State Estimation Approach of Lithium-Ion Batteries by Simplified Ultrasonic Time-of-Flight Measurement

Abstract

This work presents an approach to monitoring the State-Of-Charge of Lithium-Ion battery cells via piezo disc-based ultrasonic Time-Of-Flight measurement by measuring the traveling time of a mechanical pulse through the cell between two surface-mounted sensors. The main advantage of this approach is the simplicity and the resulting low cost, which makes it suitable for future application in battery management systems. In detail, the excitation of the piezo actuator is done using a single semiconductor switch instead of a power amplifier, and the received signal is processed with an amplifier and Schmitt-trigger combination to condition the signal for the microprocessor, which is part of a battery management system. Both the functionality and the limits of the design are evaluated with a high energy density Lithium-Ion pouch cell under different operational scenarios. Several parameters such as temperature, current rates, and excitation frequency are varied to prove the design concept. For validation purposes, an estimation function is generated and a real-world driving cycle applied. An estimation with an error of 1.29 % of the Time-Of-Flight total value or 16.85 % of the State-Of-Charge value under challenging conditions is achieved with the current setup.INDEX TERMS Battery management system, diagnostics, lithium-ion battery, piezoelectric transducers, state-of-charge, time-of-flight, ultrasonic.

Measurements and modelling of the response of an ultrasonic pulse to a lithium-ion battery as a precursor for state of charge estimation

“…Ultrasonic battery monitoring is a well-established method of obtaining feature rich data from a battery. Each battery, regardless of chemistry or design, undergoes redistribution of density as a function of charge along with bulk moduli changes in anode and cathode layers [6], [7] . Many studies now exist that use ultrasound to exploit this, as well as the monitoring of battery ageing [8] , gassing [9] and swelling [10] .…”

Estimation of NCM111 /graphite acoustic properties under different lithium stoichiometry based on nondestructive acoustic in situ testing

“…For obtaining ultrasonic signal readings, in many studies, a probe was fixed to the surface of the battery with glue or a clamp. 17,23,25,26,33,36 Although it is easy to carry out, but the influences of external stresses cannot be avoided. In addition, sound wave needs a medium to propagate if probe does not touch the surface of battery.…”

“…22 The state differences of internal materials can be analyzed on the basis of the signal transmission changes in acoustic waves within a battery as ultrasonic detection is highly sensitive to material properties. 1 Gold et al, 23 Hsieh et al, 24 Popp et al, 25 Kim et al, 26 Ladpli et al, 17,27 Wu et al, 28 Zhao et al, 29 Copley et al, 30 Song et al 31 and Bommier et al 32 found that the time of flight (TOF) results of ultrasonic signal had linear relationships with the state of charge (SOC) and state of health (SOH) during charging and discharging of the battery. Moreover, Bhadra et al 22 tracked ultrasonic transmission signal with respect to the discharge process under different current rate and identified a direct correlation between changes in the acoustic waves and the physical transitions of active materials.…”

Analysis of current density in the electrode and electrolyte of lithium‐ion cells for ageing estimation applications

“…Among all the energy storage technologies, lithium-ion batteries (LIBs) are the most commonly used ones because of their inexpensive manufacturing costs and easier maintenance in smaller size. LIBs, comparing to the other technologies, have longer life cycles, higher rate of charge/discharge, and high energy density, resulting in large capacity suitable for industrial use cases [7,8]. In contrast to their many advantages, LIBs require a reliable condition monitoring system to monitor their state of health (SoH) and state of charge (SoC) due to the safety and operational issues associated with them.…”