## 1 Introduction
The immersion cooling of Li-ion batteries can be considered an emerging subject; thus, there is a limited number of studies on this subject. In studies on the immersion cooling of Li-ion batteries, the performance of immersion cooling is evaluated by comparing temperature results with other methods (such as indirect or air cooling). The experiments and numerical studies are performed using dielectric fluids or mineral oils under the same operating conditions, and the results are compared to distinguish the importance of immersion cooling. The immersion cooling of cylindrical batteries has been studied by different researchers [31; 32; 33; 34; 35; 36; 37]. [PERSON] et al. [31] performed experiments using Novce 7000 during pool boiling conditions and concluded that immersion cooling has superior thermal performance compared to air cooling. [PERSON] and [PERSON] [32] constructed a battery module with 60 cells and performed flow boiling experiments with HFE-7000. The results revealed that the maximum temperature and difference are approximately 38 \({}^{\circ}\)C and 4 \({}^{\circ}\)C, respectively, for a 5C discharge rate. [PERSON] et al. [33] numerically compared the performance of battery modules cooled with cold plate and immersion (Novce 7500) techniques. The researchers stated that the removal of heat from cells could be increased by approximately 32% at the discharge rate of 3C with immersion. [PERSON] et al. [34] experimentally and numerically investigated the heat rejection performance of batteries and revealed that flow rate has a significant impact on temperature. They also stated that the maximum temperature could be kept under 50 \({}^{\circ}\)C by using a low mass flow rate where it is necessary to increase the flow rate to obtain lower temperature differences. [PERSON] and [PERSON] [35] compared the thermal performance of three different dielectrics and air regarding temperature variation and pressure loss. They observed that the battery temperature increment could be kept at 2.2 \({}^{\circ}\)C during 3C, which is a very low value compared to other fluids tested. [PERSON] et al. [36] conducted experiments to cool batteries, and they stated that the temperature increments of batteries working with mineral oil are 4.4 \({}^{\circ}\)C and 5.4 \({}^{\circ}\)C with the application of free and submerged jets, respectively. [PERSON] et al. [37] performed immersion cooling experiments with SF33 fluid and air to investigate the temperature variation for various discharge rates and revealed that the temperature increment of batteries working with SF33 fluid and forced air are approximately 5 \({}^{\circ}\)C and 14 \({}^{\circ}\)C, respectively. As another geometric type, the immersion cooling performances of pouch/prismatic-type batteries have been performed by [38; 39; 40; 41; 42; 43; 44; 45; 46; 47; 48] in the literature. [PERSON] et al. [38] experimentally and numerically compared the cooling performance of various methods to investigate their effectiveness. Both jacket and oil cooling can be good solutions for the battery temperature rise problem. [PERSON] et al. [39] performed boiling experiments by submerging batteries into hydrofluoroether fluid and adding porous surfaces between pouch-type batteries to enhance heat transfer. They stated that the temperature of batteries could be kept under 40 \({}^{\circ}\)C, which is the upper limit in the desired temperature operating range. [PERSON] and [PERSON] [40] conducted experiments to research the immersion cooling of batteries submerged in water/ethylene glycol and evaluated the performance by comparing air results. They concluded that the average and maximum temperatures could be significantly decreased with the implementation of immersion cooling.