Bench Test Results: Molicel P45B - 50A 4500mAh 21700

Batteries and Chargers Rechargeable Batteries
61

I don’t think I’d worry about A vs B unless you’re needing to marry sets of cells in high power lights. Molicell thus far seems to be holding the manufacturing quality pretty high, nearly on par with the major OEMs, so the minor differences in voltage/capacity/spread on grade B cells aren’t a huge deal. Fair pricing is another irritating matter, though. If there’s another application where those slight differences might matter in choosing the B-grade Molicell over another cell, just try to make that call with the best info/testing available. Obviously we’d all prefer the best but sometimes it’s not such a problem, imho.

Good to see Molicell rise up and keep cranking out quality cells over the last few years! I don’t know where they stand in relation to the big guys or the major China cell manufacturers, but they seem to be holding their own and are more accessible for the masses.

62

"more accessible to the masses"!? Are you talking about an element for the price of which you can buy two 40-T? Or maybe it's twice as good, or Molicel a more advanced brand, than Samsung?

63

I would imagine the difference between A and B cells has to do with —- Over/Under Resistance and Capacity — Maybe Production date —— I doubt anyone using these cells in a flashlight would be able to tell the difference — Who knows we might all be getting B cells with other brands —- Just watch out for the C, D and F cells, I’m not sure if they grade in vowels —— JK

I know most of the A cells go to Bulk battery companies for battery packs

64

Maybe there isn’t that much of a difference. Then again, I would wager that the Grade B cells are less consistent in terms of quality and performance than a grade A Cell would be.

I certainly wouldn’t pay $9.99 for the rewrapped Epoch P45B or $13.99 for a grade B Molicell P45B cell. That is what 18650 battery is selling them for.

Guaranteed when Jon gets the grade A cells, whenever that may be, they will be a much much more reasonable price, genuine and the best.

Personally, I like the psychological advantage of having the best, unless the difference in price is outrageous.

65

One last thing before I get on with my lunch and my day.

It was nice that the salesman from 18650 battery store admitted that the P45B are B quality cells.

However, if I never asked him or told him what Jon said, he never would have told me and obviously I would have had no way of knowing.

My point being they’re not advertised as B cells. To me that’s deceptive and the prices are outrageous for both the Epoch rewrap and the Molicell P45B cell itself.

Jon definitely has more integrity and vows not to sell them until their grade A.

66

I learned something which is always good. I found the interesting article of the difference between Grade A and Grade B cells.

https://evreporter.com/lithium-ion-cells-a-grade-vs-b-grade/#:~:text=B%20grade%20cells%20have%20a,batteries%20which%20experience%20sudden%20death.

He mentions the biggest danger is with EV’s.Because the Grade B are not the same quality and can be susceptible to Thermal Runaway, dendrite formation, short circuits and more.

In addition, since they are not the same quality it is not advisable to use them for fast charging and high power discharge.

In any event, I would never use one of them in my flashlight because I want the best and I don’t need any more unnecessary dangers.

67

How do you know they are Grade A cells —- Jon says they are —- I’m sure that’s what he’s being told on his end —- From what I’ve learned (especially with cells ) there’s lots of deception —— Unless the wrapper or cell itself is marked a certain way, you can never be sure

68

Nothing is certain in life.

He deals directly with
Molicell.

I guess he trusts them and I trust him.

How do we know we’ll be alive tomorrow?!

EDIT: The simplest and best answer.

Sometimes you just have to have FAITH. :wink:

Dinner is served. Salmon and Buffalo meat for Nikko.

Salmon and yams for myself.

69

No, I mean that they openly established authorized dealerships and didn’t try to wall that off. They made a big effort during the initial shortages of cells as the pandemic ramped up so that distributors and people across the world might be able to buy what they need (to their own benefit of course). And they aren’t trying to scare the world way with “do not use” labeling like we’re seeing on the big major wraps these days. Pricing (here in the US anyway, which is what I pay attention to since this is where I live) fluctuated a lot, but that’s primarily the distributors/retailers and for the most part now it’s nearly back to where it was (seems to be about a 15–20 price increase that isn’t going away, but it’s not the rampant abusive “commodity pricing” that we witnessed for awhile).

70

Good article…just skimmed it but I’ll read it fully later. Probably important for us all to remember that hardly any flashlights come anywhere near what is asked of cells in EV scenarios. The current demands, the floating charge, etc. etc. (and it might be argued that the risks are lower as well, in the way we use and charge our cells vs. a vehicle). The whole industry revolves around mobility now.

If you can chat with Jon sometime, it’d be interesting if he could share what specifics he knows about Grade A vs Grade B on the Molicells (factory supplied?)……and other brands as well, since they very well may be different in their grading/specs.

71

After reading that article I also thought of getting Jon’s perspective. Great minds think alike. Although with age mine is weakening a bit!

He is an engineer. I think it’s mechanical but I can’t remember for sure.

I sent him an email. He always responds pretty fast.

Probably not till next year! Tuesday or Wednesday most likely.

Have a happy and safe new year.

72

^

I also asked Jon to chime in, he is a member who posts every once in awhile.

I rather hear from him than me paraphrasing it.

73

Looking forward to the P45B Grade A! Please share when they are available! Will definitely buy a bunch.

74

For any not in the know, grades mainly refer to consistency.

When making a large battery pack, consistency is king over everything else, especially as higher consistency = better cycle life.

75

Consistency is important but my opinion there’s a lot more to it than that. Like safety.

I suggest reading that link I provided in my post number 66.

The guy explains the big differences between Grade A and grade B.

I think he knows a lot more than both of us.

76

It all depends what are Molicel criterias, might be different from what is said in the article, unless the grade A/B thing is an industry standard, which is doutbful, and if your guy can get those criterias from Molicel directly then that would be very helpful.

77

And a happy new year to you!

I didn’t know Jon was a member here. It’d be great to have him speak on this. On that article, I think it was more of a generic treatise but it did have some good info, especially for peeps that may not be at all aware of the cell industry. I forget about those power wall users and what their cell needs are. I never gave it too much thought in the past but it would be nice to learn some of the tech particulars on this subject and solid inside/industry info is always welcomed. I browsed some of the older Samsung datasheets I have, and I suppose it’s easy to surmise what doesn’t make grade A from the information there, but knowing more about B could be helpful.

78

BTW, I think I might have realized something interesting about one of the ways Molicel could have improved the energy density slightly and greatly improve power density without sacrificing anything else(outside of higher initial costs because of R&D investments).

Basically, as cells have been getting denser and denser in terms of energy density, other components have been getting lighter, smaller and of course, thinner as not to make the gains smaller.

One of the often overlooked components that have been getting the cut are the current collectors that are actually welded to the cells internally: as you go up in capacity within the same form factor, they get smaller and smaller.

Furthermore, this problem isn’t absent in high power density cells: even with thicker current collectors, having large current collector rollsa adds unecessary ohmic resistance. While this isn’t too much of a problem in a small cell form factor(18650) and relatively tame currents, this becomes a big problem as you increase thickness and want to increase current density further.

This is why Tesla adopted a tabless design for their 46800 cell: to make the thickness resistance penalty almost negligible, allowing for similar or better power density than a smaller cell design.

Hence, I believe(until we see a full cell teardown) that one of the ways Molicel improved power density is simply by using a multi-tab design, which would still greatly lower ohmic losses from the conductors while not necessitating a whole tabless electrode design, requiring a large manufacturing tooling change.

Now, there are obviously other changes at play, but I believe this is one of the bigger changes.

79

Hope everybody had a great holiday. Figured I’d jump in here and clarify some things.

One important thing I want to clarify is that I never said anyone else’s cells were definitely grade B. I just said that NPE was telling me grade A wasn’t available at the time, and my other contacts told me the same, so we didn’t have access to grade A. Maybe someone else had gotten a small amount through some unknown connection, something like that is always possible although it did seem unlikely. We feel very strongly that we always want to sell grade A (other than very rare cases where we explicitly call it out as lower grade), and they seemed to be coming in grade A soon, so we didn’t pursue getting any lower grade ones.

Now it does seem grade A is available in Taiwan and has been for at least a short period of time, in very limited quantities and at high prices. It will be some time before we have them (probably late February) just because it takes a long time to ship from Taiwan without spending insane amounts on shipping (and we don’t want to have to pass on that cost). So as always I can’t say what competitors are doing but it’s much more likely that others might have grade A now or soon, compared to when Cochise334ever talked to me before.

For the price complaints, you do have to keep in mind that P45B was originally developed for the supercar brands to make electric vehicles with - it is a “cost is no object” cell. It’s not intended to replace the P42A. So the P42A will continue to be much more widely used. But some customers like supercars and military and the like will want a cell like P45B that is substantially more expensive for only a small improvement in performance.

Still, our price will not be quite as high as what the current market is charging.

Anyway, onto the grade B questions. The article posted in this thread is a bit sensationalistic about the risks of grade B, but partially that’s because it’s talking about EVs. When you have more mismatched cells it is a much bigger problem in a large pack than it is for something like a flashlight with one or a couple cells. It also depends a lot on what exactly is meant by grade B as I’ll talk about more.

I don’t have concrete info on exactly what grade B is in each case. First of all grade B is not a standardized term. There are two categories of cells that might be referred to as grade B. 1st category is when it meets the public specification but not well enough to be used with their most demanding customers, who usually have their own requirements that exceed the standard specification. 2nd category is cells that don’t meet the published spec (these guys usually will have something like grade A1 and grade A2 or something to describe different levels of meeting the spec).

For the 1st category, it could be they are not matched as well to each other, or it could be that they have more self discharge than usual but still reasonable, or maybe capacity is less than the best possible. These are just examples of what it could be, it could be any performance parameter that comes out less than ideal. I have heard the self discharge one is a common reason for molicels to be rejected as lower grade but that’s just unverified info I heard and not official info - but that could be a potential guess here.

The second category is obviously the much scarier one. But even then it may just barely not meet something and not be a big deal when used in very small applications.

It’s always tough to tell with lower grade products, and only the company buying the cells can get details on why exactly they’re grade B. That’s part of why we don’t deal in this stuff.

Anyway, hope that helps clear things up slightly. Wish it was possible to clear up more.

80

Yes, the main difference is more anode tabs. You got it.