On our RC Lipo's from a reasonably qualified authority.Β* (Don't Ask, Don't Tell)Β*
Max do not exceed voltage 4.23 Vdc per cell (New battery, ideal conditions)
A used cell may be slightly lower.
The currrent density issue may be that the current is not always evenly distributed, andΒ* a very small area may see a much higher than expected current density.Β*
Some years ago, I stopped at a library that had a good collection of recognized technical references, and due to what I was working on at the time, I ended up really looking into just about all practical batteries (Other than Li batteries) for use on military aircraft over extended temperature ranges.
About all I can say today is that each battery type has it's advantages and disadvantages. Obviously, Li rechargeable batteries are a bit more finicky than other choices.Β* The more energy you pack into a confined area, the higher the chances that something can go wrong.Β* The range of battery life spans goes from minutes to decades for more or less off the shelf batteries.Β* Railroads and phone companies used the really long lived Pb batteries and alternatives, with weapons of various types using the short lifetime batteries.