A cost model for the manufacture ofbipolar plates using micro milling

[摘要] ENGLISH ABSTRACT: In a move towards cleaner and more sustainable energy systems, hydrogen as an energy carrier andhydrogen fuel cells as energy converters are receiving increasing global attention. Considering thevital role that platinum plays in the operation of hydrogen fuels cells, South Africa stands to gainenormously as the world's leading platinum group metals supplier. Therefore, in order to benefitacross the whole value chain, it is imperative to develop the capability to manufacture hydrogen fuelcell stacks locally.This project addresses this imperative, in part, by building a framework to evaluate themanufacturing performance of one of the more costly components of the hydrogen fuel cell stack.More specifically, this project builds a cost evaluation model (or cost model) for the manufacture ofbipolar plates using micro milling. In essence, the model characterises manufacturing cost (and time)as a function of relevant inputs.The model endeavours to be flexible in accommodating relevant contributing cost drivers such astool life and manufacturing time. Moreover, the model lays the groundwork, from a micro millingperspective, for a comparison of different manufacturing methods for bipolar plates.The approach taken in building the cost model is a fundamental one, owing to the lack of historicalcost data for this particular process. As such, manufacturing knowledge and experimentation areused to build the cost model in a structured way.The process followed in building the cost model begins with the formulation of the cost componentsby reviewing relevant examples from literature. Thereafter, two main cost drivers arecomprehensively addressed. Tool life is characterised experimentally as a function of cuttingparameters and manufacturing time is characterised as a function of relevant inputs. The work isthen synthesized into a coherent cost model.Following the completion of the cost model, analysis is done to find the near-optimal combination ofmachine cutting parameters. Further, analysis is done to quantify the sensitivity of manufacturingcost to design changes and production volumes. This attempts to demonstrate how typicalmanagerial issues can be addressed using the cost model format.The value of this work must be seen in terms of its practical contribution. That is, its contribution tothe development of the capability to manufacture hydrogen fuel cells locally. By understanding theeffect of relevant input factors on manufacturing cost, 'upstream' design and development activitiescan be integrated with 'downstream' manufacturing activities. Therefore, this project supports thedevelopment of manufacturing capability by providing a mechanism to control cost throughout theprocess.

[发布机构] Stellenbosch University