The benefits of electric vehicle technology are numerous, including faster acceleration, better power, and higher maximum torque at startup (target specifications based on simulations). With very few moving parts, electric motors are highly reliable, require virtually no maintenance, and provide very precise traction and stability control. They also generate less friction and heat, requiring less cooling capacity and thus being more efficient. Electric vehicles are better in every metric except for battery weight.
Analog Devices (ADI) has developed a groundbreaking technology – the wireless battery management system (wBMS) – which eliminates battery harnesses and related cables, thereby reducing the weight of electric vehicle batteries and improving battery reliability.
To realize its vision of a future of lightweight and all-electric vehicles, Lotus, a leading manufacturer of high-performance cars, has adopted Analog Devices' (ADI) wireless battery management system (wBMS) in its new electric vehicle lineup, which will be delivered over the next five years. ADI and Lotus have collaborated to develop a transformative solution for the electric vehicle industry—a new ultra-lightweight powertrain architecture and wireless battery management system (wBMS)—that enhances design flexibility, scalability, and maintainability. This project aims to help Lotus safely and steadily expand its future electric vehicle platform, and its success will contribute to a more sustainable environment and a lower-carbon planet.
Patrick Morgan, Corporate Vice President of Automotive Electrification and Sustainable Energy at ADI, stated, “Industries around the world are shifting towards new technologies that protect the planet’s environment. Electric vehicles and the embrace of clean energy are rapidly becoming part of our daily lives. We are proud to partner with Lotus to provide our groundbreaking ADI Wireless Battery Management System (wBMS) to their iconic automotive lineup.”
Overview
· company
Lotus was born from one man's "Form through function" philosophy, creating an elegant engineering legend that inspires a new generation of drivers. Lotus is part of Geely Automobile Group, a rapidly growing global automaker, and is committed to building a sustainable, all-electric future.
• Application
Integrate the wireless BMS into the new lightweight architecture of all its future production electric vehicles. Leveraging the complete hardware, software, and security solutions of the wBMS, it maximizes service and maintenance while extending battery life and maintaining vehicle value.
· challenge
Overcoming design and technological limitations, this technology integrates a flexible and scalable wireless BMS into the electric vehicle product line, while reducing weight and complexity and improving battery density and maintainability.
· Target
Partnering with cutting-edge technology companies to address stringent design and engineering challenges, we develop a future line of lightweight, high-performance electric vehicles while ensuring safety, improving reliability, and delivering a dynamic driving experience.
wBMS: Fully Integrated System
ADI's wBMS consists of 40 hardware components. The entire system is integrated with a complete software suite, a robust and secure end-to-end network, and comprehensive battery cell monitoring software, covering both application and security.
Specific components include the ADBMS6815 (capable of accurately measuring the state of charge of battery cells and battery packs), the LT8618 (a compact, high-speed, high-efficiency synchronous single-chip buck switching regulator for power management), and the ADRF8800 (for ensuring stable and reliable wireless connectivity).
Roger Keen, General Manager of ADI's Electric Vehicles Business Unit, stated, "Our latest wBMS product also supports battery recycling and reuse in energy storage systems to support the circular economy. Products offered by our competitors may bundle hardware, but you don't have the software to connect them all. With ADI's wBMS, customers don't need to write software, allowing them to focus on other aspects of vehicle design."
Quick assessment
“How quickly can you get me up and running and testing on the wBMS wireless network? That’s the first question our customers ask us,” said Shane O’Mahony, Product Marketing Engineer at ADI’s Automotive Technology Division. “If it takes months, they’re not willing to do it. We’ve overcome that obstacle.”
ADI's wBMS evaluation kit is ready to use out of the box, allowing customers to quickly set it up and get it running. It is a complete end-to-end wBMS, including multiple boards, software, and cybersecurity. Shane O'Mahony said, "If you need to use components from different vendors to build a system, then just getting the prototyping done can take months."
Lotus: Pursuing lightweight, maintainability, and flexibility
For over 70 years, Lotus has transformed the world of road cars and racing. The automaker aims to maintain its leading position in the high-performance vehicle segment and become a pioneer in electrification by leveraging ADI's groundbreaking wBMS technology.
In 2020, during the global pandemic, Lotus approached Analog Devices (ADI) engineers regarding its future production electric vehicle lineup. Lotus actively sought collaboration, adopting ADI's wireless battery management system (wBMS) in its new lightweight, high-performance road car. ADI did more than just provide a lightweight wBMS; it also ensured seamless integration with the high-performance automaker's core maintenance and flexible operating model.
The two sides then discussed Lotus’s lightweight electric vehicle powertrain architecture and how ADI’s wBMS can help simplify design and reduce complexity, and achieve further weight reduction.
Wireless BMS (wBMS) is a truly transformative technology for the automotive industry, eliminating the need for battery wiring harnesses and the large number of wires and connectors associated with standard wired BMSs. Analog Devices' wireless BMS reduces battery pack wiring by 90% and battery pack size by 15%. Eliminating cables reduces vehicle weight, lowers material costs, and improves battery safety, reliability, and maintainability. Roger Keen stated, "The elimination of wiring harnesses allows Lotus to offer performance-optimized lightweight solutions that align with its brand image."
cooperate
ADI's technical experts collaborated with Lotus's design engineers to integrate wBMS into the electric vehicle manufacturer's new powertrain architecture, which they call LEVA (Lightweight Electric Vehicle Architecture).
Richard Lively, Director of Powertrain and Chassis Engineering at Lotus, said: “We have worked closely with ADI to integrate the wireless BMS into our new lightweight electric vehicle architecture, which will be the basis for all future Lotus electric vehicles. The wireless BMS eliminates traditional wiring harnesses, enabling Lotus to provide lightweight solutions that optimize vehicle performance and align with our brand philosophy of ‘superior performance through superior technology’.”
Design flexibility is key to success. ADI perfectly met Lotus's requirements. With the wBMS, faster and easier battery reconfiguration designs were achieved, battery pack assembly was optimized, and the manufacturing process was simplified. The wireless nature of the battery management system provided Lotus with design versatility, allowing Lotus to more effectively expand its future electric vehicle lineup.
Due to the impact of the COVID-19 pandemic, on-site collaboration between Lotus and Analog Devices' design and engineering teams was also limited. However, Lotus and Analog Devices were not deterred by this; they interacted through teleconferences, advanced collaboration software, and step-by-step video conferencing.
Flexible LEVA architecture
Lotus's LEVA powertrain architecture is designed specifically for mid-engine, high-performance vehicles. The driver sits in the front, behind the center console and steering wheel. All other components are located behind the driver. Most of the vehicle's weight is distributed in the middle of the four axles, improving weight distribution, stability, and handling. This design also offers advantages such as increased safety and reduced wear. Lotus will utilize LEVA's flexible architecture in other vehicle designs and future production models.
Lightweight vehicles will compete with heavyweight vehicles.
Innovative engineering and groundbreaking technology enabled Lotus to achieve outstanding performance through lightweighting. Reducing the weight of the car is an effective way to establish a true connection between the driver, the car, and the road. Shane O'Mahony said, "During our collaboration with Analog Devices (ADI), Lotus was primarily responsible for removing cables and achieving lightweighting of all components while maintaining optimized BMS performance."
Removing the cables and connectors reduces vehicle weight by eliminating the battery pack wiring harness. It also improves reliability, as the associated cables and connectors are notorious points of failure. Another benefit of wireless battery packs is greater design flexibility and scalability.
ADI Electric Mobility Marketing Manager Shane O'Mahony emphasized, "Weight is the Achilles' heel of high-performance sports cars."
Flexibility and design freedom
After optimizing the entire vehicle structure to achieve high performance, how should the battery pack be designed?
The flexibility of battery reconfiguration is crucial, especially for engineers working on aerodynamic electric vehicle projects where the exterior design is constantly evolving. The wBMS not only provides Lotus with a quick and easy way to develop versatility, scalability, and optimized performance, but the clearance left after removing wiring harnesses also allows for the installation of more battery packs in new vehicle designs. Where appropriate, more batteries can be installed in the powertrain, thereby improving performance and extending vehicle range.
Roger Keen stated, "Lotus engineers are now free to design cars the way they see fit, rather than designing them as much as possible within the constraints of the battery wiring harness."
Improve monitoring capabilities and security while reducing complexity.
A battery pack contains hundreds or even thousands of battery cells. Connecting each cell to its positive and negative terminals with a wire would be an intricate and daunting task. Therefore, wired battery management systems with limited wiring cannot monitor every single cell. The health of the batteries cannot be measured; it can only be inferred by checking the overall state of charge. Low charge or dead batteries cannot be detected.
In a wireless BMS, a group of battery cells transmits a wireless signal, securely sending data to the cloud and storing it securely. Lotus technicians or local mechanics can use a laptop to access a wealth of information, including the state of charge and health of each parallel battery in the pack. OEMs can easily and quickly upgrade the battery software from headquarters. The wBMS provides Lotus engineers with flexibility and cloud-level network security without adding complexity.
No manual operation required
In traditional wired BMS, there is open space between battery modules, allowing for manual access to connect numerous cables and connectors. Wireless BMS modules, with only two terminals, can be packed more tightly together, increasing density and reducing form factor. The terminals can be easily connected using slim robotic tools.
Robotic assembly has led to higher-density battery packs. In secondary use, robotic battery assembly and disassembly are fast, safe, and accurate, saving electric vehicle manufacturers like Lotus time and money.
"ADI's Director of Automotive Technology, Gina Aquilano, said, "A wireless BMS enables the measurement of battery pack health and robotic assembly and disassembly, ensuring that undercapacitated battery cells can be identified and removed, and that battery packs can be effectively repaired."
Maintainability: Not just for reuse
After years of use, the capacity of wireless battery packs decreases, making them no longer an ideal choice for optimizing the power performance of electric vehicles. At this point, the battery packs can be easily repurposed for clean and sustainable secondary applications, such as energy storage systems with lower requirements and power grids around the world. "Old" electric vehicle batteries can be used to store excess solar and wind energy, thus contributing to the vision of future electrification.
Richard Lively, Director of Powertrain and Chassis Engineering at Lotus, stated, “Replacing the entire battery pack whenever one or more battery cells prematurely lose capacity is an unsustainable business model. Analog Devices’ wBMS provides a quick, simple, and cost-effective solution for our maintainability needs.”
Lotus doesn't set a lifespan for any of its cars, and many models are still on the road as classics 25 or 30 years later, which presents a challenge for the manufacturer. A car with virtually no half-life needs to be kept running "forever" while maintaining excellent battery performance throughout the car's lifespan.
When using a wBMS, the battery module has only two terminals (positive and negative) and is software-programmable, enabling quick online upgrades and making maintenance of road vehicles and racing cars easier and faster. The cell controller and battery module are used together as a maintainable unit, further simplifying service models.
The repair business model is nothing new. From home appliances to dental restoration, repair services are a fundamental cornerstone of virtually every industry today. Electric vehicle battery repair will also present significant opportunities for local mechanics, spare parts distributors, and original equipment manufacturers. Its impact on building a sustainable environment is substantial.
“No other BMS competitor can offer battery repair capabilities like Analog Devices. Maintainability will help differentiate Lotus from other electric vehicle manufacturers and reduce carbon emissions by up to 6 tons,” said Shane O’Mahony. “And it will also help ensure that Lotus owners enjoy decades of high-performance driving pleasure.”
wBMS can identify abnormal battery conditions, facilitating quick battery replacement and thus extending the battery pack's lifespan, saving time and costs.
A sustainable future and an exciting driving experience
Considering that consumers are increasingly focused on environmental protection, and in order to provide longer product lifespans and high performance, ADI and Lotus set lightweight, maintainability and sustainability as their goals when they collaborated.
Innovative engineering work has enabled smaller package size, less wiring, and smaller battery pack volume, as well as a flexible system (spanning multiple designs), making it easier to scale and assemble and disassemble faster and safer. Maintainable batteries offer significant business opportunities for industries and OEMs, while also taking us a step closer to a cleaner, healthier planet.
In its future development, bold innovation and radical thinking will help Lotus take another big step forward.
