Battery power requirements in high-performance electric vehicles

International standards and guidelines regarding characterisation and cycle life testing of batteries in electric vehicles (EVs) currently do not take into account high-performance driving. Using simulation software, track driving in a high-performance vehicle is simulated, and speed-time profiles are recorded. These as well as established driving cycles are used in conjunction with an EV model to determine power profiles at battery terminals. The difference in the resulting power profiles suggest that the evaluation of batteries for the HP segment requires separate characterisation and cycle life tests

Electrical and thermal behaviour of pouch-format lithium ion battery cells under high-performance and standard automotive duty-cycles

Six pouch-format cells comprising a carbon anode and nickel-cobalt-manganese (NCM) cathode are characterized. Their 1C discharge capacity and open circuit voltage are determined. Internal Resistance is investigated via Hybrid Pulse Power Characterization tests and Electrochemical Impedance Spectroscopy. They are subsequently subject to two different electrical loading profiles, one representing high-performance (HP) driving applications, the other representing urban and extra-urban driving scenarios. The cells are instrumented with thermocouples to determine their surface temperature during cycling. The experimental results show that HP scenarios result in higher temperatures and temperature gradients, requiring bespoke thermal management strategies and suggesting increased degradation over prolonged use

Breeding Season Distribution of Cerulean Warblers in Arkansas in the 1990s

The Cerulean Warbler (Dendroica cerulea) has been declining in numbers in its North American nesting range, and the same is true in Arkansas. To provide specific sites that can be monitored in the future, this study describes places where the bird was documented in the state in the 1990s. The warbler was found in mature deciduous forest in both upland and bottomland situations but was most abundant in the upland Ozark forests and uncommon in other regions of the state. Most (70%) of the occupied sites were on federal and state lands. Pattern of overall distribution was essentially the same in the 1990s as it was in an earlier period through 1973. Data in one case suggest that group selection type of forest harvest may produce habitats that are beneficial to Cerulean Warblers

Survival and Habitat of Pen-Raised Northern Bobwhites at Camp Robinson Wildlife Demonstration Area, Arkansas (Poster Abstract)

Post-release survival of pen-reared northern bobwhite (Colinus virginianus) is often extremely low. Although predation is usually assumed to cause low survival rates, very little detailed research has been conducted into cause-specific mortality of pen-reared bobwhites in natural settings. Further, little is known about habitat selection by pen-reared bobwhites, and the relationship between habitat and survival. We report results based on 110 radiomarked bobwhites out of 2500 banded and released at Camp Robinson Wildlife Demonstration Area in Arkansas. Birds were released at 125 sites in coveys of 20 birds per site. Release sites were ranked based on habitat quality. In addition, habitat analyses were conducted over each individual’s area of activity. In March 2001, when monitoring of birds ended, 6 birds remained alive. Mortality agents included avian predators (51%, n = 49), mammalian predators (36%, n = 35) and unknown predators (13%, n = 12). Other causes of mortality included radio collars (5%, n = 5) and apparent heat stress (3%, n = 3). Most mortality occurred within 1 month of release (66%, n = 73). Overall mean survival was 36.4 +- 4.3 days. We found no significant difference in length of survival among birds released at good, medium, or poor sites (P = 0.97). Regardless of release site, birds were located most often in shrub cover (50%, n = 388 locations) while the second most common habitat used was herbaceous cover (29%, n = 230 locations). During callback trapping in May 2001, we recaptured 14 bobwhites that were banded and released in August of 2000, and 6 wild birds, suggesting that pen-reared birds actually outnumbered wild birds

Duty-cycle characterisation of large-format automotive lithium ion pouch cells for high performance vehicle applications

The long-term behaviour of lithium ion batteries in high-performance (HP) electric vehicle (EV) applications is not well understood due to a lack of suitable testing cycles and experimental data. As such a generic HP duty cycle (HP-C), representing driving on a race track is validated, and six NMC graphite cells are characterised with respect to cycle-life. To enable a comparison between the HP-EV environment and conventional road driving, two test groups of cells are subject to an experimental evaluation over 200 duty cycles that includes a representative HP-C and a standard duty cycle from the IEC 62660-1 standard (IECC). After testing, both test groups display increased energy capacity, increased pure Ohmic resistance, lower charge transfer resistance an extended OCV operating window. The changes are more pronounced for cells subject to the HP-C. Based on capacity tests, Electrochemical Impedance Spectroscopy (EIS), pseudo-OCV tests, and Pulse Multisine Characterisation, it is concluded that the changes in cell characteristics are most likely caused by cracking of the electrode material caused by high electrical current pulses. With continued cycling, cells cycled with the HP-C are expected to show degradation at an increased rate due to raised temperatures, and more pronounced electrode cracking

Battery cycle life test development for high-performance electric vehicle applications

High Performance (HP) battery electric vehicle (BEV) and racing applications represent significantly different use cases than those associated with conventional consumer vehicles and road driving. The differences between HP use cases and the duty-cycles embodied within established battery test standards will lead to unrepresentative estimates for battery life and performance within a HP application. A strategic requirement exists to define a methodology that may be used to create a representative HP duty-cycle. Within this paper two methods HP duty-cycle design are evaluated and validated. Extensive simulation results into the electrical performance and heat generation within the battery highlight that the new HP duty-cycles provide a more representative duty-cycle compared to traditional battery test standards. The ability to more accurately predict the performance requirements for the battery system within this emerging and strategically important BEV sector will support a range of engineering functions. In addition, the ability to more accurately define the use-case for a HP-BEV will underpin ongoing experimentation and mathematical modelling to quantify the associated cell ageing and degradation that may occur within HP vehicle applications

Digital ethics, political economy and the curriculum: this changes everything

This chapter makes the case for a refocusing of teaching and learning across the curriculum on foundational questions about ethics in digital culture – and, hence, for reframing classroom practice around critical digital literacies. Our view is that a central aim of schooling now should be the interrogation of the forms and contents, practices and consequences of digital communications, and that the curriculum should engage developmentally and systematically with the current issues regarding everyday actions and their consequences, corporate and state surveillance, privacy and transparency, political and economic control and ownershi

Performance benchmarks for scholarly metrics associated with fisheries and wildlife faculty

Research productivity and impact are often considered in professional evaluations of academics, and performance metrics based on publications and citations increasingly are used in such evaluations. To promote evidence-based and informed use of these metrics, we collected publication and citation data for 437 tenure-track faculty members at 33 research-extensive universities in the United States belonging to the National Association of University Fisheries and Wildlife Programs. For each faculty member, we computed 8 commonly used performance metrics based on numbers of publications and citations, and recorded covariates including academic age (time since Ph.D.), sex, percentage of appointment devoted to research, and the sub-disciplinary research focus. Standardized deviance residuals from regression models were used to compare faculty after accounting for variation in performance due to these covariates. We also aggregated residuals to enable comparison across universities. Finally, we tested for temporal trends in citation practices to assess whether the law of constant ratios , used to enable comparison of performance metrics between disciplines that differ in citation and publication practices, applied to fisheries and wildlife sub-disciplines when mapped to Web of Science Journal Citation Report categories. Our regression models reduced deviance by 1/4 to 1/2. Standardized residuals for each faculty member, when combined across metrics as a simple average or weighted via factor analysis, produced similar results in terms of performance based on percentile rankings. Significant variation was observed in scholarly performance across universities, after accounting for the influence of covariates. In contrast to findings for other disciplines, normalized citation ratios for fisheries and wildlife sub-disciplines increased across years. Increases were comparable for all sub-disciplines except ecology. We discuss the advantages and limitations of our methods, illustrate their use when applied to new data, and suggest future improvements. Our benchmarking approach may provide a useful tool to augment detailed, qualitative assessment of performance. © 2016 Swihart et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited