Electrical Industrial Apparatus
Improve in-situ life prediction and classification performance by capturing both the present state and evolution rate of battery aging
Zhao, Mingyuan, Zhang, Yongzhi
This study develops a methodology by capturing both the battery aging state and degradation rate for improved life prediction performance. The aging state is indicated by six physical features of an equivalent circuit model that are extracted from the voltage relaxation data. And the degradation rate is captured by two features extracted from the differences between the voltage relaxation curves within a moving window (for life prediction), or the differences between the capacity vs. voltage curves at different cycles (for life classification). Two machine learning models, which are constructed based on Gaussian Processes, are used to describe the relationships between these physical features and battery lifetimes for the life prediction and classification, respectively. The methodology is validated with the aging data of 74 battery cells of three different types. Experimental results show that based on only 3-12 minutes' sampling data, the method with novel features predicts accurate battery lifetimes, with the prediction accuracy improved by up to 67.09% compared with the benchmark method. And the batteries are classified into three groups (long, medium, and short) with an overall accuracy larger than 90% based on only two adjacent cycles' information, enabling the highly efficient regrouping of retired batteries.
1.5 million materials narratives generated by chatbots
Park, Yang Jeong, Jerng, Sung Eun, Park, Jin-Sung, Kwon, Choah, Hsu, Chia-Wei, Ren, Zhichu, Yoon, Sungroh, Li, Ju
The advent of artificial intelligence (AI) has enabled a comprehensive exploration of materials for various applications. However, AI models often prioritize frequently encountered materials in the scientific literature, limiting the selection of suitable candidates based on inherent physical and chemical properties. To address this imbalance, we have generated a dataset of 1,494,017 natural language-material paragraphs based on combined OQMD, Materials Project, JARVIS, COD and AFLOW2 databases, which are dominated by ab initio calculations and tend to be much more evenly distributed on the periodic table. The generated text narratives were then polled and scored by both human experts and ChatGPT-4, based on three rubrics: technical accuracy, language and structure, and relevance and depth of content, showing similar scores but with human-scored depth of content being the most lagging. The merger of multi-modality data sources and large language model (LLM) holds immense potential for AI frameworks to help the exploration and discovery of solid-state materials for specific applications.
An interpretable deep learning method for bearing fault diagnosis
Lu, Hao, Bray, Austin M., Hu, Chao, Zimmerman, Andrew T., Xu, Hongyi
Deep learning (DL) has gained popularity in recent years as an effective tool for classifying the current health and predicting the future of industrial equipment. However, most DL models have black-box components with an underlying structure that is too complex to be interpreted and explained to human users. This presents significant challenges when deploying these models for safety-critical maintenance tasks, where non-technical personnel often need to have complete trust in the recommendations these models give. To address these challenges, we utilize a convolutional neural network (CNN) with Gradient-weighted Class Activation Mapping (Grad-CAM) activation map visualizations to form an interpretable DL method for classifying bearing faults. After the model training process, we apply Grad-CAM to identify a training sample's feature importance and to form a library of diagnosis knowledge (or health library) containing training samples with annotated feature maps. During the model evaluation process, the proposed approach retrieves prediction basis samples from the health library according to the similarity of the feature importance. The proposed method can be easily applied to any CNN model without modifying the model architecture, and our experimental results show that this method can select prediction basis samples that are intuitively and physically meaningful, improving the model's trustworthiness for human users.
GM's latest investment could speed development of cheaper EV batteries
To make its Ultium EV program a success, GM is counting on battery innovations to make the technology simpler and cheaper. As part of that program, the automaker has boosted its investment with Mitra Chem --a company focused on building batteries in the US using iron-based cathodes -- via a new $60 million financing round. "This is a strategic investment that will further help reinforce GM's efforts in EV batteries, accelerate our work on affordable battery chemistries like LMFP and support our efforts to build a US-focused battery supply chain," said GM VP Gil Golan. Mitra Chem is more of a battery development company than a manufacturer. It uses AI to "simulate, synthesize and test thousands of cathode designs monthly, ranging in size from grams to kilograms," the press release states.
Cerberus: A Deep Learning Hybrid Model for Lithium-Ion Battery Aging Estimation and Prediction Based on Relaxation Voltage Curves
Xiang, Yue, Jiang, Bo, Dai, Haifeng
The degradation process of lithium-ion batteries is intricately linked to their entire lifecycle as power sources and energy storage devices, encompassing aspects such as performance delivery and cycling utilization. Consequently, the accurate and expedient estimation or prediction of the aging state of lithium-ion batteries has garnered extensive attention. Nonetheless, prevailing research predominantly concentrates on either aging estimation or prediction, neglecting the dynamic fusion of both facets. This paper proposes a hybrid model for capacity aging estimation and prediction based on deep learning, wherein salient features highly pertinent to aging are extracted from charge and discharge relaxation processes. By amalgamating historical capacity decay data, the model dynamically furnishes estimations of the present capacity and forecasts of future capacity for lithium-ion batteries. Our approach is validated against a novel dataset involving charge and discharge cycles at varying rates. Specifically, under a charging condition of 0.25C, a mean absolute percentage error (MAPE) of 0.29% is achieved. This outcome underscores the model's adeptness in harnessing relaxation processes commonly encountered in the real world and synergizing with historical capacity records within battery management systems (BMS), thereby affording estimations and prognostications of capacity decline with heightened precision.
Estimating and Incentivizing Imperfect-Knowledge Agents with Hidden Rewards
Dogan, Ilgin, Shen, Zuo-Jun Max, Aswani, Anil
Repeated principal-agent theory is a well-established paradigm that studies sequential interactions between two self-interested decision-makers. In particular, it offers a framework to analyze the problem of a primary party (i.e., principal) in a system who seeks to optimize the ultimate performance of the system by repeatedly delegating some operational control to another strategic party (i.e., agent) with a private decision-making process. This privacy imposes an information asymmetry between the principal and the agent that can appear as either an adverse selection setting, in which the information about the agent's true preferences or rewards are hidden from the principal, or a moral hazard setting, in which the actions chosen by the agent are hidden from the principal (Bolton and Dewatripont 2004). In either case, the principal's problem can be defined along two main dimensions: i) learning some private information about the agent by training a consistent estimator, ii) designing an incentive mechanism to lead the agent's algorithm in favor of the principal. In this paper, we study these two research problems for an unexplored adverse selection setting by marrying the classical principal-agent theory to statistics and reinforcement learning. In a repeated principal-agent game, the main theoretical challenge is sourced from the dynamic and sequential interactions taking place between the two strategic decision-makers. In each play of the game, first the principal offers a menu of incentives to the agent, and then the agent makes a choice from a finite set of actions, which in turn determines the rewards collected by both players. In other words, there is a two-sided sequential externality in this setting, whereby the agent's imperfect knowledge imposes additional costs on the principal and the principal's incentives impose a more challenging decision-making environment for the agent with imperfect knowledge. This paper considers that both the principal and the agent observe stochastic rewards with unknown (to both) expectations, and that both parties aim to maximize their own cumulative expected rewards Dogan et.
Tightly-coupled Visual-DVL-Inertial Odometry for Robot-based Ice-water Boundary Exploration
Zhao, Lin, Zhou, Mingxi, Loose, Brice
Robotic underwater systems, e.g., Autonomous Underwater Vehicles (AUVs) and Remotely Operated Vehicles (ROVs), are promising tools for collecting biogeochemical data at the ice-water interface for scientific advancements. However, state estimation, i.e., localization, is a well-known problem for robotic systems, especially, for the ones that travel underwater. In this paper, we present a tightly-coupled multi-sensors fusion framework to increase localization accuracy that is robust to sensor failure. Visual images, Doppler Velocity Log (DVL), Inertial Measurement Unit (IMU) and Pressure sensor are integrated into the state-of-art Multi-State Constraint Kalman Filter (MSCKF) for state estimation. Besides that a new keyframe-based state clone mechanism and a new DVL-aided feature enhancement are presented to further improve the localization performance. The proposed method is validated with a data set collected in the field under frozen ice, and the result is compared with 6 other different sensor fusion setups. Overall, the result with the keyframe enabled and DVL-aided feature enhancement yields the best performance with a Root-mean-square error of less than 2 m compared to the ground truth path with a total traveling distance of about 200 m.
Two-stage Early Prediction Framework of Remaining Useful Life for Lithium-ion Batteries
Mittal, Dhruv, Bello, Hymalai, Zhou, Bo, Jha, Mayank Shekhar, Suh, Sungho, Lukowicz, Paul
Early prediction of remaining useful life (RUL) is crucial for effective battery management across various industries, ranging from household appliances to large-scale applications. Accurate RUL prediction improves the reliability and maintainability of battery technology. However, existing methods have limitations, including assumptions of data from the same sensors or distribution, foreknowledge of the end of life (EOL), and neglect to determine the first prediction cycle (FPC) to identify the start of the unhealthy stage. This paper proposes a novel method for RUL prediction of Lithium-ion batteries. The proposed framework comprises two stages: determining the FPC using a neural network-based model to divide the degradation data into distinct health states and predicting the degradation pattern after the FPC to estimate the remaining useful life as a percentage. Experimental results demonstrate that the proposed method outperforms conventional approaches in terms of RUL prediction. Furthermore, the proposed method shows promise for real-world scenarios, providing improved accuracy and applicability for battery management.
Vocab-Expander: A System for Creating Domain-Specific Vocabularies Based on Word Embeddings
Färber, Michael, Popovic, Nicholas
In this paper, we propose Vocab-Expander at https://vocab-expander.com, an online tool that enables end-users (e.g., technology scouts) to create and expand a vocabulary of their domain of interest. It utilizes an ensemble of state-of-the-art word embedding techniques based on web text and ConceptNet, a common-sense knowledge base, to suggest related terms for already given terms. The system has an easy-to-use interface that allows users to quickly confirm or reject term suggestions. Vocab-Expander offers a variety of potential use cases, such as improving concept-based information retrieval in technology and innovation management, enhancing communication and collaboration within organizations or interdisciplinary projects, and creating vocabularies for specific courses in education.
Exploring Different Time-series-Transformer (TST) Architectures: A Case Study in Battery Life Prediction for Electric Vehicles (EVs)
Sitapure, Niranjan, Kulkarni, Atharva
In recent years, battery technology for electric vehicles (EVs) has been a major focus, with a significant emphasis on developing new battery materials and chemistries. However, accurately predicting key battery parameters, such as state-of-charge (SOC) and temperature, remains a challenge for constructing advanced battery management systems (BMS). Existing battery models do not comprehensively cover all parameters affecting battery performance, including non-battery-related factors like ambient temperature, cabin temperature, elevation, and regenerative braking during EV operation. Due to the difficulty of incorporating these auxiliary parameters into traditional models, a data-driven approach is suggested. Time-series-transformers (TSTs), leveraging multiheaded attention and parallelization-friendly architecture, are explored alongside LSTM models. Novel TST architectures, including encoder TST + decoder LSTM and a hybrid TST-LSTM, are also developed and compared against existing models. A dataset comprising 72 driving trips in a BMW i3 (60 Ah) is used to address battery life prediction in EVs, aiming to create accurate TST models that incorporate environmental, battery, vehicle driving, and heating circuit data to predict SOC and battery temperature for future time steps.