Dr. Tom Barrera
3 Things You Should Know About Space Li-Ion Batteries in 2019
Updated: Aug 2, 2019
Ever since the 2001 launch of the European Space Agency PROBA-1 LEO spacecraft, the space battery community has been deliberate in transitioning from heritage nickel-hydrogen to lithium-ion battery (LIB) based power systems. Nearly 20 years later, space LIB technology continues to mature relative to the increasing demand for higher power and more reliable spacecraft. Over the next few years, as the first long duration mission spacecraft utilizing LIB’s reach end-of-life, the aerospace community expects to learn even more about space LIB capability.
LIB-X Consulting is proud to continue our role in shaping the future of LIB technology for space applications. Let’s take a close look at our 2019 LIB technology forecast:
The debate over the pro’s and con’s of using the small COTS vs. large Li-ion cell approach for space LIB designs continues to polarize the aerospace battery community. As such, small-cell based “brick-type” LIB’s have been adopted into spacecraft applications traditionally dominated by large-cell based LIB architectures. Although large aerospace Li-ion cell design solutions have always been challenged to compete with small Li-ion cell designs on cost ($/kWh) and cell-level specific energy (Wh/kg), leading domestic satellite manufacturers such as Lockheed-Martin, Space Systems Loral, and Boeing continue to baseline large-cell based LIB’s for high reliability long duration space missions.
In 2019, expect to see the debate heat up over use of high specific energy (>250 Wh/kg) 18650 cell designs (w/o positive temperature coefficient safety devices) for next-gen LIB space batteries. The ongoing electrified transportation market-driven transition from 18650 to 21700 and 20700 small cell designs will begin to add obsolescence risk to heritage aerospace programs married to 18650 cell-based LIB’s. Large Li-ion cell suppliers will continue to compete with small cell LIB design solutions on cost, specific energy, and modularity.
Dialing Up Market Pressure
Innovation in lithium-ion battery space power systems development has largely been paced by terrestrial commercial market achievements in Li-ion cell technology. This includes advances in specific energy, cycle life, and safety devices. New cell cathode, anode, and electrolyte materials are typically qualified for commercial electronics or electric vehicle applications before aerospace Li-ion cell manufacturers follow suit.
In 2019, the conservative nature of aerospace Li-ion cell manufacturers will continue to be driven by incremental acceptance of evolutionary changes to commercial Li-ion cell technologies. Materials obsolescence risk associated with long-term purchase agreements, typically executed between spacecraft and Li-ion cell manufacturers, will remain a long-term focus for the satellite customer community.
Safety is King
While mass and cost requirements continue to drive space LIB design solutions, safe designs tolerant of catastrophic cell-to-cell thermal runaway are now required for many government and commercial space LIB power systems. As a result, battery safety has become a key discriminator in Li-ion cell trade studies supporting new human space flight and unmanned space platform applications. The threat of LIB over-charge hazards appears to be in the rear-view mirror of most power system designers due to implementation of sophisticated system-level dual-fault tolerant hazard controls. However, the recent release of RTCA DO-311A has set a new standard for the aerospace community on verifying that LIB’s will perform their intended functions safely under conditions encountered in operations.
In 2019, the impending release of new space industry standards (such as AIAA S-136, AFSPC-91-710, and SMC-017) to include stricter requirements for fielding thermal runaway tolerant LIB designs will have a significant impact on the aerospace battery industry. Requirements compliance will drive LIB engineers to incur unexpected mass (and cost) penalties due to the addition of new LIB-level safety design features intended to mitigate propagating thermal runaway. In order to meet spacecraft mission assurance and reliability requirements, expect to see new requirements levied on LIB’s designed for unmanned space applications for mitigating catastrophic thermal runaway.
What are your predictions for 2019?