Tesla using LFP in China

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brendon_m
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Tesla using LFP in China

Post by brendon_m »

Looks like Tesla are going to take a range hit on the model 3 in China in order to lower costs even more

https://www.mining.com/teslas-china-sur ... ice-bulls/

Also clickbaity headline saying Tesla has shocked the world by not using cobalt, like Tesla hasn't been saying for years that they're trying to remove cobalt from their cells. And it's only for the China model 3's, I'm sure cobalt and Nickel miners will still be able to sell as much as they can dig up.

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Re: Tesla using LFP in China

Post by HuffnPuff »

They can afford a bit of a range hit. Marketers are still stuck on selling us more range is the only answer. If they could drop $10k off the price by reducing battery capacity and the public could be convinced that 200km is more than enough for a city commuter they’ll sell more.

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Re: Tesla using LFP in China

Post by brendon_m »

Agreed, especially if there was a DC fast charger network worth speaking of around here. I get by with 80km of range but a bit of a buffer would be nice. 150-200km I think is the sweet spot to not have "range anxiety". On the rare occasion I'm travelling (in an urban commuter car) I'd be happy to stop every 2ish hours.
Give me the option to go further (at a cost) but more importantly give me the option to save money (but sacrifice range)

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Re: Tesla using LFP in China

Post by jonescg »

It will only be cheaper because the battery is lower capacity. The $/kWh of LFP is actually higher than any nickel or cobalt based cathode. Should make them a bit less prone to fire at least, but the BMS will need to be updated.
I also read that they would be sourcing prismatic LFP from CATL. So the pack level energy density could be lower still?
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Re: Tesla using LFP in China

Post by coulomb »

jonescg wrote:
Fri, 21 Feb 2020, 06:49
I also read that they would be sourcing prismatic LFP from CATL.
Ah. That sounds like a government mandate. I wonder if that was made clear before the gigafactory was built?
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Re: Tesla using LFP in China

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brendon_m wrote:
Fri, 21 Feb 2020, 06:17
Agreed, especially if there was a DC fast charger network worth speaking of around here. I get by with 80km of range but a bit of a buffer would be nice. 150-200km I think is the sweet spot to not have "range anxiety". On the rare occasion I'm travelling (in an urban commuter car) I'd be happy to stop every 2ish hours.
Give me the option to go further (at a cost) but more importantly give me the option to save money (but sacrifice range)
Can't agree more. Second it!

I'm awaiting until someone sell their Ioniq, so I can get 2nd hand. I've heard newer Ioniq max-out at 50kW fast charging (compared to 100kW with earlier Ioniq?). I personally think 100kW would be perfect (coupled with infrastructure of course...).

With Ioniq super-efficiency, that adds roughly 12kWh, or 100km in 10-minute fast charge (@75kW). That is uber-perfect for me.

Give me 20kWh usable capacity EV with 100-ish kW fast charging capability and infrastructure, and cut 20k out of the price tag. That is the solution for me.

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Re: Tesla using LFP in China

Post by jonescg »

@Patti McBain has been driving her converted Focus for over 100,000 km and it's still putting out a useable range. If that's not an endorsement for the longevity of LFP (even if the energy density isn't great) I don't know what is.

The new Ioniq having a slower fast charge (50 kW instead of 70 kw, and it tapers sooner) didn't bother our purchase decision, because our charging needs are well within the limits of either.
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Re: Tesla using LFP in China

Post by brendon_m »

Rusdy wrote:
Fri, 21 Feb 2020, 09:05
Give me 20kWh usable capacity EV with 100-ish kW fast charging capability and infrastructure
That is the only real hold up I can see for small cars, smashing 100kW+ into a 20kWh battery. Its easy enough on a 100kWh pack, that's only 1C but into a 20kWh pack all of a sudden it's 5C :shock:

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Re: Tesla using LFP in China

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brendon_m wrote:
Fri, 21 Feb 2020, 10:57
Rusdy wrote:
Fri, 21 Feb 2020, 09:05
Give me 20kWh usable capacity EV with 100-ish kW fast charging capability and infrastructure
That is the only real hold up I can see for small cars, smashing 100kW+ into a 20kWh battery. Its easy enough on a 100kWh pack, that's only 1C but into a 20kWh pack all of a sudden it's 5C :shock:
Exactly, it isn't just range that suffers from a smaller capacity battery, voltage sag and very reduced range if the go fast pedal is thrashed too much. Once they make a cell that can handle 5CA and still maintain the full available capacity the battery pack can be offered on range alone, not range and performance

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Re: Tesla using LFP in China

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T1 Terry wrote:
Fri, 21 Feb 2020, 12:16
brendon_m wrote:
Fri, 21 Feb 2020, 10:57
Rusdy wrote:
Fri, 21 Feb 2020, 09:05
Give me 20kWh usable capacity EV with 100-ish kW fast charging capability and infrastructure
That is the only real hold up I can see for small cars, smashing 100kW+ into a 20kWh battery. Its easy enough on a 100kWh pack, that's only 1C but into a 20kWh pack all of a sudden it's 5C :shock:
... Once they make a cell that can handle 5CA and still maintain the full available capacity ...

T1 Terry
Forget 5C. I'm happy enough with battery that can hold 2C while charging after years of degradation.

My Leaf battery (albeit first gen), only can absorb 0.5C after merely a minute or so 'fast charging' (detailed blurb here

For lowly utilitarian like me, fast charging performance is far distant first requirement, instead of peak kW.

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Re: Tesla using LFP in China

Post by Rusdy »

jonescg wrote:
Fri, 21 Feb 2020, 10:53
... If that's not an endorsement for the longevity of LFP (even if the energy density isn't great) I don't know what is...
LFP is awesome indeed.

However, heat killed my first LFP. I was naively thought LFP is bulletproof, so I installed it as a starter battery in my previous Corolla. It killed it in 3 years (details here )

Engine bay is definitely wrong place to put any lithium :oops:

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Re: Tesla using LFP in China

Post by T1 Terry »

Rusdy wrote:
Sat, 22 Feb 2020, 20:16
jonescg wrote:
Fri, 21 Feb 2020, 10:53
... If that's not an endorsement for the longevity of LFP (even if the energy density isn't great) I don't know what is...
LFP is awesome indeed.

However, heat killed my first LFP. I was naively thought LFP is bulletproof, so I installed it as a starter battery in my previous Corolla. It killed it in 3 years (details here )

Engine bay is definitely wrong place to put any lithium :oops:
I have seen them with a really good insulation outside the box and airflow from outside directed inside the box toward the top and the exit at the bottom so any water that got in would be flushed out as well.
When we install the LFP/LYP cells in the front boot of a caravan, we add a vent hole from under neither the van, a flat type paper air filter and housing from a wreckers, modified to suit, and vents with fans to the outside at the top of the front boot or up through the tunnel boot above and vents outside each side with the fins facing away from the direction of travel. This seems to sort the heat issues we had, but they were mostly inverter shut downs as the climbed above the 70*C mark.

I'm still looking into using LTO cylindrical cells and pumping this stuff https://multimedia.3m.com/mws/media/199 ... -fluid.pdf through the cell enclosures to ensure they don't suffer heat stroke when fast charging or discharging.

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Re: Tesla using LFP in China

Post by francisco.shi »

It also seems they are going to use pouch cells instead of cylindrical.
The reason appears to be better backing density.
If they think the total pack energy density will be similar then the cylindrical cells must be doing very poorly compared to pouch for packing effecienty.

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Re: Tesla using LFP in China

Post by jonescg »

If you are forced to use LFP, then pouch cells offer better volumetric energy density over prismatic. Otherwise cylindrical NMC still leads the race.
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Re: Tesla using LFP in China

Post by antiscab »

I also wonder if they're putting as much effort into cooling the lfp battery
There may be some weight savings there, particularly if shifting from say liquid battery cooling to air cooling (same as the zoe design)
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Re: Tesla using LFP in China

Post by francisco.shi »

Pouch cells are much easier to cool and pack.
My battery pack complete with case is 380 kg for a 70kwh pack. That is 184wh/kg for the complete battery including the case. It has about 10 times the cooling efficiency and 1/3 of the internal resistance (including busbars and interconnects) of the Tesla packs and I am using cells with 230wh/kg and Tesla uses 300wh/kg cells. So pouch cells are way better than cylindrical cells for cooling and interconnect.

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Re: Tesla using LFP in China

Post by jonescg »

francisco.shi wrote:
Thu, 27 Feb 2020, 06:01
Pouch cells are much easier to cool and pack.
My battery pack complete with case is 380 kg for a 70kwh pack. That is 184wh/kg for the complete battery including the case. It has about 10 times the cooling efficiency and 1/3 of the internal resistance (including busbars and interconnects) of the Tesla packs and I am using cells with 230wh/kg and Tesla uses 300wh/kg cells. So pouch cells are way better than cylindrical cells for cooling and interconnect.
I'd say any OEM battery is built with lots of packaging overhead to give it robustness. Time will tell how the LG built battery packs stand up to the rigours of an automotive environment. The true benefit of a cylindrical cell is the hoop strength of the can, preventing major deformation. Pouches and prismatics don't have that intrinsic to their shape, so additional clamping stuff is required.

But on a cell level, cylindrical cells have the same specific energy (Wh/kg) and better volumetric energy density (Wh/l) than pouches, even when factoring in the missing space between. Usually with cars and motorcycles especially it comes down to volume limitations, not weight. That said the LG cells are very good. The jury is still out as to whether cylindrical/pouch/prismatic is best, because it really depends on the application. Pouch cells were traditionally more expensive to make because they involved far more manual assembly steps, but that's changing too.

As for cooling, the amount of heat to be removed is quite small, and even a poor cooling system will be better than no cooling system. I was pleasantly surprised to see the cell base cooling system I used on the Prelude work so well.
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