The prediction of thermal behavior is essential for an efficient initial design of thermal management systems which equip energy sources based on electrochemical cells. In this study, the surface temperature of various cylindrical types of Li-ion batteries is monitored at multiple points during discharge. Three different battery chemistries and two sizes (18650 and 21700) are considered in this study, allowing the comparison of the influence these parameters have on the temperature rise considering different discharge rates (1C, 2C and 3C). Based on repeated experimental measurements, a simple equation that describes the thermal behavior of batteries is proposed and further used to create 3D thermal maps for each analyzed battery (generally error is below 1 °C but never exceeds 3 °C). The practical utility of such an equation is that it can drastically reduce the time spent with experimental measurements required to characterize the thermal behavior of cylindrical Li-ion batteries, necessary for the initial design process of energy sources’ thermal management system.

Increasing electric vehicle (EV) adoption raises concerns about EV waste management and the impact on the environment. To improve energy efficiency and exploit their remaining usable capacity, the retired batteries may be repurposed in second-life applications. This paper predicts the usable second-life capacity of retired EV batteries, considering the European Union (EU) regulation regarding the mandatory recycled critical material quotas in newly manufactured batteries from 2031 onwards. Based on political influences and the market’s capacity to return to pre-pandemic values, four scenarios are proposed regarding future EV sales in the EU market. The algorithm implemented in Matlab R2025a indicates the batteries that must be recycled to meet the mandatory targets and the ones that can be repurposed as battery energy storage systems. Historical data and future predictions are used to determine the number of EV batteries sold, lifetime, the market’s chemistry share and the usable capacity for second life. The annual mandatory recycled critical material content is compared to the available recyclable mass from both retired batteries in the current year and those that are already active in their second life. The economic analysis reveals the scenario with the highest total revenue, including the cascade benefits and recycling value.

One of the obstacles to the adoption of electric vehicles as a future pollution-free transport solution is that the energy sources (batteries) have not yet become sustainable through a long-life span under the specific operating conditions. The problem that arises is that high temperatures inside the batteries represent a safety risk and have negative effects on the battery life span, which imposes the use of thermal management systems. The present article aims to analyze, by numerical methods, the effect of the use of a fireproof composite resin on the efficiency of the thermal management system, specifically on the degree of battery sustainability (measured by the effect on the life span). Five constructive variants are proposed and thermally analyzed. Based on the measured temperatures, the intensity of the chemical reactions that occur in a 18650-type Li-ion cell was calculated, and conclusions related to the impact on the life span were drawn. It has been found that the use of a fireproof composite resin leads to an increased heat transmission towards the outer environment and an increase in the life span by 22.2% compared to that noted for conventional air cooling. The results also recommend the use of heat exchangers associated with flame retardant resins, which leads to a 20.6% improvement in the heat transfer capacity of the battery’s thermal management system. When comparing the solutions in which the flame-retardant resin is used, the results show that adding 3 wt.% of nanomaterial leads to a significant life span increase of 11.7% when compared to the results for the resin-only case.

The paper presents a numerical analysis of the possibilities of replacing the aluminum serpentines in the current construction of battery thermal management systems (BTMS) with cooling serpentines made of fireproof composite materials with high heat transfer parameters (fireproof epoxy resin + nano boron nitride). This approach was given by the need to replace aluminum (which, in case of fire, maintains and accelerates the combustion process) with fireproof materials that reduce/eliminate the fire risk due to improper battery operation. Numerical analysis methods were used through simulation to identify the most efficient design among the single-channel, multichannel, multiflow and multiple coolant inlet–outlet solutions for cooling serpentine. In addition to these geometric constructive parameters, the variation of the coolant flow rate (9, 12, 15 and 18 L/min) and coolant inlet temperature (17, 20 and 25 °C) was also considered. The obtained results showed that the single-inlet nanocomposite resin cooling serpentine four-channel configuration presents the highest cooling efficiency of the cells that form the battery module while ensuring very good thermal uniformity as well. These findings are supported by the lowest average heat absorption by the batteries, of 34.44 kJ, as well as the lowest average internal resistance difference (caused by thermal gradients), of 5.23%. Future research is needed to identify the degree of structural resistance of serpentines made of fireproof composite material to external stresses (vibrations characteristic of the operation of electric vehicles).

The increasing number of new battery electric vehicle (BEV) registrations worldwide and the development of advanced batteries with higher energy density and pack capacity have contributed to large volumes of batteries approaching the end of their first service life. The retired batteries may be repurposed in second-life applications or recycled. The degradation profile of BEVs is a critical determinant in second-life potential of the retired batteries. This study presents a comprehensive analysis of calendar and cycle mechanisms in lithium iron phosphate (LFP) and nickel manganese cobalt oxide (NMC) batteries across 37 commercially available BEV models in the European Union (EU) market. Three scenarios are considered, based on the operational temperature—Scenario I with a 273.15 K, Scenario II with a 298.15 K, and Scenario III with a 318.15 K operational temperature—and two degradation metrics are determined for each analyzed BEV: state-of-health (SoH) and remaining capacity at end-of-life (EoL). The results show that the SoH of both chemistries is highly dependent on the state-of-charge (SoC), temperature, depth of discharge (DoD), and real usable capacity. Moreover, the Tesla Model 3–Premium RWD, Volkswagen ID.3, ID.4, and ID5–GTX, and the Tesla Model Y–Premium AWD all exhibit a remaining capacity between 40 and 77 kWh at EoL, depending on degradation profile, making them a viable option for second-life applications.