An investigation of the feasibility of a spacecraft multifunctional structure using commercial electrochemical cells
Year: 2009
Type: dissertation
Abstract: Multifunctional structures offer the potential for large savings in the mass and cost of spacecraft\nmissions. By combining the functions of one or more subsystems with the primary structure, mass is\nreduced and internal volume freed up for additional payload, or removed to reduce structural mass.\nLithium batteries, increasingly preferred to other power storage solutions, can be employed to produce\nsuch structures by incorporating prismatic batteries into structural sandwich panels. Such\n“powerstructures” can reduce the mass and volume of the power storage subsystem.\n\nAfter reviewing the current work in the field of multifunctional structures, this thesis describes the\nobjective of the research, to examine the usefulness and feasibility of a multifunctional structure based\non commercial lithium cells and sandwich structures. The next section presents a study that quantifies\nthe benefits of this technology, showing maximum savings of up to 2% of total mass, and 0.5-1% for\ncommon spacecraft designs.\n\nThe next section describes experimental investigations into the mechanical suitability of commercial\nPLI cells for use in the multifunctional structure. Firstly, the effect of launch vibration was considered:\n15 and 25 grms tests showed no measurable loss in electrical performance. Then, the structural attributes\nof the cells were measured using a dynamic shear test. The shear modulus of the cells was found to be\nrather lower than that of an aluminium honeycomb core material.\n\nConsideration is then given to the practical implications of a multifunctional structure. The feasibility\nof manufacturing is assessed through the construction of a trial panel, showing that the cells lose some\ncapacity and suffer an increase in internal resistance in a high-temperature adhesive cure and that a\ncold-bonding process may thus be preferable. The resultant panel was then vibrated on an\nelectrodynamic shaker to both assess the resilience of the cells and test the reliability of finite element\nmodels. These finite element models are then used for a simple optimisation, showing that a welldesigned\npowerstructure can have structural performance comparable to a conventional design.\n\nThe final section weighs the benefits of using a multifunctional structure against the potential\ndisadvantages in terms of cost, design time and flexibility, as well as assessing the validity of assumptions\nmade in the work. The conclusion is that a multifunctional structure of this type, whilst not worthwhile\nfor all mission types, could potentially increase the feasibility of short-term spacecraft missions using\nsmall satellites (of the order of 100 kg) with large energy storage requirements.
Author: Samuel Roberts
Language: English
Subfield: Automotive Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W618227626