On the coupled thermo–electro–chemo–mechanical performance of structural batteries with emphasis on thermal effects

Carbon fibre (CF) based structural batteries is a type of battery designed to sustain mechanical loads. In this paper, a fully coupled thermo–electro–chemo–mechanical computational modelling framework for CF based structural batteries is presented. We consider the combined effects of lithium insertion in the carbon fibres leading to insertion strains, and thermal expansion/shrinkage of the constituents leading to thermal (free) strains, while assuming transverse isotropy. The numerical studies show that the developed framework is able to capture the coupled thermo–electro–chemo–mechanical behaviour. Moreover, it is found that the dominating source for heat generation during galvanostatic cycling is associated with discontinuities in the electrical and chemical potentials at the fibre/electrolyte interface. Further, a limited parameter study shows that the temperature change during electrochemical cycling is significantly influenced by the applied current, thermal properties of the constituents and heat exchange with the surroundings. Finally, for large temperature variations, e.g. as identified during relevant (dis)charge conditions, the magnitude of the thermal strains in the structural battery electrolyte (SBE) are found to be similar to the insertion induced strains

Electro-chemo-mechanically coupled computational modelling of structural batteries

Structural batteries are multifunctional composites that combine load-bearing capacity with electro-chemical energy storage capability. The laminated architecture is considered in this paper, whereby restriction is made to a so called half-cell in order to focus on the main characteristics and provide a computational tool for future parameter studies. A thermodynamically consistent modelling approach is exploited for the relevant electro-chemo-mechanical system. We consider effects of lithium insertion in the carbon fibres, leading to insertion strains, while assuming transverse isotropy. Further, stress-assisted ionic transport is accounted for in addition to standard diffusion and migration. The relevant space-variational problems that result from time discretisation are established and evaluated in some detail. The proposed model framework is applied to a generic/idealized material representation to demonstrate its functionality and the importance of accounting for the electro-chemo-mechanical coupling effects. As a proof of concept, the numerical studies reveal that it is vital to account for two-way coupling in order to predict the multifunctional (i.e. combined electro-chemo-mechanical) performance of structural batteries

Unit cells for multiphysics modelling of structural battery composites

To predict the multifunctional performance of structural battery composites, multiple physical phenomena need to be studied simultaneously. Hence, multiphysics models are needed to evaluate the complete performance of this composite material. In this study the coupled analysis for multiphysics modelling of structural battery composites is presented and modelling strategies and unit cell designs are discussed with respect to the different physical models. Furthermore, FE-models are setup in the commercial Finite Element (FE) software COMSOL to study if existing physics-based modelling techniques and homogenization schemes for conventional lithium ion batteries can be used to describe the electrochemical behaviour of structural battery composites. To predict the microscopic behaviour, the local variation of the mass and charge concentrations need to be accounted for. Hence, refined models with appropriate boundary conditions are needed to capture the microscopic conditions inside the material. The numerical results demonstrate that conventional physics-based 1D battery models and homogenization schemes based on porous media theory can be used to predict the macroscopic electrical behaviour of the fibrous structural battery. For future work electrochemical experiments on battery cell level are planned to validate the numerical results

Variationally consistent modeling of a sensor-actuator based on shape-morphing from electro-chemical–mechanical interactions

This paper concerns the computational modeling of a class of carbon fiber composites, known as shape-morphing and strain-sensing composites. The actuating and sensing performance of such (smart) materials is achieved by the interplay between electrochemistry and mechanics, in particular the ability of carbon fibers to (de)intercalate Li-ions repeatedly. We focus on the actuation and sensing properties of a beam in conjunction with the appropriate “through-the-thickness” properties. Thus, the electro-chemo-mechanical analysis is essentially two-dimensional, and it is possible to rely heavily on the results in Carlstedt et al. (2020). More specifically, the cross-sectional design is composed of two electrodes, consisting of (partly) lithiated carbon fibers embedded in structural battery electrolyte (SBE), on either side of a separator. As a result, the modeling is hierarchical in the sense that (macroscale) beam action is combined with electro-chemo-mechanical interaction along the beam. The setup is able to work as sensor or actuator depending on the choice of control (and response) variables. Although quite idealized, this design allows for a qualitative investigation. In this paper we demonstrate the capability of the developed framework to simulate both the actuator and sensor modes. As proof of concept, we show that both modes of functionality can be captured using the developed framework. For the actuator mode, the predicted deformation is found to be in close agreement with experimental data. Further, the sensor-mode is found to agree with experimental data available in the literature

Integrated Risk Management - från teori till praktik

Bakgrundsbeskrivning: Traditionellt har risk betraktats som något negativt och olika typer av risker har hanterats av olika funktioner. Sedan ett antal år har Integrated Risk Management (IRM) utvecklats som koncept för riskhantering. IRM innebär samordning och integration av riskhanteringsarbetet. Problemställning: I vissa länder har lagstiftning tvingat företag att implementera system som IRM, men det råder fortfarande viss oklarhet i vilka motiven och effekterna är. Vi frågar oss därför vilka anledningar det finns att använda IRM? Vad är målsättningen och motiven? Vilket värde (effekter) skapar det egentligen för företaget? Vidare saknas det studier i vad IRM innebär i praktiken, särskilt erfarenheter från nordiska företag. Vad är det som ska utvecklas och installeras? Vilka mätmetoder är lämpliga i riskanalysen? Avslutningsvis rådet det oklarhet kring vilka krav IRM ställer på företaget? Bland pionjärerna i Sverige återfinns företaget Sydkraft Företaget har givit oss i uppdrag att föreslå ett antal rekommendationer för vidarutveckling av företagets IRMprogram. Syfte: Syftet har varit att beskriva och analysera IRM vad det gäller utveckling, teori och praktik samt utreda och utveckla Sydkrafts IRM Metod: Tre delstudier har genomförts. En teoristudie, en referensstudie med konsulter och fyra fallföretag samt huvudfallstudien som är inriktad på Sydkraft. Studien har en kvalitativ, explorativ ansatts. Resultat: Att mäta effekterna av IRM genom ett totalt riskmått är inte möjligt då alla risker är olika. Därför är det svårt att mäta effekten av IRM på samma sätt som kan låta sig göras med traditionell risk management. Grundproblematiken med ett arbetssätt som IRM handlar om att människor uppfattar risk på olika sätt. Därför skapar IRM värde för en organisation främst genom att öka riskmedvetenheten. För att IRM överhuvudtaget ska kunna förankras i en organisation bör en CRO och en riskkommité inrättas. Den senare bör ha en exekutiv roll, även om den i nordiska företag verkar ha en mer rådgivande funktion. Vidare visar studien att riskrapportering skiljer sig från traditionell ekonomi- och verksamhetsstyrning då den även omfattar risker (händelser) som inte ingår i budgeten

Computational modelling of structural batteries accounting for stress-assisted convection in the electrolyte

Structural batteries consist of carbon fibres embedded in a porous structural battery electrolyte (SBE), which is composed of two continuous phases: a solid polymer skeleton and a liquid electrolyte containing Li-salt. In this paper we elaborate on a computational modelling framework to study the electro-chemo-mechanical properties of such structural batteries while accounting for the combined action from migration as well as stress-assisted diffusion and convection in the electrolyte. Further, we consider effects of lithium insertion in the carbon fibres, leading to insertion strains. The focus is placed on how the convective contribution to the mass transport within the SBE affects the general electro-chemo-mechanical properties. The numerical results indicate that the convective contribution has only minor influence on the multifunctional performance when the mechanical loading is caused by constrained deformation of constituents during electro-chemical cycling. However, in the case of externally applied mechanical loading that causes severe deformation of the SBE, or when large current pulses are applied, the convective contribution has noticeable influence on the electro-chemical performance. In addition, it is shown that the porosity of the SBE, which affects the effective stiffness as well as the mobility and permeability, has significant influence on the combined mechanical and electro-chemical performance

Prenatal phthalate exposures and anogenital distance in Swedish boys

BACKGROUND: Phthalates are used as plasticizers in soft polyvinyl chloride (PVC) and in a large number of consumer products. Because of reported health risks, diisononyl phthalate (DiNP) has been introduced as a replacement for di(2-ethylhexyl) phthalate (DEHP) in soft PVC. This raises concerns because animal data suggest that DiNP may have antiandrogenic properties similar to those of DEHP. The anogenital distance (AGD)-the distance from the anus to the genitals-has been used to assess reproductive toxicity. OBJECTIVE: The objective of this study was to examine the associations between prenatal phthalate exposure and AGD in Swedish infants. METHODS: AGD was measured in 196 boys at 21 months of age, and first-trimester urine was analyzed for 10 phthalate metabolites of DEP (diethyl phthalate), DBP (dibutyl phthalate), DEHP, BBzP (benzylbutyl phthalate), as well as DiNP and creatinine. Data on covariates were collected by questionnaires. RESULTS: The most significant associations were found between the shorter of two AGD measures (anoscrotal distance; AGDas) and DiNP metabolites and strongest for oh-MMeOP [mono(4-methyl-7-hydroxyloctyl) phthalate] and oxo-MMeOP [mono-(2-ethyl-5-oxohexyl) phthalate]. However, the AGDas reduction was small (4%) in relation to more than an interquartile range increase in DiNP exposure. CONCLUSIONS: These findings call into question the safety of substituting DiNP for DEHP in soft PVC, particularly because a shorter male AGD has been shown to relate to male genital birth defects in children and impaired reproductive function in adult males and the fact that human levels of DiNP are increasing globally

Exhaled nitric oxide and urinary EPX levels in infants: a pilot study

<p>Abstract</p> <p>Background</p> <p>Objective markers of early airway inflammation in infants are not established but are of great interest in a scientific setting. Exhaled nitric oxide (FeNO) and urinary eosinophilic protein X (uEPX) are a two such interesting markers.</p> <p>Objective</p> <p>To investigate the feasibility of measuring FeNO and uEPX in infants and their mothers and to determine if any relations between these two variables and environmental factors can be seen in a small sample size. This was conducted as a pilot study for the ongoing Swedish Environmental Longitudinal Mother and child Asthma and allergy study (SELMA).</p> <p>Methods</p> <p>Consecutive infants between two and six months old and their mothers at children's health care centres were invited, and 110 mother-infant pairs participated. FeNO and uEPX were analysed in both mothers and infants. FeNO was analyzed in the mothers online by the use of the handheld Niox Mino device and in the infants offline from exhaled air sampled during tidal breathing. A 33-question multiple-choice questionnaire that dealt with symptoms of allergic disease, heredity, and housing characteristics was used.</p> <p>Results</p> <p>FeNO levels were reduced in infants with a history of upper respiratory symptoms during the previous two weeks (p < 0.002). There was a trend towards higher FeNO levels in infants with windowpane condensation in the home (p < 0.05). There was no association between uEPX in the infants and the other studied variables.</p> <p>Conclusion</p> <p>The use of uEPX as a marker of early inflammation was not supported. FeNO levels in infants were associated to windowpane condensation. Measuring FeNO by the present method may be an interesting way of evaluating early airway inflammation. In a major population study, however, the method is difficult to use, for practical reasons.</p

Outsourcing-"kostar det något att ta hissen"

Outsourcing är idag ett väldebatterat strategiskt verktyg, vilket används inom många olika områden och har ett stort antal motiv. Den ökade populariteten för utkontraktering som strategiskt handlingsalternativ bland svenska företagsledare kan härledas till de olika motiv som finns presenterade i diverse litteratur, artiklar, uppsatser och avhandlingar. Genom att använda sig av outsourcing kan företag uppnå en rad positiva och negativa effekter. Vi har i denna uppsats använt oss av en kvalitativ undersökning baserad på fyra fallföretag. I vårt arbete har vi kommit fram till att det inte finns några större skillnader mellan de motiv litteraturen beskriver och de motiv våra fallföretag har haft till att lägga ut en verksamhet på en extern leverantör. Det vi däremot menar att vi kan påvisa genom vår undersökning är att företag kan lägga ut taktiska verksamheter för att uppnå strategiska effekter. De bieffekter vi har kunnat identifiera genom att analysera genomförandet av fallföretagens utkontrakteringar är dels en ökad kostnadsmedvetenhet bland personalen och dels att resurser frigörs genom en minskad leverantörsbas. Anledningen till att personalen blir mer kostnadsmedveten när en verksamhet outsourcas till en extern leverantör är att debiteringsprocessen förändras

PVC flooring is related to human uptake of phthalates in infants.

Poly Vinyl Chloride (PVC) flooring material contains phthalates and it has been shown that such materials are important sources for phthalates in indoor dust. Phthalates are suspected endocrine disrupting chemicals (EDCs). Consecutive infants between two and six months old and their mothers were invited. A questionnaire about indoor environmental factors and family life style was used. Urinary metabolites of the phthalates di-ethyl phthalate (DEP), di-butyl phthalate (DBP), butylbenzyl phthalate (BBzP) and di-etylhexyl phthalate (DEHP) were measured in the urine of the children. Of 209 invited children, 110 (52%) participated. Urine samples were obtained from 83 of these. Urine levels of the BBzP metabolite monobenzyl phthalate (MBzP) was significantly higher in infants with PVC flooring in their bedrooms (p<0.007) and related to the body area of the infant. Levels of the DEHP metabolites MEHHP (p<0.01) and MEOHP (p<0.04) were higher in the two months old infants who were not exclusively breastfed when compared with breastfed children. The findings indicate that the use of soft PVC as flooring material may increase the human uptake of phthalates in infants. Urinary levels of phthalate metabolites during early life are associated to the use of PVC flooring in the bedroom, body area and the use of infant formula. © 2012 John Wiley & Sons A/S