After the definition of CoFBAT’s use cases and expected Key Performance Indicators (KPIs), it was time for the next step and to define the reference cells and specific tests and parameters for cell and material components. The report Cell requirements describes detailed cell requirements containing electrical-, safety- and lifetime requirements (based on the use cases and KPIs).
A close collaboration between material-suppliers (Solvay, TOPSOE, CEA, IFE and Torrecid), cell developer Cidetec and cell manufacturer Varta Micro Battery, led to robust requirements.
The necessary requirements from the system point of view were defined, including important characteristics of the cell like:
- specific energy;
- volumetric energy;
- power density;
- C-rate capability, and internal resistance;
- operation limits regarding voltage and temperature;
- calendar lifetime;
- cycle lifetime;
- safety requirements.
Together with the cell manufacturers Varta Micro Battery and Varta Micro Innovation, the cell requirements were checked, which resulted in an associated report on Material and components.
The outcome of the cell requirements provided information for the required materials specifications that are necessary to allow the construction of cells. The objective was to translate the cell requirements into two sets of requirements:
1: The set of requirements that each cell component need to be fulfilled in the battery configuration “LNMO/Si-C”.
2: The set of reequirements that each cell component need to be fulfilled in the battery configuration ‘LNMO/TN”.
It became clear that all the questions raised by the translation of the cell requirements into materials and components cannot be completely solved for all the expected properties at cell levels.
Accordingly, the report on ‘material and components’ represents the synopsis of the demanded properties on material level. For this purpose, the document includes in detail the properties the material must fulfil to meet the cell requirements regarding energy density, component interactions and interface management.