What Are Smart Battery Cells? Definition, Applications & Advantages

Phones, watches and TVs have all received the ‘smart’ upgrade. Now, batteries are enjoying the same treatment. Designed to offer superlative performance, smart battery cells set a new standard for energy storage and delivery. So, what exactly are smart battery cells? Read on to find out more about the exciting new technology and what it means for the energy sector.

Smart batteries: 101

Communication is what sets smart cells apart from regular batteries. Before we dive in, let’s take a quick look at the anatomy of a battery pack. Most batteries are made up of individual components called cells. Multiple cells are assembled to generate more power. This group is called a module. Packs are then created by assembling multiple modules.

Smart batteries use a battery management systems (BMS) to monitor each individual cell. This is a big task. For example, lithium ion battery systems used in the Tesla Model S feature around 450 individual cells.

Tracking key parameters is one of the most important roles of a BMS. This includes:

• Measuring voltage and current
• Calculating charge level
• Determining the State of Health (SoH) of each individual cell

Smart battery cells also have the capacity to communicate externally. This includes relaying information to the charger to control, monitor and optimise the charging process.

From passive components to smart mechatronic devices

At the University of Warwick in England, researchers at the Warwick Manufacturing Group (WMG) department are working hard to engineer lithium ion batteries with built-in sensing, communication and control features. The vision is to transform passive lithium ion batteries into intelligent mechatronic devices with ‘smart’ hardware built directly into each cell. This will equip batteries with the ability to:

• Regulate or isolate electrical currents as they flow through terminals
• Measure and record important variables, including cell temperature, current density, mechanical stress, electrode potentials and gas pressure
• Communicate with users and external equipment using wireless technology

“Significant advances have been made in understanding the degradation, manufacturability and recyclability of lithium ion batteries,” reads an information leaflet issued by the WMG.

Despite innovations in automotive, aerospace, energy storage and other battery applications, individual battery cells haven’t been reimagined as active components. “Energy transfer is governed by the requirements of the external load or supply, often with limited insight on the impact this will have on performance, life and safety,” write the authors. Ultimately, the goal is to reinvent batteries as smart mechatronic devices, as opposed to passive components.

Putting the ‘smart’ in smart batteries

Transforming batteries from passive to active components takes a huge amount of research and innovation. Here’s how engineers at WMG are doing it:

Advanced characterisation techniques

Integrated sensors and instruments are used to track battery performance and monitor degradation. These smart technologies offer insight not previously possible with traditional sensing technologies. Safety is front of mind, with built-in sensors used to monitor increases in internal cell temperature, as well as other ‘red light’ safety parameters like pressure. The WMG team is also using spatial variations in mechanical strain and temperature to track performance and improve the safety of larger cells.

“This research is driving new physics informed models of the battery and new approaches to state-of-X (SoX) estimation for next-generation battery management systems,” reads the WMG leaflet.

Direct manufacture

Looking to the future, the WMG team hopes to engineer smart lithium ion batteries that can be directly manufactured. Integrating smart cells into battery packs during the manufacturing process would significantly increase parameters like performance and life cycle, as well as safety and sustainability.

Technologies driving the smart battery revolution

Below, we take a closer look at some of the cutting-edge technologies driving the smart battery revolution.

Next-generation cell engineering

Advances in cell engineering are at the heart of the smart battery revolution. Integrating multiple internal sensors into battery cells allows users to unlock information on a myriad of parameters, including temperature, pressure and thermal runaway.

Optical fibre integration

Optical fibres offer users insight into spatially resolved temperature, density and mechanical strain measurements in large format batteries. The technology allows engineers to distribute sensors across the entire cell, which ensures accurate and reliable data.

The WMG leaflet explains, “Through optical fibre sensing, we have demonstrated simultaneous decoding of internal temperature and strain within a pouch cell. This has underpinned the development of new state of health (SOH) assessment based on solid electrolyte interphase (SEI) formation and anode structural deformation.”

Applications for smart battery cells

From electric vehicles to battery-powered planes, smart cells are revolutionising sectors like transport and energy storage. Here’s a closer look at what we’re seeing:

Automotive

Electric vehicles are the transport of the future. While uptake has been slow due to supply issues and infrastructure challenges, experts predict that by 2025 plug-in cars will accounts for around 23% of all new global sales of passenger vehicles. However, many consumers still have concerns. Lacklustre battery range, slow charge times and limited life cycle are some of the biggest challenges associated with EVs. Smart battery cells are being used to address these issues.

German automotive supplier Vitesco Technologies recently confirmed a BMS order worth more than £1.7 billion. The company will manufacture control units equipped with wireless communication technology, which will significantly reduce the weight and overall footprint of the battery units.

Each BMS will feature two controllers. The first contains algorithms to track the state of battery cells and take corrective action if irregularities are detected. The second controller features a Cell Supervising Circuit to monitor individual cells and balance the charge and discharge processes.

Key goals include:

• Balancing the charge level of all individual battery cells within the system
• Ensuring cells discharge evenly
• Prevent performance and safety issues like overheating
• Extend the service life of the battery system

“With our modular software and hardware for battery management we can offer our customers tailor made solutions,” says Thomas Stierle, head of Electrification Technology and Electronic Controls at Vitesco Technologies. “In addition, innovations such as wireless communication with the battery modules enable advanced battery design, leading to reduced system costs for our customers.”

Powering up heavy-duty vehicles

In the book Heavy-Duty Electric Vehicles: From Concept to Reality, the authors explain how smart battery management systems are critical when designing powerful EVs. Single lithium ion cells don’t generate enough energy to operate an electric powertrain. So, multiple cells are used to build a battery pack and increase power. While effective, intercellular variations are inevitable. External factors like variations in temperature gradient, discharge rates and alternating current resistance amplify these variations with continued use. This can have a negative impact on performance.

This is where BMS technology step up. The intelligent systems can be used to monitor performance, track irregularities and assess the health of each individual cell. Ultimately, battery management systems will help engineers design powerful and efficient heavy-duty EVs that hold their own against their combustion engine counterparts.

Industrial tech company Sensata Technologies recently launched a new BMS designed specifically for high-voltage applications. It’s called the Lithium Balance n3-BMS and meets the needs of electric trucks, buses and other heavy-duty vehicles. Thanks to a layered software structure, the BMS allows operators to customise the system with their own algorithms and codes. This allows users to optimise battery performance, without risking non-compliance with strict safety standards like ISO 26262.

Aerospace

The aviation sector has an enormous carbon footprint and is responsible for around 12% of all transport emissions. Over the past few years, the industry has been under pressure to slash carbon emissions and step up in the fight against climate change. While sustainable biofuels are a good solution, engineers have also set their sights on electric aircraft. Of course, battery-powered aircraft present a unique et of challenges.

In Germany, of all-electric aircraft manufacturer Eviation is pushing the limits of battery-powered technology.  The company recently launched its highly anticipated Eviation Alice, a battery-powered plane that boasts a range of 250 nautical miles, maximum operating speed of 260 knots true airspeed (KTAS) and maximum payload of 2500 LBS. With zero carbon emissions, the Eviation Alice sets a new bar for sustainable aviation.

An advanced battery management system played a pivotal role in helping Eviation achieve these impressive figures. The BMS is also a critical part of the plane’s safety system and monitors parameters like power demand, energy supply and temperature. This eliminates the risk of battery fires and keeps passengers safe in the sky.

“Today we embark on the next era of aviation - we have successfully electrified the skies with the unforgettable first flight of Alice,” says Gregory Davis, Eviation CEO. “People now know what affordable, clean and sustainable aviation looks and sounds like for the first time in a fixed-wing, all-electric aircraft. This ground-breaking milestone will lead innovation in sustainable air travel, and shape both passenger and cargo travel in the future.”

Energy Storage

Batteries offer incredible potential as energy storage solutions. However, the performance and service life of battery packs is limited by the weakest cell in the group. Smart battery management systems allow operators to monitor the health of individual cells, as well as the overall system.

As the world acts on issues like air pollution and climate change, smart batteries will play a critical role in electrifying the transport sector and reducing greenhouse gas emissions. Environmental scientists are also exploring new ways to address emissions linked to food loss and waste. Find out more from experts Dr. Raj Shah and Ms. Aaliyah Kaushal in ‘The Effects of Food loss and Waste (FLW) on Greenhouse Gas (GHG) Emissions’.