A breakthrough in state-of-charge estimation for battery management of electric vehicles
Beijing Institute of Technology Press Co., Ltd
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A strong robust state-of-charge estimation method based on the gas-liquid dynamics model
view moreCredit: GREEN ENERGY AND INTELLIGENT TRANSPORTATION
In the rapidly evolving landscape of electric vehicles (EVs) and large-scale energy storage systems, accurate battery management remains a critical challenge. The state-of-charge (SOC) estimation—essentially how much "fuel" is left in your battery—has long been a complex engineering problem due to the dynamic nature of battery behavior under various conditions. Traditional methods often struggle with initial errors, cumulative inaccuracies, and sparse data collection scenarios, limiting their real-world applicability. This groundbreaking research introduces a novel approach that combines the gas-liquid dynamics model (GLDM) with an advanced filtering algorithm to overcome these persistent challenges.
The researchers from Huaiyin Institute of Technology present remarkable improvements in battery SOC estimation across multiple dimensions:
(1) Exceptional Accuracy: The proposed method achieves a maximum SOC error of just 0.016 (1.6%) under normal conditions—a level of precision critical for reliable EV range estimation.
(2) Unparalleled Error Recovery: When faced with a significant initial error of 50%, the new method corrects itself within just 5 seconds, while conventional approaches require over 100 seconds—a 20-fold improvement in recovery speed.
(3) Resilience to Battery Aging: Even when battery capacity deteriorates to 60% of its original value (a common scenario in aging EVs), the maximum SOC estimation error remains below 0.025 (2.5%), ensuring reliable performance throughout the battery's lifecycle.
(4) Robust Performance with Sparse Data: Unlike traditional methods that rapidly lose accuracy when sampling frequency decreases, the proposed approach maintains a slow linear growth in error. At a sampling period of 24 seconds—far longer than typical systems—the Root Mean Square Error (RMSE) remains at approximately 0.01, demonstrating exceptional stability.
This technological breakthrough opens doors to numerous advancements in electric mobility and energy storage: (1) Extended EV Range Confidence: More accurate SOC estimation means drivers can trust their vehicle's range indicators, reducing "range anxiety" and encouraging broader EV adoption. (2) Optimized Fast-Charging Systems: The method's ability to accurately track battery states could enable more efficient fast-charging protocols that maximize charging speed while preserving battery health. (3) Smart Grid Integration: Large-scale battery storage systems using this technology could provide more reliable grid services, enhancing the integration of renewable energy sources. (4) Next-Generation Battery Management: Future research could extend this approach to different battery chemistries like LiFePO4 and multi-cell battery modules, potentially creating a universal battery management solution. (5) Resource-Efficient Implementation: The computational efficiency of this method makes it suitable for implementation in existing battery management systems without requiring hardware upgrades.
This innovative SOC estimation method represents a significant leap forward in battery management technology. By combining the gas-liquid dynamics model with an advanced dual extended Kalman filter featuring a watchdog function, the research addresses the fundamental challenges that have limited battery management systems for years. As electric vehicles and renewable energy storage continue their rapid growth, this technology promises to enhance reliability, extend usable battery life, and ultimately accelerate our transition to sustainable transportation and energy systems.
Reference
Author: Biao Chen a c, Liang Song b, Haobin Jiang c, Zhiguo Zhao a c, Jun Zhu a, Keqiang Xu a
Title of original paper: A strong robust state-of-charge estimation method based on the gas-liquid dynamics model
Article link: https://www.sciencedirect.com/science/article/pii/S2773153724000458
Journal: Green Energy and Intelligent Transportation
DOI: 10.1016/j.geits.2024.100193
Affiliations:
a Jiangsu Key Laboratory of Traffic and Transportation Security, Huaiyin Institute of Technology, Huai'an 223003, China
b Faculty of Chemical Engineering, Huaiyin Institute of Technology, Huai'an 223003, China
c Automotive Engineering Research Institute, Jiangsu University, Zhenjiang 212013, China
Journal
Green Energy and Intelligent Transportation
Method of Research
Experimental study
Subject of Research
Not applicable
Article Title
A strong robust state-of-charge estimation method based on the gas-liquid dynamics model
Spent EV batteries turbocharge plastic upcycling
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A grave-to-cradle strategy for co-upcycling spent LiFePO4 batteries and PET plastics into high-value BHET monomers via photothermal catalysis.
view moreCredit: ©Science China Press
Building Catalysts from Spent Batteries
At the heart of this strategy is a catalyst made by engineering materials extracted from retired LFP batteries. The research team first separated FePO4 cathodes and graphite anodes from the used cells. The graphite underwent chemical treatment to remove lithium ions and serve as a light-absorbing carrier. The iron was extracted from FePO4 in solution form and then deposited onto the recycled graphite through a controlled impregnation and pyrolysis process.
The resulting FeOX/graphite hybrid combines the broadband light absorption properties of carbon with the catalytic power of iron oxide. High-resolution electron microscopy revealed a uniform dispersion of Fe2O3 nanoparticles across the graphite surface, ensuring efficient light-to-heat conversion and catalysis.
This photothermal catalyst was specifically designed to harness solar energy and generate localized heat, which plays a central role in breaking down polyester chains into valuable monomers. “This is not just a recycling process; it’s an upcycling strategy that turns low-value waste into high-value functional materials,” said Prof. Jinxing Chen, co-corresponding author of the study.
Solar-Powered Depolymerization of PET
To test the real-world applicability of their catalyst, the team conducted experiments using PET plastic—a dominant polyester in global use—under simulated sunlight (0.73 W cm−2). Within 1 hour, PET conversion reached nearly 59%, and monomer (BHET) yield surpassed 39%. These figures represent over threefold and eightfold improvements, respectively, compared to conventional thermal processes operating at the same temperature.
Kinetic analysis confirmed that the enhanced performance stems from localized heating rather than any photochemical effect. Both thermal and photothermal processes followed the same reaction pathway, but the solar-driven system achieved superior efficiency at a lower energy cost.
In extended use tests, the catalyst maintained over 90% of its original efficiency across 15 cycles, underscoring its robustness. “This kind of durability is essential for practical application,” said Prof. Guiling Wang, co-corresponding author from Harbin Engineering University. “We wanted to ensure that the system wouldn’t degrade after repeated use, and it didn’t.”
Proven Viability in Outdoor Solar Conditions
Going beyond lab-scale validation, the team designed an outdoor photothermal reactor powered by natural sunlight and equipped with a Fresnel lens to concentrate solar rays. Under field conditions, the system heated the reaction medium to over 190 °C and achieved 99.8% PET conversion within 30 minutes. It yielded 39 grams of high-purity monomers from the test sample—a recovery rate of over 94%.
The system was also tested with real-world post-consumer PET waste, including colored bottles, packaging films, textiles, and plastic lunch boxes, many of which contain pigments, fillers, or mixed polymers. Even under these conditions, the catalyst showed excellent activity and selectivity, demonstrating its potential to process heterogeneous waste streams.
From Concept to Commercial Viability
To evaluate economic feasibility, the researchers performed a full techno-economic analysis (TEA) using Aspen Plus software. Their model assumed an industrial-scale plant processing 100,000 tons of PET annually. With a minimum selling price (MSP) of $1.003 kg−1 for the recovered BHET—12% lower than the average price of virgin monomers—the process proved financially viable.
Furthermore, the energy consumption for photothermal glycolysis was significantly lower than that of conventional thermal routes, leading to a reduction of 34,474 tons of CO2-equivalent greenhouse gas emissions per year. The process also decreased other air pollutants like acidic gases by over 83 tons.
“The economic advantage here is not just in the lower product cost,” Prof. Chen emphasized. “By integrating solar energy and waste-to-resource principles, we also cut emissions and environmental impact, which are increasingly important for policy and industry.”
A Platform for Circular Innovation
The implications of this dual-waste strategy extend beyond just one type of plastic or battery chemistry. The modular design of the catalyst synthesis process allows it to adapt to different battery materials and plastic types, suggesting wide applicability across the recycling industry.
“This is more than a scientific advance—it’s a new framework for how we can think about materials at the end of their life,” said Prof. Wang. “Rather than dismantling everything down to the elemental level, we selectively transform waste into something functionally superior.”
The team proposes several pathways to scale up and further improve the technology: increasing plant capacity, implementing waste heat recovery systems, and optimizing raw material sourcing. Future studies will explore simplified one-pot processes for catalyst fabrication and analyze batteries with various aging conditions to refine performance predictability.
About the Study
The study, entitled Repurposing Spent LiFePO4 Batteries for Sustainable Photothermal-Upcycling of Polyesters, was published in Science China Chemistry. It was led by researchers from the State Key Laboratory of Bioinspired Interfacial Materials Science, Soochow University; the College of Materials Science and Chemical Engineering, Harbin Engineering University; and the Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences.
This work was supported by the National Natural Science Foundation of China, Jiangsu Provincial Fund for Excellent Young Scholars, and other regional innovation and talent programs.
Bridging the gap between solar intermittency and reliable power: Dual-level design extends battery life and optimizes costs
Beijing Institute of Technology Press Co., Ltd
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Dual-level design for cost-effective sizing and power management of hybrid energy storage in photovoltaic systems
view moreCredit: GREEN ENERGY AND INTELLIGENT TRANSPORTATION
In an era where renewable energy is rapidly transforming our power grids, solar photovoltaic (PV) systems face a persistent challenge: the sun doesn't always shine when we need electricity most. Researchers at Aalborg University have developed an innovative solution that could significantly advance how we store and manage solar energy, making renewable power more reliable and cost-effective.
The research team has created a dual-level design approach for hybrid energy storage systems (HESS) that combines lithium-ion batteries with supercapacitors in solar installations. This breakthrough addresses one of the most significant barriers to widespread solar adoption – the intermittent nature of sunlight and the resulting stress on batteries that store solar energy.
The study's results demonstrate remarkable improvements in system performance:
- Battery cycling reduced by up to 13% over a one-year period, significantly extending battery lifespan
- Maintained optimal self-sufficiency of the solar system while reducing operational costs
- Successfully managed power ramp-rate constraints, ensuring grid stability
- Balanced energy throughput between the PV system and the grid for maximum cost-effectiveness
"By intelligently combining lithium-ion batteries with supercapacitors, we're leveraging the strengths of each technology," explains the research team. "Supercapacitors handle the rapid power fluctuations that typically degrade batteries, while the batteries manage longer-term energy storage needs."
The system employs an innovative adaptive filter that dynamically distributes power between batteries and supercapacitors based on real-time conditions. This approach ensures that each component operates within its optimal parameters, extending the overall system life and reducing replacement costs.
The researchers are now looking to expand their work to include additional battery aging factors and validate their findings with real battery cells in field conditions. Future research will also quantify economic benefits more precisely, providing a comprehensive techno-economic analysis. This dual-level design represents a significant step forward in making solar energy more practical and economically viable. By addressing the fundamental challenges of energy storage in renewable systems, the research contributes to accelerating the global transition to clean energy.
As solar installations continue to grow worldwide, innovative approaches to energy storage like this will be crucial in building a more sustainable and resilient energy infrastructure. The combination of smart sizing methodology and adaptive power management demonstrates how thoughtful engineering can overcome the inherent challenges of renewable energy, bringing us closer to a future powered by the sun.
Reference
Author: Xiangqiang Wu, Zhongting Tang, Daniel-Ioan Stroe, Tamas Kerekes
Title of original paper: Dual-level design for cost-effective sizing and power management of hybrid energy storage in photovoltaic systems
Article link: https://www.sciencedirect.com/science/article/pii/S277315372400046X
Journal: Green Energy and Intelligent Transportation
DOI: 10.1016/j.geits.2024.100194
Affiliations:
Department of AAU Energy, Aalborg University, Aalborg 9220, Denmark
Journal
Green Energy and Intelligent Transportation
Method of Research
Experimental study
Subject of Research
Not applicable
Article Title
Dual-level design for cost-effective sizing and power management of hybrid energy storage in photovoltaic systems
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