Does Capacity of a "typical" 18650 or 21700 cell (e.g. Samsung 40T) increase during the first few cycles?

[Scooter22kph]

I've read different opinions, some say there is some kind of chemical agent inside a battery from the factory, which is supposed to increase shelf-life, which needs to break down or dissappear first during the first few cycles. Some say no difference.

I've searched through the forum and looked at cycle tests, but couldn't find any graphs showing the capacity for the first few cycles, only cycle 1, cycle 100, cycle 200 etc.

Does capacity increase? Slightly? Or not at all?

 

[docw009]

I've also heard this modern folklore that says a battery needs to be charged a couple of times before it reaches full capacity,
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I doubt it, but, I could be wrong. At the individual cell level, I have some new Eve 18650 cells that have never been charged. Unless someone says it's a waste of time, I can pop them in my Littokala charger amd do some science, subject to the limitations of the Liitokala, .

In ebike batteries, users may indeed think see more range on the second charge, A lot of that is variable. Uncontrolled conditions like wiind and hills. Pedal assist. Maybe they didn't charge it fully the first time. A lot of ebike batteries don't have good balance circuits, so the first discharge tends to equalize them so they can attain more charge, I have an ebike battery load tester too. I never kept the records, but I don't recall seeing a new battery get better with time,

 

[jonyjoe303]

One thing I noticed from building packs, when I tested the individual cells I discharge them at 1 amp, when the pack was put together it was a 25ah pack. During testing of the completed pack with a dc wattmeter until the bms disconnected, the dc wattmeter reported 30ah was used.
If the pack is not used in high amp discharge situations, it might seem the capacity is higher.

 

[docw009]

I ran two Eve 2500 mah cells thru my Littokala tester 7 times. They were brand new, never spot welded or used. These are the discharge from 4.20V to 2.80V @ 500ma. No real difference.

	Slot 1		Slot 2
	Discharge		Discharge Charge
1​	2531​	0​	2534​
2​	2566​	1.38%​	2533​	-0.04%​
3​	2554​	0.91%​	2519​	-0.59%​
4​	2562​	1.22%​	2536​	0.08%​
5​	2537​	0.24%​	2530​	-0.16%​
6​	2556​	0.99%​	2518​	-0.63%​
7​	2552​	0.83%​	2528​	-0.24%​

 

[BlueSwordM]

I've read different opinions, some say there is some kind of chemical agent inside a battery from the factory, which is supposed to increase shelf-life, which needs to break down or dissappear first during the first few cycles. Some say no difference.

I've searched through the forum and looked at cycle tests, but couldn't find any graphs showing the capacity for the first few cycles, only cycle 1, cycle 100, cycle 200 etc.

Does capacity increase? Slightly? Or not at all?

With how current battery manufacturing works, no.

There's almost always first cycle capacity losses when charged/discharged at the factory, so it wouldn't really change much.

There are ways for cell capacity to increase within the first few cycles through the use of pre-lithiation techniques, but these aren't widely available yet.