is charging with CC/CV bad?

[hank]

Qnovo | WHY IS CHARGING WITH CCCV BAD?

It’s from a company that’s using a new charging algorithm meant to protect battery life.
Mostly about cellphones and such devices that are on continuously, have to raise their power to reach signal towers, and get recharged fast —- so the discussion is not specific to flashlight use

When the voltage reaches a predefined limit, often 4.35 Volts, the charging electronics will switch from a constant current to a constant voltage

…

lithium ions are traveling from one electrode to the other and inserting themselves within the electrode. This is all happening within the battery and is transparent to you, the end user. Alongside this charging process, as you might imagine, there are other bad and undesirable things that are happening too. For example, it is easy to imagine that all the lithium ions will travel together and happily make the journey from one electrode to another. In reality, these lithium ions will “collide” and they will bond together to form dangerous deposits of lithium metal.

…

From their website there are links to a lot of review/discussion articles, e.g.
https://www.powerelectronicsnews.com/technology/pushing-to-the-very-edge-of-safe-li-ion-charging

[ggf31416]

I don’t understand the collision explanation. It doesn’t sound likely that lithium ions that should have the same (positive???) polarity and thus should repel each other would collide and somehow form a deposit of lithium metal, but it has been years since I touched a chemestry book.

[EasyB]

It sounds like the basis of their algorithm is that you can charge faster at low states of charge than at high states of charge. This is because at high states of charge Li ions are going into the carbon anode, but there are already lots of Li ions there, so Li can instead plate as a metal on the anode, which is bad.

There is nothing intrinsically harmful about CC/CV charging, but the process can be sped up by charging faster at the beginning then tapering off the charge current. New phones and electric cars already do this.