The effect of thermal gradients on the performance of lithium-ion batteries

Troxler, Yannic; Wu, Billy; Marinescu, Monica; Yufit, Vladimir; Patel, Yatish; Marquis, A. J.; Brandon, Nigel P.; Offer, Gregory J.

doi:10.1016/j.jpowsour.2013.06.084

Cited by 190 publications

(146 citation statements)

References 47 publications

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“…It has been shown that a battery under a temperature gradient behaves differently than a battery at the same average isothermal temperature 32 because of non-uniform impedance. Additionally, there has been some work exploring the effects of temperature gradients on degradation that show that a temperature gradient increases the rate of degradation of lithium-ion batteries.…”

Section: 24mentioning

confidence: 99%

Surface Cooling Causes Accelerated Degradation Compared to Tab Cooling for Lithium-Ion Pouch Cells

Hunt

Zhao

Patel

et al. 2016

J. Electrochem. Soc.

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160

119

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One of the biggest causes of degradation in lithium-ion batteries is elevated temperature. In this study we explored the effects of cell surface cooling and cell tab cooling, reproducing two typical cooling systems that are used in real-world battery packs. For new cells using slow-rate standardized testing, very little difference in capacity was seen. However, at higher rates, discharging the cell in just 10 minutes, surface cooling led to a loss of useable capacity of 9.2% compared to 1.2% for cell tab cooling. After cycling the cells for 1,000 times, surface cooling resulted in a rate of loss of useable capacity under load three times higher than cell tab cooling. We show that this is due to thermal gradients being perpendicular to the layers for surface cooling leading to higher local currents and faster degradation, but in-plane with the layers for tab cooling leading to more homogenous behavior. Understanding how thermal management systems interact with the operation of batteries is therefore critical in extending their performance. For automotive applications where 80% capacity is considered end-of-life, using tab cooling rather than surface cooling would therefore be equivalent to extending the lifetime of a pack by 3 times, or reducing the lifetime cost by 66%. Due to their high energy and power densities, Lithium-ion batteries are a very important component of electric vehicles, and their use has increased dramatically in recent years as the uptake of hybrid and electric vehicles has increased.1-3 One of the major challenges of using lithium-ion batteries in hybrid and electric vehicles is thermal management, 4 which is important in order to manage degradation at an acceptable rate whilst maximizing the performance of the batteries and reducing the risk of thermal runaway. 5-7Many studies have shown that increased temperature leads to an increase in the rate of degradation, 4,[8][9][10][11] therefore the effectiveness of a thermal management system is vital in order to maximize the lifetime performance of the pack. The design of a good thermal management system for a battery pack should consider both the overall temperature of the pack and both intra-cell and internal thermal gradients. Poor design of thermal management systems could be a major contributing factor in increasing degradation rates to unacceptable levels. 12There are many different techniques that can be used to thermally manage batteries in hybrid and electric vehicles. It is possible to use either air or liquid as the cooling medium, and both of these can be used in either a direct (with cooling medium in contact with the cell) or indirect way. In addition to this, different areas of the cell can be cooled, namely the surfaces of the cell or the cell tabs. 13,14 In general, systems employing air as the cooling medium are considered to be simpler and cheaper to implement, although the performance is limited especially in applications where there is a high heat generation rate or if the batteries are being operated in a high ambient tempe...

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Section: 24mentioning

confidence: 99%

Surface Cooling Causes Accelerated Degradation Compared to Tab Cooling for Lithium-Ion Pouch Cells

Hunt

Zhao

Patel

et al. 2016

J. Electrochem. Soc.

Self Cite

160

119

View full text Add to dashboard Cite

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“…Furthermore, temperature gradients within cells through the central plane have been reported to also contribute to accelerated degradation [38,39]. Parts of the cell at elevated temperatures are expected to have a lower resistance, allowing more current to flow through it, in turn heating up more via a positive feedback process between unique layers that are electrically connected in parallel, and localised parts in the same layer.…”

Section: Hp Cycle Validationmentioning

confidence: 99%

Duty-cycle characterisation of large-format automotive lithium ion pouch cells for high performance vehicle applications

Kellner

Worwood

Barai

et al. 2018

Journal of Energy Storage

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A B S T R A C TThe long-term behaviour of lithium ion batteries in high-performance (HP) electric vehicle (EV) applications is not well understood due to a lack of suitable testing cycles and experimental data. As such a generic HP duty cycle (HP-C), representing driving on a race track is validated, and six NMC graphite cells are characterised with respect to cycle-life. To enable a comparison between the HP-EV environment and conventional road driving, two test groups of cells are subject to an experimental evaluation over 200 duty cycles that includes a representative HP-C and a standard duty cycle from the IEC 62660-1 standard (IECC). After testing, both test groups display increased energy capacity, increased pure Ohmic resistance, lower charge transfer resistance an extended OCV operating window. The changes are more pronounced for cells subject to the HP-C. Based on capacity tests, Electrochemical Impedance Spectroscopy (EIS), pseudo-OCV tests, and Pulse Multisine Characterisation, it is concluded that the changes in cell characteristics are most likely caused by cracking of the electrode material caused by high electrical current pulses. With continued cycling, cells cycled with the HP-C are expected to show degradation at an increased rate due to raised temperatures, and more pronounced electrode cracking.

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“…Thus, the hotter cells decay faster, which shortens the lifespan of the module/pack [8]. Also, overheating and non-uniform temperature gradient without sufficient dissipation will deteriorate SOC and SOH of cells, which triggers the thermal runaway, premature failure of cells [9,10]. Additionally, at low temperatures, a common phenomenon to Li-ion cells is that the capability and ageing will begin to deteriorate quickly as the temperature falls below − 10 °C [11].…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation on Cooling/Heating Characteristics of Ultra-Thin Micro Heat Pipe for Electric Vehicle Battery Thermal Management

Liu

Lan

Chen

et al. 2018

Chin. J. Mech. Eng.

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Due to the heat pipes' transient conduction, phase change and fluid dynamics during cooling/heating with high frequency charging/discharging of batteries, it is crucial to investigate in depth the experimental dynamic thermal characteristics in such complex heat transfer processes for more accurate thermal analysis and design of a BTMS. In this paper, the use of ultra-thin micro heat pipe (UMHP) for thermal management of a lithium-ion battery pack in EVs is explored by experiments to reveal the cooling/heating characteristics of the UMHP pack. The cooling performance is evaluated under different constant discharging and transient heat inputs conditions. And the heating efficiency is assessed under several sub-zero temperatures through heating films with/without UMHPs. Results show that the proposed UMHP BTMS with forced convection can keep the maximum temperature of the pack below 40 °C under 1 ~ 3C discharging, and effectively reduced the instant temperature increases and minimize the temperature fluctuation of the pack during transient federal urban driving schedule (FUDS) road conditions. Experimental data also indicate that heating films stuck on the fins of UMHPs brought about adequate high heating efficiency comparing with that stuck on the surface of cells under the same heating power, but has more convenient maintenance and less cost for the BTMS. The experimental dynamic temperature characteristics of UMHP which is found to be a high-efficient and lowenergy consumption cooling/heating method for BTMSs, can be performed to guide thermal analysis and optimization of heat pipe BTMSs.Keywords: Electric vehicle, Lithium-ion battery, Thermal management, Ultra-thin micro heat pipe © The Author(s) 2018. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creat iveco mmons .org/licen ses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

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The effect of thermal gradients on the performance of lithium-ion batteries

Cited by 190 publications

References 47 publications

Surface Cooling Causes Accelerated Degradation Compared to Tab Cooling for Lithium-Ion Pouch Cells

Surface Cooling Causes Accelerated Degradation Compared to Tab Cooling for Lithium-Ion Pouch Cells

Duty-cycle characterisation of large-format automotive lithium ion pouch cells for high performance vehicle applications

Experimental Investigation on Cooling/Heating Characteristics of Ultra-Thin Micro Heat Pipe for Electric Vehicle Battery Thermal Management

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