PROCESS INNOVATIONS
NorSun has a
roadmap
for
cost
reductions
through
process
innovation
in
the
crystal
pulling,
ingot
shaping
and
wafer
slicing
portion
of
the
monocrystalline
high
efficiency
solar
energy
segment.
ROADMAP
A set of well-defined initiatives aimed at reducing cost per wafer by 40 - 50 % by 2012:
EXAMPLE OF PROJECTS
An example from crystal pulling:
Replenishing crucible to increase batch size:
- Increase batch size to make longer crystals
- Replenish melt to produce multiple crystals from each cycle
- Reduce cycle time in batch process
- Reduce cost through lower consumption of consumables per kg ingot
- Increase yield through reduced waste
Status:
- Additional charging tool developed internally
- Good test results
- Currently being implemented in regular production
An example from wafer
slicing:
Wafer slicing with diamond coated steel wires:
- Capex reduction due to more efficient slicing (fewer saws)
- Avoidance of costly silicon carbide grits and polyethylene glycol
- Improved wafer quality due to more consistent thickness and lower metal content on wafer surface
- Reuse of wire (normal steel wire is only used once)
- Recycling of polysilicon kerf for PV application expected
- Reduced electricity consumption
Status:
- Joint development project with a cell manufacturer (Qcells), a saw manufacturer (MeyerBurger), a diamond wire producer (Diamond Wire Technologies), and a recycling company (Garbo)
- Two wire saws using diamond in Årdal
- 100 % productivity increase per saw demonstrated with stable cutting process
- Solar cells made by customer without efficiency loss compared to conventional wafers