Fuse-wire for individual cells, DIY Tesla style

I totally agree, but would they really risk battery safety for that?
How much imago damage does it do when a battery of a sudden brand catches fire?
Another reason for not using them could be space.
In a car, it's not really a problem if the pack is half an inch higher.
On a bike, they might try to make the battery as compact as possible.
And also, fuse wires are more fragile than solid nickel strip connections.
If the cells aren't fixed properly and protected against vibrations, a fuse wire could break due to metal fatigue.
Maybe the topic isn't about if "you should" or "should not" install individual cell fuses but more about how you can do it properly and reliable.
 
Yes, most bikers are just not even aware how dangerous their batteries are.

And those that know, very few would sacrifice extra cost or reduced density just to make them safer.

IMO.
 
spinningmagnets said:
Another thing you might ask is why most commercial e-bike batteries don't have individual cell fuses?

Fuses cost more, and the majority of customers are extremely price-sensitive.

I don't think our ebikes have a large enough parallel structure for individual cell fuses to provide an overall safety benefit, because they would make killing an entire parallel group more likely.
 
John in CR said:
I don't think our ebikes have a large enough parallel structure for individual cell fuses to provide an overall safety benefit, because they would make killing an entire parallel group more likely.
That is true if the ebike battery pack's parallel cells are wired inefficiently into "groups" instead of (for example) having 5 paralleled series strings (e.g. 14S5P) so that any one individual parallel cell's broken/melted fuse wire can't kill a parallel "group" as there's more than one path whether there are 4,5,6,7 or 8 paralleled series strings (e.g. 14S5P,14S6P,14S7P or 14S8P) when series strings are paralleled. See: http://endless-sphere.com/forums/download/file.php?id=98636 ... In the upper left diagram ("Worse current share") one can see why paralleling in "groups" is less efficient and also why if the one parallel cell's fuse wire closest to the series string melts it will prevent/kill the energy of the other good parallel cells in that group from reaching the series string. In the lower right diagram we see that with a group of 4P cells we need at least two series strings. Thus, if one of the parallel cell's fuse wire fails it won't kill the other parallel cells being there is only one parallel cell on each side of the series string.

Instead of thousands of cells (Tesla 3) DIY ebike battery packs with far fewer cells and therefore more susceptible when a few defective cells put more stress on other parallel cells. Like with many DIY Powerwalls there's only one parallel cell (not a "group") fuse wired to each side of the string with one one each side of the string (e.g. 24 per side or 48 total along a string). An ebike battery's string length is limited by available space and voltage (e.g. 14S). Not the case with a Powerwall or the available space and voltage requirement of Tesla 3 ... thus much less stress on other parallel cells when a few parallel cells become disfunctional among thousands of cells.

The new extended range Tesla 3 has 4,416 21700 lithium-ion cells. The battery is madeup of 96 “bricks" of 46 parallel-connected cells in a 96S46P arrangement. 46x96=4,416 suggesting one parallel cell on each side of a string and not in groups. The 96 Series bricks" are arranged into 4 long modules, 2 modules of 23 bricks and 2 modules of 25 bricks. The parallel cells are not really in "groups" as one might envision, instead if any one parallel cell fuse wired is melted (due to a defective parallel cell) it doesn't kill an entire "group" of parallel cells. Such a parallel "group" wiring scheme would be very inefficient if only one defective parallel cell's melted/broken fuse wire were to result in killing the available energy from other good parallel cells. Parallel "groups" of cells is NOT Tesla's wiring logic and for good reason where one disfunctional parallel cell can kill other good parallel cells along a string whether with the Tesla 3 18650 battery cells or with the 21700 battery cells ... https://electrek.co/wp-content/uploads/sites/3/2019/04/tesla-model-3-battery-pack-modules.jpg?quality=82&strip=all .
With [current consumer 18650 brand name cells] there is a PTC (Positive Temperature Coefficient) and a CID (Current Interrupt Device).
1. The resistance of a PTC will rise according to the temperature of the cell, this means the amount of current which can flow through the cell will become a function of the temperature effectively limiting and eventually cutting the cell off when it starts to overheat.
2. The CID is a mechanical device, effectively it's just a pressure release valve. When pressure builds up inside the battery the CID will pop out and thus mechanically cut the battery off" ... The PTC's are well enough equipped to catch a basic short without damaging the batteries. https://secondlifestorage.com/showthread.php?tid=981 (post #1)
So first of, I've been able to confirm that the Tesla cells do not have PTC's in them. ... Too be honest I think you're better of with a properly designed BMS which is equipped to handle short circuits and properly designed casings (space between cells) which won't allow for shorting individual cells or complete packs. ... https://secondlifestorage.com/showthread.php?tid=981 (post #6)
IMO, this does not prevent a potential FIRE due to human error from overcharging a battery pack having a $30 BMS. However, if this same battery pack had a $150 smart BMS (properly wired) could a battery pack FIRE be prevented? Can anyone verify that Tesla's 18650 cells Do Not have PTCs (because of increased production time & cost and that alone may be sufficient reason for explaining Tesla style fuse wiring even if there were never an accident causing FIRE ?

Whether or not it's worth the time and extra expense to use fuse wiring when using NEW BRAND Name cells is entirely up to the DIYer's preference and his specific application. If anything it makes sense to charge your battery packs in a protective enclosure or even outdoors if in doubt or not in doubt. Even moreso if the Chinese pack you bought was priced too reasonable with cells of questionable guality OR even a used DIY fuse wired pack you bought for a good price from a friend.
 
tenor.gif

 
John in CR said:
I don't think our ebikes have a large enough parallel structure for individual cell fuses to provide an overall safety benefit, because they would make killing an entire parallel group more likely. (not so fast CR)
CR=Controversial and Circumstantial Rhetoric (IMO) without proof. Very inefficient when parallel cells are in a "group" where one of the group's parallel cells can kill "an entire parallel group more likely". Parallel cells should not be fuse~wired in "groups" when one fuse~wired cell in that "group" can kill the other parallel fuse~wired cells in that "group". We can see in these four (3S?4P) diagrams why it's very inefficient to have a parallel "group" where one of the (fuse~wired) parallel cells can stress, kill or otherwise prevent power from the other two parallel cells in that group (upper left wiring diagram) ... http://endless-sphere.com/forums/download/file.php?id=98636 .

Interesting how a battery pack is defined by multiplying its number of Series cells by its number of Parallel cells to get the total number of cells in a battery pack. That in itself should be a clue as to the most efficient way to fuse~wire a S/P pack and why the the Tesla 96S46P battery of 4,416 cells (21700 cells) is fuse~wired so that one disfunctional parallel cell CAN'T kill other parallel cells when properly fuse~wired like Powerwalls and the Tesla 3 18650 and 21700 fuse~wired battery.

In this battery pack diagram(s) having twelve 18650 cells there are four different 3S?4P wiring diagrams shown ... http://endless-sphere.com/forums/download/file.php?id=98636. Generally referred to as a 3S4P pack because there are twelve cells with three 4P groups. Yet are any of the four (12 cell) diagrams truly wired as a 3S4P battery pack? The bottom right diagram is correctly wired for fuse~wiring. So should one of the parallel cells become disfunctional it won't immediately kill another parallel cell(s). The most efficient fuse~wiring logic with Powerwalls and the Tesla 3 18650 and 21700 battery is WITHOUT parallel "groups" where one parallel cell can "more likely" "kill an entire parallel group".

One shouldn't be so quick to assume there are parallel "groups" in which one parallel cell can "kill an entire parallel group" which is not the case with an efficient fuse~wired Powerwall or the Tesla3 18650 fuse~wired battery and the new extended range 21700 fuse~wired Tesla 3 battery. Thus one might surmise the most efficient fuse~wiring for the new extended range Tesla 3, 96S46P (96x46=4,416 cells) fuse~wired battery.

Efficient fuse~wiring logic should tell us that such a battery pack ... 1S with 3-4P "groups" (upper left diagram) ... http://endless-sphere.com/forums/download/file.php?id=98636 when fuse wired where one disfunctional "group" cell will stress, kill or otherwise limit voltage of the other parallel cells in that "group" to the lone Series string. Unfortunately someone is too hungup on parallel cells always being in a "group" which isn't the case with efficient fuse-wired Powerwalls or the efficient fuse~wired Tesla battery. Also correctly/efficiently wired ebike packs don't allow/permit just one parallel cell to "more likely kill other parallel cells".
 
If you look at a single parallel group and short circuit one of the cells, you need enough current from the other cells to blow the fuse. Otherwise the fuse won't blow and all the cells in that group will be discharge to zero, which ruins the cells. In a Tesla or large powerwall, if one cell shorts, the other cells in the group will more than likely have enough current to blow a fuse link. In a bike pack where you may only have a few cells in a group, chances are much better that the fuse wire won't blow.

Another consideration is that cells rarely short completely. Even smashing one with a hammer might give you a low resistance short but still much higher than the cell's internal resistance. In this case, the fuse wire won't blow and the damaged cell will get extremely hot and most likely start burning. I've seen a number of cells fail with a high resistance "short" that just behaves like very high self-discharge rate. Not even enough to get hot, but enough to drain the cell down to the damage point overnight.
 
fechter said:
If you look at a single parallel group and short circuit one of the cells, you need enough current from the other cells to blow the fuse.
From the following closeup photo provided by spinningmagnets we can see that the Tesla parallel cells are not in "groups" so if one cell were to become disfunctional to the point of melting a fuse~wire it would NOT KILL other cells along the Series string nor would other parallel cells KILL one or more of the other parallel cells (withstanding a major ACCIDENT). For example with a 96S42P parallel cell arrangement it's most likely staggered like with the 18650 Tesla battery. So, with a 96S42P battery we can envision that there are 14 Parallel cells fuse~wired on each side of the 96 Series strings and another staggered 14 fuse~wired parallel cells under the center of each Series string (14+14+14-42) ... https://endless-sphere.com/forums/download/file.php?id=201254. Doubt Elon Musk or his engineers would consider this staggered single parallel cell arrangement to be a "group" of parallel cells. Not all parallel cells have to be in a "group" as john once thought until explained that parallel cells can also be seen as being more of a parallel "string" than a "group" of parallel cells.
fechter said:
Another consideration is that cells rarely short completely. Even smashing one with a hammer might give you a low resistance short but still much higher than the cell's internal resistance. In this case, the fuse wire won't blow and the damaged cell will get extremely hot and most likely start burning. I've seen a number of cells fail with a high resistance "short" that just behaves like very high self-discharge rate. Not even enough to get hot, but enough to drain the cell down to the damage point overnight.
We know that one reason fuse~wires are used with DIY powerwalls is because of used salvaged cells and because of increased number of parallel cells along a lengthy Series string. However, in the event of a disfunctional cell melting a fuse~wire it will NOT result in a chain reaction KILLING other parallel cells along the Series chain. NOT all parallel cells are in "groups" in fact it's more efficient for a fuse-wired Powerwall or Tesla battery that the parallel cells are NOT in parallel "groups".

If just makes good sense to have just one fuse~wired parallel cell on each side of a Series string as with a Powerwall or a Tesla battery (with another fuse~wired parallel cell under the center of the Series string) ... https://endless-sphere.com/forums/download/file.php?id=201254 . Having a "group" of parallel cells where possibly it's "more likely" one of the parallel cells in a "group" could "KILL an entire parallel group" is counter-productive.
John in CR said:
I don't think our ebikes have a large enough parallel structure for individual cell fuses to provide an overall safety benefit, because they would make killing an entire parallel group more likely.
The parallel cell arrangemenet in Powerwalls and a Tesla 3 battery are NOT in parallel "groups". For example a 14S4P DIY ebike pack may have 4 paralleled Series strings (14S4P) for performance. If fuse~wired there would be one cell on each side (7 on each side) of the paralleled Series string. With 7 cells fuse~wired onto each side of the 4 Series strings (14x4=56 cells) and NOT fuse~wired in parallel "groups" in which case it would "make killing an entire parallel "group" more likely".
 
I call any individual cells in parallel a "parallel group" regardless of the series parallel physical connections (as long as they are connected in parallel at the cell level), and those groups are connected in series "strings" even if the series connections are at every cell.

I still don't see any arguments supporting cell level fusing for our ebikes. The parallel structure isn't broad enough to prevent a dead cell from killing the others in it's parallel group with or without fuses on the cells, and in a crash you are easily separated from the bike with no possibility of being stuck inside a steel cage with a damaged battery attached where cell level fusing may be able to slow the release of energy. Plus our voltages are so much lower that "events" are very different than what can happen in seconds with a car size pack.
 
spinningmagnets said:
If the paralleled sub-pack is a 5P and one cell-fuse melts, that string will suddenly become a 4P sub-pack, but...the pack will still run, with each of the other four cells having 20% more amps pulled from them. I have a few ideas about how to flag a blown cell-fuse right away, but...the important thing is for an internally shorted cell to stop thermal-runaway immediately, so the entire pack doesn't go up in flames.
Purposedly enlarged and emboldened 5P string to make a point that it was not a typo or error by spinningmagnets when referring to fuse~wired parallel cells as a "string" instead of as a parallel "group".
spinningmagnets said:
I think a useful visualization exercise, is to see a 5P string in your mind, and then suddenly swap one of the cells for a fat copper wire (representing an internally shorted cell, from a wreck, or an overheat situation). All of those cells will now flow from one side to the other, so that fat copper wire is flowing FULL 5P cell amps, with no BMS to limit the max amps.
Now, visualize that fat copper wire being connected to the positive bus side by a short and thin wire. Once that thin wire melts?...the unregulated flow of all the 5 cells in that P-string is stopped. At best you'd have to replace that single bad cell...at worst you'd have to replace all five cells in that P-string (which I would recommend). But, the best reason to do this is...the pack doesn't go up in flames...
Again, spinningmagnets has reason to refer to a run of fuse~wired parallel cells as a "string" instead of as a parallel "group".
spinningmagnets said:
I have been guilty of using "string" and also "group" when referring to cells, whether they are in parallel or series. I'm still on the lookout for a definitive reference, after which I will follow the proper electrical engineering term.
I see nothing wrong with spinningmagnets use of "string" when it comes to a run of fuse~wired parallel cells in a Tesla battery. If a DIY ebike pack were fused~wired then would it not necessitate a run of fuse~wired parallel cells on each side of a Series "string" like with a Powerwall? Isn't that one bottom-line reason why we see so few, if any, fuse~wired DIY ebike packs? Especially with a triangular shaped pack?

Spinningmagnets (IMO) is not out-of-line when referring to a run of fuse~wired parallel cells along a Series string as also a "string". Another use of a parallel "string" is when a 14s4p battery has 4 paralleled 14S strings for optimum ebike performance.
 
Mark, please stop claiming to speak for me.

Cells in parallel form a group.

Cells in series form a string.

Groups in series form a string.

That is all there is.

99% of of what you write on these layout issues - completely ignoring the fusing and failure mode issues - is literally incomprehensible to me, and I just can't engage anymore.

So, again, please just leave me out of it!
 
I apologize if my past posts on this subject have muddied the waters as far as the proper term to use.

It appears as though the endless sphere members have a majority of us that want to call paralleled cells a group, and seriesed cells a string. I have no dog in this fight, and I'm fine with either way, I only hope to spread ideas so each builder can benefit from the work of those who have come before them.

I am not saying that individual cell-fuses are a great idea for me, or even a good idea for anyone. This thread is simply here to have all the available information and pics about this type of pack-building, so that each one of us has all of the info and opinions available, and that it is all in one place.
 
group vs string is just a convention for ease of quick communication.

doesnt' matter which you use.

the point of a conventional terminology, regrdless of how it comes about, is so taht the terms don't have to be reexplained in detail every time they are used.

to clarify this by example:


if more (most) people already use a specific way of using a term, and others come along and choose to use the same term differently, then unless they specifically explain that they are indeed using that term in a different way and how they are using that term, every single time they use it, then all of those used to the more common way of using the term will have a large chance of misunderstanding what is being talked about.

so if you were to say you use 5 groups of three strings of cells, then those already using group for parallel and string for series would "know" you meant a pack of 5 parallel cells by three series cells, though they wont' know specifically how you've wired it.

but if you don't mean that, and instead mean 5 series cells by three parallel cells, you would have ot explain every time you say it that you mean that, if the convention is to use group for parallel and string for series. otherwise those used to the convention will have to assume you mean 5 parallel by three series and communication fails and problems figuring out what's going on ensue.




another example would be if you use a to mean amp-hours instead of ah. its' not teh convention to do this, but vendors that sell but have no clue about batteries often do it. or use w intead of wh for watthours. they mean completely different things.

the convention is to use a for amps, and ah for amp-hours, and w for watts and wh for watt-hours. becuase a is a current and ah is a capacity, and w is a power amount and wh is a capacity.

so when vendors list their batteries as being 52v12a, then since they dont' explain what that means to them, every time they list it, then anyone using the normal convention will assume they are only capable of outputting a maximum of 12a, and have no way of knowing what their capacity is. but they also have to wonder if the seller really means 12ah, not 12a...but they can't know by reading the listing because the convention is not being used.

if instead the vendor simply uses teh convention, then 52v12ah means they are 12ah capacity, and one can guess based on common cell types that it can do at least 24a, possibly a lot more. but at least one definitely knows they're really taling about the capacity and not the max current rating. ;)



so you can use any word or term to mean whatever you want it to mean, but if you use it differently without detailing the rest of your usage, those that have learned to read it one way will have to assume they should still do so, and will misunderstand what you say.

choosing to follow the most-used convention of how a word or term is used results in the least amount of misunderstandings.
 
Back to the cell level fusing. Can someone please outline a set of conditions where cell level fusing could help an ebike sized pack, where just a master fuse wouldn't work just as well, because I can't think of one?
 
a master fuse doesn't do what cell level fusing would do, so neither replaces the other.

that is regardless of wehther cell level fusing woudl work in an ebike sized pack or not (which i don't know)

cell fusing is intended to protect individual cells from overcurrent, either inflow or outflow,

inflow if a cell internally fails in a way that then draws current from other cells constnatly so that cell will heat up (potentially enough for a fire if there are enoguh other sufficiently-charged cells n paralel with it).

outflow to protect the other cells from draining into that failed cell and overdischarging and being damaged


master fusing is intended to protect boht

the system wiring and other compoents in case a short occurs downstream of the fuse, so current stops flowing to the short htru other things,

and the entire battery itself from being drained dead by such a short




while cell level fuses might blow and protect the system and pack in a situation with sufficient short current at the main pack output when there is no master fuse, a master fuse will not blow and protect cells if there is an internal pack failure.
 
I was playing with copper strands where I would take a 4.2v and a 3.5v battery and parallel it. it would turn red and disappear, a 20 amp 25r.
when it comes to an ebike battery I think you need too many amps flowing through the string. I always see people fusing to a bus bar. the only thing ive been thinking about doing is fusing the p-connections according to what the charger puts in as amps for what the bms needs to burn off, 1 or 2 amps? I really don't know

ive had 2 pack failures, 1 failure was a completely dead cell 0 volts and the indication I had was my battery range lost 2.5ah but battery worked, the other failure was my battery in a backpack I was using for range, 20km from home I plugged it in and it was dead I lost an entire parallel group mid pack. start pedalling a DD hub home

my thinking is if 1 cell in the entire pack dies and the parallel fuse blows, I only lose 1 string of cells/2.5 ah and ill know somethings wrong just from looking at the CA, when im riding I know what the readings should be as far as volts/ah/distance. atleast I can slow down still get home using pedal assist on a DD hub. or is that wrong?
 
John in CR said:
I call any individual cells in parallel a "parallel group" regardless of the series parallel physical connections (as long as they are connected in parallel at the cell level), and those groups are connected in series "strings" even if the series connections are at every cell.
electrek.com agrees with you
John in CR said:
I still don't see any arguments supporting cell level fusing for our ebikes.
AGREE! However, there may be a rare exception (???) such as with forcefed's 18S10P ebike pack with 4 different brand name salvaged cells. All of the 180 cells are rated between 2600mAh to 2650mAh capacity when new, but have different amp ratings ...

Sanyo FM 5A 2600mAh rating when new, Panasonic CG 10A 2600mAh rating when new, LG B4 3.75A 2600mAh rating when new, Sanyo ZT 5.2A 2650mAh rating when new.

The bigger question is whether or not his 18S10P pack is even worth the effort to incorporate fuse~wiring. He has divided it into 3 smaller 6S10P packs for balance charging and then reconnect them for 18S10P use ... https://endless-sphere.com/forums/viewtopic.php?f=14&t=104161 .

Cell fuse~wiring makes more sense with a Powerwall of good salvaged cells of fairly equal amp and capacity rating that can be closely monitored with sufficient charging, BMS and fusing protection.
__________________________

Previously posted an image link ... https://electrek.co/wp-content/uploads/sites/3/2017/08/tesla-model-3-battery-pack-modules.jpg ... of Tesla's (Aug. 24th 2017 article) 100 kWh pack, which was then the top-of-the-line for Model S and Model X, having 16 modules for a total of 8,256 (18650 cells) per pack ... https://ww.electrek.co/2017/08/24/tesla-model-3-exclusive-battery-pack-architecture/# .

The first photo is of the previous fuse~wired Tesla battery followed by a diagram of a newer version for Model S and Model X battery ...
p100d-module-1920-e1485293673350 (1).jpg
View attachment 1
FWIW, electrek agrees with john when it comes to its 96S46P battery that "consists of 4416 cells in groups of 46 cells per brick." but do we know for sure that the 46P cells are fuse~wired in this newer (2017) battery shown in the above diagram ?

Is it possible that this Tesla battery for the Tesla 3 and Tesla Model X is NOT fuse-wired? What about the NEW 21700 battery?

tesla-model-3-battery-pack-3.jpg
1. Charge port connector 2. Fast charge contactor assembly 3. Coolant line to PCS 4. PCS – Power Conversion System 5. HVC – High Voltage Controller 6. Low voltage connector to HVC from the vehicle 7. 12V output from PCS 8. Positive HV power switch 9. Coolant line to PCS 10. HV connector to cabin heater and compressor 11. Cabin heater, compressor and PCS DC output fuse 12. HV connector to rear drive unit 13. HV pyro fuse 15. HV connector to front drive unit 16. Negative HV power switch 17. Connector for 3 phase AC charging.

This above diagram is for the 18650 Tesla 3 and Model X battery shown in that August 24th 2017 article. Couldn't find a diagram or photo of new 21700 Tesla battery with 4,416 cells (96S46P). Is it possible the new 2170 doesn't make use parallel cell fuse~wiring ?
https://ww.electrek.co/2019/04/17/tesla-model-s-x-refresh-upgrade/
 
For me, the ideal is choosing cells with enough Ah capacity so that

A. each cell can be monitored / protected, tested and serviced / balanced /replaced as a unique individual,

with no grouping at the lowest level,

and,

B. the pack is composed of no more than two strings in parallel, and even that not ideal, only for mission-critical use cases when redundancy is required

the ideal being just one string.

The reason I'd consider fusible links is when the above is just not possible, forced to use these tiny cylindricals due to space constraints, odd pack shape etc as with ebikes.

The idea being, within the 1S groups at the lowest level, a cell failure gets automatically isolated, so the rest of that group's

Ah capacity gets cut proportionally, unavoidable

but maintains most of its voltage level and the rig keeps on truckin'

Now if the fusible link is sized to open **just above** the highest ampacity that connection requires,

I "would think" most catastrophic cell failure events would isolate that cell.

But I dunno really, more data / IRL testing needed.

The other part, is getting notification that the link has opened, if not real-time (which of course is the ideal),

then as soon as the pack gets put on whatever balancer / charger / performance-checker/monitor gear I've put in place for that rig.
 
I have stopped.

Just asking that he refrain from publicly trying to correlate his understanding of what he thinks I mean, with what he is interpreting from elsewhere.
 
john61ct said:
I have stopped.
Just asking that he refrain from publicly trying to correlate his understanding of what he thinks I mean, with what he is interpreting from elsewhere.
I have also stopped and have also asked that he STOP with purposely misinterpreting my previous posts with disinformation and misinformation with double spaced lines and broken sentence structure. FWIW, my mention of electratech using "groups" when referring to the newer 2017 Tesla battery was meant as a compliment to john. But as usual john can find fault and discredit me Even john's very first comment calling me a "creep" about my LI-ion chemisty post on docware's DCIR thread which was an unnecessary flamming reply to which john has yet to apologize . Then later john agreed that the type of chemistry does have some relevance to docware's 18650 DCIR tests of several different name brands. It was john that should have received a WARNING for his flamming comment.
spinningmagnets said:
It sounds like you guys will never agree on this. Everyone has stated their opinion several times. Why keep arguing?
Hopefully, my reply will encourage either john or spinningmagnets to definitely say whether that newer 2017 Tesla 3 battery is fuse-wired. If no one knows for sure whether or not it (2017 Tesla 3 above battery photo) is fuse~wired ... then this thread by Ron is based on the previous older fuse-wired battery and if so then why this thread if newer Tesla 3 battery are no longer fuse~wired.

This thread has been going since 2017 and yet does anyone to know for sure if that above photo of the newer Tesla 3 battery makes use of parallel cell wire~fusing? When spinningmagnets started this thread in 2017, he showed a photo of the previous older Tesla battery with parallel cell fuse~wiring runs as that older battery was then outlived its life and available for salvaging any useful cells.

Now it's 2020 and does anyone yet know for certain that that newer 2017 Tesla 3 battery (see above photo) was also fuse~wired as was its predecessor? Does anyone know if any of those newer 2017 Tesla 3 batteries have yet gone beyond the 120K-150K warranty and now available for salvaging any useful 18650 cells. IMO, most everyone just assumed that spinningmagnets was sure that the newer 2017 Tesla 3 battery made use of fuse~wiring like the older one shown at the beginning of this 2017 thread. However, from john's latest post i get the impression that fuse~wiring a DIY ebike pack is not such a great idea to which spinning magnets agreed. Maybe, Elon Musk decided that fuse-wires weren't as much of an advantage on the newer 2017 Tesla 3 battery?

So i assumed (like everyone else) that spinningmagnets was sure that the newer 2017 Tesla 3 battery in the above photo still used fuse~wiring. Otherwise, why would spinningmagnets have started this DIY Tesla style fuse~wire thread in 2017 ... with the possible intent being that fuse-wiring be at least considered for larger ebike DIY battery packs.

Question: Is there now any reason (after 2 years of replies on this thread) to assume that newer 2017 Tesla 3 battery (above photo) no longer has its parallel cell runs in a string as was the case with its predecessor, but instead its parallel cells (2017 Tesla 3 battery) are now arranged in groups?
 
Some builders are interested in individual cell fusing, and some are not. To each their own. I only started this thread so any accumulated info about this will be all in one place.

If you are arguing against cell-fusing, then dont cell-fuse when you build a pack.
 
And I'm sincerely not flamming or disparaging here - I honestly cannot answer your questions, because I cannot understand your wording.

In fact your phrasing leads me to believe that you still do not yet full understand how serial / parallel layout issues actually work, in any of the various packs discussed here.

Maybe if you find a way to **draw** how you think it works, we can find a common ground for communication using standard terminology.
 
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