Lipo vs Lion

[john61ct]

Because this forum is **the** canonical source worldwide for high quality, user-sourced thus objective battery information

including for uses other than propulsion.

Not saying allowing those lower-C use cases to interfere with the primary purpose of most discussions (I'm really trying guys)

just to **also** keep them in mind.

Also there are even propulsion use cases where super high density (of either type) is not the highest priority and bigger packs can result in "lower" C-rates like 2-5C say are the norm

cargo bikes, surface vehicle modeling and boats come to mind.

Finally it is useful to isolate out when looking at longevity specifically the usually-deadly effect high C-rate factor, from the more universal factors like QC consistency, chemistry purity, physical build quality etc.

 

[DogDipstick]

1. LiPo, for hobby packs only.


and 4. EV packs specifically, which can be composed from either #2 or #3, but let's not confuse with #1


_______

All other thing being equal,
Clearly, for use cases requiring even occasional high C-rates, say over 1C continuous, then you must choose higher-power batteries in order to get any kind of longevity, even if 300 cycles is considered "long life".

MY EV CELLS ARE LIPO! I understand your attempt at erenaming all the definitions of cells, but, if its got a liquid, its a Lion and if its got a polymer its a Lipo. End story. Lipo DOES NOT mean hobby grade exclusively, I konw you want it to. If you dont want to stick to norms, you can use " hobby grade" lipo vs "EV grade lipo"... but EV is not restricted to either.

Make up whatever nomenclature you wish on a whim. I know they are true lithium polymer, and do not base the chemistry, or cell composition, on the form factor ( cyl, pouch)... Its what is in them, not what they go in or what you want to call them.

EV lipo took me farther than hobby lipo, here in this forum, and would think it best we keep with the norm... ? Instead of mislead, for our own simplicity.

 

[DogDipstick]

"afaict"

I been saying this whole thread they are lipo. LIPOLIPOLIPO. Nothing to do with the pouch or the cylinder. So no, as far as you can tell (afayct), will you call a lipo a lipo when it is a lipo? Or are we renaming the design ( for everybody?) in hopes to help one newb with a budget understand what the thing HK sells is commonly known as?

Here is a accurate description. : https://en.wikipedia.org/wiki/Lithium_polymer_battery

See? doesnt say "hobby grade pack" or " hk lipo" anywhere.

 

[DogDipstick]

"afaict"

I been saying this whole thread they are lipo. LIPOLIPOLIPO. Nothing to do with the pouch or the cylinder. So no, as far as you can tell (afayct), will you call a lipo a lipo when it is a lipo? Or are we renaming the design ( for everybody?) in hopes to help one newb with a budget understand what the thing HK sells is commonly known as?

Here is a accurate description. : https://en.wikipedia.org/wiki/Lithium_polymer_battery

See? doesnt say "hobby grade pack" or " hk lipo" anywhere.

also, I challenge your definition of "Prismatic" as inaccurate too. They can be jellly rolled too, I have seen it. They are not just "pouches".. so saying that would spread (more) disinformation for it is not accurate, . Defining an inaccurate definition is a useless practice... absolutly useless.

Summary

With the pouch cell, the manufacturer is attempting to simplify cell manufacturing by replicating the packaging of food. Each format has pros and cons as summarized below.

Cylindrical cell has high specific energy, good mechanical stability and lends itself to automated manufacturing. Cell design allows added safety features that are not possible with other formats (see BU-304b: Making Lithium-ion Safe); it cycles well, offers a long calendar life and is low cost, but it has less than ideal packaging density. The cylindrical cell is commonly used for portable applications.

Prismatic cell are encased in aluminum or steel for stability. Jelly-rolled or stacked, the cell is space-efficient but can be costlier to manufacture than the cylindrical cell. Modern prismatic cells are used in the electric powertrain and energy storage systems.

Pouch cell uses laminated architecture in a bag. It is light and cost-effective but exposure to humidity and high temperature can shorten life. Adding a light stack pressure prolongs longevity by preventing delamination. Swelling of 8–10 percent over 500 cycles must be considered with some cell designs. Large cells work best with light loading and moderate charge times. The pouch cell is growing in popularity and serves similar applications to the prismatic cell.

Prismatic cells are contained in a rectangular can. The electrodes are either stacked or in the form of a flattened spiral. They are usually designed to have a very thin profile for use in small electronic devices such as mobile phones. Prismatic cells provide better space utilization at the expense of slightly higher manufacturing costs, lower energy density and more vulnerability to swelling, but these are minor effects which don't constitute a major disadvantage.

 

[john61ct]

Fine. . .

EV LiPo vs hobby LiPo

can live with that, certainly seem to be worth distinguishing between the two

But for prismatics, I'm sticking to the "hard cased with thread or post terminators"

As opposed to the pouch format that requires building a case, figuring out how to connect wiring to tabs etc.

As to their internal construction, don't really think relevant to most.

Really looking to cover those choices commonly sold as new to consumers, not **every** possibility out there.

Obviously all five categories are just cells, nothing like "engineered packaged systems" as from Victron, EPS, (Lithionics/Ocean Planet or MasterVolt

nor those (inferior) "drop-ins", nor

portable powerpacks that might include various ports and circuitry/ports for voltage converters, charging, solar, inverters etc as well as limited BMS

all outside the scope here.

 

[john61ct]

Here's a wrinkle

not all EV packs are Lipo

I assume Tesla isn't the only one?

 

[DogDipstick]

Fine. . .



But for prismatics, I'm sticking to the "hard cased with thread or post terminators"



all outside the scope here.

... your "opinion " does not make it " fact". It only makes for the vernacular, albeit yours. Not necessarily everybody.... A clear definition is imperative when giving advice to people whom may not know the accuracy of your statement and rely on the integrity of said knowledge.

Yes, you can see the traits, generalize on said ( visible ) traits, but I base on definition, not generalized conjecture. By definition, prismatic can be jelly rolled.

As to their internal construction, don't really think relevant to most.

.. Absolutely relevant, and the definition of such, is relevant. The construction ( internal and external) is what makes it prismatic....Not one or the other, but both. I understand your generalization.

5. Prismatics, have pouches internally but hard-cased with posts or bolt terminations

I challenge this definition you put forth based on my layman's knowledge of the definition of "prismatic cell". I may or may not be wrong. I am a layman, certainly in this field without real schooling on the subject, I'll admit.

adjective
adjective: prismatic

relating to or having the form of a prism or prisms.
"a prismatic structure"

prism
/ˈprizəm/

noun
noun: prism; plural noun: prisms

Geometry
a solid geometric figure whose two end faces are similar, equal, and parallel rectilinear figures, and whose sides are parallelograms.

Metal or plastic cased with terminals for space saving and convenience. Those traits I agree upon.

Relevance is negligible, yes... to those that which the knowledge does not matter, but I think this matters, here in the context of....

A definition of a cell type..... the act of defining, or of making something definite, distinct, or clear: .

 

[john61ct]

So for "prismatic" I'll use:

hard rectangular cased, with posts or threaded terminals

By definition, prismatic can be jelly rolled

What do you mean by that?

Link please to examples, spec sheets whatever.

All the ones I know about, look somewhat like this

 

[john61ct]

Show me any concrete reference to the Multistar line being optimized

No one is using "optimized" as a general "good quality" word, it only makes sense as "optimized for. . ."

When tweaking a given chemistry and physical design for high energy density, you sacrifice power, C-rate, and v/v.

When striving for max longevity, you're usually increasing sticker price per Ah.

Of course TCO amortized cost-per-cycle or per-year may end up cheaper but that's a different factor than acquisition cost.

As has been stated, many report very satisfactory usage with the Multistar line, likely at lower C-rates.

If there are "better" ones for **their** usage, of course you can pay a lot more per Ah for high-power packs,

but really the question is, in the **same** price category,

higher Ah energy density or maybe lasting longer

suitable for usage with no need for those higher C-rates that **you** consider "normal".

 

[DogDipstick]

"afaict"


Here is a accurate description. : https://en.wikipedia.org/wiki/Lithium_polymer_battery

also, I challenge your definition of "Prismatic" as inaccurate too. They can be jellly rolled too, I have seen it. They are not just "pouches".. so saying that would spread (more) disinformation for it is not accurate, . Defining an inaccurate definition is a useless practice... absolutly useless.

Summary

With the pouch cell, the manufacturer is attempting to simplify cell manufacturing by replicating the packaging of food. Each format has pros and cons as summarized below.

Cylindrical cell has high specific energy, good mechanical stability and lends itself to automated manufacturing. Cell design allows added safety features that are not possible with other formats (see BU-304b: Making Lithium-ion Safe); it cycles well, offers a long calendar life and is low cost, but it has less than ideal packaging density. The cylindrical cell is commonly used for portable applications.

Prismatic cell are encased in aluminum or steel for stability. Jelly-rolled or stacked, the cell is space-efficient but can be costlier to manufacture than the cylindrical cell. Modern prismatic cells are used in the electric powertrain and energy storage systems.

Pouch cell uses laminated architecture in a bag. It is light and cost-effective but exposure to humidity and high temperature can shorten life. Adding a light stack pressure prolongs longevity by preventing delamination. Swelling of 8–10 percent over 500 cycles must be considered with some cell designs. Large cells work best with light loading and moderate charge times. The pouch cell is growing in popularity and serves similar applications to the prismatic cell.
https://batteryuniversity.com/learn/article/types_of_battery_cells

Prismatic cells are contained in a rectangular can. The electrodes are either stacked or in the form of a flattened spiral. They are usually designed to have a very thin profile for use in small electronic devices such as mobile phones. Prismatic cells provide better space utilization at the expense of slightly higher manufacturing costs, lower energy density and more vulnerability to swelling, but these are minor effects which don't constitute a major disadvantage.

https://www.epectec.com/batteries/prismatic-pouch-packs.html

There.
Sources quoted.

I could find more but I think this will suffice. Merits being, the case has nothing to do with the cell and can be either pouch OR jellyroll, which you (incorrectly?) stated " all prismatic are pouches".. I do not implicitly ( without qualification: absolutely) think they are.

I think the "optimization " is just a way for HK to sell more junk lipos that cannot hack it. The differences are negligible except in the power delivery, where the power destroys batteries, and a surplus of capacity would just get used up... in application.

I undersand the merits of "optimization" but I do not think that HK truly does anything special and honestly just pumps out second rated cells in hopes of selling more. The diffence inenergy density is negligible here, the power density is not. IMO.

I was under the impression that you lump ALL prismatic with " pouches" when they are not all "pouches".. Yes they are cased. That definition stands, but earlier you reference prismatic as having pouches, that which universally they DO NOT. Your initial assertation was

"5. Prismatics, have pouches internally but hard-cased with posts or bolt terminations"

...

No. I do not think this fits the (correct) definition. You then ascertained the "case" ideal, but not the " only have pouches in them" assertation.

 

[john61ct]

I was asking for links to specific mainstream **products** on the market

suited for the various uses discussed in these forums

with this "jelly roll" format.

If it's a rare edge case, never mind.

Don't go to any trouble, just idle curiosity afaic not relevant.

In theory, even if a prismatic cell was secretly composed of cylindrical cans internally, I wouldn't care, test it on its merits.

 

[DogDipstick]

I'll find some blatantly obvious pictures of the roll for ya, and then try to link some pics of an opened prismatic with said rolls in place. Not to hard.

Will update... but yeah.... cut & stacked.. vs rolled ... I mean the rolled... LION is diffent from the cut and stacked LIPO. That is what we are asking? The difference between lipos and lions? Can a lipo be rolled, or stacked? It is the electrolyte that makes a diffence ( wuts a polymer anyway lol.. ).. to my knowledge. The electrolyte.

 

[john61ct]

No, I think I get it, at least for current purposes.

Personally I haven't seen any prismatics of interest other than LTO and LFP, and I know those chemistries aren't of much interest here compared to the other formats.

I challenge your definition of "Prismatic" as inaccurate

And since then I have modified it, thanks for the feedback.

 

[DogDipstick]

Personally I haven't seen any prismatics of interest other than LTO and LFP, and I know those chemistries aren't of much interest here compared to the other formats.
.............Me neither, but I have read about them: Got a 105Ah to test... It is LiFePo...

THere are low power application prismatic ( storage) with a liquid elecrtolyte and high power application prismatic ( EV traction battery use) . Many chemistries and forms ( shape)

Prismatic cells are contained in a rectangular can. The electrodes are either stacked or in the form of a flattened spiral. They are usually designed to have a very thin profile for use in small electronic devices such as mobile phones. Prismatic cells provide better space utilisation at the expense of slightly higher manufacturing costs, lower energy density and more vulnerability to swelling, but these are minor effects which don't constitute a major disadvantage.

This example from GS-Melcotec has a steel can with spiral wound electrodes and a liquid electrolyte.



Ex. low power: https://www.mpoweruk.com/specifications/prismatic_cells.pdf

Ex. high power: https://www.mpoweruk.com/specifications/power_cells.pdf

Yes, random example, but I think the difference is there. IDK. I do wish an industry professional would weigh in and let us have the experienced truth, as to what is what. I know its been gone over 100+ times already..

 

[John in CR]

AFAIK prismatics are not pouches and pouches are not prismatics. They are just close cousins. Nissan Leaf modules look prismatic, but are pouch cells in a can. I would venture to guess that most electric car companies use prismatic cells, such as the 26ah Panasonic prismatic that has dimensions even useful in larger packs for ebikes. I like the threaded post version of that cell used by Ford, but it does come with other ways cells connect together that save a bit of space over the threaded post version I have.

While there may be some exceptions like some of the large plastic encased LFP prismatic cells, all prismatic and pouch cells require some kind of compression plates against the flat face of the cells for best cycle life. That includes RC lipo that have a plastic heat shrink to create some compression, because they benefit from having a more rigid surface at both ends of a stack of cells compressing them more than just the shrink and better preserving a flat shape for the enclosed pouches. They are commonly shipped and stored without compression, but as the cells expand and contract during cycle use the flat face of both pouch and prismatic cells will bulge and greatly affect performance without adequate compression.

Only cylindrical cells are able to maintain their original shape over the long term, so they don't require compression. Their biggest downfall is wasted space, with generally small format cells requiring a multitude of cell connections (potential points of failure) being a close second.

 

[john61ct]

While there may be some exceptions like some of the large plastic encased LFP prismatic cells, all prismatic and pouch cells require some kind of compression plates against the flat face of the cells for best cycle life.

Those aren't exceptions, CALB, GBS Winston / Thundersky / Sinopoly, all should have plates & strapping to prevent swelling.

I believe even some of the aluminum-cased ones too, and some do not isolate the case from the anode, more complications, why I prefer plastic casing.

 

[John in CR]

While there may be some exceptions like some of the large plastic encased LFP prismatic cells, all prismatic and pouch cells require some kind of compression plates against the flat face of the cells for best cycle life.

Those aren't exceptions, CALB, GBS Winston / Thundersky / Sinopoly, all should have plates & strapping to prevent swelling.

I believe even some of the aluminum-cased ones too, and some do not isolate the case from the anode, more complications, why I prefer plastic casing.

That's good to know. Regarding cell insulation, though I'm sure there's something better that's cheap, I've just used a double layer of packing tape wrapped around each cell to insulate them from each other. Then on those prismatic Panasonics that have only about a 4"x 6" face, I use epoxy infused plywood as my compression end plates and quite a few layers of stretched electrical tape to achieve a nice even compression of the string, followed by a few layers 3M duct tape to lock the compression in. One end of my steel battery racks are bolt on for a tight fit to lock in the compression for the long term. I've also done welded racks for a snug fit at a low SOC, but battery strings can get hard to remove years down the line after the contraction and expansion of many cycles stretches the duct tape a bit.

I find that a relatively small investment of time upfront to overcome small complications is well worth the effort for a battery pack you don't plan to touch again for 8-10 years or more.

 

[flat tire]

So is multistar still the go-to option for high energy density hobby cells or is there better? That's never been answered.

 

[john61ct]

aluminium plate can often be found cheap at a local scrapyard

There's a **lot** of pressure from a say 1200Ah column, plywood just won't contain it.

 

[john61ct]

I'd be wary in a mobile context of rubbing friction wearing breaks into a thin layer of plastic

Just about any stiff non conductive sheet material will do as a separator.

Some worry about the temp differential, cells in the center getting a bit warmer creating imbalances over time.

Some vendors sell top/bottom caps that create a gap between their aluminum prismatics, so I presume those casings won't allow swelling.

Or they leave enough "slack space" internally to account for the 5% or so swelling that can occur from "normal" gentle C-rate, not too deep DoD% usage.

The makers' usual customers have engineers on staff, who presumably get more canonical info when buying multiple container-loads of product, but them that really know never seem to show up in DIY consumer forums 8-(

 

[Hillhater]

Up to a few years ago, we used to have a member on here that worked inside 123 and had all the data on pouch cell compression tests.
Maybe if you search back enough on “A123 compression” you might turn up a few nuggets !
PS: the Leaf pouches are not under compression inside those aluminium cans !

 

[amberwolf]

Up to a few years ago, we used to have a member on here that worked inside 123 and had all the data on pouch cell compression tests.

wb9k
https://endless-sphere.com/forums/search.php?keywords=&terms=all&author=wb9k&sc=1&sf=all&sr=posts&sk=t&sd=d&st=0&ch=300&t=0&submit=Search

 

[Ianhill]

So is multistar still the go-to option for high energy density hobby cells or is there better? That's never been answered.

And maybe someone can teach the really angry guy the difference between quote and edit and also let him know that multiple posts are no good when a single post will do.

This thread is to long winded for me to dedicate any decent answer but for hobbygrade Lipo turnigy high capacity 20ah cells are whats being pushes after Multistars demise but that will no doubt be lost in translation amongst massive power banks being displayed.

Got to agree the shrink wrap cells have is not adequate to stack and using some alu plates to place a few newtons on the cells face to keep everything in place won't go a miss but clearly dont think they are capacitors and crank the shit out of it heres the 16s pack I done out of them on a scooter build bout 4 years ago I think maybe more.

 

[John in CR]

PS: the Leaf pouches are not under compression inside those aluminium cans !

The top of their cans are designed to be like large flat springs, and inside the can is a thick somewhat rigid plastic sheet to distribute the compression force evenly across the face of the first cell with adhesive bonding all of the cells together. The rack of modules has rigid steel plates at both ends with compression applied evenly via the long threaded rods at the corners, and there are steel brackets and tubes to help spread the force evenly to all of the modules in the rack and ensure none of the cans crumple at the edges.

No the cans don't compress the cells, but the mounting rack certainly does. One of the early Leaf cell testers even demonstrated a pretty big capacity difference between Leaf cells in free air and cells under compression. On my full rack of 24 modules, the threaded rod assembly compressed the length of the stack by about 2.5" compared to simply stacked with gravity providing the only compression.

 

[John in CR]

Up to a few years ago, we used to have a member on here that worked inside 123 and had all the data on pouch cell compression tests.
Maybe if you search back enough on “A123 compression” you might turn up a few nuggets !
PS: the Leaf pouches are not under compression inside those aluminium cans !

If I recall correctly the recommended compressive force recommended by A123 on the AMP20 cells was 4psi. That doesn't sound like much, but with a cell face of about 50sqin, that's like a 200lb weight compressing a stack of cells.