Techno-Economic Development Methodology for Mini-Environments in Battery Cell Production

Abstract

Due to the rising interest in electric vehicles, the demand for more efficient battery cells is increasing rapidly. To support this transformation, battery cells must become cheaper and environmentally friendly. Energy consumption during production is a major driver of costs and CO2 emissions. To fulfill societal demand, higher gravimetric and volumetric energy density of lithium-ion battery cells are required. Since these materials are significantly more sensitive to moisture, the production conditions need to be adapted accordingly. Therefore, the preparation of clean and extremely dry atmospheric conditions is crucial for production of high-quality battery cells. The technology approach "Mini-Environment" enables the substitution of conventional clean- and dry-rooms for significant energy and cost savings. However, the diverse product- and process-specific characteristics along the value chain require individual solutions to enable Mini-Environments for highly automated battery cell production. Due to multiple interacting requirements and characteristics, such as operator interventions, logistics interfaces and air handling procedures, there is a very high diversity of variants for the machine equipment design. Moreover, typical methodological procedures for development of quality-oriented and energy efficient production machines remain less applicable to the early stages of technological development. Both issues lead to the research questions, how to identify the independencies between costs, air handling, product and process characteristics and how to reach the most techno-economical machine design. To answer these questions, a systematic techno-economic development procedure was conducted. Following a four-phase analytical approach, based on an extended morphological box, cost analysis, techno-economic utility analysis and sensitivity loop, different Mini-Environment concepts were constructed, analyzed and cross-evaluated. The study also forecasts the CO2 emission rate reduction and cost savings compared to alternative machine concepts. In summary, a fully interlinked system design was adapted on a cell assembly line with a cost-saving potential of 56% for future battery cell production.