Correct mounting of LiFePO4 batteries

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PeterR
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Correct mounting of LiFePO4 batteries

Post by PeterR »

I'm about to mount my 45 LFP200AHA batteries and would like to do it properly.

I was intending to fit 3mm corrugated plastic spacers between each of them, as I remember that being recommended some time ago. That may have only been necessary for the earlier Lithium Ion batteries. Do I need to secure them all together with external straps?

I am struggling to find a clear set of rules that apply to current LFP batteries.

I would appreciate learning of the correct mounting requirements.

Thanks,
Peter

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evric
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Correct mounting of LiFePO4 batteries

Post by evric »

The Thundersky Instruction Manual shows cells strapped together with no spacers between.
Download from their website on the Tech Support page.
Here's the direct link to the PDF:-
http://www.thunder-sky.com/pdf/2007030222.pdf
Page 25 and 26 shows special metal straps and end plates!

Ric.
Last edited by evric on Tue, 06 Jan 2009, 19:23, edited 1 time in total.
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antiscab
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Correct mounting of LiFePO4 batteries

Post by antiscab »

hi Peter,

although it is recommended that TS cells are mounted with strapping, this isn't critical unless you are fast charging (2-3C) and or using very high discharge rates (3C+).

Matt
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PeterR
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Correct mounting of LiFePO4 batteries

Post by PeterR »

Thanks Guys.
The batteries will now be mounted securely in a frame, without spacers.
Peter

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Correct mounting of LiFePO4 batteries

Post by Nevilleh »

I queried TS about mounting LFPs horizontally and they said if I want to mount them that way, they need special construction and if I specify that when ordering they will supply cells suitable for H mtg at a 10% premium.

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acmotor
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Correct mounting of LiFePO4 batteries

Post by acmotor »

The standard LFP cells are definitely designed for vertical mounting only.

The Liquid Electrolyte is a Solution of Lithium hexafluorophosphate in a mixture of organic solvents ...
( Ethylene Carbonate (EC) + DiEthyl Carbonate (DMC) + DiEthyl Carbonate (DEC) + Ethyl Acetate (EA) ).

The cells are constructed with a spring loaded vent valve (centre top) The valve is not intended to be fluid tight and if the cell vents while horizontal or upside down then electrolyte solution will be expelled.
(I've pulled one of mine apart to examine the valve etc !)

The other issue being that the electrolyte will not be completely covering the plate construction internally if the cell is horizontal.

The cell may appear to work (at first) but long term damage will result. Thus Thundersky have offered a 'special construction' as in Nevilleh's post.

This is all from the electrolyte point of view. There may be mechanical concerns as well. For instance, how high can you stack cells on their side ?

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Last edited by acmotor on Sun, 08 Feb 2009, 15:40, edited 1 time in total.
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evric
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Correct mounting of LiFePO4 batteries

Post by evric »

Hi, has anyone got 2 faulty TS LFP 90Ah cells that they don't want. I need them as spaces for my layout. I could make spacers from lumps of wood but... Regards Ric
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antiscab
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Correct mounting of LiFePO4 batteries

Post by antiscab »

i see curiosity has gotten the better of u, Tuarn.
was that cell failed before you cracked it open?
or didnt u tear it completely apart?

Matt
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2017 Renault zoe - 25'000km
2007 vectrix - 156'000km
1998 prius - needs Batt
1999 Prius - needs batt
2000 prius - has 200 x headway 38120 cells

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acmotor
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Correct mounting of LiFePO4 batteries

Post by acmotor »

TS Cell is fully functional. I have no failed cells (touch wood) but these are for the Rodeo so haven't been used in anger yet.

The TS logo badge is weakly stuck over the vent cover with DS tape. This cover is a simple screw down plug, so no cracking open required. Electrolyte vapour is heavier than air so there is no issue with lifting the valve with cell upright.

I believe Rob has cut open a TS cell and there are plenty of pics of the inside on the net.
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HeadsUp
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Correct mounting of LiFePO4 batteries

Post by HeadsUp »

are you guys using the Thundersky BMS , or did you find something better than their unit ?

thankyou

antiscab
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Correct mounting of LiFePO4 batteries

Post by antiscab »

gday headsup,

i cant speak for acmotor (i think hes making his own) but i use Rod Dilkes BMS: www.evpower.com.au
its been fairly reliable thus far (im at 16500km).

Matt
Matt
2017 Renault zoe - 25'000km
2007 vectrix - 156'000km
1998 prius - needs Batt
1999 Prius - needs batt
2000 prius - has 200 x headway 38120 cells

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Correct mounting of LiFePO4 batteries

Post by coulomb »

HeadsUp wrote: are you guys using the Thundersky BMS , or did you find something better than their unit ?

Weber and I have considered all sorts of BMS options, but our current thinking is to keep it quite simple. Something like acmotor's home grown BMS. The main reason is cost and time: if we end up with ~200 cells, we'll end up with an awful lot of BMS electronics.

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