Battery Fires

This might help with understanding. His summary seems to be that it's individual cell quality that leads to fires, though I only skipped through it so far:

one thing that puzzles me a long time. I am amazed that nobody has thought of killing the electrolyte or one of the electrodes to prevent the thermal runaway.

one thing that puzzles me a long time. I am amazed that nobody has thought of killing the electrolyte or one of the electrodes to prevent the thermal runaway.

That's what he explains in the video. Some cylindrical cells have tops that pop like fuses.

that's the anti-explosion device, just for controlled venting. You need to poison the electrolyte to stop the conduction through the electrolyte. If you act fast enough, that would prevent the electrolyte from heating up.

OK

that's the anti-explosion device, just for controlled venting. You need to poison the electrolyte to stop the conduction through the electrolyte. If you act fast enough, that would prevent the electrolyte from heating up.

OK, thanks. I have some Alphachloralose left over from the rats. I'll put some in my toolkit and chuck it on the battery when it catches fire. I never though of that.

Aaarrrgggh! He says here that quick blow automotive fuses don't always blow quick. I might double or triple them up, increase the odds of a quick blow.

 

https://www.youtube.com/watch?v=j92Gt4VviSQ:842

thermal runaway in lithium battery is usually caused either by external short circuit (damaged BMS by overcharging for example) or internal short circuit (damaged separtator for example).

To improve the separator. manufacturers now re-inforce them with ceramics.

This is not a mature technology yet, is it. So many ways it can become unreliable or as in this case very dangerous. I was just reading an article in the Guardian about the experience of a Renault electric car owner being quoted £7500 for the replacement of the charging module in his car because it had burned out. Huge numbers of garages won't touch them.... Not surprised. A shock from an 800v battery is unlikely to leave you in a good state or even alive. The massive current available would be very unforgiving. I once got an 800v shock from a fat capacitor. A few milliamps. It wasn't nice. Threw me across the room. From a battery it would be a very different story.

 

I just bought a new car and thought about Electric power, but went petrol. Maybe by 2035 they will be better.

 

I'm wondering how the much talked about Toyota solid state batteries will turn out. Toyota have a history of announcing marvellous new tech that comes to nothing though. They are supposed to offer high energy density, rapid charging, many charge cycles and no risk of fire. If it is true it would be a revolution.

I'm wondering how the much talked about Toyota solid state batteries will turn out. Toyota have a history of announcing marvellous new tech that comes to nothing though. They are supposed to offer high energy density, rapid charging, many charge cycles and no risk of fire. If it is true it would be a revolution.

 

Nissan have announced that they will have a solid state battery model on the road in 2028, and they have lead the way with lithium batteried e-car development from 2010 on.

 

I'm a very happy Nissan second generation Leaf owner for six years now and it, its two chargers and even its battery and inbuilt charging module will almost certainly outlive me, so I don't expect any large bills at all.

 

But e-cars are certainly not suitable for everyone. In fact they probably never will be in the way that ic cars have been, not just due to technical limitations but also due to the little realised ways that the market and society will be forced to change.

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I use E85 fuel and don't feel guilty about it.

Nissan have announced that they will have a solid state battery model on the road in 2028, and they have lead the way with lithium batteried e-car development from 2010 on.

 

I'm a very happy Nissan second generation Leaf owner for six years now and it, its two chargers and even its battery and inbuilt charging module will almost certainly outlive me, so I don't expect any large bills at all.

 

But e-cars are certainly not suitable for everyone. In fact they probably never will be in the way that ic cars have been, not just due to technical limitations but also due to the little realised ways that the market and society will be forced to change.

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The range on those Leaf cars has really improved hasn't it. One of my sons bought a second hand e. car. Maybe a citroen? Not sure. He likes it, but the range is pretty short - about 60 miles. It isn't a problem. He only uses it to get to work - about ten miles, and he can charge it free in the office car park. It leaves his missus with the other car (IC) to get to work and drop the kids. Nissan at Sunderland has had massive success. It is a big employer in the North East and is supposed to be pretty much the most efficient car plant in Europe.... I think that's right. Heard or saw it somewhere. The people who work there seem to like it - which is pretty new in the UK car business. I've talked to some of them.

I use E85 fuel and don't feel guilty about it.

 

No need to feel guilty at all. I certainly don't. I use my car when it is the most efficient or practical transport, and at other times, I ride motorbikes (100 mpg) or my bike. My car only does about 6K or 7k a year. The one I just got rid of averaged 62 mpg over the last year (diesel) and the new one which has only done 760 miles so far, has averaged 56mpg since new.

 

The UK emits 1% of current co2 emissions. If Putin nuked the whole place next week, China's ever increasing power hunger would take up our entire emissions budget by next year. China emits 12.7 billion tonnes of co2 a year, which is around 30% of the whole world's emissions. That Swedish troll girl needs to get after them and stay away from here.

The range on those Leaf cars has really improved hasn't it. One of my sons bought a second hand e. car. Maybe a citroen? Not sure. He likes it, but the range is pretty short - about 60 miles. It isn't a problem. He only uses it to get to work - about ten miles, and he can charge it free in the office car park.

 

Indeed it has. The first 2010 model with a 24 kWh battery was good for just over 70 miles (claimed 90). The revision with a 30 kWh battery three years later was good for over 90 miles (claimed 124). Both good for 89mph top speed and 11.2 seconds 0 to 62mph.

 

The increased efficiency second generation Leaf of 2018 had a 40kWh battery and big upgrades in range and performance with 40% BHP increase. WLTP range when new of 168 miles which I was able to achieve with 13 miles left over in the two reserves. Top speed sensibly still at 89mph but acceleration 7.9 seconds 0 to 62mph.

 

The Leaf e+ sporty model of 2019 on has a 63kWh battery, double the original Leaf's power at 210 BHP, WLTP range of 220 miles. Top speed 98mph and 0 to 62mph at 7.3 seconds.

 

The earliest Leafs are mostly still good for 50 miles and I know of three locally, two with with wives using them for school runs, shopping etc., one with a retired man who bought it from his son and now uses it locally and also for the occasional 120 mile round trip to visit his son. That means a top up on each leg of the journey.

 

All summer ranges, winter markedly lower.

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Don't buy cheap crap unbranded batteries or bikes or do stupid mods.

I need to watch the whole thing but it's late and I'm sleepy. So I'll leave that for tomorrow.

 

A related question for a newbie like me:

 

I'm pretty sure my Greenlance battery instructions' page says to charge the battery with it switched on (-). I think it's for extra security, since it says when the battery is 'on' it knows even more precisely not to overcharge it. (I need to give it another read, it's been a few weeks)

 

 

 

Is that how it should be and how most people charge their batteries? Intuition makes me think to charge it with the switch flipped to off (o).

charge it with the switch flipped to off

 

That's what it says on the instruction sheet my generic downtube battery arrived with.

That's what it says on the instruction sheet my generic downtube battery arrived with.

That's what I've been doing with mine, which is why I found it odd. I will re-read the Greenlance instruction sheet tomorrow to make sure I'm not mixing things up.

That's what I've been doing with mine, which is why I found it odd. I will re-read the Greenlance instruction sheet tomorrow to make sure I'm not mixing things up.

 

I've occasionally charged my battery while switched on by mistake, but for the past three years I've nearly always charged it when off. I checked cell group voltage a couple of months ago, and they were:

 

4.195V, 4.195V, 4.198V, 4.192V, 4.197V, 4.193V, 4.196V, 4.192V, 4.189V, 4.191V

I need to watch the whole thing but it's late and I'm sleepy. So I'll leave that for tomorrow.

 

A related question for a newbie like me:

 

I'm pretty sure my Greenlance battery instructions' page says to charge the battery with it switched on (-). I think it's for extra security, since it says when the battery is 'on' it knows even more precisely not to overcharge it. (I need to give it another read, it's been a few weeks)

Is that how it should be and how most people charge their batteries? Intuition makes me think to charge it with the switch flipped to off (o).

The general procedure to charge Chinese batteries is to put the jack in with the charger switched on because most have a permanently live charge socket and you need equal voltage when you connect, otherwise you get a spark, which can do some serious damage.

 

If your battery switch switches off the charging, that could be considered a bit safer, though it makes little difference as long as you connect with the charger switched on. With the charge socket switched off, you can connect with the charger switched on or off, then switch on the battery after connection to commence charging.

 

Personally, I'd always switch on both the battery and the charger before connecting, then there is no danger of a spark because there can't be any inrush current. When you connect with the battery charge socket switched off, then switch on after connection, there will still be an inrush, but you don't see it. Inrush is best avoided. It's caused when one of the devices has a large capacitor between the two wires. The capacitor charges instantly and draws a very high current, almost like a short circuit.

Edited March 19, 20242 yr by saneagle

Don't buy cheap crap unbranded batteries.

 

May I ask what battery do you have? I am looking for a battery for a while now and can't decide which to buy.

https://ebikebatteries.co.uk/

 

he isn't dead yet and if you want the best thats it but you got to pay for it and that spot welder is 25k

At least none of the past or present members on here have ever reported a fire.

 

 

 

At least none of the past or present members on here have ever reported a fire.

That's the point. You have to also consider that batteries from 10 years ago were nowhere near the quality of today's average cheap Chinese ones, and still we didn't have problems.

 

I would love to be an investigator for the fire service. I'd know what questions to ask, and I'm sure I'd get to the root of the problem quite quickly instead of all these university professors sitting in their labs theorising failure modes, then making irrelevant regulations that won't solve anything.

 

That's how I made all my money. I invented the simplest problem solving system. No maths was involved, no fancy diagrams and no convoluted theories. I called it "Find and Fix". When you have a problem, you go and look at it. You touch whatever and whoever is involved. At that point, there's a 90% chance that the cause of the problem and its solution are obvious. Sort it and go to the next.

Edited March 20, 20242 yr by saneagle

The risk factors are well-known though. Larger cells are less risky. The problem is how to maintain good gravimetric density with larger cells. Still, the risk is small compared to ordinary petrol oe diesel. The average car has 30-40 litres of petrol or diesel, or about 400kwh, much more than the average ev.

The risk factors are well-known though. Larger cells are less risky. The problem is how to maintain good gravimetric density with larger cells. Still, the risk is small compared to ordinary petrol oe diesel. The average car has 30-40 litres of petrol or diesel, or about 400kwh, much more than the average ev.

This is the sort of theorising that can send us in the wrong direction. For each battery that catches fire, there's a specific reason. Maybe I can explain better by way of example.

 

In 1996 the top range Vaillant boilers were failing on average three times during the warranty period. They had invited all the top consultants in to help solve the problem, but they made zero progress. If anything, it got worse. They actually had quite a good data system that gave codes for various defects found, and departments did a lot of data analysis.

 

My first action was to call a meeting with the chiefs of every department involved - quality, development, design, production, service and supply. I had a printout of all the defect codes and rates, and the diverter valve was at the top of the list, so I asked them what was going wrong with it. Instead of answers, I got opinions. I stopped the meeting very quickly and asked the guy from the quality department to bring 50 returned diverter valves to the meeting tomorrow and 8 sets of tools so that everybody could dismantle one and see what was wrong with it. These managers were not impressed, but the CEO had set me the task of telling him which ones he needed to fire, and they knew it.

 

At the next meeting, each participant was given a valve with its defect code, and the dismantling started. The first one had the code for leaking. It had a ball of expanded polystyrene from the packaging stuck between two sealing surfaces. No amount of theorising would ever have found that. The next and many more thereafter with the code for "not working" had a total gungey mess inside because somehow zinc plated screws instead of the prescribed stainless ones had been used to hold a copper spring. it caused massive corrosion. Within three meetings, we'd found about 20 common causes that accounted for about 95% of all faults. All had simple solutions, like putting a strong magnet on the shoot where the screws went in to the screwing robot. Worry about why some of the screws were the wrong material and where they came from later.

 

This way of doing things is not the German way. After the first meeting, all those guys hated me and were making snide remarks that they thought I couldn't understand, but we all became friends when the problems were solved and they kept their jobs. Vaillant is still in business and making boilers that don't break so easily.