Procedure for Influence Analysis of Large Cell Formats on the Battery Safety

摘要

Lithium-ion cells are used as energy storage in a wide range of applications. The battery components such as electrodes, separators and electrolyte are surrounded by a housing which is subject to various requirements. For example, the cell interior must be protected from external influences as moisture and dirt, whereas at the same time, the release of internal cell substances, several of them are toxic and flammable, must be prevented. In addition, the cell housing must provide the cooling function, fulfil requirements with regard to module integration and be as cost-effective as possible and easy to manufacture. For a high specific gravimetric energy density of a lithium-ion cell, the largest possible ratio between the stored energy and the weight of the housing is relevant. This can be achieved in particular by large-format housing concepts. The production and use of large-format lithium-ion cells is currently still associated with high challenges, both in terms of production and assembly technology as well as in safety and cooling of the cell stack.As part of the research activities, normative validation is investigated and safety concepts for large-format cells are developed both for production and storage as well as for further testing. Based on relevant and current standards such as UN T 38.3, ISO 12405-3 and SAE J2464, the specific suitability for large-format cells is analysed in order to determine the adaptation requirements of the individual standards in the next step. Due to the identified needs for improvement, the requirements of the test standards will be developed in close collaboration with institutions in the field of standardization. On the basis of a risk analysis of the product of the large-format cell compared to more classical cell formats, on the one hand the hazards can be estimated and on the other hand fields of action can be developed on the other.These challenges in the field of product safety are addressed in the InnoCase project in a consortium of industry and research that includes partners along the entire value chain of lithium-ion cell production. The focus is on the research and development of novel package concepts that contain only the advantages of conventional package types. Simplified cell assembly and improved module integration concepts are expected to reduce lithium-ion cell's production costs.