An overview of positive-electrode materials for advanced lithium-ion batteries

Positive-electrode materials for lithium and lithium-ion batteries are briefly reviewed in chronological order. Emphasis is given to lithium insertion materials and their background relating to the “birth” of lithium-ion battery. Current lithium-ion batteries consisting of LiCoO₂ and graphite are approaching a critical limit in energy densities, and new innovating materials are needed in order to continue the advance of lithium-ion batteries. In particular, the recent trends on material researches for advanced lithium-ion batteries, such as layered lithium manganese oxides, lithium transition metal phosphates, and lithium nickel manganese oxides with or without cobalt, are described. Trials on new applications of lithium insertion materials for high-power lithium-ion batteries as well as hybrid capacitors leading for 12 V lead-free accumulators are also highlighted.     

Review of lithium-ion battery state of charge estimation

The technology deployed for lithium-ion battery state of charge (SOC) estimation is an important part of the design of electric vehicle battery management systems. Accurate SOC estimation can forestall excessive charging and discharging of lithium-ion batteries, thereby improving discharge efficiency and extending cycle life. In this study, the key lithium-ion battery SOC estimation technologies are summarized. First, the research status of lithium-ion battery modeling is introduced. Second, the main technologies and difficulties in model parameter identification for lithium-ion batteries are discussed. Third, the development status and advantages and disadvantages of SOC estimation methods are summarized. Finally, the current research problems and prospects for development trends are summarized.     

薄膜锂离子电池负极材料的研究进展

全固态薄膜锂离子电池是锂离子电池的最新研究领域,其能量密度高、厚度薄、循环寿命长、可靠度高。薄膜化的负极材料是锂离子电池的重要组成部分,负极薄膜材料制备方法的研究取得了较大的进展,未来研究重点是低成本、低能耗、高综合电化学性能的负极薄膜材料以及可批量生产的薄膜制备技术。对薄膜化的硅负极材料、金属或合金薄膜材料、氧化物薄膜材料和复合薄膜材料近几年来的研究状况进行了综述,并对其发展前景进行了展望。     

Research progress on capacitive lithium-ion battery

锂离子电池具有高的能量密度,而超级电容器则以高功率密度和长循环寿命为突出优势。电容型锂离子电池是在锂离子电池的正极中加入部分电容炭材料,在不显著降低能量密度的情况下,大幅度改善锂离子电池的功率特性和循环寿命,从而实现电容与电池技术的融合。本文综述了国内外近年来在电容型锂离子电池领域的最新研究进展,介绍了主要的电容型锂离子电池体系及其性能特点,并对其未来发展方向进行了展望。     

Cycle-life testing of large-capacity lithium-ion cells in simulated satellite operation

We are conducting cycle-life testing of 10–100 Ah-class lithium-ion cells in a simulated satellite operation at the Japan Aerospace Exploration Agency (JAXA). This paper reviews the latest test results of these lithium-ion cells. Thus far, we have verified impressive life performance exceeding 30,000 cycles in a simulated low-earth-orbit (LEO) mode and 1800 cycles in a simulated geostationary-earth-orbit (GEO) mode for some of these cells. We optimized the thickness of the electrode layer to suppress cell-internal impedance and found that a lithium-ion cell with a thin electrode layer exhibited promising cycling performance in a simulated LEO operation. Since the electrode material is an important factor affecting the charge–discharge behavior of a lithium-ion cell, we also compared the cycling performance of lithium-ion cells with different cathode materials.     

Overview of research on thermal safety of lithium-ion batteries

随着锂离子电池在生活和工作中的普及,锂离子电池的安全事故逐年增加,锂离子电池的安全研究逐渐引起学术界的关注。研究锂离子电池的热安全性,可以有效分析锂离子电池发生起火和爆炸的内在原因,指导锂离子电池安全性研究的开展。本文介绍了锂离子电池工作过程中产热的来源和影响因素,以及锂离子电池热失控发生时的内部反应和反应对应的温度,并对电池热失控时的热特性参数进行了总结。     

Patent analysis of lithium ion power battery recycling technology

锂离子动力电池的回收是当前储能产业关注的焦点之一,为了解锂离子动力电池的回收现状,以CNABS和DWPI专利数据库中的检索结果为分析样本,对锂离子动力电池回收技术的专利申请量趋势、全球分布区域、国内外主要申请人、全球重点技术分布以及国内重点技术进行全面分析,结果表明,虽然锂离子动力电池回收技术是目前全球尤其是中国争相布局的产业对象,但目前各个企业的专利申请量均较小且技术布局零散,总体来说锂离子动力电池回收技术仍处于摸索阶段,产业前景不明,本文以期给锂离子动力电池回收技术未来的布局和发展提供一定的借鉴。     

Recent progress on evolution of safety performance of lithium-ion battery during aging process

安全性是制约锂离子电池规模应用的重要技术问题。锂离子电池的安全性能不仅仅与材料体系、电芯设计相关,还会随着使用过程而发生变化。锂离子电池安全性能在全生命周期内的演变规律需要重点展开研究,以保障电池在使用过程中的安全性。本文对锂离子电池全生命周期安全性演变问题的国内外研究进展进行了综述,分析了国内外关于电池安全性能在循环老化和储存老化两种工况下的演变规律的研究,总结了电池老化衰减机理与安全性能变化之间的关系,指出负极析锂是影响电池全生命周期安全性能的重要因素,最后对锂离子电池全生命周期安全性演变研究进行了展望。     

LiFePO4正极水性粘结剂的研究进展

磷酸铁锂（LiFePO4）具有安全性好、价格低廉以及环境友好等优点,是当前锂离子动力电池的主流正极材料。粘结剂是锂离子电池电极的重要非活性成分,其性能直接影响电池的电化学性能。本文综述了近年来不同水性粘结剂在LiFePO4正极材料中的研究进展,指出了现阶段存在的问题,并对水性粘结剂的应用前景进行了展望。     

The review of thermal management technology for large-scale lithium-ion battery energy storage system

大容量锂离子电池储能系统对完善传统电网和高效利用新能源都具有非常重要的作用。为了实现大容量锂离子电池储能系统的高倍率化、长寿命化以及高安全性,高性能电池热管理系统的研发刻不容缓。本文总结了温度对锂离子电池性能的影响规律,综述了空冷、液冷、热管冷却、相变冷却这4种典型热管理技术的研究概况,分析了热管理技术在锂离子电池储能系统中的应用与研究状况。随着锂离子电池储能系统工作倍率的提高,产热量随之增大,对热管理系统的要求也越来越高。下一步的研究工作应围绕空冷系统优化、基于新型冷却介质的液冷系统、经济型热管及多目标优化设计这4方面展开。     

Recent progress in rechargeable nickel/metal hydride and lithium-ion miniature rechargeable batteries

VARTA is searching for alternative battery solutions for memory back-up and bridging applications, and for this, it is developing nickel/metal hydride and lithium-ion button cells. Presented are the results on different sizes and forms of lithium-ion cells (621, 1216 and 2025) containing different electrode materials and shapes. Presently, the most favoured cathode material is lithiated manganese dioxide. The electrodes are made from both solid and porous materials and, together with an organic electrolyte, result in a cell system with a voltage level of approximately three. Included are results, both from these lithium-ion cells, and also from ones using the nickel/metal hydride system.     

基于加速寿命试验的锂离子电池可靠性分析方法

为了有效地提高锂离子电池寿命评估的准确性,延长储能系统在配电网中运行年限,文章提出了基于加速寿命试验的锂离子电池可靠性分析方法。综合考虑不同放电深度对锂离子电池寿命影响,建立了锂离子电池的寿命衰退模型;确定了荷电状态(SOC)与健康度(SOH)的关联特性关系;提出了基于逆幂率方程的储能系统加速寿命试验方法;基于情景分析法对锂离子电池的可靠性进行了分析。研究结果表明,文章所提出的试验方法能够准确地对不同运行状态下的锂离子电池储能系统进行可靠性评估,保证储能系统并网运行过程中的调控准确性。     

A comparison of methodologies for the non-invasive characterisation of commercial Li-ion cells

Lithium-ion cells currently power almost all electronic devices and power tools; they are a key enabling technology for electric vehicles and are increasingly considered to be the technology of choice for grid storage. In line with this increased applicability, there is also an increase in the development of new commercial lithium-ion cell technologies that incorporate innovative functional components (electrode material compositions and electrolyte formulations) and designs, leading to a diverse range of performance characteristics. The uniqueness of each technology in-turn gives rise to unique evolutions of cell performance as the cell degrades because of usage. Non-destructively measuring and subsequently tracking the evolution of lithium-ion cell characteristics is valuable for both industrial engineers and academic researchers. To proceed in this regard, stakeholders have often devised their own procedures for characterising lithium-ion cells, typically without considering unification, comparability or compatibility. This makes the comparison of technologies complicated. This comprehensive review for the first time has analysed and discusses the various international standards and regulations for the characterisation and electrical testing of lithium-ion cells, specifically for high-power automotive and grid applications.     

Safety test and evaluation method of lithium ion battery

对锂离子电池的机械滥用、热滥用和电滥用安全性测试与评价方法的原理进行了分析,对具有代表性的锂离子电池安全测试标准GB/T 31467.3/31485和SAE J2464/UN 38.3的相关试验方法进行了对比分析。应用X射线三维CT技术,测试了安全性试验前后锂离子电池内部结构的变化,对X射线三维CT应用于锂离子电池安全性测试分析的前景进行了展望。为锂离子电池安全失效模式分析指明了方向。     

A novel fast estimation and regroup method of retired lithium-ion battery cells

With the commercialization of the electric vehicles, the large-scale lithium-ion cells as the power of electric vehicles are to be retired. The second-use of retired cells is of great significance to improve the battery economy. A fast classification and regroup evaluation method of the retired lithium-ion cells are proposed in this paper to improve the classification efficiency of retired lithium-ion cells and adapt to the regroup under different conditions. The lithium-ion cells after being balanced in parallel are charged in series with a constant current. A support vector regression (SVR) model with the parameters optimized by the particle swarm optimization (PSO) algorithm is built for the fast capacity estimation and the error will not exceed 0.3%. Different cells regrouped means different performance. In order to improve the consistency of retired cells and satisfy different using conditions, a Weighted-K-means algorithm is proposed in this paper to regroup the cells with the known capacity and internal resistance. The classification method is evaluated by the voltage consistency of cells using different working conditions, which indicates capacity occupied a large proportion can meet the requirement of energy condition meanwhile keep a good consistency. But the resistance will dominate in algorithm under conditions which have requirement for instantaneous power.     

C,N co-doped Co3O4 hollow spheres prepared via hydrothermal reaction for improved electrochemical activity

Superior electrode materials play a key role on the electrochemical performance for the lithium-ion batteries and supercapacitors. The Co₃O₄-based materials are promising electrode materials due to their high specific capacity and energy density. However, the poor cycle performance limits their applications during the process of the commercialization for the lithium-ion batteries and supercapacitors. Because of the poor cycle stability, C, N co-doped Co₃O₄ hollow spheres are successfully prepared and used as electrode materials for the lithium-ion batteries and supercapacitors. Via the C, N co-doping process, the electronic conductivity is greatly improved. Moreover, the hollow structure could ensure the structural stability during the electrochemical process. As a result, the cycle performance and specific capacity are greatly improved when the C, N co-doped Co₃O₄ composites are used as electrode materials for the lithium-ion batteries and supercapacitors.     

Ionic liquids as electrolytes for Li-ion batteries—An overview of electrochemical studies

The paper reviews properties of room temperature ionic liquids (RTILs) as electrolytes for lithium and lithium-ion batteries. It has been shown that the formation of the solid electrolyte interface (SEI) on the anode surface is critical to the correct operation of secondary lithium-ion batteries, including those working with ionic liquids as electrolytes. The SEI layer may be formed by electrochemical transformation of (i) a molecular additive, (ii) RTIL cations or (iii) RTIL anions. Such properties of RTIL electrolytes as viscosity, conductivity, vapour pressure and lithium-ion transport numbers are also discussed from the point of view of their influence on battery performance.     

Investigation of aging mechanisms of high power Li-ion cells used for hybrid electric vehicles

High power lithium-ion batteries need to exhibit long service life to meet targets of automotive applications. This article describes the deep investigation of the so-called VL6P cells, high power lithium-ion cells mass produced by Johnson Controls - Saft (JC-S), in order to understand the root causes of their aging. Cells aged by calendar and cycle life are investigated here compared to fresh cells. Among the results of the different analyses, the most significant is that more active lithium is detected in negative electrode after aging. This tends to indicate that effect of aging is due to increase of positive electrode limitation. Results of this investigation will allow JC-S to continue to improve life of the lithium-ion cells.     

Three-dimensional layered electrochemical-thermal model for a lithium-ion pouch cell

Performance of lithium-ion pouch cell cannot be evaluated only by its external characteristics, such as the surface temperature and potential, as the internal electrochemical and thermal properties of the cell can significantly affect its performance. However, it is difficult to observe the internal thermal and electrochemical characteristics by means of experiment. Within this study a layered three-dimensional electrochemical-thermal coupled model of a lithium-ion pouch cell is proposed, then it is verified by experimental method at several discharge rates. According to this model, the spatial distribution of temperature field and heat generation rate are analyzed at four discharge rates, a fitted surface equation is presented for this battery to roughly predict the heat generation rate according to the discharge rate and depth of discharge. Afterward, several representative electrochemical properties (electric potential, electrolyte concentration, electrode current density, and mass transfer process) are investigated from the spatial perspective, which reveals the transfer process of lithium-ion and current clearly inside the battery. It is also concluded that there exists a gradient both at the plane and thickness of the electrode, and the gradient in the thickness direction is larger than that in the plane. A large gradient in temperature, lithium-ion concentration, electrode potential and current density distribution are located at the connection between tabs and electrodes.     

Autonomous health management design for lithium-ion battery in middle and high orbit satellites

针对中高轨卫星蓄电池组在轨管理问题,在分析某型号在轨使用需求和锂离子蓄电池特性的基础上,提出了锂离子蓄电池在轨自主健康管理系统的设计,并在某MEO轨道卫星上进行了验证,通过在轨数据分析,验证了所设计系统的有效性,为后续型号锂离子蓄电池组在轨自主管理提供经验。