This document discusses the development of IEC 62804, which provides test methods for detecting potential-induced degradation of photovoltaic modules. It describes discussions that were held with experts to update the document. Key discussions included changing the damp heat test startup from non-equilibrium to equilibrium, reducing the humidity tolerance, and whether to increase the stress levels of the tests. While some argued for more stringent conditions, others felt the existing 60°C/85% RH test was sufficient as a basic qualification test. The document also reviews decisions made around including both foil and damp heat tests and changing the document type from standard to technical specification.

1. IEC
62804
Status
Update
NREL
is
a
na3onal
laboratory
of
the
U.S.
Department
of
Energy,
Office
of
Energy
Efficiency
and
Renewable
Energy,
operated
by
the
Alliance
for
Sustainable
Energy,
LLC.

2. 2
2
Phone
Discussions
with
NC-­‐nominated
Experts:
Document
82/685/NP
Focused
discussion
during
Fall-­‐Winter
2013/2014
Francois
Rummens
Claudio
Licio1
Karl
Berger
Michael
Koehl
Yoshihito
Deguchi

3. 3
3
October
2014
(Kyoto)
– CD
comments
received
and
discussed,
major
items
include:
2nd
test
type
described:
Al
foil
test
providing
full
surface
ground
electrode
applied
to
glass,
proposed
by
DKE,
included
per
decision
at
WG2(non-­‐voted)
Moving
test
from
pass/fail
“qualifica3on
test”
to
descrip3on
of
how
to
do
the
test,
without
pass/fail
criteria
(voted)
– Title:
Test
Method
for
Detec3on
of
Poten3al
Induced
Degrada3on
of
Photovoltaic
(PV)
Modules
(non-­‐voted)

4. 4
4
CD
comment
period:
some
key
results
– 60°C/85%
RH
test
moved
from
non
equilibrium
startup
to
equilibrium
startup
Non-­‐equilibrium
startup
placed
excess
humidity
on
sample
surface,
applying
significant
stress.
– G.
Mathiak
(TUV
Rheinland)
confirmed
by
others.
Requested
by
DKE
to
move
to
an
equilibrium
start-­‐up,
significant
12-­‐24
h
wait
at
T/RH
stress
condi3ons.
RH
tolerance
moved
from
±
5%
to
±
3%,
a
five-­‐lab
round
robin
shows
this
was
readily
feasible.
Temperature
tolerance
remains
at
±
2°
C,
with
a
sec3on
from
references
IEC
60068-­‐2-­‐78,
Environmental
tes3ng
-­‐
Part
2-­‐78,
included,
discussing
the
precedence
of
cri3cality
of
maintaining
3ghter
temperature
tolerance.
In
view
that
“test
method”
values
reproducibility
over
the
specific
magnitude
of
the
stress
level,
the
change
to
equilibrium
start-­‐up
was
made.

5. 5
5
Damp
heat
–
V
profile
Thanks
to
Bengt
Jaeckel,
Karl
Berger,
for
the
ini3a3ve
to
make
the
first
and
second
itera3ons
of
this
example
profile

6. 6
6
Recent
revision
history
Dec
24,
2013
–
Dra
sent
by
email
to
WG2
– Concern
about
Al
foil
test
being
Not
severe
enough
Not
represen3ng
frameless/rear
rail
modules
– Wish
for
85°C/85%
RH
condi3on
(reality
in
China)
Increased
clarity
that
equilibrium
start-­‐up
of
damp
heat
test
was
less
sever
than
turning
on
voltage
at
the
beginning
of
the
damp
heat
cycle.
Some
more
severe

7. About
the
origin
of
the
60°C/85%
RH
condi/on
7
7
In
Florida,
USA
–600
V
Horizontal,
near
ocean
Normalized Power
1.0
0.8
0.6
0.4
0.2
0.0
Type
1,
60°
Type
2,
60°
0 50 100 150 200 0
Test Hours
1.000
Normalized Power
0.975
0.950
0.925
0.900
0 2000 4000 6000 8000
t (h)
In
chamber
85%
RH
–600
V
Type
2,
85°
Type
2,
50°
Type
1
Type
2
Module
Type
1:
Acceptable
performance
in
the
field
survives
with
less
than
5%
power
drop
in
chamber
with
85%
RH,
60°C,
rated
system
voltage,
for
96
h
Type
1,
con3nued,
with
control
32
months
In
Florida,
USA
–600
V
Horizontal,
near
ocean

8. 8
8
Stress
levels
60°C/85%
RH
DH
–Vsys
condi/on
now
rendered
less
stressful
because
of
the
startup
change.

9. 9
9
Voltage
applied
on
start,
then
combined
T,
RH
Ramps
(early
dra
sequence)
Leakage current
spike, if different
from chamber to
chamber could
conceivably
contribute to
poorer
reproducibility
excess stress
Spike
in
leakage
current
from
excess
humidity
on
module
Simultaneous
ramp
of
T,
RH,
and
voltage
bias
Simultaneous
ramp
down
OK
60°C/85%RH/8
h
dwell
Also
see:
G.
Mathiak,
et.al.
TÜV-­‐R
27th
EU-­‐PVSEC

10. 10
10
T
ramp/dwell
èRH
ramp
èV
ramp
(later
dra
sequence)
Short
spike
of
leakage
current,
otherwise
very
stable
Sequen3al
ramp
of
T,
RH,
and
voltage
bias
Na3onal
Renewable
Energy
Laboratory
Simultaneous
ramp
down
OK
60°C/85%RH/8
h
dwell

11. Ini/al/final
Pmax
with
direct
glass
grounding
11
11
M1 8
M 19
M 2 0
M 2 1
M 22
250
200
150
100
50
0
/
W
PM PP
before
test
after
test
Test
condi/ons:
25°C,
-­‐1000
V
DC,
120
h
M18
–
perforated
foil
M19
–
water/foil
M20
–
mat/foil
M21
–
foil
with
gaps
for
some
cells
M22
–
Al
plate

12. 12
12
Stress
levels
60°C/85%
RH
DH
–Vsys
condi/on
now
rendered
less
stressful
because
of
the
startup
change.
I
suggested
35%
increase
in
stress,
based
on
leakage
current
analysis
and
work
of
J.
Berghold.,
60°Cà65°C.
– Idea
not
favored
based
on
62804
experts
feedback
60°C/85%
RH
already
adopted
in
na3onal
documents
“Just
a
minimum
basic
test,
no
need
to
change”

13. 13
13
Stress
levels
60°C/85%
RH
DH
–Vsys
condi/on
now
rendered
less
stressful
because
of
the
startup
change.
I
suggested
35%
increase
in
stress
based
on
work
of
J.
Berghold
and
leakage
current
examina/on,
60°Cà65°C.
– Idea
not
favored
based
on
62804
experts
feedback
60°C/85%
RH
already
adopted
in
na3onal
documents
“Just
a
minimum
basic
test,
no
need
to
change”
Why
not
just
make
it
85°C/85%
RH
China
frequently
tes3ng
to
85°C/85%
RH/96h
PI
Berlin
championed
85°C/85%
RH/48
h
condi3on
Concerns
about
SiN
cell
AR
coa3ng
degrada3on
some3mes
seen
at
85°C/85%
RH
thought
not
representa3ve
of
field
failure
also
happens
in
the
field

14. 14
14
Silicon nitride degradation (DH +V bias)
TTF:
85°C
85%
RH
+600V
2000
h
ΔP=
-­‐29%
rela3ve
Outdoors,
same
type
of
module
+1500
V
bias
~4
y
ΔP
=
-­‐6.8%
rela3ve

15. Why
not
just
make
it
85°C/85%
RH
96
h
or
so?
Type
1,
con3nued,
with
control
15
15
In
Florida,
USA
–600
V
Horizontal,
near
ocean
Normalized Power
1.0
0.8
0.6
0.4
0.2
0.0
1.000
0.900
0.800
0.700
0.600
Type
In
Florida,
USA
–600
V
Horizontal,
near
ocean
1,
60°
Type
2
Type
2,
60°
0 50 100 150 200 0
Test Hours
1.000
Normalized Power
0.975
0.950
0.925
0.900
0 2000 4000 6000 8000
t (h)
3
Y,
now
In
chamber
85%
RH
–600
V
Type
2,
85°
Type
2,
50°
Type
1
Type
2
Module
Type
1:
Acceptable
performance
in
the
field
degrades
to
5%,
In
just
8
h
(non
equilibrium
start-­‐up)
Normalized Power
0.500
Generic Make
Type 1
04/2011
07/2011
10/2011
01/2012
04/2012
07/2012
10/2012
01/2013
04/2013
07/2013
10/2013
Date
32
months
Module
Type
1:
conven3onal,
PV
module
made
before
PID
even
hit
the
radar.
It
does
OK
in
the
field
Concern:
pu6ng
85/85
as
the
only
reference
condi3on
may
needlessly
raise
cost.

16. 16
16
Recent
revision
history
Dec
24,
2013
–
Dra
sent
by
email
to
WG2
– Concern
about
Al
foil
test
being
Not
severe
enough
Not
represen3ng
frameless/rear
rail
modules
– Wish
for
85°C/85%
RH
condi3on
(reality
in
China)
Also,
increased
clarity
that
equilibrium
start-­‐up
of
damp
heat
test
was
less
severe
than
turning
on
voltage
at
the
beginning
of
the
damp
heat
cycle.
April
8,
2014,
Dra
sent
by
email
to
WG2
– 85°C/60%
RH,
and
25°C
Foil
test
given
as
minimum
stress
levels,
alterna3ve
higher
test
temperatures
also
given
per
the
feedback
to
the
dra$s.
– Mr.
Deguchi
(Japan
expert)
requested
alterna3ve
higher
test
levels
be
changed
to
notes.
Done.
– Discussions
and
sugges3ons
in
expert
commi5ee
about
just
choosing
1
condi3on
each
for
the
test
types
(Foil,
DH),
but
no
jus3fying
data
provided.

17. 17
17

18. 18
18
Busan
WG2
decisions
Foil
and
Damp
heat
tests
both
included
– Language
around
the
foil
test
sta3ng
it
does
not
account
for
module-­‐level
designs
intended
to
mi3gate
degrada3on
by
reducing
leakage
current
pathways
to
ground.
For
example,
it
defeats
protec3ons
that
may
be
placed
in
the
PV
module
construc3on
to
minimize
metal
contact
to
the
module.
– Changed
from
standard
to
technical
specifica3on.
– TITLE
:
TEST
METHODS
FOR
DETECTION
OF
POTENTIAL-­‐INDUCED
DEGRADATION
OF
CRYSTALLINE
SILICON
PHOTOVOLTAIC
(PV)
MODULES

19. 19
19
Hereout-­‐
IEC
62804
distributed
as
TDS
(82/885/DTS),
comments
close
2014-­‐12-­‐05
– Editorial
changes
Reference
IEC
61215
Ed.
2
or
Ed.
3?
What
does
the
future
look
like?
Needs
– Qualifica3on
test
Need
to
boil
down
to
one
stress
level
for
qualifica3on
test
Environment
–dependence
is
of
interest
– Inclusion
of
thin
film
in
another
rev
of
62804
First
Solar
says
they
are
essen3ally
in
favor
of
the
62804
document:
They
are
good
with
it
applied
to
their
modules
More
data
is
needed
to
say
the
stress
levels
are
meaningful
with
respect
to
the
various
technologies
and
mechanisms

20. Peter
Lechner,
ZSW
20
20
Some
thin
film
technologies
show
coulomb-­‐specific
accelera3on