Fire at ebikes-sf

Thats a very reasonable point to raise for discussion.

Metallic lithium is quite reactive, so it was a major improvement when Lithium-Ion was tried, and found to be MUCH more stable. Its quite possible that the wax and graphite that Allcell is using in their so-called PCM block is potential fuel once a "tipping point" of heat is passed, but...I have to admit I am quite curious as to the actual recipe they are using, especially since they have a vested interest in mis-directing potential rivals who seek to copy it.
 
a concrete safe with a fan powered chimney is cheap. negative pressure means no smoke damage

sadly this is state of the art. lithium batteries will never be 100% safe even with solid state electrolyte. that is why almost 90% of federal funding goes toward lithium battery research. coors ceramtec has been sitting on solid state sulfur cell since the 70s when Ford had a car with 500 miles or range and a homopolar motor in the rear axle. look up the patents. the project was abandoned because the cells had to be heated and they were not practical. total BS. the coors and ford families are very well connected
 
Actually, Ceramatec's founding technology, in 1976, was a battery that used sodium-sulfur technology. Back then, in the early years, we were a small company and we struggled to get financial support. So we gave up in 1986. But we never gave up on the idea. We gave up on the effort to build the battery. We didn't give up on the idea that one day this battery could be the future of America.

really struggling right

Ceramatec is currently developing solid electrolyte batteries using ceramic membrane separators. Most of the work involves either a sodium metal anode with a sodium conductive ceramic membrane
 
extremely unsafe battery 1.5v max shock hazard



This invention relates to an electric vehicle drive train having a unipolar motor.

A unipolar or homopolar motor is a DC dynamoelectric machine that operates at high current and low voltage. It is a motor which has high efficiency and a high power-to-weight to volume ratio. Unipolar motors are described in U.S. Pat. Nos. 3,185,877 to A. Sears; 3,453,467 to L. M. Harvey; 3,916,235 to E. Massar; and 3,984,715 to D. Kullman et al. However, the preferred form of unipolar motor for use in connection with the present invention is described in commonly assigned patent application of the present inventor entitled, "Unipolar Dynamoelectric Machine with Variable Resistance Control" Ser. No. 863100, filed Dec. 1977.

The torque-producing characteristics of the unipolar machine described in the inventor's patent application identified in the preceding paragraph makes this machine particularly suitable for use as a traction motor in electric vehicle applications. However, because unipolar motors operate at low voltage and high current, for example, 10,000 amps, the DC source of electrical energy used to supply such motors must be located in proximity to the motors to prevent undue resistive electrical power losses. Moreover, the DC source of electrical energy used to supply the unipolar motor should have a high energy density.

Sodium-sulfur and other alkali metal batteries and DC sources developed by the assignee of the present invention, Ford Motor Company, are described in the following U.S. Pat. Nos. 3,404,035; 3,404,036; 3,413,150; 3,446,677; 3,468,709; 3,468,719; 3,475,220; 3,475,225; 3,488,271; 3,514,332; 3,535,163; 3,719,531; 3,811,943; 3,951,689; 3,966,492; 3,976,503; 3,980,496; 3,985,575; 3,985,576; and 4,049,889. The drive train of the invention also may be used with heat engines or thermoelectric generators or other low-voltage, high-current DC sources of electrical energy.

The sodium-sulfur batteries and heat engines mentioned above typically produce, for each cell in the case of the sodium-sulfur battery and sodium heat engine, a voltage of about 1.5 volts. Simplicity of construction of the heat engine or sodium-sulfur battery occurs if the various battery cells are connected in parallel rather than in series. If this is done, only a low voltage is produced but a very high current capability is provided. The high energy density capability of this DC source may be utilized to provide a practical energy source for an electric vehicle.

The low voltage produced by a parallel-connected battery as described above may be used to advantage by a unipolar motor. The present invention provides a drive train for an electric vehicle which takes advantage both of the unique properties of the unipolar dynamoelectric machine and the unique characteristics of the DC sources mentioned above.
 
The Invention Secrecy Act of 1951 made such patent secrecy permanent, though the order to suppress any invention must be renewed each year (except during periods of declared war or national emergency). Under this Act, defense agencies provide the PTO with a classified list of sensitive technologies in the form of the "Patent Security Category Review List" (PSCRL). The decision to classify new inventions under this act is made by "defense agencies" as defined by the President. Generally, these agencies include the Army, Navy, Air Force, National Security Agency (NSA), Department of Energy, and NASA, but even the Justice Department has played this role.

A secrecy order bars the award of a patent, orders that the invention be kept secret, restricts the filing of foreign patents, and specifies procedures to prevent disclosure of ideas contained in the application. The only way an inventor can avoid the risk of such imposed secrecy is to forgo patent protection.

By the end of fiscal year 1991, the number of patent secrecy orders stood at 6,193. Many such orders were imposed on individuals and organizations working without government support. This number shrank for each fiscal year thereafter, until 2002. Since 2002, the number of secrecy orders has grown, with 5,002 secrecy orders in effect at the end of fiscal year 2007.
 
I thought the cause of the fire was a hot charger,,,,, not the battery itself.
 
i have watched the output caps on chargers ignite like roman candles and spray sparks straight up out of the top of the can.

when there is a fully charged battery attached to the output then there can be a lot of power delivered to a short in the output stage of the charger back through the charging wire.

this would make the argument for using a large diode on the output of the charger to prevent the battery from adding to the short if there is a short and fire in the output caps. some chargers do have diodes on the output already. not the kingpan type.

what if the batteries could be stored and charged in a fire proof cabinet made with a series of individual cubbie holes like a bookshelf with dividers?

build it using the rigid cement backer board used for installing tile on the walls in the bathroom. it is cheap and can be obtained everywhere and can be cut without much problem to make the cabinet.

then create a thermal breaker type of module sensor to be placed on each battery being charged in the cabinet. a NO type switch that would close when the temp reached 40o C and by closing the circuit the breaker could turn on an alarm and begin a fire suppression sequence.

create some kinda state machine that could recognize which cubbie had the overtemp and be able to address the cubbie individually and begin spraying the inside of the cubbie with water to suppress the buildup of heat in that location while the alarm would be alerting the fire department through some fire alarm system and at the same time it would turn off all power to the chargers in this array.

if it could be built so that this individual cubbie would have a solenoid valve built in on the water spray system so that only the cubbie with the high temp that sets off the NO thermal switch would be the only cubbie that received the water spray.

this would allow the device to spray limited amounts of water to cool the fire and suppress as much as possible to prevent it from advancing to the other batteries until fire fighters arrived.

the coolant would not have to be installed as part of the domestic plumbing if there was something like a 5 gallon bucket for the water reservoir so that it could have a small submersible pump capable of delivering enuff volume of water to make the spray effective but not so much that the entire storage would be depleted in a few minutes until fire fighters arrived.
 
Thats a good point, but...I believe most blankets are flammable, and if you were on fire, and I had a blanket...I would immediately cover you with the blanket.

There must be some kind of wax-like substance that is not flammable (synthetic?) to alleviate such concerns. You have performed avaluable service by bringing this up. Even though I am unconcerned about the flammability of wax/graphite, others might be and they may avoid using this (even if it might be a huge benefit to them). For example, I never recommend LiPo to anyone, and yet I own LiPo (rarely used)...

dnmun (in the post below), for clarity...I was talking about if Chalo was on fire, I would cover him with a blanket.
 
actually covering a battery in thermal runaway with a blanket would make the battery get hotter faster and more risk of the entire pack going into thermal runaway. it is best to dunk the battery in water to carry the heat away immediately and if you can discharge the voltage off of the top of the pack it will reduce the overcharging that is causing the overheating of the battery which has provoked it to thermal runaway. the loss of heat into the water should stop the thermal runaway and give you time to cut the battery apart to remove the still hot cells.
 
In the USA conventional fire suppression systems in commercial buildings use water sprinklers. Water is piped to a sprinkler head with a thermal link that delivers water from the sprinkler above the link temperature rating. Fire alarm systems sense water flow and send alarm if sprinkler flow is detected. Perhaps in this case the building was not required to have such a system?
 
By the time the sprinkler is activated the fire is already of considerable size.

After the 1906 earthquake destroyed much of San Francisco due to the fire the regulations there have been considerable, and since the fire didn't destroy the adjacent shops, I would guess that the sprinkler system did function. It has been awhile since I was there, so I don't recall noticing sprinklers. The sprinklers are designed to flood the walls and prevent the fire from spreading.
 
Build a small canister of fire retardant into a battery pack. Pack catches fire, fire touches canister, and the canister bursts flooding the pack with fire retardant.
 
you don't wanna wait for it to burst into flames. i think of using a thermal circuit breaker or thermocouple so the alarm and water spray for cooling begins when the pack reaches 40oC.

you could put the sensor on a long enuff wire that the sensor could be placed right on top of the pack in the cubbie to monitor the temperature. maybe use tape or something similar to fix it to the pack. magnets won't work. silly putty would slow the thermal response because of the thermal mass of the silly putty.

fire extinguishers will not help much. you wanna cool the pack immediately to stop the thermal runaway. water has the best thermal mass and ability to wet the entire inner part of the battery immediately.
 
'hope he's back better than ever ASAP.

Yep, it's something the "industry" needs to better understand, learn and to perfect methods + tools to avoid these potentially deadly events.
 
justin_le said:
dnmun said:
not likely the fire started in the battery. they all have a BMS but a charger coulda spit fire out the fan when a cap blew up and caught something like paper on fire. usually they are from shorts imo.
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That's not impossible but it is a fairly wild conjecture given the circumstances. I've personally known over a dozen ebike shops or businesses now that have burnt down over the years, and it has always always been a lithium battery fire at fault, although I guess in many scenarios the damage is so bad that not a whole lot of forensics is possible to pinpoint the precise origin.

....BMS circuits can do a bit to prevent the one obvious cause of cells going pyro (overcharging), but they don't do anything for cells that seemingly at random burst into thermal runaway without any obviously external cause.
Click to expand...
Just wanted to capture those thoughts from a long-standing user/seller/reseller of the tech. I'm sure the pro vs anti lipo folks will never see eye-to-eye. I remain an ardent proponent of well made robust LiFePO4 cells of the A123 variety for most people most of the time. If weight matters enough to for some reason, because you're on a racing circuit or something, then the nitro of eBikes may be justified. And if you exercise all the precautions charging. However, the egregious arguments suggesting the two chemistries are the same with regards to thermal runaway and are equally safe is an extreme dis-service to the many many newbies coming to the forum looking for tips & advise. Get a kit, put it on and procure a safe LiFePO4 battery, the mainstay of the eBike industry. Then when that battery is on its last legs, you're experienced and know more, maybe... maybe then.

cells that seemingly at random burst into thermal runaway without any obviously external cause... because its internal, because of charging & over-charging and the chemistry has been altered. Only apparently random, but the science is well known, notwithstanding dnmum confusion profusion
 
I had the ebike president of currie tell me there was around 100 dedicated ebike stores in the country.

It seems that out of 100 we could easily come up with 5 that have had serious store ruining fires that we know about. 5 percent. Thats pretty bad. Almost all of those will be stores who deal with high power bikes with experimental lithium batteries...not commercial ebikes built by currie pedego etc which use fairly safe packs.

When you look back at old store fire threads its the same old thing... maybe it was a charger...maybe it was an angry ebike hating arsonist...and whats alarming is you cant suggetst lithium as probably culprit without getting reamed by lithium loving ebikers.... Cuz we all know lithium batteries are so "safe" and as long as we are careful nothing bad will happen to us.

I am really thankful for justins post to bring the issue out in the open and no one is going to shoot him down. Fire safety is really really a big issue and unfortunately it takes a fire to bring up the discussion....

No one can accuse Illia of deserving this because he didnt. He is as careful and knowlegable when it comes to lithium.


It kind of reminds me of the single engine pilot community, who all of us have lost at least one friend to flying but pilots still like to say flying planes is fairly safe, and most accidents are "pilot error". So as long as we are careful we are completely safe. The most dangerous recreational pilots are high hour long time pilots because they become complacent.

I am scared as hell of lithium after loosing a store to it...and view it as a constant threat since i have a lot of litiium around right now. I dont store it anywhere near my house. I have no fear of all cell or packs contained in metal ebike boxes, or panasonic ebike packs or wtv....its the pouches and hobby king stuff that really really scares me.

If anyone ever wants to here how i lost my store after 10 years I will finally post why....but at the time i wouldnt have dared or wanted too....i was dealing with my own pain and loss....and insurance companies.
 
the insurance companies are what worry me most. i am really fearful that they will introduce exclusions into the fire policies that will make landlords and businesses refuse access to any form of lithium battery. not just the lipo but all lithium will be included in their broad disclaimer. i think they did that to ZapPat when he lost his house and garage.

that is why i spend so much time trying to get people to use a BMS to protect from overcharging and to try to get people to read the literature on what causes the lipo to go into thermal runaway to begin with. but it seems most comfortable for everyone to retain the legacy opinions.
 
Just wondering if anyone has heard back from Ilia. I had emailed him buy I'm sure he's busy trying to sort things out.
 
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