Electrochemical Energy Systems for Electrified Aircraft Propulsion

Batteries and Fuel Cell Systems
In this course, participants will learn about Electro-chemical Energy Systems (EES), with an emphasis on electrified aircraft propulsion and power applications. The course will present the fundamentals in chemistry, materials science, electrical, and mechanical engineering for various EESs including high voltage battery systems (Li-ion and beyond) and fuel cells (PEM, solid oxide fuel cells, and others). The challenges of each EES option will be examined as it applies to aircraft electrification, including: – Specific energy, efficiency, electrical, thermal, mechanical integration, operating conditions, and other technical considerations – Inherent hazards, risk severity, and available mitigation strategies – Ground handling, operations / maintenance, and recharging / refueling – Economics, life cycle considerations, infrastructure requirements, and certification challenges
– Recall elements of electrified propulsion and power (high level) including what is needed to make a successful EES for aircraft. – Discuss the inner workings and the ‘balance of plant’ associated with battery and fuel cell systems. – Explore the limitations, failure modes, and inherent risks for batteries / fuel cells and supporting subsystems in the context of flight / ground operations. – Consider future technological advancements, quantitative environmental and economic impacts on aviation, conceptual change to aircraft operations for end-users, and current government, industry, and regulatory activities.

This course is intended for technology and management professionals, students, and policymakers who want to understand EES technology fundamentals as well as their unique design and safety considerations and limitation in the context of electrified aircraft propulsion and power.

1. Lecture 1: Introduction / Overview: 
– This module will introduce concepts of aircraft electrification with respect to electrochemical energy system: batteries and fuel cells.
– A high level overview and comparison of different battery chemistries (including Li-ion, Li-Metal, Li-S, Li-Air, solid state Lithium, Sodium-ion) and fuel cell types (including Proton Exchange Membrane (PEM), alkaline, direct methanol, phosphoric acid, molten carbonate, and solid oxide) will be presented.
– High level trades and analyses, design, integration, operations, and safety considerations, and technology limitations will also be discussed.

2. Lectures 2 to 4: Batteries and Battery Systems
– Li-based battery cell components, material properties, processes, performance, and challenges.
– Pack considerations, battery management systems, thermal management, charging / discharging (rates and state of charge limits), and effect of different operating / environmental conditions.
– Cell-level risks / failure drivers, abuse conditions, thermal runaway (hazardous venting, propagation, fire, explosion), high voltage risks, aging / degradation, and environmental considerations. 
– Quality / control assurance, mitigations, protections / controls, containment, and regulations.

3. Lectures 5 to 7:  Fuel Cells and Fuel Cell Systems
– Polymer Electrolyte Membrane (PEM) fuel cell components, fuels, material properties, processes, and challenges.
– PEM stack considerations, electrical subsystem, fuel processing (including options for hydrocarbon fuel reformation or partial oxidation), air processing, water and thermal management, systems integration, durability, operational / environmental factors, and overall system efficiency.
– Solid Oxide Fuel Cell (SOFC) components, fuels, material properties, processes, stack level considerations, and challenges.

4. Lecture 8:  Charging / Fueling Infrastructure and Summary 
– Hydrogen as an energy carrier: properties, generation, storage, forms (liquid or gaseous), and safety considerations.
– Infrastructure requirements for charging / fueling, life cycle considerations (sourcing, manufacturing, operation, recycling / repurposing, and disposal), economics, and certification for aviation.
– Summary: Course re-cap, future considerations, and wrap-up.