The Arizona lab fire showed the challenges facing Boeing’s strategy to safely manage that energy, prevent such a blowout and contain any less serious battery problems.
亚利桑那实验室火灾,波音面临巨大挑战。如何控制这些(电)能量,防止爆炸,控制电池的小毛病。
By Dominic Gates
多米尼克-盖茨
Seattle Times aerospace reporter
西雅图时报航空航天记者
Seattle Times aerospace reporter
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In 2006, a devastating lab fire in Arizona showed just how volatile Boeing’s 787 Dreamliner lithium-ion battery can be if its energy is not adequately contained. 2006年,亚利桑那州的一间实验室起火,向人们显示,如果不能有效地控制这些能量,787梦想飞机的锂电池火灾会多么凶猛
A single battery connected to prototype equipment exploded, and despite a massive fire-department response the whole building burned down.
连接在验证设备(试验阶段机载设备未取证)的一节单独的电池爆炸,尽管消防局尽职尽责,整座实验室还是完全烧毁。
On the finished Dreamliner, however, Boeing is confident its engineers can safely harness and contain that energy.
波音对制造完成的梦想飞机还是有信心的,认为它的工程师能控制这电力问题。
The 787’s battery-fire protection regime aims both to make a catastrophic blowout impossible through multiple independent controls and also to compartmentalize any less serious battery meltdown, venting smoke outside until the high-temperature reaction burns itself out.
787的防火设计目标是,通过多重各自独立控制系统,把灾难性大喷发的可能性降低到0;同时把不那么严重的电池融毁局限在局部舱室之内,排出烟雾,最终(只是)故障的电池自身高温烧毁。
That approach was approved by the Federal Aviation Administration (FAA), with special conditions attached.
这种途径被FAA有特殊条件限制地批准。
Yet the All Nippon Airways (ANA) 787 emergency last week suggests Boeing's containment plan — even if the engineering is technically solid — may not work for airlines in operational terms.
全日空787紧急降落事件说明,波音的方案即使工程上是可行的,但不是航空公司所希望的。
In the ANA incident, the pilot made an emergency landing when he received warnings of an overheated battery and smelled a burning smell in the cockpit.
在这次事件中,飞行员收到电池过热警告并闻到烟味,随即作出紧急降落的决定。
“If I’ve got an unexplained source of smoke or smell and messages indicating an overheat or a fire has been detected, frankly, I’m not going to pull out the book,” said veteran airline captain and aviation expert John Nance. “I’m just going to get the ship on the ground.”
“如果我闻到不明来源的烟味,收到过热或火警信号,实话实说,我不会去查故障手册”,资深机长/航空专家约翰-南斯说:“我肯定会快快地驾机降落”。
Unless such events will occur only very rarely, Boeing’s engineering solution won’t be tenable as a practical matter.
如果这类事件是极小概率事件,波音的工程方案还是行得通的。(这句怎么这么别扭?)
Two 787 battery incidents in quick succession out of 18,000 in-service flights so far isn’t close to rare enough. That’s why the jet fleet is grounded worldwide as investigations continue.
两架787飞机电池事故接连发生,所有787飞机至今累积飞行1万8千个航班(那么多了?),这不能算是极小概率。这就是全球范围内787机队停飞的原因。
The Air Line Pilots Association (ALPA) raised concerns about Boeing’s battery-fire-protection plan in the course of the FAA certification process.
在FAA取证阶段,航空公司飞行员协会(ALPA)就对波音的电池防火方案表示了担心。
During the public-comment period in 2007, the pilots union stressed that “a fire from these devices, in any situation, is unacceptable.”
在2007年公示阶段,飞行员工会强调:“在任何情况下,这些设备起火都是不可接受的”。
ALPA quoted a 2006 FAA report on transporting lithium-ion batteries as cargo, which concluded that a relatively small amount of heat is sufficient to cause the flammable chemical inside a lithium-ion cell — called an electrolyte — “to forcefully vent ... through the relief ports near the positive terminal.”
ALPA援引2006年FAA一份锂电池货物运输的报告,那份报告中的结论是,相对少的热量也足以使锂电池中的可燃化学物质——电解质—从正电极附近的减压孔释放出来。
“The electrolyte is highly flammable and easily ignites when exposed to an open flame or hot surface,” the FAA report added.
这份FAA报告接着写道:“这种电解质在接近明火或者热的表面时,是非常易燃的”
People familiar with the investigation so far confirm that electrolytes sprayed out of the battery in the ANA jet, leaving a dark sooty residue across the electronics bay. Photos show the insides of the battery burned out and blackened.
熟悉这次调查的人确认,ANA的787上,电解质飞溅,在电子舱留下了深色的残余物。照片显示电池内部燃烧成了黑色。
The 787 carries two large lithium-ion batteries.
787有两个大的锂电池组。
One in a rear electronics bay is used mainly to start the plane’s auxiliary power unit; the other in a forward bay is used to start the main engines.
一个在后电子舱主要用于启动飞机的辅助动力装置APU;另一个在前电子舱,用于启动两台大发。
In an emergency, the two batteries provide backup power for flight-control electronics and emergency lighting.
紧急情况下,这两个电池组给飞行控制电子设备和应急灯供电。
The forward electronics bay that housed the malfunctioning ANA battery is like the “brains” of the airplane, filled with critical flight-control equipment.
前电子舱是飞机的“大脑”,关键的飞行控制设备都在这里。ANA出事的电池就安装在这里。
Extinguishing fires
灭火
In its 2007 comments, the pilots union initially asked that the FAA require “means for extinguishing fires” caused by the lithium-ion batteries.
2007年的质询中,飞行员工会要求FAA对锂电池起火作出“灭火措施”的要求。
However, in a subsequent email to the FAA later that year, the union switched gears and asked that the focus be “preventing a fire and not reacting to one.”
然而,当年晚些时候,给FAA的后续电子邮件中,工会变了口径,要求着重于防火而不是灭火。
ALPA did not respond to requests for comment Wednesday.
ALPA周三没有对此评论作出反应。
In any case, the FAA decided not to require fire suppressant in the electronics bay, and Boeing didn’t include it.
不管到底发生过什么事情,FAA决定不对电子舱灭火作出要求,波音也就没有相应的设计。
Mike Sinnett, Boeing vice president and chief 787 project engineer, explained why in a conference call last week and detailed Boeing’s engineering solution.
麦克-斯奈特,波音副总经理/787项目总工,对此作出解释。
To completely rule out any catastrophic high-energy fire or explosion that could result from overcharging a battery, Sinnett said, Boeing designed four independent systems to monitor and control the battery charge.
为了排除任何可能有电池过充引起的灾难性火灾或爆炸,斯奈特说,波音设计了四个独立的系统检测和控制电池充电。
However, he conceded that if an internal cell shorts and overheats, “the electrolyte can catch on fire and that can self-sustain.”
然而,他退一步说,如果电池内部短路过热,“电解质会发生自持续性(不需要外界因素)火灾。”
“Something like that is very difficult to put out,” Sinnett said. “Because the electrolyte contains an oxidizer, fire suppressants just won’t work.”
“或者说,引起火灾的要素非常难以排除”,斯奈特说“因为电解质本身含有氧化剂,灭火剂基本不起作用”。
Boeing’s design solution is to contain that outcome until the combusting battery cell or cells burn out.
波音的设计思想是,把火情局限在一个局部区域直到电池自燃完毕。
“You have to assume it’s not going to go out,” Sinnett explained. “You have to assume that it’s going to go and that it’s going to expend all of its energy.
“(设计思想是)假设不会起火,”他解释,“(或者)假设起火(那就得等到)它释放完所有的能量”。
“You have to be good with the amount of heat and smoke that’s generated from that event,” he added.
“飞机必须能承受这种事件产生的一定的热量和烟雾”
Sinnett pointed out that the air flow in the electronics bay will be redirected when smoke is detected, so that the smoke is vented overboard, not into the passenger cabin or cockpit.
斯奈特指出,探测到烟雾后,电子舱里的流动空气将被转向排出机身,而不是吹向驾驶舱和客舱。
Nance, the veteran pilot, said he assumes Boeing’s engineers have got that right — in which case, it’s possible the incident on board the ANA jet played out as they intended.
资深飞行员南斯说,他假设波音工程师们正确,那么ANA的当事飞行员是有可能按照波音预期的那样操作的。
But still, he said, Boeing “may not have adequately planned for the number of potential incidents” that might occur during a jet’s lifetime.
但是,他说,波音“在这么短的时间内发生这种事件(次数),可能出乎波音预料之外”。这种事件在飞机的寿命之内有(不大的)可能性发生。(波音这么认为)
Calculating how often this kind of event might happen requires knowledge of the root cause of this month’s battery incidents. The cause, or causes, remain unknown.
计算本月发生的这种电池事故发生频率,可能需要对事故发生的根本原因有深层次的理解。而这个起因,或者这些起因,至今不明。
If it was a bad batch of batteries, the number of malfunctions could be reduced with higher quality control in the manufacturing plant.
如果只是某个批次电池有问题,那么通过质量控制,可以减少事故频次。
If it’s something inherent in the battery design, Boeing may be forced to switch from lithium ion.
如果与电池设计有关,那么波音可能被迫放弃使用锂电池。
At least aviation-safety regulators appear close to ruling out, if not yet definitively, the worst-case scenario of a potentially explosive overcharging:in the two recent incidents.
至少适航当局已经接近排除,如果还不能说确定的话,这两起电池事故中过度充电。(即:这两次基本可以肯定不是因为过度充电)
Japanese aviation-safety regulators said Thursday that the overheated battery aboard the ANA Dreamliner flight last week didn’t seem to be overcharged.
日本适航当局周二说 ,ANA的梦想飞机电池起火看来不是过充引起的。
Their U.S. counterparts concluded the same about the battery that caused a fire on a Japan Airlines Dreamliner in Boston the previous week.
美国适航当局(FAA)对日航787波士顿机场电池起火作出同样的结论(不是因为过充)。
Battery testing
电池测试
The potential dangers of the 787’s lithium ion batteries were made vividly apparent in a 2006 incident when a single battery ignited during testing in a lab run by Securaplane Technologies of Tucson, Ariz.
2006年在亚利桑那州图桑的Securaplane Technologies公司的实验室里,787锂电池起火,人们见识到了将来可能发生的787锂电池火灾。
While Japanese company GS Yuasa manufactures the Dreamliner batteries, Securaplane makes the charging-control system. Both components are integrated into the overall electrical system by Thales of France.
日本的GS Yuasa公司制造电池,Securaplane公司制造充电控制系统,最后由法国的Thales公司集成到飞机电力系统中。
During testing of a prototype charging-system design in the 2006 incident, “the battery caught fire, exploded, and Securaplane’s entire administrative building burned to the ground,” according to a summary by the administrative law judge in a related employment lawsuit.
在2006年的那次测试中,法院在审理相关诉讼时,总结:“电池引起火灾,爆炸,Securaplane公司的整个行政楼烧为灰烬。”
The ruinous fire resisted the initial efforts of two employees with fire extinguishers, and escalated, despite the dispatch of a fleet of fire trucks, to destroy the 10,000-square-foot building.
当时有两位员工用灭火器试图灭火,火势升级,尽管消防局的大队人马出动,1万平方英尺的大楼还是灰飞烟灭。
It reached temperatures of about 1,200 degrees and resulted in losses of millions of dollars.
燃烧达到1200度的高温,造成几百万美元的损失。
The cause of the battery explosion was not firmly established. The battery may have been overcharged, and human error in the testing was not ruled out. Indeed, Boeing insists it was an improper test setup.
电池爆炸原因并未确定。电池可能过充,人为因素也未被排除。波音坚持那次实验本身就有问题。
However, a local fire district’s summary lists one of three possible causes as “a battery malfunction due to the batteries [sic] composition.”
然而,当地消防部门列出了三个可能原因,其中之一是:“一个电池因为其中电池的组成物质而起火”。
And, apparently referring to the same possibility, the legal summary in 2011 says one possible cause is “a defect in a small corner of a cell.”
2011年的一份法律文件也说可能的原因之一是“一个电池的一个小角存在缺陷”。
The FAA investigated the Securaplane incident in 2008 and 2009.
FAA于2008-2009年调查了Securaplane火灾。
“The investigation determined that the battery-charging units in the complaints were prototypes, and none are installed in Boeing 787 aircraft,” the FAA said in a statement in response to questions about the incident.
FAA在回答有关提问时说:“经调查,测试中使用的充电器是验证产品,787飞机上没有安装这种充电器” 。
Sinnett, Boeing’s 787 engineering chief, said the company is ready to deal with the investigation’s conclusions and adjust its design accordingly.
波音787项目总工斯奈特说,公司将根据调查结果对设计作出相应调整。
“Information will come in, we’ll challenge our assumptions, and if we need to make some changes, we’ll make those changes and we’ll move on,” he said.
他说:“将会收到(调查)信息,我们会反思质疑我们先前的假设。如果需要我们做改变,我们将做那些改变,我们将继续努力”。
Seattle Times staff reporter Steve Miletich contributed to this report. 作者: 天柏 时间: 2013-1-26 13:08
Unless such events will occur only very rarely, Boeing’s engineering solution won’t be tenable as a practical matter. 应该翻为:除非此类事件发生的几率极小,波音的解决方案在实际应用中是行不通的。