In Situ Measurement of Orthotropic Thermal Conductivity on Commercial Pouch Lithium-Ion Batteries with Thermoelectric Device

Abstract

In this paper, the direct measurement of the orthotropic thermal conductivity on a commercial Li-ion pouch battery is presented. The samples under analysis are state-of-the art batteries obtained from a fully electric vehicle commercialized in 2016. The proposed methodology does not require a laboratory equipped to manage hazardous chemical substances as the battery does not need to be disassembled. The principle of the measurement methodology consists of forcing a thermal gradient on the battery along the desired direction and measuring the heat flux and temperature after the steady state condition has been reached. A thermoelectric device has been built in order to force the thermal gradient and keep it stable over a long period of time in order to be able to observe the temperatures in steady state condition. Aligned with other measurement methodologies, the results revealed that the thermal conductivity in the thickness direction (0.77 Wm−1K−1) is lower with respect to the other two directions (25.55 Wm−1K−1 and 25.74 Wm−1K−1) to about a factor ×35.

Open-source tool for battery module simulation and design

“…= (10) To increase the accuracy of the m odel, the param eters of the cells have been assum ed to vary with cell tem perature and SOC ; this has been im plem ented using look-up tables. The SOC of each cell can be estim ated using (11), while the tem perature corresponds to the one calculated by the therm al subsystem in the core of the respective cell. In (11), the subindex i is the corresponding tim e step, t the tim e and C ap the refence capacity of the cell.…”

“…The SOC of each cell can be estim ated using (11), while the tem perature corresponds to the one calculated by the therm al subsystem in the core of the respective cell. In (11), the subindex i is the corresponding tim e step, t the tim e and C ap the refence capacity of the cell. Equation 10 m akes the system of equations of the electric subsystem not linear, thus in the tool algorithm an iterative procedure based on the bisection m ethod was im plem ented to solve the system ; the current of the m odule is the iteration variable.…”

“…The purpose of the foam layers is to com pensate cell deform ations and to m aintain the m ounting pressure on the cells during the working cycles; the alum inum layers, instead, aid therm al conduction. The num ber of nodes has been defined to get a sufficiently good accuracy of the results with lim ited com putational tim e. The therm o-physical properties of the cell were taken from [11], where they were identified for a cell with a sim ilar chem istry (N M C ). The com pensation pad properties were taken from [12] and the fram e m aterial was assum ed to be polypropylene as suggested for battery containers in [13].…”

Thermal Conductivity in Aged Li-Ion Cells under Various Compression Conditions and State-of-Charge

“…For the determination of the through-plane thermal conductivity, a temperature gradient was forced across the thickness direction of the cell using a temperature guarded plate and a heater until a steady state condition was reached [27]. Temperature values were measured on the top (hot side) and bottom (cold side) of the cell via K-type thermocouples.…”

A Novel Cathode Material Synthesis and Thermal Characterization of (1-x-y) LiCo1/3Ti1/3Fe1/3PO4, xLi2MnPO4, yLiFePO4 Composites for Lithium-Ion Batteries (LIBs)

“…By using this model, the physicochemical property values were temperature dependent based on the Arrhenius equation, which defines the temperature sensitivity of a general physiochemical property, Ψ, as follows: where is the property value defined at reference temperature and = 25 °C. Here, the controls the temperature sensitivity [ 41 , 42 , 43 ]. In viewpoint of temperature dependence, we define operating maps of discharge and charge power capability as a function of temperature initial condition and cell temperature.…”