SolaroSsaurius
New Member
- Joined
- Aug 27, 2022
- Messages
- 171
Thanks for your lengthy response!The 304 AH cells have some doping to the electrodes. There are a couple of possible candidates for doping.
One is lithium added to graphite negative electrode. This is to provide self charge forming of the Solid Electrolyte Interface (SEI) layer around graphite. Its primary benefit is to reduce manufacturing time and resource cost of the time-consuming charge forming process. It also reduces the amount of positive LFP cathode electrode lithium used up during normal 280 AH cell charge forming process. This yields about 5% more cell capacity. Downside is there may be a small amount of cell bloating as the cell is sealed during the self-charge forming process and the ohmic resistance will be slightly greater. The small amount of bloating gas will eventually diffuse out through the plastic grommet cell terminal seals.
Other candidate is small amount of graphene added to LFP cathode. Graphene additive adds cost but significantly improves the access yield to lithium from the positive cathode by improving electrical conductivity of LFP cathode. A 280 AH cell relies solely on fine carbon black powder to improve LFP cathode electrical conductivity to a useable level.
My guess is the 304 AH cells have cathode electrode graphene doping. Negative electrode lithium addition alone will not yield enough capacity increase. Curious thing is the 304 AH cells have slightly greater ohmic resistance compared to 280 AH cells, usually over 0.20 milliohms. Graphene alone should reduce ohmic resistance. Maybe both electrodes are doped.
Whenever additives are introduced to electrodes or electrolyte there is always the possibility of unforeseen long term detrimental side effects. Graphene doping has low risk of any detrimental side effects since it is very similar to existing carbon powder which has been used for years.
Only time will tell.
If you were buying cells right now, which cells (vendor?) would you bet?
(in my case, it's for a mobile application - campervan)