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- Arvidsson, Rickard, 1984, et al.
(författare)
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Energy use and climate change improvements of Li/S batteries based on life cycle assessment
- 2018
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Ingår i: Journal of Power Sources. - : Elsevier BV. - 0378-7753. ; 383, s. 87-92
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Tidskriftsartikel (refereegranskat)abstract
- We present a life cycle assessment (LCA) study of a lithium/sulfur (Li/S) cell regarding its energy use (in electricity equivalents, kWhel) and climate change (in kg carbon dioxide equivalents, CO2 eq) with the aim of identifying improvement potentials. Possible improvements are illustrated by departing from a base case of Li/S battery design, electricity from coal power, and heat from natural gas. In the base case, energy use is calculated at 580 kWhel kWh−1 and climate change impact at 230 kg CO2 eq kWh−1 of storage capacity. The main contribution to energy use comes from the LiTFSI electrolyte salt production and the main contribution to climate change is electricity use during the cell production stage. By (i) reducing cell production electricity requirement, (ii) sourcing electricity and heat from renewable sources, (iii) improving the specific energy of the Li/S cell, and (iv) switching to carbon black for the cathode, energy use and climate change impact can be reduced by 54 and 93%, respectively. For climate change, our best-case result of 17 kg CO2 eq kWh−1 is of similar magnitude as the best-case literature results for lithium-ion batteries (LIBs). The lithium metal requirement of Li/S batteries and LIBs are also of similar magnitude.
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| 3. |
- Arvidsson, Rickard, 1984, et al.
(författare)
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Potential improvements of the life cycle environmental impacts of a Li/S battery cell
- 2018
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The lithium sulfur (Li/S) battery is a promising battery chemistry for two reasons: it requires no scarce metals apart from the lithium itself and it brings the promise of high specific energy density at the cell level. However, the environmental impacts of this battery type remain largely unstudied. In this study, we conducted a life cycle assessment (LCA) of the production of an Li/S cell to calculate these impacts. The anode consists of a lithium foil and the cathode consists of a carbon/sulfur composite. The electrolyte is a mixture of dioxalane, dimethoxyethane, lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and lithium nitrate. The current collector for the cathode is an aluminium foil and a tri-layer membrane of polypropylene and polyethylene acts as separator. The functional unit of the study is 1 kWh specific energy storage. Three key environmental impacts were considered: energy use, climate change and lithium requirement. In our baseline scenario, we consider the pilot-scale production of a battery with a specific energy of 300 kWh/kg, having the mesoporous material CMK-3 as carbon material in the carbon/sulfur cathode, and using coal power and natural gas heat as energy sources. This scenario results in an energy use of 580 kWh/kWhstored and a climate change impact of 230 kg CO2eq/kWhstored. The main contributor to energy use is the LiTFSI production and the main contributor to climate change is electricity use during cell production. We then model a number of possible improvements sequentially: (1) reduction of cell production electricity requirement due to production at industrial-scale, (2) sourcing of electricity and heat from renewable instead of fossil sources (i.e. solar power and biogas heat), (3) improvement of the specific energy of the Li/S cell to 500 kWh/kg and (4) a shift of the carbon material in the cathode to carbon black (without considering changes in performance). By implementing all these four improvements, energy use and climate change impact can be reduced by an impressive 54 and 93%, respectively. In particular, the improvements related to industrial-scale production and sourcing of renewable energy are considerable, whereas the shift of carbon material is of minor importance. For climate change, the best-case result of 17 kg CO2eq/kWhstored is similar to the best-case results reported in the scientific literature for lithium-ion batteries (LIBs). Regarding lithium requirement, the lithium metal requirement of Li/S batteries and LIBs are also of similar magnitude (0.33-0.55 kg/kWhstored and 0.2 kg/kWhstored, respectively). Using different allocation approaches did not alter the main conclusions of the study.
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- Johansson, Mathias, 1968
(författare)
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Application and Design Developments in Diffractive Optics
- 2001
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- There has been strong development in the field of diffractive optics (DO) in research laboratories over the past two decades. Much progress has been made, both in design and analysis, as well as in manufacturing techniques. However, so far DO have only reached the market in small numbers. This thesis reports on new applications and design methods, which may hopefully contribute to the spread of DO in society. A multichannel diffractive optic rotary joint was designed, manufactured and evaluated regarding cross talk, uniformity and wavelength sensitivity. An experimental cross-talk margin of 25 dB was reached. A new ultra-fast analog-to-digital conversion scheme, based on diffractive optics, was proposed. The optical part of the converter was tested experimentally with satisfactory results. To give a DO device anti-reflection properties, a subwavelength relief grating was superimposed on it. The manufactured device displayed significantly reduced reflectivity. High-fidelity replication of such a DO will result in low-cost, high performance components. An existing 1 x 8 reconfigurable free-space optical switch, based on a ferro-electric liquid-crystal-on-silicon spatial light modulator, was modified to operate adaptively under PC control. Using feedback, optical connections were established and maintained, the system automatically adapting to changes in the environment. An iterative algorithm for design of speckle-free diffraction patterns was developed. Experiment confirmed the speckle-free behavior. The algorithm uses repeated Fourier transformations and gentle modifications of the field amplitudes. An existing design algorithm for fan-outs was modified so that the uniformity of the diffraction spot patterns becomes less susceptible to a manufacturing relief-depth error. The uniformity is valuable for instance in laser machining, multiple line laser lithography and biomedical fluorescent sensing applications.
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| 8. |
- Risacher, C., et al.
(författare)
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A 279-381 GHz SIS Receiver for the APEX Telescope
- 2006
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Ingår i: Proceedings of the 16th International Symposium on Space Terahertz Technology, Chalmers University of Technology, Gothenburg, Sweden, May 2-4, 2005. ; , s. 432-437
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 9. |
- Sörstedt, Erik, 1980-, et al.
(författare)
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Computed tomographic colonography : Comparison of two workstations
- 2005
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Ingår i: Acta Radiologica. - : SAGE Publications. - 0284-1851 .- 1600-0455. ; 46:7, s. 671-678
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To compare two commercially available computed tomography (CT) colonography systems with respect to interobserver variability, the influence of level of expertise, and the gradual reduction of reviewing time for each system. Material and Methods: Two residents and two radiologists using Siemens CTAPP Colography software and Viatronix V3DColon software reviewed supine and prone CT acquisitions from 24 patients in a primary 3D endoluminal view. The observers graded each case with respect to technical quality and diagnostic value, assessed the presence of pathology, and indicated the time spent on the viewing. Results: Significant differences were found in technical quality ( P <0.001) and diagnostic value ( P <0.001) depending on which system was used, with higher scores for the Viatronix software. The agreement between specialists tended to be higher than that between residents (κ = 0.63 (0.30-0.95) vs. κ = 0.51 (0.21-0.81)), and the residents gave significantly ( P <0.001) higher scores of technical quality. However, the level of expertise had no significant impact on the assessments. We noted extensive variability in pathological lesions found by the different observers. The number of findings did not differ between workstations, but the viewers tended to report larger polyp sizes with the Viatronix software. The time needed for viewing decreased significantly from the first to the last examination viewed by each observer. Conclusion: Both the evaluated systems present trustworthy images of the human colon, but in a primary 3D setting the Viatronix software is favored owing to the userfriendly interface, higher experienced technical quality, and better diagnostic value. © 2005 Taylor & Francis.
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