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RegGuheert
Posts: 5583
Joined: Mon Mar 19, 2012 4:12 am
Delivery Date: 16 Mar 2012
Leaf Number: 5926
Location: Northern VA

Re: About that 40 kWh Battery

Mon Oct 23, 2017 5:13 pm

pipestem wrote: That sounds like a lot less room to dissipate heat.
It sounds like the same amount of room. These batteries will not dissipate more heat unless they have more internal resistance. Likely they have less because that's the direction you need to move with technology.

But there are many, many things that can be done to reduce the capacity loss of these batteries. Unfortunately, some of those things require a trade-off of capacity to achieve them. Other changes can be made by putting additives into the electrolyte. Unfortunately, Nissan did not take my advice to hire Dr. Jeff Dahn (inventor of NMC chemistry), who is on the forefront of greatly improving the issue of capacity fade in Li-ion batteries. Instead, they did not pursue him and Tesla has tied him up in a five-year exclusive agreement. Within the first year, Dahn came up with improvements which reduced the capacity fade in Tesla's batteries by more than half.
pipestem wrote:Do we have any official references on specifics of battery composition and changes over the years. The only thing I found was that message board post from a Nissan employee saying something like replacement batteries would have the improved composition, but no specifics. What do we really know with citations?
We know that Nissan has moved from LMO chemistry to NMC chemistry, just like Chevrolet did with the Volt. Search the forum for LMO or NMC to learn more.
RegGuheert
2011 Leaf SL Demo vehicle
2011 miles at purchase. 10K miles on Apr 14, 2013. 20K miles (55.7Ah) on Aug 7, 2014, 30K miles (52.0Ah) on Dec 30, 2015, 40K miles (49.8Ah) on Feb 8, 2017.
Enphase Inverter Measured MTBF: M190, M215, M250, S280

pipestem
Posts: 14
Joined: Tue Sep 26, 2017 6:03 pm
Delivery Date: 23 Sep 2017
Leaf Number: 327753

Re: About that 40 kWh Battery

Mon Oct 30, 2017 11:48 pm

RegGuheert wrote:
pipestem wrote: That sounds like a lot less room to dissipate heat.
It sounds like the same amount of room. These batteries will not dissipate more heat unless they have more internal resistance. Likely they have less because that's the direction you need to move with technology.

But there are many, many things that can be done to reduce the capacity loss of these batteries. Unfortunately, some of those things require a trade-off of capacity to achieve them. Other changes can be made by putting additives into the electrolyte. Unfortunately, Nissan did not take my advice to hire Dr. Jeff Dahn (inventor of NMC chemistry), who is on the forefront of greatly improving the issue of capacity fade in Li-ion batteries. Instead, they did not pursue him and Tesla has tied him up in a five-year exclusive agreement. Within the first year, Dahn came up with improvements which reduced the capacity fade in Tesla's batteries by more than half.
pipestem wrote:Do we have any official references on specifics of battery composition and changes over the years. The only thing I found was that message board post from a Nissan employee saying something like replacement batteries would have the improved composition, but no specifics. What do we really know with citations?
We know that Nissan has moved from LMO chemistry to NMC chemistry, just like Chevrolet did with the Volt. Search the forum for LMO or NMC to learn more.


Thanks. I'm not questioning the difference between LMO an NMC, there is plenty of information about that. I am questioning if anyone has original source material from Nissan saying the original batteries were LMO, or they did exactly something to make that Lizzard, or they now use NMC., performance characteristics, etc...., or some independent technical evaluation. Something like an SAE or JSAE report, or a Nissan technical bulletin, anything worthy of a citation and peer review. I like those kinds of things. Cheers.
2015 Red Leaf S. Yes the red is important.

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