Impedance Based Temperature Estimation of Lithium Ion Cells Using Artificial Neural Networks

Abstract

Tracking the cell temperature is critical for battery safety and cell durability. It is not feasible to equip every cell with a temperature sensor in large battery systems such as those in electric vehicles. Apart from this, temperature sensors are usually mounted on the cell surface and do not detect the core temperature, which can mean detecting an offset due to the temperature gradient. Many sensorless methods require great computational effort for solving partial differential equations or require error-prone parameterization. This paper presents a sensorless temperature estimation method for lithium ion cells using data from electrochemical impedance spectroscopy in combination with artificial neural networks (ANNs). By training an ANN with data of 28 cells and estimating the cell temperatures of eight more cells of the same cell type, the neural network (a simple feed forward ANN with only one hidden layer) was able to achieve an estimation accuracy of ΔT= 1 K (10 ∘C <T< 60 ∘C) with low computational effort. The temperature estimations were investigated for different cell types at various states of charge (SoCs) with different superimposed direct currents. Our method is easy to use and can be completely automated, since there is no significant offset in monitoring temperature. In addition, the prospect of using the above mentioned approach to estimate additional battery states such as SoC and state of health (SoH) is discussed.

A Generic Approach to Simulating Temperature Distributions within Commercial Lithium-Ion Battery Systems

“…To what extent reducing the number of sensors used during the experiments affects the quality of the resulting model parameterization is to be tested in further investigations. Also, promising and completely noninvasive methods such as impedance-based temperature determination, as introduced, among others, in [53,54], must be assessed in order to further simplify the parameterization process.…”

Optimizing Current Collector Interfaces for Efficient “Anode‐Free” Lithium Metal Batteries

“…Regarding the first point, Cu current collectors, which are used for conventional anodes and cannot be used as reactions with sulfide electrolytes have been reported to lead to Cu corrosion and thus poor cell performance. [ 147 ] Thus, alternative CCs need to be applied. In recent studies, mainly stainless‐steel foils have been adopted as CCs for anode‐less approaches, [ 148–151 ] whereas Ni foil was used for graphite coatings.…”

High Flashpoint and Eco-Friendly Electrolyte Solvent for Lithium-Ion Batteries

“…Improving the thermal safety of lithium-ion batteries can be achieved in several ways. One option is to develop enhanced temperature determination, which records the core temperature of each cell to detect a thermal runaway at an early stage [1][2][3][4]. Other options include phase change materials for passive cooling of the cells [5] or making the cell's chemistry safer [6,7].…”