As has been demonstrated very clearly in recent years, the problem of short circuiting and overheating of the battery could not be identified at the time the battery was in production. Only after a prolonged cycle (use) can this phenomenon occur. The market forces battery manufacturers to extend battery life, achieve higher energy densities and faster charging times. This will force engineers to design higher density electrodes and use thinner, more porous separators. The fact is that energy densities are double what they were five years ago using the same materials. The battery separator plays an important role by regulating cell kinetics, allowing ion flow, preventing electronic contact between the two electrodes, and sometimes acting as a safety device. Since the separator is pressed between the two electrodes and filled with electrolyte, it is in contact with all the active components of the cell. By regulating electrolyte distribution, it limits ion diffusion and recombination rates and therefore has a significant impact on cell capacity, cell power and available energy. As a result, much work has been done to determine optimal separator characteristics, such as porosity and tortuosity.1-3 Separator degradation has often been observed in some types of batteries and has been shown to be responsible for battery failure or leakage. of power. [R Kostecki, L Norin, X Song, F McLarnon, Diagnostic studies of polyolefin separators in high-power lithium-ion cells. Journal of the Electrochemical Society (2004) Vol. 151 (4) pp. A522-A526]1 Therefore, higher energy density (higher pressure on the separating polymer film) and higher power (wide temperature range within the cell generated by the applied current) and longer cycle life (>10 years for the industry automotive). ..... half of the sheet ......m rooms, due point -45). HTI measurements were performed in the Teflon apparatus with stainless steel electrode (diameter – 12 mm) placed on the hot plate and connected with Solartron 1255B (frequency response analyzer) (as above). The temperature range from 50 to 200 oC was controlled at an average rate of 10 oC/min. (the reason why it's so fast...) The performance of lithium ion cells (assembled with 18650 coated separator and aluminum pouch cells) such as charging/discharging characteristics and cycling capacity have been studied with the Bitrode battery tester.3. Results and discussion Data on ionic conductivity and MacMullin number of coated and uncoated separators are provided in Table 2. Asahi (PE) and Degussa (PET/ceramic) are also listed for reference. Table 2 Ionic conductivity of separators and MacMullin number (Nm) (electrolyte: 1M LiPF6 in EC:EMC; conductivity - 9.1 mS/cm)