NexPower V3 hybrid battery unveil - Sodium-ion battery

It all depends on your expectations. From a mathematical point of view, this is definitely a non-linear graph. But if you look at other types of batteries, then this is quite a linear characteristic.

 

Certainly, in a graph like that, a person could say "this is almost linear", without sounding bonkers, if talking about the portion between Vexp and Vnom. That'd be, eyeballing it, the portion between about 1.28 and 1.22 V in the graph you attached to #99 (on the red trace).

The portion between Vexp and Vfull is a lot harder to call "almost linear" with a straight face, and to try to take the whole region Vfull to Vnom and call it "almost linear" would pretty much demand giving the word 'almost' hazardous-duty pay.

If I remember right, this little detour first arose from Fred_H's question in #94, which I think might be restated as a comparison of two ways to estimate the difference in usable capacity between two battery chemistries if the BMS keeps the working region between the same two voltage breakpoints.

It looks like Fred_H, following mudder, went with an early conversion from V to SoC for each chemistry, and then compared the resulting ΔSoCs.

I think that Fred_H, in #94, is asking why/how it improves the estimate any to use ΔV and a stated assumption that "the characteristic is linear", when the stated voltage ranges extend well up past Vexp and therefore the relationship may not fit the stated assumption very well.

It does seem to me the approach mudder and Fred_H used may depend less on the assumption of linearity.

 

Welcome to the world of analog signals. Such a signal is subsequently approximated by the BMS and forms a linear signal.

Simply taking 30% of the SOC is also not entirely correct. Look at the graph

 

If the BMS linearizes the input according to a known curve, then it is doing what it's supposed to, and that's not the same as us treating the curve as if it's a line.

If the shape of the SIB curve is that radically different from the shape of the NiMH curve, that'll be another fly in the ointment when trying to interpret what the NiMH-calibrated BMS thinks the SoC of the SIB is—another topic for another day.

Nonetheless, the basics of the mudder/Fred_H approach to estimating the usable capacity still seem sound: find the voltages corresponding to 40% and 80% SoC according to an NiMH curve, then find the SoCs corresponding to those voltages, using an SIB curve, then subtract to find the difference of those SoCs.

Maybe it'll come out something other than 30% if done carefully using the SIB graph above. (I haven't done it here just now.)

 

In the context of Voc->SoC lookup:
-battery people would call this region 'flat', as the small voltage delta makes SoC estimation difficult.
-battery people would typically reserve the word "linear" for a region with a larger constant-slope area.

My approach is back-of-the-envelope. I'm waiting to comment further until I have actual data from an actual V3 NexPower cell.

The discharge curves you posted are different than others I've seen. Here's a typical profile I've seen:

Here you can see that the cell is essentially linear all the way down to an inflection point at ~60% DoD.

 

seriously I check my oil and tire pressure every week and wash my inside front windshield quite often, just me.

 

Congratulations Jack!
NexPower Energy Inc. Recognized with a 2024 Global Recognition Award for Advancing Sustainable Transportation Technology | Markets Insider

 

Maxed out at 73mpg on my thanksgiving drive today

Monitor showed average speed was 68mph but I was mostly doing 75mph.

 

This is what I wrote in another thread about the "Award" that Jack received:

 

Kind of like to have a Hollywood star on the cement side walk, you have to pay for the star first before you can even be presented it.

 

The "Award" is free. Winners are notified by email that they have won. That is all that you receive for free (an email saying that you won). If you want the certificate, you must pay for it. If you want the crystal trophy with your name on it, you must pay for it. If you want publicity, you must pay for it, etc.

The "Global Recognition Award" is a trademark.

Like I already stated, it does not look like much of a "Award". Just search for "2024 Global Recognition Award" and you find a list of many individuals that I assumed paid for the publicity to boost their resume or image on the web.

 

??????? So how many award have you gotten?

 

I have not received any Global Recognition Awards because I have not applied yet.

 

The best part about the internet is that people take the time to put someone down or shame them.

It really makes me wonder, how minuscule is your life off the internet? I know you all see them; the ones whose comments never shine any positive rays or the ones who clearly have Karen energy. It's like, wow, he really got under your skin enough to go out and attempt to do something you felt very vigilante about. Do you wear a cape?

 

42 miles of ~3000 ft elevation drop with a tailwind.
Anyone could do that, with the special situation you had for this picture.

You were not on a level highway with no winds driving at 75mph.
And since it's a hybrid, all the power came from the gasoline. The battery did not create power.

 

1.Yes, a PHEV option kit would be the only reason to embrace higher capacity cells. But how would that play with the stock BCM?

2. And where would the power come from for there to be a '1kW capacitor'. And wouldn't that cap really need a kWh spec to be useful?
A quick spark of 1kW of power isn't going to do much to a battery pack.

It's a hybrid. All the power comes from that stinky stuff, unless you have a way to turn it into a PHEV.

 

As a previous owner of two G1 Insights, I'm aware of the early modder's efforts. (I really wanted ol'Mike Whatshisface's motor power control system on my first one. But I grew up and bought a factory EV)

I really question sending 24kW to that little stator. And I really question the health of the magnets in the flywheel/rotor.
Heating magnets to high temps will harm them.
24kW to the Stator does not mean you are getting ~24kW of power at the flywheel/rotor.

 

contrary to popular belief... the BCM is very smart and long as it gets the same volts.... higher capacity you shall have... these days, I found a hv battery out of a newer toyo vehicle that will or should get me 50kWh in my Plugin...

 

Yeah, an electrical engineer explained the size of capacitor you'd need to quick charge a Prius size Sodium-Ion pack and a car would be too small to carry something that massive.