EE 237: Solar Energy Conversion Week 3: Crystalline ... AWS
EE 237: Solar Energy Conversion Week 3:
Crystalline Si based solar cells 1. Key Developments 2. Manufacturing April 17 2013 tanford University
1
Basics: PN junction as solar cell Quiz: Which is a better design ?
hv
hv p+
tanford University
n
p+
EE 237 : Aneesh Nainani
n
2
Relative Quantum Efficiency of the Bell Labs Cell
tanford University
EE 237 : Aneesh Nainani
3
Switching to p-type wafers and phosphorous diffusion
tanford University
EE 237 : Aneesh Nainani
4
Basics: PN junction as solar cell Quiz: Which is a better cell ?
hv
hv n+
p
p+
n
Silicon µe ~ 1300cm2/Vs µh ~ 400cm2/Vs tanford University
EE 237 : Aneesh Nainani
5
Radiation Hardness in p and n-type
tanford University
EE 237 : Aneesh Nainani
6
70’s: Back Surface Field
tanford University
EE 237 : Aneesh Nainani
7
Back Surface Field
tanford University
8
p-n vs. p-i-n ? hv
hv p+
n
p+
i
n+
Quiz:
Which is better p+/n+ or p+/i/n+
tanford University
9
Photogeneration and Photocurrent in pn and p-i-n Diodes
E
x
Electrons and holes outside the depletion region can diffuse the “wrong” direction, decreasing quantum efficiency. It is thus desirable to generate all photo carriers within the depletion region tanford University
10
Photogeneration and Photocurrent in p-i-n Diodes Structure and energy band diagram
Electric field and carrier generation distributions
Key feature of the p-i-n structure is that most carrier generation occurs in the high electric field region and current is entirely drift current. Results in both higher quantum efficiency and higher speed GOOD tanford University
11
Evolution of PV Cell Design
tanford University
12
80’s: Emitter Passivation
tanford University
EE 237 : Aneesh Nainani
13
PESC
tanford University
14
Evolution of PV Cell Design
tanford University
15
90’s: Rear Side Passivation
tanford University
EE 237 : Aneesh Nainani
16
tanford University
17
Evolution of PV Cell Design
tanford University
18
Finger Optimization
tanford University
19
Finger Optimization
tanford University
20
Schockley equation with Rs and Rsh
tanford University
EE 237 : Aneesh Nainani
21
Influence of Rs on the I-V curve
tanford University
22
Resistive losses and efficiency
tanford University
23
Sun Power Cell
tanford University
24
Generic Solar Cell: Loss Mechanisms Source: R. Swanson, SunPower
tanford University
25
An Advanced Solar Cell
Efficiency is increased substantially Best laboratory cell~25%(MartinGreen,UNSW) Source: R. Swanson, SunPower tanford University
26
tanford University
EE 237 : Aneesh Nainani
27
Manufacturing crystalline silicon solar cell
tanford University
28
mc-Si vs. c-Si
Quiz: Which cell is mc-Si and which is single crystal ?
tanford University
29
mc-Si vs. c-Si
tanford University
30
Czochralski Towers
tanford University
31
tanford University
32
Grains
tanford University
33
Saw damage removal & texturing
tanford University
34
Phosphorous emitter diffusion
tanford University
35
Anti Reflection Coating
tanford University
36
Screen Printing
tanford University
37
Screen Printing of Al at rear
tanford University
38
Screen Printing of Ag at front
tanford University
39
Firing
tanford University
40
Binning
tanford University
41
Module assembly
tanford University
42
Series connection (string)
tanford University
43
Parallel connection: I-V curve
tanford University
44
Series connection: I-V curve
tanford University
45
Complete module in series
tanford University
46
Lamination
tanford University
47
Crystalline silicon module components
tanford University
48
Upcoming changes in cell design
tanford University
49
tanford University
50
tanford University
51
tanford University
52
tanford University
53
Suggested Reading • Cell and Module • Applied Photovoltaics, Chapter 4 & 5 • http://bit.ly/115DsyO • Handbook of Photovoltaics, Chapter 7 & 6, http://bit.ly/XPtTQg • Evolution of cell design • HO4#: PV coming of Age, Martin Green
tanford University
EE 237 : Aneesh Nainani
54
Crystalline Si based solar cells 1. Key Developments 2. Manufacturing April 17 2013 tanford University
1
Basics: PN junction as solar cell Quiz: Which is a better design ?
hv
hv p+
tanford University
n
p+
EE 237 : Aneesh Nainani
n
2
Relative Quantum Efficiency of the Bell Labs Cell
tanford University
EE 237 : Aneesh Nainani
3
Switching to p-type wafers and phosphorous diffusion
tanford University
EE 237 : Aneesh Nainani
4
Basics: PN junction as solar cell Quiz: Which is a better cell ?
hv
hv n+
p
p+
n
Silicon µe ~ 1300cm2/Vs µh ~ 400cm2/Vs tanford University
EE 237 : Aneesh Nainani
5
Radiation Hardness in p and n-type
tanford University
EE 237 : Aneesh Nainani
6
70’s: Back Surface Field
tanford University
EE 237 : Aneesh Nainani
7
Back Surface Field
tanford University
8
p-n vs. p-i-n ? hv
hv p+
n
p+
i
n+
Quiz:
Which is better p+/n+ or p+/i/n+
tanford University
9
Photogeneration and Photocurrent in pn and p-i-n Diodes
E
x
Electrons and holes outside the depletion region can diffuse the “wrong” direction, decreasing quantum efficiency. It is thus desirable to generate all photo carriers within the depletion region tanford University
10
Photogeneration and Photocurrent in p-i-n Diodes Structure and energy band diagram
Electric field and carrier generation distributions
Key feature of the p-i-n structure is that most carrier generation occurs in the high electric field region and current is entirely drift current. Results in both higher quantum efficiency and higher speed GOOD tanford University
11
Evolution of PV Cell Design
tanford University
12
80’s: Emitter Passivation
tanford University
EE 237 : Aneesh Nainani
13
PESC
tanford University
14
Evolution of PV Cell Design
tanford University
15
90’s: Rear Side Passivation
tanford University
EE 237 : Aneesh Nainani
16
tanford University
17
Evolution of PV Cell Design
tanford University
18
Finger Optimization
tanford University
19
Finger Optimization
tanford University
20
Schockley equation with Rs and Rsh
tanford University
EE 237 : Aneesh Nainani
21
Influence of Rs on the I-V curve
tanford University
22
Resistive losses and efficiency
tanford University
23
Sun Power Cell
tanford University
24
Generic Solar Cell: Loss Mechanisms Source: R. Swanson, SunPower
tanford University
25
An Advanced Solar Cell
Efficiency is increased substantially Best laboratory cell~25%(MartinGreen,UNSW) Source: R. Swanson, SunPower tanford University
26
tanford University
EE 237 : Aneesh Nainani
27
Manufacturing crystalline silicon solar cell
tanford University
28
mc-Si vs. c-Si
Quiz: Which cell is mc-Si and which is single crystal ?
tanford University
29
mc-Si vs. c-Si
tanford University
30
Czochralski Towers
tanford University
31
tanford University
32
Grains
tanford University
33
Saw damage removal & texturing
tanford University
34
Phosphorous emitter diffusion
tanford University
35
Anti Reflection Coating
tanford University
36
Screen Printing
tanford University
37
Screen Printing of Al at rear
tanford University
38
Screen Printing of Ag at front
tanford University
39
Firing
tanford University
40
Binning
tanford University
41
Module assembly
tanford University
42
Series connection (string)
tanford University
43
Parallel connection: I-V curve
tanford University
44
Series connection: I-V curve
tanford University
45
Complete module in series
tanford University
46
Lamination
tanford University
47
Crystalline silicon module components
tanford University
48
Upcoming changes in cell design
tanford University
49
tanford University
50
tanford University
51
tanford University
52
tanford University
53
Suggested Reading • Cell and Module • Applied Photovoltaics, Chapter 4 & 5 • http://bit.ly/115DsyO • Handbook of Photovoltaics, Chapter 7 & 6, http://bit.ly/XPtTQg • Evolution of cell design • HO4#: PV coming of Age, Martin Green
tanford University
EE 237 : Aneesh Nainani
54
