A new method for detecting lithium plating by measuring the cell thickness

Bitzer, Bernhard; Gruhle, A.

doi:10.1016/j.jpowsour.2014.03.142

Cited by 203 publications

(146 citation statements)

References 15 publications

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“…• C. This can be explained with chemical intercalation of Li metal into adjacent graphite particles and is in agreement with experiments utilizing Li atoms evaporated onto the surface of a graphite single crystal in ultrahigh vacuum by Mandeltort et al, 52 with neutron diffraction experiments with 18650-type Li-ion cells, 41,53 with operando measurements of the thickness of pouch cells 54,55 from other groups, and with ARC experiments with the same type of 18650 cells is in the present paper after different rest times from our group.…”

Section: Post-mortem Analysis Reveals Different Aging Mechanisms In 325supporting

confidence: 86%

Electrochemical, Post-Mortem, and ARC Analysis of Li-Ion Cell Safety in Second-Life Applications

Waldmann

Quinn

Richter

et al. 2017

J. Electrochem. Soc.

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Li-ion cells are used in a variety of mobile and stationary applications. Their use must be safe under all conditions, even for aged cells in second-life applications. In the present study, different aging mechanisms are taken into account for accelerating rate calorimetry (ARC) tests. 18650-type cells are cycled at 0 • C (Li plating expected) and at 45 • C (SEI growth expected). After extensive evaluation of the electrochemical results (voltage curve analysis, capacity fade, energy fade, Coulombic efficiency), the cells are tested by PostMortem analysis (CT, GD-OES, SEM) to reveal the main aging mechanisms and by ARC to test the safety behavior. Besides typical ARC results such as onset-of-self-heating, onset-of-thermal runaway and maximum temperatures, as well as acoustic responses of thermal runaway are evaluated and a method is developed to compare fresh cells and cells aged until different SOHs. It turns out that the safety of aged cells is not simply a function of the SOH. However, safety is strongly affected by the main aging mechanism and to the history of operating parameters during the life-time of the cell. Driven by the demand for higher capacity, lower volume, and lower weight, Li-ion technology was developed in the 1980s.1,2 Nowadays, Li-ion technology is used for energy storage in a large variety of applications, e.g. smartphones, tablets, or drones. In particular, electric vehicles in combination with renewable energy sources are promising for reducing climate change and the corresponding glacier melting and sea level rise which is influenced by burning fossil fuels.3-6 For all applications, the safety behavior under all specified operating conditions is most important.7-9 The same is true for aged Li-ion cells used in second-life applications, for example cells which are utilized in stationary energy storage applications after their usage in electric cars.In the past, failure of Li-ion cells led to product recalls which are very expensive for the manufacturers and unsettle customers, even if such incidents happen only in very few cases (ppm range).10 At the moment, safety tests have to be performed with Li-ion prototypes cells before market release. In these tests, fresh cells are always used, however, aged cells are usually neglected. Even if fresh cells show an acceptable safety behavior, this can change for aged cells. 7,[11][12][13][14][15] While some authors observed decreases for certain safety properties, 7,11,12 others found improvements. 12,13,15 It is well known that aging mechanisms change the properties of the materials inside Li-ion cells. [16][17][18][19] Operating conditions and materials have a strong influence on these aging mechanisms. 12,[20][21][22][23] We recently reported on a change of the aging mechanism with temperature for cycling aging of commercial 18650-type cells with graphite anodes and NMC/LMO cathodes. 20 This mechanism change is expressed by a V-shape in Arrhenius plots of the capacity fade rates obtained from cycling at different ambient temperatures. 20 This c...

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Section: Post-mortem Analysis Reveals Different Aging Mechanisms In 325supporting

confidence: 86%

Electrochemical, Post-Mortem, and ARC Analysis of Li-Ion Cell Safety in Second-Life Applications

Waldmann

Quinn

Richter

et al. 2017

J. Electrochem. Soc.

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“…This localized lithium deposition is likely to result in increased localized stress, as it has previously been observed that lithium deposition can cause measurable changes in cell thickness. 39,40 This local increase in stress could lead to further separator deformation, creating a potential positive feedback scenario in which defects grow. Similarly, if the lithium deposit becomes electronically disconnected from the underlying graphite (as is often observed experimentally, 3,4,5,1,38 ) the dead lithium deposit itself becomes a defect, restricting transport in the same manner as separator pore closure.…”

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confidence: 99%

The Effects of Defects on Localized Plating in Lithium-Ion Batteries

Cannarella

Arnold

2015

J. Electrochem. Soc.

174

132

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This work investigates how local cell defects can induce local lithium deposition and dendrite growth in a lithium-ion cell that appears to otherwise be performing correctly. Using local pore closure in the battery separator as a model defect, we experimentally demonstrate the occurrence of local lithium deposition during cycling in coin cells containing deliberately manufactured local regions of separator pore closure. We further investigate the local plating phenomena observed in these experiments using an axisymmetric finite element model of the defect-containing coin cell geometry. Our simulations show that the pore closure acts as an "electrochemical concentrator," creating locally high currents and overpotentials in the adjacent electrodes. This leads to lithium plating if the local overpotential exceeds equilibrium potential in the negative electrode. We examine the sensitivity of the local plating behavior to various materials, geometric, and operating parameters to identify mitigation strategies. The results of this work can be generalized to any defect that creates spatially non-uniform current distributions. The formation of metallic lithium, or lithium plating, is a wellknown and potentially dangerous degradation mechanism in lithiumion batteries.1 Lithium plating directly leads to capacity loss through corrosion with the cell's electrolyte 2 and in the worst case scenarios can lead to catastrophic failure by creating an internal short circuit. 1 Recent work shows a link between mechanics and lithium plating such that lithium plating is aggravated at higher levels of internal mechanical stress 3 and generally occurs in a periodic structure indicative of the cell's mechanical design. 3,4,5 However, the underlying physical mechanisms governing the relationship between lithium plating and mechanical stress remain unexplained. In this work we explain the observed link by experimentally demonstrating that local mechanical deformation of the battery separator can cause local lithium plating in an otherwise well-functioning cell. We support these experimental results with numerical simulations and an analytical analysis, which show that local separator deformation creates "hot spots" of locally high electrochemical activity that can cause local plating. While this work uses separator deformation as a model mechanical defect, the results are generally applicable to any defect that results in non-uniform ionic currents. Our results demonstrate the essential role of nonuniformities in causing failure in a seemingly well-functioning and welldesigned battery cell, suggesting a new paradigm in which batteries are designed to be resistant to failure in the presence of an assumed pre-existing defect.There are many known lithium-ion cell defects in addition to separator deformation that can result in spatially non-uniform internal operation.6 Some examples of defects in lithium-ion cells include local electrolyte drying, 7 current collector delamination, 7 electrode/separator interface separation, 8 copper plating f...

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“…[3][4][5] In contrast, Li deposition and subsequent reaction with electrolyte is usually observed after charging at low temperatures and/or high rates. 4,[6][7][8][9][10][11] Li deposition causes rapid capacity decay 4,11 and can significantly reduce cell safety. 12 The reason for lithium deposition is anode polarization, which drops below 0 V vs. Li/Li + in the respective cases.…”

mentioning

confidence: 99%

“…Therefore, non-destructive methods for detection of Li deposition and quantification are under development by several groups. [7][8][9][10] In order to validate non-destructive detection methods, one has to be able to detect Li chemically after cell opening. Petzl et al recently used the reactivity of Li with water as a sign of metallic Li on graphite anodes.…”

mentioning

confidence: 99%

Detection of Li Deposition by Glow Discharge Optical Emission Spectroscopy in Post-Mortem Analysis

Ghanbari

Waldmann

Kasper

et al. 2015

ECS Electrochemistry Letters

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Glow discharge optical emission spectroscopy (GD-OES) is employed to detect and quantify Li deposition as a function of depth on graphite electrodes. Commercial cells with graphite anodes were subject to Li plating by being cycled at 5 Li-ion batteries suffer from aging reactions which limit their lifetime in applications.1,2 It is known that chemical reactions such as SEI growth on anodes and dissolution of cathode active material are accelerated with increasing temperature, following an Arrhenius-like behavior. [3][4][5] In contrast, Li deposition and subsequent reaction with electrolyte is usually observed after charging at low temperatures and/or high rates. 4,[6][7][8][9][10][11] Li deposition causes rapid capacity decay 4,11 and can significantly reduce cell safety. 12The reason for lithium deposition is anode polarization, which drops below 0 V vs. Li/Li + in the respective cases. 4,6 However, measuring the anode potential in full cells requires a reference electrode that is not present in commercial cells. Therefore, non-destructive methods for detection of Li deposition and quantification are under development by several groups. 7-10In order to validate non-destructive detection methods, one has to be able to detect Li chemically after cell opening. Petzl et al. recently used the reactivity of Li with water as a sign of metallic Li on graphite anodes. 7 In post-mortem analysis, the high reactivity of Li metal makes it challenging to open the cell in charged state, especially in the presence of deposited Li. Analysis of graphite anodes subject to Li deposition can be done using methods such as inductively coupled plasma spectroscopy (ICP) and atomic absorption spectroscopy (AAS), however, distinguishing between metallic Li and intercalated Li is not possible. Therefore, a quantification of Li deposition in postmortem analysis is not available in literature at the moment.Glow Discharge Optical Emission Spectroscopy (GD-OES) was introduced by Grimm in 1968 13 and later used as a standard method for characterization of non-porous metallic materials, e.g. in steel industry. Similar to X-ray photoelectron spectroscopy (XPS) depth profiling, GD-OES employs an inert gas (usually Ar) as discharge source to perform a depth-resolved elemental analysis sensitive to light elements like Li. XPS is, however, a surface-sensitive method while GD-OES can be applied through the whole electrode coating.Recently, GD-OES has been also applied to porous electrodes from Li-ion batteries by Saito et al.14 The technique was further developed by Takahara et al., focusing on reactive sputtering, Li quantification in the electrodes and analysis of surface deposition on graphite anode (SEI). 15-18The present study introduces a novel method to prove Li deposition on graphite anodes of Li-ion batteries by means of GD-OES depth profiling. For comparison, anodes from cells where Li plating is expected (cycling at low temperatures) are compared to anodes without Li plating but initial SEI formation (anodes from fresh cell). ExperimentalG...

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A new method for detecting lithium plating by measuring the cell thickness

Cited by 203 publications

References 15 publications

Electrochemical, Post-Mortem, and ARC Analysis of Li-Ion Cell Safety in Second-Life Applications

Electrochemical, Post-Mortem, and ARC Analysis of Li-Ion Cell Safety in Second-Life Applications

The Effects of Defects on Localized Plating in Lithium-Ion Batteries

Detection of Li Deposition by Glow Discharge Optical Emission Spectroscopy in Post-Mortem Analysis

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