11 myths about electric car batteries

In recent years, electric vehicle technology, especially its battery technology, has developed rapidly. This article will explore the 11 most common misconceptions about electric vehicle (EV) batteries, one of the most promising new technologies in the automotive industry, and their relevance to wireless battery management systems (BMS).

EV batteries are considered extremely complex, a perception that stems from their early development stages and the multitude of new battery cells and other systems surrounding them in the car, including the battery management system (BMS). However, over time, EV batteries have become less complex, and many components that were once new to the automotive industry are now commonplace and have proven reliability.

Although batteries still represent a high degree of engineering complexity, continued technological advances are making them easier to design, use, and understand. Innovations in battery chemistry, manufacturing processes, and even fundamental changes in battery architecture are helping to reduce their complexity.

The idea that battery modules are an integral part of battery design is being re-examined as next-generation architectures emerge. Historically, battery systems have used modules as the basic building blocks and assembled them into larger battery packs.

However, emerging cell-to-pack and cell-to-chassis designs are challenging this traditional approach. Cells are being integrated directly into the vehicle structure, increasing energy density, increasing available space, and significantly reducing weight and material consumption.

While there have been several high-profile and well-publicized incidents of electric vehicle batteries overheating, they are not inherently unsafe. In fact, such incidents have become extremely rare thanks to the ever-improving designs in modern electric vehicles. These systems are carefully designed to closely monitor the battery's charge, temperature, and overall health, and intervene to prevent an incident if a safety hazard could arise.

Lessons learned from vehicle crashes and battery failures have further improved the safety of electric vehicle batteries, driving advances in technologies such as smart fuses, fault-isolating internal structures, and durable casing materials. These measures, combined with rigorous testing and certification processes, ensure that electric vehicle batteries meet high functional safety standards before they are put on the market.

Improving the level of monitoring also helps enhance safety. For example, by adopting a cell-level monitoring system, a temperature sensor can be installed in each cell instead of sharing one for several cells. In this way, if a cell is damaged or has a defect that causes an abnormal increase in temperature, it can be identified more quickly.

Thanks to advances in technology and a better understanding of battery cell performance, the lifespan of electric vehicle batteries continues to improve with each generation of technology. Today’s electric vehicle batteries are designed to last, with many manufacturers offering warranties of up to ten years, underscoring their confidence in the technology.

And, EV battery life is being extended thanks to continued improvements in chemistry and battery management systems (BMS), which are able to maintain their charge capacity over years and miles of use.

The sustainability of electric vehicle batteries is a major concern. But the EU's Battery Passport and other new regulations aim to address this issue. Improving battery traceability, especially at the cell level, will help promote a more sustainable circular economy.

When electric vehicles reach the end of their useful life, the cell passport can help engineers identify which batteries can still be reused for other applications, such as grid energy storage or renewable energy storage, which require less peak performance than vehicle use.

A deeper understanding of the cell’s history, state of health (SOH), and chemistry will also help reduce waste and promote safer and more responsible recycling practices when batteries reach their end-of-life (EOL) phase. As a result, we are better able to recover the valuable resources embedded in EV cells and ensure they are reused.

While wireless BMS offers design flexibility and improved reliability by eliminating complex wiring, it can also introduce new challenges. These include ensuring signal propagation through the metallic battery pack and preventing radio frequency (RF) interference caused by high-power cables from interrupting wireless communication with the host microcontroller (MCU).

Unlike far-field wireless communication, in the near-field contactless architecture, the signal is only transmitted over a short distance between the battery monitoring chip and the top-mounted bus antenna. Compared with far-field solutions, near-field communication provides higher reliability, and the communication protocol guarantees data synchronization even in challenging RF environments.

Advances in communication protocols and architectures suggest that wireless communication in batteries can mitigate security risks. While concerns about cybersecurity do arise when implementing wireless communications in vehicle systems, effective safeguards can prevent unauthorized access and data breaches.

By using secure and encrypted communication protocols, data access can be effectively restricted. However, simply limiting the range of wireless signals to a few centimeters effectively eliminates any security risk. It is almost impossible for hackers to intercept these signals unless the battery is physically disassembled.

The health status of electric vehicle batteries refers to the performance and capacity retention of the battery throughout its life cycle. SOH (State of Health) is usually used to characterize the health status of the battery. SOH represents the current battery's ability to store electrical energy compared to a new battery and is a parameter that characterizes battery degradation. The health status of the battery is crucial to the range and overall performance of electric vehicles, and directly affects the vehicle's user experience and safety.

Typically, once a battery is retired, its SOH information is lost, requiring a time-consuming and costly assessment if the battery pack is to be reused or recycled. In addition, SOH is usually assessed at the pack level or module level, which may mask problems occurring in individual battery cells.

The battery pack is usually the most expensive component in an electric vehicle, and automakers (OEMs) face the challenge of reducing its cost. Although battery costs will continue to decline as battery design and process optimizations are made, technological changes can also significantly reduce bill of materials (BOM) costs.

Beyond that, cell-level “passporting” not only creates better opportunities for secondary use of batteries, it also makes recycling more efficient, which will help reduce raw material costs.

Safety regulations make the transportation of lithium-ion batteries (Li-ion) expensive, especially when the battery's state of health (SOH) is unknown. When a battery cell is removed from its original battery pack, its SOH is lost and it must be treated as potentially hazardous.

However, new regulations such as the EU Battery Passport can help alleviate these concerns. The Battery Passport is a digital record of the battery's history and SOH that improves safety and transparency during transportation and handling. The information it provides can reduce insurance and transportation costs and mitigate unforeseen risks by providing an accurate assessment of the battery's condition during transportation.

By incorporating cell-level monitoring, you can further enhance this insight, providing data for each individual cell, not just the module or pack. This ensures that cells can be removed from the pack, more accurately assessed, and shipped with confidence.

Electric vehicle batteries are inherently difficult to assemble, as they are high-power devices that require the integration of countless wires and sensors while minimizing the package size. Historically, automation in battery manufacturing has been hampered by the need for manual installation of complex wiring harnesses, limiting the speed and cost-effectiveness of production lines. However, new battery architectures, such as contactless battery monitoring technology, simplify this process by replacing complex wiring with a simple, single-antenna design.