Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Bill Sloman Newsgroups: sci.electronics.design Subject: Re: lithium explosion Date: Sat, 13 Apr 2024 16:06:40 +1000 Organization: A noiseless patient Spider Lines: 66 Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Injection-Date: Sat, 13 Apr 2024 08:06:56 +0200 (CEST) Injection-Info: dont-email.me; posting-host="18cfad8459c755af471d45d3e7233960"; logging-data="3012175"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+Y108RpQbd8xBmqQ8QzwUII+pWn13F1FA=" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:pMtboL7OqlCuvKxB9ct1vf+MaQY= Content-Language: en-US In-Reply-To: Bytes: 3847 On 13/04/2024 12:21 am, John Larkin wrote: > On Fri, 12 Apr 2024 13:16:40 +0200, "Carlos E.R." > wrote: > >> On 2024-04-12 07:19, Bill Sloman wrote: >>> On 9/04/2024 3:03 am, Jeroen Belleman wrote: >>>> On 4/8/24 18:35, John Larkin wrote: >>>>> https://www.bbc.com/news/uk-england-london-68744317 >>>>> >>>>> It doesn't look like that one was charging. >>>>> >>>>> Lithium battery fires are a big deal in New York too. >>>>> >>>>> San Fancisco is swarming with illegal, unlicensed electric scooters, >>>>> surfboards, wheelie things, bikes, and motorcycles. >>>> >>>> As the energy density of batteries goes up, failures will >>>> become more spectacular. It's not a good idea to store >>>> both oxidizer and fuel in close proximity in the same >>>> container. It's a recipe for an explosive. >>> >>> Lithium batteries don't explode spontaneously. >>> >>> The "explosion" is actually the last stage in a process that starts when >>> the batteries start self-discharging more rapidly than they should, >>> which warms them up a little. >>> >>> Any properly designed battery management system monitors this >>> self-heating, with temperature sensors at the core of the battery, and >>> on it's surface. >>> >>> If the battery gets hot enough, the higher temperature can lead to a >>> higher discharge rate, and at a battery temperature between 130C and >>> 160C which depends on the battery chemistry, the process can run away >>> leading to something that looks like an explosion. >>> >>> Any properly designed designed battery management system would warn the >>> user when this were incipient and would start discharging the battery if >>> it had a safe place to dissipate the stored energy. >>> >>> It follows that any lithium battery pack that explodes either didn't >>> have a properly designed battery management system, or was being looked >>> after by somebody who ignored the early warnings. >>> >>> All this is too complicated for John Larkin to keep in mind - we've >>> discussed it here often enough that he should know it by now. >> >> Or the battery wasn't attended. >> >> Battery fires have happened when nobody was near the battery; maybe >> charging. > > Or just parked somewhere, not charging. I wonder how long it takes a > tiny separator defect to spread into an explosive meltdown. Some > references suggest seconds. And who thinks that separator defects lead to thermal run-away and battery ignition? John Larkin does pick up on other people's silly ideas, and has a few of his own - not all that many or he'd have got himself a patent or two. -- Bill Sloman, Sydney