Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Performance of Conventional and Structural Lithium-Ion Batteries
KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
2013 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Lithium-ion batteries have, in recent years, experienced a rapid development from small everyday devices towards hybrid electric vehicle (HEV) applications. Due to this shift in application area, the battery performance andits degradation with time are becoming increasingly important issues to besolved.In this thesis, lithium-ion batteries are investigated with focus on lifetime performance of an existing battery chemistry, and development of electrodes for so-called structural batteries. The systems are evaluated by electrochemical methods, such as cycling and electrochemical impedance spectroscopy (EIS),combined with material characterization and modeling.

Lifetime performance of mesocarbon microbeads (MCMB)/LiFePO4 cells was investigated to develop an understanding of how this technology tolerates and is influenced by different conditions, such as cycling, storage and temperature.The lifetime of the LiFePO4-based cells was found to be significantly reduced by cycling at elevated temperature, almost five times shorter compared to cycle-aged cells at ambient temperature. The calendar-aged cells also showed major signs of degradation at elevated temperatures. The overall cause of aging was electrolyte decomposition which resulted in loss of cyclable lithium, i.e. capacity fade, and impedance increase.

Commercially available polyacrylonitrile (PAN)-based carbon fibers were investigated, both electrochemically and mechanically, to determine their suitability as negative electrodes in structural batteries. The electrochemical performance of carbon fibers was found to be excellent compared to other negative electrode materials, especially for single or well-separated fibers. The mechanical properties, measured as changes in the tensile properties, showed that the tensile stiffness was unaffected by lithium-ion intercalation and cycling. The ultimate tensile strength, however, showed a distinct variation with state-of-charge (SOC). Overall, carbon fibers are suitable for structural battery applications.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2013. , 48 p.
Series
Trita-CHE-Report, ISSN 1654-1081 ; 2013:28
National Category
Chemical Engineering
Identifiers
URN: urn:nbn:se:kth:diva-122875ISBN: 978-91-7501-774-7 (print)OAI: oai:DiVA.org:kth-122875DiVA: diva2:623824
Public defence
2013-06-12, K2, Teknikringen 28, KTH, Stockholm, 10:00 (English)
Opponent
Supervisors
Note

QC 20130529

Available from: 2013-05-29 Created: 2013-05-28 Last updated: 2013-05-29Bibliographically approved
List of papers
1. Comparing aging of MCMB graphite/LiFePO4 cells at 22 °C and 55 °C – Electrochemical and photoelectron spectroscopy studies.
Open this publication in new window or tab >>Comparing aging of MCMB graphite/LiFePO4 cells at 22 °C and 55 °C – Electrochemical and photoelectron spectroscopy studies.
Show others...
(English)Manuscript (preprint) (Other academic)
Abstract [en]

Accelerated aging at elevated temperature is commonly used to test lithium-ion battery lifetime, but the effect of an elevated temperature is still not well understood. If aging at elevated temperature would only be faster, but in all other respects equivalent to aging at ambient temperature, cells aged to end-of-life (EOL) at different temperatures would be very similar. The present study compares graphite/LiFePO4-based cells either cycle- or calendar-aged to EOL at 22 °C and 55 °C. Cells cycled at the two temperatures show differences in electrochemical impedance spectra as well as in X-ray photoelectron spectroscopy (XPS) spectra. These results show that lithium-ion cell aging is a complex set of processes. At elevated temperature, the aging is accelerated in process specific ways. Furthermore, the XPS results of cycle-aged samples indicate increased deposition of oxygenated LiPF6 decomposition products in both the negative and positive electrode/electrolyte interfaces. The decomposition seems more pronounced at elevated temperature, and largely accelerated by cycling, which could contribute to the observed cell impedance increase.

National Category
Chemical Engineering
Identifiers
urn:nbn:se:kth:diva-122443 (URN)
Funder
StandUp
Note

QC 20160622

The manuscript has been revised and published under the title "Comparing aging of graphite/LiFePO4 cells at 22 degrees C and 55 degrees C - Electrochemical and photoelectron spectroscopy studies"

Available from: 2013-05-21 Created: 2013-05-21 Last updated: 2016-06-22Bibliographically approved
2. Aging in Lithium-Ion Batteries: Experimental and Model Investigation of Harvested LiFePO4 and Mesocarbon Microbead Graphite Electrodes
Open this publication in new window or tab >>Aging in Lithium-Ion Batteries: Experimental and Model Investigation of Harvested LiFePO4 and Mesocarbon Microbead Graphite Electrodes
Show others...
2013 (English)In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 110, 335-348 p.Article in journal (Refereed) Published
Abstract [en]

This study investigates aging in LiFePO4/mesocarbon microbead graphite cells that have been subjected to either a synthetic hybrid drive cycle or calendar aging, at 22 C. The investigation involves detailed examination and comparison of harvested fresh and aged electrodes. The electrode properties are determined using a physics-based electrochemical impedance spectroscopy (EIS) model that is fitted to three-electrode EIS measurements, with input from measured electrode capacity and scanning electrode microscopy (SEM). Results from the model fitting provide a detailed insight to the electrode degradation and is put into context with the behavior of the full cell aging. It was established that calendar aging has negligible effect on cell impedance, while cycle aging increases the impedance mainly due to structural changes in the LiFePO4 porous electrode and electrolyte decomposition products on both electrodes. Further, full-cell capacity fade is mainly a consequence of cyclable lithium loss caused by electrolyte decomposition.

Keyword
Lithium-ion battery, Aging, EIS modeling, LiFePO4, Graphite
National Category
Chemical Engineering
Identifiers
urn:nbn:se:kth:diva-122395 (URN)10.1016/j.electacta.2013.05.081 (DOI)000329530300044 ()2-s2.0-84888320795 (Scopus ID)
Funder
StandUpSwedish Energy Agency
Note

 QC 20140120. Updated from "Accepted" to "Published".

Available from: 2013-05-20 Created: 2013-05-20 Last updated: 2017-12-06Bibliographically approved
3. PAN-based carbon fiber negative electrodes for structural lithium-ion batteries
Open this publication in new window or tab >>PAN-based carbon fiber negative electrodes for structural lithium-ion batteries
Show others...
2011 (English)In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 158, no 12, A1455-A1460 p.Article in journal (Refereed) Published
Abstract [en]

Several grades of commercially-available polyacrylonitrile (PAN)-based carbon fibers have been studied for structural lithium-ion batteries to understand how the sizing, different lithiation rates and number of fibers per tow affect the available reversible capacity, when used as both current collector and electrode, for use in structural batteries. The study shows that at moderate lithiation rates, 100 mA g-1, most of the carbon fibers display a reversible capacity close to or above 100 mAh g-1 after ten full cycles. For most of the fibers, removing the sizing increased the capacity to some extent. However, the main factor affecting the measured capacity was the lithiation rate. Decreasing the current by a tenth yielded an increase of capacity of around 100 for all the tested grades. From the measurements performed in this study it is evident that carbon fibers can be used as the active negative material and current collector in structural batteries. © 2011 The Electrochemical Society.

Place, publisher, year, edition, pages
The Electrochemical Society Inc., 2011
National Category
Chemical Engineering
Identifiers
urn:nbn:se:kth:diva-80613 (URN)10.1149/2.053112jes (DOI)000297979300031 ()2-s2.0-81355132992 (Scopus ID)
Funder
TrenOp, Transport Research Environment with Novel PerspectivesStandUpSwedish Foundation for Strategic Research
Note

Source: Scopus. QC 20120210

Available from: 2012-02-10 Created: 2012-02-10 Last updated: 2017-12-07Bibliographically approved
4. Characterization of Lithium Intercalation Processes of PAN-based Carbon Fibers in a Microelectrode System
Open this publication in new window or tab >>Characterization of Lithium Intercalation Processes of PAN-based Carbon Fibers in a Microelectrode System
(English)Article in journal (Other academic) Submitted
National Category
Chemical Engineering
Identifiers
urn:nbn:se:kth:diva-122398 (URN)
Funder
StandUp
Note

QC 20160622

Available from: 2013-05-20 Created: 2013-05-20 Last updated: 2016-06-22Bibliographically approved
5. Impact of electrochemical cycling on the tensile properties of carbon fibres for structural lithium-ion composite batteries
Open this publication in new window or tab >>Impact of electrochemical cycling on the tensile properties of carbon fibres for structural lithium-ion composite batteries
Show others...
2012 (English)In: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 72, no 7, 792-798 p.Article in journal (Refereed) Published
Abstract [en]

Carbon fibres are particularly well suited for use in a multifunctional lightweight design of a structural composite material able to store energy as a lithium-ion battery. The fibres will in this case act as both a high performance structural reinforcement and one of the battery electrodes. However, the electrochemical cycling consists of insertions and extractions of lithium ions in the microstructure of carbon fibres and its impact on the mechanical performance is unknown. This study investigates the changes in the tensile properties of carbon fibres after they have been subjected to a number of electrochemical cycles. Consistent carbon fibre specimens were manufactured with polyacrylonitrile-based carbon fibres. Sized T800H and desized IMS65 were selected for their mechanical properties and electrochemical capacities. At the first lithiation the ultimate tensile strength of the fibres was reduced of about 20% but after the first delithiation some strength was recovered. The losses and recoveries of strength remained unchanged with the number of cycles as long as the cell capacity remained reversible. Losses in the cell capacity after 1000 cycles were measured together with smaller losses in the tensile strength of the lithiated fibres. These results show that electrochemical cycling does not degrade the tensile properties which seem to depend on the amount of lithium ions inserted and extracted. Both fibre grades exhibited the same trends of results. The tensile stiffness was not affected by the cycling. Field emission scanning electron microscope images taken after electrochemical cycling did not show any obvious damage of the outer surface of the fibres.

Place, publisher, year, edition, pages
Elsevier, 2012
Keyword
Carbon fibres, Hybrid composites, Strength, Mechanical properties, Electrochemical cycling
National Category
Other Engineering and Technologies
Identifiers
urn:nbn:se:kth:diva-95102 (URN)10.1016/j.compscitech.2012.02.006 (DOI)000302987800005 ()2-s2.0-84858793641 (Scopus ID)
Funder
Swedish Foundation for Strategic Research StandUpTrenOp, Transport Research Environment with Novel Perspectives
Note

QC 20120522

Available from: 2012-05-22 Created: 2012-05-14 Last updated: 2017-12-07Bibliographically approved
6. Expansion of carbon fibres induced by lithium intercalation for structural electrode applications
Open this publication in new window or tab >>Expansion of carbon fibres induced by lithium intercalation for structural electrode applications
Show others...
2013 (English)In: Carbon, ISSN 0008-6223, E-ISSN 1873-3891, Vol. 59, 246-254 p.Article in journal (Refereed) Published
Abstract [en]

Carbon fibres (CFs) can work as lightweight structural electrodes in CF-reinforced composites able to store energy as lithium (Li)-ion batteries. The CF has high stiffness and strength-to-weight ratios and a carbonaceous microstructure which enables Li intercalation. An innovative in situ technique for studying the longitudinal expansion of the CF and the relationship with the amount of intercalated Li is described in the present paper. The polyacrylonitrile-based CFs, T800H and unsized IMS65, were chosen for their electrochemical storage capacities. It was found that the CF expands during lithiation and contracts during delithiation. At the first electrochemical cycle, the expansion is partly irreversible which supports that the first-cycle capacity loss partly relates to Li trapped in the CF structure. For the following cycles, the capacity and the expansion are reversible. The expansion, which might relate to tensile stress, increases up to 1% as the measured capacity approaches the theoretical limit of 372 mAh/g for Li storage in graphite. Minor additional expansions due to the uneven distribution of intercalated Li in the CF structure were measured before and after lithiations. Using scanning electron microscope images the transverse expansion of fully lithiated CFs was estimated to about 10% of the cross-section area.

Place, publisher, year, edition, pages
Elsevier, 2013
Keyword
Ion Batteries, Graphite, Modulus
National Category
Other Engineering and Technologies
Identifiers
urn:nbn:se:kth:diva-122874 (URN)10.1016/j.carbon.2013.03.015 (DOI)000320489300025 ()2-s2.0-84877692135 (Scopus ID)
Funder
Swedish Foundation for Strategic Research , RMA08-0002Swedish Research Council, 621-2012-3764StandUp
Note

QC 20130529

Available from: 2013-05-28 Created: 2013-05-28 Last updated: 2017-12-06Bibliographically approved

Open Access in DiVA

fulltext(4096 kB)1738 downloads
File information
File name FULLTEXT01.pdfFile size 4096 kBChecksum SHA-512
4eb32bc97ad8afa7327faa7ddf3b3c8c36e4220125d9516ebff1a3a8d4b15079f48c392bd8fc5bfd4f80582a72c236a04b7593f032aa42e916185f9522845597
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Hellqvist Kjell, Maria
By organisation
Applied Electrochemistry
Chemical Engineering

Search outside of DiVA

GoogleGoogle Scholar
Total: 1738 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 1284 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf