SunPower Cell & Module Technology overview

Stefano G. Alberici, PhD, Sr. Trainer EU,

SunPower Corporation

New Delhi, 17.10.2012, Rooftop Workshop India

2 PV classical stereotypes…:

“Come on: A module is a module: they are

all the same. The only thing that counts is

the price. Why should I bother with other

items?”

“Come on: A kWp is a kWp: they are all

the same. Their production (kWh/kWp/y)

does not change when changing the

module. The only thing that counts is the

price. Why should I bother with other

items?”2

Most powerful PV modules in the market

Why you should bother? Here is why:SunPower – a differentiated technology

Industry leading panel efficiency: 20%, leading cell efficiency: 22,5%

Produce up to 50% more than conventional panels and up to 4 times more

than thin film panels per unit area

Best energy performance (kWh/kWp), averaged +7 to +9 %/y more than the rest of PV

Solid reliability & quality

Industry’s first 25-year combined power and product warranty

3

Maxeon

Technology

SunPower technology is better

444

Mo

du

le E

ffic

ien

cy

Standard

Efficiency

(16% cell)

HiT

(20% cell)

Selective

Emitter

(19% cell)

SunPower

E-Series

(22.5% cell)

20%

18%

16%

14%

14%

44

16%

19%

20%

22%

12%

Thin Film

CdTe

(12.2% mod)

Maxeon

Technology

Conventional solar: warranty returns

Reliability of PV Systems. J Wohlgemuth. Proceedings of SPIE, presented 11-August-2008

86% of conventional solar panel warranty

returns:corrosion / cell /

interconnect breaks

Maxeon

Technology

5

Front contact cellsSunPower Cell

Back side copper plating provides significant degradation advantage

Plated interlaced copper conductors

Ductile metal provide much more strength to the Silicon

Even if the Silicon cracks, the copper fingers maintain full conductivity, so a cell crack causes no loss of cell area and no measureable power drop.

Copper/tin plating is very robust against corrosion, and very easy to solder

Screen-printed metal paste

The baked-on paste offers no structural strength… all the strength is from the brittle Silicon wafer itself.

Very thin silver front-side metal lines oxidize/corrode over time

Lines are

alternating

(+) and (-)

copper

conductors

Maxeon

Technology

6

SunPower returns rate from 2006 to 2012:

33 ppm (200 / 6 milions)

Most efficient cells in the industry

7

SunPower Cells

22.5% efficiency

Conventional cells

Monocrystalline 15-17% efficiency

Conventional cells

Polycristalline 14-16% efficiency

SunPower cells are up to 50% more efficient than conventional

solar cells due to unique all-back contact design

Maxeon

Technology

Conventional Design Breakthrough Design

Stronger Materials

Front

Contact

Cell

Compared to SunPower Maxeon cell technology

Back

Contact

Cell

Conventional Monocrystaline

Technology

SunPower Maxeon

Cell Technology

More metal on the back = Higher durability & toughnessBack contacts = robust cell to cell connection & long-term operating lifeNo shading losses

Maxeon

Technology

SunPower panels produce up to 50% more power per m2

13

20%

19%

18%

17%

16%

15%

14%

13%

12%

SunPower

Panasonic

Sanyo

SunTech

SolarWorld RECKyocera

Solar Sharp BP Solar

As published in Photon International, July 2011

Highest Panel Efficiency by Manufacturer

Maxeon

Technology

15

Voltage builds rapidly at low insolation levels

Better performance in overcast conditions

Inverter wakes up earlier and runs later

Better low-light performance

SunPower SPR-90

Mono Crystalline Silicon

Poly Crystalline Silicon

CuInSe2

Amorphous Silicon

SunPower solar cells

generate more power at

low light levels relative to

other technologies

Sharper knee of curve at low light

levels is indicative of better low

light performance

Maxeon

Technology

Comparison SunPower vs. non SunPower:the effect of the Anti-Reflecting Glass on panels

16

NON SPWR

NON SPWR SPWR

Maxeon

Technology

Higher performance at higher temperatures

17

Due to lower temperature

coefficients and lower normal cell

operating temperatures (NOCT),

SunPower panels generate more

energy at higher temperatures

compared to standard c-Si

modules

Temp Coefficient:

SunPower -0.38% / °C

Std c-Si -0.47% / °C

NOCT:

SunPower 45 °C +/-2

Std c-Si 47 °C +/-2

0 5 10 15 20 25 30 35 40

(C°)

Maxeon

Technology

Operating temperatures: SPRW vs. standard c-Si

18

Higher efficiency modules operate at lower temperatures because they convert more

of the sun’s energy to electricity – lower efficiency modules convert it to heat instead

Temperature

difference

Time (h)

Maxeon

Technology

19

Maxeon

Technology

Highly accelerated life test (HALT)

Solar Simulator Dynamic Load

Test

Damp Heat TestAutoclaveUV Tester

Maxeon

Technology

Dynamic Load Test Results

CompetitorPower Loss = 2.1%

SunPowerPower Loss = 0%

Electroluminescence images of a front-contact module and SunPower back contact module

after dynamic load HALT stress (1000 cycles of +/-2400 Pa, equivalent to maximum wind

load, of alternating pressure load on the glass)

Maxeon

Technology

Reliability testing data: damp heat

SunPower cells are highly resistant to corrosion

22

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

110%

0 1000 2000 3000 4000 5000 6000 7000 8000

Po

we

r D

egr

adat

ion

Number of Hours

Performance of SunPower and Traditional Front Contact Modules in Damp Heat (85°C, 85% RH)

SunPower

1

2

3

4

5

6

7

Maxeon

Technology

SunPower performs better in hot arid climates

University of Arizona / Tucson Electric Test Yard

SunPower panels generate 8% more energy than the average of the rest of the field

For current SunPower panels: add 1-3% for AR glass plus 1% for rooftop temps

8%

11% more energy output

Cronin, Alexander, et. al. “Performance Reviews from the Tucson Electric Power Solar Test Yard,” 2011 data update.

23

Maxeon

Technology

6.2%

Average 9% more energy outputin third-party Energy Yield Studies

3rd party study compilation

Compilation of 10 large studies shows SunPower yield is well above the average mono- and poly-crystalline silicon PV Panel yield.

For current SunPower panels: add 1-3% for AR glass plus 1% for rooftop temps

Rose, Doug, et. al. “High-Confidence Prediction of Energy Production fro High-Eff PV Systems,” 25th PVSEC Valencia, Sept. 2010.

24

Maxeon

Technology

Industry’s first 25-year combined power and product warranty

POWER GUARANTEE

– More Power: at least 95% of the Minimum Peak Power for the first five years

– Less than 0.4% annual degradation for the subsequent 20 years

More lifetime energy: 9.1% above the industry standard

PRODUCT WARRANTY

– The solar industry’s first 25 year product and power coverage

– Coverage of warranty replacement costs

– Financial stability and product reliability to back our commitment

26

Maxeon

Technology

27

70

75

80

85

90

95

100

0 5 10 15 20 25

Gu

ara

nte

ed

no

min

al

P (

%)

Years of performance

Industry Standard SunPower Previous Warranty

Power warranty: what’s new

Industry Standard Previous

SunPower Warranty

NEW

SunPower warranty (as from July 1st)

Step:

90%: 10 years

80%: 25 years

Step:

90%: 12 years

80%: 25 years

Linear:

95% for 5 years

Year 6 – 25: -0.4%/yr

Power

warrantyProduct

warranty

SunPower New Linear Warranty

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

Industry leading 25-year product warranty

28

SunPower

Industry Standard Previous

SunPower warranty

The NEW

SunPower warranty (as from July 1st)

5-10 years 10 years 25 years

Jinko Solar

Kyocera NA

Solarworld, Sharp, First Solar,

Suntech, Canadian, Trina, Yingli

Hanhwa

Power

warrantyProduct

warranty

Years of performance

*Source: Companies’ websites & datasheets. Data as of 15 September 2012

Thank You