New High capacity Li-Ion high cycle count

[csm]

The problem has been that cylindrical cells are hard to electrically connect together. The traditional way to interconnect them is with welded nickel strips. The drawback to this is that the electrical resistance is high, the welds break easily and welding together thousands of cells is very cumbersome.

So, spot-welded connections have a higher electrical resistance than two pieces of metal simply pressed against one another?

I have read reports that the spot welding process can cause an internal damage to the cell which can result in more internal resistance. I am not sure how to prove this.
I too am puzzled why we haven't seen more pop in batteries, like nimh. I suppose it has to do with trying to limit potential liability issues of people sticking them into chargers that over charge? Or sticking cells together that would be imbalanced? Perhaps with the newer lithium chemistry and more advanced charger technology, this will no longer be an issue? Perhaps cells could be embedded with RFID that communicates with the charger to give the important info on charging(voltage, AH, C charge rate).. and if it does not have the RFID tag, it just will not charge?

[dogman]

Swimming with the sharks now eh? But the comments are correct. We've all been around the block a few times here, especially when the only source of good c rate cells was dismantled drill packs. A lot was learned about good and bad ways to make connections on little round cells. Mostly though, small round cells are a real pain. At least use 2 ah cells or larger.

When decent c rate RC lipo that didn't explode hit the market at good prices, we flocked to it like geese to a corn field.

Similaly, a lot of folks are now looking hard at 20 ah A123 pouch lifepo4 now that you can finally get your greedy hands on it.

What's hot here changes a couple times a year sometimes.

[Pablo_1985]

http://www.ntsworks.com/New_Battery.html

I get there from here:
http://green.autoblog.com/2012/05/18/ne ... #continued

It seems to be the same guy who developed Zero motorcycles.

Regards

[Lock]

http://www.ntsworks.com/New_Battery.html

Breakthrough Interconnection System
The problem has been that cylindrical cells are hard to electrically connect together. The traditional way to interconnect them is with welded nickel strips. The drawback to this is that the electrical resistance is high, the welds break easily and welding together thousands of cells is very cumbersome.

Our new patent pending interconnection system is entirely different. We mechanically connect the cells together with pressure. It is very difficult to make a reliable pressure contact that can carry up to 10 amps and do it for pennies of cost. This was an incredible challenge.

Hmmmm....

Upgradeable And Reusable
Having a standard sized cell that is easy to replace also means that when newer higher energy cells come out, it's easy to upgrade. There are already 4.1 ah versions of the 18650 cells due for production in 2013. This will be a 20-25% increase in energy density.

Hmmmm....

Neal T Saiki
Neal Saiki is a proven innovator of electric motorcycles, full suspension mountain bikes, rock climbing gear and numerous other products. HIs goal is always to always to refine technology until it is simplified elegance. In his spare time, his interests include martial arts, mountain biking, motorcycles, jewelry design, rock climbing and airplanes. Combining work and play has always been the common theme among Neal's endeavors.
SNIP
In 2005, Neal worked on electric motorcycles and founded Zero Motorcycles. Zero has become the leader in this fledgling industry. He retired from Zero in 2011 in order to resume working full time on the human powered helicopter.

[docnjoj]

hmmmmmmmm... is right L0ck! Seeing will be maybe believing. If accurate and true it could help thos folks who like soldering together hundreds of connections. Not me anymore.
otherDoc

[deVries]

Here's a thread where I try to follow any battery capacity breakthroughs... If you haven't seen it yet, then you can find more related info there:

Attn Experts: When Will Battery Capacity Double ?

This NTS breakthrough seems to be more related to battery design & getting more efficient cell connections! Huge improvement if 15kWh gets you 100 REAL miles.

[Lock]

From here:
http://www.ntsworks.com/Bicycles.html

World Class Bicycle Design
Although not widely publicized, Neal Saiki has been the designer behind dozens of world class bicycles for high end brands such as Haro, Santa Cruz and Mountain Cycles. Neal's product development business developed bicycle designs which would be sold or licensed to established brands.

Neal has been a long time motorcycle enthusiast and combining motorcycle suspension technology with bicycle design has revolutionized the mountain bike industry. In 1994 Neal designed one of the early full suspension mountain bikes and for the next fifteen years he has been at the leading edge of bicycle design.

...yet the emphasis at NTS seems more motorcycle-class... Perhaps the mechanical connection isn't rugged enough for bicycles, but do-able for larger road-going eMotorbikes

L

[Jeremy Harris]

We now seem to have three threads running on this topic, perhaps we could merge them?

(the other two threads are: search.php?&sr=topics&search_id=newposts&start=50 and viewtopic.php?f=14&t=39980 )

[neptronix]

please merge them

[Pablo_1985]

Merge them please, i did not see the other ones :S

[nealsaiki]

Good comments! I wanted to clarify a few things about my battery interconnect technology.

Yes, it is correct that when you use super high energy density cells (>200 wh/kg) they run hot over 1c discharge. Tesla can do it because they have active liquid cooling. I favor passive air cooling and staying under 1c discharge. Can't fight I^2R either.

I don't have plans to make packs for electric bicycles because there is plenty of good technology out there for connecting small packs together. When you make a huge pack, it's totally different. Just working with thousands of cells can be a nightmare.

The biggest problem is thermal heating of the pack. Welded nickel tabs are fine for small packs, but copper interconnects have 4 times less resistance and they don't easily get warm when you run current through them. My technology also covers much of the ends of the cells with a conformable layer of copper for both low resistance and good thermal transfer. Tiny spot welds are not good for either thermal transfer or resistance. 1 milliohm in resistance makes a difference when it comes to thermal transfer. Big high energy density packs run hot and it's a problem that most people don't appreciate.

The main problem with EVs is that they have too little range. It's a total buzz kill to have an EV and constantly have to worry about getting stranded. The packs I design use the lowest cost/wh of any lithium battery technology (when you buy millions of cells). I wouldn't call them "massively oversized", I'd call them barely acceptable!

Ebikes are totally different. You can always pedal home. EVs need to have extra range. You don't want to have to constantly charge during the day and getting stranded is not a real option.

Neal Saiki
CEO NTS Works Inc

[Lock]

Hello Neal

Welcome to the Sphere. Nice to see you here.

Apart from "ebikes", think one size up, as eScooters... eg the EVTs with a 2kWh pack... Any interest in packs approx this size? I believe there'll be a huge amount of growth in this segment over the next few years.

Lock

[redorblack]

The other major consideration that Tesla had to deal with was safety... they've got every single cell fused on both sides, got each sheet of cells fuses and the entire pack fused... all on top of the active water cooling system. I see no mention of the safety issues involved with a bad cell in a multi-cell pack. On CandlepowerForums you can find photos of the aftermath from flashlights that became pipebombs using 18650 cells in series. What will this connection method do to deal with that?

[nealsaiki]

Yes, I am working on 3+kwh modules for scooters. It is going to be a huge market in the next few years.

Safety is a great question. It's the reason I'm not inclined to sell to hobbists. There are so many ways to make a safe or unsafe system.

Cells have evolved a lot since Tesla first introduced their car and now many safety features can be built into the cells. 18650 cells are very safe due to their limited cobalt content and steel housing. PTC fuses and current interrupt devices are pretty much standard, although you can certainly order whatever you want when you order in quantity. The Tesla system is geared toward high performance and so it's safety system has to be very complex. At low C rates, PTC fuses in the header of the cell are fine. My system also facilitates external PTC fuses at every cell junction on top and bottom of each cell. I also have a built in thermal fuses at both ends. These are independent of current.

Many new 18650 cells will 100% pass a nail penetration test.

Another difference is that I favor thermal contour mapping of the cell array to identify cells getting hot way before a thermal runaway. My technology facilitates extensive thermal measurement of every cell and it's all built into the walls of the pack. This technology identifies problems much earliery than fuses and gives you the ability to replace the cell before failure.

I also have technology that isolates each cell to prevent cell to cell flame propagation with a 1100 degree fireproof barrier. One cell going up in smoke is bad and stinky, but not a dangerous event.

The tricky part was doing all this an to still keep it cost effective. I've spent a huge amount of time on this, but I think the battery is really the most under-developed part of an EV.

Good questions!

[csm]

http://www.ntsworks.com/New_Battery.html

Anyone found any pictures and/or video of this "Breakthrough Interconnection System"?

[nealsaiki]

I made a little video with a summary of the technology. It still doesn't show you how it's done, but rather it explains what it can do. I have a couple of OEM manufacturers that are licensing the technology. Their products should come out next year.



Neal Saiki
CEO NTS Works