Elect. Guru help

[jruiz]

Originally Posted by GregAndrew

Yeah, that is not where I was going with my question. Seems to me that any batteries that are charged or discharged too quickly beyond their ratings will have a tendency to generate heat. Although that is a risk that everyone should be aware of when making their wiring connections to avoid shorts.My concern was that some of the cells seem designed for rapid discharge and some for slower discharge. And I was wondering if that was going to effect performance (battery life or run time). Also, I am not looking at LION batteries, but Lithium Iron Phosphate batteries (LifePo).

Short answer to your question, no. Long answer is that cell designers adjust the rate capability of a component cell by varying the thickness of the electrodes which directly affect your effective current density. Thicker electrode cells have lower current capability but higher energy density and thinner electrode cells the opposite.

Pack designers on the other hand adjust the current capability by adjusting the number of cells in parallel. Energy density in this instance stays constant and capacity increases.

Heat, fast charge/discharge, and the state you leave your battery at have the most impact on cycle life and irreversible capacity loss. Most battery manufactures ship batteries between 25-50 percent state of charge to maximize battery life and safety.