1. Lambda’s Battery History
Initial interest from A123 and DOE
Battery electrode drying too long and costly
Reduce high energy costs and large dryer footprint
Residual moisture and slurry drying targeted processes
Initial work was joint development with A123
DOE funded project enabled rental of VFM lab oven
Data on residual moisture removal very encouraging
Potential of slurry drying evaluated
Next project was joint development with Navitas
Initial results on drying of slurry quantified potential
Lambda proposed DOE funding with Navitas as subawardee
DOE contract awarded in late 2014

2. DOE Funded Project Standard VFM Power & Control Module
Custom process chamber developed for wider format roll-to-roll processing
Dries aqueous slurries at least 5X faster than conventional dryer
Battery partner confirmed equivalent battery performance

3. Status of DOE Project
Battery electrodes were dried in a roll-to-roll VFM system
Half and Single Layer Pouch cells confirm equivalence to POR
VFM system delivered to battery manufacturer
Currently being used in their pilot production line
Complete batteries have been produced from VFM dried electrodes
Results will be reported to DOE in late 2016
Lambda is working toward commercial implementation of VFM for battery electrode manufacturing
Lambda is actively discussing partnerships with end users and integrators

4. Why VFM for Batteries Faster drying time VFM is Complimentary
Smaller footprint (less WIP, JIT manufacturing enabler…)
Less energy required
Enables converting batch to inline
VFM is Complimentary
VFM heats volumetrically throughout, conventional heats outside - in
Complete oven replacement not necessary
Can be retrofitted into existing lines to improve throughput
VFM heating enables unique material microstructure
Faster drying without binder migration
Control pore formation
Allows uniform drying of thicker films

5. Conventional Heating or VFM
IR or convection heat surface of the electrode slurry
Internal heating depends on thermal conductivity
Thick slurries cannot be dried adequately
Electrodes are 30% - 40% porous
Pores do not conduct heat well with IR or Convection
VFM penetrates deep into electrode slurry
Heating is by rotational movement of polar (solvent) molecules
Pores enhance VFM interaction with polar molecules
Thicker slurries
VFM penetrates deep into slurry and simultaneously rotates all dipoles
Unlike IR or convection VFM does not dry surface first that results in surface defects

6. Drying Rate Comparison
Advanced Drying Process (ADP) employs both the higher microwave drying rate earlier in the process followed by the higher convection drying rate as illustrated in following slide.

7. Navitas Continuous coating/drying : Cathode Binder (PVDF) Distribution
Al foil
Surface
10 mm
Al foil
Surface
Standard drying
Advanced drying process
Binder is located at the dark blue spots in the EDX spectra
Binder distribution ratio (electrode surface to near foil substrate) observed values were <1.3 target

8. Advanced drying process
Navitas Continuous coating/drying : Anode Binder (CMC/SBR) Distribution
Standard drying
Advanced drying process
Cu foil
Binder is located at the white spots in the backscatter SEM micrographs
Binder distribution ratio (electrode surface to near foil substrate) observed values were <1.3 target

9. First formation cycle for Single Layer Pouch (SLP) cells

10. Capacity retention at discharge rates

11. Cycle life testing for HEC prismatic cells

12. Residual Moisture Removal
When complete cells are received into dry room the residual moisture must be removed before battery packaging
VFM reported to be substantially faster than vacuum batch
Faster VFM drying enables roll-to-roll processing
Potential to integrate more process steps with faster dryer

13. Impact on Existing Production Line
How to Increase Throughput?
Add a Vari-Dry VFM module onto existing ovens!
- Comparative module is to scale
- Increases line speed by 3-4 times

14. VariDry NMP Cathode Drying
Results obtained under DOE contract
VariDry proved to be 3X faster than hot air dryer
Hot Air Dryer
VariDry
VariDry as a Booster
Hot Air Dryer
VariDry
The effect for production:
A 30 meter long hot air dryer throughput is matched by 10 meter long VariDry system or increase throughput 4X with only 33% additional dryer footprint.
Reduced space, energy and improved morphology.

15. VariDry Aqueous Anode Drying
Results obtained under DOE contract
VariDry proved to be 5X faster than hot air dryer
Hot Air Dryer
VariDry
VariDry projected as a Booster
Hot Air Dryer
VariDry
The effect for production:
A 30 meter long hot air dryer throughput is matched by 6 meter long VariDry system or increase throughput a minimum of 4X with only 20% additional dryer footprint.
Potential for thicker films / higher loadings electrodes.

16. VariDry Power Savings Latest results obtained under DOE contract:
Objective: Confirm a target power savings of % by a direct comparison between VFM & Convection POR processes
Process: Independent runs for both POR and VFM for anode drying (graphite/H2O chemistry)
Results: Confirmed VFM reduces energy output per meter of material produced by nominally 70%
The result for production:
Only one third (33%) of the conventional power needed is required for electrode drying process via VFM

17. Additional Power Savings
POR oven does not turn off except for very long breaks
VFM oven can reduce to idle for breaks longer than 30 mins
VFM power consumption at idle = 3 kVA
VFM warm up time is less than POR
POR warm up time = 60 minutes
VFM warm up time = 15 minutes
VFM adds less heat to the manufacturing space
Good in winter but bad in summer!

18. VFM is also a more Green process
Time reduction
Cycle time reduced from >4 hrs to <20 minutes
Major benefit for process development or mixed lot production
Energy reduction
Energy transferred efficiently to the polymer – no energy wasted heating the oven
No energy required to cool the oven after cure
Example of energy savings in a non-IC application