Simplification strategy research on hard‐cased Li‐ion battery for thermal modeling

Abstract

Summary Numerical simulation is widely used in research and design of the battery thermal management system (BTMS). Battery cells are commonly homogenized to a block for module or pack level modeling. However, how the homogenization method affects results is not proven. This paper works on a hard‐cased Li‐ion battery to find a proper simplification method. First, a detailed three‐dimensional thermal model (model A) is set up and validated by experimental data. Then, the other three models with different simplification strategies are proposed. They are model B (the cell is homogenized to a block), model C (the cell preserves only core region and housing case), and model D (based on model C, the thin insulation films are also considered). Take the results of model A as a reference, the calculation accuracy and efficiency are summarized. It is found that model B shows the best efficiency and is a proper choice for evaluation of temperature dynamics, while model D is more recommended when the internal temperature distribution of the battery is more concerned.

Impact of the Level of Homogenization in 3D Thermal Simulation on the Internal Temperature Distribution of Li‐Ion Battery Cells

“…The tab, the outer separator, and the pouch foil, respectively casing, are resolved in every simulation case, as it is necessary to increase accuracy. [ 13,15 ] The focus of this contribution is on the level of homogenization (LoH) of the cell stack. The most realistic representation of the inner structure of a cell stack on electrode level is to resolve each individual layer (FR model).…”

“…This results in a high computing time, which will be discussed for the studies conducted in Section 3.3. Therefore, as already mentioned in Section 1, it is common to fully homogenize the cell stack (FH model) [ 13,14 ] and assign effective parameters according to the volumetric fraction for simulation (cf. Section 2.4).…”

“…The homogenization of the geometry can be divided into two parts—the external components such as tabs, connectors, and housing, and the inner cell stack or jelly roll structure. Cui et al [ 13 ] performed a 3D thermal simulation on a hard case cell with a homogenized cell stack. If the internal temperature field is of interest, they suggest resolving the housing and the outer separator as a thermal contact resistance.…”

Effective Thermal Conductivity of Lithium‐Ion Battery Electrodes in Dependence on the Degree of Calendering

“…As the measurement of the temperature within the cells still poses a great challenge and the effects of inline measurement devices on the electrical cell behavior are not yet fully understood, [14,15] modeling is crucial to estimate the core temperature of the cells. However, those models are based on a lot of assumptions like the homogenization of the transport properties of the whole battery stack [16][17][18] and the neglection of contact resistances. Moreover, they are difficult to validate [15] and DOI: 10.1002/ente.202300259…”