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  • 1.
    Bessman, Alexander
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Soares, Rúdi
    KTH, Skolan för elektro- och systemteknik (EES), Elkraftteknik.
    Vadivelu, Sunilkumar
    KTH, Skolan för elektro- och systemteknik (EES), Elkraftteknik.
    Wallmark, Oskar
    KTH, Skolan för elektro- och systemteknik (EES), Elkraftteknik.
    Svens, Pontus
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Ekström, Henrik
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Lindbergh, Göran
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Challenging Sinusoidal Ripple-Current Charging of Lithium-Ion Batteries2018Inngår i: IEEE transactions on industrial electronics (1982. Print), ISSN 0278-0046, E-ISSN 1557-9948, Vol. 65, nr 6, s. 4750-4757Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Sinusoidal ripple-current charging has previously been reported to increase both charging efficiency and energy efficiency and decrease charging time when used to charge lithium-ion battery cells. In this paper, we show that no such effect exists in lithium-ion battery cells, based on an experimental study of large-size prismatic cells. Additionally, we use a physics-based model to show that no such effect should exist, based on the underlying electrochemical principles.

  • 2.
    Bessman, Alexander
    et al.
    KTH.
    Soares, Rúdi
    KTH.
    Wallmark, Oskar
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg.
    Svens, Pontus
    KTH.
    Lindbergh, Göran
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Aging effects of AC harmonics on lithium-ion cellsManuskript (preprint) (Annet vitenskapelig)
  • 3.
    Bessman, Alexander
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Soares, Rúdi
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Wallmark, Oskar
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Svens, Pontus
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Lindbergh, Göran
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Aging effects of AC harmonics on lithium-ion cells2019Inngår i: Journal of Energy Storage, E-ISSN 2352-152X, Vol. 21, s. 741-749Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    With the vehicle industry poised to take the step into the era of electric vehicles, concerns have been raised that AC harmonics arising from switching of power electronics and harmonics in electric machinery may damage the battery. In light of this, we have studied the effect of several different frequencies on the aging of 28 Ah commercial NMC/graphite prismatic lithium-ion battery cells. The tested frequencies are 1 Hz, 100 Hz, and 1 kHz, all with a peak amplitude of 21 A. Both the effect on cycled cells and calendar aged cells is tested. The cycled cells are cycled at a rate of 1C:1C, i.e., 28 A during both charging and discharging, with the exception of a period of constant voltage at the end of every charge. After running for one year, the cycled cells have completed approximately 2000 cycles. The cells are characterized periodically to follow how their capacities and power capabilities evolve. After completion of the test about 80% of the initial capacity remained and no increase in resistance was observed. No negative effect on either capacity fade or power fade is observed in this study, and no difference in aging mechanism is detected when using non-invasive electrochemical methods of post mortem investigation.

  • 4.
    Klass, Verena
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Svens, Pontus
    Scania CV AB.
    Behm, Mårten
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Lindbergh, Göran
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    State-of-health estimation of lithium-ion battery under emulated HEV operation on board heavy-duty truckManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    This paper addresses the need for simple and cost-effective methods that detect the state-of-health (SOH) of batteries in vehicle applications solely based on data readily available from the battery management system without any knowledge of battery properties, prior laboratory measurements or additional equipment.

    A power-optimized lithium-ion battery cell is operated in an emulated hybrid electric vehicle (HEV) environment on board a conventional heavy-duty truck. The HEV operation of the battery cell depends on the driving pattern of the truck within set limits. Beyond the HEV operation, the performance of the battery cell is periodically measured with on-board standard pulse and capacity tests. On basis of the battery operating data collected in the field test, support vector machine-based battery models are built. From a model input of current, temperature, state-of-charge, and current history, the model accurately estimates the battery voltage despite the tough HEV operating conditions with high current pulses. This data-driven battery model is used to estimate the battery cell’s charge and discharge resistance as well as capacity, i.e. the performance measures verified with the standard tests. These SOH indicators can be predicted by the model with adequate accuracy for on-board SOH detection and are followed throughout the one-year field test period.

  • 5.
    Klett, Matilda
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Eriksson, Rickard
    Uppsala University.
    Groot, Jens
    Chalmers Technical University.
    Svens, Pontus
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Ciosek Högström, Katarzyna
    Uppsala University.
    Wreland Lindström, Rakel
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Berg, Helena
    Gustafson, Torbjörn
    Uppsala University.
    Lindbergh, Göran
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Edström, Kristina
    Uppsala University.
    Non-uniform aging of cycled commercial LiFePO4//graphite cylindrical cells revealed by post-mortem analysis2014Inngår i: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 257, s. 126-137Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Aging of power-optimized commercial 2.3 Ah cylindrical LiFePO4//graphite cells to be used in hybrid electric vehicle is investigated and compared for three different aging procedures; (i) using a simulated hybrid electric vehicle cycle within a narrow SOC-range, (ii) using a constant-current cycle over a 100% SOC-range, and (iii) stored during three years at 22 degrees C. Postmortem analysis of the cells is performed after full-cell electrochemical characterization and discharge. EIS and capacity measurements are made on different parts of the disassembled cells. Material characterization includes SEM, EDX, HAXPES/XPS and XRD. The most remarkable result is that both cycled cells displayed highly uneven aging primarily of the graphite electrodes, showing large differences between the central parts of the jellyroll compared to the outer parts. The aging variations are identified as differences in capacity and impedance of the graphite electrode, associated with different SEI characteristics. Loss of cyclable lithium is mirrored by a varying degree of lithiation in the positive electrode and electrode slippage. The spatial variation in negative electrode degradation and utilization observed is most likely connected to gradients in temperature and pressure, that can give rise to current density and potential distributions within the jellyroll during cycling.

  • 6.
    Klett, Matilda
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Svens, Pontus
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Tengstedt, Carl
    Scania CV AB.
    Swiatowska, Jolanta
    Institute de Recherche de Chimie Paris, CNRS- Chimie ParisTech.
    Seyeux, Antoine
    Institute de Recherche de Chimie Paris, CNRS- Chimie ParisTech.
    Lindbergh, Göran
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Wreland Lindström, Rakel
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Uneven film formation across depth of porous graphite electrodes from cycling in commercial Li-ion batteriesManuskript (preprint) (Annet vitenskapelig)
  • 7.
    Mussa, Abdilbari
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Liivat, Anti
    Uppsala Univ, Angstrom Lab, Dept Chem, Box 538, SE-75121 Uppsala, Sweden..
    Marzano, Fernanda
    Uppsala Univ, Angstrom Lab, Dept Chem, Box 538, SE-75121 Uppsala, Sweden.;Scania CV AB, SE-15187 Sodertalje, Sweden..
    Klett, Matilda
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi. Scania CV AB, SE-15187 Sodertalje, Sweden.
    Philippe, Bertrand
    Uppsala Univ, Dept Phys & Astron, Mol & Condensed Matter Phys, Box 516, S-75120 Uppsala, Sweden..
    Tengstedt, Carl
    Scania CV AB, SE-15187 Sodertalje, Sweden..
    Lindbergh, Göran
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Edstrom, Kristina
    Uppsala Univ, Angstrom Lab, Dept Chem, Box 538, SE-75121 Uppsala, Sweden..
    Lindström, Rakel Wreland
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Svens, Pontus
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi. Scania CV AB, SE-15187 Sodertalje, Sweden.
    Fast-charging effects on ageing for energy-optimized automotive LiNi1/3Mn1/3Co1/3O2/graphite prismatic lithium-ion cells2019Inngår i: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 422, s. 175-184Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The reactions in energy-optimized 25 Ah prismatic NMC/graphite lithium-ion cell, as a function of fast charging (1C-4C), are more complex than earlier described. There are no clear charging rate dependent trends but rather different mechanisms dominating at the different charging rates. Ageing processes are faster at 3 and 4C charging. Cycling with 3C-charging results in accelerated lithium plating but the 4C-charging results in extensive gas evolution that contribute significantly to the large cell impedance rise. Graphite exfoliation and accelerated lithium inventory loss point to the graphite electrode as the source of the gas evolution. The results are based on careful post-mortem analyses of electrodes using: scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and electrochemical impedance spectroscopy (EIS). SEM results show particle cracking independent of the charging rate used for the cycling. XPS and EIS generally indicate thicker surface film and larger impedance, respectively, towards the edge of the jellyrolls. For the intended application of a battery electric inner-city bus using this type of cell, charging rates of 3C and above are not feasible, considering battery lifetime. However, charging rates of 2C and below are too slow from the point of view of practical charging time.

  • 8.
    Soares, Rudi
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Bessman, Alexander
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Wallmark, Oskar
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Leksell, Mats
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Behm, Mårten
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Svens, Pontus
    Design Aspects of an Experimental Setup for Investigating Current Ripple Effects in Lithium-ion Battery Cells2015Inngår i: Power Electronics and Applications (EPE'15 ECCE-Europe), 2015 17th European Conference on, IEEE conference proceedings, 2015, s. 1-8Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper describes an experimental setup for investigating the effects of current ripple on lithium-ion battery cells. The experimental setup is designed so that twelve li-ion cells can be simultaneously tested in a controlled environment. The experimental setup allows for a wide range of current ripple in terms of frequency and amplitude. Additionally, the quantification of the current ripple effects such as the aging of li-ion cells implies that a precise measurement system has to be designed which also are discussed in the paper.

  • 9.
    Soares, Rudi
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik. KTH.
    Bessman, Alexander
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH).
    Wallmark, Oskar
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg.
    Lindbergh, Göran
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Svens, Pontus
    Scania.
    An Experimental Setup with Alternating Current Capability for Evaluating Large Lithium-Ion Battery Cells2018Inngår i: Batteries-Basel, ISSN 2313-0105, Vol. 4, nr 3, artikkel-id 38Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In the majority of applications using lithium-ion batteries, batteries are exposed to some harmonic content apart from the main charging/discharging current. The understanding of the effects that alternating currents have on batteries requires specific characterization methods and accurate measurement equipment. The lack of commercial battery testers with high alternating current capability simultaneously to the ability of operating at frequencies above 200 Hz, led to the design of the presented experimental setup. Additionally, the experimental setup expands the state-of-the-art of lithium-ion batteries testers by incorporating relevant lithium-ion battery cell characterization routines, namely hybrid pulse power current, incremental capacity analysis and galvanic intermittent titration technique. In this paper the hardware and the measurement capabilities of the experimental setup are presented. Moreover, the measurements errors due to the setup’s instruments were analysed to ensure lithium-ion batteries cell characterization quality. Finally, this paper presents preliminary results of capacity fade tests where 28 Ah cells were cycled with and without the injection of 21 A alternating at 1 kHz. Up to 300 cycles, no significant fade in cell capacity may be measured, meaning that alternating currents may not be as harmful for lithium-ion batteries as considered so far.

  • 10.
    Soares, Rúdi
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik. KTH.
    Wallmark, Oskar
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg. KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Lindbergh, Göran ()
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Svens, Pontus ()
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Analysis and Prediction of the Harmonic Content in the Battery Currentof a Commercial Hybrid-Electric BusInngår i: IEEE Transactions on Transportation ElectrificationArtikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents a comparison of the harmoniccontent in the battery current in two, commercialhybrid electric vehicles (HEVs) (intercity passenger buses)when operated in realistic drive scenarios. These harmonicscan contribute to issues related to electromagnetic compatibilityand indirectly accelerate the aging of the battery dueto elevated cell temperatures caused by associated ohmiclosses. A key finding is that low-frequency harmonics (upto approximately 130 Hz) attributed to resolver eccentricityand non-ideal effects in the voltage-source inverter (VSI) (upto approximately 260 Hz) were significant in terms of magnitudes.Also, the variation between the two HEVs (in termsof current magnitude) were substantial for these harmonics.This is an important observation since it demonstratesthat significant, low-frequency harmonics can be presentin the battery current and that modeling and collectingexperimental data from a single corresponding vehicle maynot sufficiently represent the harmonic content in the batterycurrent for a fleet of vehicles.

  • 11.
    Soares, Rúdi
    et al.
    KTH.
    Bessman, Alexander
    KTH.
    Wallmark, Oskar
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg.
    Lindbergh, Göran
    KTH.
    Svens, Pontus
    KTH.
    A Control Method for Battery Heating Using Alternating CurrentManuskript (preprint) (Annet vitenskapelig)
  • 12.
    Soares, Rúdi
    et al.
    KTH.
    Bessman, Alexander
    KTH.
    Wallmark, Oskar
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg.
    Lindbergh, Göran
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Svens, Pontus
    KTH.
    An Experimental Setup with Alternating Current Capability for Evaluating Large Lithium-ion Batteries CellsManuskript (preprint) (Annet vitenskapelig)
  • 13.
    Svens, Pontus
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Development of a Novel Method for Lithium-Ion Battery Testing on Heavy-Duty Vehicles2011Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Increasing demands for lower environmental impact from vehicles, including heavy-duty vehicles, have driven several vehicle manufacturers to consider adding hybrid electrical vehicles (HEV’s) to the product portfolio. Present research on batteries for HEV’s is mainly focused on lithium-ion battery chemistries, since lithium-ion batteries has the most promising technical potential compared to other types of batteries. However, the uncertainty regarding battery lifetime combined with a high battery cost can have a negative impact on large scale commercialisation of heavy-duty hybrid vehicles in the near future.

    A large part of present lithium-ion battery research is focused on new materials, but there is also research focusing on ageing of already established lithium-ion battery chemistries. Cycle ageing of batteries often includes complete charging and discharging of batteries or the use of standardized test cycles. Battery cycling in real HEV applications is however quite different compared to this kind of laboratory testing, and real life testing on vehicles is a way of verifying the soundness of laboratory ageing.

    The aim of this study was to develop a test method suitable for real life testing of lithium-ion batteries for heavy-duty HEV-usage, with the purpose of investigating the correlation of battery ageing and usage in real life applications. This concept study includes both cell level battery cycling and performance testing on board vehicles. The performance tests consist of discharge capacity measurements and hybrid pulse power characterization (HPPC) tests. The main feature of this test equipment is that it is designed to be used on conventional vehicles, emulating an HEV environment for the tested battery. The functionality of the equipment was verified on a heavy-duty HEV with satisfying results. Results from real life testing of 8 batteries using the developed test equipment on four conventional heavy-duty trucks shows that the concept of comparing battery ageing with battery usage has a most promising potential to be used as a tool when optimizing battery usage vs. lifetime. Initial results from this real life study shows significant differences in state of charge (SOC) and power distributions between cycled batteries, but so far only small differences in ageing. Lithium-ion batteries of the type lithium manganese spinel/lithium titanate (LMO/LTO) were used in this study.

  • 14.
    Svens, Pontus
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Methods for Testing and Analyzing Lithium-Ion Battery Cells intended for Heavy-Duty Hybrid Electric Vehicles2014Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Lithium-ion batteries designed for use in heavy-duty hybrid vehicles are continuously improved in terms of performance and longevity, but they still have limitations that need to be considered when developing new hybrid vehicles.               

    The aim of this thesis has been to study and evaluate potential test and analysis methods suitable for being used in the design process when maximizing lifetime and utilization of batteries in heavy-duty hybrid vehicles.

    A concept for battery cell cycling on vehicles has been evaluated. The work included development of test equipment, verification of hardware and software as well as an extended period of validation on heavy-duty trucks. The work showed that the concept has great potential for evaluating strategies for battery usage in hybrid vehicles, but is less useful for accelerated aging of battery cells.                            

    Battery cells encapsulated in flexible packaging material have been investigated with respect to the durability of the encapsulation in a demanding heavy-duty hybrid truck environment. No effect on water intrusion was detected after vibration and temperature cycling of the battery cells.                   

    Aging of commercial battery cells of the type lithium manganese oxide - lithium cobalt oxide / lithium titanium oxide (LMO-LCO/LTO) was investigated with different electrochemical methods to gain a deeper understanding of the origin of performance deterioration, and to understand the consequences of aging from a vehicle manufacturer's perspective. The investigation revealed that both capacity loss and impedance rise were largely linked to the positive electrode for this type of battery chemistry.                          

    Postmortem analysis of material from cycle-aged and calendar-aged battery cells of the type LMO-LCO/LTO and LiFePO4/graphite was performed to reveal details about aging mechanisms for those cell chemistries. Analysis of cycle-aged LMO-LCO/LTO cells revealed traces of manganese in the negative electrode and that the positive electrode exhibited the most severe aging. Analysis of cycle-aged LFP/graphite cells revealed traces of iron in the negative electrode and that the negative electrode exhibited the most severe aging.

  • 15.
    Svens, Pontus
    et al.
    Scania CV AB, Sweden.
    Behm, Mårten
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Lindbergh, Göran
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Lithium-Ion Battery Cell Cycling and Usage Analysis in a Heavy-Duty Truck Field Study2015Inngår i: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 8, nr 5, s. 4513-4528Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents results from a field test performed on commercial power-optimized lithium-ion battery cells cycled on three heavy-duty trucks. The goal with this study was to age battery cells in a hybrid electric vehicle (HEV) environment and find suitable methods for identifying cell ageing. The battery cells were cycled on in-house developed equipment intended for testing on conventional vehicles by emulating an HEV environment. A hybrid strategy that allows battery usage to vary within certain limits depending on driving patterns was used. This concept allows unobtrusive and low-cost testing of battery cells under realistic conditions. Each truck was equipped with one cell cycling equipment and two battery cells. One cell per vehicle was cycled during the test period while a reference cell on each vehicle experienced the same environmental conditions without being cycled. Differential voltage analysis and electrochemical impedance spectroscopy were used to identify ageing of the tested battery cells. Analysis of driving patterns and battery usage was performed from collected vehicle data and battery cell data.

  • 16.
    Svens, Pontus
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Eriksson, Rickard
    Uppsala University.
    Hansson, Jörgen
    Behm, Mårten
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Gustafson, Torbjörn
    Uppsala University.
    Lindbergh, Göran
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Analysis of ageing of commercial composite metal oxide: Li4Ti5O12 battery cellsManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Commercial battery cells with Li4Ti5O12 negative electrode and composite metal oxidepositive electrode have been analyzed with respect to ageing mechanisms. Electrochemical impedancespectroscopy (EIS), differential capacity analysis (dQ/dV), differential voltage analysis (dV/dQ) andscanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDX) were used to identifydifferent ageing mechanisms such as lithium inventory loss, loss of active electrode material andsurface film growth. The active material of the positive electrode was also examined by X-raydiffraction (XRD). Ageing mechanisms were studied for both calendar-aged and cycle-aged cells. Datafrom half cells prepared from post mortem harvested electrode material, using lithium foil as negativeelectrode and pouch material as encapsulation, were used as reference to full cell data. Electrochemicalanalysis of full and half cells combined with material analysis showed to be a powerful method toidentify ageing mechanisms in this type of commercial cells. The calendar-aged cell showedinsignificant ageing while the cycle-aged cell showed noticeable loss of positive electrode activematerial and loss of cyclable lithium, but only minor loss of negative electrode active material. Theresults imply that Li4Ti5O12 negative electrode material is a good alternative to other materials if highenergy density is not the primary goal.

  • 17.
    Svens, Pontus
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Hellqvist Kjell, Maria
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Tengstedt, Carl
    Flodberg, Göran
    Lindbergh, Göran
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Li-Ion Pouch Cells for Vehicle Applications-Studies of Water Transmission and Packing Materials2013Inngår i: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 6, nr 1, s. 400-410Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study includes analysis of encapsulation materials from lithium-ion pouch cells and water vapour transmission rate (WVTR) measurements. WVTR measurements are performed on both fresh and environmentally stressed lithium-ion pouch cells. Capacity measurements are performed on both the fresh and the environmentally stressed battery cells to identify possible influences on electrochemical performance. Preparation of the battery cells prior to WVTR measurements includes opening of battery cells and extraction of electrode material, followed by resealing the encapsulations and adhesively mounting of gas couplings. A model describing the water diffusion through the thermal welds of the encapsulation are set up based on material analysis of the encapsulation material. Two WVTR equipments with different type of detectors are evaluated in this study. The results from the WVTR measurements show how important it is to perform this type of studies in dry environment and apply a rigorous precondition sequence before testing. Results from modelling confirm that the WVTR method has potential to be used for measurements of water diffusion into lithium-ion pouch cells. Consequently, WVTR measurements should be possible to use as a complement or alternative method to for example Karl Fisher titration.

  • 18.
    Svens, Pontus
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Lindström, Johan
    Scania CV AB, Södertälje, Sweden.
    Behm, Mårten
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Lindbergh, Göran
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    HEV lithium-ion battery testing and driving cycle analysis in a heavy-duty truck field study2012Inngår i: ECS Transactions: Volume 41, Issue 32, 2012, 2012, s. 12-26Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents early results from an ongoing field test of HEV batteries on heavy-duty trucks. The presented results focus on the parameters that can affect ageing, such as SOC and power. The goal with this study is to correlate battery ageing to battery usage. Commercial LMO/LTO lithium-ion battery cells were tested onboard four Scania trucks. The test equipment was designed for this type of HEV battery testing on conventional vehicles by emulating an HEV environment. This concept allows unobtrusive and low cost testing of battery cells under realistic conditions. Each truck is equipped with test equipment containing one cycled battery cell and one calendar aged cell. The hybrid strategy used in this test allows battery power and SOC to vary depending on drive pattern within certain limits. Battery capacity and resistance is measured periodically and this makes it possible to receive information about battery ageing without bringing the cells to the lab.

  • 19.
    Svens, Pontus
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Lindström, Johan
    Scania CV AB, Södertälje, Sweden.
    Gelin, Olle
    Scania CV AB, Södertälje, Sweden.
    Behm, Mårten
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Lindbergh, Göran
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Novel Field Test Equipment for Lithium-Ion Batteries in Hybrid Electrical Vehicle Applications2011Inngår i: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 4, nr 5, s. 741-757Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Lifetime testing of batteries for hybrid-electrical vehicles (HEV) is usually performed in the lab, either at the cell, module or battery pack level. Complementary field tests of battery packs in vehicles are also often performed. There are, however, difficulties related to field testing of battery-packs. Some examples are cost issues and the complexity of continuously collecting battery performance data, such as capacity fade and impedance increase. In this paper, a novel field test equipment designed primarily for lithium-ion battery cell testing is presented. This equipment is intended to be used on conventional vehicles, not hybrid vehicles, as a cheaper and faster field testing method for batteries, compared to full scale HEV testing. The equipment emulates an HEV environment for the tested battery cell by using real time vehicle sensor information and the existing starter battery as load and source. In addition to the emulated battery cycling, periodical capacity and pulse testing capability are implemented as well. This paper begins with presenting some background information about hybrid electrical vehicles and describing the limitations with today's HEV battery testing. Furthermore, the functionality of the test equipment is described in detail and, finally, results from verification of the equipment are presented and discussed.

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