Identification of failure mechanisms in Ni rich cathodes relevant to the safety of a battery cell

识别与电池安全相关的富镍正极的失效机制

• 批准号: 2570149
• 金额: --
• 依托单位: University College London
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2570149
• 关键词: Identification; failure; mechanisms; Ni; rich

This project offers the opportunity to study the safety behaviour of Ni rich cathode materials at different SoH's and identify changes/weaknesses in the material with age. The primary focus is to analyse how safety characteristics evolve with the lifetime of the cathode material (focus on commercially available NMC 811) conducting abusive tests at different SoH's. Macro-, micro- and nano-CT measurements will inform in-situ microstructural changes within the battery, in situ XRD will elucidate structural changes in the cathode materials. Post-test analysis on the cathode materials - conducted using the facilities at JM (potentially supported by the University partner to fill in gaps) - will be undertaken to investigate compositional and structural changes at both the electrode's surface and the electrolyte. In tandem, electrochemical testing could be undertaken, alongside a portfolio of additional techniques including calorimetry, colorimetry thermal imaging and acoustic measurements to inform SoH.We will pursue parallel work streams on proprietary and model materials, the latter providing a platform for technique development and wider opportunities for publication without compromising IP, as well as alignment to the Faraday Institution projects, providing opportunities for wider correlative studies.Main Objectives:- Link micro/structural changes in the electrodes with changes in the electrochemical and ultimately the safety behaviour of the cells.- Understand the influence of physical product features on safety properties (e.g. primary and secondary particle size, density).- Develop a non-destructive test to determine the SoH of a cell.- Develop a strategy to further improve the safety performance of eLNO materials by using learnings to inform product development.Year 1: Development of a strategy and a detailed test plan for pouch cells including electrochemical characterisation (e.g EIS, GITT or PITT) and abusive safety tests. Abusive tests include, amongst others, accelerated rate calorimetry (ARC), nail penetration, overcharging and crush testing. Conduct first electrochemical abusive tests on pouch cells, post mortem X-ray imaging and tear down analysis. Establish links with Faraday Institution projects.Year 2: Development methods for correlated thermal/mechanical abuse tests with operando X-ray imaging. Systematic studies of NMC vs eLNO materials to determine safety and SoH characteristics, and development/implementation of accelerated stress tests. Beam time applications where appropriate, focussing on non-proprietary materials.Year 3: Correlation between chemical/morphological evolution in response to AST's and establish links to durability/failure. Establish platform capability for evaluation of safety performance for materials across time/length scales. Translation of synchrotron tools to lab environment.Year 4: Dissemination of findings, contribution to new standards/methodologies for cell safety. This project builds on, and is complementary to, an existing PhD project in collaboration with UCL (Drasti Patel is currently developing imaging and calorimetry techniques for JM battery materials): it tackles open questions relating to battery safety, but also strongly profits from the fundamental work which has already been conducted.

该项目提供了研究富镍阴极材料在不同SoH下的安全行为的机会，并确定材料随时间的变化/弱点。主要重点是分析安全特性如何随着阴极材料（重点是市售NMC 811）在不同SoH下进行滥用测试的寿命而演变。宏观、微观和纳米CT测量将告知电池内的原位微观结构变化，原位XRD将阐明阴极材料中的结构变化。对阴极材料的测试后分析-使用JM的设施进行（可能由大学合作伙伴提供支持以填补空白）-将进行调查电极表面和电解质的成分和结构变化。与此同时，可以进行电化学测试，以及其他技术组合，包括量热法，比色热成像和声学测量，以告知SoH。我们将在专有材料和模型材料上进行平行工作流，后者提供了一个技术开发平台和更广泛的出版机会，而不损害知识产权，并与法拉第研究所项目保持一致，为更广泛的相关研究提供机会。主要目标：-将电极中的微观/结构变化与电化学变化以及最终电池的安全行为联系起来。了解产品物理特性对安全性能的影响（例如，初级和次级粒度，密度）。开发一种非破坏性测试来确定细胞的SoH。制定战略，通过学习来指导产品开发，进一步提高eLNO材料的安全性能。第1年：制定战略和详细的软包电池测试计划，包括电化学表征（例如EIS，GITT或PITT）和滥用安全测试。滥用测试包括，除其他外，加速速率量热法（ARC），钉子渗透，过度充电和压碎测试。对软包电池进行首次电化学滥用测试，事后X射线成像和拆卸分析。建立与法拉第研究所项目的联系。第二年：开发与操作X射线成像相关的热/机械滥用测试方法。对NMC与eLNO材料进行系统研究，以确定安全性和SoH特性，并开发/实施加速应力测试。在适当的情况下，针对非专利材料进行射束时间应用。第3年：AST反应中化学/形态演变之间的相关性，并建立与耐久性/失效之间的联系。建立跨时间/长度尺度评价材料安全性能的平台能力。将同步加速器工具转化为实验室环境。第4年：传播研究结果，为细胞安全的新标准/方法做出贡献。该项目建立在与UCL合作的现有博士项目的基础上，并对该项目进行补充（Drasti Patel目前正在为JM电池材料开发成像和量热技术）：它解决了与电池安全有关的开放问题，但也从已经进行的基础工作中获益匪浅。