Thermal Conductivity and Compaction of GDL-MPL Interfacial Composite Material

Bock, Robert; Shum, Andrew D.; Xiao, Xianghui; Karoliussen, Håvard; Seland, Frode; Zenyuk, Iryna V.; Burheim, Odne Stokke

doi:10.1149/2.0751807jes

Cited by 32 publications

(22 citation statements)

References 41 publications

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“…The thermal conductivity measurements for this study were performed ex situ in a custom-built measurement rig, which is sketched in Figure 1, similar to the one in Reference [53]. The rig applies a constant heat flux through a cylindrical geometry.…”

Section: Thermal Conductivity Measurementsmentioning

confidence: 99%

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Thermal Gradients with Sintered Solid State Electrolytes in Lithium-Ion Batteries

Bock

Onsrud²,

Karoliussen

et al. 2020

Energies

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The electrolyte is one of the three essential constituents of a Lithium-Ion battery (LiB) in addition to the anode and cathode. During increasingly high power and high current charging and discharging, the requirement for the electrolyte becomes more strict. Solid State Electrolyte (SSE) sees its niche for high power applications due to its ability to suppress concentration polarization and otherwise stable properties also related to safety. During high power and high current cycling, heat management becomes more important and thermal conductivity measurements are needed. In this work, thermal conductivity was measured for three types of solid state electrolytes: Li 7 La 3 Zr 2 O 12 (LLZO), Li 1.5 Al 0.5 Ge 1.5 (PO 4 ) 3 (LAGP), and Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 (LATP) at different compaction pressures. LAGP and LATP were measured after sintering, and LLZO was measured before and after sintering the sample material. Thermal conductivity for the sintered electrolytes was measured to 0.470 ± 0.009 WK − 1 m − 1 , 0.5 ± 0.2 WK − 1 m − 1 and 0.49 ± 0.02 WK − 1 m − 1 for LLZO, LAGP, and LATP respectively. Before sintering, LLZO showed a thermal conductivity of 0.22 ± 0.02 WK − 1 m − 1 . An analytical temperature distribution model for a battery stack of 24 cells shows temperature differences between battery center and edge of 1–2 K for standard liquid electrolytes and 7–9 K for solid state electrolytes, both at the same C-rate of four.

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Section: Thermal Conductivity Measurementsmentioning

confidence: 99%

“…The given error in the results shows the deviation from the expected linear trend of thermal resistance against sample thickness. Further details on the measurement rig and the procedure can be found in Reference [53].…”

Section: Thermal Conductivity Measurementsmentioning

confidence: 99%

Thermal Gradients with Sintered Solid State Electrolytes in Lithium-Ion Batteries

Bock

Onsrud²,

Karoliussen

et al. 2020

Energies

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“…They investigated the influence of changes in temperature, PTFE content, compaction pressure, and water content. Their findings are summarized in [19], however, non of these cover the thermal conductivity of the catalytic layer itself.…”

Section: Thermal Conductivitymentioning

confidence: 99%

“…Research interest on this topic started to surface around 20 years ago and has been gaining momentum ever since. Several research groups have published thermal models with varying degrees of detail [21][22][23][24][25][26][27][28][29], see [19] for a more detailed summary. In a recent book chapter, Secanell et al (2017) review the current modeling approaches in PEMFCs, also discussing heat transport in detail [2].…”

Section: Thermal Modelsmentioning

confidence: 99%

The influence of graphitization on the thermal conductivity of catalyst layers and temperature gradients in proton exchange membrane fuel cells

Bock

Karoliussen

Pollet

et al. 2020

International Journal of Hydrogen Energy

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As the proton exchange membrane fuel cell (PEMFC) has improved its performance and power density, the efficiency has remained unchanged. With around half the reaction enthalpy released as heat, thermal gradients grow. To improve the understanding of such gradients, PEMFC component thermal conductivity has been increasingly investigated over the last ten years, and the catalyst layer (CL) is one of the components where thermal conductivity values are still scarce. CLs in PEMFC are where the electrochemical reactions occur and most of the heat is released. The thermal conductivity in this region affects the heat distribution significantly within a PEMFC. Thermal conductivities for a graphitized and a non-graphitized CL were measured for compaction pressures in the range of 3 and 23 bar. The graphitized CL has a thermal conductivity of 0.12 ± 0.05 WK −1 m −1 , whilst the non-graphitized CL conductivity is 0.061 ± 0.006 WK −1 m −1 , both at 10 bar compaction pressure. These results suggest that the graphitization of the catalyst material causes a doubling of the thermal conductivity of the CL. This important finding bridges the very few existing studies. Additionally, a 2D thermal model was constructed to represent the impact of the results on the temperature distribution inside a fuel cell.

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“…We attribute this to an expected difference in thermal conductivity for the two cathode GDM used in these PEMFCs. Fibrous GDL substrates from Freudenberg have been shown to have a lower thermal conductivity than those GDL substrates developed by SGL [37,38]. With a lower thermal conductivity in the cathode GDL substrate, the cathode catalyst layer temperature would increase, facilitating product water evaporation for rejection from the cathode.…”

Section: Pemfc Performance In Dead-ended Anode (Dea) Modementioning

confidence: 99%

Effect of GDM Pairing on PEMFC Performance in Flow-Through and Dead-Ended Anode Mode

et al. 2020

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Asymmetric gas diffusion media (GDM) pairing, which feature distinct GDM at the anode and cathode of the proton electrolyte membrane fuel cell (PEMFC), enhance water management compared to symmetric pairing of GDM (anode and cathode GDM are identical). An asymmetric pairing of Freudenberg GDM (H24C3 at anode and H23C2 at cathode) reduces ohmic resistances by up to 40% and oxygen transport resistances by 14% en route to 25% higher current density in dry gas flows. The asymmetric GDM pairing effectively hydrates the membrane electrode assembly (MEA) while minimizing liquid water saturation in the cathode compared to a commonly used symmetric GDM pairing of SGL 29BC at the anode and cathode. Superior water management observed with asymmetric GDM in flow-through mode is also realized in dead-ended anode (DEA) mode. Compared to the symmetric GDM pairing, the asymmetric GDM pairing with Freudenberg GDM increases cell voltage at all current densities, extends and stabilizes steady-state voltage behavior, slows voltage decay, and vastly reduces the frequency of anode purge events. These results support that the asymmetric Freudenberg GDM combination renders the PEMFC less prone to anode water saturation and performance loss from the anticipated increase in water back-diffusion during DEA mode operation.

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Thermal Conductivity and Compaction of GDL-MPL Interfacial Composite Material

Cited by 32 publications

References 41 publications

Thermal Gradients with Sintered Solid State Electrolytes in Lithium-Ion Batteries

Thermal Gradients with Sintered Solid State Electrolytes in Lithium-Ion Batteries

The influence of graphitization on the thermal conductivity of catalyst layers and temperature gradients in proton exchange membrane fuel cells

Effect of GDM Pairing on PEMFC Performance in Flow-Through and Dead-Ended Anode Mode

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