Analytical Dissection of an Automotive Li-Ion Pouch Cell

Abstract

Information derived from microscopic images of Li-ion cells is the base for research on the function, the safety, and the degradation of Li-ion batteries. This research was carried out to acquire information required to understand the mechanical properties of Li-ion cells. Parameters such as layer thicknesses, material compositions, and surface properties play important roles in the analysis and the further development of Li-ion batteries. In this work, relevant parameters were derived using microscopic imaging and analysis techniques. The quality and the usability of the measured data, however, are tightly connected to the sample generation, the preparation methods used, and the measurement device selected. Differences in specimen post-processing methods and measurement setups contribute to variability in the measured results. In this paper, the complete sample preparation procedure and analytical methodology are described, variations in the measured dataset are highlighted, and the study findings are discussed in detail. The presented results were obtained from an analysis conducted on a state-of-the-art Li-ion pouch cell applied in an electric vehicle that is currently commercially available.

In Situ Measurement of Orthotropic Thermal Conductivity on Commercial Pouch Lithium-Ion Batteries with Thermoelectric Device

“…The nominal dimensions of one battery are 290 mm × 216 mm × 8 mm with a total weight of about 800 g. Regarding the chemistry, graphite is used as an anode material, whereas the choice for the cathode material is a spinel of NMC and LMO. More details about the battery type under test can be found in the work of [11]. In Figure 2, the reference system used as reference for each measurement direction is shown.…”

“…For the measurements, three battery samples were used. The battery samples were obtained from disassembling a complete battery pack; the complete procedure can be found in the work of [11]. The samples were all fresh (none with electrical ageing) and from the same battery pack.…”

Thermal Conductivity in Aged Li-Ion Cells under Various Compression Conditions and State-of-Charge

“…The cell used in this study is a 41 Ah Li-ion pouch cell with a nominal voltage of 3.7 V, which was obtained by dismounting the battery pack of a commercially available electric vehicle [24]. Regarding the single cell, the electrodes stack consists of 42 polypropylene tri-layer separators, coated with β-Al 2 O 3 on the anode side, sandwiched between 21 LiNiMnCoO 2 -LiMn 2 O 4 (NMC-LMO) cathodes and 22 graphite anodes.…”

Perspective on Commercial Li-ion Battery Testing, Best Practices for Simple and Effective Protocols

“…This will require multiple apparatus and thus details are out of the scope of this publication. The range of post-mortem tests proposed in the literature is wide [11,12,99] and some techniques might require a lot of resources. They are typically performed by opening the aged cells to test individual electrodes but some can be performed on full cells [11].…”