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Kepler, Keith D.

Publications and source records attributed to Kepler, Keith D..

4 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Li-ion pouch cell and a cell module

The present invention provides a Li-ion pouch cell wherein the Li-ion pouch cells comprise a sealed enclosure, electrode stack and thermally conductive elements, wherein the electrode stack and the thermally conductive elements are in the sealed enclosure, the thermally conductive elements include extensions which extend beyond the electrode stack, the sealed enclosure has thermal conductivity, the thermally conductive elements provide a thermally conductive pathway connecting the electrode stack and the sealed enclosure by way of the extension. The present invention also provides a cell module comprising the Li-ion pouch cells. The Li-ion pouch cell and the cell module according to the present application could minimize differences in cell temperature, monitor internal cell temperature, cool the cell rapidly, increase cell and module safety, allowing for minimal impact on cell energy density, performance or life and difficulty of manufacturing.

25 ENERGY STORAGE↗
DOE OSTI2018

High Energy Density Li-ion Cells for EV’s Based on Novel, High Voltage Cathode Material Systems

This Li-ion cell technology development project had three objectives: to develop advanced electrode materials and cell components to enable stable high-voltage operation; to design and demonstrate a Li-ion cell using these materials that meets the PHEV40 performance targets; and to design and demonstrate a Li-ion cell using these materials that meets the EV performance targets. The major challenge to creating stable high energy cells with long cycle life is system integration. Although materials that can give high energy cells are known, stabilizing them towards long-term cycling in the presence of other novel cell components is a major challenge. The major technical barriers addressed by this work include low cathode specific energy, poor electrolyte stability during high voltage operation, and insufficient capacity retention during deep discharge for Si-containing anodes. Through the course of this project, Farasis was able to improve capacity retention of NCM materials for 4.4+ V operation, through both surface treatment and bulk-doping approaches. Other material advances include increased rate capability and of HE-NCM materials through novel synthesis approach, doubling the relative capacity at 1C over materials synthesized using standard methods. Silicon active materials proved challenging throughout the project and ultimately were the limiting factor in the energy density vs. cycle life trade off. By avoiding silicon anodes for the lower energy PHEV design, we manufactured cells with intermediate energy density and long cycle life under high voltage operation for PHEV applications. Cells with high energy density for EV applications were manufactured targeting a 300 Wh/kg design and were able to achieve > 200 cycles.

25 ENERGY STORAGE↗