How to access and remove the battery of this ebike?

[JamesG81]

The battery is setup for charge as show in the picture below. Just wanted to run this picture here to see if anyone sees anything that is not correct. I take responsibility for this no worries. Thanks.
https://docs.google.com/drawings/d/1L7YfPwrOs0R4bE2L0IL-N2FkO8WTpcrDZjmVnHM1sAU/edit?usp=sharing

I measured the voltages again. The new numbers are in the following picture.
https://docs.google.com/drawings/d/1dpWDc9h2wAsuJIgB4fFqe5sLvz7QoQ3ELrzjK3l0DUA/edit?usp=sharing

 

[JamesG81]

Just hooked up everything as was shown in the last post picture and connected to the electrical outlet outside the house. The light bulb came on dim for a few seconds then shut off and nothing after that. I think the original charger won't charge until it sees a certain voltage or something. Where do I go from here? Thanks.

 

[Voltron]

Not trying to be discouraging, but if you think about the layers of safety interfaces between the BMS, the charger, and the battery that are meant to keep you from doing what you're trying to do, maybe give in and recycle that thing?

 

[JamesG81]

I appreciate the emphasis on safety. It got me to research how such batteries can catch fire and even explode. This video shows how: https://youtu.be/0nrsoMsEMNU?t=396

In the video they have overcharged the battery by over 20 amps on purpose to cause an explosion.

If this battery is going to get charged, there will definitely be a fuse to prevent amperage from going over 2 amps. It will also be outside on concrete and in a strong fire proof box or bag. Any suggestion as to what kind of box or bag to use while charging this battery? Something that is cheap and effective. This is a pretty big battery about 21 inches long.

 

[Voltron]

They're overcharging it to get it to blow up of course, but that's the same kind of currents that will go thru a cell when the dendrites start piercing the separator layers and start shorting out the cell from inside...
Again, it's not about charging at low amps or about fuses... It won't be a dangerous object just during charging sessions.

 

[JamesG81]

I am open to be educated more about the safety subject of lithium batteries.

I like to know what is the difference between a new and an old battery like these that are very low in charge. Why the danger increases so drastically (it seems that is what you are implying) if a deeply discharged cell is recharged? And why this danger remains high even if the battery is recharged successfully the first time?

I watched several more online videos in regards to the dangers of lithium batteries. One of them showed that a discharged battery, apparently, is NOT very dangerous. Only when a battery has a lot of energy and is charged it can be dangerous. So my conclusion is that if a deeply discharged battery that is then charged is inherently more dangerous than a brand new battery, then the difference between these 2 batteries must be that one or more safety feature of the deeply discharged battery must have been defeated or bypassed when it lost its charge.

One of these safety features were mentioned on this thread earlier, which was that the metals in the electrolyte may not fully go back into suspension in the electrolyte and if these metals that have not gone back into full suspension bind together they can cause a short and overheat battery and cause the kind of fire and explosion that was shown in the online videos.

Are there any other safety features of a new battery that is different from a deeply discharged battery that is successfully recharged?

In another one of these online videos it was discussed that they are looking into using an all solid state electrolyte by removing all the flammable electrolyte from the cell and put down a ceramic layer capable of conducting lithium ions but not electrons. Thereby removing the possibility of internal short happening inside the electrolyte.

This is the link to this short but very informative video: https://youtu.be/D3GDdZkN6fg

From the video: "There are a lot of pieces and processes that go into a battery to make it work. If any of those processes goes wrong there is a chance for energy to be released, and the reason that happens really is because the electrolyte inside the battery is an organic solvent and that solvent is flammable. So if the battery can not vent you build up pressure and the electrolyte burns and then it explodes." Another section of the video: "In previous instances of batteries catching fire the cause has been bad welds. A lot of battery pieces are welded together and if you don't have a good weld then you develop resistance, resistance develops heat and heat leads to fire. Other times it has been due to contaminants during the building process. Contaminants were generated, a little bit of metal scraped inside of a machine and that contaminant fell into the cell and that caused a hard short between the anode and the cathode which then generated heat and so on and so forth."

So of utmost importance regarding safety of a battery is how well it was designed and manufactured and not metal suspension or precipitation inside its electrolyte. The cells of the battery that I am working on have Samsung written on them. Is there a way to verify that these are genuine Samsung cells?

So according to the above video the real reason for a battery to cause a fire or to explode is either manufacturing defect or lack of venting which can then lead to THE FLAMMABLE ELECTROLYTE to cause fire. In other words it is the flammability of the electrolytic that is the issue and not incomplete suspension of any metal particles inside of the electrolytic (correct this if you think this is the wrong conclusion). As an analogy think of a can of gasoline, it is inherently flammable and if you heat it up then it can catch fire and explode. So once the electrolyte is charged then it is like a can of gas because it is flammable. There is nothing in the video that talks about metal inside the electrolyte that goes from a state of suspension to a state of precipitation causing short but rather that unintended contaminants during manufacturing process causing such a short.

If what is in this video, put out by Michigan Engineering (I think it is the faculty of engineering of a university), is comprehensive in regards to fire and explosion hazards of these lithium batteries, that leads me to think that a used battery that has been proven to be defect free (no bad welds) and contaminant free (no manufacturing defects from factory) should be safer than a non tested fresh battery from factory especially a lower manufactured battery. The analogy of a used car engine and a new car engine comes to my mind: the used engine has gone through the break in period and is proven to be reliable but until the new engine has gone through the same type of break in period its reliability is an open question.

 

[Voltron]

It's these things... Dendrites. The time scale is 42 hours. They grow. How much they grew inside your battery is a guess.

 

[fechter]

From Battery University:

Do not boost lithium-based batteries back to life that have dwelled below 1.5V/cell for a week or longer. Copper shunts may have formed inside the cells that can lead to a partial or total electrical short. When recharging, such a cell might become unstable, causing excessive heat or show other anomalies

Dendrites are a different mechanism, but both dendrites and copper plating can result in an internal short which will cause rapid heating and a cascading thermal event (fire).

That said, I've revived some small batteries that were near zero and they behaved OK. The risk of fire may be elevated but hard to say exactly how much.

 

[E-HP]

I am open to be educated more about the safety subject of lithium batteries.

I suggest moving your charging and safety related questions over to the Battery Technology forum, now that the subject matter of your thread has moved beyond the question of removing your battery. You likely are seeing fewer responses or interest, relative to your charging questions, when they are embedded under your current subject line.

Note that the folks here are always looking after the safety of fellow forum members. If you noticed, everyone so far are providing you with advice to proceed cautiously, or not at all, and a lot of folks reading will want to provide that same advice, out of good conscience, to do what they can do to keep a fellow forum member from being hurt.

In other words, here, you are receiving advice and cautions from decades of real world experiences; the battery forum is the place to go to discuss the theory to prove it out, if that's what you need.

 

[JamesG81]

From Battery University

I have a low opinion of Battery University if it is the same site I was on sometime ago. Although I don't know much about it. I just remember looking up something and was led to that site and what was on there did not seem right. On the other hand, that video I posted of the Michigan Engineering appears to be of a research university that really knows their material. Of course I can't be sure of either.

Still your own experience and others here appear to suggest what I have already posted in the long post from yesterday and not the extreme and random battery fire/explosion that seems spectacular and frightening but no one has really experienced it. (Maybe someone has, if so it would be interesting to hear the details of how/why it happened from their point of view).

With that said, still of course, utmost caution as the possible (although at this point it seems improbable) consequences are life and property destruction.

 

[JamesG81]

I suggest moving your charging and safety related questions over to the Battery Technology forum

OK, it is done and the following link is that thread. Thanks.

https://endless-sphere.com/forums/viewtopic.php?f=14&t=102710

 

[JamesG81]

It's these things... Dendrites. The time scale is 42 hours. They grow. How much they grew inside your battery is a guess.

From this website: https://www.chemistryworld.com/news/fire-starting-battery-dendrites-go-with-the-flow/3008867.article

When a lithium–ion battery charges, lithium ions travel from the cathode to the anode; the ions flow the other way during discharge. At a lithium metal anode, lithium ions leave and return to the surface unevenly. This means that after several charging cycles, spiny projections called dendrites begin to grow from the electrode’s surface. As these lithium dendrites grow, they can pierce the membrane separator in the middle of the battery, touch the cathode and short circuit the cell. This can starts fires.

If the above site description of "dendrites" is correct, my understanding of the article is that dendrites are a byproduct of charge and discharge cycle and not about how low a particular battery charge has been reached. In other words dendrites form and have the potential of causing an internal short and this may increase depending on the number of charge/discharge cycles NOT on how low the level of charge has been reached. Putting it another way, dendrites DO NOT FORM ON THEIR OWN BUT ONLY DURING CHARGE/DISCHARGE CYCLES.