Effect of thermal contact resistances on fast charging of large format lithium ion batteries

Ye, Yonghuang; Saw, Lip Huat; Shi, Yixiang; Somasundaram, Karthik; Tay, A.A.O.

doi:10.1016/j.electacta.2014.04.134

Cited by 107 publications

(62 citation statements)

References 45 publications

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“…For this reason, the beginning of the 1C charge stage, see Figure 3b, is crucial to reduce the cell overheating. The heat generation of discharge at 4C interpolates well between the values of reference [16] for discharges at 3C and 6C for the same cell. The correlation between the total heat generation, the heat exchange with the environment and temperature variations can be seen in Figure 4a for the 4C discharge and in Figure 4b for the 4C-1C-CV fast charge.…”

Section: Resultssupporting

confidence: 62%

“…The thickness, L i , of cell materials has been obtained by dismantling the cell and measuring them. Densities (ρ i ) and specific heats (C P,i ) have been taken from reference [16]. The cell mass was w cell = 0.075 kg.…”

Section: Resultsmentioning

confidence: 99%

“…Despite using a similar approach as the one presented here, other models [16] present more complex, higher-order differential equations which could be more difficult to implement in commercial battery management systems (BMS).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Thermal Analysis of a Fast Charging Technique for a High Power Lithium-Ion Cell

et al. 2016

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Abstract:The cell case temperature versus time profiles of a multistage fast charging technique (4C-1C-constant voltage (CV))/fast discharge (4C) in a 2.3 Ah cylindrical lithium-ion cell are analyzed using a thermal model. Heat generation is dominated by the irreversible component associated with cell overpotential, although evidence of the reversible component is also observed, associated with the heat related to entropy from the electrode reactions. The final charging stages (i.e., 1C-CV) significantly reduce heat generation and cell temperature during charge, resulting in a thermally safe charging protocol. Cell heat capacity was determined from cell-specific heats and the cell materials' thickness. The model adjustment of the experimental data during the 2 min resting period between discharge and charge allowed us to calculate both the time constant of the relaxation process and the cell thermal resistance. The obtained values of these thermal parameters used in the proposed model are almost equal to those found in the literature for the same cell model, which suggests that the proposed model is suitable for its implementation in thermal management systems.

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Section: Resultssupporting

confidence: 62%

Section: Resultsmentioning

confidence: 99%

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Thermal Analysis of a Fast Charging Technique for a High Power Lithium-Ion Cell

et al. 2016

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“…Consequently, this measurement setup allows for analyzing effects of large format electrodes without superimposing thermal gradients, as they would usually occur in a measurement setup based on commercial cells. 10,21 The cell is exposed to discharge rates of 0.1C, 0.5C, 1C and 2C at temperatures of 5…”

Section: Methodsmentioning

confidence: 99%

Simulation and Measurement of the Current Density Distribution in Lithium-Ion Batteries by a Multi-Tab Cell Approach

Erhard

Oßwald

Keil

et al. 2017

J. Electrochem. Soc.

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A single-layered NMC/graphite pouch cell is investigated by means of differential local potential measurements during various operation scenarios. 44 tabs in total allow for a highly resolved potential measurement along the electrodes whilst the single layer configuration guarantees the absence of superimposed thermal gradients. By applying a multi-dimensional model framework to this cell, the current density and SOC distribution are analyzed quantitatively. The study is performed for four C-rates (0.1C, 0.5C, 1C, 2C) at three temperatures (5 • C, 25 • C, 40 • C). The maximum potential drop as well the corresponding SOC deviation are characterized.The results indicate that cell inhomogeneity is positively coupled to temperature, i.e. the lower the temperature, the more uniform the electrodes will be utilized. Within the past decades, demand for lithium-ion batteries in mobile applications has significantly increased. Due to their well proven performance as well as their stability in long-term usage, lithium-ion batteries became the technology of choice for electrochemical energy storage devices.1,2 Still, the specific energy density as well as cycle life are constantly being optimized by either commercializing new active materials, electrolytes and additives or by reducing the fraction of non-active parts within a battery. Often, this corresponds to thicker electrodes or larger form factors leading to capacities of up to 100 Ah per cell. In these large format cells, severe gradients in current density and temperature distribution can occur along the electrode stack, 3-9 which might provoke a performance loss during operation due to inhomogeneous utilization. Also non-properly adapted thermal conditioning can have a crucial impact on the performance of larger cells. [10][11][12] Modeling of internal distributions of potential and temperature along the electrodes is quite challenging, since even to calculate only a few cycles, a lot of computational resources are required for fully resolved models. In literature, there are many examples for spatially resolved multi-dimensional modeling approaches, 8,9,[13][14][15][16] which aim at representing the cell's internal behavior in terms of potential, current density, state of charge (SOC) and temperature distribution. Unfortunately, all of these examples lack a detailed, i.e. spatially resolved experimental validation, which is capable of tracking internal variables instead of measuring the surface temperature at a few spots and considering the overall battery's terminal voltage. Also, only a few examples of direct measurements of the internal current density distribution were published so far. Zhang et al.6,7 built a specific LFP/graphite prototype cell for this purpose. A segmented cathode was used for analyzing the current distribution during discharge at varying C-rates and temperatures. This setup allows for a precise monitoring of the current of each electrode element individually. Large deviations in SOC of up to several percent were identified during the process...

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“…The large scale interest in LFP as the positive electrode has resulted in various studies on the thermal behavior of these batteries [30e32]. Electrochemicalethermal models for LFP based cells are developed to study the effect of contact resistances and heat sources [33,34], and for assessing safety limits [5]. 3D models [35,36] and cycle life models to study the capacity fade mechanisms [37e39] are also developed.…”

Section: Introductionmentioning

confidence: 99%