Posts: 82
Joined: Tue Sep 18, 2018 1:45 pm
Delivery Date: 18 Sep 2018
Location: Toledo, Ohio

Re: Replace individual battery cells to renew/increase capacity

Sat May 04, 2019 5:12 am

The research for this projects feasibility has been hindered by the high cost of 3.75v nominal lithium cells. even the consumer "d" size lithium cells are too expensive at the quantity needed, I cannot get the price lower than $250++/7.4v/100ah 2012 module. the problem is that buying at end consumer quantities it's hard to get the price down to what i am willing to pay. the inability of business to sell (beyond pre orders that are endlessly delayed) supplemental and replacement packs speaks to the difficulty of this. the next problem is that the NMC battery chemistry, and its higher cost, are becoming more dis-favored in the market place so innovation is not as high as LiFe and LiTi, which is driving the prices down on these chemistries. there was some of papers on saving higher voltage Lithium cells at SAE congress this year, one was using fluoridated electrolyte, one using dynamic charging strategies, but these 'future' battery techs do little to save 2011-2013 leafs that are getting to the end of battery life in the next few years.

for an unrelated project i'm look at 60mm diameter 280mm long cylindrical LiFePo4 cells that are priced lower than lead acid, and if they are not fake garbage (which they probably are) then maybe that is a way to go, either as a 110-series pack replacement to reclaim the traction pack space, or as a pack supplement with >100% of the new pack capacity. also the pusher trailer idea has merit, either with the LiFe batteries or a propane-fueled generator.

Posts: 13204
Joined: Wed May 22, 2013 3:17 am
Delivery Date: 30 Apr 2018
Location: Upstate New York, US

Re: Replace individual battery cells to renew/increase capacity

Sat May 04, 2019 12:34 pm

LiFePo4 is a good, relatively safe chemistry, but it has a lower energy density and is thus not used much in EVs. (I have LiFePo4 packs on my older electric bicycles.) If you use a pusher trailer, they may be feasible, though.
Scarlet Ember 2018 Leaf SL W/ Pro Pilot
2009 Vectrix VX-1 W/18 Leaf modules, & 3 EZIP E-bicycles.
PLEASE don't PM me with Leaf questions. Just post in the topic that seems most appropriate.

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