Experimental and analytical study on heat generation characteristics of a lithium-ion power battery

Abstract

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]...

A comparative study on the degradation behaviors of overcharged lithium‐ion batteries under different ambient temperatures

“…Similar to the results under 20°C, all the battery capacities exhibit obvious degradation during the overcharge cycling, and the severity worsens under the high CCV condition. 23 Whereas, with the continuation of overcharge cycling, batteries ultimately experience degradation, and degradation rates of 0.04 and 0.06 %/cycle are exhibited, respectively. The degradation behavior of the battery overcharged to 4.5 V is much more gentle exhibiting a degradation rate of 0.04 %/cycle.…”

An integrated framework for minimization of inter lithium‐ion cell temperature differences and the total volume of the cell of battery pack for electric vehicles

“…It is well known that the lithium‐ion can only work at a narrow temperature window to maintain higher performance. Based on the study of, the Joule heat generation will increase with the environment temperature decrease to a low value, such as 5°C. However, when the temperature was increased from 25°C to 45°C, the total heat generation was decreased because of the reduction of the Joule heat.…”

“…It is well known F I G U R E 4 Classification of heat generation source and place of lithium-ion batteries F I G U R E 5 Heat generation influence factors of lithium-ion battery that the lithium-ion can only work at a narrow temperature window to maintain higher performance. Based on the study of, 17 the Joule heat generation will increase with the environment temperature decrease to a low value, such as 5 C. However, when the temperature was increased from 25 C to 45 C, the total heat generation was decreased because of the reduction of the Joule heat. Meanwhile, battery charging and discharging rate (C-rates) has significant impact on heat generation.…”

Novel investigation strategy for mini‐channel liquid‐cooled battery thermal management system

“…Various countries are paying more attention to energy security and environmental protection because of the increasingly severe energy situation and environmental pressure worldwide. New energy vehicles are beginning to emerge in the industry because of their energy cleanliness and pollutant‐free emissions . The lithium‐ion battery, the direct power source for new energy vehicles, is the core and most critical link .…”

“…New energy vehicles are beginning to emerge in the industry because of their energy cleanliness and pollutant-free emissions. [1][2][3] The lithiumion battery, the direct power source for new energy vehicles, is the core and most critical link. 4,5 The performance of the battery directly determines the development route of new energy vehicles.…”