Energy Storage最新文献

Various heat transfer augmentation techniques have been investigated to address the low thermal conductivity nature of phase change materials (PCMs). However, the techniques may also accelerate the heat exchange between the system and its surroundings, which increases the heat leak into the system during the cold holding process, particularly in prolonged cold thermal energy storage (CTES) systems. Hence, comprehensive evaluation is crucial for researchers to develop enhancement techniques that enable faster charging and slower discharging rates. This review comprehensively evaluates different passive heat transfer enhancement techniques, including fin addition, storage container optimization, nanomaterial dispersion, metal foam embedding, and hybrid methods. It identifies enhancement methods and their key parameters and factors favorable for prolonged CTES systems, based on their distinct impacts on the melting and solidification rates. The review reveals that incorporating nanomaterials at higher concentrations, metal foams with lower porosities, and convective flow restricting fins demonstrate higher solidification and slower melting rates, resulting in faster charging and prolonged cold retention durations. In contrast, adding fins that facilitate natural convection and embedding metal foams with higher porosities exhibit comparable melting and solidification rates. Additionally, the review includes performance limitations and life-cycle aspects of enhanced PCMs. Moreover, various techniques, including spatiotemporal PCMs, form-stable cold thermal energy storage phase change materials (FCPCMs), and double-layer insulations, significantly improve the cold retention duration of PCMs used in long-term CTES systems. It also highlights the challenges and future prospects, focusing on developing phase change CTES systems for prolonged cold storage, emphasizing performance, cost-effectiveness, scalability, and sustainability.

To mitigate the volatility associated with renewable energy generation, energy storage technologies are essential for shifting energy across time and space by capturing surplus electricity and discharging it during deficits. This capability is vital for enhancing energy efficiency and facilitating the extensive integration of renewables. This study develops and evaluates two Advanced Adiabatic Compressed Air Energy Storage (AA-CAES) configurations: a three-stage compression/expansion system and a four-stage counterpart, both designed for an 8-h charge and 4-h discharge cycle. Thermodynamic and economic models were constructed to assess their performance. The simulation indicates that the three-stage system achieves a round-trip efficiency (RTE) of 76.20% and an energy generation per unit volume (EGV) of 6.67 kWh/m³, leaving 207.88 tons of residual hot water. In comparison, the four-stage system shows a slight decline in RTE by 1.23% and EGV by 0.41 kWh/m³, but generates a significantly higher surplus of hot water (increased by 171.82 tons). Economically, the levelized cost of energy (LCOE) is 0.1067 $/kWh for the three-stage system and 0.1104 $/kWh for the four-stage system, with dynamic payback periods (DPT) of 1.6 and 1.7 years, respectively. To address the substantial hot water surplus in the four-stage design, an Organic Rankine Cycle (ORC) was integrated for waste heat recovery. This integration improved the system's work capacity, RTE, and EGV. Although the initial capital expenditure rose due to additional equipment, the slight dip in economic metrics is negligible compared to the thermodynamic gains.

This study examines the thermal behavior of Li-ion batteries (LIB) under high discharge rates, emphasizing the necessity of an efficient battery thermal management system (BTMS) employing phase change materials (PCMs). Without any thermal regulation, the battery temperatures rose sharply to 66.16°C, 74.8°C, and 82.40°C at 3C, 4C, and 5C discharge rates, respectively—well above the safe operating threshold. Incorporating a PCM-based BTMS significantly mitigated this rise, lowering the maximum temperatures to 29.69°C, 30.74°C, and 31.78°C, corresponding to reductions of approximately 55.12%, 58.91%, and 61.43%. Among the four PCMs tested (RT-28, RT-31, RT-33, and RT-35), RT-28 demonstrated superior thermal performance, exhibiting the lowest temperature rise and the highest energy absorption (1.9 kJ at 5C), compared to RT-31 (1.7 kJ). At 5C, RT-28 achieved a liquid fraction of 51.17%, while RT-31 reached a liquid fraction of 44.48%. Over time, thermal resistance increased for RT-28, RT-31, and RT-33, with RT-31 peaking at 3.95 mΩ, whereas RT-35 remained nearly constant at 3.80 mΩ. These results highlight that selecting PCMs with phase change temperatures closely matching the battery's operational range can effectively enhance safety, suppress thermal runaway, and improve performance in high-power applications such as electric vehicles (EVs) and renewable energy systems.

Sodium-ion batteries (SIB) exhibit enormous application potential in energy storage applications due to their abundant sodium resources, low cost, and superior low-temperature rate performance. However, public reports on the study of thermal runaway (TR) coupled with gas generation characteristics in SIB remain relatively limited. This study conducts a comparative investigation into the TR and gas generation characteristics of SIB, lithium iron phosphate (LFP)/graphite batteries, and nickel-cobalt-manganese/graphite batteries (NCM). The study quantifies the gas volume and composition generated during TR of the three battery types and employs the Analytic Hierarchy Process (AHP) to compare the disaster risks of TR in SIB, LFP, and NCM. The results show that at the same state of charge (SOC), SIB and NCM exhibit lower TR onset temperatures but significantly higher instantaneous pressures than LFP. Their gas production is approximately 2.84 and 2.72 that of LFP, respectively, posing greater challenges for gas-induced disaster prevention at the system level. The gas compositions during TR are similar across the three systems, with LFP showing higher H₂ content and lower CO/CO₂ content. SIB and NCM have higher lower explosive limits (LEL), lower upper explosive limits (UEL), and narrower explosive ranges, indicating lower explosion risks. Comprehensive evaluation suggests that SIB and NCM present lower overall hazard levels than LFP under the same SOC, though risks in certain characteristic parameters cannot be ignored. These findings are expected to provide references for the safety design of large-capacity multisystem batteries, thereby enhancing their safety in commercial applications.

High performance Sr_1−xGd_xTiO₃ (x = 0–0.030) GST ceramic capacitors were prepared by ball milling and sintering. Phase structure and microstructure were explored, the dielectric characteristics dependence was studied in relation to frequency and temperature, high voltage breakdown testing, and PE testing were also carried out. By Gd doping at different compositions, lattice contraction/expansion occurred depending on the substitution sites of Gd³⁺ ions. By Gd doping, the single cubic perovskite structure was retained, and the grain structure was refined by doping with Gd³⁺ ions. A good set of dielectric properties was achieved for 2.0 GST, which included a very high dielectric constant of 4800, high capacitance of 1500 pF, low dielectric loss of 0.05 with good break-down strength of 5.12 kV/mm, and highest volumetric energy density of 558 kJ/m³.

Increasing demand for fast charging in electric vehicles requires battery cooling. This research article explored the outcome of air cooling and phase change material (PCM) on battery thermal management at several charging rates. Initially, the numerical investigation was carried out on two different models of the air and PCM (paraffin wax, n-eicosane, and copper foam) cooling. Outcomes of the air-cooling show that air cooling is not feasible for higher charging rates, especially more than 2 C. Consequently, response surface methodology was used to determine the consequence of air inlet velocity, air inlet temperature, and charging rates on the temperature of the battery pack. The optimum conditions for air cooling are heat generation 42 102 W/m³, air inlet velocity 0.5 m/s, and inlet air temperature 20°C, for which the responses are, namely, maximum cell temperature 332.62 K, cooling efficiency 9.73%, pressure drop 6.53 Pa, and outlet air temperature 313.92 K. The copper foam gives a lower temperature and also maintains uniformity in the maximum cell temperature as associated to other PCM. The PCM materials fail to cool all the cells uniformly due to the lesser thermal conductivity of the PCM materials. The current simulation study validated with the experimental study of previous researchers, which shows that the copper foam gives better performance than the composite PCM. At 50 min of charging, the copper foam and CPCM enhance the maximum cell temperature up to 66°C and 71°C. The copper foam performed best at the 3 C charging with 50 min, at which the maximum cell temperature was 339 K.