A Study on Making the Lithium-ion Battery Electrodes: Mixing and Coating
| Autor: | Darjen Liu, 劉達人 |
|---|---|
| Rok vydání: | 2016 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 104 Lithium ion secondary batteries as energy storage devices have become popular in recent years. Electrodes manufacturing process which involves mixing the slurry, coating and drying directly affect the quality of the battery performance. The thesis is divided into two parts respectively discuss ways to improve this second program compared to traditional methods. Slurries for anodes and cathodes of lithium batteries contain a large percentage of solid particles of different chemicals, sizes and shapes in highly viscous media. A thorough mixing of these slurries poses a major challenge in the battery manufacturing process. Several types of mixing devices and mixing methods were examined. The conventional turbine stirrers or ball mill mixers could be adequately used for the preparation of anode slurries, but not suitable for cathode slurries. In this study, a newly three-dimensional mixer, in conjunction with a multi-stage mixing sequence were proposed. The mixing effectiveness was examined by means of rheological measurements and flow visualization techniques. Electrical performance results indicated that the battery obtained using the 3-D mixing device with a multi-stage mixing sequence was more efficient to those obtained from conventional methods. The cathode and anode electrodes in lithium-ion batteries typically contain a significant proportion of particles and binders. During the electrode drying process, the high temperature will lead to the so-called "binder migration" phenomenon. Uneven particle/binder distribution can cause poor adhesion between the coated layer and which will level to the substrate, disruption of conductive paths and decrease the electrode performance. In this study, a two-layered cathode was designed using separate compositions of slurry ingredients in each layer, as produced by means of a simultaneous multilayer coating method. The two-layered cathode with the top layer containing less binder than the bottom layer was found to yield a better particle/binder distribution in the final structure under high temperature drying. The battery made with the two-layered cathode appeared to give a better overall performance. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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