LiFePO4 terminals and straps chemistry

How do you store and manage your electricity?
User avatar
acmotor
Senior Member
Posts: 3603
Joined: Thu, 26 Apr 2007, 03:30
Real Name: Tuarn
Location: Perth,Australia

LiFePO4 terminals and straps chemistry

Post by acmotor » Thu, 24 Sep 2009, 18:53

This topic came from here

LiFePO4 (aluminium ?) terminals do present some challenges.
I guess the terminal arrangement chemistry comes into play as we mix Ali, copper, tin, lead, zinc, stainless and mild steel with perhaps some others thrown in.
Any material chemists out there who can shed some light on does and don'ts ?

David, tinning of straps helps reduce oxidising of the copper and promotes good surface contact due to the softness, however the electrical conductivity of lead/tin is less than ali or copper from memory. Tinning wants to be as thin as possible maybe with high silver content solder or an actual tin electroplate ?

What is the coating used on crimp terminals ?

Do you use any terminal grease/oil/wax to reduce corrosion/oxidising.
Its not the same idea as PbA terminals where you are dealing with (potential) acid but these differeing materials and moisture still mean that excluding oxygen from the terminals may be worth doing.

I wonder if TS or others recommend anything ?

I know the UWA getz had problems with straps (3 layered copper) and replaced them with solid tinned copper. I did think that the straps (having layed around for 18months) had oxidised even before fitting so surface resistance was an issue.

iMiEV MY12     110,230km in pure Electric and loving it !

djsharpe
Groupie
Posts: 90
Joined: Thu, 21 Feb 2008, 23:43
Real Name: David Sharpe
Location: Melb

LiFePO4 terminals and straps chemistry

Post by djsharpe » Thu, 24 Sep 2009, 19:15

I have ordered a commercial paste from an electrical wholesaler. This has 30% zinc dust which I hope will act as current paths. Ill treat about 10% of my cells and report on findings for different applied torques.
D

User avatar
acmotor
Senior Member
Posts: 3603
Joined: Thu, 26 Apr 2007, 03:30
Real Name: Tuarn
Location: Perth,Australia

LiFePO4 terminals and straps chemistry

Post by acmotor » Thu, 24 Sep 2009, 19:29

Great.

What prep of the ali termianls do you do before fitting straps. i.e. a scrape/sand to get fresh ali ? (given that the terminals are plain ali, they will oxidise, or corrode electrolytically in contact with straps. Both these effects being insulators of course)

What are your bolts/washers made of ?
What torque do you use on your terminal bolts ?
Looking forward to your findings. Image
iMiEV MY12     110,230km in pure Electric and loving it !

djsharpe
Groupie
Posts: 90
Joined: Thu, 21 Feb 2008, 23:43
Real Name: David Sharpe
Location: Melb

LiFePO4 terminals and straps chemistry

Post by djsharpe » Thu, 24 Sep 2009, 19:47

The TS cells came with 0 instructions. I used SS bolts & var washers. Applied torque intuitively only. No prior prep. I had good contact until the run to B'rat where high currents may have caused problems. With two chargers running (33A charging current-I'd have had a 3rd charger but EV Power bought them all otherwise 48A) you can find hot spots easily enough.
D

User avatar
acmotor
Senior Member
Posts: 3603
Joined: Thu, 26 Apr 2007, 03:30
Real Name: Tuarn
Location: Perth,Australia

LiFePO4 terminals and straps chemistry

Post by acmotor » Thu, 24 Sep 2009, 19:56

OK, so part of the thinking is, were these resistances there all along from original assembly of terminals or is there a degradation of contact quality ?

Any details of the commercial zinc paste so I can google ?
iMiEV MY12     110,230km in pure Electric and loving it !

djsharpe
Groupie
Posts: 90
Joined: Thu, 21 Feb 2008, 23:43
Real Name: David Sharpe
Location: Melb

LiFePO4 terminals and straps chemistry

Post by djsharpe » Thu, 24 Sep 2009, 20:01

Youll have to contaim yourself until I get the goods. There is also silica in the compound. A company called Dulmison makes something too. They have a fluoride compound which is supposed to break down the films.
D

djsharpe
Groupie
Posts: 90
Joined: Thu, 21 Feb 2008, 23:43
Real Name: David Sharpe
Location: Melb

LiFePO4 terminals and straps chemistry

Post by djsharpe » Thu, 24 Sep 2009, 20:06

You could prob make your own using Zinc dust, ground up sand & Vaseline. Zn dust ex paint shops. To grind up the sand, lay a bead of sand on your nearest railway line & await the train. Sweep up with kitchen brush & tray. A little railway iron into the mix too I guess.D

User avatar
acmotor
Senior Member
Posts: 3603
Joined: Thu, 26 Apr 2007, 03:30
Real Name: Tuarn
Location: Perth,Australia

LiFePO4 terminals and straps chemistry

Post by acmotor » Thu, 24 Sep 2009, 20:22

Ah, noalox or penetrox pastes seem to come up on seaches.
Plenty of forum comments too. Reading time....
iMiEV MY12     110,230km in pure Electric and loving it !

User avatar
acmotor
Senior Member
Posts: 3603
Joined: Thu, 26 Apr 2007, 03:30
Real Name: Tuarn
Location: Perth,Australia

LiFePO4 terminals and straps chemistry

Post by acmotor » Fri, 25 Sep 2009, 02:34

http://www.idealindustries.com/prodDeta ... dId=30-026

Features
* Anti-oxidant and anti-seizing compound
* Reduces galling and seizing on aluminum conduit joints
* Suspended zinc particles penetrate and cut aluminum oxide
* Carrier material excludes air to prevent further oxidation
* Improves service life of aluminum electrical applications
* For use with all types of pressure-type wire connectors

Now where can I get it in Oz ?
iMiEV MY12     110,230km in pure Electric and loving it !

User avatar
acmotor
Senior Member
Posts: 3603
Joined: Thu, 26 Apr 2007, 03:30
Real Name: Tuarn
Location: Perth,Australia

LiFePO4 terminals and straps chemistry

Post by acmotor » Fri, 25 Sep 2009, 02:36


IDEAL INDUSTRIES AUSTRALIA
Level 6 / 75-85 Elizabeth St
Sydney, NSW 2000
Australia

GPO BOX 5124
Sydney, NSW 2001
Australia   

   
Telephone 1300 765 800
61300 765 800
Fax 1300 765 801
61300 765 801
Mobile: 0405 123 100
61405 123 100
E-Mail: Michael.Florence@idealindustries.com
iMiEV MY12     110,230km in pure Electric and loving it !

Squiggles
Senior Member
Posts: 742
Joined: Wed, 22 Apr 2009, 03:19
Real Name: Neil
Location: Newcastle NSW

LiFePO4 terminals and straps chemistry

Post by Squiggles » Fri, 25 Sep 2009, 03:16

There is a compound used in the electrical distribution industry when joining copper to aluminium. Can't remember it's name.

Somebody out there must know it though.

If you are looking for something to apply after the joint is tight try one of the lanolin based products. They are damn good.

User avatar
woody
Senior Member
Posts: 1715
Joined: Sat, 21 Jun 2008, 02:03
Real Name: Anthony Wood
Location: Mt Colah

LiFePO4 terminals and straps chemistry

Post by woody » Fri, 25 Sep 2009, 04:04

I've seen NOALOX mentioned on the Thundersky Yahoogroup:
Jan from Newport Rhode Island wrote: I don't know if all the terminals are made of the same metal but my
LFP40aha cells had Stainless bolts and washers and aluminum posts
that they screwed into. The aluminum posts carry almost all the
current so making sure the top surface of the post that mates with
the copper strap is clean and free of oxides. I sanded them with a
foam sanding block wetted with Noalox - an aluminum connection
compound made for electrical connections which prevents further
oxidation and reduces contact resistance. I also applied Noalox to
the bolt threads since it also acts as an antisieze compound. You
are correct about stainless for electrical connections . . . not
very conductive but it does not corrode easily.
Edit: wrong type of bracket/brace
Last edited by woody on Thu, 24 Sep 2009, 18:11, edited 1 time in total.
Planned EV: '63 Cortina using AC and LiFePO4 Battery Pack

User avatar
acmotor
Senior Member
Posts: 3603
Joined: Thu, 26 Apr 2007, 03:30
Real Name: Tuarn
Location: Perth,Australia

LiFePO4 terminals and straps chemistry

Post by acmotor » Fri, 25 Sep 2009, 19:13

I guess Jan means nuts and washers ?

So why isn't everyone using noalox or similar on their aluminium terminalled LiFePO4 ? Image

BTW, I'm using bright zinc plated bolts and washers rather than SS.
Looks like zinc is still second best though to ali bolts as supplied with SE cells. My thinking was that, as the zinc was sacrificial to the ali, the terminals would remain in good condition. I was going to smear with a silicon grease but the noalox product seems just the ticket.

FYI my online enquiry to Ideal...
________________________________________________________________________
Hi,

We do not have a distributor in Australia that specifically handles this
product but they can bring it in for you.

Here are the sizes & prices.


30-030            8 oz bottle - $21.50 ex tax
30-031            8 oz brush-cap - $24.87 ex tax
30-032            1 gal $154.50 ex tax

Price does not include freight to Perth.

Regards,

Michael Florence
Sales Manager - Australia & New Zealand

IDEAL INDUSTRIES
Level 6 / 75-85 Elizabeth St,
Sydney NSW 2000

Mobile:           0405 123 100
Skype:            michaelflorence
Email:            michael.florence@idealindustries.com

________________________________________________________________________
iMiEV MY12     110,230km in pure Electric and loving it !

Nevilleh
Senior Member
Posts: 773
Joined: Thu, 15 Jan 2009, 18:09
Real Name: Neville Harlick
Location: Tauranga NZ

LiFePO4 terminals and straps chemistry

Post by Nevilleh » Wed, 30 Sep 2009, 18:02

I would've thought that mixing Cu and Zn would be a bad thing! I seem to recall making a simple cell out of a piece of Cu and a piece of Zn and just adding water (dirty water, so's to be an electrolyte). One or the other of the metals disappeareded at an alarming rate, I can't recall which.
My SE cells have a Cu cathode with a big Al nut holding it in place, an Al anode with a similar nut and they supplied Cu connecting straps with SS bolts.
I had thought I would make sure everything is clean when I assemble it all and then just spray all of the connectors with clear lacquer to stop oxidation.

User avatar
acmotor
Senior Member
Posts: 3603
Joined: Thu, 26 Apr 2007, 03:30
Real Name: Tuarn
Location: Perth,Australia

LiFePO4 terminals and straps chemistry

Post by acmotor » Tue, 06 Oct 2009, 21:10

Well as I understand it (high school chemistry only), mixing copper and ali is bad news. Worse then copper and zinc on the old electrial valence tables ?

Spraying the outside of a dry assembled joint may be a good idea, however it appears the electrical industry already knows what to do.
(possibly a practice that has wained in this world of designed obselescence)

Neville, remember the electrolyte ? that is the key to making a battery (and the resulting terminal reactions).
The purpose of the 'terminal paste' is to exclude oxygen and provide in this case zinc, which is sacrificial to the other terminal metals and aids in conductivity rather than simply using an insulating grease. At the same time stopping the formation or ingress of any electroltye forming contaminents. Moisture and oxygen being the worst offenders as far as I can follow the process.

Anyway, I have found this UTILUX equiv. of the US Noalox product...

UTILUX H2397
ELECTRICAL JOINTING COMPOUND
Recommended whenever aluminium is part of a connection
• H2397 with zinc particles suspended in a no melt grease penetrates
the oxide film on aluminium surfaces and provides low initial contact resistance
• The compound in the joint seals out air and moisture
preventing oxidation or corrosion and ensures high conductivity
CAT NO. NO. APPLICATION PART COLOUR TUBE SIZE
H2397 4C Conductive compound with zinc particles Zn KD Grey 325g

It was $25 +GST a tube at Middy's data and electrical in Melbourne although made by Utilux in North Wyong NSW according to the tube.

Image
Last edited by acmotor on Tue, 06 Oct 2009, 10:22, edited 1 time in total.
iMiEV MY12     110,230km in pure Electric and loving it !

Nevilleh
Senior Member
Posts: 773
Joined: Thu, 15 Jan 2009, 18:09
Real Name: Neville Harlick
Location: Tauranga NZ

LiFePO4 terminals and straps chemistry

Post by Nevilleh » Tue, 06 Oct 2009, 22:56

Yes, that makes sense, keeping the electrolyte has to be the key.
I'll see if I can find some. I do have "sacrificial" zinc anodes on my boat for the very reasons you have described.
Working car is getting closer!
Last edited by Nevilleh on Tue, 06 Oct 2009, 11:57, edited 1 time in total.

HeadsUp
Groupie
Posts: 265
Joined: Sat, 28 Feb 2009, 09:13
Real Name: Mark W
Location: Sydney

LiFePO4 terminals and straps chemistry

Post by HeadsUp » Mon, 09 Nov 2009, 03:02

is noalox enough ?

i know boatbuilders will never use Aluminium and copper together coz the Ali starts resembling teenage acne

if you have to , i have been told to use a stainless steel fitting in between Ali and Brass or Ali and copper.... on boats

never heard of the creams though , TS dont mention it   Image

User avatar
acmotor
Senior Member
Posts: 3603
Joined: Thu, 26 Apr 2007, 03:30
Real Name: Tuarn
Location: Perth,Australia

LiFePO4 terminals and straps chemistry

Post by acmotor » Mon, 09 Nov 2009, 03:29

HeadsUp,
The key seems to be in the zinc being sacrificial and the grease base excluding air so no electrolytic corrosion. The electrical industry seems to be right into the terminal pastes.
There's a lot TS don't mention !
iMiEV MY12     110,230km in pure Electric and loving it !

User avatar
photomac
Groupie
Posts: 306
Joined: Tue, 17 Nov 2009, 21:56
Real Name: Matthew Clifton
Location: South Perth

LiFePO4 terminals and straps chemistry

Post by photomac » Mon, 30 Nov 2009, 21:17

This begs an ignoramous's question -
In reference to the fat, high DC carrying, orange cables(Conductors) seen in most EV conversions - are they copper (automatic assumption) or are they Aluminium (bonus of being lighter) akin to the High voltage power lines?
Yes,   we can.   Image
Hyundai Kona 64 v1 Sept 2019 onward. 00016 up to 3850+
Mitsubishi PHEV v1 Apr 2016 to Aug 2019 14500 to 72000km
Nissan LEAF v1.0 Nov 2013 to Apr 2016 00035 to 36000km

User avatar
evric
Site Admin
Posts: 500
Joined: Sun, 20 Jul 2008, 01:57
Real Name: Eric
Location: Adelaide SA
Contact:

LiFePO4 terminals and straps chemistry

Post by evric » Mon, 30 Nov 2009, 21:20

Copper
Prius Plug-in Conversion: http://www.evplus.com.au ...Holden Barina EV: http://www.evric.kestar.com.au

User avatar
photomac
Groupie
Posts: 306
Joined: Tue, 17 Nov 2009, 21:56
Real Name: Matthew Clifton
Location: South Perth

LiFePO4 terminals and straps chemistry

Post by photomac » Mon, 30 Nov 2009, 21:44

Thanks evric
Mmmmmmm?
Is an Aluminium cable a preferable/possible option.
They are lighter. But in the vain of this chemistry thread would Al be better than Cu?
Yes,   we can.   Image
Hyundai Kona 64 v1 Sept 2019 onward. 00016 up to 3850+
Mitsubishi PHEV v1 Apr 2016 to Aug 2019 14500 to 72000km
Nissan LEAF v1.0 Nov 2013 to Apr 2016 00035 to 36000km

User avatar
evric
Site Admin
Posts: 500
Joined: Sun, 20 Jul 2008, 01:57
Real Name: Eric
Location: Adelaide SA
Contact:

LiFePO4 terminals and straps chemistry

Post by evric » Mon, 30 Nov 2009, 21:53

I think the copper is more flexible, even though the al is lighter.
Prius Plug-in Conversion: http://www.evplus.com.au ...Holden Barina EV: http://www.evric.kestar.com.au

User avatar
lithbattboss
Groupie
Posts: 241
Joined: Thu, 03 Apr 2008, 21:50
Location: Sydney

LiFePO4 terminals and straps chemistry

Post by lithbattboss » Mon, 30 Nov 2009, 21:56

photomac wrote: Thanks evric
Mmmmmmm?
Is an Aluminium cable a preferable/possible option.
They are lighter. But in the vain of this chemistry thread would Al be better than Cu?

Copper is preferable to aluminium cables for several reasons. Copper is more flexible (easier to work) and is more resistant to fatigue failures.
Aluminium cables must be larger to carry the same current as copper cables.
Where power matters.
XPS Power cells 25C discharge for high performance applicatiopns.
www.lifetechlithium.com

User avatar
Johny
Senior Member
Posts: 3729
Joined: Mon, 23 Jun 2008, 16:26
Real Name: John Wright
Location: Melbourne
Contact:

LiFePO4 terminals and straps chemistry

Post by Johny » Mon, 30 Nov 2009, 21:57

I would think that it is difficult to make a multi-strand aluminium cable to improve it's flexibility.
With that in mind, aluminium would be mechanically unsuited to the shaky, shaky mobile environment (IMO).

bga
Senior Member
Posts: 492
Joined: Mon, 01 Sep 2008, 19:27
Real Name: Bruce Armstrong
Location: Perth WA

LiFePO4 terminals and straps chemistry

Post by bga » Wed, 02 Dec 2009, 01:43

I would have gone for 'impossible' on a multistrand aluminium cable.

The US housing industry started using aluminum [US] cable about 30 years ago, but had problems with fires. I believe the the problem was that of corrosion and thermal expansion. The coefficient of thermal expansion and creep properties of aluminium are sufficient that the joints work loose after a time and overheat. This was solved by the introduction of suitable fittings, see here .

Bellville (conical) spring washers may be good on aluminium battery / busbars etc.
Last edited by bga on Tue, 01 Dec 2009, 14:44, edited 1 time in total.

Post Reply