Dr Wu, I'd like to thank you so much

@BillyWu

2 жыл бұрын

Thanks for watching

Excellent presentation Dr. Wu

@BillyWu

2 ай бұрын

Thanks!

Thank you Billy, your vocabulary and articulation skills are spectacular, keep up the great work.

@BillyWu

2 жыл бұрын

Thanks!

I see your accurate ; but it must be pointed out to people - batteries do not need to be abused to catch fire. Recently a ship containing brand new just produced EVs had brand new never abused batteries catch fire burning the entire ship up. It is critical for buyers or potential buyers to realize there is a risk of fire with EV batteries even if you do not abuse them at all. This is due to dendrites; deposits that can build inside the battery which can short basically at random causing a fire; once one battery catches fire it spread to thousands of other batteries and there is really nothing that can stop that fire.

@BillyWu

4 ай бұрын

Good point and agreed that there are other causes of failure in a battery also. As the quality control of battery production increases and also improved safety designs are implemented hopefully this will decrease the likelihood of these events, but right now there is still a risk to be managed

Amazing presentation. I love that the entire presentation is super clear, detailed and to the point. Love it.

@BillyWu

5 ай бұрын

Thanks. Glad it was clear and helpful

Another excellent presentation. Thanks again Billy. Best wishes John

@BillyWu

Жыл бұрын

Many thanks

Really love the deatailed explanation provided in this video.

@BillyWu

8 ай бұрын

Glad to hear it helped

🔋 Thanks Billy

Very impressive and simplified over-view on the battery related fire.✌

@BillyWu

2 жыл бұрын

Thanks

Thank you very much for your clean explanation !

@BillyWu

2 жыл бұрын

Glad it was helpful!

@sportshungers

2 жыл бұрын

@@BillyWu yeah it was very helpful to me that why battery fire occurred.

Thank you very much. Very clear.

@BillyWu

2 жыл бұрын

Thanks

This is an excellent over-view of battery fires, without too much confusing chemistry for some people. In LFP (lithium iron phosphate) cells, the oxygen atom is attached to the phosphorus atom; whereas, in the other battery cell forms, the oxygen atom is attached to a metal atom. Is this the main reason an LFP cell is more resistant to mechanical and thermal abuse? What can firefighters do to abate a battery fire, since the cell's chemistry provides its own oxygen for a fire? Would a liquidized gas (CO2, nitrogen, hydrogen) dampen the fire?

@BillyWu

2 жыл бұрын

Thanks. Yes, that's correct. Generally speaking, the oxygen is more tightly bound in LFP than a chemistry such as LCO meaning potential thermal hazard is a bit lower. Also, LFP has a more stable atomic structure (olivine) than LCO (layered) which means over-discharge is a bit less detrimental. Still challenging to stop battery fires. There are a few solutions such as fire blankets and vermiculite based extinguishers being proposed but I think we still need better approaches.

perfect explanation of the events ❤

@BillyWu

10 ай бұрын

Thanks. Glad to hear it was useful

Thank you for such an informative video

@BillyWu

Жыл бұрын

Glad it was helpful!

Thank you professor, I gone your papers all are great work.

@BillyWu

2 жыл бұрын

Thanks

Thanks!

@BillyWu

2 жыл бұрын

Glad it was helpful/interesting

Thx for a very thorough & understandably presented video. I've been looking for this info for weeks, but YT didn't show it to me. I understand now that I prevented a runaway when I touched a (1 cell) vape power source. It was getting very hot. I partly unscrewed the base to stop it. I CAN imagine the toxicity of hydrofluoric acid (HF) as a gas. OMG

@BillyWu

Жыл бұрын

Glad to hear it was useful. Yes, when these batteries fail things can get pretty bad and the more we can share information about this, the better.

Great work, Billy. Is there any reference for the SEI decomposition at 70C ?

@BillyWu

2 жыл бұрын

Great question. The various additives can modify the exact number but reference such as Wang et al 2006 Journal of the Electrochemical Society 153 A329 "Thermal Behavior of Lithiated Graphite with Electrolyte in Lithium-Ion Batteries" gives data on this. iopscience.iop.org/article/10.1149/1.2139955

definetly one of the best teaching videos about Li - Ion Batteries i have seen so far .. (but i still have to watch it at half speed ) Nice video ..., but what is adding to the confusion is that different sources (youtube videos) mention different temperatures ... 60 degree Celsius a batterie starts degrading ... (e-Scooter reached 60 degrees Celsius during normal , modest travelling for 10KM, ambient temperature was about 10-15 degrees Celsius ) 70 degree , separator starts decomposing ... 100 degree Celsius , Elektolyte with Anode reaction .. 130 vs.160 degree Celsius C seperator starts melting ...

@BillyWu

Жыл бұрын

Thanks and good points. The exact numbers can change depending on the specific materials used. For example different electrolytes and additives can change the thermal stability and there are different types of separator material being using. So, this video hopefully gives some starting points to consider but the exact values can vary depending on the specific materials used.

Millions of Lithium Ion batteries are disposed of every day. Many, if not most, people don't give a second thought to just throwing them out with their trash. The lack of safety precautions is likely causing injury to the disposal collectors and environmental impacts in the landfills where the trash is dumped. Procedures must be developed and enforced for the disposal of these batteries.

@BillyWu

Жыл бұрын

Definitely a hot topic!

@edwardk3

Жыл бұрын

Did you have any known cases of injured garbage men you can share? Or are you making that up from speculation?

Over discharge also caused expansion in one of my batteries

@BillyWu

Жыл бұрын

Sorry to hear. Probably worth disposing of this safely

Good sir, in this video, you means that the BMS is very important to install in our battery pack? Thank you ✌️✌️✌️

@BillyWu

2 жыл бұрын

Yeah, A good BMS is essential to make sure a battery pack stays within operating limits to avoid failure

This video is very helpful, very nice work. I think that lithium batteries are a bit dangerous, they are almost everywhere. I was thinking that it would be possible to safely store it in large quantities and quickly put it out if there was a fire.

@BillyWu

Жыл бұрын

Thanks. The technology is getting safer but quality control and technology is key. Since the market is increasing so rapidly not all cells have the same quality control and therefore we need to be careful and also plan for the worse case. There are increasing numbers of products focusing on addressing this issue

@bendaistvan79

Жыл бұрын

Biggest problem when a large amount burns or when in a parking garage.

@BillyWu

Жыл бұрын

@@bendaistvan79 Definitely. Hazards go up significantly with size of system

@exsollertan7366

Жыл бұрын

@@BillyWu In your description of the various stages of thermal abuse, at 300 deg C, the lithium Oxide disassociates and oxygen is released, thereby feeding the fire. For LFP batteries, does a similar event occur?

@BillyWu

Жыл бұрын

@@exsollertan7366 Good question, in one of the later slides I show the onset temperatures of different materials. LFP is generally safer since it releases less heat and less violently but can also decompose.

Most data sheets specify 2.5V and 4.2V as the discharge and charge limits. Are these open circuit voltages, or terminal voltages? Is the degradation of the cell cause by terminal voltage or (in some sense) the open circuit voltage?

@BillyWu

2 жыл бұрын

Ideally you don't want the terminal voltage to go beyond these levels, but in reality its the internal battery voltage which is important though in some cases it can be difficult to exactly measure it.

fyi dendrite that are formed CANNOT short ciurcuit the battery

How much safer is the LFP battery as some EVs have this type of battery? I have seen LFP penetrative tests on KZread that seem to be a lot less dramatic.

@BillyWu

4 ай бұрын

The exact numbers depend on the design of the battery, but LFP in general releases about half the heat of NMC and ~a quarter of the heat of NCA cells with a higher decomposition temperature as shown in slide 11. Safety characteristics ultimately depend on a number of things such as nail penetration characteristics, heat release when over heated/over charged etc.

Nice explanation - but still have to question the technology - is it really green, safe and even futuristic? I give low marks on all accounts.

@BillyWu

6 ай бұрын

Thanks and good question. Sustainability of batteries could still be improved with some elements of the materials extraction and manufacturing being a bit carbon intensive. Safety is still an issue but there are new battery types which aim to improve this (i.e. solid-state batteries). Overall both elements are improving.

hello is it safe to leave a lithium battery in my hot car during summer? it gets up to 140f in my car (60c).

@BillyWu

2 жыл бұрын

Probably best not to. There's been a number of battery safety incidents in India related to high ambient temperatures. Where possible remove them or at least put them in shaded areas

This is a fire and not an explosion. Get your facts right

@brettgregory7799

3 ай бұрын

Perhaps you'd like to get your manners right! (and explain your point of view)

@MikeEnergy_

2 ай бұрын

What happens when gas pressure builds up within the battery cell?