Instrumentation & Measurement Magazine 24-3 - 94

which helps the evaluation of balancing function and provides The solution must then be corrected for temperature changes
information concerning system availability. The results of the and the required current. Given that batteries are voltage
experiment in [31] show that IoT technology improves the sources, which by definition, are meant to maintain a constant
remote-based control and monitoring of the system consider- voltage, ΔV measured by the system using a voltage method
ably. IoT technology provides a practical solution to overcome becomes increasingly difficult, particularly for the new generthe battery charging and discharging related issues in EVs.
ation of batteries.
IoT cloud-based monitoring is also proposed to support
Advanced techniques for SoC calculations involve using
the BESS network topology. Cloud-based monitoring can be statistical filters, such as the Kalman filter, which incorporates
utilized for devices in an expandable wireless network. New the Coulomb Counting method with the voltage method to
nodes can be accommodated without interrupting the flow overcome the shortcomings of either of the two methods. With
of information. All systems under the aforementioned design cloud-based battery monitoring and management, a larger daare connected wirelessly, eliminating physical vulnerabilities tabase can be formed by cloud-based BMS or MMS networks.
while also adding a level of noise immunity for larger systems. It is shown in [4] that commercially available cloud database
Cloud-based monitoring also offers more storage and data services, such as Firebase/Google, and machine learning tools,
analysis tools to detect defects and outliers within the vehicle such as Google OR-Tools, can be used to further enhance SoC
battery pack. Certain software tools can flag abnormalities that estimation in cloud-enabled BESS networks. Such tools offer
may be related to the faulty condition of certain vehicle parts. correction for battery performance and battery physical and
For instance, if a mechanical problem causes a battery mod- chemical characteristics. It is apparent that with more data
ule to fail earlier than the rest, this defect can be detected using storage capacity and access to high-performance cloud comcloud-based monitoring software. The EV manufacturers can puting, this method offers better SoC estimation. In [4], it is
also be notified if any production defects exist within a par- also reported that Lithium-ion batteries require a specially deticular model or if the overall design has a performance flaw. signed system to ensure maximum efficiency, reliability, and
Manufacturers can use machine learning tools to diagnose and system safety. BMS usually supports module communicacorrect problems as they occur, allowing the industry to take tion through wired systems. However, using wired networks
a proactive approach to design and improvement. Various adds to the complexity of certain issues, such as difficulty
simulation models including electrical circuit, thermal, elec- in manufacturing, increased wiring costs, and complex detro-mechanical, and BMS models can be applied to improve sign procedures for battery packets due to isolation concerns.
the performance of the traditional BESS design architecture.
To minimize the wiring complexity in BMSs, research studAlong with fault diagnosis and passenger safety, opera- ies on Wireless Battery Management Systems (WBMSs) have
tional states, such as SoC calculations, can also be improved. been carried out. The WBMS not only minimizes the wiring
SoC is often calculated using a variety of methods. The complexity but also supports location positioning for battery
chemical method involves measuring the pH of the battery modules [34]. Linear Technologies Corporation has introelectrolyte. Measuring a battery's internal pressure is also duced a WBMS with an embedded smart mesh, in which
proven to be useful in calculating SoC for Nickel Metal Hydride different nodes are wirelessly connected to their neighborbatteries. However, this method requires access to the battery's ing nodes. The main node in this system may be overloaded
electrolyte. The current integration method, known
as the Coulomb Counting
method, involves integrating the measured device
current drawn over time,
yielding coulombs consumed. This requires the
device to have an accurate reference point for
the number of coulombs
in a fully charged battery.
This method is also more
susceptible to errors in
measurement that cause
long-term drift and inaccurate SoC calculations. The
voltage method plots the
battery pack closed-circuit
voltage and compares the
Fig. 4. The schematic of WBMS proposed by Linear Technologies Corporation [4].
data against known curves.
94

IEEE Instrumentation & Measurement Magazine

May 2021

Instrumentation & Measurement Magazine 24-3

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