The performance and safety evaluation of electric vehicle (EV) batteries is a multifaceted process that extends beyond reliance on a single key performance indicator. Instances of electric buses breakdowns or fires typically stem from a culmination of factors rather than a singular event.

These contributing events can gradually lead to performance degradation before eventually leading to battery failure or thermal runaway. Examples of potential performance degradation or fire risks encompass the limitations of battery management systems, and the emergence of temperature and voltage spreads as the battery undergoes ageing.

Make sure your buses are performing well from day one

Every electric bus lithium-ion battery is equipped with a Battery Management System (BMS) that actively monitors and regulates battery operations. The primary role of the BMS is to guarantee the secure functioning of the battery. It oversees critical parameters, such as maintaining each battery cell within safe voltage, current, and temperature limits during charging, discharging, and open circuit conditions. The BMS is designed to intervene and cut power in case of issues, preventing potential worst-case scenarios. On the other hand, while performing its safety functions, BMS can also provide State of Health (SOH) and State of Charge (SOC) indicators.

To achieve optimal performance, regular reassessment of these battery State of Health (SOH) and State of Charge (SOC) indicators is imperative. Accurate measurements not only unveil potential issues with Battery Management System (BMS) calibration but also establish a foundation for reliable fleet operations. Fleet operators can rely on these indicators to fine-tune their electric bus operations, enhancing efficiency and extending the overall lifespan of their valuable assets.

Unveiling potential issues with Battery Management System (BMS) calibration is of paramount importance in the seamless operation of electric bus fleets. During the commissioning phase, the precision and accuracy of the BMS are critical parameters to verify to ensure optimal battery performance and safety. Battery analytics play a crucial role in this context by actively monitoring and analyzing BMS data, allowing for the early detection of calibration discrepancies.

In the example provided (Figure 1), recently commissioned buses display irregular State of Health (SOH) degradation. Regrettably, it took the operator over six months to identify the issue and engage with the manufacturer, resulting in a period of blind operation during this timeframe.

Identifying these issues at an early stage enables bus operators to proactively engage with their asset providers and OEM, advocating for necessary software updates and fine-tuning to rectify calibration inaccuracies. This proactive approach not only enhances the reliability of the electric bus fleet but also fosters a culture of continuous improvement, ensuring that BMS calibration remains optimized throughout the operational lifespan of the vehicles.

Predict how your buses are going to age

As we delve into the nuances of maintaining peak performance, it becomes evident that the heartbeat of any electric bus fleet lies in the precision of its battery degradation monitoring. These indicators not only fine-tune systems but also set the stage for the seamless operation of these eco-friendly giants.

We now explore predictive tools, with a focus on Remaining Useful Lifetime (RUL). RUL acts as a predictive tool for fleet managers, enabling them to anticipate and prevent potential issues in battery health. Through simulating battery degradation based on specific usage profiles, fleet managers gain valuable insights. This foresight aids in strategic maintenance planning, reducing downtime and optimizing overall fleet performance.

In Figure 2, the comparison illustrates the aging patterns of 7 similar electric buses subjected to varying operational conditions. In this case, low temperatures tent to accelerate battery aging whereas in other cases, high temperatures highly impact battery degradation. Anyway, the discernible temperature variations prompt a need for analysis to differentiate between conditions imposed by regular operations and those stemming from potential issues in the battery system architecture.

Prevent battery safety issue

As we shift from meticulous battery health monitoring to predictive analytics, the focus turns from reactive to proactive fleet management. The integration of predictive tools transforms the approach, empowering fleet operators not just to address but to anticipate and mitigate issues before affecting operations.

The importance deepens as we delve into the critical role of early detection in averting safety concerns. In the intricate operations of electric buses, subtle cell imbalances and potential battery failures are concealed challenges. Here, battery analytics function as vigilant guardians, recognizing warning signs before they evolve into performance issues or safety incidents. The capacity to act on early indicators becomes a pivotal factor, enhancing both reliability and safety significantly.

Conclusion

In the complex landscape of electric bus operations, a cohesive approach integrates proactive monitoring, predictive planning, and early issue identification. Battery analytics stand out as instrumental contributors, addressing intricate challenges. The ongoing vigilance in monitoring battery health, the strategic use of predictive tools, and the timely identification of potential issues collectively reshape the operational landscape of electric bus fleets. As sustainability and safety become central in urban transportation, the influence of battery analytics becomes a driving factor, guiding electric buses toward a future where intelligence, foresight, and reliability meet operational challenges.

In the final article, we will focus on the second life management of electric buses batteries: how to overcome costs-benefits tradeoffs and monetize the batteries on the second life market?

The post Unleash the potential of your eBuses batteries, by PowerUp appeared first on Sustainable Bus.

As urban centers face mounting pressure to reduce greenhouse gas emissions, the electrification of bus fleets emerges as an increasingly efficient and sustainable urban planning initiative. Electric buses not only contribute to a diminished operational carbon footprint but also offer enticing benefits such as reduced operating costs (savings on fuel and maintenance expenses) and enhanced passenger comfort. Consequently, they are poised to play a pivotal role in the transition of fleet managers toward high-value, low-carbon operations.

Yet, the widespread adoption of electric buses faces a notable obstacle: the limited driving range in comparison to their internal combustion engine (ICE) counterparts. This constraint presents a significant challenge for fleet operators, whose success hinges on the optimized utilization of their assets.

However, far from accepting this limitation as inevitable, there are two scalable strategies that can be employed to surmount this hurdle:

1. Implementation of intelligent charging infrastructure, tailored to the unique needs of buses and the strategic goals of fleet management.
2. Rigorous monitoring of battery state-of-charge (SOC) and battery capacity degradation over time.

Reading between the lines, the effective execution of these strategies entails a comprehensive approach to battery data. This data is swiftly becoming the catalyst for controlling battery performance. It represents the key ingredient in transforming ‘black box’ batteries installed in buses into actionable insights that drive improved performance, reduced maintenance costs, and optimized battery life cycles.

Data collection

To harness the power of battery data, fleet operators must first collect it effectively. There are three primary scenarios for collecting data from an electric bus’s battery and integrating it into the Intermodal Transport Control System (ITCS):

1. Manufacturer-Installed Telematics: Some manufacturers equip their electric buses with telematic systems that gather data from various sensors, including the battery. This data is then accessible to fleet operators through APIs or central service portals, contingent on the manufacturer’s agreement.

• Third-Party Telematics: In the absence of manufacturer-installed telematics, fleet operators can turn to third-party providers who install external telematics modules on buses. These modules collect data from the vehicle interfaces, typically the Controller Area Network (CAN) bus, and send it to a central system. Fleet operators can access this data via APIs.

• On-Board Unit (OBU) Integration: Another approach involves using the fleet operator’s ITCS OBU to directly retrieve data from the vehicle interfaces and transfer it to the ITCS server for further processing.

Regardless of the data collection scenario, adopting open standards, such as the Telediagnostic for Intelligent Garage in Real-time (TiGR) protocol, or at least homogeneous way of collecting data is crucial. It ensures flexibility, prevents vendor lock-in, and facilitates interoperability among IT systems in public transport.

Data Requirements

Determining specific data requirements is essential for effective data collection. Key data points include voltage (U), current (I), and temperature (T), as these are fundamental for battery analytics. Minimum and maximum cell voltage and cell temperature are also critical for detecting cell imbalance-related anomalies. These parameters directly impact battery performance and capacity loss, enabling early detection and preventive action.

The upcoming article will explore how to enhance battery performance and capacity by relying on dependable and precise battery health and safety indicators.

Data Cleansing & Processing

Even with access to data, it must undergo rigorous cleansing and processing to yield valuable insights. Data quality and management face challenges related to data volume, errors in Battery Management System (BMS) measurements, and communication failures on electric buses. The raw battery operation data is filtered, standardized, and validated, with checks for anomalies and data gaps based on battery usage profiles. The result is a reliable dataset that fuels degradation and safety algorithms.

• Effective data cleansing and processing enable smooth algorithm performance, leading to:
• Reduced operation and maintenance costs
• Extended longevity of electric bus fleets by minimizing downtime
• Early detection of battery hazards, preventing potential fire incidents

Battery Insight® cloud-based battery analytics strives to deliver these benefits.

Conclusion

Electric buses are the future of urban transportation, offering sustainability and cost-efficiency benefits. To unlock their full potential, fleet operators and integrators must prioritize battery data collection and analysis:

• Gain access to the right data through telematics systems or onboard units’ providers.
• Promote global IT communication standards for interoperability.
• Employ high-quality data cleansing processes, to ensure algorithms receive accurate and reliable data.
• Battery analytics is key to optimizing electric bus fleet performance and ensuring a sustainable and low-carbon future for urban transportation.

In the upcoming article, we will delve into how battery analytics can extract value from battery data. We will present real-world examples demonstrating how battery analytics can enhance your financial performance and grant you a competitive advantage in the ever-evolving mobility market.

The post Unleashing value with battery analytics in the mobility revolution, by PowerUp appeared first on Sustainable Bus.

In the culmination of our series on advanced battery analytics for electric bus operations, it is time to take on the second-life management topic. This final piece underlines the critical role of battery analytics in effectively navigating the complexities of monitoring battery degradation, conducting safety audits, and evaluating the eligibility of batteries for second-life applications.

Over the past decade, the electric car market has witnessed a steady growth, coinciding with the average lifespan of batteries, which is also around 10 years. While two-thirds of a battery’s environmental footprint occurs during the phases of production and end-of-life, it is imperative to discuss ‘lifespans’ in the plural to extend their usage and fulfill the promises of impact reduction.

To postpone the inevitable moment of recycling and surpass the production/destruction paradigm, the option of reuse must be considered at its true value. This approach demands a more enlightened management of the first life of batteries and appropriate redirection in their second life.

How to make the most of a battery capacity and still be able to monetize it for second life?
Are second-life batteries safe and reliable enough to be used?

When batteries reach around 80% of their capacity, they are typically considered ‘end of life’ for their initial use. However, these batteries often remain suitable for other applications, marking the beginning of their second life. Numerous solutions for their reuse are already in development, with Battery Energy Storage Systems (BESS) projects increasingly incorporating electric bus or other EV batteries. Unlike electric vehicles, BESS projects benefit from fewer space or weight limitations, allowing for the stacking of hundreds of battery packs or racks to store energy.

1. Prevent knee-point

Even though it is dependent on usage, batteries typically degrade slowly in the first part of their life: batteries usually lose only a few percents of their capacity in their first years of operation.

However, aging is a nonlinear phenomenon: at some point, the trend drastically changes, and a steep drop of SOH can be witnessed in a limited time window (several percents in a few weeks). This trend change is called a knee-point (see figure 1), and this brutal acceleration of the capacity loss can precipitate the need of maintenance, or even paralyze a whole system if not detected early on.

But how to determine the right time to put an end to battery pack usage and monetize it for second life? Understanding the nuances of battery degradation is first paramount to detect knee-point stage and optimize second life management. Battery analytics, armed with the ability to analyze usage profiles and chemistry specifics, play a crucial role in finely monitoring battery degradation and predicting batteries lifetime of batteries. This proactive approach allows for strategic decision-making, ensuring that batteries are repurposed at the right time and at the right price.

2. Estimate the best price

Examining a real use-case involving 4 electric buses with LFP 258 kWh batteries, monitored by PowerUp for five years, reveals a degradation of 6 to 8% of their SOH. These batteries are estimated to reach their End of Life (EoL) starting from year 17 for the less performing and year 22 for the most performing.

Combining Remaining Useful Life (RUL) predictions with knee-point detection allows fleet managers to determine the optimal time to sell batteries. Companies like Cling Systems or Circunomics can also perform estimations of battery value based on demand, price per kWh, and the critical variable of SOH at specific dates.

3. Ensure the safety

The qualification of batteries for a second life is contingent upon a meticulous safety audit. Battery Management Systems (BMS) latest collected data is not enough as it may overlook certain issues such as lithium plating formation or advanced cell imbalances. Once again, battery analytics step in as the vigilant eye, pinpointing potential safety concerns that might have been missed. This ensures that only batteries meeting stringent safety criteria move forward into their second life.

Conclusion

As we conclude our exploration into advanced battery analytics for electric bus operations, the spotlight on second-life management reveals a landscape where predictive insights, safety audits, and market-driven estimations converge.

Battery analytics emerge as indispensable tools, shaping the future of sustainable energy storage. Through a holistic approach, we pave the way for a robust second life for electric bus batteries, proving that their value extends far beyond their initial deployment.

The post How to make the most of a battery capacity and still be able to monetize it for second life? appeared first on Sustainable Bus.