when operating at high temperatures: a temperature increase of 10°C halves their life.

Concerns with Tantalum

In the case of tantalum, there is an additional concern: it is considered a critical raw material that generates environmental and societal concerns. It has been gaining a lot of attention from capacitor manufacturers in the search for an alternative technology solution.

Project Overview

The P.CAP project brings an alternative to aluminium and tantalum electrolytic capacitors: planar electric double layer capacitors (P.EDLCs) with enhanced performance at mid frequencies and high temperatures.

Advantages of EDLCs

EDLCs are energy storage devices with:

• A much larger DC capacitance than capacitors
• Excellent cyclability

However, current technology behaves as resistors at frequencies greater than 1 Hz. Under the right conditions, we have proven that they can operate at higher frequencies (1-200 Hz) while maintaining the merits of EDLCs: large capacitance and extended lifetime.

Thermal Stability

Moreover, when thermally stable ionic liquids are used as an electrolyte, they can operate at temperatures above 200°C.

Prototype Development

In the P.CAP project, a TRL7 prototype bipolar capacitor that can operate at >250°C, with an operating life of more than 1000 hours at this temperature and a rated voltage above 40 V, will be manufactured.

Application and Validation

This prototype will be used as a minimum viable product to validate the device in applications where reliability and high temperature are required, such as:

1. Mining
2. Electric vehicles

Project Goals

The main project goal is to reach a pre-commercial stage with a clear roadmap for upscaling production and starting pilot testing during the project.

Long-Term Vision

Our long-term vision is to further miniaturise the technology and provide a tantalum-free solution for smartphones, tablets, and printed circuit boards used in all electronic equipment.