Development of Regenerative Fuel Cell Systems for Space Applications

Manuel Hempel NTNU Hydrogen workshop, 03.12.2019, Trondheim

About Prototech

• Established: 1988

• Owner: NORCE (100%)

• Employees: 40

Maritime Renewable Energy Space Environment

Energy supply for Space Applications

• 99% of all spacecraft are powered by photovoltaic

• Nuclear power becomes dominant beyond Jupiter orbit

• Most missions require energy storage for eclipse periods

• Batteries are baseline for storage

• Battery energy density is too low for certain mission scenarios

• RFCS have the potential to achieve higher energy densities than current battery based systems

Equinox

RFCS in general

• Energy Storage System

• Possible alternative to batteries

• Suitable for high power applications

• Main advantage – Potentially higher energy and power

densities achievable

– Enabling Technology for high power missions

– Synergies with other SC subsystems

• Main disadvantage – Lower TRL

– Increased complexity

Electrolyser

Fuel Cell

H2 O2 H2O

RFCS in more detail and RFCS challenges for space

Loops • Green: cooling loop • Red: hydrogen loop • Light blue: oxygen loop • Dark blue: water loop

Redundancy

no redundancy

redundancy

RFCS technology development at Prototech

“Demonstration of a closed loop H2/O2 RFCS” (2009 – 2012)

• In-house made liquid-cooled HTPEM FC stack

• PEM ELY (semi-commercial)

• 1 kW-class FC and ELY

• Closed loop RFCS

• Active gas circulation through FC stack

• Commercial BoP components

• 1350 charge – discharge cycles performed

• Degradation of 0.0018 V/cycle @ 0.133 A cm-2

• 1 kW

• 180 – 200 °C

• 0 - 10 bar

• 91 cm2

• 34 cells

• 0 – 40 A

• Aim: 1 kW/kg

• Liquid cooling

• Thin metal plates

• 4.2 kW (1kW short)

• 80 °C

• 100 bar (O2 & H2)

• 126 cm2

• 33 cells (7cell short)

• 1.75 V/cell @ 1 A cm-2 @ 100 bar

• 0.85 kW/kg

HT PEMFC SPACE STACK HP PEMELY

Prototechs Stack Development

Challenges in Space

Environment • -170 -> 120°C • Radiation • Micro- g • Fractional- g • Launch

• Multi-g • Vibration • Shock loads

Phase separation • No inherent phase

separation in zero- g • Problem in tanks,

separators, sensors etc. • Gravity independent

technologies required

Heat Management • No convection • Complicated thermal

management • Waste heat needs to

be radiated to space

Reliability • 15 years lifetime • No maintenance • No purge

possibility • Reduncancies->

system complexity

Energy storage for space, Moon and Mars: outlook

O2 H2

H2O

H2

O2

Life Support System

Propulsion System

Energy System

In-Situ Resource Utilisation

RFCS H2O

H2O

O2 O2

H2

H2 O2

power

Regolith

CO2

(Mars)

O2

H2O

food

H2O

CO2

FC ELY

RFCS technology development at Prototech

• Projects spanning 2006 - present

• Financed through the European Space Agency

• Development and demonstration of stacks (FC, ELY), RFCS and H2 storage systems:

• “Hydrogen Storage Technologies” • “Regenerative H2/O2 Fuel Cell” • “Innovative Gas Storage on Satellites” • “Advanced Energy Storage System” • “Demonstration of a closed loop H2/O2 RFCS” • “Metal Hydride Hydrogen & Heat Storage System” • “Water Propulsion System” • “Regenerative Fuel Cell Systems Technologies

Development” • “Alternative Energy Storage Solutions for Lunar Night

Survival in Human Exploration Scenarios”

RFCS in 3 scenarios - Environment

HAPS • Gravity

• Low pressure

• 14 h sunlight, 10 h darkness

• - 50 °C

GeoSat • Micro-g

• Vacuum

• Max 72 min darkness

• - 170° - +120°C

Lunar Exploration • Fractional-g, micro-g

• Vacuum

• 14 days sunlight /darkness

• -173° - + 127°C

RFCS in 3 scenarios - Specifications

HAPS • 500 kWh

• 50 kW

• 365 – 1825 cycles

• PEM FC, PEM ELY

GeoSat • 47 kWh

• 30 kW

• 1350 cycles

• HTPEM FC, PEM ELY

Lunar Exploration • 20 kWh

• < 1 kW

• 2 cycles

• PEM FC, PEM ELY

RFCS in 3 scenarios

Conclusions, current and future work

• Current space certified batteries (100-170 Wh/kg) have too low energy densities for certain future mission scenarios

• RFCS have the potential to achieve the required energy densities

• Synergies with other SC subsystems are key for flight application

• Current bottleneck: availability of light weight high pressure (100+ bar) gas tanks

• Space trends: – Pump-free systems(higher reliability, less vibration): Passive Cooling, Dead end stack operation

– Phase separation based on membranes

– Cathode vapour feed ELY stacks are being investigated for space applications

Future applications

Future applications

Future applications

For more information Prototech AS

Manuel Hempel Phone: +47 464 17 348

manuel.hempel@prototech.no

Thank you!

HERACLES mission

• Human-Enhanced Robotic Architecture and Capabilities for Lunar Exploration and Science

• Led by ESA in collaboration with JAXA and CSA

• Demonstration robotic mission to evolve into a future human mission

• To land on the far side of the Moon near Lunar south pole (Schroedinger crater) in 2026, deploy a long-range rover, collect 15 kg of samples and deliver to the “Gateway” station, from which astronauts take the samples to Earth using Orion infrastructure

HERACLES

Getaway, HERACLES and Orion

Applications of RFCS on the Moon

Manned rover • 1700 kWh

• 5 kW

Lunar base • 17 MWh

• 50 kW

Robotic exploration • 20 kWh

• 200 W

Fuel cell development at Prototech

• HTPEM fuel cells – Stack design

– System design

– Auxiliary components

• PEM water electrolysers – High pressure ELY stack

• SOFC – Stack design

– System design