Mar 2nd, 2009, 21:01
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【注意】“磷酸锂铁”电池真的是比亚迪独门秘笈吗？
http://zh.wikipedia.org/w/index.php?...ariant=zh-hans 磷酸锂铁 维基百科，自由的百科全书 跳转到: 导航, 搜索 目录 [隐藏] * 1 磷酸锂铁(LiMPO4; LFP) o 1.1 LiMPO4简介 o 1.2 为LiFePO4正名 o 1.3 LFP的发现 o 1.4 LFP运作的原理 + 1.4.1 LFP的物理化学性质 o 1.5 LFP在产业上的应用 + 1.5.1 LFP上下游产业高速发展 + 1.5.2 GE, Google, 巴菲特与欧洲大厂纷纷宣布进入LFP产业 + 1.5.3 LFP材料特性与产业发展关联 o 1.6 LFP的专利战争 + 1.6.1 LiMPO4的欧洲专利遭到判决撤销 + 1.6.2 昂贵的和解:NTT为LFP材料向德州大学支付3000万美金和解金 o 1.7 LFP的再改良 + 1.7.1 金属位置的取代 + 1.7.2 LFP制备方式改良与工业化 o 1.8 参考文献 [编辑] 磷酸锂铁(LiMPO4; LFP) [编辑] LiMPO4简介 磷酸锂铁（分子式LiMPO4，Lithium Iron Phosphate ，又称磷酸铁锂、锂铁磷，简称LFP），是一种锂离子电池(可另外参见http://zh.wikipedia.org/wiki/%E9%94%...94%B5%E6%B1%A0) 的正极材料，也称为锂铁磷电池，特色是不含钴等贵重元素，原料价格低且磷、锂、铁存在于地球的资源含量丰富，不会有供料问题。其工作电压适中（3.2V）、电容量大（170mAh/g）、高放电功率、可快速充电且循环寿命长，在高温与高热环境下的稳定性高。这个看似不起眼却引发锂电池革命的新材料，为橄榄石结构分类中的一种，矿物学中的学名称为（ triphyllite ），是从希腊字的Tri以及 fylon两个字根而来，在矿石中的颜色可为灰色，红麻灰色，棕色或黑色，相关的矿物资料可参考网站[1]。 [编辑] 为LiFePO4正名 LiFePO4正确的化学式应该是LiMPO4, 物理结构则为橄榄石结构, 而其中的M可以是任何金属, 包括Fe,CO,Mn,Ti等等, 由于最早将LiMPO4商业化的公司所制造的材料是C/LiFePO4, 因此大家就这么习惯地把Lithium Iron Phosphate 其中的一种材料LiFePO4当成是磷酸铁锂。然而从橄榄石结构的化合物而言, 可以用在锂离子电池的正极材料并非只有LiMPO4一种, 据目前所知, 与LiMPO4相同皆为橄榄石结构的Lithium Iron Phosphate 正极材料还有AyMPO4、Li1-xMFePO4、LiFePO4･MO等三种与LiMPO4不同的橄榄石化合物(均可简称为LFP)。 [编辑] LFP的发现 自1996年日本的NTT首次揭露AyMPO4(A为碱金属，M为CoFe两者之组合:LiFeCOPO4)的橄榄石结构的锂电池正极材料之后, 1997年美国德克萨斯州立大学John. B. Goodenough等研究群，也接着报导了LiFePO4的可逆性地迁入脱出锂的特性[1]，美国与日本不约而同地发表橄榄石结构(LiMPO4), 使得该材料受到了极大的重视，并引起广泛的研究和迅速的发展。与传统的锂离子二次电池正极材料，尖晶石结构的LiMn2O4和层状结构的LiCoO2相比，LiMPO4 的原物料来源更广泛、价格更低廉且无环境污染。 [编辑] LFP运作的原理 LFP橄榄石结构的锂电池正极材料，已经有多家上游专业材料厂展开量产，预料将彻底大幅扩张锂电池的应用领域，将锂电池带到扩展至电动自行车、油电混合车与电动车的新境界；日本东京工业大学由山田淳夫教授所领导的一个研究小组，在2008年8月11日出版的《自然•材料》报告说，磷酸锂铁离子电池将会被用作清洁环保的电动汽车的动力装置，其前景被普遍看好。由山田淳夫教授所领导的东京工业大学与东北大学的联合研究人员，使用中子射线照射磷酸铁，然后分析中子和物质之间的相互作用来研究锂离子在磷酸铁中的运动状态。研究人员的结论是，在磷酸锂铁中，锂离子按照一定方向笔直地扩散开去，这与锂离子在现有的钴等电极材料中的运动方式不同。这样的结论与原先推估的理论完全一致，使用中子绕射分析的结果，更加证实了磷酸锂铁（LFP）可以确保锂电池的大电流输出输入的安全性。 [编辑] LFP的物理化学性质 磷酸锂铁化学分子式的表示法为：LiMPO4，其中锂为正一价；中心金属铁为正二价；磷酸根为负三价，中心金属铁与周围的六个氧形成以铁为中心共角的八面体FeO6，而磷酸根中的磷与四个氧原子形成以磷为中心共边的四面体 PO4，借由铁的FeO6八面体和磷的PO4四面体所构成的空间骨架，共同交替形成Z字型的链状结构，而锂离子则占据共边的空间骨架中所构成的八面体位置，晶格中FeO6通过 bc 面的共用角连结起来，LiO6则形成沿着b轴方向的共边长链，一个FeO6八面体与两个LiO6八面体和一个PO4四面体共边，而PO4四面体则与一个 FeO6八面体和两个LiO6八面体共边。在结晶学的对称分类上属于斜方晶系Orthorhombic中的Pmnb空间群，单位晶格常数为 a=6.008Å，b=10.334Å，c=4.693Å，单位晶格的体积为291.4m3。由于结构中的磷酸基对整个材料的框架具有稳定的作用，使得材料本身具有良好的热稳定性和循环性能。 LiMPO4中的锂离子不同于传统的正极材料LiMn2O4和LiCoO2，其具有一维方向的可移动性，在充放电过程中可以可逆的脱出和迁入并伴随着中心金属铁的氧化与还原。而LiMPO4 的理论电容量为 170mAh/g，并且拥有平稳的电压平台 3.45V。其锂离子迁入脱出的反应如下所式： LiFe(II)PO4 ↔ Fe(III)PO4 + Li+ + e- (1) 锂离子脱出后，生成相似结构的 FePO4，但空间群也为Pmnb，单位晶格常数为 a=5.792Å，b=9.821Å，c=4.788Å，单位晶格的体积为272.4m3，锂离子脱出后，晶格的体积减少，这一点与锂的氧化物相似。而LiMPO4中的FeO6八面体共顶点，因为被PO43-四面体的氧原子分隔，无法形成连续的FeO6网路结构，从而降低了电子传导性。另一方面，晶体中的氧原子接近于六方最密堆积的方式排列，因此对锂离子仅提供有限的通道，使得室温下锂离子在结构中的迁移速率很小。在充电的过程中，锂离子和相应的电子由结构中脱出，而在结构中形成新的FePO4相，并形成相界面。在放电过程中，锂离子和相应的电子迁入结构中，并在 FePO4相外面形成新的LiMPO4相。因此对于球形的正极材料的颗粒，不论是迁入还是脱出，锂离子都要经历一个由外到内或者是由内到外的结构相的转换程[1] [2]。 材料在充放电过程中存在一个决定步骤，也就是产生 LixFePO4 / Li1-xFePO4 两相界面。随着锂的不断迁入脱出，界面面积减小，当到达临界表面积后，生成的FePO4电子和离子导电率均低，成为两相结构。因此，位于粒子中心的LiMPO4得不到充分利用，特别是在大电流的条件下。 若不考虑电子导电性的限制，锂离子在橄榄石结构中的迁移是通过一维通道进行的，并且锂离子的扩散系数高，并且LiMPO4经过多次充放电，橄榄石结构依然稳定，铁原子依然处于八面体位置，可以做为循环性能优良的正极材料 [3]。在充电过程中，铁原子位于八面体位置，均处于高自旋(high spin)状态。 [编辑] LFP在产业上的应用 首先采用这种锂电池材料的油电混合车是GM的CHEVROLET Volt，这部插电式油电混合车（PHEV）将在2010年正式在市面上销售，它突出的省油性能与驾控的舒适，使得它尚未销售，目前已经有将近四万名美国民众抢先订购；Volt每次充电后的续航力为60公里，若遇到长途旅程，车上则搭载了小型汽油引擎来为电池充电，让Volt能跑得更远。GM相信这款 PHEV能拥有150mpg的油耗表现。在日本与中国大陆则是有更多的锂电池厂纷纷投入这种新型动力锂电池的生产，目标市场就是电动自行车与电动公交车。 [编辑] LFP上下游产业高速发展 目前LFP最上游的化合物专利被三家专业材料公司所掌握，分别是A123的Li1-xMFePO4、Phostech的LiMPO4以及 Aleees的LiFePO4･MO，同时也已经发展出十分成熟的量产技术，其中最大的产能已可达月产250吨。A123的Li1-xMFePO4主要的特征是奈米级的LFP，借由奈米物理性质的改变以及在正极材料当中添加了贵金属，并辅佐特殊材质的石墨为负极，使得原本导电能力较差的LFP，可以成为商业化应用的产品；Phostech的LiMPO4主要特征是借由适当Mn, Ni , Ti的参杂, 并且在LFP外层借由适当的碳涂布, 来增加电容量与导电性；Aleees的LiFePO4･MO的主要特征是以氧为共价键, 借由前驱物在高过饱和度与激烈机械搅拌力的状态下，造成金属氧化物与磷化物发生激动起晶之作用，从而产生金属氧化物共晶LFP的晶核，使得原本难以控制的二价铁与晶相成长，得到了稳定的控制。 这些上游材料的突破与快速发展，引起了锂电池厂与汽车业者的注意，并且带动了锂电池与油电混合车的兴盛之路；LFP电池和一般锂电池同为绿色环保电池，但两者最大不同点是完全没有过热或爆炸等安全性顾虑，再加上电池循环寿命约是锂电池的4~5倍，高于锂电池8~10倍高放电功率（可瞬间产生大电流），加上同样能量密度下整体重量，约较锂电池减少30~50%，包括美国国防部的油电混合坦克车与悍马车（近战隐匿）、通用汽车、福特汽车、丰田汽车等业者皆高度重视LFP电池发展。A123甚至因此获得了高达数千万美金的政府补助，目的就是要扶植美国的锂电池业者，利用油电混合车的发展机遇，一举击败遥遥领先的日本汽车业者。 从各国发展来看，美国汽车产业界预估到2010年时全美的油电混合车将超过400万台。美国通用汽车为了打破日系车厂独霸局面，决定大幅朝向设计生产“可大规模生产的电动车”，因为现在许多美国消费者早已不堪高油价压力，通用认为未来汽车必须能够使用各种能源，其中电动车将成为关键。因此，GM在 07年北美国际车展公开展示插电式油电混合动力车（Plug-in Hybrid Electric Vehicle，PHEV）的概念车“Chevrolet Volt Concept”，配合GM全新开发油电混合动力系统（E-FLEX），只要接上一般家用电源便可为该车的磷酸锂铁电池充电。如果Volt Concept达到量产阶段，每台车每年可减少500加仑（1,900公升）汽油消耗，也可以减少4,400公斤二氧化碳产出。 [编辑] GE, Google, 巴菲特与欧洲大厂纷纷宣布进入LFP产业 面对如此锐不可挡的发展，一些工业银行、创投基金与投资公司早就把目光放在上游材料公司的布局上，除了上述三家公司之外，在美国除了A123之外，ActaCell Inc.刚刚从谷歌(Google)旗下Google.org、应用材料(AMAT)风险投资部门和其他一些风险投资公司得到了580万美元资助。 ActaCell的主要业务就是将德州大学学者的成果推向市场，这个学者就是长期以发展尖晶石结构以及超导材料为主的Arumugam Manthiram教授，他早期在UT担任研究助理，之后逐渐升为教授，这几年他发现了在磷酸铁锂（LFP）当中，加入了昂贵的导电高分子之后，可以在实验室做出克电容量166Ah/g的磷酸铁锂（LFP），并且采用微波法加速磷酸铁锂（LFP）陶瓷粉末快速成相。至於是否因为加入了导电高分子，就可以突破A123、Aleees、Phostech等三家重量级业者在磷酸铁锂（LFP）的主要专利与次级改良专利布局，只能等到事态更加明朗方能评论。 不过下游的应用业者的脚步可是一点都没有因此而缓慢下来，GE(www.ge.com)在全球首页公布GE一连串大规模应用LFP电池的计划, GE打算从电动火车头, 飞机, 电动车, 太阳能电网, 风力发电电网等大型机电应用, 扩大GE的营收; 在欧洲，BOSCH就在2008年公开承诺将持续增加电动与油电车辆科技的开发，尽管欧洲有人觉得这两项科技可能使用的人会非常的有限，但是根据油价高涨的状态，传统往复式引擎或许还有20年的优势，但是终究汽车的动力模式会转型。BOSCH拥有傲人的汽车科技研发历史，由于不会向TOYOTA购买油电混合科技，所以整体研发都是BOSCH自己进行，因此像是防锁死煞车还有TCS循迹控制系统，也将会重新设计与油电混合电脑程式组合在一起，首次经由 BOSCH递交给VW Touareg与PORSCHE Cayenne的油电车将会于2010年上市。 BOSCH原先打算维持自己在燃油科技的领先地位，就如同已经在汽车安全行业的优势，面对电力的全新汽车能源领域，BOSCH认为有必要深入纯电动动力的领域，因为那是一项未来真实世界都会普遍使用的科技，其中电池是电动引擎动力的关键性科技，BOSCH与南韩SAMSUNG合作以4亿美金开发锂电池并且进行量产化，虽然距离成熟的时间预估还要四到五年，不过BOSCH无论如何都会继续投资，以保持汽车科技上面的领先地位。 另外欧洲一家汽车零组件的一级供应商大厂Continental也宣布磷酸铁锂（LFP）的合作伙伴有A123 Systems 及 Johnson Controls-Saft。而Continental 将会供给电池组给Mercedes Benz，关于 Continental 提供给Bosch案子，可能会考虑自己做或外购如向A123购买，为了供应链的安全，他们也买了日本小型电池厂Enax的股份，但这家公司只能做小伏特数的产品。 在日本的GS YUASA也不遑多让，之后就立即公布了将自主开发的碳负载型磷酸铁锂（LFP）应用于大型电池单元正极的结果。使用外形尺寸为 115mm×47mm×170mm的方形“LIM40”工业电池单元实施的试验表明，即使以400A的大电流放电，容量也几乎不会降低。而未使用负载碳的该公司原产品，其400A放电时的容量比40A放电时减半。另外此次的试制品足可在-20℃的低温下使用。 在中国两家重量级的锂电池大厂：天津力神与比克（BAK），则也宣布了年产2000万颗磷酸铁锂（LFP）的专用电池厂，分别将在2008年年底与 2009年初完成建厂，总投资金额高达6亿美金，至於上游的合作对象，则尚未见诸于报端，据一般的猜测，可能是三家磷酸铁锂（LFP）业者当中，其中一家生产工厂位于亚洲的业者。 但是在中国最受瞩目的LFP业者还是比亚迪(BYD)电池与电动车公司, 波克夏•海瑟威公司(Berkshire Hathaway Inc.)（纽约证券交易所：BRKA和BRKB）旗下的子公司中美能源控股公司(MidAmerican Energy Holdings Company)在2008年10月宣布，认购2.25亿股比亚迪股份有限公司(1211.hk)的股份，约占10%的股份比例，投资约2.3亿美元。所谓波克夏•海瑟威公司的此一投资案之所以引起瞩目, 原因就是该公司主席兼执行长华伦•巴菲特先生享有股神的称号。 如此一来在2010年以前，欧洲、美国与亚洲的磷酸铁锂（LFP）业者的联盟版图看来已经大致底定；各家电池工艺的高低，也随着磷酸铁锂（LFP）材料的高安全性与稳定性，显得不再是那么重要；唯一决定胜负的恐怕还是市场价格，根据一般的估计，在2010年以前哪一组联盟能够把磷酸铁锂（LFP）动力电池的价格下降到每瓦时0.35美金，谁就能牵动油电混合车与锂电池自行车的高速发展、谁就会是最后的赢家。 [编辑] LFP材料特性与产业发展关联 不过真正决战点恐怕还是取决于油电混合车的市场，LFP材料在锂电池被重视的主要原因，根本原因其实仍然是LFP安全的橄榄石结构，这样的结构有别于其他锂电池的层状与尖金石结构的锂钴或锂锰系列的电池正极材料；橄榄石结构的LFP，由于结构上与氧(O2)的键结很强，因此在锂电池发生短路时，不会因为短路而产生爆炸；这样的条件或许在其他移动式IT产品不是最重要的（注：因为即便是笔记本电脑与手机爆炸事件层出不穷，日本大厂回收动辄高达数十万台笔记本电脑，但是大部分的消费者仍然选择高容量却容易爆炸的锂钴电池），但是在汽车上的锂电池应用就不是这么回事了。 根据美国AABC的统计，依照笔记本与手机锂电池爆炸的机率推算，如果将含有钴系或锰系的电池应用在油电混合车(PHEV,HEV BEV), 那么每七万台汽车就会有一台发生爆炸事件，这样的统计与研究震惊了汽车业者，汽车业者考虑的第一优先的问题是安全而不是容量，原因无他，对于汽车业者而言，汽车回收recall的成本高过笔记本电脑的成本数以万倍计算，因此他们必须设法在安全与续航力之间做出一个取舍。 从LFP的材料结构而言，LFP的电容量虽然比其他的锂电池容量少了25%，不过比起镍氢电池而言效益却提升了70%，安全的特性加上容量的提升使得汽车业者仿佛看到了救世主一般，他们从LFP的身上看到了安全与续航力的平衡点。因此油电混合车也因为这样成为兵家必争之地。 根据统计，HEV、PHEV及BEV在2008年在全世界至少会有7亿美元的市场，在2012年则将增长到至少50亿美元。而2008年到2015 年之间，全球油电车销售量预计将成长12%，在2012年美国的油电车销售量将会突破100万辆大关。在日本方面2008年到2011年之间，油电车产量将增加6.6%。整体而言2010年到2015年之间，油电车电池市场的成长率将达到10.4%，有关油电车的零件市场将成长17.4%。 除了小客车的市场之外巴士制造商的目光也看到了LFP的快速发展，BAE的HybriDrive猎户座七混合电动客车也宣布采用LFP大约 180KW的电池组。电力业者也快速采用LFP的电池，例如美国的AES公司就仰赖LFP电池发展出多兆瓦的电池系统有能力执行电网的配套服务，包括备用的备用容量以及频率调节服务。 [编辑] LFP的专利战争 [编辑] LiMPO4的欧洲专利遭到判决撤销 面对如此强劲的发展，十多年前发现LFP橄榄石其中一种化合物的德州大学教授Goodenough大概想都没想到，一个以磷酸(通常用于化肥)铁锂离子组合成的微米材料，竟然快速地改变了许多的重要产业发展；当然也因此专利纷争不断，A123, Aleees, Valence等三家公司并不认为他们的化合物专利有任何的侵权问题，但是他们的对手美国德州大学与加拿大自来水公司Hydro-Quebec（超牛的公司，俺上博士的时候去过该公司做实验）当然不作如是想。 在2005年和2006年的美国专利诉讼中，美国德州大学与Hydro-Quebec声称凡是使用LiFePO4正极材料的电池都侵犯了他们的美国专利号5910382和美国专利号6514640，并涉及到某些锂离子电池中所使用的电极材料。该'382和'640专利，声称包括电池正极材料有一个特别的晶体结构和化学公式。但是显然对于A123与Aleees而言，他们都认为他们的正极材料有不同的晶体结构和化学公式。因此不存在专利侵权的问题。 2006年4月7日，一项在美国地方法院马萨诸塞州寻求宣告性裁决，拥有不同的晶体结构和化学公式的LFP橄榄石材料，并不侵犯这些专利。经过这些相关的诉讼，使得美国德州大学不得不修订382专利的索赔范围，使他们的专利更加狭窄；这些拥有不同晶体结构的LFP公司趁胜追击，2008年4月15 日，美国PTO发出了修订索赔和两项新的索赔要求的复审证书。目前复查640专利工作仍在进行中，这场LFP材料专利大战的结论尚未宣告烟消云散。 2008年12月9日欧洲专利局（EPO）异议处的裁决撤销了授予德州大学（University of Texas）的有关LiMPO4的欧洲专利, 也裁决撤销了德州大学Goodenough等人的欧洲专利，该项判决也就是等于消除了下一代电动汽车电池的关键材料在欧洲侵权的任何风险。 LiMPO4专利遭到撤销的原因是该专利缺乏新颖性。根据裁决，原授予德州大学的0904607号欧洲专利现已被欧洲专利局完全撤销。德州大学可对这份专利撤销决议提起上诉。也就是说德州大学根据这项欧洲专利提出专利侵权索赔的任何可能性都已烟消云散。 有关LFP化学式与晶体结构的专利大战还在进行当中，却已经把许多知名的锂电池大厂拖下了水，包括松下电器、三星汽车的能源供应公司(AESC)、 Johnson Controls-SAFT、东芝、日立、Aleees、Enerdel、Altairnano、三井造船、LG、Johnson controls、AESC、Valence、SAFT、ABB、E-one Moli全部都在LFP的战役中寻找胜出之路，包括美国政府在内也砸下5500万美金资助LFP的发展。 [编辑] 昂贵的和解:NTT为LFP材料向德州大学支付3000万美金和解金 不过尽管目前这种新一代的材料尽管已经确定会是电动自行车、油电混合车与电动车的重要动力装置，但是事实上并无人理会气候变迁与二氧化碳的议题，人们还是得先考虑商业利益，因此在商业化的路途当中，首要面临的障碍就是专利的壁垒，许多较早进入此一领域的企业早已完成专利的部署，导致后进者会不经意地走入专利的陷阱当中。第一个被迫支付高额和解金的公司就是日本国营的NTT公司。 2008年10月日本公司NTT宣布与美国德州大学(UT)在日本最高民事法庭外达成和解, NTT要支付德州大学(UT)高达3000万美金的和解金, 尽管UT同意NTT并未发生过窃取德州大学营业秘密的说词, 但是NTT却被迫将所拥有之磷酸锂铁电池材料专利专属授权给德州大学(UT); NTT所拥有的专利其实也是LFP橄榄石结构的一种, NTT的化学式是AyMPO4 (A为碱金属，M为CoFe两者之组合), 这个组合就是比亚迪BYD(该公司因为获得巴菲特投资LFP电动车而声名大噪)目前正在使用的LFP材料完全相同, NTT的AyMPO4从专利的角度来说, 其实与德州大学的LiMPO4并不相同, 甚至AyMPO4的容量密度还要高于LiMPO4, 然而却因为NTT的工程师冈田重人涉嫌窃取德州大学的营业秘密, 使得NTT不得不将AyMPO4被迫让出给德州大学, 失去了在此一重要材料发展的契机。一颗颗灰色不起眼的LFP材料(Lithium Iron Phosphate )却能引发欧美厂商的战争，实在令人始料未及。 [编辑] LFP的再改良 目前LFP材料本身较差的导电性和较低的锂离子扩散系数一直是阻碍其实用化的最主要原因，因而促使国内外学者在提高LiMPO4的导电能力的方面展开了研究。但由于其极低的电子导电率（10-10~10-9 S/cm）是限制其实际应用的最主要因素。A123已经能够透过包覆、取代、制备成奈米级材料等改质的方法来克服此一缺点。加入导电物质为了提高脱锂后的FePO4的电子导电性，可以在LiMPO4 粉末间引入分散性能良好的导电剂，例如碳黑或碳 [5]，可以明显提高粒子间的导电性能，使得LiMPO4 的利用效率提高，可逆电容量可以达到理论值的95%，即使是在5C的大电流充放电条件下循环性能表现亦十分良好 [6] 。 另外，利用无机氧化物进行表面包覆的方法亦是提高结构稳定性增加材料导电度的手段之一，在传统的LiCoO2 中包覆后的循环性能有了明显的提高，并且包覆层可以防止钴的溶解，抑制电容量的衰退，同样地，将LiMPO4 晶粒进行无机物(如ZnO [7] 或 ZrO2[8]) 的表面包覆，除了可以改善循环寿命上的表现，亦可增进电容量与大电流放电时的表现。 由于加入导电性碳能够提高 LiMPO4 的利用效率，而像是日本三井造船与Aleees则发表加入其他具有导电性能的金属如铜或银的粒子也可以达到同样的效果[9]，加入1%重量百分比的金属后，可逆容量可达140mAh/g，而且大电流放电性能都比较理想。 [编辑] 金属位置的取代 为了提高LiMPO4 的利用效率，也可以进行铁原子位置或锂原子位置的取代，A123与VALENCE曾经发表以镁、钛、锰、锆、锌进行取代；以锌的取代为例，由于锌的离子半径与铁的离子半径相近，因此以锌原子取代之后，LiMPO4 的结晶性有一定程度的提高 [10]。而借由循环伏安法的量测可以看出，经由金属原子取代之后的LiFe1-xMxPO4 ，锂离子迁入和脱出的可逆性可以得到提升，并且也抑制了二价铁离子在脱出锂后变为三价铁时，晶格体积变小后产生往返路径变化的影响。 [编辑] LFP制备方式改良与工业化 与锂金属氧化物一样，LiMPO4 可以采用的合成制作方式大约分为以下的方法： 1. 固相合成法 2. 乳化干燥法 3. 溶胶凝胶法 4. 溶液共沉法 5. 气相沉积法 6. 电化学合成法 7. 电子束辐照合成法 8. 微波法 9. 水热法 10. 超音波裂解法 11. 喷雾裂解法…等，并且依据工艺的不同来达到不同的结果，例如，乳化干燥法是先将煤油与乳化剂混合，然后与锂盐、铁盐的水溶液混合，利用该法可以控制碳粒子的大小在奈米范围[11]，而采用水热法可以得到晶形良好的LiMPO4 ，但是为了加入导电碳，在水溶液中加入聚乙二醇，再借由热处理过程转变为碳[12]，而气相沉积法可以用来制备薄膜型态的LiMPO4[13]。 [编辑] 参考文献 [1] J. Electrochem. Soc , 1997, 144, 1609-1613. [2] J. Electrochem. Soc, 2004, 151, A1517-A1529. [3] J. Phys. Chem. B 2004, 108, 7046-7051. [4] J. Electrochem. Soc, 2005, 152, A191-A196. [5] J. Power Sources, 2004, 137, 93–99. [6] J. Power Sources, 2006, 153, 274–280. [7] J. Electrochem. Soc, 2008, 155, A211-A216.. [8] Electrochem Commun, 2008, 10, 165–169. [9] Electrochem and Solid-State Lett, 2002, 5, A47-A50. [10] Materials Letters, 2005, 59, 2361–2365. [11] J. Power Sources, 2004, 133, 272–276. [12] Solid State Ionics, 2004, 175, 287-290. [13] Materials Science and Engineering: B, 2007,142, 86-92. 此帖于 Mar 2nd, 2009 21:23 被 ryxtony 编辑。 |
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Lithium iron phosphate From Wikipedia, the free encyclopedia Jump to: navigation, search This article needs additional citations for verification. Please help improve this article by adding reliable references. Unsourced material may be challenged and removed. (August 2008) Lithium iron phosphate (LiFePO4) is a compound used in lithium iron phosphate batteries[1] (related to Li-Ion batteries). It is targeted for use in power tools, electric vehicles and some laptops. Most lithium batteries (Li-ion) used in 3C (computer, communication, consumer electronics) products are mostly lithium cobalt oxide (LiCoO2) batteries. Other lithium batteries include lithium manganese oxide (LiMn2O4), lithium nickel oxide (LiNiO2), and lithium iron phosphate (LFP). The cathodes of lithium batteries are made with the above materials, and the anodes are generally made of carbon. Avoiding the lithium cobalt oxide cathode leads to a number of advantages. LiCoO2 is one of the more expensive components of traditional li-ion batteries, giving LFP batteries the potential to ultimately become significantly cheaper to produce. LiCoO2 is also toxic, while lithium iron phosphate is not. LiCoO2 also can lead to problems with runaway overheating and outgassing, making batteries that use it more susceptible to fire than LFP batteries. This advantage means that LFP batteries don't need as intense charge monitoring as traditional li-ion. Lastly, LFP batteries tend to have superior power density in comparison to traditional li-ion. Contents [hide] * 1 LiFePO4 introduction * 2 Nomenclature of LiFePO4 * 3 Discovery of LFP * 4 Theory behind LFP * 5 The Physical and Chemical Properties of LFP * 6 Rapid Development of the LFT Upstream and Downstream Industries * 7 Properties of LFP and Development of the Industry * 8 LFP Patent Wars * 9 An Expensive Settlement: NTT Paid 30 Million US Dollars to UT as Settlement of the LFP Lawsuit * 10 Improvement of LFP * 11 Metal Substitution * 12 Improvement of LFP Synthesis Processes * 13 Example application * 14 References * 15 See also [edit] LiFePO4 introduction Lithium iron phosphate (molecular formula is LiFePO4, also known as LFP), is used as cathode material for lithium-ion batteries (also called lithium iron phosphate battery). Its characteristic does not include noble elements such as cobalt, the price of raw material is lower and both phosphorus and iron are abundant on Earth which lowers raw material availability issues. Batteries using this cathode material have a moderate operating voltage (3.3V), high energy storage capacity (170mAh/g), high discharge power, fast charging and long cycle life, and its stability is also high when placed under high temperatures or in a high thermal environment. This seemingly ordinary but, in fact, revolutionary and novel cathode material for lithium-ion batteries belongs to the olivine group. The etymology of its mineral name – triphyllite - is from the Greek “tri” and “fylon”. This mineral is gray, red-grey, brown, or black. Detailed information about this mineral can be found on the website [1]. [edit] Nomenclature of LiFePO4 The correct chemical formula of LiFePO4 is LiMPO4. LiFePO4 has an olivine crystal structure. The M of the chemical formula refers to any metal, including Fe, Co, Mn, Ti, etc. The first commercial LiMPO4 was C/LiFePO4 and therefore, people refer to the whole group of LiMPO4 as lithium iron phosphate, LiFePO4. However, more than one olivine compounds, in addition to LiMPO4, may be used as the cathode material of lithium iron phosphate. Such olivine compounds as AyMPO4, Li1-xMFePO4, and LiFePO4-zM have the same crystal structures as LiMPO4 and may be used as the cathode material of lithium ion batteries. (All may be referred to as “LFP”.) [edit] Discovery of LFP LiFePO4 was first reported by Akshaya Padhi of John Goodenough's group at University of Texas at Austin in 1996[2] as an excellent candidate for the cathode of rechargeable lithium battery that is inexpensive, nontoxic, and environmentally benign. The reversible extraction of lithium from LiFePO4 and insertion of lithium into FePO4 was demonstrated. The subsequent R&D in the electrochemical energy storage all over the globe has been geared to overcoming the processing and engineering challenges that has led to current use LiFePO4 in rechargeable lithium batteries. [edit] Theory behind LFP This lithium battery’s cathode material of olivine composition is already being mass produced by several up source professional material manufacturers. It is expected to widely expand the applications in the field of lithium batteries, and take it to the new fields such as electric bicycles, gas-electric hybrid vehicles and automation vehicles; In Tokyo Japan, a research group led by Professor Atsuo Yamada of Tokyo University of Technology, published a report on August 11 2008 issue of “natual materials” which included the following statement: the lithium-ion iron phosphate battery will be used as the power source for environmental-friendly electric cars, which have great future prospects. The Tokyo University of Technology and North East University research group is led by Professor Atsuo Yamada. The group uses neutron irradiation phosphate iron, and then analyzes the interaction between neutron and materials to study the motion status of lithium-ion in iron phosphate. The researchers concluded that in the lithium iron phosphate, lithium-ion extended in accordance with a certain straight direction, has a different motion pattern with the existing lithium-ion electrode materials such as cobalt. This is a coincidence with the original assume theory, the analysis results with the use of neutron diffraction, confirms that lithium iron phosphate (molecular formula is LiFePO4, also known as LFP) is able to ensure the security of large input/output current of lithium battery. [edit] The Physical and Chemical Properties of LFP The chemical formula of lithium iron phosphate is LiFePO4, in which lithium has +1 valence, iron has +2 valence and phosphate has -3 valence. The central iron atom together with its surrounding 6 oxygen atoms forms a corner-shared octahedron - FeO6 - with iron in the center. The phosphorus atom of the phosphate forms with the four oxygen atoms an edge-shared tetrahedron - PO4 - with phosphorus in the center. A zigzag three-dimensional framework is formed by FeO6 octahedra sharing common-O corners with PO4 tetrahedra. Lithium ions reside within the octahedral channels in a zigzag structure. In the lattice, FeO6 octahedra are connected by sharing the corners of the bc face. LiO6 groups form a linear chain of edge-shared octahedra parallel to the b axis. A FeO6 octahedron shares edges with two LiO6 octahedra and one PO4 tetrahedron. In crystallography, this structure is thought to be the Pmnb space group of the orthorhombic crystal system. The lattice constants are: a=6.008A, b=10.334A, and c=4.693A. The volume of the unit lattice is 291.4m3. The phosphates of the crystal stabilize the whole framework and give LFP good thermal stability and excellent cycling performances. Different from the two traditional cathode materials - LiMnO4 and LiCoO2, lithium ions of LiMPO4 move in the one-dimensional free volume of the lattice. During charge/discharge, the lithium ions are extracted from/inserted into LiMPO4 while the central iron ions are oxidized/reduced. This extraction/insertion process is reversible. LiMPO4 has, in theory, a charge capacity of 170mAh/g and a stable open-circuit voltage of 3.45V. The insertion/extraction reaction of the lithium ions is shown below: LiFe(II)PO4 <-> Fe(III)PO4 + Li + e- (1) The extraction of lithium from LiFePO4 produces FePO4 with similar structures. FePO4 also has a Pmnb space group. The lattice constants of FePO4 are a=5.792A, b=9.821A and c=4.788A. The volume of the unit lattice is 272.4m3. Extraction of lithium ions reduces the lattice volume, as is the case of lithium oxides. The corner-shared FeO6 octahedra of LiMPO4 are separated by the oxygen atoms of the PO43- tetrahedra and cannot form a continuous FeO6 network. Electron conductivity is reduced as a result. On the other hand, a nearly close-packed hexagonal oxygen atom array provides a relatively small free volume for lithium ion motion and therefore, lithium ions in the lattice have small migration speeds at ambient temperate. During charge, lithium ions and corresponding electrons are extracted from the structure, and a new phase of FePO4 and a new phase interface are formed. During discharge, lithium ions and the corresponding electrons are inserted back into the structure and a new phase of LiMPO4 is formed outside the FePO4 phase. Hence, the lithium ions of spherical cathode particles have to go through an inward or an outward structural phase transition, be it extraction or insertion[1] [2]. A critical step of charge and discharge is the formation of the phase interface between LixFePO4 and Li1-xFePO4. As the insertion/extraction of lithium ions proceeds, the surface area of the interface shrinks. When a critical surface area is reached, the electrons and ions of the resulting FePO4 have low conductivity and two-phase structures are formed. Thus, LiMPO4 at the center of the particle will not be fully consumed, especially under the condition of large discharge current. The lithium ions move in the one-dimensional channels in the olivine structures and have high diffusion constants. Besides, the olivine structures experiencing multiple cycles of charge and discharge remain stable and the iron atom still resides in the center of the octahedron. Therefore, putting the limit of electron conductivity aside, LiMPO4 is a good cathode material with excellent cycling performances. [3]During a charge, the iron atom in the center of the octahedron has a high spin state. [edit] Rapid Development of the LFT Upstream and Downstream Industries At present, the root patents of the LFP compounds are held by three professional material companies: Li1-xMFePO4 by A123, LiMPO4 by Phostech and LiFePO4 • zM by Aleees. These patents have been translated to very mature mass production technologies. The largest production capacity is up to 250 tons per month. The key feature of Li1-xMFePO4 from A123 is the nano-LFP, which converts the originally less conductive LFP into commercial products by modification of its physical properties and addition of noble metals in the anode material, as well as the use of special graphite as the cathodes. The main feature of LiMPO4 from Phostech is the increased capacitance and conductivity by appropriate carbon coating; the crucial feature of LiFePO4 • zM from Aleees is the LFP with a high capacitance and low impedance obtained by the stable control of the ferrites and crystal growth. This improved control is realized by applying strong mechanical stirring forces to the precursors in high oversaturation states, which induces crystallization of the metal oxides and LFP. These breakthroughs and fast development in upstream materials have drawn the attention of lithium battery factories and the automobile industry. It has prompted the developments of batteries and hybrid vehicles. LFP batteries and ordinary lithium batteries are both environmentally benign. The major differences between these two are that the LPF batteries do not have such safety concerns as overheating and explosion, have 4 to 5 times longer cycle lifetimes than the lithium batteries, have 8 to 10 times higher discharge power than the lithium batteries (which can produce an instant high current), and have, under the same energy density, 30 to 50 % less weight than the lithium batteries. The development of the LFP battery is highly valued by corporations such as the Department of Defense of the United States (for their hybrid tanks and Hummers), General Motors, Ford Motor, Toyota Motor, etc. A123 has been awarded, as a result, government grants for tens of millions of dollars, which are intended to support the U.S. industry of lithium batteries and to outscore the leading Japanese automakers in the development of hybrid vehicles. |
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Mar 2nd, 2009, 21:08
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只看该作者 #3 |
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Properties of LFP and Development of the Industry That being said, the market of hybrid vehicles is the determinant. It is the stable and safe olivine structure of LFP material that makes LFP favorable in lithium batteries. Different from other cathode material like Li-Co of layered structures and Li-Mn of spinel structures, LFP of olivine structures has strong oxygen covalent bonds and does not explode upon the short-circuit of lithium batteries. This feature might not be the most important for other mobile IT products but it is for lithium batteries installed on vehicles. (Note: Most consumers still prefer high-capacity but highly explosive Li-Co batteries even though many notebooks and cell phones over-heat and major Japanese companies often recall hundreds of thousands of notebooks.) According to US AABC’s statistics, one out of 70,000 hybrid vehicles (PHEV, HEV, BEV) using batteries containing cobalt or manganese will explode if they have the same incidence rate as the lithium batteries of notebooks and cell phones. This number is beyond the wildest estimation of automakers. What they give top priority is safety rather than capacity. The reason is simple: It is too expensive to recall automobiles, tens of thousands of times more expensive than recalling notebooks. Therefore, safety has to be weighed against battery life. Although LFP has 25% less capacity than other lithium batteries due to its material structure, it has 70% more performance than nickel-hydrogen battery. LFP’s improved capacity and stability draw automakers’ interests. For them, LFP can meet both the requirements of safety and battery life. Hence, hybrid vehicles are the critical market. According to statistics, HEV, PHEV, and BEV would have, in 2008, a market of at least 7 hundred million US dollars worldwide, and at least 5 billion US dollars by 2012. From 2008 to 2015, the sales of hybrid vehicles worldwide will increase by at least 12%. In 2012, the sales of hybrid vehicles in the US will exceed 1 million. Production of hybrid vehicles in Japan will increase 6.6% from 2008 to 2011. Over all, the market for hybrid vehicle batteries for will expand 10.4% from 2010 to 2015 and the markets of hybrid vehicle parts will increase 17.4%. In addition to compact vehicles, bus makers will also try to incorporate LFP batteries into their products. BAE has announced that their HybriDrive Orion 7 hybrid bus will use about 180KW LFP battery cells. Power plants are also using LFP now. AES in the US has developed multi-trillion watt battery systems that are capable of subsidiary services of the power network, including spare capacity and frequency adjustment. The GM CHEVROLET Volt is the first gas-electric hybrid vehicle to use these lithium battery materials. This Plug-in Hybrid Electric Vehicle (PHEV) which highlights the performance of fuel-efficient and comfort of driving will be officially go on the market in 2010,. Nearly 40,000 people in the United States have preordered this car; which will be able to run 60 km on one charge. It will also have a small gasoline engine which will be used to recharge the battery, so that the Volt can run longer during long-distance journeys. GM believes this PHEV will have an exceptionally high fuel economy, getting 150mpg. In Japan and mainland China, more and more lithium battery factories are joining this new type of lithium battery production, the goal being that eventually electric bicycles and buses using such batteries will be introduced onto the market. Before this new generation of materials can be used as the power source for electric bicycles, gas-electric hybrid vehicles and automation vehicles there lies one large obstacle: patents. Many of the companies that entered the field in the early stages have already received patents, which may result in other companies entering the market at a later time running into legal trouble. At present, the root patents of the LFP compounds are held by the three professional material companies: Li1-xMFePO4 by A123, LiMPO4 by Phostech and LiFePO4 • zM by Aleees. And these patents have been developed into very mature mass production technologies. The largest production capacity is up to 250 tons per month. The key feature of Li1-xMFePO4 of A123 is the nano-LFP, which converts the originally less conductive LFP into commercial products by modification of its physical properties and addition of noble metal in the anode material, as well as the use of special graphite as the cathodes. The main feature of LiMPO4 of Phostech is the increased capacitance and conductivity by appropriate carbon coating; the crucial feature of LiFePO4 • zM of Aleees is the LFP with the high capacitance and low impedance obtained by the stable control of the ferrites and the crystal growth. This improved control is realized by applying strong mechanical stirring forces to the precursors in high oversaturation states, which induces crystallization of the metal oxides and LFP. These breakthroughs and fast development in upper source materials, has drawn the attention of lithium battery factories and the automobile industry. It has lead some to surmise that this technology when applied to lithium batteries and gas-electric hybrid vehicles will give lead to a bright future for hybrid vehicles. LFP batteries and ordinary lithium batteries are both environmentally friendly. The major differences between these two are that the LPF batteries do not have such safety concerns as overheating and explosion, that the LPF batteries have 4 to 5 times longer cycle lifetimes than the lithium batteries, that the LPF batteries have 8 to 10 times higher discharge power than the lithium batteries (which can produce an instant high current), and that the LFP batteries have, under the same energy density, 30 to 50 % less weight than the lithium batteries. The development of LFP battery is highly valued in the industry, and has been developed for the United States Department of Defense's gas-electric hybrid tanks and Hummers, General Motors, Ford Motor, Toyota Motor and so on. A123 even obtained several ten million dollars in government grants, the purpose is to support the U.S. industry of lithium battery, use the development of gas-electric hybrid vehicles to stroke the leading Japan Automobile industry. From a development point of view, the U.S. auto industry estimates that by 2010, there will be over four million gas-electric hybrid vehicles on American roads. General Motors of the United States has decided to work towards the "large-scale production of electric cars" to break the domination of Japanese manufacturers. As U.S. consumers are under the extremely high pressure of skyrocketing oil prices, General Motors believe that the future auto market must be able to use all kinds of energy, and the electric car will be the key to success. Therefore, at the 2007 North American International Auto Show, GM unveiled the Plug-in Hybrid Electric Vehicle(PHEV) concept car "Chevrolet Volt Concept" and with the development of new GM hybrid system ( E-FLEX), one ordinary household power supply can be connected to the car for charging the lithium iron phosphate battery. When the Volt Concept reaches mass production, each car will able to reduce 500 gallons (1,900 liters) of gasoline consumption each year, and will reduce carbon dioxide output by 4400 kg. Facing such strong and unstoppable development, some industrial banks, venture capital funds and investment companies, have focused on the overall arrangement on the upper source material companies. In addition to the above-mentioned three companies, besides A123 in the United States, ActaCell Inc. just received 5,800,000 U.S. dollars funding from Google.org, Applied Materials (AMAT) Venture Capital and other venture capital firms. ActaCell’s main focus is to carry out the study outcome of University of Texas to the market. Professor Arumugam Manthiram has done a long-term study of development of spinel-based structure and superconducting materials. He served as a research assistant at UT, and then was promoted to professor. In recent years he discovered that when adding the expensive conductive polymers in the lithium iron phosphate (LFP), the grams capacity 166Ah/g of lithium iron phosphate (LFP) can be made in the laboratory, and then applied the microwave method to speed up the ceramic powder process of lithium iron phosphate (LFP). As to whether or not to circumvent the lithium iron phosphate (LFP) patents of A123, Aleees and Phostech by adding the conducting polymer, it is unclear at this current stage. However, the pace of the lower source industry is not slowing down at all, in Europe, BOSCH committed to the public by continuously expanding the automation and electric powered vehicle development in 2008. Some people in Europe believe the applications of the technologies are very limited. The traditional reciprocating engine may still have an advantage of 20 years, but eventually the vehicle electric vehicles will be able to catch up. BOSCH has a proud history of automotive technology research and development, and their own R&D department, which as a result of not looking to purchase technology from other corporations has been busy developing its own anti-lock brake and TCS tracking control system. They will be redesigned with a gas-electric hybrid computer program and will be featured in the VW Touareg and the PORSCHE Cayenne hybrid from BOSCH which will be on the market in 2010. BOSCH was one of the first companies that decided to focus and maintain a leading edge in fuel technology. Finally, others in the industry are beginning to wake up as the automotive safety becomes concerned about safety and now that alternative forms of energy are beginning to try to catch up. BOSCH believes they need to deeply explore the field of electric power, as it is going to be widespread technology worldwide. BOSCH and South Korea SAMSUNG are cooperating to develop lithium batteries and carry out mass production at a cost of about 4,000,000 U.S. dollars[4]. Although it is predicted that it will take about four to five years to move into the matured stage, BOSCH in any case will continue to invest in this effort in order to maintain its position as the top leader in the automobile technology. Another European automotive components assembler Continental, announced that their lithium iron phosphate (LFP) partners are A123 Systems and Johnson Controls-Saft. Continental will supply the batteries for Mercedes Benz. For dealings with Bosch, they may consider doing it themselves or purchasing from A123. For the security of the supply chain, they bought stocks from a small battery factory Enax in Japan, but the company is only capable of producing small voltage products. GS YUASA in Japan is a rising company that has announced the result of their work on the application of the anode of large-scale battery unit with its independently developed carbon-load of lithium iron phosphate (LFP). The tests results for external size of 115mm × 47mm × 170mm square shaped "LIM40" industrial battery unit indicated that even with the 400A large current discharge, the capacity is nearly not reduced. The original products without using the carbon load, had a 400A discharge unit that actually only had half the capacity of a 40A discharge. In addition, the trial product was usable in temperatures as low temperature as -20℃. In China, the two heavy-weight lithium battery manufacturers: BAK and Tianjin Lisen, also announced their building plans of the special LFP factories, which will have annual outputs of 20,000,000 lithium iron phosphate (LFP) batteries, will be completed at the end of 2008 and early 2009 respectively. The total amount of investment in their construction is 600million dollars. As for the upper source cooperative companies, they have yet to be found in the newspaper; the speculation is that they will be cooperating with one of the three lithium iron phosphate (LFP) vendors which has a production factory in Asia. As a result, by 2010, the competition landscape of lithium iron phosphate (LFP) industry in Europe, Asia and the United States, seems to have been decided more or less. With the high safety and stability of lithium iron phosphate(LFP) materials, the level of technology from each factory seems to be less important. The only decisive factor is the market price. According to general estimates, the union of lithium iron phosphate (LFP) will be able to lower battery price to 0.35 U.S. dollars per watt hours by 2010, will be able to take the lead in the rapid development of gas-electric hybrid vehicles and lithium battery bicycles, coming out as the ultimate winner. [edit] LFP Patent Wars Professor Goodenough at UT Austin, who discovered LFP of olivine structures more than ten years ago, probably would not expect that a micro material made of lithium iron phosphate (commonly used in fertilizers) could have such huge development and rapidly revolutionize many important industries. This prosperous development also elicits patent problems. Although A123 and Aleees do not think that their products have any patent infringements, so do their competitors: UT Austin and Hydro-Quebec, a Canadian water company. In the patent lawsuits in the US in 2005 and 2006, UT and Hydro-Quebec claimed that every battery using LiFePO4 as the cathode and the cathode material used in some lithium ion batteries infringed their patents, US patent No 5910382 and 6514640. The ‘382 and ‘640 patents claimed a special crystal structure and a chemical formula of the battery cathode material. Obviously, A123 and Aleees do not think they have infringed upon those patents since their cathode materials have different crystal structures and chemical formulae. On April 7th, 2006, in the district court of Massachusetts, the USA ruled, as a declarative precedent, that those LFP olivine materials with different crystal structures and chemical formulae did not infringe the ‘382 and ‘640 patents. The ruling and other relevant rulings forced UT Austin to revise the scope of the ‘382 patent and narrow its claims. Those companies owning LFP of different crystal structures went even further. On April 15th, 2008, the USPTO issued reviews of the revised claim and two new claims. So far, the review of the ‘640 patent is ongoing and this LFP patent war has not ended yet. On Dec 9th, 2008, European Patent Office revokes Dr. Goodenough’s LiMPO4 patent, patent number 0904607. This decision basically reduces the patent risk of using lithium iron phosphate in automobile application at Europe. The reason of this decision is believed to be based on the lack of novelty. While UT can still appeal the EPO decision, this result encourages the electric vehicle makers to pursue on lithium iron phosphate battery technologies. [5] While the patent war of LFP formulae and crystal structures is still going, it has involved many famous manufacturers of lithium batteries, such as Panasonic, ASEC (an energy supply subsidiary of Renault Samsung Motors), Johnson Controls-SAFT, Toshiba, Hitachi, Aleees, Enerdel, Altairnano, Mitsui Zosen, LG, Johnson controls, AESC, Valence, SAFT, ABB, E-one Moli. They are all trying to win this LFP patent war. The US government, too, has invested 55 million US dollars in LFP development. [edit] An Expensive Settlement: NTT Paid 30 Million US Dollars to UT as Settlement of the LFP Lawsuit This novel material will definitely make an important power device of PHEV, HEV, and BEV. However, the reason behind this trend is not the issue of climate change and carbon dioxide but of commercial profits. The first challenge of commercial products is patent infringement. Many of the pioneer companies in this field have exhaustive and thorough patent maps. Their followers often fall within these patent maps. The first case of an expensive settlement is the lawsuit between NTT Japan and UT.In October 2008[6], NTT announced that they would settle the case in the Japan Supreme Civil Court with UT by paying UT 30 million US dollars. Although UT agreed that NTT never stole UT’s business secrets, NTT was forced to share NTT’s patents of LFP materials with UT. NTT’s patent is also a kind of olivine LFP, with the chemical formula of AyMPO4 (A is for alkali metal and M for the combination of Co and Fe.). This compound is the same as what BYD is using now. (BYD gained substantial media exposure after Warren Buffet’s announcement of investing in BYD’s LFP hybrid vehicle project.) From the viewpoint of patents, AyMPO4 of NTT is quite different from LiMPO4 of UT and AyMPO4 has higher capacity than LiMPO4. NTT was forced to share its AyMPO4 with UT because its engineer - Okada Shigeto - was suspected of stealing UT’s business secrets. As a result, NTT lost an important edge in the development of lithium batteries. It is quite surprising that the ordinary grey LFP grains (Lithium Iron Phosphate) could induce so many patent lawsuits between western companies. [edit] Improvement of LFP Today, the major flaws of LFP that slow down LFP applications are low conductivity and low lithium diffusion constant. Researchers all over the world are working on improving the conductivity of LiMPO4. A123 is working around the problem of LFP’s extremely low conductivity (10-10 ~ 10-9 S/cm) by coating and replacing the material and converting the material into nano particles. Adding conducting particles in delithiated FePO4 raises its electron conductivity. For example, adding conducting particles with good diffusion capability like graphite and carbon [7] to LiMPO4 powders significantly improves conductivity between particles, increases the efficiency of LiMPO4 and raises its reversible capacity up to 95% of the theoretical values. LiMPO4 shows good cycling performance even under the condition of as large charge/discharge current as 5C [8]. Besides, coating LFP with inorganic oxides can make LFP’s structure more stable and increase conductivity. Traditional LiCoO2 with oxide coating shows improved cycling performance. This coating also inhibits dissolution of Co and slows the decay of LiCoO2 capacity. Similarly, LiMPO4 with inorganic coating, such as ZnO[9] and ZrO2[10], has a better cycling lifetime, larger capacity and better characteristics under the condition of a large discharge current. The addition of a conductive carbon in LiMPO4 increases the efficiency of LiMPO4, too. Mitsui Zosen Japan and Aleees reported that addition of other conducting metal particles, such as copper and silver, also increased LiMPO4’s efficiency[11]. LiMPO4 with 1 wt. % of metal additives has a reversible capacity up to 140mAh/g and better characteristics under the condition of large discharge current. [edit] Metal Substitution Substituting other metals for the iron or lithium in LiMPO4 can also raise its efficiency. A123 and Valence reported the substitution of magnesium, titanium, manganese, zirconium and zinc. Take zinc substitution for example. Substituting zinc for iron increases crystallinity of LiMPO4 because zinc and iron have similar ion radii [12]. Cyclic voltammetry also confirms that LiFe1-xMxPO4, after metal substitution, has higher reversibility of lithium ion insertion and extraction. During lithium extraction, Fe (II) is oxidized to Fe (III) and the lattice volume shrinks. The shrinking volume changes lithium’s returning paths. |
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Mar 3rd, 2009, 11:59
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只看该作者 #11 | |
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RYXTONY同学， 俺也是有文献的， 不是瞎杜撰的。请看: 1. 现在分析看来，比亚迪总裁王传福当初对电动汽车的“情有独钟”终于得到了最好的回报。比亚迪汽车有关负责人表示，F3e所拥有的核心技术，都是比亚迪坚持自主研发的结晶，对社会的环境保护、对全球的能源问题、对整个中国乃至世界汽车工业的发展都将产生积极的影响。而铁动力电池则是世界第一、全球领先，不仅突破了国内其他品牌的研发瓶颈，也彻底打破了世界汽车列强在核心技术领域的垄断，是中国汽车立足世界的基石，也是中国汽车工业迅速崛起的脊梁。http://www.automarket.net.cn 2. 。。。王传福认为这种铁电池成本更低、安全性和动力性更高，因而使电动力车离商用更近一步。“我们掌握了电动车的核心技术──铁电池，已在国内外申请700多项专利。铁电池原材料广泛、无污染、可回收，其耐热性、抗压性和容量都远远强于普通电池，电池充电循环次数可达2000次以上，电池的持续里程寿命大于60万公里。" (http://finance.sina.com.cn/chanjing/...55083290.shtml 3. 。。。揭秘“铁电池”2007年比亚迪最大的新闻点就是“铁电池”，具体这种电池是怎样的技术呢？记者采访了电池业内的知情人士，他表示：“比亚迪的‘铁电池’是磷酸铁锂电池，可能是出于宣传上的需要，简称为‘铁电池’，而实际上还是一种锂电池。” 这一点比亚迪公关部也承认“铁电池”的学名是磷酸铁锂电池。(http://auto.zjol.com.cn/05car/system...09118470.shtml) 4. 。。。在新近结束的北京国际车展上，宣称搭载了铁动力电池的比亚迪DM双模电动汽车赢得不少眼球，但有消息说，比亚胞d具有核心技术的“铁电池”其实并没有获得专利使用权。对此，比亚迪公关部经理王建均在接受记者采访时未正面澄清质疑，只是表示该公司“推出新能源车的计划没有改变”。 此次北京车展上，比亚迪双模电动车F3DM和F6DM，以及纯电动车e6全面亮相，并以其实现了既可充电又可加油的多种能量补充方式而备受关注。据了解，被比亚迪自称为“核武器”的铁动力电池，其实质是磷酸铁锂电池。 记者通过中国知识产权网查阅有关磷酸锂铁专利方面的信息，没有发现比亚迪名列其中。据一匿名业内人士透露，磷酸铁锂电池专利的拥有者是美国德州大学。而德州大学目前正在与全球最大的磷酸铁锂电池供应商A123 Systems进行专利诉讼，控告其在未获得电池技术授权的情况下制造与销售侵权商品。该人士还认为，这说明比亚酊7d在高速发展的背后，还是有很多基础功课并没有做扎实。 网上近日也有传言，“比亚迪董事长王传福在08北京车展期间接受sohu汽车频道‘中国汽车制造业未来发展十年’总经理论坛主持人访谈时承认没有铁电池的专利，比亚迪的铁电池是要向国外的电池专利所有人购买的。” 面对铁电池专利质疑，比亚迪公关部王经理一再顾左右而言他，“在国内，比亚迪是第一个将磷酸铁锂电池运用在汽车上的。同时，我们推出新能源车的计划没有改变。” (http://it.hexun.com/2008-05-09/105840680.html) 不过关于这个"比亚迪独门秘笈"，水比较深; 究竟鹿死谁手，估计一时半会儿还说不清。 请宁可信其有， 不可信其无， 就当支持国产吧  引用:
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Mar 3rd, 2009, 15:09
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只看该作者 #16 | |
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引用:
Hydro-Québec的前身是La Commission Hydroélectrique du Québec，从建立之初一直没有被国有化；后来魁独英雄，魁人党党魁René Lévesque把它国有化了。核电站建立在Bécancour，充分利用了Fleuve Saint-Laurent的水资源。 |
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