Summary of the presentations given at the Lithium Mobile Power 2nd edition conference.
Cell Phone Energy Gap: Myth or Reality?
Stuart Robinson, Director, Handset Component Technologies, Strategy Analytics
The demands on a cell phone’s battery just keep growing, with more features and functions being added to each new generation of handset. Drawing upon our end-user research of cell phone usage patterns, combined with analysis of the power consumption trends of critical components, this presentation will highlight some of the key findings from Strategy Analytics’ cell phone battery budget analysis. It tackles two key questions: Where does all the energy go in a cell phone? And, is the cell phone Energy Gap going to grow or shrink in future?
SAFT’s Very High Power Li-Ion Technology
Kamen Nechev, PhD, Senior Scientist/Advanced Technology Manager, Saft Specialty Battery Group, SAFT
SAFT specializes in developing and providing solutions based on Very High Power (VHP) Li-ion. This is an industrial technology capable of 8 kW/kg for 2 second long and 12 kW/kg for millisecond long pulses. SAFT has built and delivered a number of battery systems supporting emerging Directed Energy applications. The VHP technology is also the only electrochemical energy storage system providing sufficient power at low temperature required for aircraft applications. Due to this unique capability it is the heart of the 270V emergency battery for F-35 aircraft.
Powering Robotic Ocean Observing Systems
James G. Bellingham, PhD, Chief Technologist, Monterey Bay Aquarium Research Institute
Mobile robots, capable of operating unattended by humans for days to months at sea, are revolutionizing the way scientists, the military, and the commercial world explore and observe the ocean. Energy storage is a fundamental limitation, and designers of AUVs (Autonomous Underwater Vehicles) go to great lengths to minimize power consumption and maximize energy storage. Reliability and safety are particularly important considerations, as operational conditions at sea are demanding, and vehicles operate at high ambient pressures (up to 9000 psi). This talk will provide an overview of emerging ocean observing systems, their energy needs, and operational requirements.
The Use of Solid Electrolytes to Enable Next Generation High Energy Density Batteries
Steven J. Visco, PhD, Vice President of Research, PolyPlus Battery Company
The introduction of high energy density Li-ion batteries in the early 1990s was timely for the portable electronics industry as battery life was emerging as a key issue for mobile computing and telecommunications. However, it is clear that significant advances in battery technology are needed in order to keep pace with the demands of these industries as well as emerging markets such as hybrid electric vehicles, plug-in hybrids, and electric utility backup. The transition to higher energy battery chemistries will require innovative approaches to do so safely and at reasonable cost. One such approach involves the use of solid electrolyte membranes, either in bulk or thin-film form. This presentation will discuss various strategies of designing next generation technologies (including lithium metal and sodium metal chemistries) based on the unique properties of true solid electrolyte membranes.
Abuse Tolerance Issues for Li-Ion Cells
E. Peter Roth, PhD, Advanced Power Sources R&D Department, Sandia National Laboratories
Li-ion cells are increasingly used in commercial applications ranging from small portable electronic devices to large modules for hybrid-electric vehicles. The new proposed plug-in hybrid vehicles will necessarily incorporate greater levels of stored electrical energy. These cells will therefore have to demonstrate even higher levels of abuse tolerance. We will present the latest safety performance data on several Li-ion chemistries during abuse testing under such conditions as over-temperature and overcharge. We will discuss the fundamental mechanisms affecting abuse tolerance and the future of new cell chemistries.
Safe and Reliable Power Sources for Mission Critical Applications
Robin Sarah Tichy, PhD, Technical Manager, Micro Power Electronics
Catastrophic safety issues - ranging from under-performance to explosions - with battery systems have heightened safety concerns. This presentation will address the common causes of battery system failures, provide design guidelines and techniques for portable device manufacturers, and address the often neglected topic of battery system reliability. The design guidelines cover battery pack authentication technology, over voltage/current protection circuits, recommended charging regimens, battery alternatives and their affiliated volatility. In order to numerically compare the reliability of different topologies, analytic solutions must be derived, based on developed reliability diagrams and established probability density functions. After a review of the issues and industry standards in battery reliability, Micro Power Electronics will present a model and comparison of the reliability of redundant parallel cell strings.
Safety Mechanism for Lithium Polymer Batteries
Markus Pompetzki, PhD, Project Manager R&D, Varta Microbattery GmbH
To guarantee the entire spectrum of the safety requirements all components of the cell have to be chosen carefully and have to be adjusted in a proper way. The separator has to guarantee the safe insulation of the electrodes, also under abusive conditions. Polyolefin separators meet these requirements and provide for a disconnection of the cell via a “shutdown” mechanism before critical temperatures can be reached in the cell. In case of overcharge the safety function of the separator will be maintained by electrolyte additives. These have an inhibitory effect on the reaction between electrolyte and overcharged electrodes and prevent the thermal run-away in the battery. The electrode active materials are also safety relevant. The safety of the cell will be increased, if for example LiCoO2 is replaced by LiNiCoMnO2. *In collaboration with: T.Wöhrle, M.Pompetzki, C.Wurm, P.Haug, and M.Kohlberger
Navy and Marine Corp Lithium Battery Mobile Power Safety
Clinton Winchester, Group Leader & Senior Technologist, Naval Surface Warfare Center (NSWC)
Lithium batteries dominate in Navy and Marine Corps mobile power systems where high energy and high power needs must be balanced by system requirements, risk tolerance, availability, and cost. Lithium battery technologies in fieldable systems are advancing in terms of deployment in new operational environments, the prevalence of larger battery assemblies and a wider variety of lithium chemistries, the use of rechargeable in place of non-rechargeable batteries, and even various hybrid options such as metal-air, battery-capacitor, and battery-solar power. This talk will focus on the safety challenges these lithium battery advancements present for the Navy and the Marine Corps.
Advanced Lithium Ion Super Polymer Batteries for Automotive Applications
Sankar Das Gupta, PhD, Chairman, President & CEO, Electrovaya Inc.
The talk will outline a new advance in technology, where a High Energy density lithium ion polymer battery with energy density of 180 - 210 Wh/kg is used in automotive applications, which needs moderate rates of up to 10C pulses. Applications of this battery in a PHEV (Ford Escape), a battery electric Fleet van (80kWh), a HEV (10kWh) in a small car (30kWh) will be discussed. Safety and performance of these electric vehicles will be analyzed.
Lithium-Ion Batteries as Energy Storage Systems for New Power Trains in Automobiles
Klaus Brandt, PhD, Chief Executive Officer, Lithium Technology Corporation (LTC)
The combustion engine is the power source of today’s automobiles. To date, alternative systems such as electric motors have not been commercially successful. Today’s commercially viable concepts use mixed solutions, which is the Hybrid Electrical Vehicle (HEV). The energy storage system is a major key component in HEVs for an efficient operation. Energy storage systems with better energy and power performance, such as lithium-ion batteries enable enhanced operational characteristics, which will promote mass public adoption for HEV. The presentation describes the performance, the benefit and the feasibility of lithium-ion batteries in hybrid electric vehicles.
Advanced Lithium Ion Technology for PHEV and HEV Applications
Michael E. Reed, President and CEO, Electro Energy Inc.
Electro Energy has successfully demonstrated its bipolar wafer-cell Ni-MH technology through a 220V, 30 Ah, 6 kWh battery system used in a HEV-to-PHEV conversion. A similar system is currently being developed utilizing EEI’s Li-Ion technology, which provides high energy capability, while minimizing wasted space and reducing weight and volume. EEI has recently fabricated and tested Li-Ion cells using new and innovative electrode materials. This presentation provides the test data and demonstrates the capability and advantages of EEI’s Li-Ion technology for HEV and PHEV applications.
High Energy Density Layered Oxide Cathodes for Mobile Applications
Arumugam Manthiram, PhD, Professor, Materials Science and Engineering Program, The University of Texas at Austin
Lithium ion batteries have revolutionized the portable electronics market, but their energy density is limited since only 50% of the theoretical capacity of the currently used layered LiCoO2 cathode can be utilized in practical cells. This presentation will focus on the development of complex layered oxide solid solutions between LiMO2 (M = Mn, Co, and Ni) and Li2MnO3 that exhibit two times higher capacity than the LiCoO2 cathode. The structure-property-performance relationships of these cathodes and the challenges facing them will be discussed.
Thermodynamics and Stability of Cathode Materials for Lithium Ion Batteries
Rachid Yazami, PhD, Director, CNRS-CALTECH International Laboratory on Materials for Electrochemical Energetics, California Institute of Technology
Cathode materials for lithium ion batteries based on transition metal oxides and lithium iron phosphate were investigated by both electrochemical thermodynamics measurements system (ETMS) and by thermal aging at their initial charge state in lithium half cells. The aim is to correlate the observed crystal structure degradation to the thermodynamics data such including the enthalpy and entropy of lithium intercalation and de-intercalation. Most stable materials tend to generate less heat.
Using Nano Processes for Lithium Ion Electrodes
Yevgen Kalynushkin, PhD, Chief Technology Officer, and Kostyantyn Kylyvnyk, NanoEner, Inc.
Li-ion battery performance can be improved dramatically by creating special structures during electrode production. Multi component nano-materials can improve the durability, reliability and safety of modern high-performance Li-ion batteries. A number of companies have successfully used nano-particles in battery electrode production. Li-ion battery performance characteristics can be further improved dramatically by making electrodes with nano processes that produce special structures. We have been able to produce these structures with our proprietary high-pressure deposition-solidification (HDS) technology, which has been tested in the production of negative and positive electrodes. Benefits of our electrode production process:
• eliminates insulating oxide level on the surface of the substrates
• electrodes do not mechanically fail due to defoliation of material substrate
• electrodes are very stable under change of materials volume during cycling
• do not require binding additives
• do not require conductive additives
• provide possibility for extremely high rate of discharge up to 500C
• increase specific characteristics up to 30% high efficiency of deposition
• cost efficient production
Kinetics of the Phase Transition During Discharge of the LiFePO4 Electrode
Jan L. Allen, PhD, Research Chemist, Sensors & Electron Devices Directorate, U.S. Army Research Laboratory
During discharge of a LiFePO4 positive electrode based lithium ion battery, FePO4 is converted to LiFePO4. This electrochemical phase transformation has been investigated by use of kinetic modeling. The analysis gives insight into the dimensionality of the phase transformation and information about the rate determining step which can be useful for design of improved electrodes. Measurements at different temperatures allowed for an estimate of the activation energy for the electrochemical FePO4 to LiFePO4 transformation.
Small Magnetic Polaron Effect in LiFePO4: The Key for Electrochemical Performance in Li-Ion Batteries
Christian M. Julien, PhD, Professor, Institut des Nano-Sciences de Paris, Université Paris
The electronic structure of LiFePO4 and delithiated FePO4 is revisited, in the light of the previous calculations taking into account the Coulomb correlation potential for d-electrons. The nature of the optical transitions across the energy gap is investigated. In LiFePO4, these are intra-atomic Fe2+-Fe3+ transitions suffering a strong Franck-Condon effect due to the local distortion of the lattice in FePO4, which an indirect evidence of the formation of small polaron. This is at contrast with the situation met in the much more covalent delithiated phase where the optical transition across the energy gap is associated to a transfer of electron from the p-states of the oxygen and the d-states of iron ions. The small polarons in LiFePO4 are associated to the presence of Fe3+ ions introduced by native defects in relative concentration [Fe3+]/[Fe2++Fe3+] = 3x10-3 in the samples known to be optimized with respect to their electrochemical properties. The nearest iron neighbours around the central polaron site are spin-polarized by the indirect exchange mediated by the electronic charge in excess. These small magnetic polarons are responsible for the interplay between electronic and magnetic properties that are quantitatively and self-consistently analyzed. *In collaboration with: A.Mauger, CNRS and F.Gendron, Université Paris6
Routes to Improve Lithium Iron Phosphate for Battery Applications
Margret Wohlfahrt-Mehrens, PhD, ZSW - Zentrum für Sonnenenergie- und Wasserstoff-Forschung
Lithium iron phosphate is a very attractive alternative cathode material for high power lithium ion batteries. This material exhibits advantages in terms of low raw material costs, long cycle and calendar life and excellent safety characteristics. Many efforts have been made to enhance the rate capability of LiFePO4 by designing nano-particle or nano-structured materials, by coating with carbon or by doping the LiFePO4. Recently, high power lithium ion batteries with LiFePO4 as cathode material have been introduced to the market. The electrochemical performance depends significantly on the synthesis parameters and on the surface coating. In this study we discuss various routes to improve LiFePO4 and their impact on power and life performance.
Chemical and Electrochemical Reactivity of Intermediate LixFePO4 Phases
Thomas J. Richardson, PhD, Staff Scientist, Environmental Energy Technologies Division, Lawrence Berkeley National Laboratory
The role of intermediate phases in the interconversion of LiFePO4 and FePO4 has been a subject of considerable controversy. Although well-defined single phase solid solutions exist at elevated temperatures for all values of X, non-stoichiometry near the end members at room temperature has been seen in some samples and not in others. The results of a systematic investigation of the structures and reactivity of intermediate olivine phase will be presented.
Large Format Li-ion cells with LiFePO4 Cathode Material
Kamen Nechev, PhD, Senior Scientist/Advanced Technology Manager, Saft Specialty Battery Group, SAFT
SAFT has developed LiFePO4 technology for its defense markets. So far two cell sizes have been built and tested - 10 Ah and 25 Ah. It is well known to everyone in the battery community that large cells do not behave the same as small cells. The performance of these fairly large cells in terms of specific energy, power and life will be described. Comparisons with other standard Li-ion chemistries will be made. Behavior under abuse conditions will also be discussed.