Challenges and recent progress in thermal management with heat pipes for lithium-ion power batteries in electric vehicles

Electric vehicles(EVs) are globally undergoing rapid developments, and have great potentials to replace the traditional vehicles based on fossil fuels. Power-type lithium-ion batteries(LIBs) have been widely used for EVs, owing to high power densities,good charge/discharge stability, and long cycle life. The driving ranges and acceleration performances are gaining increasing concerns from customers, which depend highly on the power level of LIBs. With the increase in power outputs, rising heat generation significantly affects the battery performances, and in particular operation safety. Meanwhile, the cold-start performance is still an intractable problem under extreme conditions. These challenges put forward higher requirements for a dedicated battery thermal management system(BTMS). Compared to traditional BTMSs in EVs, the heat pipe-based BTMS has great application prospects owing to its compact structure, flexibility, low cost, and especially high thermal conductivity. Encompassing this topic, this review first introduces heat generation phenomena and temperature characteristics of LIBs. Multiple abuse conditions and thermal runaway issues are described afterward. Typical cooling and preheating methods for designing a BTMS are also discussed. More emphasis on this review is put on the use of various heat pipes for BTMSs to enhance the thermal performances of LIBs. For lack of wide application in actual EVs, more efforts should be made to extend the use of heat pipes for constructing an energy-efficient, cost-effective, and reliable BTMS to improve the performances and safety of EVs.     

玛丽亚别墅解析

通过实地考察、图解分析玛丽亚别墅,从时代背景、空间、几何特征、非标准化以及细部处理等方面对其进行深入剖析,以进一步丰富国内建筑师的设计思想与方法.     

建筑火灾中人的有效逃生和消防器材的应用

有效逃生是建筑防火的核心命题 有效逃生概念的提出 消防技术产品的发展体现在硬件上的极大丰富和完善。这主要是指增加阻燃材料在建材中的应用，能够显著提高建筑本身的防火能力，在不超出阻燃材料所能承受的火灾荷载前提下，保证建筑的稳定性；另一方面，配备消防和防火工程系统，增加建筑防火器材，保证建筑在火灾中的稳定；第三方面，要增加建筑内部居住和使用人员对火灾的认知程度，使建筑消防技术得以在真正意义上的体现。     

利用Modbus协议实现无线通信

本文介绍了Modbus的控制网络及协议特点．着重分析Modbus ACSⅡ模式的消息帧组成、校验码的计算及主要的功能。并对利用Modbus协议实现远程无线通信的有关要点作了说明。     

Synthesis of γ-Bi2O3/YSZ composite powders using a facile precipitation method

Low melting point and high ionic conductivity of γ-Bi₂O₃ make it a promising additive to decrease the sintering and operation temperatures of yttria stabilized zirconia (YSZ)-based electrolyte for solid oxide fuel cell application. Herein, γ-Bi₂O₃/YSZ composite powders with good uniformity and precise control of morphology and phase were successfully synthesized via a low cost chemical precipitation method. Both the concentration of NaOH solution and the reactant adding sequence affect the morphology and synthesis of γ-Bi₂O₃/YSZ composite powders. When the concentration of NaOH was in the range of 1.25–1.875 M, tetrahedron γ-Bi₂O₃/YSZ powders were synthesized. While, cubic structural γ-Bi₂O₃/YSZ powders were obtained when adding Bi³⁺ and YSZ suspension into 1.5 M NaOH solution. The addition of YSZ facilitates the fabrication of γ-Bi₂O₃ and widens its process window to a higher NaOH concentration. Thus synthesized γ-Bi₂O₃/YSZ composite powders effectively decrease the sintering temperature of YSZ to 1050°C due to the uniform distribution of γ-Bi₂O₃ inside YSZ powders. This work provides a facile method to fabricate γ-Bi₂O₃/YSZ composite powder with controlled morphology and phase, which will promote the mass production of low cost YSZ-based electrolyte for SOFC applications.     

Erosion wear experiments and simulation analysis on bionic anti-erosion sample

The dorsal surface of a desert lizard has excellent particle erosion resistance.In this paper,a bio-inspired sample was designed and fabricated based on the biological characteristics of the dorsal skin of the desert lizard(Laudakin stoliczkana).The bionic sample consists of two materials with different characteristics,which form a two-layer composite structure.The particle erosion property and erosion wear mechanism of the bionic sample was studied by means of sandblast experiment and numerical simulation,respectively.The experimental results show that,in the stage with steady abrasion rate,the weight loss per unit time of the bionic sample is about 10%lesser than the control sample.The numerical simulation indicated that the two-layer structure of the bionic sample can efficiently absorb the normal stress,and dissipate the stress in the horizontal direction.Thus,the stress concentration on the sample surface is suppressed.The two-layer structure is contributed to the decentralizing of the stress distribution,and thus the occurrence probability of erosion damage can be decreased.     

CuO nanoflowers/copper fiber felt integrated porous electrode for lithium-ion batteries

Science China Technological Sciences - The structure of current collectors has significant effects on the performance of a lithium-ion battery (LIB). In this study, we use copper fiber felts made...