Nishi no-solder compression pack-building kit from India

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Dec 8, 2017
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There have been others before. Over time, they have all improved (thanks, competition!), and here is the most recent competitor. The solderless/no-spot-weld compression contacts system uses a separate spring element that does not act as part of the electrical conduction chain. It also includes a cap over each spring, which simplifies construction of the top and bottom panels.

If you are in a hurry, the money shot is at 14:00

 
That's an interesting design. I like the overall build of it. But, I think it won't take off very well. It takes so much time to build the pack and all of the parts are so separate. So many tiny pieces.
I wonder what the longevity of the pack is. The caps are press fit into place. How long will they hold before the spring pushes them off. If you put the pack in a tight spot it might not be an issue (well, until you actually need to pull it out and the caps are pressing against the case), but if the packs are hanging on the wall or on a shelf, will they push off after awhile or loose contact between the tabs and the cells.

It definitely needs some time to prove itself. Maybe they can figure out a way to make the packs a bit easier to build.
 
Very clever how you use the small buss bars on the negative side on the last row at one end of pack.

I was wondering how you would achieve good contact at this location with negative side of batteries where wrap stands proud of end of cell

How do you handle connections for the BMS for each row? Just extend the buss bar out over edge of pack

Any flexibility to incorporate fuse wire?
 
Very well thought out design , I particularly like the way you can easily add constructed packs together , which is not that easy with standard black connectors...

You correctly realised the spring should not be in the electrical circuit ... I calculated one spring as having a resistance of about 21 milliohms !! that's a lot ..... but are you sure pushing the spring on the strip gives a low resistance connection ...

Bottom line is the price ! ...what's the cost per cell ...where can we buy ??

Other similar systems are ridiculously expensive ... totally unsuitable for powerewalls where packs will be in service decades ...

But I'm sure there;s a market for things like electric bikes , where cells will not last long , and the pack can be dismantled and the connectors used again
 
It appears as though the bus strips are copper ribbon with a thin zinc plating, which would carry a decent amount of current. However, one of the things I like the most about this is that...with the springs being a separate element, and the "over cap" holding everything in alignment...I can easily swap-in my own bus-ribbons, of any type I like.

If this pack shown was set on edge (like on an ebike) the additional top-caps don't add much width, and it would be easy to add two side-panels to hold everything together in a more secure way...
 
The video description says silver coated copper, but that would be overkill compared to the normal zinc or tin. As for the springs pushing the cap off, I would definitely devise way to have outside plates screwed together to keep this in compression. Which just adds more parts and complexity to this option.
 
Korishan said:
That's an interesting design. I like the overall build of it. But, I think it won't take off very well. It takes so much time to build the pack and all of the parts are so separate. So many tiny pieces.
I wonder what the longevity of the pack is. The caps are press fit into place. How long will they hold before the spring pushes them off. If you put the pack in a tight spot it might not be an issue (well, until you actually need to pull it out and the caps are pressing against the case), but if the packs are hanging on the wall or on a shelf, will they push off after awhile or loose contact between the tabs and the cells.

It definitely needs some time to prove itself. Maybe they can figure out a way to make the packs a bit easier to build.

I posted the above on the video comments. This is their reply:

NISHI INDUSTRIES said:
Thank you for all your inputs; here we gonna say 1. the components of the pack are build with first quality of raw material, not the reprocessed one, so they will go well for years and years until it is dropped off or not used properly. 2. We had made sure the threshold of the sockets ( caps ) coming out is far more away as compared with the tension of springs. The spring tension is enough to a make sure of the contacts between the cells and tabs and not more than enough that it will push off the cap since we have tested these in real bad conditions. Else if you want you can laminate the pack which will increase your peace of mind. lastly the assembly of 1*4 and so on are into planning, which we come out later as the upgraded version of the same.
 
Ahhh I recognize these springs.

These are some thick phosphor bronze/beryllium copper springs, or whatever kind of copper alloy they are using.

Very nice :)
 
Nishi finally got back to me. They donot currently have a dealer in North America. However, I may be purchasing a handful (just so I can write about them). Is anyone else curious about these? I could send a sample to a few builders when I am done examining them and taking some pics.
 
When the hammer entered play I started to wonder if you got really frustrated with the build process what would happen :D
 
spinningmagnets said:
Nishi finally got back to me. They donot currently have a dealer in North America. However, I may be purchasing a handful (just so I can write about them). Is anyone else curious about these? I could send a sample to a few builders when I am done examining them and taking some pics.

Im very interested in seeing reviews from you and other common youtube uploaders in our community. Im not sure Im interested in a sample, but if someone were to set up a group buy then I would probably participate in it.
 
ShannonWilliams said:
Making a solderless contact isn't the hard part, its doing that with every cell fused.

Nishi seems very professional ... probably has qualifications in electrical engineering (as I do) , and realises fusing each cell is unnecessary and ridiculous.

A big error was made by early powerwall pioneers in fusing cells , because they clearly hadno depth knowledge of this subject.

I'm sorry if thatruffles some peoples feathers , but it's true IMHO.
 
And you are allowed to have opinions. I will not risk not fusing second hand cells. Personally I fuse every cell which also helps with human error as I have in the past tried to plug a pack in backwards and unfused I'm sure I would have had a massive issue but all the fuses popped on the pack i was inserting with zero issue from the rest of the powerwall. just resolder those fuses and poof back in service.
 
Current status is...trying to find the "swift code" so I can wire transfer money to Mahindra bank in Mumbai. I will encourage them to open an account in a US based bank to simplify wholesale business to dealers...

As to fusing. I realize this forum has evolved from "DIY powerwalls" into "Second life storage", which emphasizes its most often discussed subject of repurposing affordable used cells that still have quite a bit of life left in them. When it comes to used cells, I strongly agree that fuses are very important. I would like to repeat my research that indicates...soldering a thin wire from a fuse onto the positive end of an 18650 cell is the most appropriate style. between the two ends, the negative is clearly the most sensitive to heat-damage. In fact, soldering onto the negative end might be a contributing factor in cells going bad.

So...how to connect onto the negative end? Spot-welding clearly works, but it makes replacing a cell that has gone bad, into a somewhat annoying task. For a low-amp connection, I believe a pressure-contact is adequate and desirable. If one cell in a 20P group has "gone the way of the buffalo", then the remaining 19 cells will still do fine while providing 1/19th more amps each, compared to before. You notice the fuse is fried, and you replace the bad cell with a newer one. The negative is a pressure-contact, and the positive is a soldered fuse-wire.

I'm not saying that this is the best idea for me, or even a good idea for anyone. I'm just saying it might be worth experimenting with, yes? Plus...with all the smart builders here, why can't we design a pressure contact for the positive end that incorporates a replaceable fuse? How hard can that be?
 
spinningmagnets said:
Current status is...trying to find the "swift code" so I can wire transfer money to Mahindra bank in Mumbai. I will encourage them to open an account in a US based bank to simplify wholesale business to dealers...

I'm very keen to know the price per cell the end user will have to pay .... I have been using the standard black holders which work out at 9c/cell but this is unacceptably high ... some big powewallers have spent many hundred $ s on these ... there's no need for any of this !!

My aim is to develop the ultimate system , no holders , no busbar , spot welded , it's a work in progress , it will be quiet similar to the way some build their bike batteries ....

I suspect the price of nishi's system will be over a dollar per cell ... ridiculously expensive an inappropriate for powerwallers , even for bikers these holders make the battery bulky and heaviercompared to what is now standard , a big consideration.


spinningmagnets said:
Current status is...trying to find the "swift code" so I can wire transfer money to Mahindra bank in Mumbai. I will encourage them to open an account in a US based bank to simplify wholesale business to dealers...

As to fusing. I realize this forum has evolved from "DIY powerwalls" into "Second life storage", which emphasizes its most often discussed subject of repurposing affordable used cells that still have quite a bit of life left in them. When it comes to used cells, I strongly agree that fuses are very important. I would like to repeat my research that indicates...soldering a thin wire from a fuse onto the positive end of an 18650 cell is the most appropriate style. between the two ends, the negative is clearly the most sensitive to heat-damage. In fact, soldering onto the negative end might be a contributing factor in cells going bad.

So...how to connect onto the negative end? Spot-welding clearly works, but it makes replacing a cell that has gone bad, into a somewhat annoying task. For a low-amp connection, I believe a pressure-contact is adequate and desirable. If one cell in a 20P group has "gone the way of the buffalo", then the remaining 19 cells will still do fine while providing 1/19th more amps each, compared to before. You notice the fuse is fried, and you replace the bad cell with a newer one. The negative is a pressure-contact, and the positive is a soldered fuse-wire.

I'm not saying that this is the best idea for me, or even a good idea for anyone. I'm just saying it might be worth experimenting with, yes? Plus...with all the smart builders here, why can't we design a pressure contact for the positive end that incorporates a replaceable fuse? How hard can that be?

Many illogical statements in that post ... you have assumed used cells are more dangerous and so should be fused . but a pack build with new cells , after hundreds of cycles is composed of used cells , does this represent a danger ....
The danger with these cells is when they are punctured or crushed , a fuse will not help this ... I believe tesla started all this nonsense because of the pressure they were under from lawsuits , in bad accidents crushed cells caught fire ...what could they do .... NOTHING ... but they had to APPEAR to do something .. they know the public understands fuses keeps things safe , so they spent 1c per cell putting in fuses and told the public problem solved ... 2 years latter nothing is solved , the fires still continue , in very rare severe crashes ...
You also assumed if a cell goes bad it will blow the fuse , it won't , just slow discharge all cells in parallel the fuse stays intact ....

Millions of bike users and others have been using unfused cells at very high drain rates for many years with no trouble and these batteries all contain "old and used "cells after 300 cycles.
 
Tesla replaced the CID with the fuse since it was simpler and cheaper. They did not add the fuse wire as just extra fuse but replacing one system with another cheaper one. Atleast thats what I have been told but someone might be able to confirm that?

Also note that mixed 2nd hand cells are not the same as new cells aged together :) Those cells you know how they lived meanwhile 2nd hand laptop cells as example can be all from new to severely damaged due to bad use.
 
I am not against re-purposing used cells that have ~70%-80% of their useful life left, assembledinto a DIY powerwall. If the price is near free, and a builder has some time on their hands, then...why not?

As to using new cells in a stationary assembly. When purchased in bulk from a respected supplier, they all have the same capacity, and the same level of design and build quality, and the same age. I'm not saying that fuses are un-necessary, but...if I was giving advice to a friends, I would strongly recommend using fuses on every cell if re-purposing used mystery cells.

For a stationary power wall, the Nishi system is un-necessary, and there are cheaper options that are readily available andcommonly used. I'm just saying that the Nishi system exists, and if a new reader has questions, then..."Second Life Storage" should be their first stop for accurate information.
 
I just received a shipment of the Nishi kit. The standard kit is a box with enough parts to inter-connect 54 cells of the 18650 format. (108 cellend-caps, plus bus strips). According to their website, the price is $25 USD for the kit, and $25 USD to ship to Kansas. So it is roughly $1 per cell.

I am certain that if someone made a very large purchase, there might be a price-break, and the shipping could be much cheaper. I am currently looking for someone that can test a sample. Something along the lines of four cells set up to measure the 12V amps, raise the amp-draw an amp at a time, record the temperature of the buses.

The cell-to-cell interconnects are copper strips that have been plated for anti-corrosion. The plating is dull and silvery, perhaps Zinc, tin, or nickel. The dimensons are 0.4mm thick, and 7.6mm wide, so the copper cross-section is roughly (7.6 X 0.4=) 3.04mmsq, so...bigger than 13ga round wire, and smaller than 12ga.

For our purposes, lets call them 13ga

https://www.engineeringtoolbox.com/awg-wire-gauge-d_731.html
 
Hi spinningmagnets!

Thanks for telling us about another solderless system in such a detailed way! Have you tested the Vruz?nd system? If yes, could you make a comparison chart between them, including the price-per-cell, weight-per-cell and added_volume-per-cell data?

P.S. I think both Vruz?nd and Nishi are way behind the NESE system from Agnius, which seems to me much less complicated and more reliable if made of hard-to-melt plastic.

image_eowuyc.jpg
 
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