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Solar Cell ( Photovoltaic Cell)

12/24/2011 2:18 AM

What is the life capacity and cost of the Single Solar Cell?

What are the elements present in Solar cell?

How to manufacture the solar cell?

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#1

Re: Solar cell ( Photovoltaic cell)

12/24/2011 2:40 AM
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Guru
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#2

Re: Solar Cell ( Photovoltaic Cell)

12/25/2011 12:49 AM

Is it a student home work question?

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#3
In reply to #2

Re: Solar Cell ( Photovoltaic Cell)

12/27/2011 8:37 AM

It has to be homework....for someone that doesn't want to take time away from their video games to read theri textbook.

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#4

Re: Solar Cell ( Photovoltaic Cell)

12/27/2011 9:05 AM

This is a historical question and we did asked every year at the beginning of solar cell development work.

Solar cell started on wrong footing with good reason. All the power is produced at p/n junction and p/n junction is less than a micron depth ( range from 0.4 to 0.8 micron) depth from the surface of silicon.

Total silicon thickness we needed to produce is max 2 micron and for all purpose abut 1 to 1.5 micron. This can be achieved by sputerring 1.5 micron silicon on stainless steel, kovar, aluminum, window glass and then create p/n junction by dopiing boron and phosphor. Generally one can do co-deposition of Boron and phosphor 20:80 and then coat and inplant phosphor and you have solar cell.

Typical solar cell in market is less than US$1.0. If done cheap one can have this in less than Indian rupees 10.00 to 20.00 per cell.

Materials which goes on cell are

On silicon we put below materials

1. ITO (Indium -titanium oxide) coating

2. Silver linning ( also called front silver)

3. Boron coating in back ( back reflector) to minimize photon loss)

4. Current collector ( this is ribbon of lead or silver lining in days of lead free)

We put all these in cover with window glass and light condenser to increase photon density on silicon cell to maximize power generation.

Single solar cell will generate less than 0.5 watt power and life is depended and is from one month to 5 years based on manufacturer

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#5
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Re: Solar Cell ( Photovoltaic Cell)

12/27/2011 3:32 PM

With a max life of five years, it seems going solar wouldn't be worth the expense.

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#6
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Re: Solar Cell ( Photovoltaic Cell)

12/27/2011 9:33 PM

What I mean is for 5 years it will have respectable efficiency and fill factor. After five years one will see slow degradation of solar cell and that has to do with non hermetic nature of solar cell.

If it is hermatic or in the space with no humididty then it last more than 20 years. I will not give more than 5 years of usable life on earth

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#7
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Re: Solar Cell ( Photovoltaic Cell)

12/28/2011 7:58 AM

Holly crap!

There are many different cell types. Their material and manufacturing is very different. Above there is an awful mix of thin film silicon and cristaline silicon solar cell. There are some process details for thin film cells, and materials for cristaline silicon cells. The same mix goes on for characteristics...

Silicon Cells exist in different sizes. A standard today is the 6x6inch cell. At efficiency in the range of 20% this means about 4.5Wp per cell, not 0.5Wp

I know an installation that has 30 plus years on earth and still works fine!

Also you might have noted that in general you get a 25 year performance warranty from just about any module manufacturer these days.

And finally, there it was the magic word "module". Who would care about the lifetime of a single cell without specifying an environment? The cells are always protected in a module.

even prices are wrong! A complete solar module costs you about $1/Wp, not the cell. (Wp=Watt peak, meaning a cell with X watt peak will produce X Watt at standard test conditions of 1000W/m2 illumination at a solar spectrum AM1.5)

@masyood, you are clearly not a novice to the subject. This makes it even sader when reading such c...

@PM there is a simple engineering law of nature: crap in => crap out. If you want a good answer make sure you ask the right question. Be specific about what you want and follow up on the process to make sure it stays on track!

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#8
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Re: Solar Cell ( Photovoltaic Cell)

12/28/2011 8:29 AM

I have not seen yet one 20% efficiency yet in commercial market. In defence we have done up to 34% efficiency. If we want to talk we can do on term of fill factor which is more logical to quality of solar cell.

When I was saying cell cost of $0.5 what I was saying is an average cost of cell which includes front ITO, silver and ribbon with back side material which is aluminum, boron and silicon doped aluminum and thermal expense with average business profit which is 15%

If you need break up how I did I will be more than happy to show you my work out sheet.

There is nothing right and wrong of solar industries. The very base when we started this development work we started at wrong footing we do not need silicon to make a solar cell but at the initial stage we used carrier wafer from silicon industries and end up as the material of choice in short summery.

This industry as far as I see if does not correct its material needs and cost is another burst waiting to happen.

Total silicon need is not more than 2 micron and there are good number of semiconductor tools and technology which can deliver this thickness on any material and the cell will have better efficiency than this but some how business grues are still basing this industry on silicon and that is wrong base. by proper selection of base you can remove back paste for photon reflection and so on to make it profitable business and bring closer to thermal power plant cost

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#9
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Re: Solar Cell ( Photovoltaic Cell)

12/28/2011 11:23 AM

See, I told you you were not a novice!

However, you have just changed cost down a factor two from your first post to this one. Even for solar that is a fast learning curve :-). Jokes apart, half a dollar per Wp for a cell ready to be stringed is certainly more reasonable than one dollar.

I am definitely looking forward to your cost breakdown!

as for the efficiency I reckon you are familiar with HIT. Here is justs the basic data sheet from Sanyo. It's a commercial product all right and close enough to 20%: http://us.sanyo.com/dynamic/product/Downloads/HIT%20Power%20215N%20(NKHA6)-8526400.pdf

I am familiar with the history of the PV industry and the chip industry influence in how mainstream PV is done today. However, from there to call silicon the wrong material is a far shot: Okay, cristalline silicon doesn't have the ideal bandgap and alignment. However, apart from this solid state physics point, it has quite a things or two going for it:

-the efficiency is actually rather good.

-the assemble cells to module approach makes it possible to sort out defective cells. Something that most thin film processes envy.

-It isn't nearly as expensive as people think

-Capex is a lot lower than for vacuum process based thin films and thus the investors risk is a lot lower because his write off is done in a much more predictable future than for thin film.

-and last but not least, there is no availability issue with Silicon!

Well, name the perfect material if you can!

all competing technologies currently in the market have their own issues:

-CIGS: probably the TF technilogy of the next years but what about indium availability for a TW market?

-CdTe: Cadmium toxicity and Tellurium availability for TW market? Efficiency seems to level off.

-thin film Silicon: currently too low efficiency and too high Capex

-DSSC: still nothing commercial? Efficient remains low and stability remains in doubt I presume?

-Gallium arsenide: We were talking cheap cells, right?

-organic: Still big stability issues and low efficiency.

- quantum dot cells: Looking forward to hearing good news but I have not geared anything that would make me believe they are close to market launch.

so whoever has a better material than cristalline silicon, I am really looking forward to learning more. I am especially interested to hear how they address not only technical feasibility but also material availability and capital needed. Someday it will happen and surely there are docens of labs working in it. Until it happens, silicon will be difficult to supplant.

I hope you don't misunderstand me, I have been working in TF solar for years and I would be delighted to see it break through. But with what is currently in the market cristalline silicon is still a step ahead. just look at thin film silicon. Efficiencies for multijunction devices are little above 10%. And look at the market picture: the manufactures are struggling to stay out of bancrupcy.

I dare you to make a list of all thin film solar companies existing in 2010-2011 and check again how many will be around in 2013.

as for cost: what is currently marketed as grid parity is not really the real deal, I think we both agree. However, if you go to the sunny places of this world, you would be surprised to find out the cost of fossil electricity compared to PV. PV is bound to take off big very very soon. I see no market bust for PV as a such induced by the state of the technology. If it will bust I reckon it will more likely be due to being sucked down in the abysse of the general global market crisis.

also have a look at the historic learning curve in solar. If you smooth out the boom-bust scenarios created by states like Japan in the early days and Spain more recently, you will find a very good correlation with quite a small variance. Suppose that due to the southern markets the PV market continues to grow and then extrapolate the cost from the learning curve.

PV is going through a rough time but there is a sunny future!

PS: fill factor is a scientists view of the quality of a cell. From a market perspective I tell you however, I don't care, just make it cheap!

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#10
In reply to #9

Re: Solar Cell ( Photovoltaic Cell)

12/28/2011 1:29 PM

For me a product is one which works all the time and not only when sun is up will work and when sun is down it will not produce power but will work from stored power in battery. I never like this approached when I was growing up and I do not like now. I was involved at very beginning of solar development from used wafer giving free and then charging for it to scrap dealer.

Then I understood they sale this to DOE and BP solar and they use them for solar cell development and then I got excited and made front silver, ITO printable ink and back aluminum.

Then realize this is not industry for us and this industry does not have furture and is unreliable on ground but is good for space use and then realize is not good even for space use.

For a true product

1. Needs to convert IR photon to electron. IR is coming to earth 24/7 and one can have reliable supply of power.

2. For short one need to develop method to deposit 80:20 silicon boron using sputtering

3. Develop p/n junction by phosphor doping

4. Coat with separation layer

5. Repeat 2, 3 and 4 steps multiple time ( minimum of three)

6. This will allow to convert all light photon to electron without help of back aluminum and heat generation

NASA use this to get 34%+ efficiency

This is like 486 of intel between 386 and pentium actual if this industry has to servive then needs to produce power in day as well as night or doom to failure.

I do not have liberty to tell you the name of material/materials which will do that

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#11
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Re: Solar Cell ( Photovoltaic Cell)

12/28/2011 3:04 PM

I understand that you are only disclosing the nature of such a material to Larra Croft on your dead bed... Because that's where things that do not have thermodynamic base belong.

IR radiation during night? Man, that's black body radiation. It is extremely low energy per photon radiation from the ambient temperture of the earth. At 300K it is around 450W/m2 emission from earth but by the simple laws of thermodynamics you can not get an efficiency larger than (T_high-T_low)/T_high. Where T_low would have to be your receiver temperature and T_high is likely not going to be far from 300K.

then consider that whatever you have in mind will not work perfectly, so you will only get a part of your theoretical efficiency.

so considering that you will not find an energy free cooling you receiver temperature will tend to the same temperature as your source of energy and your efficiency is zero...

whatever you have in mind, I hope for you that you have found the a revolutionary new thing and that you have verified that it isn't a new perpetuum mobile you want to waste your family home on...

why so negative about storage? Nature does it all the time and traditional energy does it all the time. All fossil fuels are a long term storage, barrages are storage, biomass is storage....

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#12
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Re: Solar Cell ( Photovoltaic Cell)

12/28/2011 3:56 PM

You got me wrong. I dropped my interest on this. This was early in my life ( in mid 1985/ 1991). Then I migrated to semi conductor and develop fascination with LED and SOFC and now interest is high temperature glass to make solid oxide fuel cell (SOFC) based green stationery and portable power as sole life goal and not only sun based solar.

Deep down I like system which work 24/7. You are correct IR is poor but it is better than nothing. That why if you read email carefully you will see a composite material and not silicon but material from the family germanium selenide and doped gallium selenide which will be converting both IR and visible light photon to electron with efficiency higher than what current is.

This comes with its own issue that is disposal and how much we can move to public

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#13
In reply to #12

Re: Solar Cell ( Photovoltaic Cell)

12/29/2011 11:40 PM

GA's to all the comments from Masyood and Tompa for an interesting discussion on the topic.

My single line comment at#2 was rated as GA by some members, thanks to them.

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