Characteristic Prediction and Temperature-Control Strategy under Constant Power Conditions for Lithium-Ion Batteries

Accurate characteristic prediction under constant power conditions can accurately evaluate the capacity of lithium-ion battery output. It can also ensure safe use for new-energy vehicles and electrochemical energy storage. As the battery voltage continues to drop under constant power conditions, the battery current output will accordingly increase, which brings a risk of thermal runaway in instances of weak heat dissipation. Therefore, knowing how to control the battery temperature is very critical for safe use. At present, the model-based method for characteristic prediction and temperature control has been used by most scholars, and that is also the key to this method. This work firstly extends a cell model to a pack-based electrochemical two-dimensional thermal coupling model, considering the heterogeneity of different cells inside the pack, and obtains the model parameters for a prismatic lithium-ion battery with a rated capacity of 42 Ah. Characteristic prediction under constant power conditions is then conducted based on an iterative solution method. Validations of characteristic prediction indicate the convenience of the developed models, with average absolute errors of voltage and temperature less than 36 mV and 0.4 K, respectively, and power error less than 0.005%. Finally, two model-based temperature feed-forward control strategies with lower cooling costs and shorter prediction times were developed based on the battery characteristic predictions, which leaves room for further controller development

Analysis on the Characteristics of Mt. Emei Basalt Rock and Fiber-Used Basalt Deposit in E’bian Area, Sichuan Province

The Permian Emeishan basalt formations exposed in the E’bian area are mostly overflow facies, and the rocks are dark gray to gray-green. According to their genesis and structural composition characteristics, the Emeishan basalts in the E’bian area can be divided into porphyry There are four rock types: compactbasalt, porphyriticbasalt, stomata-almond basalt, and tuffaceous basalt. Research on the rock and chemical characteristics of basalt has been carried out, and the research shows that there is fiber-used basalt in the area that is suitable for drawing, which has a good development and utilization prospect

A closed-loop process for recycling LiNixCoyMn(1âxây)O2 from mixed cathode materials of lithium-ion batteries

With the rapid development of consumer electronics and electric vehicles (EV), a large number of spent lithium-ion batteries (LIBs) have been generated worldwide. Thus, effective recycling technologies to recapture a significant amount of valuable metals contained in spent LIBs are highly desirable to prevent the environmental pollution and resource depletion. In this work, a novel recycling technology to regenerate a LiNi1/3Co1/3Mn1/3O2 cathode material from spent LIBs with different cathode chemistries has been developed. By dismantling, crushing, leaching and impurity removing, the LiNi1/3Co1/3Mn1/3O2 (selected as an example of LiNixCoyMn(1âxây)O2) powder can be directly prepared from the purified leaching solution via co-precipitation followed by solid-state synthesis. For comparison purposes, a fresh-synthesized sample with the same composition has also been prepared using the commercial raw materials via the same method. X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical measurements have been carried out to characterize these samples. The electrochemical test result suggests that the re-synthesized sample delivers cycle performance and low rate capability which are comparable to those of the fresh-synthesized sample. This novel recycling technique can be of great value to the regeneration of a pure and marketable LiNixCoyMn(1âxây)O2 cathode material with low secondary pollution. Keywords: Spent lithium-ion battery, Cathode material recycling, Acid leaching, Purification, Co-precipitatio

Performance simulation method and state of health estimation for lithium-ion batteries based on aging-effect coupling model

Accurate simulation of characteristics performance and state of health (SOH) estimation for lithium-ion batteries are critical for battery management systems (BMS) in electric vehicles. Battery simplified electrochemical model (SEM) can achieve accurate estimation of battery terminal voltage with less computing resources. To ensure the applicability of life-cycle usage, degradation physics need to be involved in SEM models. This work conducts deep analysis on battery degradation physics and develops an aging-effect coupling model based on an existing improved single particle (ISP) model. Firstly, three mechanisms of solid electrolyte interface (SEI) film growth throughout life cycle are analyzed, and an SEI film growth model of lithium-ion battery is built coupled with the ISP model. Then, a series of identification conditions for individual cells are designed to non-destructively determine model parameters. Finally, battery aging experiment is designed to validate the battery performance simulation method and SOH estimation method. The validation results under different aging rates indicate that this method can accurately estimate characteristics performance and SOH for lithium-ion batteries during the whole life cycle

Structural evolution of layered oxide cathodes for spent Li–ion batteries: Degradation mechanism and repair strategy

Abstract Sustainable development has long been recognized as one of the most critical issues in today's energy and environment‐conscious society. It has never been more urgent to recycle and reuse the end‐of‐life cathode materials. Here, this work systematically investigates the structure‐critical degradation mechanism of polycrystalline LiNixCoyMn1−x−yO2 (NCM), combining experimental characterization and DFT simulations. Targeting the key degradation factors, a synergistic repair strategy based on deep mechanochemical activation and heat treatment was successfully proposed to direct regenerate the degraded NCM material. Studies indicate the induction and promotion of synergistic repair technique on the reconstruction of particle morphology, the recovery of the chemical composition and crystal structure, and the favorable transformation of the impurities phase in the failed materials. In particular, the synergistic repair process induces a gradient distribution of LiF and further enables partial fluorine doping into the NCM surface, forming abundant oxygen vacancies and increasing the content of highly reactive Ni2+. Benefiting from the comprehensive treatment for the multi‐scale and multi‐form degradation behaviors, the repaired material exhibits a capacity of 176.8 mA h g−1 at 0.1 C, which is comparable to the corresponding commercial material (172.8 mA h g−1). The satisfactory capacity of the recovered cathode proves that it is an effective direct renovating strategy

Purification and Characterization of Reclaimed Electrolytes from Spent Lithium-Ion Batteries

As an indispensable part of lithium-ion batteries (LIBs), closed-loop recycling, reusing the electrolyte from spent LIBs, has not yet been fulfilled experimentally. Herein, this paper presents a LIB electrolyte recycling approach which consists of supercritical CO₂ extraction, resin, and molecular sieve purification and components supplements. The resultant electrolyte exhibited a high ionic conductivity of 0.19 mS·cm^–1 at 20 °C, which was very close to a commercial electrolyte with the same composition. Moreover, the electrolyte was also electrochemically stable up to 5.4 V (vs Li/Li⁺) in the linear sweep voltammetry (LSV) measurement. The application potential of reclaimed electrolyte was demonstrated by Li/LiCoO₂ battery presenting the initial discharge capacity of 115 mAh·g^–1 with a capacity retention of 66% after 100 cycles at 0.2 C. This investigation is a crucial break for electrolyte recycling and opens a bright route toward realizing closed-loop LIB recycling