Hai, Here battery fabrication cycle mainly projecting electrode fabrication,there different experiment occur on this field ,here one of the study on dry process electrode fabrication
Objectives of this study
• The Phase I objectives of this program are:
+ The binder presently is not electrochemically stable in a lithium battery anode. Therefore phase I will define a binder system for dry process anode fabrication that is stable over 500 cycles to full state of charge.
+ Identify the thickness limit for dry process cathodes that can meet EV rate and cycle life criteria
• The Phase II objectives of this program are:
+ Produce a dry-process anode material that capacity matches the Phase I cathode.
+ Produce at least 250m of free standing dry process cathode at thickness >200 µm thickness.
+ Validate cost model by running pilot coating line at >25 m/min.
+ Deliver 24 cells in A123 SOA EV cell format (>60Ah prismatic can)
Approach
• Establish baseline for oxide electrode materials.
• Modify PO4 electrode powder for compatibility with dry process.
• Increase PO4 cathode loading to 2X limit of baseline slurry casting process.
• Operate cathode process at pilot scale.
• Validate cathode manufacturing cost reduction.
• Identify dry-processible binder with electrochemical stability at anode potential.
• Meet anode mechanical and electrode interface requirements at lab scale.
• Demonstrate SOA PHEV/EV cell to validate materials utilization cost reduction. Progress Update - Cathode
• Prior trials conducted with LiFePO4
+ Design of experiments conducted to determine film making characteristics of nano-phosphate material
+ Initial nano-phosphate processing results
– Thick film formation was successful
– Single-sided free standing film down to 175 micron with reasonable flexibility achieved
– Challenge: Films thinner than 175 micron became very stiff
– Incapable of rolling without fragmentation/crumbling
– Films were very dense
+ Initial blends of nano-phosphate materials have shown a resistance to thin electrode film formation
– Further work will consider formulation, particle morphology and processing parameters to achieve good thin film properties Progress Update - Cathode
• Establish baseline with oxide electrode materials
+ Mixed metal oxides other than nano-phosphates show good initial results
– Films down to 85 microns were formed
– Density slightly higher than target
– Films demonstrate reasonable flexibility
– Films at 100 micron thickness show very good properties
– Flexible with good mechanical properties
– Loading approaching targets
– Process parameter optimization necessary to make thinner films with better density characteristics
Conclusion
The dry electrode process innovation in this proposal will provide the ability to coat thick and fast, while eliminating solvents and saving energy.
• The projected readiness level is TRL 7 for the cathodes upon completion of the program, with confidence that the development path will closely follow the previous scale up of the dry process for ultracapacitor electrodes.