In this article, a combined experimental and analytical study has been performed to 12 investigate the transient heat generation characteristics of the lithium-ion power battery. An 13 experimental apparatus is newly built and the investigations on the charge/discharge 14 characteristics and temperature rise behavior are carried out at the ambient temperatures of 28 o C, 15 35 o C and 42 o C over the period of 1C, 2C, 3C and 4C rates. The thermal conductivity of a single 16 battery cell is measured, which is 5.22 W/(m·K). A new model of the heat generation rate based 17on the battery air cooling system is proposed by the lumped parameter approach. Comparison 18 between the simulated battery temperatures with experimental data is performed and good 19 agreement is achieved. The impacts of the ambient temperature and charge/discharge rates on the 20 heat generation rate are further analyzed. It is found that both ambient temperature and 21 charge/discharge rates have significant influences on the voltage change and temperature rise as 22 well as heat generation rate. During charge/discharge, the larger the current rate, the larger the 23 heat generation rate. The effect of the ambient temperature on the heat generation shows an 24 obvious difference with different state of charge. 25 26 Keywords: Lithium-ion battery; heat generation model; heat generation rate; temperature rise; 27 thermal management system 28 29 51 52 Subscripts 53 amb ambient 54 h convection heat transfer 55 J Joule heat 56 max maximum 57 t time 58 v volume 59 Acronyms 60 DC direct current 61 DOD depth of discharge 62 EV electric vehicle 63 HEV hybrid electric vehicle 64 ITMS integrate thermal management system 65 TMS thermal management system 66 TPS transient plane source 67 SOC state of charge 68 69 1. Introduction 70 Among the electrochemical energy storage systems, lithium-ion batteries, as a promising 71 candidate, have attracted considerable attention in many power demand applications due to their 72 advantages of large specific energy, high power density, charge/discharge cycle stability and long 73 cycle lifetime [1, 2]. With rapid development of the electric vehicles (EVs) and hybrid electric 74 vehicles (HEVs), lithium-ion batteries have been widely used in recent years [3]. However, a 75 large amount of heat will be generated because of the electrochemical reactions and physical 76 changes inside the batteries, potentially bringing out capacity fade and thermal runaway [4]. 77Therefore, it is crucial to have insight into the heat generation characteristics for maintaining 78 safety and performance of the battery. 79Many researches on the safety issues of the battery are finally ascribed to the heat generation 80 and heat dissipation at each level of the battery system [5, 6]. In order to keep the battery within 81 a reasonable temperature, an efficient thermal management system (TMS) will be needed to 82 dissipate the heat generated. Furthermore, the heat generation rate is a necessary prerequisite for 83 an efficient TMS design [7, 8]...

In some special circumstances such as building envelope, Traditional cooling methods can not meet the requirements of safety, stability, reliability and energy saving. In Part I of this study, a new conjugate cooling method of Phase Change Material (PCM) combined with Pre-cooling of Building Envelope (PBE) is proposed and the numerical model of PBE are developed. In the current study, a refuge chamber is selected as a case study. A semi-analytical method is used to analyze the cold storage performance of the surrounding rock (SR). Afterwards, a numerical simulation model of the coupling cooling system, which take the heat source, SR, PCM and air heat transfer into consideration, is further established. The study identified that the simplified semi-analytical calculation formula with the diagram of the cold storage quantity of SR are very helpful for engineering calculation. The influence of the Fourier and Biot number on the cold storage capacity of SR can be easily analyzed. In addition, the whole-field model of the conjugate cooling system is completely developed based on the PCM unit. Part II will involve a parametric assessment and the optimization of the conjugate colling method will be explored.

No abstract

No abstract

, 'Experimental and numerical investigation on integrated thermal management for lithium-ion battery pack with composite phase change materials', Energy