Preparation of Binary Thermal Silicone Grease and Its Application in Battery Thermal Management

Abstract

To improve the problems of large interface thermal resistance and low heat dissipation efficiency in battery thermal management (BTM), this paper uses methyl silicone oil as the matrix, AIN, copper powder (CP), and carbon fiber (CF) as thermally conductive fillers, and acetone and stearic acid as particle surface modification components. A variety of binary thermal silicone greases (TSGs) with different compositions were prepared. Different instruments were used to test the material properties of TSGs, and a better TSG was selected to coat the interface between battery and phase change material (PCM) for battery charging and discharging experiments. Through the analysis of experimental data, it was found that among the TSGs made of three mixed fillers (AIN/CP, AIN/CF, CP/CF), the three TSGs had good thermal stability, and their thermal degradation temperature both exceeded 300 °C. As the ratio of thermally conductive filler was gradually changed from 5:1 to 1:5, the TSG containing CP/CF had higher thermal conductivity and lower volume resistivity, while the TSG containing AIN/CF had the least damage due to interface wear. The acidification treatment of thermally conductive filler can improve the adsorption and compatibility of thermally conductive particles and silicone oil, and reduce the oil separation rate of TSGs. The prepared expanded graphite (EG)/paraffin wax (PW) composite phase change material (CPCM) has a relatively large latent heat of phase change, which can effectively control the temperature of the battery, but coating TSG between the battery and the CPCM can further enhance the heat dissipation effect of the battery.

Dry-Contact Thermal Interface Material with the Desired Bond Line Thickness and Ultralow Applied Thermal Resistance

“…Now, considerable attention has been paid to the development of high- k materials, and many attempts at highly thermally conductive TIMs have been witnessed in the past two decades. − For example, carbon nanotubes (CNTs) are the ideal TIM precursor due to their one-dimensionally highly thermo-conductive characteristic (≥2000 W/m K) . Various vertically aligned technologies were adopted to successfully fabricate perpendicular CNTs-array TIMs, whose out-of-plane k were reported to be able to exceed 70 W/m K. , Similar results can also be found in vertical graphene TIMs, for example, a mechanical-machining processed graphene monolith was manifested to exhibit an out-of-plane k as high as 143 W/m K, which is on par with some metals and alloys. , In addition to the above high- k carbons, other TIMs include liquid metals, ,, inherently thermally conductive polymers, polymer composites (i.e., thermal grease, gel, and pad), − and phase change materials. − Looking at the previously reported TIMs, the manipulation of the anisotropic k and making it superb in the thickness direction is not a very difficult thing; however, the achievement of a low R eff when these TIMs are applied in a sandwiched heat source-sink structure remains a formidable challenge. Taking one of the most mature and commercial dry-contact TIMs (thermal grease) as an example, its applied thermal resistance in a sandwiched structure is rarely found to be lower than 5 mm 2 K/W, a boundary value that traditional solders can perform .…”

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

“…Notably, the DFT theory developed by Rivelino et al [ 25 , 26 ], i.e., the synthetic growth method, is effective for the in-depth analysis of material stability and possible chemical reactions, and it has been applied to complex systems. In addition, although PW/EG/CF and SA–PA–LA/EG/CF CPCMs were involved in this study, the author has performed the application and material characterization of CPCM based on PW/EG many times in previous studies [ 27 , 28 , 29 ]; therefore, the characterization test materials involved in this study mainly included the SA–PA–LA ternary eutectic PCM and SA–PA–LA/EG/CF CPCM.…”

Siloxane‐Based Organosilicon Materials in Electrochemical Energy Storage Devices

“…Currently available TIMs include filled‐polymer matrices, thermal grease/pastes, phase change materials, and solders [75] . Among them, silicone material made of siloxane is a cost‐effective, high‐safety kind of TIM with flexibility, good insulation, and high resilience, which has been applied in lightweight, high‐strength, and high‐heat‐dissipation pouring sealant for battery packs and electronic devices [76] . Silicone matrices not only provide the necessary thermal conductivity, but also increase the contact surface between the batteries and the thermal conductive parts, effectively avoiding the risks of short‐circuiting and problems of vibration friction damage between the cells.…”