electrochemistry

1. National Aeronautics and Space Administration Exploration Technology Development Program Energy Storage Project Material Assessments and Manufacturing Approaches for Advanced Lithium-ion Cell Designs Introduction Saft America, Inc. is the Industrial Partner for the "Advanced Lithium-Based Chemistry Cell Development“ Battery Development Contract NNC09BA04B.  Saft America, Inc. is responsible for the screening and scale-up of battery cell component materials developed via a combination of NASA in-house and NRA contracted efforts; the fabrication and delivery of evaluation cells; and the design, fabrication and delivery of advanced High-Energy (HE) and Ultra-High-Energy (UHE) flightweight Lithium-ion (Li-Ion) cells for Extra Vehicular Activity (EVA), Altair Ascent Module and Lunar Surface System customers.   High Energy Cell • Primary technology for Lunar Surface Systems Mobility Systems • Back-up technology for EVA and Altair • Deliver TRL 4 cells by 2012 and TRL 6 cells by September 2013 Ultra-High-Energy Cell • Primary technology for EVA and Altair • Deliver TRL 4 cells by 2013 and TRL 6 cells by Sept. 2014 Approach The ETDP Team developed screening criteria and test plans for the evaluation of the following cell components: anodes, cathodes, separators, electrolyte, and safety functional components. NASA GRC, JSC, and JPL screen the various candidate component materials developed by various sources against the Key Performance Parameters to determine their suitability for the final flightweight cells. Those candidate materials that meet minimum performance requirements are then passed on to the industrial partner. Saft America evaluates the materials for manufacturability, compatibility with the production processing equipment, and scalability to quantities required to build the DD evaluation cells. Saft America scales-up the superior materials from the small laboratory batch sizes into sufficient production level quantities to accommodate the fabrication of the lithium-ion cells. Optimization Saft America performs electrochemical component optimization to enhance the overall safety and performance of the evaluation cells. Based upon modeling relationships and component test data, various component parameters undergo optimization such as electrode substrate, substrate porosity, electrode thickness, active material source, binder and diluent additives, manufacturing methods and material composition impacts, and other cell level design parameters. DD Cell 10 Ah, 34 Wh 124mm L x 34 mm Ø 0.25 kg Hermitically sealed 140 Wh/kg, 325 Wh/L Electroactive Anode Powder (Negative) Electroactive Cathode Powder (Positive) Cathode Material Screening Positive Cathode Ink Mixing Negative Anode Ink Mixing Coating Coating Drying Drying Evaluation Cells Calendaring Calendaring 34P Cell 48 Ah, 176 Wh 120mm H x 152mm L x 25mm W 0.98 kg Hermitically sealed 180 Wh/kg, 385 Wh/L Anode Material Screening Slitting/ Cutting Slitting/ Cutting electrochemistry • Modelling Tools • Spreadsheet-based battery prediction model • Rapidly forecast effect of new materials and cell construction on specific energy • Estimate the effects of porosity, electrode thickness, and irreversible capacity loss • Provides target values for manufacturing lithium-ion components and cells Separator Negative Electrode Winding Stacking Assembly into Container Electrolyte Filling Container Welding Activation/ Formation Characterization Testing • Mission Life Testing Positive Electrode Battery Specific Energy Prediction Summary Significant material evaluations and screenings are necessary to select those candidates that exhibit superior performance and are likely to achieve the performance goals associated with the High Energy and Ultra-High Energy cell designs. Saft America’s evaluation of novel lithium-ion cell components provides insight associated with the manufacturing, electro-chemical compatibility, scale-up to production level quantities, and overall optimization of the lithium-ion cell design. A comparison between the modeling of selected key components (anode, cathode, and electrolyte) and the actual DD Evaluation cell performance provides confidence in determining the optimum cell attributes that lead to fabricating the TRL 6 Flightweight cells. Electrolyte Screening Point of Contact: Tom Miller Email: thomas.b.miller@nasa.gov Phone: 216-433-6300 www.nasa.gov NASA Glenn Research Center – RPC Branch