Characterization and modeling of the thermal mechanics of lithium-ion battery cells

Abstract

h i g h l i g h t sThermal swelling shape is different than Li-ion intercalation swelling shape. Nonuniform temperature and gap creation leads to a convex shape at free conditions. Important parameters of thermal mechanics are estimated through experiments. A coupled thermal-structural analysis accurately predicts thermal swelling shape. Nonuniform temperature still plays a critical role at pack conditions. Keywords:Lithium-ion battery Battery swelling shape Thermal expansion The coefficient of thermal expansion The coupled thermal-structural analysis a b s t r a c tThe thermal mechanics of Lithium-ion (Li-ion) batteries is explored with a focus on thermal swelling. Experiments show for the first time that the swelling shape of prismatic battery cells due to temperature variations is significantly different from that due to Li-ion intercalation in unconstrained conditions. In contrast to uniform and orthotropic Li-ion intercalation swelling in a direction perpendicular to electrodes, the nonuniform temperature distribution in the jellyroll and the gaps/voids between electrodes result in distinguishable different swelling shapes. A unique coupled thermal-structural analysis with a simple, but efficient 3-D finite numerical model is proposed to investigate the impact of temperature variations on the thermal behaviors of battery cells. Anisotropic heat conduction and temperature dependency of the coefficient of thermal expansion are taken into account and found to have an impact on temperature distribution and thermal expansion. Experimental validation of the proposed model clearly demonstrates that the coupled thermal-structural analysis with the proposed model can predict accurately the thermal swelling at unconstrained conditions. The solution at pack (constrained) conditions shows that the nonuniform temperature distribution of the jellyroll still plays a critical role for the thermal swelling shape, although the gaps/voids do not occur because of the constraints from spacers in the pack, suggesting that the estimation of core temperature is important. Such an accurate model, able to estimate cell thermal behavior, is beneficial to the design of Li-ion batteries, development of stress or strain sensors, optimum sensor placement, and thermal management of not only single battery cells but also battery packs.

A review on battery management system from the modeling efforts to its multiapplication and integration

“…Bandhauer et al utilized a passive liquid‐vapor phase change heat removal inside micro‐channels embedded into the cell to demonstrate the possible performance improvement based on a 3D electrochemical‐thermal model. Figure shows the maximum temperature rise and difference for the internal cooling simulations as compared with the traditional air and liquid cooling reports in Bandhauer et al Based on the three‐dimensional thermal swelling model with coupled thermo‐mechanical, Oh and Epureanu indicated the elevated core temperature and uneven temperature distributions play a vital role in the performance of the battery pack. This model is beneficial to the design thermal management of battery packs, as well as the development of stress‐strain sensors and the optimal configuration.…”

Resistance exterior force property of lithium‐ion pouch batteries with different positive materials

“…The positive electrode and negative electrode are coated on aluminum foil and copper foil, respectively, and entire LIPB structure is wrapped by aluminum plastic soft casing. The main problem of LIPB in engineering application is that a moving battery sustains a variety of quasi‐static or dynamic loadings and these loadings could easily cause serious consequence, such as capacity and property degradation, ISC, fire, and even severe explosion . The resistance exterior force property of LIPB represents the ability to resist the exterior loading (quasi‐static or dynamic loadings).…”

“…The main problem of LIPB in engineering application is that a moving battery sustains a variety of quasi-static or dynamic loadings and these loadings could easily cause serious consequence, such as capacity and property degradation, 8,9 ISC, fire, and even severe explosion. 2,[10][11][12][13][14] The resistance exterior force property of LIPB represents the ability to resist the exterior loading (quasi-static or dynamic loadings). And it is an important indicator for design specification and battery analysis and it directly reflects the safety and reliability of battery.…”

In Situ Stress Measurement Techniques on Li-ion Battery Electrodes: A Review

“…MuKai et al [60] validated that lithium manganese oxide spinels had average coefficients of volumetric thermal expansion by the maximum value of 2.39 × 10 −5 K −1 with X-ray diffraction measurements performed in the temperature range from 100 to 400 K. Because of thermal expansion of cathode, anode, and separator in a cell, Oh and Epureanu [61] found a 5Ah NMC cathode Li-ion cell swelling linearly in the through plane from 25 to 45 • C. Stress generation of a NMC cathode battery stack caused by temperature has been measured by Mohan et al [62], who found the bulky force at the battery stack surface increase with temperature rising from −5 to 45 • C at the same SOC level.…”

“…Although the availability of published data from in situ electrode stress/strain measurements is limited, factors that influence electrode stress generation also include the effects due to thermal expansion/contraction [60][61][62] and gas generation originated from electrochemical decomposition of electrolyte solvents by the SEI layer formation, high temperature operation, and overcharge [63][64][65]. The winding process of electrodes is the important production technique for Li-ion battery fabrication [66], which can also cause electrode stress generation from external forces and body forces.…”