I've never got a good answer. "Safer" is too ambiguous to me
Hello again Jake. We've been over this before in another thread. Let me try an analogy that might help explain the differences between safety levels of LiCo, LiMn, and LiFe Li-Ion cells.
Let's say we want to drive a car for one mile down a road at high speed without having a tire blowout. This stretch of road is littered with broken glass bottles, boards with nails in them, scraps of sharp metal, as well as other road hazards, that cannot be avoided no matter how you steer the car down the road.
Now lets say we have a choice as to what tires we can fit our car with. First we have the choice of racing tires intended for track use. These tires are specially formulated with soft rubber compounds which aid in making the tire more "sticky" so as to hold the road better. Additionally, these type tires have a fairly thin tread design, so as to save weight, and add to the cooling efficiency. For this analogy these tires compare to LiCo/ICR Li-Ion cells.
Our second available choice of tires we can use to run this course are intended for normal use, such as may be found on the typical "family car". These tires have a compromise in tread formula which is a bit harder, allowing for better tread wear, but still retain a reasonable amount of traction. Additionally these tires have a thicker tread design, as weight is not as much of a concern for normal driving and performance. These tires we will parallel to the LiMn/IMR Li-Ion chemistry.
Our last available choice of tire type for this treacherous one mile run down the road is a tire designed for off road use, typically installed on vehicles with 4WD. The rubber formulation used in these tires is harder, and tougher so as to withstand typical off road conditions, such as gravel roads, rock climbing, driving over small tree limbs etc. Tires in this category usually have a much thicker tread, often with a tread depth alone, of as much as one inch, or more. Also, weight is not a consideration with these type tires, as the benefit of adding strength to the design is much more important than saving weight with these type tires. We will equate these tires to LiFe/IFR Li-Ion cells.
OK, we now have three choices as to which tire we can fit to our car to attempt the one mile run down this hazardous course. Considering the obstacles to be encountered, we know there is a reasonable chance that we will have a blowout, regardless of which tire we choose. That leaves us with trying to decide which tire type would be the "safer" bet to complete the one mile run without having a blowout.
Perhaps this wasn't all that good an analogy. I mean Li-Ion cells and tires?
Still, there are some parallels, but also some areas where no direct link can be made. As far as safety though, I think the analogy is adequate. LiCo cells cannot take as much abuse as the other two chemistries. LiMn are somewhere in the middle, and LiFe cells are the most resistant to abuse. They can all "blowout" though.
As I said in the other thread, there really is no "safe" Li-Ion cell chemistry. Some are just "safer" than others.
Dave