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Xu, J. & Varna, J. (2019). Matrix and interface microcracking in carbon fiber/polymer structural micro-battery. Journal of composite materials
Open this publication in new window or tab >>Matrix and interface microcracking in carbon fiber/polymer structural micro-battery
2019 (English)In: Journal of composite materials, ISSN 0021-9983, E-ISSN 1530-793XArticle in journal (Refereed) Epub ahead of print
Abstract [en]

In this paper, the propagation of radial matrix cracks and debond cracks at the coating/matrix interface in unidirectional carbon fiber structural micro-battery composite are studied numerically. The micro battery consists of a solid electrolyte-coated carbon fiber embedded in an electrochemically active polymer matrix. Stress analysis shows that high hoop stress in the matrix during charging may initiate radial matrix cracks at the coating/matrix interface. Several 2-D finite element models of the transverse plane with different arrangements of fibers and other matrix cracks were used to analyze the radial matrix crack growth from the coating/matrix interface of the central fiber in a composite with a square packing of fibers. Energy release rates of radial cracks along two potential propagation paths are calculated under pure electrochemical loading. The presence of a radial matrix crack imposes changes in the stress distribution along the coating/matrix interface, making debonding relevant for consideration. Results for energy release rates show that the debond crack growth is governed by mode II.

Place, publisher, year, edition, pages
Sage Publications, 2019
Keywords
Carbon fiber composite, intercalation, micro-battery, microcracking, modeling
National Category
Composite Science and Engineering
Research subject
Polymeric Composite Materials
Identifiers
urn:nbn:se:ltu:diva-74910 (URN)10.1177/0021998319843616 (DOI)2-s2.0-85064940549 (Scopus ID)
Available from: 2019-06-24 Created: 2019-06-24 Last updated: 2019-06-24
Xu, J. (2019). Structural Composite Lithium-Ion Battery: Effect of Intercalation induced volumetric changes on micro-damage. (Doctoral dissertation). Luleå: Luleå University of Technology
Open this publication in new window or tab >>Structural Composite Lithium-Ion Battery: Effect of Intercalation induced volumetric changes on micro-damage
2019 (English)Doctoral thesis, comprehensive summary (Other academic)
Alternative title[sv]
Strukturella Litium-jon kompositbatterier : Mikroskador orsakade av volymändringar isamband med interkalering
Abstract [en]

The quest for lighter materials and structures to reduce climate impacts in the automotive industry has paved the way for multifunctional solutions. Mass saving on a system level can be achieved by materials or structures having more than one primary function, thus reducing the number of components used. Structural batteries are composite materials that simultaneously carry mechanical loads while delivering electrical energy. While carbon fiber is a commonly used reinforcing material in high-performance composite materials, it also possesses excellent lithium intercalation properties.Therefore,it is possible to use carbon fiber to develop structural batteries based onlithium-ion battery technology.

Among several proposed solutions,the micro-battery employs the carbon fiber asa negative electrodeof the battery and also as a composite reinforcement material. The fiber is coated with a solid polymer electrolyte which works as an ion conductor and separator whilst transferring mechanical loads. The coated fiber is surrounded by additional matrix material acting asapositive electrode, composed of conductive additives, active electrode material and electrolyte. This assembly of materials allows thenecessary electrochemical processes to occur simultaneously, including electrochemical reactions at the surface of the active electrode material, mass transport within active electrode material by diffusion, mass transport in electrolyte by diffusion and migration, and electronic conduction.

During electrochemical cycling the electrodes undergo volume changes as a result of lithium transport. The work in this thesis addresses the effects of volume changes on internal mechanical stress state in the structural battery. A physics-based mathematical model employing a number of coupled nonlinear differential equations has been set-up and solved numerically to investigate performance in the structural battery material. The resulting transient lithium ionconcentration distributions were used in combination with linear elastic analysis in order to assess the mechanical stresses in the fiber, coating and matrix caused by non-uniform swelling and shrinking of the micro-battery. Stress analysis shows that high hoop stress in the matrix during charging may initiate radial matrix cracks at the coating/matrix interface. Linear elastic fracture mechanics hasbeen used to analyze radial matrix crack propagation and debonding at coating/matrix interface in both unidirectional (UD) and cross-ply laminate, under electrochemical load only and combined electrochemical and thermomechanical load. Results show that for cross-ply structural battery composite the sequence of macro-scale crack forming events differs from a conventional cross-plied composite, as well as froma UD composite battery laminate. The most likely course of failure events in a cross-ply laminate were found to be: 1) radial matrix crack initiation and unstable growth; 2)matrix/coatingdebond when the matrix crack hasacertain length.

Place, publisher, year, edition, pages
Luleå: Luleå University of Technology, 2019
Series
Doctoral thesis / Luleå University of Technology 1 jan 1997 → …, ISSN 1402-1544
National Category
Composite Science and Engineering
Research subject
Polymeric Composite Materials
Identifiers
urn:nbn:se:ltu:diva-72810 (URN)978-91-7790-312-3 (ISBN)978-91-7790-313-0 (ISBN)
Public defence
2019-03-29, E231, Luleå, 08:30 (English)
Opponent
Supervisors
Available from: 2019-02-07 Created: 2019-02-07 Last updated: 2019-03-19Bibliographically approved
Xu, J., Lindbergh, G. & Varna, J. (2018). Carbon fiber composites with battery function: Stresses and dimensional changes due to Li-ion diffusion. Journal of composite materials, 52(20), 2729-2742
Open this publication in new window or tab >>Carbon fiber composites with battery function: Stresses and dimensional changes due to Li-ion diffusion
2018 (English)In: Journal of composite materials, ISSN 0021-9983, E-ISSN 1530-793X, Vol. 52, no 20, p. 2729-2742Article in journal (Refereed) Published
Abstract [en]

Structural composite materials that simultaneously carry mechanical loads, while storing electrical energy offers the potential of significantly reduced total component weight owing to the multifunctionality. In the suggested micro-battery, the carbon fiber is employed as a negative electrode of the battery and also as a composite reinforcement material. It is coated with a solid polymer electrolyte working as an ion conductor and separator while transferring mechanical loads. The coated fiber is surrounded by a conductive positive electrode material matrix. This paper demonstrates a computational methodology for addressing mechanical stresses arising in a conceptualized micro-battery and dimensional changes of the cell during electrochemical cycling, caused by time-dependent gradients in lithium ion concentration distribution.

Place, publisher, year, edition, pages
Sage Publications, 2018
National Category
Composite Science and Engineering
Research subject
Polymeric Composite Materials
Identifiers
urn:nbn:se:ltu:diva-67699 (URN)10.1177/0021998317752825 (DOI)000441034800003 ()2-s2.0-85051282917 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-08-08 (rokbeg)

Available from: 2018-02-20 Created: 2018-02-20 Last updated: 2018-08-23Bibliographically approved
Hagberg, J., Maples, H. A., Alvim, K. S. .., Xu, J., Johannisson, W., Bismarck, A., . . . Lindbergh, G. (2018). Lithium iron phosphate coated carbon fiber electrodes for structural lithium ion batteries. Composites Science And Technology, 162, 235-243
Open this publication in new window or tab >>Lithium iron phosphate coated carbon fiber electrodes for structural lithium ion batteries
Show others...
2018 (English)In: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 162, p. 235-243Article in journal (Refereed) Published
Abstract [en]

A structural lithium ion battery is a material that can carry load and simultaneously be used to store electrical energy. We describe a path to manufacture structural positive electrodes via electrophoretic deposition (EPD) of LiFePO4 (LFP), carbon black and polyvinylidene fluoride (PVDF) onto carbon fibers. The carbon fibers act as load-bearers as well as current collectors. The quality of the coating was studied using scanning electron microscopy and energy dispersive X-ray spectroscopy. The active electrode material (LFP particles), conductive additive (carbon black) and binder (PVDF) were found to be well dispersed on the surface of the carbon fibers. Electrochemical characterization revealed a specific capacity of around 60–110 mAh g−1 with good rate performance and high coulombic efficiency. The cell was stable during cycling, with a capacity retention of around 0.5 after 1000 cycles, which indicates that the coating remained well adhered to the fibers. To investigate the adhesion of the coating, the carbon fibers were made into composite laminae in epoxy resin, and then tested using 3-point bending and double cantilever beam (DCB) tests. The former showed a small difference between coated and uncoated carbon fibers, suggesting good adhesion. The latter showed a critical strain energy release rate of ∼200–600 J m−2 for coated carbon fibers and ∼500 J m−2 for uncoated fibers, which also indicates good adhesion. This study shows that EPD can be used to produce viable structural positive electrodes.

Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Composite Science and Engineering
Research subject
Polymeric Composite Materials
Identifiers
urn:nbn:se:ltu:diva-68651 (URN)10.1016/j.compscitech.2018.04.041 (DOI)000438180500028 ()2-s2.0-85046657191 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-06-27 (andbra)

Available from: 2018-05-07 Created: 2018-05-07 Last updated: 2019-04-02Bibliographically approved
Xu, J. (2017). Structural Lithium-ion battery: Multiphysics modeling of mechanical and electrochemical phenomena. (Licentiate dissertation). Luleå: Luleå University of Technology
Open this publication in new window or tab >>Structural Lithium-ion battery: Multiphysics modeling of mechanical and electrochemical phenomena
2017 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

The quest for lighter materials and structures to reduce climate impacts in the automotive industry has paved the way for multifunctional solutions. Mass saving on a system level can be achieved by materials or structures having more than one primary function, thus reducing the number of components used. Structural batteries are composite materials that simultaneously carry mechanical loads while delivering electrical energy. While carbon fiber is a commonly used reinforcing material in high-performance composite materials, it also possesses excellent lithium intercalation properties. Therefore it is possible to use carbon fiber to develop structural batteries based on the lithium-ion battery technology. 

In the micro-battery, which is one of several design solutions, the carbon fiber is employed as a negative electrode of the battery and also as a composite reinforcement material. It is coated with a solid polymer electrolyte working as an ion conductor and separator whilst transferring mechanical loads. The coated fiber is surrounded by additional matrix material acting as cathode and transferring loads to the fibers, composed of conductive additives, active electrode material and electrolyte. This assembly of materials allows for the necessary electrochemical processes to occur simultaneously, including electrochemical reactions at the surface of the active electrode material, mass transport within active electrode material by diffusion, mass transport in electrolyte by diffusion and migration, and electronic conduction. 

During electrochemical cycling the electrodes undergo volume changes as a result of lithium transport. The work in this thesis addresses modeling of the effects of volume changes on internal mechanical stress state in the structural battery, potentially causing micro-damage formation in the material, which degrade both electrical and mechanical performance of the structural battery composite. 

In this work, a physics-based mathematical model employing a number of coupled nonlinear differential equations has been set-up and solved numerically to investigate performance in the structural battery material. The resulting transient Li concentration distributions were used in combination with linear elastic stress analysis in order to assess the mechanical stresses in the fiber, coating and matrix caused by non-uniform swelling and shrinking of the micro-battery. 

Place, publisher, year, edition, pages
Luleå: Luleå University of Technology, 2017
Series
Licentiate thesis / Luleå University of Technology, ISSN 1402-1757
National Category
Composite Science and Engineering
Research subject
Polymeric Composite Materials
Identifiers
urn:nbn:se:ltu:diva-63048 (URN)978-91-7583-882-3 (ISBN)978-91-7583-883-0 (ISBN)
Presentation
2017-05-23, E231, Luleå, 15:00
Available from: 2017-04-19 Created: 2017-04-18 Last updated: 2018-02-21Bibliographically approved
Xu, J., Pupurs, A., Lindbergh, G. & Varna, J. (2016). Multifunctional composites: Modeling intercalation induced stresses in constituents of micro-battery. In: ECCM 2016: Proceeding of the 17th European Conference on Composite Materials. Paper presented at 17th European Conference on Composite Materials, Munich, Germany, 26-30th June 2016. European Conference on Composite Materials
Open this publication in new window or tab >>Multifunctional composites: Modeling intercalation induced stresses in constituents of micro-battery
2016 (English)In: ECCM 2016: Proceeding of the 17th European Conference on Composite Materials, European Conference on Composite Materials , 2016Conference paper, Published paper (Refereed)
Abstract [en]

A structural battery that simultaneously carries mechanical loads while storing electrical energy offers the potential of significantly reduced total vehicle weight owing to the multifunctionality. Carbon fiber is employed as negative electrode of the battery and also as a composite reinforcement material. It is coated with a solid polymer electrolyte working as an ion conductor and separator whilst transferring mechanical loads. The coated fiber is surrounded by a conductive positive electrode material. This paper demonstrates a methodology for addressing mechanical stresses arising in a conceptualized micro battery cell during electrochemical cycling, caused by time dependent gradients in lithium ion concentration distribution in the carbon fiber

Place, publisher, year, edition, pages
European Conference on Composite Materials, 2016
National Category
Composite Science and Engineering
Research subject
Polymeric Composite Materials
Identifiers
urn:nbn:se:ltu:diva-63253 (URN)2-s2.0-85017678172 (Scopus ID)978-3-00-053387-7 (ISBN)
Conference
17th European Conference on Composite Materials, Munich, Germany, 26-30th June 2016
Available from: 2017-05-05 Created: 2017-05-05 Last updated: 2018-02-21Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-3186-9561

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