Why do e-bike batteries explode? - Page 1
Forum section: electronics / general

author: avandalen
author_rank: Contributor
timestamp: September 03, 2023, 09:24:56 am
content: I have researched dangerous and deadly e-bike batteries, see my article:https://avdweb.nl/solar-bike/batteries/the-cause-of-e-bike-battery-firesAlbert van Dalen

author: Faringdon
author_rank: Super Contributor
timestamp: September 03, 2023, 09:55:38 am
content: A properly built lithium batt pack is actually quite hard to explode...take formula E where in the pitstop, they massively overcharge the E batteries, but they dont explode....just smoke a bit.The reason these tragedies happen is because as you describe in your link, the packs arent properly made.The reason for that is that the British (insert your own country there) middle men who import these things, crush the Chinese electronics co's down on cost, since the Brit middle men dont know anything about electronics....and just want to make a quick buck..[This post is not anti-China, the Chinese are perfectly honourable in all this....its the Brit middle men.....and more pertinently, the "system" under which they operate]These same middle men, always operate "token" electronics companies in UK (insert your own...) .....which they use as a "shop-front" to bring customers in and make them think the company knows about electronics.In fact, its damned hard to stay in business in electronics today in UK (insert your own country) and NOT run a secret, backroom, import-from-China business......which inevitably becomes the big profit earner. The import business is kept secret in the "backroom".So these fires will keep happening until these things are brought out into the open.....which they likely will not be.

author: Gyro
author_rank: Super Contributor
timestamp: September 03, 2023, 11:53:04 am
content: It's a shame that these sort of companies (if there is any truth in your oft-repeated tales) are the only ones prepared to take you on. It has clearly given you a very warped view of professional UK and European engineering companies. It also shows very poor judgement on your part that you can't spot, and are willing to take up positions with, such 'dodgy' entities.

author: Bud
author_rank: Super Contributor
timestamp: September 03, 2023, 12:52:20 pm
content: @Faringdon you keyboard has sticky Dot key.

author: magic
author_rank: Super Contributor
timestamp: September 03, 2023, 01:03:20 pm
content: He isn't wrong, though. "These sort of companies" rule the low-end consumer market.Speaking of power supplies, I own a nice ATX PSU, bought locally and completely legal with the "China Export" sticker and everything, which uses linear regulator to drop 5V to 3.3V, with a paper thin heatsink and no OCP, OTP or anything. The model used to be fairly common in its day and curiously there are several reports on the Internet of it literally catching fireThis is what you get going to Amazon or similar and sorting by price. Or even by popularity or feedback, because it may not catch fire right away for everyone.

author: nctnico
author_rank: Super Contributor
timestamp: September 03, 2023, 01:07:52 pm
content: Quote from: magic on September 03, 2023, 01:03:20 pmYep. A long time ago I helped a battery manufacturer through the startup phase. I went along to quite a few e-bike manufacturers (as their engineer) and they all had the same problem: reliability issues with batteries sourced from China. Today the battery manufacturer is a major player; you can still compete on quality.

author: BrokenYugo
author_rank: Super Contributor
timestamp: September 03, 2023, 03:14:41 pm
content: Probably resleeved recycled mystery cells too.It's such a problem I don't think your average consumer has a chance of acquiring a properly built ebike battery, especially as a battery alone. Too much room for error, fake shit in the supply chain, etc. My parents bought a pair of supposedly decent ebikes, no fire yet but the chargers look and feel about on par with a cheap ebay laptop brick (uncertified junk), so I have my doubts about battery quality.

author: jonpaul
author_rank: Super Contributor
timestamp: September 03, 2023, 03:29:28 pm
content: low quality poor;y made and poorlyu designed cells/batts from China, non comliant non fail safe chargers masquerading as CE/UL/VDE apprived, user error in match of battery and chargej

author: janoc
author_rank: Super Contributor
timestamp: September 03, 2023, 04:37:29 pm
content: Bashing cheap Chinese no-name junk is quite cheap but unfortunately the name brand battery manufacturers aren't immune to this issue and the resulting battery fires either. The issue is much more complex than just "cheap people buying cheap low quality junk."I have worked the last half a year on a product designed to non-destructively analyze and check Li-ion batteries, the kind you would find in anything from power tools to cars (even from the largest names in the EV market). The cheap appliance batteries aren't checked/inspected at all during production, only visual checks for damage are done and spot checks on selected cells from a batch are done with more comprehensive testing for QA and process control purposes. So you can easily get a lemon battery for your phone, laptop or e-bike where the internal layers/electrodes are kinked or touching, causing a short and a fire even from major names like Samsung.Batteries for cars are inspected more rigorously but still, pretty much nobody does 100% inspection of assembled batteries. It is not possible to do non-destructively except by x-raying and inspecting every single cell. Even normal x-ray is not enough, one has to use computer tomography to look at the cell from multiple angles. This is a very costly and time consuming process, so it isn't done systematically on 100% of cells either. There are some battery vendors heavily investing in this equipment but given that a single CT scan takes minutes (in the best case!) and we are talking about production lines spitting out thousands of cells every hour, you can imagine how much would 100% inspection cost in terms of CT hardware, operating costs, etc.And this covers only sorting out cells that are defective during manufacture already due to some process failure (assembly issues, delaminations, etc). Cells can and do fail later as well, for various reasons, the electronics could fail, the cells could overheat because of poor cooling or ambient temperature triggering a runaway, etc.The worst issue is that even the manufacturers themselves don't really know what will make the battery fail later in its life. There is some empirical knowledge, such as if the anodes are not overhanging the cathodes inside the battery sufficiently or the anodes are too deformed it is likely a short will occur and such battery should be recycled but beyond that it is mostly guesswork. There isn't really anything like a DIN or ISO norm for Li-ion batteries and when there is an EV fire it is very rare that the battery gets taken apart to investigate what caused it (or that you even have anything to take apart after the fire).Even worse - each manufacturer has their own, completely proprietary, processes and criteria. We had huge problems even getting examples of how a good and a bad battery looks like from them in order to be able to actually make that tool - it is all considered proprietary information, trade secret because the market is so competitive.I really do hope we get some less "explosive" chemistry soon and Li-ion will put out to pasture.

author: nctnico
author_rank: Super Contributor
timestamp: September 03, 2023, 04:52:42 pm
content: Quote from: janoc on September 03, 2023, 04:37:29 pmI fully agreeBut I'm afraid manufacturers are holding off/delaying new chemistries in order to recoup the investments in Li-ion.

author: janoc
author_rank: Super Contributor
timestamp: September 03, 2023, 05:47:08 pm
content: Quote from: nctnico on September 03, 2023, 04:52:42 pmGiven the millions it costs to buy a single CT machine for battery inspection, the battery manufacturers would have switched to a safer chemistry yesterday if there was one available - with the same or higher energy density, number of cycles and comparable cost. And, obviously, one that is actually possible to make in volume because the processes are worked out. The factory equipment to make those batteries is +/- the same. Also, it wouldn't explain the giant investments into building new factories these last few years to churn out li-ion cells for automakers if there was an actual safer chemistry available for them to use. Tesla, VW or BMW don't care what is the chemical mix inside the batteries - they need reliability, capacity and cost. They have zero interest in somehow trying to sabotage alternative chemistries, esp. given they are actively invested in the battery R&D themselves and it has direct impact on their bottom lines.Unfortunately, there isn't one so far. There are plenty of announcements of revolutionary tech here and there, startups are getting millions in VC money - but Li-ion is still the winner when it comes to actual battery production. There is a huge difference between something working in a lab and being able to produce reliable cells in a volume that e.g. the car or solar power industry need. Right now the only semi-viable production-ready alternative is lithium-phosphate but those cells have a lot lower energy density, so they aren't really suitable for vehicles where customers demand hundreds of km range or appliances where size and weight are important.

author: Zero999
author_rank: Super Contributor
timestamp: September 03, 2023, 06:49:26 pm
content: The authorities really need to clamp down on illegal e-bikes and scooters. I nearly ran someone over yesterday. I was on my motorcycle, which is quite noisy, so I would have hoped they would have heard me coming and an idiot on an e-scooter suddenly crossed the road in front of me. Fortunately I managed to brake, swerve and avoid hitting him.I don't advocate banning them. They need to have insurance and a licence to ride and laws should be properly enforced.

author: janoc
author_rank: Super Contributor
timestamp: September 04, 2023, 07:59:50 am
content: Quote from: Zero999 on September 03, 2023, 06:49:26 pmThat an idiot cuts you off/doesn't yield doesn't make their vehicle illegal. You could be equally well cut off by a cyclist or a careless pedestrian.Re mandatory insurance - that is already on the books and coming, at least EU-wide.And license - hm, not going to happen. That particular genie is long out of the bottle, demanding that every teen needs a license to ride their scooter now is not workable. Not to mention that in many EU countries small gasoline scooters and even "minicars" are possible to drive without a license for a long time.

author: Jeroen3
author_rank: Super Contributor
timestamp: September 04, 2023, 09:50:35 am
content: Nice teardown showing incompetent battery design!It's what you get for lack of accountability for reasons Faringdon dove into.However, you skipped over the reason. Batteries can explode because they contain a chemical reaction with potential energy.When this reaction is poorly handled, monitored and managed there is the possibility to release all of the energy in a short time.The containment for the chemical reactions can't handle this.Fire.

author: Zero999
author_rank: Super Contributor
timestamp: September 04, 2023, 01:23:00 pm
content: Quote from: janoc on September 04, 2023, 07:59:50 amI know the law where I live and it was obvious the vechicle was illegal: small wheel/tyre size, not pedal assist, no number plate and mirrors. It was weaving and wobbling around all over the road. Even if driven carefully, it's still a death trap, because a drain cover or small pot-hole would be enough to cause it to fall over.

author: Psi
author_rank: Super Contributor
timestamp: September 04, 2023, 01:28:23 pm
content: Pretty common with any new tech. It takes a while to figure out the right way to do things.Usually doing things the wrong way doesn't start fires, but in this case it does.We're in a rapid EV growth and innovation phase atm, lots of companies trying many different things to see what works, what doesn't and what they can get away with.

author: mtwieg
author_rank: Frequent Contributor
timestamp: September 04, 2023, 05:06:56 pm
content: Quote from: Psi on September 04, 2023, 01:28:23 pmWell I think the proper ways to manufacture and test cells and battery packs (at least for common cell types like 18650) have been known for years. The problem is that it's clearly possible to make a profitable business without actually applying proper processes and QA.I think the foundation of any solution has to be a standard for traceability for the whole Li battery industry, covering individual cells up through finished packs (ideally for cell materials, but probably not feasible). AFAIK no such system exists presently. It such a thing ever does exist, it will probably emerge from China, since they seem to be the dominant producer and consumer of these batteries right now.

author: dietert1
author_rank: Super Contributor
timestamp: September 04, 2023, 05:36:03 pm
content: When it comes to fire risk, does it depend on the charge state of a battery? Maybe a discharged battery won't burn that strong. I was thinking about that ship havoc, where i assume conventional vehicles get shipped with very little gasoline inside to reduce the fire risk.Regards, Dieter

author: magic
author_rank: Super Contributor
timestamp: September 04, 2023, 05:52:34 pm
content: Quote from: Zero999 on September 04, 2023, 01:23:00 pmEvolution is the solution; keep safe distance from idiots and enjoy

author: madires
author_rank: Super Contributor
timestamp: September 04, 2023, 08:03:12 pm
content: Chinese E-Bikes are Exploding like Crazy - Self Destructing Spectacularly, by serpentza

author: DavidAlfa
author_rank: Super Contributor
timestamp: September 04, 2023, 08:15:52 pm
content: Maybe because the first thing people do is to modify the fw to supply 2-3x the power, so it makes 25mph uphill.Or they mess with the batteries, adding more cells (Ultrafire brand does what it promises), with absolute zero knowledge, using some random Aliexpress BMS.Maybe no temperature sensors, terrible solder joints in the cells themselves made with some crappy 20W iron, about to come off anytime.

author: Psi
author_rank: Super Contributor
timestamp: September 04, 2023, 09:37:58 pm
content: Making battery packs with this many cells carrying this much power is new, so is uncovering new problems.But yeah, QA/QC is a big issue. everyone is rushing too quickly to get on the EV bandwagon and it's causing problems. Not enough thermal/vibration/accelerated life testing etc..To be fair, if I owned an accelerated life testing lab i'm not sure I would want to test high capacity battery pack on my equipment to insure they doesn't catch on fire.My fee's would be super high to pay for replacement/insurance etc.. Which is one more reason why they don't do it and why we have the issue.

author: tridac
author_rank: Regular Contributor
timestamp: September 09, 2023, 01:11:50 am
content: That's down to the importer, trying to get the cheapest solution. China will build to any you quality you like, as will other far east countries, but spec and buy cheap, and cheap is what you get...

author: Rick Law
author_rank: Super Contributor
timestamp: September 10, 2023, 08:09:21 pm
content: Quote from: madires on September 04, 2023, 08:03:12 pm+1 for Madries's post and link.Winston (Serpentza) is rather insightful. His videos are informative and well made. A South African by birth, having escaped death at least, he moved to China living there for years. He ended up escaping China also. He did IT work, Body Guard, English Teacher, so on, just to make his life work. With his wider perspective, he isn't just another run of the mill youtube loud mouths.His video explained well how E-Bikes in China became became so prolific and cheap. His video on burning BYD EV's is another good one to look at as well...