scholarly journals Preparation of SA–PA–LA/EG/CF CPCM and Its Application in Battery Thermal Management

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1902
Author(s):  
Ziqiang Liu ◽  
Juhua Huang ◽  
Ming Cao ◽  
Yafang Zhang ◽  
Jin Hu ◽  
...  

To improve the heat dissipation efficiency of batteries, the eutectic mass ratios of each component in the ternary low-melting phase change material (PCM), consisting of stearic acid (SA), palmitic acid (PA), and lauric acid (LA), was explored in this study. Subsequently, based on the principle of high thermal conductivity and low leakage, SA–PA–LA/expanded graphite (EG)/carbon fiber (CF) composite phase change material (CPCM) was prepared. A novel double-layer CPCM, with different melting points, was designed for the battery-temperature control test. Lastly, the thermal management performance of non-CPCM, single-layer CPCM, and double-layer CPCM was compared via multi-condition charge and discharge experiments. When the mass ratio of SA to PA is close to 8:2, better eutectic state is achieved, whereas the eutectic mass ratio of the components of SA–PA–LA in ternary PCM is 29.6:7.4:63. SA–PA–LA/EG/CF CPCM formed by physical adsorption has better mechanical properties, thermal stability, and faster heat storage and heat release rate than PCM. When the CF content in SA–PA–LA/EG/CF CPCM is 5%, and the mass ratio of SA–PA–LA to EG is 91:9, the resulting SA–PA–LA/EG/CF CPCM has lower leakage rate and better thermal conductivity. The temperature control effect of single-layer paraffin wax (PW)/EG/CF CPCM is evident when compared to the no-CPCM condition. However, the double-layer CPCM (PW/EG/CF and SA–PA–LA/EG/CF CPCM) can further reduce the temperature rise of the battery, effectively control the temperature and temperature difference, and primarily maintain the battery in a lower temperature range during usage. After adding an aluminum honeycomb to the double-layer CPCM, the double-layer CPCM exhibited better thermal conductivity and mechanical properties. Moreover, the structure showed better battery temperature control performance, while meeting the temperature control requirements during the charging and discharging cycles of the battery.

2021 ◽  
Vol 11 (2) ◽  
pp. 14-24
Author(s):  
Khin Yu Sett ◽  
Mi Sandar Mon

The present work is to investigate the thermal conductivity of the phase change material (PCM) of stearic acid (SA) by using the supporting material of expanded graphite (EG). The EG is used with the mass ratio of 10%, 15% and 20%. SA is commercial grade and the EG is formed by thermal method using natural graphite powder and crystalline zinc nitrate. The composite materials of (SA/10% EG, SA/15% EG and SA/20% EG) are prepared by direct impregnation method. Thermal conductivity of pure SA and composite PCMs are investigated by laboratory apparatus of heat transfer base unit TD1002. The thermal conductivity of the SA/10%EG composite PCM has been improved to 0.64 W/mK from that of SA (0.28 W/mK) with the percentage enhancement of 129%. To verify the morphology of the materials, scanning electron microscopy (SEM) analysis is utilized. The results show that the EG is formed in multilayers with pores in which stearic acid is well absorbed. The charging characteristics of pure SA, SA/10% EG and SA/15% EG for low temperature latent heat storage (LHS) system are studied experimentally. The system is applied for domestic water heating. The PCM is filled in a 33 mm diameter cylindrical copper tube and placed in hot water storage tank. The water is filled in tank from the top section through the distributor to uniform entry. The phase change phenomena of the PCMs are measured by inserting thermocouples at two layers of PCM tube. The result shows that the melting time decreases with the increasing mass ratio of expanded graphite in composite PCM. Although the melting time of both layers are nearly the same at the experiment of composite PCMs, the lower layer takes longer time than upper layer for pure PCM. The charging time is decreased by 67% for SA/10%EG and 79% for SA/15% EG composite PCM from that value of pure SA.


2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Ming Cao ◽  
Juhua Huang ◽  
Ziqiang Liu

This study introduces a new type of lightweight, shape-stable composite phase-change material (CPCM) to improve the thermal management of ternary lithium batteries. Paraffin wax (PW) was used as a phase-change material, expanded graphite (EG) and high-density polyethylene (HDPE) were used as support materials, carbon fiber (CF) was used as a heat-conductive additive, and a 3D printed aluminum honeycomb with a prickly structure (3D Al-Hc) was added to enhance the mechanical properties and thermal conductivity of the CPCM. The properties of the CPCM were analyzed based on its microstructure, thermal properties, and stress-strain response. The CPCM was applied to a battery cooling module to determine the temperature response of a battery. The results showed that when the CF mass fraction was 4.5 wt%, the degree of supercooling in the PW/EG/CF/HDPE was reduced by 51.5% and 43.3% compared to PW PCM and PW/EG CPCM, respectively. In addition, the thermal conductivity of the PW/EG/CF/HDPE/3D AL-Hc CPCM (5.723 W/(m·K)) was 1.9 times that of the PW/EG. Due to the presence of the 3D AL-Hc, the CPCM has a strain of 1.25 mm at a pressure of 100 KPa. In addition, the CPCM has excellent battery thermal management performance. At a 2.5°C discharge rate, the operating temperature of the battery is kept within the safe temperature range of 50°C.


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