Since 40% of the price of an electric vehicle depends on its battery, performance and battery life have become key factors in the success of EV brands. As a leader in battery management systems (BMS), Analog Devices (ADI) works with customers to identify best practices in key processes for monitoring and managing electric vehicle batteries and ensuring their safety, productivity, and lifespan.
Overview
• company
Following its acquisition of Linear Technology, ADI's product portfolio included its first integrated high-voltage battery stack monitor, launched in 2008. Since then, we have been committed to providing the highest-performance solutions. Today, we are developing the fifth generation of this product.
• challenge
The growing EV market increasingly requires battery manufacturers, supply chains, and car brands to provide high-quality, reliable battery technologies to meet demand.
• Application
Battery monitoring and management.
• Points of attention
Original equipment manufacturers (OEMs) are very concerned about the safety, cost, efficiency, and lifespan of batteries.
• Target
Improve the BMS to ensure safety, increase reliability, enhance performance, and extend the lifespan of EV batteries.
Invest in a better battery management system
A Battery Management System (BMS) closely monitors, controls, and distributes the reliable charging and discharging of the entire battery system throughout its lifespan. Accurate monitoring of current and voltage distribution is crucial, as overcharging can cause fires or explosions, while undercharging (or complete discharging) leads to battery failure. The quality of the BMS directly impacts the EV's range per charge. A superior BMS maximizes the overall battery lifespan, thereby reducing the cost of ownership.
In this context, price becomes less important, and long-term value becomes the key metric. This is because you're aiming for better performance throughout the battery's entire lifespan. "When it comes to precision, and precision throughout the vehicle's lifespan, there are no trade-offs," says Mike Kultgen, General Manager of ADI BMS. "Higher precision means a better understanding of the battery cell's condition, allowing you to extract more capacity and making the battery pack more reliable." The value of BMS performance is evident considering the investment in the battery pack, and this becomes even more apparent as car designers consider warranties and the lifecycle cost of the battery pack.<sup>1</sup>
Strict requirements for battery management
Batteries place extremely high demands on design teams, as they need to consider a range of priorities, including price, reliability, and safety. When dealing with EV systems that provide voltages from 48 volts to 800 volts, you can't afford to take any risks.
To deliver over 100 kilowatts of electrical energy the moment the driver presses the pedal, the battery system must operate efficiently at hundreds of volts. However, lithium-ion batteries can only provide a few volts. To obtain sufficient power, a large number of batteries need to be connected in series, forming a long battery stack. Typically, an electric vehicle might use 100 individual batteries, providing 350 volts on top of the battery stack. But this presents some challenges.
In a long battery stack, if one battery fails, it's effectively the same as all of them failing. Therefore, you need to monitor and manage all the batteries—charging and discharging them every single day of the vehicle's lifespan. Lithium-ion batteries cannot operate under extreme charge/discharge conditions and must be kept within very specific ranges, such as 15% to 85%, otherwise their performance will degrade.
Monitoring and managing power supply
ADI's BMS provides accurate battery measurement information throughout the entire battery pack lifecycle, from production to end-of-life. Electronics connect directly to each cell in the battery stack, reporting voltage and temperature corresponding to the battery current. The system provides state of charge and state of health. The current and temperature of each cell must be monitored using complex algorithms on a central processing unit. ADI incorporates powerful communication interfaces and supports modular design (architecture). It is fully scalable and suitable for our diverse customer base.
"The BMS continuously monitors the battery, providing reliable measurement accuracy under various temperature and operating conditions. The system knows the status at every moment and relies 100% on the information it receives from the ADI chip."
Mike Kultgen – General Manager of ADI BMS
Key values: accuracy, reliability, and stability
The benefits of working closely with ADI's battery management system experts go beyond just access to a diverse range of components and products. They provide OEMs with our system-level expertise, deep domain knowledge, and years of hands-on BMS design experience. OEMs can improve per-charge driving efficiency, extend battery life, ensure safety, and enhance brand trust.
Patrick Morgan, Vice President of ADI AUTG, said, “Customers tell us they need to trust our products before they use them. So we host technology summits at their sites or in our factories and invite our key designers and application engineers to meet with their teams. We spend a day or two presenting our development plans, understanding the problems they need to solve, and then discussing how we will address their specific issues. We build trust by focusing on collaboration.”
Problem solving, finding solutions
“An Asia-based customer asked us to design a new battery management system around their existing one,” said Cuyler Latorraca, Applications Manager at Analog Devices. “We examined their concept, system requirements, and operating environment. We discovered that their grounding scheme was causing errors in system measurements, a common problem in the industry, and we then took steps to eliminate that error.”
ADI's high-performance BMS powers supercars.
The Rimac C_Two high-performance supercar boasts 1,914 horsepower, accelerates from 0-60 mph in 1.85 seconds, and reaches a top speed of 258 mph. This all-electric supercar showcases Rimac's technological prowess, employing a battery pack composed of 6,960 lithium-manganese nickel cells, fully embodying true innovation and passion.
About 10 years ago, a 21-year-old inventor founded Rimac Automobili in a garage in Croatia. Today, the company has grown into a technology giant with 600 employees. Rimac designs, develops, and manufactures electric supercars and high-performance electrification systems for automotive companies worldwide.
Leveraging Analog Devices' high-precision Battery Management System (BMS) integrated circuits (ICs), Rimac electric vehicles can extract as much energy and charge as possible from the battery through high-precision measurements of the cells. Sophisticated diagnostic technologies enable the system to monitor battery characteristics, voltage, and temperature to determine the state of charge at any time. Patrick Morgan, Vice President of Automotive Electrification and Infotainment at Analog Devices, stated, "High precision directly translates to faster charging times, maximized battery capacity, and extended range."
Rimac CEO Mate Rimac stated, “Rimac is a technology leader in high-performance electric vehicles. We develop and manufacture critical electrification systems for numerous automakers worldwide, while our own supercars set even higher performance standards for electric vehicles. Our battery management system is used in some of the most demanding applications globally, requiring extremely high precision, rapid current and voltage changes over extremely short periods, and fast dynamic adjustments within the battery management control system. We decided to adopt Analog Devices' battery management IC portfolio across our entire product line. We conducted comparative testing of these ICs in the market, and the results confirmed that Analog Devices' products can provide high-precision measurements and product reliability throughout the entire lifecycle of the vehicle, which is why we chose them.”
Looking to the future
“High-voltage battery system technology is advancing rapidly,” said Greg Zimmer, ADI BMS Marketing Manager. “We are under tremendous pressure to increase capacity and extend lifespan. How will the industry achieve this? How can we extract more energy from battery packs, increase driving range, support faster charging, and develop centralized and modular designs while building batteries that can last for 10 years?”
ADI focuses not only on the problems our customers face today, but also on the future and the process of continuous improvement. We will continue to lead the industry by launching solutions that maximize range per charge, reduce overall weight, and lower the total cost of battery systems. Our extensive system-level experience and vast portfolio of components (3 to 18 cells in a single integrated circuit, supporting more battery options than any other competitor) set us apart from the competition.
We haven't reached the pinnacle of BMS yet.
ADI collaborates with original equipment manufacturers (OEMs) to improve how future challenges in power density, accuracy, and weight are addressed and communicated through architectural innovation. We will continue to innovate, and our fifth-generation BMS is expected to enter vehicle production next year.
