To keep the battery pack in an ideal performance range, reduce the aging behavior, and prevent thermal runaway of a battery cell and thermal propagation within the pack, an efficient thermal management is necessary. The strong competition on the market urges developers to closely link and parallelize the development process for the battery cell and the thermal management system. Especially for new upcoming cell technologies like next generation Lithium-Ion (LIB) and first Sodium-Ion Batteries (SIB) – both with either liquid or solid-state electrolytes – this poses a big challenge due to the scarce data base of thermophysical properties for those systems. To determine the effective parameters for specific heat capacity and density of batterie electrodes and cell stacks, mass- and volume fraction-based calculations can be a way to go, if the needed pure-material or effective transport data are available. The determination of the thermal conductivity of a porous electrode, however, is significantly more difficult because of the complex thermal transport paths through the heterogenous microstructure.

All in all, only few reliable and comprehensive thermophysical parameter sets can be found in literature for next generation LIB, first SIB and All-Solid-State Lithium Batteries (ASSLB) at the moment. This work focuses on reducing this gap by investigating and determining effective thermal conductivity, specific heat capacity and density of such new and upcoming battery materials, of pure substances as well as electrode sheets. In order to cover the large variety of possible configurations of the electrodes of future battery materials and to capture the influence of the individual composition and material parameters, a generic approach is chosen.

An inhouse analytical model, which was validated for material systems of established LIB, is used to determine the effective thermal conductivity. Based on a systematical literature review and inhouse measurements, calculations and simulations studies were performed to evaluate the composition- and bulk-material-data influence on the effective value of the porous electrodes and cell stacks of these battery systems. In addition, the possible variation ranges between the minimum and maximum of the thermophysical properties were evaluated depicting a possible spectrum in which the future battery materials can be located, providing a first orientation for the design of thermal management systems. Variation studies of the analytical model have been verified using an in-house three-dimensional numerical simulation model resolving the heterogenous electrode microstructure of active material, binder and electrolyte within the pores.