Batteries and New Battery Technologies

Have been on a trip across Europe with the camper van, hence the delay.

I do believe the hi-tec material has been developed, but the tedious process of making two mirror imaged plates seems unfit for storage capacitors in the Kw range.
The dielectric is a thin oxide layer like in an electrolytic cap, so the working voltage is low, probably around 25 VDC and even lower for the prototypes. You might argue that there are also 450 V electrolytic caps, but they have such a thick dielectric skin the nano-scale indents in this technique would be filled up completely and the plates won't fit together anymore.

Let us assume 25 V is feasible and a 10 000 F capacitor can be constructed (present day technology doesn't reach that far). Fully charged it could hold 25 000 Coulomb: when discharged over 1 hour the average current would be 6.94 Amp, the power 0.0875 KW/h. For an electric vehicle with an acceptable range, you'd need an array of 1000 cells, that is a 10 million Farad capacitor. Because the infrastructure (terminals, wiring, safety devices) are the same as for a large lithium pack, is will be just as bulky and heavy, but at least 10 times more expensive.

That's why I do not believe it is the power storage technology we have been waiting for.

 

You must have had a ball.

I hope not that you are right. I count on those high KW power ones in 5 - 6 years time. I believe that EESTOR has working models, but have great manufacturing difficulties. If they make it the same way as Siemens make the polycab ones, by offsetting the two plates with the dialectric in the middle, 1000 plates each containing electrons the size of a soccer field, could easy do 1 million Farad. Yes, the voltage would be low, 2 volt probably but 60 "plates" would do a decent job for 12 Volt motors.

If EEStor could wound 3 very large reels (2 offset) and thereafter spray them under vacuum with the conductive material, they would have a winner.

I will be very disappointed, as lithium is not the solution, with only 2 countries having that stuff in the ground, China and a South American one I believe. They would hold us against the wall, like now with absurd high prices. We have some Lithium in the ground but it is not economical to process it.

I hope you are wrong, otherwise Lead and Lithium are not the ideal solutions for my boat.
Bert
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Yes Bert, it was fun. If you tell the navigation box to avoid highways, Germany suddenly becomes an enormous country. Even crossing Austria that way took us almost a day.

I fully agree that the future is not in lithium or lead technology. But it also isn't in elaborate processes with the same magnitude of complexity as making semiconductors because even mass produced it will never be cheap enough to compete with chemical storage.
Unless someone comes up with a simple solution the scientists have overlooked for the last 3 decades, I put my money on hydrogen, either in combustion engines or fuel cells.

How is your LiFe project doing?

 

Good to hear. Yes, Germany, special Starnberg and surroundings are a good place to be.

That may make sense, as the infrastructure for distribution is already in place. All what one has to do is to kick the oilcompanies out of the Mexican Golf sea.

Not very well. I finished what I wanted to know, but because China had delivered the wrong casings. Without lumps, I had to use 10 cents coins between the batteries and like Vic has said, the interconnections are sometimes of a conductivity problem. I have discovered a shop in Johannesburg who sells magnets and I will try Vic's solution to it.

I received an order from Wezep and that will keep me busy together with the electric propulsion system in a keel. I spoke to an Msc youngster, who designs brushless motor control, maybe I give him the order to make a spider web for me, maybe I should not do everything myself, although all the 80/110 Ampere 55 Volt Mosfets are in house. 20 of them. 2 parallel with two 50 Ohm resistors in the gates will give me enough for 120 Ampere and this times 3 for the 3 motor coils. The 55Volt is somehow worrying me. but for 12 Volt, it may just be good enough. I have had some bad luck with changing over to Windows 7 since 10/12/2009 and I just read yesterday an e-mail placed by Will that they have a solution for me at the Software thread here on the boat.net.

Also my motors are sitting already for over a month in the EXPRESS mail from HongKong. They forgot to put an invoice in the parcle and that was the end of my 3 days Express mail delivery. But don't worry, I am planning to get 100 years old, I have still all the time.
Bert

 

CDK,

I forgot, I saw an article from Frost and Sullivan in www.dataweek.co.za , that prototypes have been made up to 40% efficiency solarcells. It certainly does not tie up with my 26% maximum knowledge. What do you know about it.

Because that will be a tremendious boost for my project.
Bert

 

Looked at Dataweek, but couldn't find the article!

 

I know I had read it somewhere and made a mental note to ask you about it > You know how it goes. I could not find that article anymore in the hard copies I have. Thus I did a search. You think it is again "bla bla bla" to get funds? Or did I misread the 40%.

Go to www.dataweek.co.za and do a search on "all" and type in "40%" , this is what you get.

NREL scientist Angelo Mascarenhas, who holds patents in solar cell technology, realised that an LED is just the reverse of a solar cell: one takes electricity and turns it into light; the other takes sunlight and turns it into electricity. “We had been working with solar cells for 30 years," Mascarenhas said. “Could we find some device where we could just reverse the process of making solar cells?"

Indeed, they found it. NREL had won major scientific awards with its inverted metamorphic solar cells, in which the cells are built by combining layers of different lattice sizes to optimally capture solar energy. In fact, an NREL-produced IMM cell set a world record by converting 40% of absorbed sunlight into electricity. Along the way, “We had already developed some of the know-how to capture sunlight in this green spectral region," Mascarenhas said. They had not reached there, because solar cells do not need a green, but they had begun to understand the challenges of getting to a green.

Bert

 

Hi CDK, now we are back on track again, have you given it a thought what they really meant with 40%.
40% of what? Sunlight per 1 m2 at 12 o'clock at the correct angle? Or is it again blown out of proportion to get funds? What is your opinion.
Bert

 

It is a bit of both Bert.

Scientists set a standard for us: at the equator, clear sky, 12 o'clock, the sun bombards us with 1 Kw /m2 of total radiation, from infrared to Ultraviolet, the whole bunch.
Silicon junctions can only convert visible light and a bit of near infrared, they peak at 930 nM. Altogether they convert approx 15% into electrons ready and willing to move. Subtract the glass absorption and the frames, which leaves you with a little over 120 W/ m2.

Now someone claims he can convert 40% of radiation into electrical energy with a tiny laboratory cell. That means he has made a complex and compound semiconductor structure, sensitive far beyond the visible spectrum (380-720 nM).

Do I believe that?
Yes, there is a lot of ultraviolet (below 380 nanoMeter) that could be converted with gallium-arsenide and -fosfide, but the implications are horrendous because each layer has to convert what it can, yet be transparent for other frequencies to reach the deeper layers.

They may even succeed in building a real panel, which of course doesn't reach 40% efficiency because there need to be conductors to transport the electrons covering part of the surface. If the efficiency is doubled, satellite constructors will use that technology even if the price is 10-fold, but for you and me, the invention is meaningless because we find even a normal solar panel quite expensive.

So we patiently wait for the next revelation. This is the right part of the year while we are waiting for new pictures of the Loch Ness monster.

 

Thank you CDK, we can always count on you, for clear detailed information. I must check on the Australian site, were they do tests with 18% panels. You know CDK, 120 watt per m2 is just too little for me. 180 watt/m2 is what would be acceptable and I will be searching for the manufacturer of this kind of panel. Because in real life, 120Watt/m2 often will only give 80 -90 watts out, due to some cloud or angle or whatever.
Bert

 

Well, we are getting there. According to this report we can now have 1 kw of power from 6 m2. That is very promising

SCHOTT Solar has developed a technique allowing for multicrystalline solar cells with 17.6% efficiency to be manufactured on a large-scale industrial basis.
The 17.6% efficiency was achieved on the surface of the aperture and confirmed independently by ESTI (European Solar Test Installation).

Another solar cells produced in an industrial environment achieve peak efficiency of above 18%, SCHOTT Solar says.

The backside of the solar cell has been passivated by using a combination of different dielectric layers that feature local contacts – known as the PERC structure.

Technical data on the record module made of multicrystalline silicon solar cells:
Efficiency: 17.6% (pertains to the aperture area)
Open circuit voltage: 38.3 V
Density of short circuit current: 8.94 A
Module output: 258.0 W
Module surface: 1.4701 m2 (Aperture area)

 

Not so fast Bert!

Schott bought AEG solar when the shares were cheapest.
The 17.6% is for monocrystalline wafers, without glass and frame.
Their panels a sorted out in several quality classes, The best you can get is 14.5%, the lowest class does only 13.7%.
The polycristalline ones start at 12.6%, the amorphous ones at 6.6%.

I took these figures from the Schott datasheets.

In earlier discussions I used 100 watts / sq.m. as a rule of thumb. With their commercial product Schott offers a bit more than that, mainly because they have very large panels so the frame losses are lower than with the old Siemens SM50 and SM55.

An improvement yes, but only marginally.

 

Yes, correct, but everything helps. It is time, that solarpanels are made without frame, or with a very minute strong frame.

I was just yesterday quoted for 4 x 160Ah - 36Volt LiFePO4 (23Kwh) Rand 56.000,- (6000 Euro) not too bad, but charging is a problem. The charger has to be developed in house. Charging at 0.1C, i.e. 16 Ampere is probably the best overnight. I still think a pipe system is not a bad idee. This in view that one can easy remove some batteries and balance them.
Bert

 

Hey Bert,
i'd be happy to buy 23kWh LiFePO4 for 6000 Euro!! Is it possible to ask how old are they / where do they come from?
Best,
Arn0

 

ok so whats the verdict

could the tesla system of a zillion little high end batteries be favorably applied to a day tripper boat