Method for Determination of the Internal Short Resistance and Heat Evolution at Different Mechanical Loads of a Lithium Ion Battery Cell Based on Dummy Pouch Cells

Abstract

Within the scope of developing a multi-physical model describing battery behavior during and after the mechanical load (accelerations, intrusions) of a vehicle's high voltage battery, an internal short circuit model is of deep interest for a virtual hazard assessment. The internal short resistance and the size of the affected area must be known as a minimum for determining the released heat and, in consequence, the temperatures. The internal short resistance of purpose-built dummy pouch cells, filled with electrolyte-like solvent without conductive salt, has thus been measured in a given short area under various compressive loads. The resistances for different short scenarios obtained are analyzed and described in a mathematical form. Short circuit experiments with dummy cells using an external power source have also been carried out. This setup allows the measurement of the temperature evolution at a known current and a determination of the actual short resistance. The post-mortem analysis of the samples shows a correlation between the maximum temperatures, released short heat and the separator melt diameter.

Electrical and thermal interplay in lithium‐ion battery internal short circuit and safety protection

“…The size is 17 cm *23 cm (width*length) and the capacity is 1.2 Ah. It is supposed that the anode‐aluminium short‐circuited resistance is about 15 mΩ, while the anode‐cathode short‐circuited resistance is about 500 mΩ 16,19,25 . The maximum temperature at the ISC spot and voltage variation are illustrated in Figure 4.…”

“…Apart from the material modification method, detection and diagnosis 15 are of great significances in enhancing the safety and reliability of battery. Usually, specific parameters such as SOC (state of charge), voltage, temperature and resistance are detected to predict or estimate the risk of thermal runaway 16,17 . But this method depends much on the accuracy of parameter estimation.…”

Cause and Mitigation of Lithium-Ion Battery Failure—A Review

“…For Al–An, Figure 9 d shows that for force values above 20 N, the particles exhibit good accordance with the ~100 m ohm. Finally, we can summarize that electrolyte can influence the resistance of Lithium Ferrous Phosphate [ 135 , 136 , 137 ]. The mechanical mode of failure is thus regarded as the initiator or propagator of the electric and thermal modes that are discussed in the following sections.…”

Electric Vehicle Fire Extinguishing System

“…The reference value threshold, for opening the electromagnetic valves can be independently set for each of the protected powertrain elements: battery temperature T B >90°C, motor temperature T M >150°C, inverter temperature T I >100°C, charger temperature T Ch >100°C. The temperature threshold values were selected basing on thermal characteristics of lithium cells [18,19,20]. Each type of chemical battery, including lithium based cells, is subjected to self-heating which can be in simplification treated as proportional to the product of squared current flowing through the cell and the cell's internal resistance.…”